LiFePO_(4)锂离子电池的低温性能改进  

The improving of low temperature performance of LiFePO_(4) Li-ion battery

作　　者：苏林华 高春辉 陈明国 张炜鑫 SU Lin-hua;GAO Chun-hui;CHEN Ming-guo;ZHANG Wei-xin(State Grid Inner Mongolia Eastern Power Co.,Ltd.,Hohhot,Nei Mongol 010000,China;State Grid Power Research Institute Wuhan Nanrui Co.,Ltd.,Wuhan,Hubei 430074,China)

机构地区：[1]国网内蒙古东部电力有限公司,内蒙古呼和浩特010000 [2]国网电力科学研究院武汉南瑞有限责任公司,湖北武汉430074

出　　处：《电池》2022年第1期63-66,共4页Battery Bimonthly

基　　金：国网内蒙古东部电力有限公司科技项目(SGTYHT/19-JS-215)。

摘　　要：利用多巴胺自聚合原理,通过包覆一层氮掺杂的碳质材料(无定型碳)来降低磷酸铁锂(LiFePO_(4))材料的表面电阻,提高低温下Li+迁移速率。采用含氟有机溶剂氟代碳酸乙烯酯,以物质的量比为1∶1的双三氟甲磺酰亚胺锂(LiTFSI)和双(五氟乙基磺酰基)亚胺锂(LiBETI)为混合锂盐,制备1 mol/L混合锂盐电解液(MLiE),以解决电池在低温环境下性能下降的问题。与目前的商业LiFePO_(4)/石墨电池相比,组装使用MLiE的LiFePO_(4)锂离子电池在-20℃于3.65~2.50 V充放电,0.1 C、0.2 C、0.5 C和1.0 C放电容量分别增加了37.4%、44.6%、51.1%和65.3%。A layer of nitrogen doped carbonaceous material(amorphous carbon)was coated to reduce the surface resistance of lithium iron phosphate(LiFePO_(4)) materials and improve the migration rate of Li^(+) at low temperature based on the principle of dopamine self-polymerization.A fluorine-containing organic solvent(fluorovinyl carbonate)was used to prepare mixed 1 mol/L lithium salt electrolyte(MLiE)by adding mixed lithium salt lithium trifluoromethylsulfonimide(LiTFSI)and lithium bis(pentafluoroethyl sulfonate)imine(LiBETI)with a molar ratio of 1∶1,so as to solve the problem of battery performance degradation in low temperature environment.Compared with the current commercial LiFePO_(4)/graphite battery,the discharge capacity of the assembled LiFePO_(4) Li-ion battery with MLiE at 0.1 C,0.2 C,0.5 C and 1.0 C(3.65-2.50 V)under-20℃increased by 37.4%,44.6%,51.1%and 65.3%,respectively.

关 键 词：正极改性 混合锂盐电解液 低温 性能优化 多巴胺 

分 类 号：TM912.9[电气工程—电力电子与电力传动]