A tough, elastic ion gel with adaptive interface for high performance and safe lithium metal anodes

Lithium metal batteries (LMBs) with high energy densities are highly desirable for energy storage. However, they suffer from the low Columbic efficiency (CE) because of the continuous breaking of solid electrolyte interphase (SEI) and formation of dead lithium generated from the infinite volumetric changes of lithium metal anodes. Herein, a tough and elastic gel electrolyte is designed to create a dynamic interface between lithium metal and gels to tackle this grand challenge. A stable cycling of lithium metal anodes is achieved with a high CE of 99.3% for 1000 cycles and ultralong cycle life of 2,000 h, with traditional ether electrolytes. In-situ optical microscopy insights into the interfacial evolution of the lithium electrode employing gel as electrolyte reveals the uniform Li plating/stripping behavior and the eliminated bubble phenomenon observed in Celgard system, yielding in-depth comprehensions of the precipitation mechanism and interfacial establishment in gel-based LMBs.