Co-reporter:Zhaodong Huang, Hongshuai Hou, Chao Wang, Simin Li, Yun Zhang, and Xiaobo Ji
Chemistry of Materials September 12, 2017 Volume 29(Issue 17) pp:7313-7313
Publication Date(Web):August 14, 2017
DOI:10.1021/acs.chemmater.7b02193
High specific capacity and long cycling life of anode materials still remain major challenges in the development of sodium-ion batteries (SIBs). Nowadays, transition metal phosphides have been reckoned as promising anodes in view of their high theoretical specific capacities, low potential for sodium storage, and superior conductivity. Herein, molybdenum phosphide (MoP) nanorods wrapped with thin carbon layer have been prepared and applied as an anode for SIBs. By utilizing in situ X-ray diffraction technology, a conversion-type mechanism of MoP anode has been disclosed. This kind of MoP electrode exhibits extraordinary electrochemical properties, including excellent cycling performance with a discharge capacity of 398.4 mA h g–1 at a current density of 100 mA g–1 after 800 cycles, and remarkable rate capabilities, which remain 104.5 mA g–1 at 1600 mA h g–1 even after 10 000 loops. The distinguished performances stem from synergetic merits of the morphology, structure, and mechanism of MoP. It is expected that MoP will be a promising anode material for SIBs and this work would provide theoretical basis for the scalable research and applications of MoP-based anode materials for SIBs.
Co-reporter:Peng Ge, Xiaoyu Cao, Hongshuai Hou, Sijie Li, and Xiaobo Ji
ACS Applied Materials & Interfaces October 11, 2017 Volume 9(Issue 40) pp:34979-34979
Publication Date(Web):September 22, 2017
DOI:10.1021/acsami.7b10886
One-dimensional Sb2Se3/C rods are prepared through self-assembly by inducing anisotropy, and their corresponding sodium storage behaviors are evaluated, presenting excellent electrochemical performances with superior cycling stability and rate capability. Sb2Se3 delivers a high initial charge capacity of 657.6 mA h g–1 at a current density of 0.2 A g–1 between 2.5 and 0.01 V. After 100 cycles, the reversible capacity of Sb2Se3/C is still retained at 485.2 mA h g–1. Even at a high rate current density of 2.0 A g–1, the charge capacity is still retained at 311.5 mA h g–1. Through the analysis of cyclic voltammetry and in situ electrochemical impedance spectroscopy, the in-depth understanding of high rate performances is explored effectively. Briefly, the sodium storage performance of Sb2Se3/C is observably enhanced, benefiting from the 1D structure and the introduction of a carbon layer with robust structure stability and conductivity.Keywords: carbon coating; conductivity; electrochemistry; Sb2Se3; sodium-ion batteries;
Co-reporter:Zhaodong Huang;Hongshuai Hou;Yan Zhang;Chao Wang;Xiaoqing Qiu
Advanced Materials 2017 Volume 29(Issue 34) pp:
Publication Date(Web):2017/09/01
DOI:10.1002/adma.201702372
Liquid phase exfoliation of few-layer phosphorene (FL-P) is extensively explored in recent years. Nevertheless, their deficiencies such as ultralong sonication time, limited flake size distribution, and uncontrollable thicknesses are major hurdles for the development of phosphorene-based materials. Herein, electrochemical cationic intercalation has been introduced to prepare phosphorene, through which large-area FL-P without surface functional groups can be efficiently attained (less than 1 h). More importantly, its layer number (from 2 to 11 layers) can be manipulated by changing the applied potential. The as-obtained phosphorene delivers superior sodium-storage performances when directly utilized as an anode material in sodium-ion batteries. This electrochemical cation insertion method to prepare phosphorene should greatly facilitate the development of phosphorene-based technologies. Moreover, this work provides the possibility for the scalable preparation of monolayer 2D materials by exploring intercalation ions. Additionally, the successful electrochemical exfoliation of phosphorene can promote the application of electrochemical exfoliation in other 2D materials.
Co-reporter:Zehua Wang;Xiaoyu Cao;Peng Ge;Limin Zhu;Lingling Xie;Hongshuai Hou;Xiaoqing Qiu
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 14) pp:6693-6699
Publication Date(Web):2017/07/10
DOI:10.1039/C7NJ01230F
Hollow-sphere ZnSe is successfully obtained through Ostwald ripening. Carbon nanoparticles are designed and utilized to form a wrapped carbon network as a conductive buffering matrix by subsequent annealing. The ZnSe/C composites, as anode materials for lithium-ion batteries (LIBs), exhibit excellent Li+ storage properties, delivering a high reversible capacity of 573.7 mA h g−1 at 1.0 A g−1 after 800 cycles. Even upon increasing the high current density to 20.0 A g−1, the reversible capacity can achieve 318.8 mA h g−1 after 5000 cycles. The superior rate capability is confirmed through the current density return from 20.0 to 1.0 A g−1, and ZnSe/C composites still recover up to 469 mA h g−1, with a retention of 92%. The enhanced electrochemical performances of ZnSe/C composites are attributed to the unique structure and the introduction of conductive carbon networks, which can improve the Li+ diffusion coefficient in the insertion and extraction process. Furthermore, the interconnected network also alleviates the volume variation during cycling and further enhances the structural stability.
Co-reporter:Weizhen Yu;Hongshuai Hou;Zhiling Xin;Shuo Niu;Yanan Xie;Lidong Shao
RSC Advances (2011-Present) 2017 vol. 7(Issue 25) pp:15309-15314
Publication Date(Web):2017/03/06
DOI:10.1039/C7RA00123A
In this work, palladium nanoparticles supported on 3D porous carbon frameworks (Pd/PCFs) were used in the selective hydrogenation of phenylacetylene. Catalytic tests conducted in a continuous-flow reactor coupled with theoretical calculations, HPLC and characterization methods helped to elucidate the structural origins of the observed selectivity patterns. A 62% selectivity towards styrene with a 93% conversion was observed in the hydrogenation of phenylacetylene at 20 °C and 3 bar for a hydrogen flow rate of 12 mL min−1 and a reaction liquid flow rate of 0.9 mL min−1. Commercially available Pd-based reference catalysts were tested under the same conditions in phenylacetylene hydrogenation, and the performance of 3 wt% Pd/PCFs was substantiated by studying the geometrical structure of PCFs and the stability of supported Pd nanoparticles under reaction conditions.
Co-reporter:Juan Wang;Qi Zhao;Hongshuai Hou;Yifei Wu;Weizhen Yu;Lidong Shao
RSC Advances (2011-Present) 2017 vol. 7(Issue 23) pp:14152-14158
Publication Date(Web):2017/02/28
DOI:10.1039/C7RA00590C
In this work, nitrogen-doped honeycomb-like carbon framework (CNFs) is synthesized by a low-cost and scalable method. Ni nanoparticles are then supported on CNFs (CNFs–Ni) as a catalyst for methanol oxidation. In addition to the enhanced mass activity, both the onset and oxidation peak potentials of CNFs–Ni for methanol oxidation shift negatively in comparison to its non-doped counterpart, CFs–Ni. We propose that the small particle size, uniform dispersion, and electronic effect arising from the electron interactions between CNFs and Ni contribute to the improved electrocatalytic performance.
Co-reporter:Hongshuai Hou;Guoqiang Zou;Peng Ge;Ganggang Zhao;Weifeng Wei;Lanping Huang
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 22) pp:13724-13731
Publication Date(Web):2017/11/06
DOI:10.1039/C7NJ02105D
As an anode material for sodium-ion batteries (SIBs), antimony (Sb) has attracted significant interest due to its high theoretical specific capacity. However, it suffers from a huge volume change during the sodiation–desodiation process that leads to poor cyclability. Herein, cross-linked carbon nanosheet frameworks (CCNFs) and Sb nanoparticles (NPs) were combined to construct a high-performance anode material for SIBs. In this composite, Sb nanoparticles were tightly anchored on the carbon frameworks; this provided enhanced structural stability to Sb and prevented the agglomeration during the charge–discharge process. Sb provides a high specific capacity, and the carbon frameworks ensure structural integrity and conductive networks. Moreover, due to this synergistic effect, the as-prepared Sb/CCNFs composite exhibits an excellent cycle stability and rate performances. Considering both the capacity and rate property, the overall performances of the obtained Sb/CCNFs reach the highest level in comparison with those of the reported Sb/C composites. The reversible (charge) capacity can remain 549.3 mA h g−1 after 100 cycles at a current density of 100 mA g−1. Moreover, a superior rate performance is observed as the reversible capacity still reaches 318 mA h g−1 at a high current density of 3200 mA g−1. Therefore, this study proposes an effective methodology to improve the key performances of the SIB anode.
Co-reporter:Guoqiang Zou;Hongshuai Hou;Ganggang Zhao;Zhaodong Huang;Peng Ge
Green Chemistry (1999-Present) 2017 vol. 19(Issue 19) pp:4622-4632
Publication Date(Web):2017/10/02
DOI:10.1039/C7GC01942D
The conventional strategies for obtaining S/N-codoped carbon materials suffer from a series of problems caused by their complicated experimental procedures. Here, S,N-codoped carbon nanosheets were firstly prepared by a solvent-free one-pot method, displaying an ultra-thin sheet-like structure, a tunable interlayer distance ranging from 0.37 nm to 0.41 nm, and a large surface area up to 809 m2 g−1. When they were used as an anode for sodium-ion batteries (SIBs), an outstanding sodium-ion storage performance of 380 mA h g−1 was acquired at 100 mA g−1, which can be attributed to the expanded interlayer distance caused by the introduction of the large covalent radius-sulfur. The initial coulombic efficiency improved to 60.9%, which may benefit from N-doping. Most importantly, an excellent rate capability of ∼178 mA h g−1 was observed at a current density of 5 A g−1 after 5000 cycles, which is among best of the state-of-the-art carbon-based SIBs. Interestingly, the morphology of the obtained carbon materials can be tuned from bulk to flake by adjusting the sulfur content or temperature. Given this, this work provides a new method to construct co-doped carbon (especially tri-doped and multi-doped carbon) and shows that the strategy of co-doping of heteroatoms can effectively optimize the nano/microstructure and enhance the rate capability of the carbon materials.
Co-reporter:Sijie Li, Peng Ge, Chenyang Zhang, Wei Sun, Hongshuai Hou, Xiaobo Ji
Journal of Power Sources 2017 Volume 366(Volume 366) pp:
Publication Date(Web):31 October 2017
DOI:10.1016/j.jpowsour.2017.09.032
•As-designed Na3V2(PO4)3/C was firstly obtained through rheological phase reaction.•The double carbon layers stabilize structure and improve conductivity well.•The Na3V2(PO4)3/C −800 exhibits 73 mAh g−1 at 100 C and 55 mAh g−1 at 200 C.•The Na3V2(PO4)3/C −800 shows a retention of 72.7% over 12 000 cycles at 200 C.Na3V2(PO4)3 (NVP) is a very promising cathode material in sodium ion battery for rapidly emerging large-scale energy storage with its classical 3D NASCION structure. However, the cycling life and rate performances are restricted its low electronic conductivity. To overcome these, the double carbon-wrapped Na3V2(PO4)3 composite is firstly designed through rheological phase approach, delivering enhanced electrochemical properties. The unique double carbon layers are composed of uniform amorphous carbons as protecting framework for stabilizing the structure, as well as the graphitized carbon sheets playing the role of conductive network for better electronic conductivity. This double carbon-wrapped Na3V2(PO4)3 composite exhibits a high reversible capacity of 99.8 mAh g−1 over 500 cycles at 1 C (110 mA g−1), yielding the coulombic efficiency of ∼99.8%. Meanwhile, it displays an initial capacity of 73 mAh g−1 at 100 C and remains 55 mAh g−1 at an ultra-rate of 200 C. Even after cycling at 200 C over 12 000 cycles, the Na+-storage capacity of 40 mAh g−1 with a retention of 72.7% is still obtained, highlighting its excellent long cycling life and remarkable rate performances.
