石墨负极在Et4NBF4+LiPF6/EC+PC+DMC电解液中的电化学行为

在PC+EC+DMC复合溶剂体系中, 研究了Et4NBF4(四氟硼酸四乙基铵)与LiPF6组成的复合盐电解质对石墨负极材料界面性质的影响. 用循环伏安和恒电流充放电测试方法研究了电解液与石墨负极的相容性, 通过傅里叶变换红外光谱(FTIR)对固体电解质中间相膜(SEI)的成分变化进行了研究. 结果表明, 电解液中的Et4NBF4参与了SEI膜的形成; 当Et4NBF4浓度为0.2 和0.5 mol·L-1时, 电池首次充放电不可逆容量损失明显减少, 循环效率分别上升到76.0%和81.6%. Et4NBF4/LiPF6复合盐电解质改善了PC基电解质与石墨负极的相容性.

Electrochemical Behaviors of Et4NBF4+LiPF6/EC+PC+DMC Electrolyte on Graphite Electrode

Et4NBF4/LiPF6-based electrolytes were investigated to study the effects of the electrolytes with blend solvent EC+PC+DMC on the interface characteristics of graphite electrode. Cyclic voltammetry (CV) and charge-discharge test were used to examine the compatibility between the electrolytes and graphite anode. FTIR spectroscopy was used to analyze the variational component of the solid electrolyte interface (SEI) film. The results showed that Et4NBF4 was concerned with the formation of SEI film. Irreversible capacity in the first circle remarkably reduced when the concentrations of Et4NBF4 were 0.2 and 0.5 mol·L-1, and the circle efficiencies rose to 76.0% and 81.6%, respectively. LiPF6/Et4NBF4 blend-salt electrolytes system can effectively improve the compatibility between PC-based electrolyte and graphite anode.