石墨形貌对锂离子电池倍率性能的影响

Impacts of graphite morphology on rate performance of Li-ion battery

选取了4类不同形貌的人造石墨样品作为锂离子动力电池的负极材料,结合XRD、SEM等手段对石墨的结构、形貌和物理性能进行分析,并组装圆柱形磷酸铁锂(LiFePO_4)动力锂离子电池进行电化学性能测试,综合考察石墨形貌对动力电池倍率性能的影响。采用二次造粒型石墨负极的LiFePO_4电池表现出较好的倍率和循环性能,6C倍率放电保持率达105.9%,6C放电温升32℃,6C循环200次,容量保持率91.06%。

Four types of artificial graphite samples with different morphology were utilized as negative electrode materials for Li-ion batteries. Crystalline structure, morphology and physical properties of graphite samples were characterized by XRD, SEM and other instruments. The Electrochemical performance of cylindrical lithium iron phosphate（ LiFePO4 ） power Li-ion battery was tested. The influence of morphology of graphite on power battery rate performance was investigated. LiFePO4/graphite with secondary granulation structure batteries exhibited better performance in rate and cycle tests. Capacity retention and temperature elevation at 6 C high-rate were 105.9% and 32 ℃ ,capacity retention was 91.06% after 200 cycles at 6 C rate.