Constructing zero-external-pressure high-performance sulfide all-solid-state pouch cells via asymmetric interfacial electrophilicity.

Abstract

Sulfide solid electrolyte (SSE)-based all-solid-state lithium metal batteries (ASSLBs) attract great attention owing to high ion conductivity and mechanical deformability. However, the practical application of pouch cells is hindered by their heavy reliance on high-external-pressure to maintain the interfacial contact. Here, we design an asymmetric interfacial electrophilic composed of electron buffer layers and ion conductor layers and realize the room-temperature stable cycling of sulfide-based ASSLB pouch cells under a complete zero external pressure. The lithium-tin alloy side undergoes fast electrophile-induced reconstruction while lithium iodide stays inert, forming an asymmetric interfacial electrophilic response, which enables the stable and reversible lithium deposition/stripping under a zero external pressure. The coin cell retains 81.1% of its initial discharge capacity after 5000 cycles at 2 C. The assembled pouch cell (∼376 watt-hours per kilogram) demonstrates a record zero-external-pressure cycling stability with a capacity retention of 85.7% over 300 cycles and exhibits a stable cyclability even at 0°C. This study offers an effective strategy to accelerate the practical realization of sulfide-based ASSLBs.