Air Stability of Inorganic Electrolyte for All-Solid-State Lithium Batteries: Advances, Challenges, and Perspectives

The development of all-solid-state lithium batteries (ASSLBs) has emerged as a pivotal trajectory in the ongoing evolution of next-generation battery technology, owing to their substantial energy density and inherent safety benefits. However, existing solid-state electrolytes (SSEs) still face challenges in meeting the operational requirements of ASSLBs, primarily due to their intrinsic chemical instability under ambient atmospheric conditions. This review systematically analyzes the air instability mechanisms of three major inorganic solid-state electrolytes (ISEs) categories: sulfide-, oxide-, and halide-based ISEs. Building on this foundation, the work comprehensively discusses three strategic approaches to enhance ISE air stability: doping modification, protective layer engineering, synthesis process optimization. Notably, this review reveals cross-system applicability of modification strategies among different ISE categories. These insights provide critical guidance for designing air-stable ISEs. Finally, based on cutting-edge research advancements, the review outlines future directions for holistic performance optimization of ISEs, highlighting the transformative role of AI-driven approaches.