Design and synthesis of a single ion conducting block copolymer electrolyte with multifunctionality for lithium ion batteries

Abstract

A novel single ion conducting block copolymer electrolyte (SI-co-PE) for applications in lithium-ion batteries is presented. The block copolymer is made of alternative ethylene oxide (EO) and aromatic segments to tune the glass transition temperature (T_g), the mechanical strength and the porosity of the material for achieving high electrochemical performance of lithium-ion batteries. Upon blending with a PVDF-HFP binder via a solution cast method, a gel SI-co-PE membrane with high ionic conductivity, a wide electrochemical window and a high lithium transference number was obtained. Excellent electrochemical stability and battery performance at both room temperature and 80 °C with various charge–discharge rates were demonstrated. The study underscores the fundamental importance of polymer electrolyte microstructures in battery performance enhancement and suggests ways to improve the design of new electrolyte materials for development of better battery devices with a long cycle life.