Dynamic Anion Space Gradient Distribution Drives Wide-Temperature-Range All-Solid-State Lithium-Ion Batteries

To address the critical challenges of poor ionic conductivity, insufficient interfacial stability, and narrow operating temperature range in all-solid-state lithium batteries (ASSLBs), this work develops a dynamic anion functionalization strategy to design and synthesize a new class of yttrium-based rare-earth halide solid-state electrolytes (SSEs). It is found that the dynamic anions can not only statically modify the lattice but also undergo reversible dynamic migration during cycling, thereby transforming the traditional single-cation conductor into a cation-anion synergistic conductor, which significantly enhances the overall ionic conductivity. Furthermore, the dynamic anions facilitate a gradient LiF protection layer on the cathode side to improve high-voltage compatibility and form a dense Li₃N-LiF-LiI composite adaptive interphase on the anode side, effectively suppressing dendrites and stabilizing the interface. The assembled ASSLBs based on the dynamic anion strategy demonstrate stable operation across a wide temperature range from extreme cold (-30°C) to high temperatures (140°C), while delivering high specific capacity, long cycle life, and outstanding safety characteristics. Our findings establish a new paradigm for developing next-generation ASSLBs capable of reliable operation under extreme conditions.