Co-reporter:Jun Chen, Guoqiang Zou, Hongshuai Hou, Yan Zhang, Zhaodong Huang and Xiaobo Ji
Journal of Materials Chemistry A 2016 vol. 4(Issue 32) pp:12591-12601
Publication Date(Web):19 Jul 2016
DOI:10.1039/C6TA03505A
Hierarchical anatase TiO2 homogeneously tuned by using carbon through Ti–C bonds has been designed, exploiting carbon quantum dots as uniform carbon additives and functionalization inducers for structure tailoring and surface modification. The fabricated pinecone-like structure constructed by ultrafine subunits presents a highly increased surface area (202.4 m2 g−1) and abundant mesopores. Surface bonded carbon significantly boosts its electronic conductivity derived from both the conductive carbon and accompanied oxygen vacancies. When utilized in sodium-ion batteries, it delivers a high reversible specific capacity of 264.1 mA h g−1 at a rate of 0.1C (33.6 mA g−1) and still maintains 108.2 mA h g−1 even after 2000 cycles at 10C with a retention of 94.7% outstandingly. Notably, its Na+ intercalation pseudocapacitive behavior is enhanced by the modulated TiO2/carbon interfaces, facilitating a fast (de-)sodiation process. Combining the elaborate hierarchical structure with the unique surface composition, synergetic merits are noticed when the promoted kinetics, improved electronic conductivity, increased electrolyte penetration areas and shortened Na+ diffusion length are achieved simultaneously, giving rise to remarkable high-rate capabilities and long-term cyclability.
Co-reporter:Jun Chen, Zhiying Ding, Chao Wang, Hongshuai Hou, Yan Zhang, Chiwei Wang, Guoqiang Zou, and Xiaobo Ji
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 14) pp:9142
Publication Date(Web):March 23, 2016
DOI:10.1021/acsami.6b01183
Nanostructured black anatase titania with oxygen vacancies (OVs) is efficiently obtained and employed as an anode in sodium-ion batteries (SIBs) for the first time. The incorporation of OVs into TiO2 is demonstrated to render considerably enhanced-rate performances, higher initial capacities, and an accelerated electrochemical activation process during cycling, derived from the boosted intrinsic electric conductivity and improved kinetics of Na uptake. Bestowed with the integrated merits of OVs and shortened Na ion diffusion length in the nanostructure, black titania delivers a reversible specific capacity of 207.6 mAh g–1 at 0.2 C, retains 99.1% over 500 cycles at 1 C stably, and still maintains 91.2 mAh g–1 even at the high rate of 20 C. Density functional theory (DFT) calculations suggest that the lower sodiation energy barrier of anatase with OVs enables a more favorable Na intercalation into black anatase. Thus, it is of great significance to introduce OVs into TiO2 to stimulate ultrafast and durable sodium-storage properties, which also offers a potential strategy to project more superior electrodes, utilizing internal defects.Keywords: anode; black anatase; oxygen vacancies; rate performances; sodium-ion batteries;
Co-reporter:Guoqiang Zou, Jun Chen, Yan Zhang, Chao Wang, Zhaodong Huang, Simin Li, Hanxiao Liao, Jufeng Wang, Xiaobo Ji
Journal of Power Sources 2016 Volume 325() pp:25-34
Publication Date(Web):1 September 2016
DOI:10.1016/j.jpowsour.2016.06.017
•The CRT was firstly utilized in the sodium-ion batteries as anode.•This material showed stable structure and good electronic conductivity.•Excellent storage performance for SIBs of ∼70 mAh g−1 at 20 C after 2000 cycles.•The CRT was prepared by an in-situ pyrolysis of Ti-MOF.Carbon-coated rutile titanium dioxide (CRT) was fabricated through an in-situ pyrolysis of titanium-based metal organic framework (Ti8O8(OH)4[O2CC6H4CO2]6) crystals. Benefiting from the TiOC skeleton structure of titanium-based metal organic framework, the CRT possesses abundant channels and micro/mesopores with the diameters ranging from 1.06 to 4.14 nm, shows larger specific surface area (245 m2 g−1) and better electronic conductivity compared with pure titanium dioxide (12.8 m2 g−1). When applied as anode material for sodium-ion batteries, the CRT electrode exhibits a high cycling performance with a reversible capacity of ∼175 mAh g−1 at 0.5 C-rate after 200 cycles, and obtains an excellent rate capability of ∼70 mAh g−1 after 2000 cycles even at a specific current of 3360 mA g−1(20 C-rate). The outstanding rate capability can be attributed to the carbon-coated structure, which may effectively prevent aggregation of the titanium dioxide nanoparticles, accelerate the mass transfer of Na+ and speed up the charge transfer rate. Considering these advantages of this particular framework structure, the CRT can serve as an alternative anode material for the industrial application of SIBs.
Co-reporter:Yan Zhang, Hongshuai Hou, Xuming Yang, Jun Chen, Mingjun Jing, Zhibin Wu, Xinnan Jia, Xiaobo Ji
Journal of Power Sources 2016 Volume 305() pp:200-208
Publication Date(Web):15 February 2016
DOI:10.1016/j.jpowsour.2015.11.101
•NTO cuboid is firstly prepared by hydrothermal method.•NTO cuboid is employed for anode electrode in SIBs.•The sodium storage properties are explored by employing different binders.•Enhanced sodium storage behavior is obtained for the electrode with CMC binder.Sodium titanate (Na2Ti6O13) cuboid is successfully prepared and employed for anode electrode materials in sodium-ion batteries (SIBs). Their sodium storage properties are presented by undertaking polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC) as different binders. At a current density of 0.1 C, the sodium titanate cuboid with CMC and PVDF exhibits discharge capacity of 269.5 mAh g−1 and 251.0 mAh g−1, respectively. At the 200th charge/discharge cycle, the reserved discharge capacity for Sodium titanate cuboid electrode with CMC binder is 173.6 mAh g−1, amounting to a capacity retention of 94.4%, much higher than that employing PVDF as binder (the discharge capacity of 69.3 mAh g−1 and the capacity retention of 54.1%). The rate capability test and the Coulombic efficiency data also manifest that the Sodium titanate cuboid utilizing CMC as binder is superior to the ones with PVDF. These enhanced electrochemical performance mainly derive from the strong cohesive strength of CMC binder and the swellability of PVDF binder, verifying the importance of a binder to the optimization of sodium storage behavior.Na2Ti6O13 (NTO) cuboid is successfully prepared and employed for negative electrode materials in sodium-ion battery (SIB). The electrodes when carboxymethyl cellulose (CMC) employed as the binder manifested the enhanced sodium storage performances in comparison with that of polyvinylidene fluoride (PVDF) binder.
Co-reporter:Zhaodong Huang, Hongshuai Hou, Guoqiang Zou, Jun Chen, Yan Zhang, Hanxiao Liao, Simin Li, Xiaobo Ji
Electrochimica Acta 2016 Volume 214() pp:156-164
Publication Date(Web):1 October 2016
DOI:10.1016/j.electacta.2016.08.040
•3D porous carbon encapsulated SnO2 nanocomposite is prepared via an efficient and facile in situ methodology.•The composite exhibits remarkable cycle stability and notable rate capacities.•This efficient in situ approach can potentially be applied to obtain other anode materials.3D porous carbon encapsulated SnO2 nanoparticles composite (SnO2-PC) prepared by an efficient in situ methodology was applied as anode for sodium ion batteries (SIBs). It delivered a high reversible specific capacity of 280.1 mAh g−1 after 250 cycles at a current density of 100 mA g−1, with ultrahigh capacity retention of 91.63%. Notably, it can Exhibit 100 mAh g−1 after 1000 cycles even at a high current density of 1600 mA g−1. These greatly enhanced electrochemical properties of SnO2-PC composite can be attributed to the superior structure that the electrical conductivity of the composite was improved by the porous carbon matrix, moreover, it can serve as a cushion during the process of Na ion insertion/extraction into the composite. Significantly, this kind of in situ synthesis method is portable for other similar composite.
Co-reporter:Jun Chen, Guoqiang Zou, Yan Zhang, Weixin Song, Hongshuai Hou, Zhaodong Huang, Hanxiao Liao, Simin Li, Xiaobo Ji
Electrochimica Acta 2016 Volume 196() pp:405-412
Publication Date(Web):1 April 2016
DOI:10.1016/j.electacta.2016.03.014
A facile route to improve the lithium-storage properties of flake graphite (FG) is proposed through coating pyrolysis carbon from polyvinylidene fluoride (PVDF) assisted by KOH activation. The interplanar distance between the graphene sheets of activated PVDF/FG is enlarged, effectively suppressing the electrode deformation during lithium (de)-intercalation. More edge and porous structures of PVDF/FG arising from KOH activation on graphite flakes contribute to improved electron and ion transport, leading to great improvement in its rate and cycling performances. The initial specific capacity of the activated PVDF/FG is 476.6 mAh g−1 at 50 mA g−1 and when the current increases to 1000 mA g−1, the value still retains 142.6 mAh g−1.
Co-reporter:Guoqiang Zou, Xinnan Jia, Zhaodong Huang, Simin Li, Hanxiao Liao, Hongshuai Hou, Lanping Huang, Xiaobo Ji
Electrochimica Acta 2016 Volume 196() pp:413-421
Publication Date(Web):1 April 2016
DOI:10.1016/j.electacta.2016.03.016
Cube-shaped porous carbon (CPC) was obtained from the carbonization of MOF-5 (Zn4O(OOCC6H4COO)3) crystals and shows abundant micro/mesopores, high mechanical strength, largest surface area (2316 m2 g−1, BET method) and good electrical conductivity (a high weight ratio 98.17/1.83 of C/O). When utilized as anode material for sodium-ion batteries, the CPC presents a high overall sodium storage capacity ∼240 mAh g−1 at a current density of 100 mA g−1 after 100 cycles, and maintains a high specific capacity of 100 mAh g−1 after 5000 cycles at a current density of 3200 mA g−1. For the advantages of this unique carbon framework structure, the CPC might be a promising anode material for the application of SIBs.
Co-reporter:Mingjun Jing, Zhiying Ding, Hongshuai Hou, Yan Zhang, Guoqiang Zou, Simin Li, Xiaobo Ji
Chemical Physics Letters 2016 Volume 653() pp:30-34
Publication Date(Web):1 June 2016
DOI:10.1016/j.cplett.2016.04.057
Highlights
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Alternating voltage approach has been firstly applied to manufacture CuO.
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The as-obtained 3D-CuO is composed of single crystal nanosheets.
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Electrochemical mechanism of 3D-CuO structure formation has been proposed.
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The CuO sample displays high cyclability as anode materials for LIBs.
Co-reporter:Cheng-chi PAN, Yi-rong ZHU, Ying-chang YANG, Hong-shuai HOU, Ming-jun JING, Wei-xin SONG, Xu-ming YANG, Xiao-bo JI
Transactions of Nonferrous Metals Society of China 2016 Volume 26(Issue 5) pp:1396-1402
Publication Date(Web):May 2016
DOI:10.1016/S1003-6326(16)64244-9
Li[NixCoyMnz]O2 (0.6≤x≤0.8) cathode materials with a typical hexagonal α-NaFeO2 structure were prepared utilizing a co-precipitation method. It is found that the ratio of peak intensities of (003) to (104) observed from X-ray diffraction (XRD) increases with decreasing the Ni content or increasing the Co content. The scanning electron microscopy (SEM) images reveal that the small primary particles are agglomerated to form the secondary ones. As the Mn content increases, the primary and secondary particles become larger and the resulted particle size for the Li[Ni0.6Co0.2Mn0.2]O2 is uniformly distributed in the range of 100–300 nm. Although the initial discharge capacity of the Li/Li[NixCoyMnz]O2 cells reduces with decreasing the Ni content, the cyclic performance and rate capability are improved with higher Mn or Co content. The Li[Ni0.6Co0.2Mn0.2]O2 can deliver excellent cyclability with a capacity retention of 97.1% after 50 cycles.
