High‐Temperature Long‐Term Cycling Capability of Lithium Batteries Enabled by Releasing Local Constriction

Reusable interstellar exploration and commercial spaceflight urgently require the development of high‐temperature secondary battery technology. However, metal/semimetal anodes contributing to high theoretical capacity are prone to creep at high temperatures, which raises significant concerns about battery safety and cycling performance. Here, we identify the generation of Li‐rich phases at anodes that leads to the sustained degradation of high‐temperature batteries. The non‐conformal interface between anode and electrolyte constricts lithiation in local contact areas, resulting in extremely low chemical potential and subsequent evolution of high temperature unstable Li‐rich phases. We therefore designed a heat‐resistant anode featuring a Zintl‐like phase core and an ion‐electron co‐conducting conformal coating, which releases local constriction while inhibiting high‐temperature interfacial deactivation. Consequently, solid‐state battery (SSB) assembled with this designed anode can stably cycle over 1,000 cycles at 120 °C (2C, pouch cell‐340 Wh kg −1 ). Particularly distinguishing itself from molten salt high‐temperature batteries, the SSB exhibits outstanding temperature adaptability in full‐temperature dynamic tests (−40–150 °C).