A Cross-Linking Succinonitrile-Based Composite Polymer Electrolyte with Uniformly Dispersed Vinyl-Functionalized SiO2 Particles for Li-Ion Batteries

A cross-linking succinonitrile (SN)-based composite polymer electrolyte (referred to as “CLPC–CPE”), in which vinyl-functionalized SiO2 particles connect with trimethylolpropane propoxylate triacrylate (TPPTA) monomers by covalent bonds, was prepared by an ultraviolet irradiation (UV-curing) process successfully. Vinyl-functionalized SiO2 particles may react with TPPTA monomers to form a cross-linking network within the SN-based composite polymer electrolyte under ultraviolet irradiation. Vinyl-functionalized SiO2 particles as the fillers of polymer electrolyte may improve both the thermal stability of CLPC–CPE and interfacial compatibility between CLPC–CPE and electrodes effectively. There is no weight loss for CLPC–CPE until above 230 °C. The ionic conductivity of CLPC–CPE may reach 7.02 × 10–4 S cm–1 at 25 °C. CLPC–CPE has no significant oxidation current until up to 4.6 V (vs Li/Li+). The cell of LiFePO4/CLPC–CPE/Li has presented superior cycle performance and rate capability. The cell of LiFePO4/CLPC–CPE/Li may deliver a high discharge capacity of 154.4 mAh g–1 at a rate of 0.1 C after 100 charge–discharge cycles, which is similar than that of the control cell of LiFePO4/liquid electrolyte/Li. Furthermore, the cell of LiFePO4/CLPC–CPE/Li can display a high discharge capacity of 112.7 mAh g–1 at a rate of 2 C, which is higher than that of the cells assembled with other plastic crystal polymer electrolyte reported before obviously.