Monocrystalline porous iron oxide particles with tunable size have been synthesized by adjusting pH of the FeCl3 aqueous solution through a hydrothermal process. The size of the porous iron oxide α-Fe2O3 particles could be tuned from 925 nm to 43 nm when pH of the FeCl3 aqueous solutions increased from 1.8 to 9.3. N2 absorption investigation indicated that the α-Fe2O3 particles with size of 925 nm are mesopore/macropore-dominated, while the α-Fe2O3 particles with size of 43 nm are microporous. The mesopore/macropore-dominated α-Fe2O3 particles exhibit better rate capability than the microporous α-Fe2O3 particles, indicating promising candidate as anode materials for high energy-density lithium-ion batteries.Highlights► Monocrystalline porous α-Fe2O3 particles with tunable size have been synthesized. ► pH of the aqueous solution has a strong effect on size of the α-Fe2O3 particles. ► Mesoporous α-Fe2O3 displays better electrochemical property than microporous α-Fe2O3.

In this study, the graphite/polymer composite bipolar plate was manufactured by a bulk-molding compound process. Low-cost novolac epoxy was chosen to compound with natural graphite and black carbon. The electrical properties and mechanical properties of composite bipolar plate were studied. The aging behavior was characterized according to the changes in property before and after the immersion test. The results show that the composite bipolar plates have good corrosion resistibility in the simulated solution of 0.005 mol L−1 H2SO4 + 2 × 10−6 mol L−1 HF. TGA result shows that the novolac epoxy/NG composite has excellent thermal stability. The optimum processing conditions for preparing composite bipolar plate are: resin content about 15 wt.%; molding pressure 200 MPa; curing temperature 180 °C; graphite particle size −200 mesh. Under the optimum conditions, the composite bipolar plates have been produced, the electrical conductivity can attain to 120 S/cm and flexural strength is higher than 38 MPa.

In this paper, natural flake graphite was treated by mild oxidation and carbon coating techniques. The effects of modification on the crystal structure, morphology and electrochemical performance were investigated. The results indicate that the interlayer distance of flake graphite increases, and shape operation of graphite particle occurs after modification. Electrochemical measurements show that the initial columbic efficiency of graphite anode material increases from 73.4% to 89.7% after mild oxidation treatment, and the reversible capacity of composite that coated with pyrolytic carbon is about 359.7mAh g-1, and its cycling performance is improved. The modification results in a decrease of electrochemical polarization of graphite anode and an increase of the diffusion coefficient of lithium in graphite. Thus, the rate capacity is improved.