N-Doped Li2ZrCl6-Based Chloride Solid Electrolytes for Enhanced Li Ion Transport

N-doped Li2ZrCl6−3xNx chloride solid electrolytes were synthesized via a mechanochemical method, and the effects of N incorporation on crystal structure, Li local environment, and Li+ transport were systematically investigated. X-ray diffraction suggested that the main Li2ZrCl6-related diffraction features were largely retained, while N introduction induced partial structural evolution toward C2/m-related features. 7Li MAS NMR revealed that N incorporation sharpened Li resonance peaks. Among the series, Li2ZrCl5.7N0.1 exhibited the highest room-temperature ionic conductivity of 1.15 mS cm−1, with the lowest activation energy of 0.237 eV, demonstrating a reduced Li+ migration barrier. All-solid-state batteries incorporating Li2ZrCl5.7N0.1 showed stable rate capability and long-term cycling, retaining 85.9% capacity after 500 cycles at 1C and 77.4% after 3000 cycles at 3C. These results suggest that appropriate N modification can tune the Li2ZrCl6-based structure and Li local environment, thereby improving Li+ transport in all-solid-state lithium batteries. This work provides a feasible strategy for improving chloride-based solid electrolytes for next-generation energy storage.