LiDFOB对LiCoO_2锂离子电池循环稳定性的影响  

Effect of LiDFOB on cycle stability of LiCoO_2 Li-ion battery

作　　者：廖红英[1] 杨光[1] 王磊[1] 孟蓉[1] 

机构地区：[1]北京化学试剂研究所,北京102607

出　　处：《电池》2017年第2期80-83,共4页Battery Bimonthly

摘　　要：采用线性伏安扫描(LSV)、SEM、X射线光电子能谱(XPS)、恒流充放电等方法,研究二氟草酸硼酸锂(LiDFOB)作为电解液添加剂对钴酸锂(LiCoO_2)正极锂离子电池循环稳定性的影响。在3.0~7.0 V,首次到第4次扫描时,添加LiDFOB的电解液,氧化电流逐渐减小;LiDFOB可在LiCoO_2电极表面形成含有LiF、O-B化合物的保护膜;含3%LiDFOB的电解液可抑制隔膜在常温及高温循环过程中的氧化;使用含1%、3%LiDFOB电解液的LiCoO_2/石墨全电池,循环500次的容量保持率分别为80.88%、86.62%,高于空白组的74.75%。LiDFOB提高电池循环稳定性的原因是:使铝集流体钝化,降低了电解液的氧化分解电流;在正极表面形成保护膜,抑制电解液/电极界面的副反应;对隔膜具有抗氧化保护作用。The effect of lithium difluoro（oxalato） borate （LiDFOB） as an additive in electrolytes on cycle stability of lithium cobah oxide （LiCoO2 ） cathode Li-ion battery was investigated with the methods of linear sweep voltammetry（ LSV ）, SEM, X-ray photoelectron spectroscopy（XPS） and galvanostatic charge-discharge. The oxidation current in LiDFOB-added electrolytes on aluminum foil was gradually decreased from the initial to the fourth scanning during 3.0 -7.0 V. The protection film containing LiF and O-B compouml was founded on the surface of LiCoO2 electrode. The oxidation of the membrane during cycle process was inhibited by using 3% LiDFOB electrolyte at ambient and high temperature. Higher capacity retention rate was measured after 500 cycles of the LiCoOJ graphite battery with 80. 88% （1% LiDFOB-added）and 86. 62% （3% LiDFOB-added） compared to the baseline electrolyte 74. 75%. The cycle stability of the battery was improved within LiDFOB based on such factors ： the corrosion of the aluminum current collector was reduced, the side reactions of the electrolyte/electrode interface were inhibited and the membrane was protected.

关 键 词：二氟草酸硼酸锂(LiDFOB) 电解液添加剂 循环稳定性 钴酸锂(LiCoO2) 

分 类 号：TM912[电气工程—电力电子与电力传动]