Co-reporter:Hongshuai Hou;Craig E. Banks;Mingjun Jing;Yan Zhang
Advanced Materials 2015 Volume 27( Issue 47) pp:7861-7866
Publication Date(Web):
DOI:10.1002/adma.201503816
Co-reporter:Jun Chen;Weixin Song;Hongshuai Hou;Yan Zhang;Mingjun Jing;Xinnan Jia
Advanced Functional Materials 2015 Volume 25( Issue 43) pp:6793-6801
Publication Date(Web):
DOI:10.1002/adfm.201502978
Dark-colored rutile TiO2 nanorods doped by electroconducting Ti3+ have been obtained uniformly with an average diameter of ≈7 nm, and have been first utilized as anodes in lithium-ion batteries. They deliver a high reversible specific capacity of 185.7 mAh g−1 at 0.2 C (33.6 mA g−1) and maintain 92.1 mAh g−1 after 1000 cycles at an extremely high rate 50 C with an outstanding retention of 98.4%. Notably, the coulombic efficiency of Ti3+–TiO2 has been improved by approximately 10% compared with that of pristine rutile TiO2, which can be mainly attributed to its prompt electron transfer because of the introduction of Ti3+. Again the synergetic merits are noticed when the promoted electronic conductivity is combined with a shortened Li+ diffusion length resulting from the ultrafine nanorod structure, giving rise to the remarkable rate capabilities and extraordinary cycling stabilities for applications in fast and durable charge/discharge batteries. It is of great significance to incorporate Ti3+ into rutile TiO2 to exhibit particular electrochemical characteristics triggering an effective way to improve the energy storage properties.
Co-reporter:Yan Zhang, Yingchang Yang, Hongshuai Hou, Xuming Yang, Jun Chen, Mingjun Jing, Xinnan Jia and Xiaobo Ji
Journal of Materials Chemistry A 2015 vol. 3(Issue 37) pp:18944-18952
Publication Date(Web):2015/08/10
DOI:10.1039/C5TA04009D
Carbon coated anatase TiO2 hollow spheres (CCAnTHSs) are prepared through the carbon wrapping of etched amorphous TiO2 solid spheres (AmTSSs). The as-obtained CCAnTHS composite is applied as an anode material for sodium-ion batteries (SIBs) for the first time, delivering excellent cycle stability. At a high current density of 5C, a reversible capacity of 140.4 mA h g−1 remained after 500 cycles. Especially, at a 25C rate it could still reach 84.9 mA h g−1 after 80 cycles. Briefly, the sodium storage performance of CCAnTHSs are superior to these of the amorphous TiO2 solid spheres and bare anatase TiO2 hollow spheres, mainly benefitting from the advantages of a unique hollow structure with a large specific surface area and a carbon coating with high electronic conductivity.
Co-reporter:Mingjun Jing, Jufeng Wang, Hongshuai Hou, Yingchang Yang, Yan Zhang, Chengchi Pan, Jun Chen, Yirong Zhu and Xiaobo Ji
Journal of Materials Chemistry A 2015 vol. 3(Issue 32) pp:16824-16830
Publication Date(Web):14 Jul 2015
DOI:10.1039/C5TA03610K
A C quantum dot coated Mn3O4 composite (Mn3O4/Cdots) has been obtained for the first time by a green alternating voltage electrochemical approach. It is interesting to note that the morphology of Mn3O4 particles in the composite can be induced to form an octahedral structure through the introduction of C quantum dots. In particular, the as-produced Mn3O4/Cdots composite utilized as an anode material for lithium ion batteries demonstrates excellent electrochemical performances, showing an enhanced reversible discharge capacity of 934 mA h g−1 after 50 cycles at a current density of 100 mA g−1 which is almost five times as much as that of pure Mn3O4.
Co-reporter:Xuming Yang, Chao Wang, Yingchang Yang, Yan Zhang, Xinnan Jia, Jun Chen and Xiaobo Ji
Journal of Materials Chemistry A 2015 vol. 3(Issue 16) pp:8800-8807
Publication Date(Web):20 Mar 2015
DOI:10.1039/C5TA00614G
With the aim of advancing anatase TiO2 anodes for sodium ion batteries, crystalline titania nanocubes were employed and they delivered a gradually increasing capacity during the initial cycles, termed as an activation process. The number of necessary discharge–charge loops for total activation is dependent on the galvanostatic current density (about 20 cycles at 0.2 C, or 90 cycles at 1 C). A percentage of Ti3+ was detected after the activation, indicating an amount of irreversibly trapped sodium ions in the lattice. After the activation process, an excellent rate capability and outstanding cycling stability were presented. The reversible capacity reached 174, 132, and 108 mA h g−1 at rates of 1 C, 5 C, and 10 C, respectively. The capacity was sustained with a loss of less than 10% after 1000 discharge–charge cycles at a rate of 2 C or 10 C. The superior battery performance achieved by the nanocubes is related to the encircled {100} facets that are more favorable for sodium ion attachment compared to the {001} and {101} facets, as supported by first-principles calculations. From this work we can see the feasibility of optimizing electrode materials via rational surface structure construction based on theoretical calculations.
Co-reporter:Yingchang Yang, Binghan Qiao, Zhengping Wu and Xiaobo Ji
Journal of Materials Chemistry A 2015 vol. 3(Issue 10) pp:5328-5336
Publication Date(Web):19 Jan 2015
DOI:10.1039/C4TA05304D
The chemical procedure to obtain the Zintl polyanions is considerably tedious due to their own instability. We have examined cathodic corrosion for all the five group 14 elements, and polyatomic group 14 Zintl intermediates (R4N+)4M94− (M = Sn, Pb) have been electrochemically captured through cathodic corrosion, proved by in situ Raman spectroscopy. Moreover, metal powder materials are obtained through their simultaneous and/or subsequent Hofmann elimination or oxidation by water at room temperature. It is the strong covalent bonds and cubic face-centered diamond structures that determine the chemical stability of the diamond, silicon and germanium, while the metallic bonds of tin and lead make the cathodic generation of Zintl intermediates (R4N+)4M94− feasible. This work opens up new strategies to design powder materials for scientific research and industrial applications.
Co-reporter:Hongshuai Hou, Mingjun Jing, Yingchang Yang, Yan Zhang, Yirong Zhu, Weixin Song, Xuming Yang and Xiaobo Ji
Journal of Materials Chemistry A 2015 vol. 3(Issue 6) pp:2971-2977
Publication Date(Web):16 Dec 2014
DOI:10.1039/C4TA06476C
Sb porous hollow microspheres (PHMSs) were prepared by a replacement reaction employing Zn microspheres (MSs) as templates. The obtained Sb PHMSs were first applied as anode materials for sodium-ion batteries (SIBs) and showed a high reversible capacity of 617 mA h g−1 at a current density of 100 mA g−1 after 100 cycles, exhibiting a high capacity retention of 97.2%. Even at a high current density of 3200 mA g−1, the reversible capacity can also reach 312.9 mA h g−1. The superior electrochemical performance of Sb PHMSs can be attributed to the unique structural characteristic of Sb with porous and hollow structure, which can accommodate the volume change and facilitate the Na+ diffusion during the sodiation and desodiation process.
Co-reporter:Yingchang Yang, Xiaobo Ji, Mingjun Jing, Hongshuai Hou, Yirong Zhu, Laibing Fang, Xuming Yang, Qiyuan Chen and Craig E. Banks
Journal of Materials Chemistry A 2015 vol. 3(Issue 10) pp:5648-5655
Publication Date(Web):13 Feb 2015
DOI:10.1039/C4TA05611F
N-doped TiO2 nanorods decorated with carbon dots with enhanced electrical-conductivity and faster charge-transfer have been fabricated utilizing a simple hydrothermal reaction process involving TiO2 powders (P25) and NaOH in the presence of carbon dots followed by ion exchange and calcination treatments. Due to the merits of the carbon dots, doping and nanostructures, the as-designed N–TiO2/C-dots composite utilized as anode materials for lithium-ion batteries can sustain a capacity of 185 mA h g−1 with 91.6% retention even at a high rate of 10 C over 1000 cycles. It is interesting to note that the ratios of capacitive charge capacity during such high rates for the N–TiO2/C-dots composite electrodes are higher than those at low rates, which likely explains the observed excellent rate capabilities. In contrast to lithium-ion batteries, sodium-ion batteries have gained more interest in energy storage grids because of the greater abundance and lower cost of sodium-containing precursors. The as-obtained N–TiO2/C-dots composites reported here and utilized as anode materials for sodium-ion batteries exhibit excellent electrochemical performances, including substantial cycling stabilities (the capacity retention ratios after 300 cycles at 5 C is 93.6%) and remarkable rate capabilities (176 mA h g−1 at 5 C, 131 mA h g−1 at 20 C); such performances are the greatest ever reported to date over other structured TiO2 or TiO2 composite materials.
Co-reporter:Yirong Zhu, Zhibin Wu, Mingjun Jing, Hongshuai Hou, Yingchang Yang, Yan Zhang, Xuming Yang, Weixin Song, Xinnan Jia and Xiaobo Ji
Journal of Materials Chemistry A 2015 vol. 3(Issue 2) pp:866-877
Publication Date(Web):07 Nov 2014
DOI:10.1039/C4TA05507A
Carbon quantum dots (CQDs) tuned porous NiCo2O4 sphere composites are prepared for the first time via a reflux synthesis route followed by a post annealing treatment. Benefiting from the advantages of the unique porous structure with a large specific surface area, high mesoporosity and superior electronic conductivity, the as-obtained CQDs/NiCo2O4 composite electrode exhibits high specific capacitance (856 F g−1 at 1 A g−1), excellent rate capability (83.9%, 72.5% and 60.8% capacity retention rate at 20, 50 and 100 A g−1, respectively) and exceptional cycling stability (98.75% of the initial capacity retention over 10000 cycles at 5 A g−1). Furthermore, the assembled AC//CQDs/NiCo2O4 asymmetric supercapacitor manifests a high energy density (27.8 W h kg−1) at a power density of 128 W kg−1 or a high power density (10.24 kW kg−1) at the reasonable energy density of 13.1 W h kg−1 and remarkable cycling stability (101.9% of the initial capacity retention over 5000 cycles at 3 A g−1). The results above suggest a great potential of the porous CQDs/NiCo2O4 composites in the development of high-performance electrochemical energy storage devices for practical applications.
