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Abstract: A voltage-sensitive separator is prepared simply by impregnating electroactive poly(3-decylthiophene) (P3DT) polymer into a commercial porous separator and tested for a self-actuating control of overcharge voltage of LiFePO4/C lithium-ion batteries. The experimental results demonstrate that this type of separator can be reversibly p-doped and dedoped to maintain the cell''s voltage at a safe value of ≤4V even at high rate overcharge of 3C current, effectively protecting the batteries from voltage runaway. Since this P3DT-modified separator has no obvious negative impact on the normal charge–discharge performance of the batteries, it may be adopted for practical application in commercial lithium ion batteries. [Copyright &y& Elsevier]

Abstract: FeSi6/graphite composite was prepared by mechanical ball milling. The FeSi6 alloy particles consist of an electrochemically active silicon phase and inactive phases FeSi2, distributed uniformly in the graphite matrix. The composite anode offers a large reversible capacity (about 800mAhg−1) and good cycleability, due to the buffering effect of the inactive FeSi2 phase and graphite layers on the volumetric changes of Si phase during lithium–Si alloying reaction. Since FeSi6 alloy is a low-cost industrial material, this alloy compound provides a possible alternative for development of high capacity lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: A carbon-coated nanocrystalline LiFePO4 cathode material was synthesized by pyrolysis of polyacrylate precursor containing Li+, Fe3+ and PO4 −. The powder X-ray diffraction (XRD) and high-resolution TEM micrographs revealed that the LiFePO4/C composite as prepared has a core-shell structure with pure olivine LiFePO4 crystallites as cores and intimate carbon coating as a shell layer. Between the composite particulates, there exists a carbon matrix binding the nanocrystallites together into micrometer particles. The electrochemical measurements demonstrated that the LiFePO4/C composite with an appropriate carbon content can deliver a very high discharge capacity of 157mAhg−1 (>92% of the theoretical capacity of LiFePO4) with 95% of its initial capacity after 30 cycles. Since this preparation method uses less costly materials and operates in mild synthetic conditions, it may provide a feasible way for industrial production of the LiFePO4/C cathode materials for the lithium-ion batteries. [Copyright &y& Elsevier]