溶胶-凝胶法制备LiFePO_4/C及其性能优化  

Optimization of electrochemical properties of LiFePO_4/C synthesized by sol-gel method

作　　者：顾佳林[1] 陈金伟[1] 李安琪[1] 刘效疆[2] 王瑞林[1] 

机构地区：[1]四川大学材料科学与工程学院,四川成都610064 [2]中国工程物理研究院电子工程研究所,四川绵阳621900

出　　处：《电源技术》2013年第6期940-943,共4页Chinese Journal of Power Sources

基　　金：高等学校博士学科点专项科研基金(2011018-1110003);成都市科技局攻关计划(10GGYB380GX-023;10GGYB828GX023);中物院-川大联合创新基金(XTCX2011001)

摘　　要：以柠檬酸为碳源和络合剂,通过溶胶-凝胶法制备LiFePO4/C正极材料,研究了柠檬酸与氢氧化锂的加入比例对LiFePO4/C结构、形貌及电化学性能的影响。结果表明:柠檬酸的加入量明显地影响着LiFePO4/C的微观形貌,当柠檬酸与氢氧化锂的摩尔比例为1.5∶1时,LiFePO4/C表面呈现出有利于电子和Li+传导的疏松的孔状结构,对应地具有最佳的充放电性能。同时,考虑到碳包覆的影响,对以该比例制得的LiFePO4/C为正极材料的扣式电池中乙炔黑的加入量进行了优化。当正极片质量配比为LiFePO4/C∶PVDF∶乙炔黑=80∶15∶5时,充放电性能最好。此条件下制得的扣式电池在0.1 C和0.2 C充放电时,首次放电比容量分别为144.4、123.6 mAh/g,循环10次后容量保持率均在95%以上。LiFePO4/C composite cathode materials were prepared by sol-gel method with citric acid as carbon source and complexing agent. Structure, morphology and electrochemical properties of the cathode materials with different molar ratios of citric to lithium hydroxide were studied. The results show that, the molar ratios of citric to lithium hydroxide influence the morphology of the cathode materials obviously. Especially, when the molar ratio is 1.5 ： 1, it displays porous structure on the particle surface which is beneficial to transfer electrons and Li-ions, and also gains the highest charge/discharge capacity. Considering the existence of carbon, the amount of acetylene black in process of coin cell is also optimized. When electrode contains 80% of LiFePO4/C, 15% of PVDF, and 5% of acetylene black, the cell gains the highest charge/discharge capacity. The initial discharge specific capacities of the cells reaches 144.4 mAh/g at 0.1 C, and 123.6 mAh/g at 0.2 C in this condition, and the capacity retentions of both conditions are over 95% after 10= cycle.

关 键 词：锂离子电池 LIFEPO4 C 溶胶-凝胶法 柠檬酸 乙炔黑 

分 类 号：TM914[电气工程—电力电子与电力传动]