Co-reporter:Hongshuai Hou, Mingjun Jing, Zhaodong Huang, Yingchang Yang, Yan Zhang, Jun Chen, Zhibin Wu, and Xiaobo Ji
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 34) pp:19362
Publication Date(Web):August 18, 2015
DOI:10.1021/acsami.5b05509
Due to the high theoretical capacity of 946 mAh g–1, Sb2S3 can be employed as promising electrode material for sodium-ion batteries (SIBs). Herein, the sodium storage behaviors of one-dimensional (1D) Sb2S3-based materials (Sb2S3 and Sb2S3@C rods) are successfully studied for the first time, displaying good cyclability and rate capability owing to their unique morphology and structure. Specifically, the Sb2S3@C rods electrode presents greatly enhanced electrochemical properties, resulting from the introduction of thin carbon layers which can effectively alleviate the strain caused by the large volume change and simultaneously improve the conductivity of electrode during cycling. At a current density of 100 mA g–1, it delivers a high capacity of 699.1 mAh g–1 after 100 cycles, which corresponds to 95.7% of the initial reversible capacity. Even at a high current density of 3200 mA g–1, the capacity can still reach 429 mAh g–1. This achievement may be a significant exploration for develpoing novel 1D Sb-based materials or metal sulfide SIBs anodes.Keywords: anode; electrochemistry; rod; Sb2S3; sodium-ion battery
Co-reporter:Mingjun Jing, Hongshuai Hou, Craig E. Banks, Yingchang Yang, Yan Zhang, and Xiaobo Ji
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 41) pp:22741
Publication Date(Web):October 5, 2015
DOI:10.1021/acsami.5b05660
An electrochemical alternating voltage approach of producing NiCo double hydroxide (NiCoDH) layered ultrathin nanoflakes with large specific surface area (355.8 m2 g–1), remarkable specific capacitance and rate capability is presented. The obtained NiCoDH as anode for asymmetric supercapacitors shows excellent energy density of 17.5 Wh kg–1 at high power density of 10.5 kW kg–1 and cycling stability (91.2% after 10 000 cycles).Keywords: alternating voltage; asymmetric supercapacitors; electrochemical; nanoflakes; NiCo double hydroxide
Co-reporter:Yingchang Yang, Xuming Yang, Yan Zhang, Hongshuai Hou, Mingjun Jing, Yirong Zhu, Laibing Fang, Qiyuan Chen, Xiaobo Ji
Journal of Power Sources 2015 Volume 282() pp:358-367
Publication Date(Web):15 May 2015
DOI:10.1016/j.jpowsour.2015.02.071
•Hexagonal/amorphous Sb is prepared through electrochemically cathodic corrosion.•Both hexagonal and amorphous Sb electrodes show excellent Li-storage behaviors.•The hexagonal Sb exhibits enhanced Na-storage performance.Cathodic corrosion, a green electrochemical method, has been employed to obtain Sb nanomaterials utilized as anode material for lithium-ion batteries and sodium-ion batteries. Interestingly, two different corrosion mechanisms are found, coming from the impact of electrolyte, resulting in the formation of hexagonal and amorphous Sb in aqueous and organic solution, respectively. With the help of water-soluble carboxymethyl cellulose binder and the electrolyte additive fluoroethylene carbonate, both hexagonal and amorphous Sb electrodes exhibit good cycling stability when utilized as anode materials for lithium-ion batteries and sodium-ion batteries. Additionally, both the hexagonal and amorphous Sb electrodes show very good rate capability in lithium-ion batteries. Even at high current density (2000 mA g−1), the hexagonal and amorphous Sb give reversible capacities of 422 and 379 mA h g−1, respectively. Surprisingly, when used as anode materials for sodium-ion batteries, the hexagonal Sb electrode exhibits a good rate performance of 632, 625, 569, 515 and 426 mA h g−1 at a current density of 100, 200, 500, 1000, and 2000 mA g−1, respectively. However, limited rate performance is observed from the amorphous Sb electrode in case of sodium-ion battery due to the large impedance.
Co-reporter:Mingjun Jing, Chiwei Wang, Hongshuai Hou, Zhibin Wu, Yirong Zhu, Yingchang Yang, Xinnan Jia, Yan Zhang, Xiaobo Ji
Journal of Power Sources 2015 Volume 298() pp:241-248
Publication Date(Web):1 December 2015
DOI:10.1016/j.jpowsour.2015.08.039
•NiO-dots/Gh has been obtained by alternating voltage approach with one-step.•NiO quantum dots can be uniformly dispersed on the surface of few layers graphene.•The electrochemical mechanism of NiO-dots/Gh structure has been proposed.•The NiO-dots/Gh composite shows high capacity retention.•The NiO-dots/Gh displays high energy density as an asymmetric supercapacitor.A green and one-step method of electrochemical alternating voltage has been utilized to form NiO quantum dots/graphene flakes (NiO-dots/Gh) for supercapacitor applications. NiO quantum dots (∼3 nm) are uniformly deposited on few-layer graphene surfaces by oxygen functional groups on graphene surface that is naturally utilized to bridge NiO and graphene through Ni–O–C bands, which exhibits outstanding specific capacitance 1181.1 F g−1 at a current density of 2.1 A g−1 and rate behavior 66.2% at 42 A g−1 as NiO dots can be fleetly wired up to current collector through the underlying graphene two-dimensional layers. The NiO-dots/Gh composite is further undertaken in asymmetric supercapacitors with high energy density (27.3 Wh kg−1 at 1562.6 W kg−1).
Co-reporter:Yirong Zhu, Zhibin Wu, Mingjun Jing, Xinnan Jia, Xiaobo Ji
Electrochimica Acta 2015 Volume 178() pp:153-162
Publication Date(Web):1 October 2015
DOI:10.1016/j.electacta.2015.08.004
•Mesoporous NiCo2O4 hollow spheres are prepared via a soft template method.•Mesoporous NiCo2O4 hollow spheres manifest enhanced electrochemical performances.•Large BET surface area and unique hollow structure give the excellent electrochemical properties.Mesoporous NiCo2O4 hollow spheres are prepared by a soft template method utilizing a hydrothermal route. Three kinds of NiCo2O4 morphologies can be obtained, including solid sphere, hollow sphere and collapsed hollow sphere with the adjustment of the concentration of hexamethylenetetramine (HMT). Compared with solid spheres and collapsed hollow spheres, the as-prepared NiCo2O4 hollow spheres show enhanced electrochemical properties, manifesting a high specific capacitance (204.4 mAh g−1 at 2 A g−1), exceptional rate capability (62.8% capacity retention at 50 A g−1) and good cycling stability (93.2% capacity retention after 1000 cycles). Such remarkable electrochemical properties of the NiCo2O4 hollow spheres can be primarily ascribed to the high specific surface area and uniform mesoporous hollow structure that can increase the exposure of active sites available for reaction on the surface, shorten transport pathways for both electrons and ions, and alleviate the volume change during charge–discharge process. This work is significant because the unique mesoporous NiCo2O4 hollow spheres demonstrate the great potential in the development of high-performance electrode materials for supercapacitors. Additionally, this soft template method can be extended to the fabrication of other binary or even ternary metal oxides hollow micro-/nanostructure materials.
Co-reporter:Mingjun Jing, Hongshuai Hou, Yingchang Yang, Yirong Zhu, Zhibin Wu, Xiaobo Ji
Electrochimica Acta 2015 Volume 165() pp:198-205
Publication Date(Web):20 May 2015
DOI:10.1016/j.electacta.2015.03.032
•Co2MnO4/Co hydroxide chloride was obtained through alternating voltage methodology.•The Co2MnO4/Co hydroxide chloride composite showed an excellent rate behavior.•The high conductivity of Co2MnO4 can be attributed to Co ions distributed position.•An asymmetric capacitor based on Co2MnO4/Co hydroxide chloride gave a high energy density.Co2MnO4/Co hydroxide chloride (CMO/CHC) nanocomposite is firstly obtained through an electrochemically alternating voltage methodology for supercapacitor applications. The CMO/CHC electrode materials display a high specific capacitance of 779 F g−1 at 1 A g−1 and an excellent rate behavior (77.5% and 63.6% at 20 and 40 A g−1 compared with 1 A g−1, respectively). An asymmetric supercapacitor based on CMO/CHC as cathode and activated carbon (AC) as anode presents a maximum energy density of 27.8 Wh kg−1 at power density of 570.9 W kg−1.
Co-reporter:Jun Chen, Hongshuai Hou, Yingchang Yang, Weixin Song, Yan Zhang, Xuming Yang, Qing Lan, Xiaobo Ji
Electrochimica Acta 2015 Volume 164() pp:330-336
Publication Date(Web):10 May 2015
DOI:10.1016/j.electacta.2015.02.202
•Carbon-coated anatase TiO2 nanoparticles were prepared via a novel and facile in-situ methodology.•TiO2/C nanocomposites exhibite high capacity and notable rate performances as anode in lithium-ion batteries.•Such composite can offer great potential promise in large-scale energy storage applications.A novel and facile in-situ methodology has been developed to prepare well carbon-coated anatase titanium dioxide (TiO2) nanoparticles. The hydrolysis of tetrabutyl titanate has been effectively controlled in a collosol of N-methyl-2-pyrrolidone dissolved with polyvinylidene fluoride. The as-resulted carbon-dispersed TiO2 nanoparticles distributed in ranges from 20 to 30 nm in diameter have been obtained with a carbon content of 11.7 wt%. This nanocomposite utilized as anode materials in lithium-ion battery can deliver a high reversible specific capacity of 218 mAh g−1 at the current density of 0.2 C (33.5 mA g−1), and still exhibit 100 mAh g−1 at 10 C (1.68 A g−1), illustrating notable high-rate performances for the potential application in fast charge/discharge batteries.
Co-reporter:Mingjun Jing, Hongshuai Hou, Yingchang Yang, Yan Zhang, Xuming Yang, Qiyuan Chen, Xiaobo Ji
Electrochimica Acta 2015 Volume 155() pp:157-163
Publication Date(Web):10 February 2015
DOI:10.1016/j.electacta.2014.12.170
Mn3O4/graphite powder (Mn3O4/GhP) composite was successfully obtained utilizing an alternating voltage induced electrochemical method. It was found that Mn3O4 particles (∼20 nm) resulted from Mn electrodes were well dispersed on the surface of GhP. The electrochemical performances of Mn3O4/GhP material as anode for lithium-ion batteries were investigated, demonstrating high specific capacity and excellent cycling stability with a high charge-discharge capacity of 1007.4 mAh g−1 after 50 cycles at a current density of 100 mA g−1.
Co-reporter:Weixin Song, Xiaobo Ji, Jun Chen, Zhengping Wu, Yirong Zhu, Kefen Ye, Hongshuai Hou, Mingjun Jing and Craig. E. Banks
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 1) pp:159-165
Publication Date(Web):05 Nov 2014
DOI:10.1039/C4CP04649H
The ion-migration mechanism of Na3V2(PO4)2F3 is investigated in Na3V2(PO4)2F3–Li hybrid-ion batteries for the first time through a combined computational and experimental study. There are two Na sites namely Na(1) and Na(2) in Na3V2(PO4)2F3, and the Na ions at Na(2) sites with 0.5 occupation likely extract earlier to form Na2V2(PO4)2F3. The structural reorganisation is suggested to make a stable configuration of the remaining ions at the centre of Na(1) sites. After the extraction of the second Na ion, the last ion prefers to change occupation from 1 to 0.5 to occupy two Na(2) sites. The insertion of predominant Li ions also should undergo structural reorganization when the first Li ion inserts into the centre of Na(1) site theoretically forming NaLiV2(PO4)2F3, and the second ion inserts into two Na(2) sites to form NaLi2V2(PO4)2F3. More than a 0.3 Li ion insertion would take place in the applied voltage range by increasing the number of sites occupied rather than occupy the vacancy in triangular prismatic sites. An improved solution-based carbothermal reduction methodology makes Na3V2(PO4)2F3 exhibit excellent C-rate and cycling performances, of which the Li-inserted voltage is evaluated by first principles calculations.
Co-reporter:Yan Zhang, Xuli Pu, Yingchang Yang, Yirong Zhu, Hongshuai Hou, Mingjun Jing, Xuming Yang, Jun Chen and Xiaobo Ji
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 24) pp:15764-15770
Publication Date(Web):08 May 2015
DOI:10.1039/C5CP01227A
Rutile TiO2 microspheres anchored by nanoneedle clusters, as a new class of anode materials, are successfully employed for sodium-ion batteries and manifested good energy storage behavior. The initial discharge capacity of 308.8 mA h g−1 is obtained and a high reversible capacity of 121.8 mA h g−1 is maintained after 200 cycles at a current density of 0.1 C, exhibiting a high capacity retention of 83.1%. All these merits are not only ascribed to the rutile TiO2 crystal structure, but also thanks to the porous morphology of hundreds of nanoneedle clusters in favor of sodium diffusion and accommodating the strain during the sodiation and desodiation processes. Therefore, it is highly expected that rutile TiO2, as a feasible electrochemical sodium storage material, can be a new promising candidate as an anode for sodium-ion batteries.
Co-reporter:Zhibin Wu, Xuli Pu, Yirong Zhu, Mingjun Jing, Qiyuan Chen, Xinnan Jia, Xiaobo Ji
Journal of Alloys and Compounds 2015 Volume 632() pp:208-217
Publication Date(Web):25 May 2015
DOI:10.1016/j.jallcom.2015.01.147
•The effect of NaHCO3 on preparing NiCo2O4 for supercapacitor is firstly elaborated.•Foam-like NiCo2O4 was fabricated by NaHCO3 via a co-precipitation method.•The differences of NiCo2O4 prepared by NaHCO3 and NaOH are discussed.•The NiCo2O4 prepared by NaHCO3 exhibits superior capacitive behavior.•The superior electrochemical property owes to the high porosity and BET surface area.The electrochemical performances of uniform porous NiCo2O4 nanoparticles obtained through a template-free co-precipitation way were explored in details, revealing that NiCo2O4 electrode prepared by NaHCO3 has a great advantage over that fabricated by NaOH, resulting in more uniform and higher porous nanostructures, which manifests a superior specific capacitance of 726.8 F g−1 at 1 A g−1 and a better cycle stability of 72.7% retention at 5 A g−1 after 2000 cycles. The enhanced pseudocapacitive performances can mainly be ascribed to well-distributed mesoporous structure coming from the releasing of CO2 that primely prevents the agglomeration of the nanocrystals. Therefore, it can be a promising candidate to substitute the routine precipitant of NaOH for the preparation of some other binary or even ternary metal oxides for supercapacitors.
