The plasticizer-free composite block copolymer electrolytes for ultralong lifespan all-solid-state lithium-metal batteries

Abstract

Solid polymer electrolytes (SPEs) are regarded as one of the most promising substitutes for liquid electrolytes to construct highly safe electrochemical energy storage. While liquid plasticizers are frequently employed in SPEs to enhance ionic conductivity, it is inevitably accompanied by a deficiency in safety. Herein, we report plasticizer-free composite block copolymer electrolytes (BCEs) with conductive nanodomains for ultralong lifespan all-solid-state Li-metal batteries (ASSLBs). The composite BCEs with poly(ether-block-amide) (Pebax) block copolymer as a conductive framework and polyethylene glycol dimethyl ether (PEGDE) as a regulator, can connect and manipulate the highly conductive nanodomains. Compared with homopolymer poly(ethylene oxide) (PEO), the conductive nanodomains in composite BCEs with tunable size can manipulate the Li+ transport channel, effectively enhancing the Li+ conductivity and homogenizing the Li+ deposition. In addition, the thin and dense hybrid solid electrolyte interface (SEI) layer, as well as the potent mechanical strength of composite BCEs, can synergistically suppress the dendrite growth. Therefore, the all-solid-state LiFePO4/Li cells achieve impressive electrochemical performance with a tiny capacity reduction of 0.0127% per cycle for more than 1350 cycles at 0.5 C. This work aims to give impetus to the development of practical ASSLBs which meet the demands for high safety, long lifespan, and mass production.