二氟磷酸锂对MCMB负极性能的影响

采用恒流充放电、电化学阻抗谱(EIS)、SEM及X射线光电子能谱(XPS)等方法,研究无机锂盐二氟磷酸锂(LiPO2F2)对锂离子电池负极材料中间相碳微球(MCMB)性能的影响。当电解液中LiPO2F2的含量为1.0%时,MCMB/Li电池在1.50~0.01 V以0.2 C放电、1.0 C充电循环100次,容量保持率为96.9%,比未添加LiPO2F2电解液的电池提高了22.0%。主要原因是LiPO2F2的加入有利于电极表面形成更稳定、致密的固体电解质相界面(SEI)膜,降低电极界面阻抗。

Effects of lithium difluorophosphate on performance of MCMB anode

The effects of inorganic lithium salt lithium difluorophosphate(LiPO2F2) on the performance of mesocarbon microbeads(MCMB) anode material in the Li-ion battery were studied by methods of galvanostatic charge-discharge,electrochemical impedance spectroscopy(EIS),SEM and X-ray photoelectron spectroscopy(XPS).When cycled in 1.50-0.01 V with a discharge current of 0.2 C and a charge current of 1.0 C,the capacity retention of the MCMB/Li cell with 1.0% LiPO2F2-containing electrolyte after 100 cycles reached 96.9%,which was 22.0% higher than that without LiPO2F2 addition.The addition of LiPO2F2 facilitated the formation of a stable and dense solid electrolyte interface(SEI) film,thereby reduced the interfacial impedance.