添加γ-氨丙基三乙氧基硅烷的LiFePO_4/C的制备及性能

Preparation and properties of LiFePO_4/C added with γ-aminopropyl triethoxysilance

采用固-液相球磨法,在原料中加入γ-氨丙基三乙氧基硅烷(KH—550)为分散剂和掺杂剂,制备了LiFePO4/C正极材料。用XRD,SEM及电化学综合测试仪研究了所制材料的结构、表观形貌及电化学性能。结果表明:制备的LiFePO4为标准的橄榄石型结构,添加KH—550后,颗粒无团聚现象,材料的倍率性能和循环性能明显改善:在0.1 C时,首次放电比容量达到157.9 mAh/g,,比未添加KH—550样品高出6.5 mAh/g,,5 C倍率放电时,容量保持在110.3 mAh/g。经过100次循环后,容量保持率为97.3%,比未添加KH—550样品高出6.4%。

LiFePO4/C cathode was synthesized by solid-liquid milling method using γ-aminopropyl triethoxysilance（KH—550）as dispersant and dopant.The structure,morphology and electrochemical performance of LiFePO4/C were characterized by XRD,SEM and electrochemical comprehensive test system.The results show that LiFePO4 is standard olivine-type structure,and after addition of KH—550,the LiFePO4/C has better particle dispersion without agglomeration.The rate and cycle performance of LiFePO4/C both have an excellent improvement： the initial discharge capacity at 0.1 C is 157.9 mAh/g,which is 6.5 mAh/g higher than that of LiFePO4/C without adding of KH—550,and the initial discharge capacity still is 110.3 mAh/g at 5 C.After 100 times cycle,the discharge capacity is 97.3% of initial capacity,which is 6.4% more than LiFePO4/C without addition of KH—550.