Tailoring Ionic Conductivity of Block Copolymer Electrolytes with End-functionalized Homopolymers

Block copolymer electrolytes based on poly(ethylene oxide) (PEO) have been regarded as promising candidates of solid electrolyte materials for lithium ion batteries. This is attributed to their ability to dissolve lithium salts and high ionic conductivity of the resultant polymer/salts complexes. However, PEO crystallization below its melting temperature has been tied to a radical reduction in ionic conductivity, especially at room temperature, various attempts have been made to reduce the PEO crystallinity. Herein, we propose a new method to modulate crystallization behavior of PEO-based block copolymers with embedded end-group-functionalized PEO homopolymers. Intriguing, the morphology and ionic conductivity of the resultant block copolymer/homopolymer blends were sensitive function of the type of end group in PEO homopolymers at the same blend ratio. Our approach offers a platform for the development of efficient solid-state polymer electrolytes by controlling intermolecular interactions in PEO phases via a simple end-group chemistry.