复合负极锂离子电池的低温充电性能

Low temperature charging performance of composite anode Li-ion battery

相比人造石墨,软碳具有更好的低温循环性能。考察软碳与人造石墨复合负极材料在三元材料/人造石墨-软碳体系中的低温循环性能。使用软碳与人造石墨(质量比3∶7)复合材料的电芯,在-20℃下以1.0 C于2.5~4.2 V循环25次,放电容量恢复至初始容量的48.20%,高于使用人造石墨的34.73%。分析低温充电曲线可知,使用软碳与人造石墨复合材料的电芯在低温充电过程中,Li+优先嵌入软碳材料中。软碳作为低温大倍率充电的主要载体,降低了人造石墨析锂的风险。

Soft carbon had better low temperature cycle performance compared with artificial graphite.The low temperature cycle performance of soft carbon and artificial graphite composite anode materials in ternary material/artificial graphite-soft carbon system was investigated.The discharge capacity of the cell using soft carbon and artificial graphite(mass ratio was 3∶7)composite materials recovered to 48.20%of initial capacity cycled 25 times at 1.0 C in 2.5-4.2 V at-20℃,which was higher than using artificial graphite(34.73%).By analyzing the low temperature charge curve,it showed that in the process of low temperature charging of the cell using soft carbon and artificial graphite composite materials,Li+was preferentially embedded in the soft carbon material.Soft carbon was the main carrier of large rate charging at low temperature,which reduced the risk of lithium evolution from artificial graphite.