摘要
本论文合成了阻燃添加剂三(2,2,2-三氟乙基)磷酸酯(TFP),并将其与负极成膜添加剂复配组成高安全性电解液,以提高锂离子电池的安全性和电化学性能。在基准电解液(1.0 mol/L LiPF_6/EC+DEC(1∶1,v/v))中引入5%~20%TFP,电解液的阻燃性能显著提高;当TFP含量增加到20%时,电解液几乎不燃。但含20%TFP的高安全性电解液在石墨/LiCoO_2电池体系中的循环性能较差,半电池的测试结果表明:TFP与石墨负极兼容性较差。通过添加质量分数为1%的成膜添加剂(碳酸亚乙烯酯(VC)、1,3-丙烷磺酸内酯(PS)、氟代碳酸乙烯酯(FEC)),组成阻燃-成膜添加剂复配电解液体系,来改善20%TFP电解液的电化学性能,其中1%FEC的改善效果最显著:在石墨/LiCoO_2全电池体系和石墨/LiFePO_4全电池中都表现出优异的电化学性能,表明该阻燃-成膜添加剂复配的高安全性电解液具有重要的研究价值和广阔的应用前景。
In order to improve the safety and the electrochemical performance of the lithium ion batteries,tris(2,2,2-trifluoroethoxyl)phosphate(TFP)is synthesized and applied as a flame retardant to form complex electrolyte systems combining with film-forming additives in this work.When 5%~20% TFP is introduced into the base electrolyte of 1.0 mol/L LiPF_6/ethylene carbonate(EC)+diethyl carbonate(DEC)(v∶v/1∶1),the flammability of electrolytes decreases significantly.The electrolyte containing 20% TFP is almost nonflammable,but it exhibits poor electrochemical stability in Graphite/LiCoO_2 because of its bad compatibility with the graphite anode.Introduction of 1% film-forming additives including vinylene carbonate(VC),1,3-propylene sulfate(PS),or fluoroethylene carbonate(FEC),can improve the electrochemical performances of the lithium ion batteries with the 20% TFP electrolyte,and especially 1% FEC has shown the best performance in the full cells of Graphite/LiCoO_2 as well as Graphite/LiFePO_4.The complex electrolyte system with 20% TFP and 1% FEC has shown great research significance and a wide application prospect.
出处
《电池工业》
CAS
2017年第4期1-6,13,共7页
Chinese Battery Industry
基金
国家自然科学基金(Nos.51372060
and 21676067)
中央高校基本业务费
关键词
锂离子电池
复配体系
阻燃添加剂
负极成膜添加剂
Li-ion batteries
Complex electrolyte system
Flame retardant
Anode film-forming additives
