Insight into the Role of Fluoroethylene Carbonate in Solid Electrolyte Interphase Construction for Graphite Anodes of Lithium-Ion Batteries
Lingling Huang, Shuai Chen, Jiaqi Zhan, Jiajiong Liang, Suli Li, Hai Wang, Mengqing Xu, Weishan Li
Abstract
The role that fluoroethylene carbonate (FEC) plays in the construction of the solid electrolyte interphase (SEI) on graphite anodes of lithium-ion batteries is understood by theoretical calculations combined with electrochemical measurements and spectral characterizations. It is found that FEC is different from ethylene carbonate (EC), although they have a similar structure. FEC presents a stronger ability than EC to combine with PF 6 –, which is helpful for the reduction of LiPF 6 to construct a LiF-rich inner layer of SEI. Additionally, FEC has a more negative electron affinity than EC, which makes it much easier to reduce, resulting in F-containing polymers that contribute to the outer layer of SEI. Consequently, the FEC-constructed SEI endows the graphite anode with excellent cycling stability.