低成本动力锂离子电池磷酸铁锂正极材料的合成及性能

磷酸铁锂作为动力锂离子电池的正极材料的首选,正逐渐走向市场.以廉价的Li₃PO₄,FePO₄,Fe粉为原料,一步合成了LiFePO₄/C正极材料,系统研究了葡萄糖、蔗糖和柠檬酸三种不同的碳源对磷酸铁锂性能的影响.采用TG-DTA,XRD,SEM,TEM等手段对产物进行了表征,并研究了其电化学性能.实验结果表明,以葡萄糖为碳源的LiFePO₄/C性能最好,样品颗粒呈球形,表面光滑,分散性好,颗粒表面包覆有2 nm厚的石墨碳层,颗粒之间有碳纤维连接.该样品在0.1 C充放电时首周放电容量达到162.1 mAh/g,20周之后仍然保持在155 mAh/g,显示出良好的循环性能.

Synthesis and properties of LiFePO4 materials for powered Li-ion batteries with low cost

LiFePO₄ is being used as the cathode material for powered Li-ion batteries of electric vehicles.In this work,a carbon-coated LiFePO₄ was synthesized by thermal decomposition method using Li₃PO₄,FePO₄ and Fe as the raw materials.Glucose,sucrose and citric acid used as the carbon sources have been investigated.Experimental results showed that the sample with the glucose as the carbon source presented the excellent electrochemical properties.LiFePO₄/C particles were sphere and evenly distributed with the size of 300～800nm,the surface of particles was coated by carbon and particles were linked together by carbon fiber.The first discharge capacity reached 162.1 mAh/g and remained over 155 mAh/g after 20 cycles.Our research lowered the cost of Li-ion batteries and provided a feasible application in Li-ion batteries for industrial production.