Co-reporter:Xuming Yang, Xinnan Jia and Xiaobo Ji
RSC Advances 2015 vol. 5(Issue 13) pp:9337-9340
Publication Date(Web):05 Jan 2015
DOI:10.1039/C4RA13884H
White fluorinated graphene oxide was obtained from graphene oxide under hydrothermal conditions with the coexistence of nitric and hydrofluoric acid, and characterized with an atomic percentage of 21.5 for oxygen and 14.2 for fluorine, thus ensuring good dispersibility in water.
Co-reporter:Mingjun Jing, Yingchang Yang, Yirong Zhu, Hongshuai Hou, Zhibin Wu, Qiyuan Chen and Xiaobo Ji
RSC Advances 2015 vol. 5(Issue 1) pp:177-183
Publication Date(Web):24 Nov 2014
DOI:10.1039/C4RA09869B
An alternating voltage induced method has been developed for the fabrication of porous Co3O4 sheets. The electrochemical investigation of Co3O4 sheets in LiOH, NaOH and KOH electrolytes reveals that the size of the hydrated ionic radius can have impact on its ionic conductivity, resulting in the best rate behaviour in the KOH electrolyte. Based on the results above, Co3O4 sheets were further utilized in a 2 M KOH aqueous electrolyte and exhibit a maximum specific capacitance of 288 F g−1 at a current density of 1 A g−1.
Co-reporter:Xuming Yang
The Journal of Physical Chemistry C 2015 Volume 119(Issue 8) pp:3923-3930
Publication Date(Web):February 4, 2015
DOI:10.1021/jp512289g
Single-crystalline anatase TiO2 cubes enclosed by {100} and {001} facets with tunable size, as designed based on the special three zigzag lithium diffusion paths along [100], [010], and [001] directions, were obtained through hydrothermal crystallization of TiO2 in a quaternary solution consisting of tetrabutyl titanate, acetic acid, water, and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmin][BF4]). The crystalline type and shape of as-prepared samples were confirmed by X-ray diffraction and scanning and transmission electron microscopes (XRD, SEM, and TEM). Particularly, selected area electron diffraction (SAED) patterns, high-resolution TEM images, and fast Fourier transformation (FFT) patterns of the plane and side view are given to determine the exposed {100} and {001} facets. Significantly prolonged plateaus that are very practical for power management and constant voltage output were achieved by the anatase TiO2 cubes in comparison with TiO2 nanoparticles. Besides, excellent cycle stability was presented through a long loop of discharge/charge processes with both shape and crystallinity well preserved, as ex situ SEM and XRD characterization manifested.
Co-reporter:Yingchang Yang;Binghan Qiao;Xuming Yang;Laibing Fang;Chengchi Pan;Weixin Song;Hongshuai Hou
Advanced Functional Materials 2014 Volume 24( Issue 27) pp:4349-4356
Publication Date(Web):
DOI:10.1002/adfm.201304263
Nonoxidative cathodically induced graphene (CIG) here incorporates conductive agents for Li4Ti5O12 (LTO) anode materials. The tailored LTO/CIG composite is fabricated by controlled hydrolysis of tetrabutyl titanate in the presence of nonoxidative defect-free cathodically induced graphene (CIG) and oxalic acid in a mixed solvent of ethanol and water, followed by hydrothermal reaction and a calcination treatment. Due to the introduction of defect-free graphene, the resulting LTO/CIG composite shows an excellent electrical conductivity (1.2 × 10−4 S cm−1) and Li+ diffusion coefficient (1.61 × 10−12 cm2 s−1). As a result, the tuned LTO/CIG composite exhibits outstanding electrochemical performance, including excellent cycling stability (the capacity retention ratios after 500 cycles at 0.5 C is 96.2%) and a remarkable rate capability (162 mAh g−1 at 10C, 126 mAh g−1 at 100 C). A specific energy of 272 Wh kg−1 at power of 136 W kg−1 is observed when cycling against Li-foil. Even during 36 s of charge/discharge, the specific energy of LTO/CIG composite remains at 166 Wh kg−1.
Co-reporter:Weixin Song, Xiaobo Ji, Zhengping Wu, Yirong Zhu, Yingchang Yang, Jun Chen, Mingjun Jing, Fangqian Li and Craig E. Banks
Journal of Materials Chemistry A 2014 vol. 2(Issue 15) pp:5358-5362
Publication Date(Web):05 Mar 2014
DOI:10.1039/C4TA00230J
Ion occupation and migration pathways are investigated to explore the ion-migration mechanism of Na3V2(PO4)3 with the help of first principles calculations. Na3V2(PO4)3 with a NASICON framework generates high performances as a cathode material in sodium-ion batteries.
Co-reporter:Weixin Song, Xiaobo Ji, Zhengping Wu, Yirong Zhu, Yinpeng Yao, Kaili Huangfu, Qiyuan Chen and Craig E. Banks
Journal of Materials Chemistry A 2014 vol. 2(Issue 8) pp:2571-2577
Publication Date(Web):08 Jan 2014
DOI:10.1039/C3TA14472K
Layered Na2FePO4F is utilized as a cathode in hybrid-ion batteries in order to explore the ion migration and diffusion capability. It is the first time that the ion migration mechanism and capability in a hybrid-ion battery is investigated by considering the activation energies of different migration ways. It is proposed that a rapid ion exchange of Na+ ions on the Na(2) site of the crystal structure with Li+ ions can take place to produce the NaLiFePO4F phase and is firstly confirmed by first principle calculations. Li+ ion conduction in NaLiFePO4F is prone to be two-dimensional (2D) in the interlayer plane with an essentially restricted migration along the [010] direction for interlayer transport due to the much higher energy value (4.53 eV for sodium ion and 1.63 eV for lithium ion). Additionally, the 2D ways which need lower activation energies along [100] and [001] directions and the small volume variation during redox cycling are responsible for the large diffusion capability with a maximum magnitude of 10−10 cm2 s−1.
Co-reporter:Hongshuai Hou, Mingjun Jing, Yingchang Yang, Yirong Zhu, Laibing Fang, Weixin Song, Chengchi Pan, Xuming Yang, and Xiaobo Ji
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 18) pp:16189
Publication Date(Web):August 20, 2014
DOI:10.1021/am504310k
Sodium-ion batteries (SIBs) have come up as an alternative to lithium-ion batteries (LIBs) for large-scale applications because of abundant Na storage in the earth’s crust. Antimony (Sb) hollow nanospheres (HNSs) obtained by galvanic replacement were first applied as anode materials for sodium-ion batteries and exhibited superior electrochemical performances with high reversible capacity of 622.2 mAh g–1 at a current density of 50 mA g–1 after 50 cycles, close to the theoretical capacity (660 mAh g–1); even at high current density of 1600 mA g–1, the reversible capacities can also reach 315 mAh g–1. The benefits of this unique structure can also be extended to LIBs, resulting in reversible capacity of 627.3 mAh g–1 at a current density of 100 mAh g–1 after 50 cycles, and at high current density of 1600 mA g–1, the reversible capacity is 435.6 mAhg–1. Thus, these benefits from the Sb HNSs are able to provide a robust architecture for SIBs and LIBs anodes.Keywords: anode; antimony hollow nanospheres; galvanic replacement; lithium-ion battery; sodium-ion battery
Co-reporter:Weixin Song, Xiaobo Ji, Zhengping Wu, Yingchang Yang, Zhou Zhou, Fangqian Li, Qiyuan Chen, Craig E. Banks
Journal of Power Sources 2014 Volume 256() pp:258-263
Publication Date(Web):15 June 2014
DOI:10.1016/j.jpowsour.2014.01.025
•Sodium ion-migration mechanism from/into different Na sites of Na3V2(PO4)2F3 is investigated.•Structural reorganization could contribute to three plateaus corresponding to two ions transport.•The changes in microstructure of the material can influence the ion diffusion capability.•The diffusion coefficient was firstly calculated with a magnitude of 10−12 cm2 s−1 for the Na3V2(PO4)2F3.NASICON-type Na3V2(PO4)2F3 is employed as a promising cathode for sodium-ion batteries in order to explore the ion-migration mechanism and diffusion capability. Two kinds of Na sites, namely Na(1) site and Na(2) site exist in the crystal structure per formula unit to accommodate a total of three sodium ions. The ion at Na(2) site with half occupation extracts first and inserts the last due to its high chemical potential, while the whole extraction/insertion of two ions between 1.6 and 4.6 V vs. Na+/Na can produce three plateaus in charge/discharge processes because of the reorganization of ions. The first discharge capacity of 111.6 mAh g−1 with retention of 97.6% after 50 cycles could be obtained by electrochemical testing at 0.091C. Electrochemical activation and/or structural reorganization of the system by cycling could improve the diffusion coefficient of sodium with a comparatively large magnitude of 10−12 cm2 s−1, though many influences on the resistance factors also can be attributed to the cycling process. Such work is of fundamental importance to the progression of sodium-based batteries to be fully realized and be implemented over existing Li-ion based batteries.
Co-reporter:Yirong Zhu, Xiaobo Ji, Zhengping Wu, Weixin Song, Hongshuai Hou, Zhibin Wu, Xiao He, Qiyuan Chen, Craig E. Banks
Journal of Power Sources 2014 Volume 267() pp:888-900
Publication Date(Web):1 December 2014
DOI:10.1016/j.jpowsour.2014.05.134
•Spinel NiCo2O4 was prepared by sol–gel method using three chelating agents.•The effect of different chelating agents on the electrochemical properties of the NiCo2O4 was firstly investigated.•The first-principles were used for calculation.•High specific capacitance of 1254 F g−1 at 2 A g−1 was obtained using oxalic acid as chelating agent.In this work, spinel NiCo2O4 is prepared by a facile sol–gel method with the effect of three different chelating agents including citric acid (CA), oxalic acid (OA) and ethylenediamine tetraacetic acid (EDTA) explored upon the fabrication methodology and resulting electrochemical and supercapacitor properties. The electrochemical measurements reveal that NiCo2O4 prepared using OA exhibits ultrahigh specific capacitance of 1254 F g−1 at 2 A g−1 due to the resultant high specific surface area, while NiCo2O4 prepared by EDTA exhibits the best rate capability and cycling stability owing to the subsequent large pore size. The obvious differences can be primarily ascribed to the use of the differing chelating agents which are shown, for the first time, to greatly affect the particle size, pore structure and specific surface area of the fabricated NiCo2O4. Such work is of fundamental importance and demonstrates that the tailoring of these different properties can be readily obtained through the use of differing chelating and is responsible for the observed differing electrochemical properties. Additionally, first-principles calculations were employed to investigate the electronic structure of NiCo2O4, which can help to further understand its excellent electrochemical behaviors. These results above provide a facile, cost-effective and high-performance strategy for supercapacitor electrode applications.
