LiPF_6/LiBOB混合锂盐改善LiFePO_4/石墨动力电池高温循环性能研究  

Use of LiPF_6/LiBOB blend salt for improving cycling performances of LiFePO_4/graphite battery at elevated temperature

作　　者：宋海申[1,2] 赖延清[1,2] 李劼[1,2] 刘业翔[1] 张治安[1,2] 

机构地区：[1]中南大学冶金科学与工程学院,湖南长沙410083 [2]中南大学深圳研究院深圳高性能电池材料与器件工程研究中心,广东深圳518057

出　　处：《功能材料》2013年第19期2849-2853,共5页Journal of Functional Materials

基　　金：国家科技支撑计划资助项目(2007BAE12B01);国家自然科学基金资助项目(20803095)

摘　　要：分别以LiPF6、LiBOB和LiPF6/LiBOB混合盐为电解质,研究了不同电解液对LiFePO4/石墨动力电池高温循环性能的影响。结果表明,LiBOB盐抑制了正极溶铁行为,并提高了正极高温循环充放电效率;由于LiBOB基电解液对正极的保护及在负极表面良好的成膜作用,使得LiFePO4/石墨电池高温循环性能得到明显改善,但是增大了电池阻抗。LiPF6/LiBOB混合盐可以发挥LiBOB盐的优点增加正极稳定性,在石墨表面形成致密的SEI膜并能够有效改善电池高温循环性能,同时避免了单纯使用LiBOB盐时阻抗较高的缺点。使用LiPF6/LiBOB混合盐,利用LiPF6盐低阻抗特性及LiBOB盐对正、负电极的保护作用,可以有效提高电池电化学性能。LiPF6, LiBOB and LiPF6/LiBOB blend salt-based electrolytes were investigated for improving cycling performances of LiFePO4/graphite lithium-ion batteries at elevated temperature. It was demonstrated that dis- solution of Fe from LiFePO4 was depressed in LiBOB based electrolyte, and columbic efficiency of LiFePO4/Li cell at elevated temperature was increased; LiBOB was reduced earlier on anode surface, forming compact SEI layer; and the capacity retention of LiFePO4/graphite cells at 55℃ increases with LiBOB concentration due to protective depositions of LiBOB on cathode surface and the SEI layer on anode surface, while the impedance of the cell is increased. LiPF6/LiBOB blend salt-based electrolyte combines the advantages of the different salts and maximizes the performance of cells. When electrolytes with LiPF6/LiBOB blend salt was used, the LiFe- PO4/graphite cells have excellent capacity retention at 55℃, while the impedance was dramatically decreased.

关 键 词：动力电池 LIBOB 混合盐 LIFEPO4 循环 高温 

分 类 号：TM912[电气工程—电力电子与电力传动]