Efficient room-temperature solid-state lithium ion conductors enabled by mixed-graft block copolymer architectures
Xiaoyu Ji, Mengxue Cao, Xiaowei Fu, Ruiqi Liang, An N. Le, Qiuting Zhang, Mingjiang Zhong
Abstract
Fast lithium ion (Li+) transport in solid-state polymer-matrix conductors is in desperate demand in a wide range of room-temperature scenarios but remains a formidable challenge. Herein, we designed a class of solid-state electrolytes based on mixed-graft block copolymers (mGBCPs) containing short poly(ethylene oxide) (PEO) and polydimethylsiloxane (PDMS) side chains. The strong immiscibility of PEO and PDMS resulted in the formation of ordered phase-separated nanostructures. Diverse morphologies, including double gyroids, hexagonally perforated lamellae, hexagonally packed cylinders, and lamellae, were observed at different volume fractions of PEO/PDMS blocks. The impact of chain mobility of PEO on Li+ transport was investigated by varying the length of PEO side chains and blending with free PEO chains. We demonstrated that physically blending mGBCPs with free amorphous PEO chains significantly facilitated the Li+ conduction, and a solid-state electrolyte with room-temperature conductivity up to 2.0 × 10−4 S/cm was prepared.