A rigid-flexible coupling gel polymer electrolyte towards high safety flexible Li-Ion battery

摘要

Presently, the commercial applications of gel polymer electrolytes (GPEs) in Li-ion batteries (LIBs) is still limited. Here, a novel large-scale feasible poly(vinyl acetate) (PVAc) incorporating poly(vinylidene fluoride)-cohexafluoropropylene (PVDF-HFP)/SiO2 membrane is prepared by a simple solution casting method. Then, the dry membrane is directly swollen by LiPF6-carbonate based electrolyte to obtain a rigid-flexible coupling GPE. The solubility of PVAc into electrolyte is greatly alleviated due to the intermolecular complexation between PVAc and PVDF-HFP. This PVAc/PVDF-HFP/SiO2 based GPE enables LiNi0.5Co0.2Mn0.3O2 (NCM523)/mesocarbon microbeads (MCMB) full cell with excellent cycling stability and rate capability. Based on conventional hot calendar `Bellcore" technology, a NCM523/MCMB pouch cell prototype using this GPE is successfully fabricated, demonstrating both excellent flexibility and high tolerance to mechanical abuse. By saving the complicated pore-regulating procedure, the design concept of rigid-flexible coupling GPE will provide new perspective on the promotion of conventional hot calendar `Bellcore" technology.