Ethylene oxide based polymer electrolytes with fluoro-alkyl moiety for stable lithium metal batteries
Journal
Ionics
Date
2020.07.01
Abstract
In this work, we have developed a new ethylene oxide (EO)-based polymer electrolyte (PE) containing a fluoro-alkyl moiety, which possesses high oxidative decomposition potential as well as sufficient ionic conductivity and mechanical property for the application to Li metal batteries. Especially, we designed the partially fluorinated copolymer, which is improved in conventional polyethylene oxide systems to use it as both stable electrolyte matrix and electrode binder for high voltage applications. The results show that the stabilization of the EO-based PE against a high voltage operation of Li metal battery is significantly improved by the introduction of a fluoro-alkyl moiety, which is performed via simple radical copolymerization. The synthesized copolymer exhibits satisfactory physical stability and unprecedented high oxidation decomposition voltage threshold over 4.5 V. The PEs also reveal moderate ionic conductivity (> 0.3 mS cm-1 @ 60 °C), preserving the intrinsic property of EO-based polymer.