一维电极活性材料LiFePO_4的制备及其电化学性能研究

Preparation of one dimensional electrode active material LiFePO_4 and its electrochemical properties

以FePO_4、Li_2CO_3为原料,蔗糖为碳源物质,草酸为还原剂及螯合剂,聚乙烯吡咯烷酮(PVP)为增稠剂,通过静电纺丝技术制备了一维纳米结构的LiFePO_4材料。制备材料表现出较好的倍率特性,10.0C高倍率下可保持约55%的可逆放电比容量。该材料亦表现出良好的低温放电性能,–30℃下可保持47%的初始容量。这些性能的发挥主要得益于其优秀的一维纳米线结构。该结构可以有效降低Li+在充放电过程中的扩散距离,利于材料的电化学性能的充分发挥。

The LiFePO4/C composite was synthesized by electrospinning method. FePO4 and Li2CO3 were chosen as the raw materials, sucrose as the carbon sources and oxalic acid as the chelating and reduction agent, PVP as the thickener. The LiFePO4 nano fiber shows high rate performance（retained 55% reversible discharge capacity even at 10.0C rate）, and high low-temperature discharge capability（retained 47% initial capacity at –30 ℃）. Those outstanding performances are obtained as the excellent structure-nano fiber. It reduces the path lengths of the Li＋ during the charge/discharge process, and the polarization of the LiFePO4.