A room-temperature high performance all-solid-state lithium-sulfur battery enabled by a cross-linked copolymer@ceramic hybrid solid electrolyte

Abstract

The use of solid electrolytes (SEs) is a key strategy for enabling the intrinsically safe operation of batteries comprising lithium metal anodes as they suppress the growth of lithium dendrites. Among the different types of SEs, polymer-based hybrid electrolytes (HEs) are highly promising due to their synergetic properties from the constituent polymer matrix and inorganic filler particles. However, the lithium-ion diffusion pathway in HEs is still dominated by the polymer, especially for polyethylene oxide (PEO)-based HEs. The main limitation of PEO is the strong temperature dependence of its ionic conductivity, preventing its use at room temperature (RT). Herein, a cross-linked polymer-based HE with a high ionic conductivity of 1.1 × 10-3 S cm-1 at RT is presented. The novel cross-linked copolymer, composed of pentaerythritol tetraacrylate (PETEA), tri(ethylene glycol) divinyl ether (TEG), and lithium bis(trifluoromethanesulfonyl)-imide (LiTFSI), serves as a matrix to achieve satisfactory mechanical strength. Integrated Li7La3Zr2O12 (LLZO) particles are covalently bound to the copolymer by a prior surface modification step. To demonstrate the suitability of the developed HE for RT application in advanced battery systems, a solid-state lithium-sulfur cell is built which exhibits an initial specific capacity of 688 mA h g-1. The ability of this HE to operate at RT can be expected to boost the development of safe all-solid-state batteries for many applications.