水分对LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2/Li_4Ti_5O_(12)电池高温性能的影响

采用LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2三元正极材料匹配钛酸锂(Li_4Ti_5O_(12))负极材料,制备8 Ah软包装锂离子电池,注液前分别烘烤24 h和36 h,电芯水分约为0.030%和0.015%,研究水分对电池高温性能的影响。与水分0.015%的电池相比,水分0.030%的电池首次库仑效率较低,极化明显。在55℃下高温搁置7 d后,电池容量保持率和恢复率结果显示:水分0.030%的电池为98.5%和99.4%,而水分0.015%的电池为99.5%和100.1%,均高于0.030%水分的电池;55℃下3 C循环(1.5~2.7 V)第2 000次时,0.030%和0.015%水分的电池容量保持率分别为87.8%和89.4%。较低的水分可提高电池在高温下的搁置和循环性能。

Effect of moisture on high temperature performance of LiNi0.5Co0.2Mn0.3O2/Li4Ti5O12 battery

A 8 Ah soft pack Li-ion battery was prepared,using LiNi0.5Co0.2Mn0.3O2 as ternary cathode material and lithium titanium oxide(Li4Ti5O12) as anode material.The influence of moisture (0.030％ and 0.015％) on the high temperature performance of the battery was investigated,when the battery was backed 24 h and 36 h respectively before injection.When the moisture was 0.030％,the initial Coulombic efficiency of the battery was lower and the polarization was larger than the one with the moisture of 0.015％.After keeping at 55 ℃ for 7 d,the capacity retention and recovery ratios of the battery with the moisture of 0.030％ were 98.5％ and 99.4％,respectively,while the one with the moisture of 0.015％ were 99.5％ and 100.1％.The capacity retention ratios of the batteries with the moistures of 0.030％ and 0.015％ after 2 000 cycles at 3 C were 87.8％ and 89.4％,respectively.The lower moisture could enhance the storage and cycling performance of the battery at high temperature.