Co-reporter:Weixin Song, Zhengping Wu, Jun Chen, Qing Lan, Yirong Zhu, Yingchang Yang, Chengchi Pan, Hongshuai Hou, Mingjun Jing, Xiaobo Ji
Electrochimica Acta 2014 Volume 146() pp:142-150
Publication Date(Web):10 November 2014
DOI:10.1016/j.electacta.2014.09.068
NASICON Na3V2(PO4)3 and Na3V2(PO4)2F3 have restarted to be investigated electrochemically as promising cathode materials for sodium-ion batteries. Fluorine insertion by replacing partial phosphate groups in Na3V2(PO4)3 allows for new family of host lattice structure, Na3V2(PO4)2F3. Greatly, fluorine is capable to participate in structural construction to change the ions configuration which involves ions occupation, the species and amount of diverse Na sites, leading to distinct modalities for ions extraction. The inductive effects of (PO4)3− polyanion by changing electronic cloud density upon compositional atoms could be enhanced under the effects of the formed F-V bond due to its strong ionicity, which can moderate the energetics of the transition metal redox couple to generate relatively high operating potentials. The substitution of fluorine for negative-charge polyanion or anion could be effective to improve the electrochemical properties, particularly for the purpose to increase performed voltages by changing atomic environments.Fluorine participation in crystal structure construction in Na3V2(PO4)3 to form Na3V2(PO4)2F3, displays several effects on the ions configuration involving ions occupation, species and amount of diverse Na sites, and the electronic cloud density upon compositional atoms leading to distinct modalities for ions extraction as well as the operating voltages.
Co-reporter:Yirong Zhu, Zhibin Wu, Mingjun Jing, Weixin Song, Hongshuai Hou, Xuming Yang, Qiyuan Chen, Xiaobo Ji
Electrochimica Acta 2014 Volume 149() pp:144-151
Publication Date(Web):10 December 2014
DOI:10.1016/j.electacta.2014.10.064
•3D network-like mesoporous NiCo2O4 nanostructures were fabricated via a solvothermal route.•The obtained NiCo2O4 shows good electrochemical performances, especially rate capability.•Large BET surface area and abundant mesoporosity give excellent electrochemical performances.•This solvothermal method can be extended to prepare other binary or even ternary 3D metal oxides.3D network-like mesoporous NiCo2O4 nanostructures have been successfully fabricated through a solvothermal route coupled with a post annealing treatment. Benefiting from its advantages of the unique 3D network-like structures with large specific surface area (170.6 m2 g−1), abundant mesoporosity (5–10 nm) and high electronic conductivity, the as-obtained NiCo2O4 manifests high specific capacitance of 931 F g−1 at 3 A g−1, remarkable capacity retention rate of 85.2 and 72.5% at 20 and 50 A g−1 compared with 2 A g−1 and superior cycling stability of 125.2% of initial capacity retention over 1000 cycles at 3 A g−1. The excellent electrochemical performances coupled with its facile and cost-effective way will render the 3D network-like mesoporous NiCo2O4 nanostructures as attractive electrode materials for promising application in supercapacitors.
Co-reporter:Hongshuai Hou, Yingchang Yang, Yirong Zhu, Mingjun Jing, Chengchi Pan, Laibing Fang, Weixin Song, Xuming Yang, Xiaobo Ji
Electrochimica Acta 2014 Volume 146() pp:328-334
Publication Date(Web):10 November 2014
DOI:10.1016/j.electacta.2014.09.080
Sb/acetylene black (Sb/AB) composite was firstly applied as anode for sodium-ion batteries (SIBs). A great electrochemical performance of the composite was obtained when utilizing this composite for SIBs. It was found that the charge capacity can reach 473 mAh g−1 in the 70th cycle at a current density of 100 mA g−1, and we also note that the capacity contributed by Sb was about 624 mAh g−1, which is very close to its theoretical sodium storage capacity (660 mAh g−1 corresponding to a formula of Na3Sb), demonstrating the full utilization of Sb. It is interesting to see that even at a high current density of 1600 mA g−1, the capacity can still reach 281 mAh g−1.
Co-reporter:Weixin Song, Xiaobo Ji, Yinpeng Yao, Hanjun Zhu, Qiyuan Chen, Qinqin Sun and Craig E. Banks
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 7) pp:3055-3061
Publication Date(Web):07 Jan 2014
DOI:10.1039/C3CP54604G
High-energy batteries need significant cathodes which can simultaneously provide large specific capacities and high discharge plateaus. NASICON-structured Na3V2(PO4)3 (NVP) has been utilised as a promising cathode to meet this requirement and be used in the construction of high energy batteries. For a hybrid-ion battery by employing metallic lithium as an anode, NVP exhibits an initial specific capacity of 170 mA h g−1 in the voltage range of 1.6–4.8 V with a long discharge plateau around 3.7 V. Three Na(2) sites for NVP are found capable to be utilised through the application of a wide voltage window but only two of them are able to undergo ions exchange to produce a NaLi2V2(PO4)3 phase. However, a hybrid-ion migration mechanism is suggested to exist to describe the whole ion transport in which the effects of a Na-ion “barrier” results in a lowered ion diffusion rate and observed specific capacity.
Co-reporter:Weixin Song, Xiaoyu Cao, Zhengping Wu, Jun Chen, Kaili Huangfu, Xiaowen Wang, Yaliang Huang and Xiaobo Ji
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 33) pp:17681-17687
Publication Date(Web):25 Jun 2014
DOI:10.1039/C4CP01821D
Excellent C-rate and cycling performance with a high specific capacity of 117.6 mA h g−1 have been achieved on NASICON-structure Na3V2(PO4)3 sodium-ion batteries. Two different Na sites, namely Na(1) and Na(2), are reported in the open three-dimensional framework, of which the ions at the Na(2) sites should be mainly responsible for the electrochemical properties. It is vitally important and interesting to find that there are two kinds of possible ion occupation of Na ions in Na3V2(PO4)3 and the investigation of ion-extraction number is firstly explored by discussing ion occupations with the help of first-principles calculations. The ion occupation of 0.75 for all Na sites is suitable for the configuration of [Na3V2(PO4)3]2, and the two-step extraction process accompanied by structure reorganization can account for the theoretical capacity of Na3V2(PO4)3.
Co-reporter:Zhou Zhou, Yirong Zhu, Zhibin Wu, Fang Lu, Mingjun Jing and Xiaobo Ji
RSC Advances 2014 vol. 4(Issue 14) pp:6927-6932
Publication Date(Web):06 Jan 2014
DOI:10.1039/C3RA46641H
Significant enhancement in supercapacitor performances was achieved by the first fabrication of amorphous RuO2 hybrid by utilising carbon spheres as templates. The as-prepared carbon spheres (Cs)/RuO2 and reduced carbon spheres (rCs)/RuO2 composites exhibit high specific capacitances of 387 F g−1 (44.2 wt% RuO2 loading) and 614 F g−1 (72.6 wt% RuO2 loading) at a current density of 1 A g−1 at 2 mg cm−2 loading mass, showing remarkable rate capability with capacitances of 336 F g−1 and 491 F g−1 at a current density of 20 A g−1 and excellent cycling stability with capacity retention of 97.7% and 90.8% for 5000 cycles. The enhanced electrochemical performances could be attributed to the unique structure of the resulted composites as well as the high utilization of well-dispersed RuO2 nanoparticles on the carbon surface. These results demonstrate the great potential of carbon sphere-based composites in the development of high-performance electrode materials for supercapacitors.
Co-reporter:Weixin Song;Dr. Xiaobo Ji;Yirong Zhu;Hanjun Zhu;Fangqian Li;Jun Chen;Fang Lu;Yinpeng Yao;Dr. Craig. E. Banks
ChemElectroChem 2014 Volume 1( Issue 5) pp:871-876
Publication Date(Web):
DOI:10.1002/celc.201300248
Abstract
The NASICON-type Na3V2(PO4)3 (NVP) cathode material is investigated in an aqueous sodium-ion battery, which is explored by using a three-electrode system. The battery behaviors and capacitive properties of this electrode system are critically investigated by using 1 m Li2SO4, Na2SO4, and K2SO4 electrolytes, with an optimal performance found to arise in Na+-based electrolyte, which exhibits a capacitance of 209 Fg−1 at 8.5 C as well as enhanced ion diffusion. Larger, hydrated Li+ is less able to diffuse into the network of NVP, and the low conductivity and mobility leads to near noncapacitive behavior. In the case of K+-based electrolyte, NVP presents asymmetric cyclic voltammograms, owing to weak solvation and the high conductivity of K+, making the ions more easily able to form electric double-layer capacitance on the surface or pores of NVP, rather than insert into the network. The equivalent circuit based on electrochemical impedance spectroscopy result is analyzed to account for the electrochemical insertion behavior of Na+ into NVP, involving ion transfer in electrolyte solution, ion diffusion from the electrolyte to the electrode surface, as well as charge transfer and ion diffusion in the electrode solid.
Co-reporter:Weixin Song;Dr. Xiaobo Ji;Yirong Zhu;Hanjun Zhu;Fangqian Li;Jun Chen;Fang Lu;Yinpeng Yao;Dr. Craig. E. Banks
ChemElectroChem 2014 Volume 1( Issue 5) pp:
Publication Date(Web):
DOI:10.1002/celc.201400037
Abstract
The front cover artwork is provided by the group of Prof. Dr. Xiaobo Ji at Central South University (PR China). The image represents the electrochemical behaviors of NASICON Na3V2(PO4)3 utilized in Li+-, Na+-, and K+-based aqueous electrolytes. Read the full text of the article at 10.1002/celc.201300248.
Co-reporter:Yingchang Yang, Fang Lu, Zhou Zhou, Weixin Song, Qiyuan Chen, Xiaobo Ji
Electrochimica Acta 2013 Volume 113() pp:9-16
Publication Date(Web):15 December 2013
DOI:10.1016/j.electacta.2013.09.031
•Few-layer graphene sheets were prepared through electrochemically cathodic exfoliation in room temperature ionic liquids.•The mechanism of cathodic exfoliation in ionic liquids was proposed.•The derived activated graphene sheets show enhanced electrochemical properties.Electrochemically cathodic exfoliation in room temperature ionic liquids N-butyl, methylpyrrolidinium bis(trifluoromethylsulfonyl)-imide (BMPTF2N) has been developed for few-layer graphene sheets, demonstrating low levels of oxygen (2.7 at% of O) with a nearly perfect structure (ID/IG < 0.05). The mechanism of cathodic exfoliation in BMPTF2N involves the intercalation of ionic liquids cation [BMP]+ under highly negatively charge followed by graphite expansion. Porous activated graphene sheets were also obtained by activation of graphene sheets in KOH. Transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were used to characterize these graphene materials. The electrochemical performances of the graphene sheets and porous activated graphene sheets for lithium-ion battery anode materials were evaluated using cyclic voltammetry, galvanostatic charge–discharge cycling, and electrochemical impedance spectroscopy.Electrochemically cathodic exfoliation of graphite into few-layer graphene sheets in room temperature ionic liquids (RTILs) N-butyl, methylpyrrolidinium bis(trifluoromethylsulfonyl)-imide (BMPTF2N).
Co-reporter:Yingchang Yang, Xiaobo Ji, Fang Lu, Qiyuan Chen and Craig E. Banks
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 36) pp:15098-15105
Publication Date(Web):07 Aug 2013
DOI:10.1039/C3CP52808A
Porous activated graphene sheets have been for the first time exploited herein as encapsulating substrates for lithium ion battery (LIB) anodes. The as-fabricated SnO2 nanocrystals–porous activated graphene sheet (AGS) composite electrode exhibits improved electrochemical performance as an anode material for LIBs, such as better cycle performance and higher rate capability in comparison with graphene sheets, activated graphene sheets, bare SnO2 and SnO2–graphene sheet composites. The superior electrochemical performances of the designed anode can be ascribed to the porous AGS substrate, which improves the electrical conductivity of the electrode, inhibits agglomeration between particles and effectively buffers the strain from the volume variation during Li+-intercalation–de-intercalation and provides more cross-plane diffusion channels for Li+ ions. As a result, the designed anode exhibits an outstanding capacity of up to 610 mA h g−1 at a current density of 100 mA g−1 after 50 cycles and a good rate performance of 889, 747, 607, 482 and 372 mA h g−1 at a current density of 100, 200, 500, 1000, and 2000 mA g−1, respectively. This work is of importance for energy storage as it provides a new substrate for the design and implementation of next-generation LIBs exhibiting exceptional electrochemical performances.
