Preparation and performance of poly(ethylene oxide)‐based composite solid electrolyte for all solid‐state lithium batteries

ABSTRACT Poly(ethylene oxide)‐based solid electrolyte is attractive for using in all solid‐state lithium batteries. However, the polymer has a certain degree of crystallization, which is adverse to the conduction of lithium ions. In order to overcome this drawback, a flexible composite polymer electrolyte (CPE) containing TiO 2 nanoparticles is elaborately designed and synthesized by tape casting method. The effects of different molar ratios of EO: Li and mass fraction of TiO 2 on the physical and electrochemical performances are carefully studied. The results show the CPE10 having 10 wt % TiO 2 has the lowest degree of crystallinity of 9.04%, the lowest activation energy of 8.63 × 10 −5 eV mol −1 . Besides, the CPE10 shows a lower polarization and higher decomposition voltage. Thus, prepared all solid‐state battery LiFePO 4 /CPE10/Li shows a high initial capacity of 160 mAh g −1 at 0.1 C, 134 mAh g −1 at 0.5 C and higher capacity retention of 93.2% after 50 cycles at 0.5 C (1 C = 170 mAh g −1 ). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47498.