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.
Keywords: cross-linking; lithium ion battery; solid-state electrolyte; succinonitrile; ultraviolet irradiation.