锂电池中低成本碳包覆磷酸铁锂正极材料的合成及其性能

Synthesis and Properties of Low Cost LiFePO_4/C Cathode Material for Li-ion Battery

磷酸铁锂作为动力锂离子电池的正极材料正逐渐走向市场.以Li3PO4,FePO4,Fe粉以及乙醇为原料,采用高温热分解方法成功地制得乙醇碳包覆的LiFePO4正极材料.实验结果表明,该LiFePO4/C材料颗粒均匀,分散性好,粒径大约在200nm～1μm之间,颗粒表面被碳包覆,颗粒之间由碳纤维连接.该正极材料首次放电容量达137mAh·g-1,首次充放电库仑效率在95%以上,50次循环后,放电容量基本不衰减,显示出良好的循环稳定性和可逆性.本研究降低了锂离子电池的生产成本,显示了良好的工业化应用前景.

LiFePO4 is being used as the cathode material for Li-ion batteries of electric vehicle （EV） because of low cost and high safety. In this work, a carbon-coated LiFePO4 was synthesized by a thermal decomposition method using Li3PO4, FePO4, Fe powder and ethanol as the raw materials. Experimental results showed that LiFePO4/C particles were evenly distributed with the sizes of 200 nm- 1 μm, the surface of particles was coated by carbon, and the particles were linked together by carbon fibers. The first discharge capacity of sample reached 137 mAh.g^-1 and the first columbic efficiency was over 95%. After 50 cycles, the discharge capacity still remained unchanged, which indicated the good cycle capability and reversibility. Our research lowered the cost of Li-ion batteries and provided a feasible application in Li-ion batteries for industrial production.