Co-reporter:Weixin Song, Xiaobo Ji, Chengchi Pan, Yirong Zhu, Qiyuan Chen and Craig E. Banks
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 34) pp:14357-14363
Publication Date(Web):23 Jul 2013
DOI:10.1039/C3CP52308J
A NASICON-structure Na3V2(PO4)3 cathode material prepared by carbothermal reduction method is employed in a hybrid-ion battery with Li-involved electrolyte and anode. The ion-transportation mechanism is firstly investigated in this complicated system for an open three-dimensional framework Na3V2(PO4)3. Ion-exchange is greatly influenced by the standing time, for example, the 1 hour battery presents a specific capacity of 128 mA h g−1 while the 24 hour battery exhibits a value of 148 mA h g−1 with improved rate and cycling performances over existing literature reported Li-ion batteries. In the hybrid-ion system, an ion-exchange process likely takes place between the two Na(2) sites in the rhombohedral structure. NaLi2V2(PO4)3 could be produced by ion-transportation since the Na+ in the Na(1) site is stationary and the three Na(2) sites could be used to accommodate the incoming alkali ions; LixNayV2(PO4)3 would come out when the vacant site in Na(2) was occupied depending on the applied voltage range. The reported methodology and power characteristics are greater than those previously reported.
Co-reporter:Changqing Liu, Xiaobo Ji, Pingmin Zhang, Qiyuan Chen and Craig E. Banks
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 17) pp:6350-6354
Publication Date(Web):22 Mar 2013
DOI:10.1039/C3CP44171G
The chemical potential of oxygen ions at the novel oxygen pumping anode for electrowinning aluminum was manipulated by the electromotive forces to create thermodynamic stability. It is our anticipation that this newly designed anode can be applied to electrochemical metallurgy of other metals, such as the direct electrochemical reduction of TiO2 in the FFC process.
Co-reporter:Weixin Song, Xiaobo Ji, Wentao Deng, Qiyuan Chen, Chen Shen and Craig E. Banks
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 13) pp:4799-4803
Publication Date(Web):25 Feb 2013
DOI:10.1039/C3CP50516B
The structural effects of graphene on the electrochemical properties of graphene-based ultracapacitors are investigated for the first time, where the competitive impacts resulting from the edge content, specific surface area, edge/basal defects, oxygen-containing groups and metal oxides/surfactant impurities are taken into consideration, demonstrating that not one element, but all are responsible for the final behavior of graphene-based ultracapacitors. This work will be of wide importance to research producing graphene-based energy storage/generation devices.
Co-reporter:Wentao Deng, Xiaobo Ji, Maria Gómez-Mingot, Fang Lu, Qiyuan Chen and Craig E. Banks
Chemical Communications 2012 vol. 48(Issue 22) pp:2770-2772
Publication Date(Web):06 Feb 2012
DOI:10.1039/C2CC17831A
We have critically compared graphene and graphene oxide as materials for utilisation as supercapacitors indicating that the former exhibits a larger capacitance over the latter which has implications for those fabricating supercapacitors.
Co-reporter:Yingchang Yang, Xiaobo Ji, Fang Lu, Qiyuan Chen and Craig E. Banks
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 36) pp:NaN15105-15105
Publication Date(Web):2013/08/07
DOI:10.1039/C3CP52808A
Porous activated graphene sheets have been for the first time exploited herein as encapsulating substrates for lithium ion battery (LIB) anodes. The as-fabricated SnO2 nanocrystals–porous activated graphene sheet (AGS) composite electrode exhibits improved electrochemical performance as an anode material for LIBs, such as better cycle performance and higher rate capability in comparison with graphene sheets, activated graphene sheets, bare SnO2 and SnO2–graphene sheet composites. The superior electrochemical performances of the designed anode can be ascribed to the porous AGS substrate, which improves the electrical conductivity of the electrode, inhibits agglomeration between particles and effectively buffers the strain from the volume variation during Li+-intercalation–de-intercalation and provides more cross-plane diffusion channels for Li+ ions. As a result, the designed anode exhibits an outstanding capacity of up to 610 mA h g−1 at a current density of 100 mA g−1 after 50 cycles and a good rate performance of 889, 747, 607, 482 and 372 mA h g−1 at a current density of 100, 200, 500, 1000, and 2000 mA g−1, respectively. This work is of importance for energy storage as it provides a new substrate for the design and implementation of next-generation LIBs exhibiting exceptional electrochemical performances.
Co-reporter:Yan Zhang, Xuli Pu, Yingchang Yang, Yirong Zhu, Hongshuai Hou, Mingjun Jing, Xuming Yang, Jun Chen and Xiaobo Ji
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 24) pp:NaN15770-15770
Publication Date(Web):2015/05/08
DOI:10.1039/C5CP01227A
Rutile TiO2 microspheres anchored by nanoneedle clusters, as a new class of anode materials, are successfully employed for sodium-ion batteries and manifested good energy storage behavior. The initial discharge capacity of 308.8 mA h g−1 is obtained and a high reversible capacity of 121.8 mA h g−1 is maintained after 200 cycles at a current density of 0.1 C, exhibiting a high capacity retention of 83.1%. All these merits are not only ascribed to the rutile TiO2 crystal structure, but also thanks to the porous morphology of hundreds of nanoneedle clusters in favor of sodium diffusion and accommodating the strain during the sodiation and desodiation processes. Therefore, it is highly expected that rutile TiO2, as a feasible electrochemical sodium storage material, can be a new promising candidate as an anode for sodium-ion batteries.
Co-reporter:Xuming Yang, Chao Wang, Yingchang Yang, Yan Zhang, Xinnan Jia, Jun Chen and Xiaobo Ji
Journal of Materials Chemistry A 2015 - vol. 3(Issue 16) pp:NaN8807-8807
Publication Date(Web):2015/03/20
DOI:10.1039/C5TA00614G
With the aim of advancing anatase TiO2 anodes for sodium ion batteries, crystalline titania nanocubes were employed and they delivered a gradually increasing capacity during the initial cycles, termed as an activation process. The number of necessary discharge–charge loops for total activation is dependent on the galvanostatic current density (about 20 cycles at 0.2 C, or 90 cycles at 1 C). A percentage of Ti3+ was detected after the activation, indicating an amount of irreversibly trapped sodium ions in the lattice. After the activation process, an excellent rate capability and outstanding cycling stability were presented. The reversible capacity reached 174, 132, and 108 mA h g−1 at rates of 1 C, 5 C, and 10 C, respectively. The capacity was sustained with a loss of less than 10% after 1000 discharge–charge cycles at a rate of 2 C or 10 C. The superior battery performance achieved by the nanocubes is related to the encircled {100} facets that are more favorable for sodium ion attachment compared to the {001} and {101} facets, as supported by first-principles calculations. From this work we can see the feasibility of optimizing electrode materials via rational surface structure construction based on theoretical calculations.
Co-reporter:Yirong Zhu, Zhibin Wu, Mingjun Jing, Hongshuai Hou, Yingchang Yang, Yan Zhang, Xuming Yang, Weixin Song, Xinnan Jia and Xiaobo Ji
Journal of Materials Chemistry A 2015 - vol. 3(Issue 2) pp:NaN877-877
Publication Date(Web):2014/11/07
DOI:10.1039/C4TA05507A
Carbon quantum dots (CQDs) tuned porous NiCo2O4 sphere composites are prepared for the first time via a reflux synthesis route followed by a post annealing treatment. Benefiting from the advantages of the unique porous structure with a large specific surface area, high mesoporosity and superior electronic conductivity, the as-obtained CQDs/NiCo2O4 composite electrode exhibits high specific capacitance (856 F g−1 at 1 A g−1), excellent rate capability (83.9%, 72.5% and 60.8% capacity retention rate at 20, 50 and 100 A g−1, respectively) and exceptional cycling stability (98.75% of the initial capacity retention over 10000 cycles at 5 A g−1). Furthermore, the assembled AC//CQDs/NiCo2O4 asymmetric supercapacitor manifests a high energy density (27.8 W h kg−1) at a power density of 128 W kg−1 or a high power density (10.24 kW kg−1) at the reasonable energy density of 13.1 W h kg−1 and remarkable cycling stability (101.9% of the initial capacity retention over 5000 cycles at 3 A g−1). The results above suggest a great potential of the porous CQDs/NiCo2O4 composites in the development of high-performance electrochemical energy storage devices for practical applications.
Co-reporter:Changqing Liu, Xiaobo Ji, Pingmin Zhang, Qiyuan Chen and Craig E. Banks
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 17) pp:NaN6354-6354
Publication Date(Web):2013/03/22
DOI:10.1039/C3CP44171G
The chemical potential of oxygen ions at the novel oxygen pumping anode for electrowinning aluminum was manipulated by the electromotive forces to create thermodynamic stability. It is our anticipation that this newly designed anode can be applied to electrochemical metallurgy of other metals, such as the direct electrochemical reduction of TiO2 in the FFC process.
Co-reporter:Weixin Song, Xiaobo Ji, Chengchi Pan, Yirong Zhu, Qiyuan Chen and Craig E. Banks
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 34) pp:NaN14363-14363
Publication Date(Web):2013/07/23
DOI:10.1039/C3CP52308J
A NASICON-structure Na3V2(PO4)3 cathode material prepared by carbothermal reduction method is employed in a hybrid-ion battery with Li-involved electrolyte and anode. The ion-transportation mechanism is firstly investigated in this complicated system for an open three-dimensional framework Na3V2(PO4)3. Ion-exchange is greatly influenced by the standing time, for example, the 1 hour battery presents a specific capacity of 128 mA h g−1 while the 24 hour battery exhibits a value of 148 mA h g−1 with improved rate and cycling performances over existing literature reported Li-ion batteries. In the hybrid-ion system, an ion-exchange process likely takes place between the two Na(2) sites in the rhombohedral structure. NaLi2V2(PO4)3 could be produced by ion-transportation since the Na+ in the Na(1) site is stationary and the three Na(2) sites could be used to accommodate the incoming alkali ions; LixNayV2(PO4)3 would come out when the vacant site in Na(2) was occupied depending on the applied voltage range. The reported methodology and power characteristics are greater than those previously reported.
Co-reporter:Weixin Song, Xiaobo Ji, Wentao Deng, Qiyuan Chen, Chen Shen and Craig E. Banks
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 13) pp:NaN4803-4803
Publication Date(Web):2013/02/25
DOI:10.1039/C3CP50516B
The structural effects of graphene on the electrochemical properties of graphene-based ultracapacitors are investigated for the first time, where the competitive impacts resulting from the edge content, specific surface area, edge/basal defects, oxygen-containing groups and metal oxides/surfactant impurities are taken into consideration, demonstrating that not one element, but all are responsible for the final behavior of graphene-based ultracapacitors. This work will be of wide importance to research producing graphene-based energy storage/generation devices.
Co-reporter:Weixin Song, Xiaoyu Cao, Zhengping Wu, Jun Chen, Kaili Huangfu, Xiaowen Wang, Yaliang Huang and Xiaobo Ji
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 33) pp:NaN17687-17687
Publication Date(Web):2014/06/25
DOI:10.1039/C4CP01821D
Excellent C-rate and cycling performance with a high specific capacity of 117.6 mA h g−1 have been achieved on NASICON-structure Na3V2(PO4)3 sodium-ion batteries. Two different Na sites, namely Na(1) and Na(2), are reported in the open three-dimensional framework, of which the ions at the Na(2) sites should be mainly responsible for the electrochemical properties. It is vitally important and interesting to find that there are two kinds of possible ion occupation of Na ions in Na3V2(PO4)3 and the investigation of ion-extraction number is firstly explored by discussing ion occupations with the help of first-principles calculations. The ion occupation of 0.75 for all Na sites is suitable for the configuration of [Na3V2(PO4)3]2, and the two-step extraction process accompanied by structure reorganization can account for the theoretical capacity of Na3V2(PO4)3.
