In-Situ Functional Crosslinking Enables Facile Construction of Rigid Poly(Ethylene Oxide) Network for High Performance All-Solid-State Batteries

Abstract

Poly(ethylene oxide) (PEO) based electrolytes have garnered considerable attention in all-solid-state lithium metal batteries with superior safety and energy density, but suffer from low-ion conductivity and poor cycling stability. Herein, a novel in-situ functional crosslinking strategy is proposed to overcome these limitations simultaneously, where a two-in-one bis-diazirine molecule (C1) is not only used as a rigid cross-linker, but also functions as an electron-withdrawing inducer. Benefitting from such an integration of two functionalities into one cross-linker, a rigid PEO electrolyte network can be facilely constructed, while exhibiting disrupted crystallization, robust mechanical strength, loosened Li─O binding to boost the Li⁺ transport, and anion-rich Li⁺ coordinated structure to favor the generation of a stable LiF-rich solid electrolyte interface. As a result, a remarkable ion conductivity of 1.4 × 10⁻³ S cm⁻¹ is achieved at 60°C together with a Li⁺ transference number of 0.63. And the corresponding LiFePO₄||Li and NCM811||Li filled batteries present significantly improved rate performance and capacity retention cycling life compared with the pristine PEO electrolyte, highlighting the great potential of in-situ functional crosslinking for high performance all-solid-state batteries.