Interfacial system optimization and dynamic self-healing for solid-state lithium metal batteries with high critical current density and long-term cycling stability

Solid polymer electrolytes (SPEs) in lithium metal batteries (LMBs) face critical challenges stemming from poor solid–solid interfacial contact, unstable solid electrolyte interphase (SEI) and uneven lithium deposition. These issues are further exacerbated during the battery dynamic cycling, leading to a severe interfacial degradation. To address these challenges, we propose a system optimization and dynamic self-healing strategy, in which the in-situ polymerization of vinyl ethylene carbonate (VEC) enhances solid–solid interfacial contact and the functional indium fluoride (InF₃) additives ensure dynamically self-healing of the interfacial defects by forming a lithium fluoride (LiF)-rich SEI and lithium-indium (Li-In) alloys during cycling. Consequently, the assembled Li||Li symmetric cells exhibit a tenfold improvement in critical current density (CCD) and achieve an ultra-long cycle lifespan over 6500 h. Furthermore, Li||LiFePO₄ (LFP) full cells demonstrate high cycle stability, retaining 84.5% of their capacity over 800 cycles. Remarkably, the pouch cells maintain normal operation even after being folded or cut, underscoring the robustness and practicality of this interfacial system-optimization and self-healing strategy. These findings provide a promising pathway for advancing the performance and reliability of solid-state LMBs and other metal-based energy storage systems.