Co-reporter:Weixin Song, Xiaobo Ji, Yinpeng Yao, Hanjun Zhu, Qiyuan Chen, Qinqin Sun and Craig E. Banks
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 7) pp:NaN3061-3061
Publication Date(Web):2014/01/07
DOI:10.1039/C3CP54604G
High-energy batteries need significant cathodes which can simultaneously provide large specific capacities and high discharge plateaus. NASICON-structured Na3V2(PO4)3 (NVP) has been utilised as a promising cathode to meet this requirement and be used in the construction of high energy batteries. For a hybrid-ion battery by employing metallic lithium as an anode, NVP exhibits an initial specific capacity of 170 mA h g−1 in the voltage range of 1.6–4.8 V with a long discharge plateau around 3.7 V. Three Na(2) sites for NVP are found capable to be utilised through the application of a wide voltage window but only two of them are able to undergo ions exchange to produce a NaLi2V2(PO4)3 phase. However, a hybrid-ion migration mechanism is suggested to exist to describe the whole ion transport in which the effects of a Na-ion “barrier” results in a lowered ion diffusion rate and observed specific capacity.
Co-reporter:Weixin Song, Xiaobo Ji, Jun Chen, Zhengping Wu, Yirong Zhu, Kefen Ye, Hongshuai Hou, Mingjun Jing and Craig. E. Banks
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 1) pp:NaN165-165
Publication Date(Web):2014/11/05
DOI:10.1039/C4CP04649H
The ion-migration mechanism of Na3V2(PO4)2F3 is investigated in Na3V2(PO4)2F3–Li hybrid-ion batteries for the first time through a combined computational and experimental study. There are two Na sites namely Na(1) and Na(2) in Na3V2(PO4)2F3, and the Na ions at Na(2) sites with 0.5 occupation likely extract earlier to form Na2V2(PO4)2F3. The structural reorganisation is suggested to make a stable configuration of the remaining ions at the centre of Na(1) sites. After the extraction of the second Na ion, the last ion prefers to change occupation from 1 to 0.5 to occupy two Na(2) sites. The insertion of predominant Li ions also should undergo structural reorganization when the first Li ion inserts into the centre of Na(1) site theoretically forming NaLiV2(PO4)2F3, and the second ion inserts into two Na(2) sites to form NaLi2V2(PO4)2F3. More than a 0.3 Li ion insertion would take place in the applied voltage range by increasing the number of sites occupied rather than occupy the vacancy in triangular prismatic sites. An improved solution-based carbothermal reduction methodology makes Na3V2(PO4)2F3 exhibit excellent C-rate and cycling performances, of which the Li-inserted voltage is evaluated by first principles calculations.
Co-reporter:Weixin Song, Xiaobo Ji, Zhengping Wu, Yirong Zhu, Yingchang Yang, Jun Chen, Mingjun Jing, Fangqian Li and Craig E. Banks
Journal of Materials Chemistry A 2014 - vol. 2(Issue 15) pp:NaN5362-5362
Publication Date(Web):2014/03/05
DOI:10.1039/C4TA00230J
Ion occupation and migration pathways are investigated to explore the ion-migration mechanism of Na3V2(PO4)3 with the help of first principles calculations. Na3V2(PO4)3 with a NASICON framework generates high performances as a cathode material in sodium-ion batteries.
Co-reporter:Weixin Song, Xiaobo Ji, Zhengping Wu, Yirong Zhu, Yinpeng Yao, Kaili Huangfu, Qiyuan Chen and Craig E. Banks
Journal of Materials Chemistry A 2014 - vol. 2(Issue 8) pp:NaN2577-2577
Publication Date(Web):2014/01/08
DOI:10.1039/C3TA14472K
Layered Na2FePO4F is utilized as a cathode in hybrid-ion batteries in order to explore the ion migration and diffusion capability. It is the first time that the ion migration mechanism and capability in a hybrid-ion battery is investigated by considering the activation energies of different migration ways. It is proposed that a rapid ion exchange of Na+ ions on the Na(2) site of the crystal structure with Li+ ions can take place to produce the NaLiFePO4F phase and is firstly confirmed by first principle calculations. Li+ ion conduction in NaLiFePO4F is prone to be two-dimensional (2D) in the interlayer plane with an essentially restricted migration along the [010] direction for interlayer transport due to the much higher energy value (4.53 eV for sodium ion and 1.63 eV for lithium ion). Additionally, the 2D ways which need lower activation energies along [100] and [001] directions and the small volume variation during redox cycling are responsible for the large diffusion capability with a maximum magnitude of 10−10 cm2 s−1.
Co-reporter:Yan Zhang, Yingchang Yang, Hongshuai Hou, Xuming Yang, Jun Chen, Mingjun Jing, Xinnan Jia and Xiaobo Ji
Journal of Materials Chemistry A 2015 - vol. 3(Issue 37) pp:NaN18952-18952
Publication Date(Web):2015/08/10
DOI:10.1039/C5TA04009D
Carbon coated anatase TiO2 hollow spheres (CCAnTHSs) are prepared through the carbon wrapping of etched amorphous TiO2 solid spheres (AmTSSs). The as-obtained CCAnTHS composite is applied as an anode material for sodium-ion batteries (SIBs) for the first time, delivering excellent cycle stability. At a high current density of 5C, a reversible capacity of 140.4 mA h g−1 remained after 500 cycles. Especially, at a 25C rate it could still reach 84.9 mA h g−1 after 80 cycles. Briefly, the sodium storage performance of CCAnTHSs are superior to these of the amorphous TiO2 solid spheres and bare anatase TiO2 hollow spheres, mainly benefitting from the advantages of a unique hollow structure with a large specific surface area and a carbon coating with high electronic conductivity.
Co-reporter:Mingjun Jing, Jufeng Wang, Hongshuai Hou, Yingchang Yang, Yan Zhang, Chengchi Pan, Jun Chen, Yirong Zhu and Xiaobo Ji
Journal of Materials Chemistry A 2015 - vol. 3(Issue 32) pp:NaN16830-16830
Publication Date(Web):2015/07/14
DOI:10.1039/C5TA03610K
A C quantum dot coated Mn3O4 composite (Mn3O4/Cdots) has been obtained for the first time by a green alternating voltage electrochemical approach. It is interesting to note that the morphology of Mn3O4 particles in the composite can be induced to form an octahedral structure through the introduction of C quantum dots. In particular, the as-produced Mn3O4/Cdots composite utilized as an anode material for lithium ion batteries demonstrates excellent electrochemical performances, showing an enhanced reversible discharge capacity of 934 mA h g−1 after 50 cycles at a current density of 100 mA g−1 which is almost five times as much as that of pure Mn3O4.
Co-reporter:Yingchang Yang, Xiaobo Ji, Mingjun Jing, Hongshuai Hou, Yirong Zhu, Laibing Fang, Xuming Yang, Qiyuan Chen and Craig E. Banks
Journal of Materials Chemistry A 2015 - vol. 3(Issue 10) pp:NaN5655-5655
Publication Date(Web):2015/02/13
DOI:10.1039/C4TA05611F
N-doped TiO2 nanorods decorated with carbon dots with enhanced electrical-conductivity and faster charge-transfer have been fabricated utilizing a simple hydrothermal reaction process involving TiO2 powders (P25) and NaOH in the presence of carbon dots followed by ion exchange and calcination treatments. Due to the merits of the carbon dots, doping and nanostructures, the as-designed N–TiO2/C-dots composite utilized as anode materials for lithium-ion batteries can sustain a capacity of 185 mA h g−1 with 91.6% retention even at a high rate of 10 C over 1000 cycles. It is interesting to note that the ratios of capacitive charge capacity during such high rates for the N–TiO2/C-dots composite electrodes are higher than those at low rates, which likely explains the observed excellent rate capabilities. In contrast to lithium-ion batteries, sodium-ion batteries have gained more interest in energy storage grids because of the greater abundance and lower cost of sodium-containing precursors. The as-obtained N–TiO2/C-dots composites reported here and utilized as anode materials for sodium-ion batteries exhibit excellent electrochemical performances, including substantial cycling stabilities (the capacity retention ratios after 300 cycles at 5 C is 93.6%) and remarkable rate capabilities (176 mA h g−1 at 5 C, 131 mA h g−1 at 20 C); such performances are the greatest ever reported to date over other structured TiO2 or TiO2 composite materials.
Co-reporter:Yingchang Yang, Binghan Qiao, Zhengping Wu and Xiaobo Ji
Journal of Materials Chemistry A 2015 - vol. 3(Issue 10) pp:NaN5336-5336
Publication Date(Web):2015/01/19
DOI:10.1039/C4TA05304D
The chemical procedure to obtain the Zintl polyanions is considerably tedious due to their own instability. We have examined cathodic corrosion for all the five group 14 elements, and polyatomic group 14 Zintl intermediates (R4N+)4M94− (M = Sn, Pb) have been electrochemically captured through cathodic corrosion, proved by in situ Raman spectroscopy. Moreover, metal powder materials are obtained through their simultaneous and/or subsequent Hofmann elimination or oxidation by water at room temperature. It is the strong covalent bonds and cubic face-centered diamond structures that determine the chemical stability of the diamond, silicon and germanium, while the metallic bonds of tin and lead make the cathodic generation of Zintl intermediates (R4N+)4M94− feasible. This work opens up new strategies to design powder materials for scientific research and industrial applications.
Co-reporter:Hongshuai Hou, Mingjun Jing, Yingchang Yang, Yan Zhang, Yirong Zhu, Weixin Song, Xuming Yang and Xiaobo Ji
Journal of Materials Chemistry A 2015 - vol. 3(Issue 6) pp:NaN2977-2977
Publication Date(Web):2014/12/16
DOI:10.1039/C4TA06476C
Sb porous hollow microspheres (PHMSs) were prepared by a replacement reaction employing Zn microspheres (MSs) as templates. The obtained Sb PHMSs were first applied as anode materials for sodium-ion batteries (SIBs) and showed a high reversible capacity of 617 mA h g−1 at a current density of 100 mA g−1 after 100 cycles, exhibiting a high capacity retention of 97.2%. Even at a high current density of 3200 mA g−1, the reversible capacity can also reach 312.9 mA h g−1. The superior electrochemical performance of Sb PHMSs can be attributed to the unique structural characteristic of Sb with porous and hollow structure, which can accommodate the volume change and facilitate the Na+ diffusion during the sodiation and desodiation process.
Co-reporter:Jun Chen, Guoqiang Zou, Hongshuai Hou, Yan Zhang, Zhaodong Huang and Xiaobo Ji
Journal of Materials Chemistry A 2016 - vol. 4(Issue 32) pp:NaN12601-12601
Publication Date(Web):2016/07/19
DOI:10.1039/C6TA03505A
Hierarchical anatase TiO2 homogeneously tuned by using carbon through Ti–C bonds has been designed, exploiting carbon quantum dots as uniform carbon additives and functionalization inducers for structure tailoring and surface modification. The fabricated pinecone-like structure constructed by ultrafine subunits presents a highly increased surface area (202.4 m2 g−1) and abundant mesopores. Surface bonded carbon significantly boosts its electronic conductivity derived from both the conductive carbon and accompanied oxygen vacancies. When utilized in sodium-ion batteries, it delivers a high reversible specific capacity of 264.1 mA h g−1 at a rate of 0.1C (33.6 mA g−1) and still maintains 108.2 mA h g−1 even after 2000 cycles at 10C with a retention of 94.7% outstandingly. Notably, its Na+ intercalation pseudocapacitive behavior is enhanced by the modulated TiO2/carbon interfaces, facilitating a fast (de-)sodiation process. Combining the elaborate hierarchical structure with the unique surface composition, synergetic merits are noticed when the promoted kinetics, improved electronic conductivity, increased electrolyte penetration areas and shortened Na+ diffusion length are achieved simultaneously, giving rise to remarkable high-rate capabilities and long-term cyclability.
Co-reporter:Wentao Deng, Xiaobo Ji, Maria Gómez-Mingot, Fang Lu, Qiyuan Chen and Craig E. Banks
Chemical Communications 2012 - vol. 48(Issue 22) pp:NaN2772-2772
Publication Date(Web):2012/02/06
DOI:10.1039/C2CC17831A
We have critically compared graphene and graphene oxide as materials for utilisation as supercapacitors indicating that the former exhibits a larger capacitance over the latter which has implications for those fabricating supercapacitors.
