The Detail Matters: Unveiling Critical Parameters in the Scalable Synthesis of Halide Solid State Electrolytes

Halide solid-state electrolytes (SSEs) have emerged as a promising candidate for all solid-state batteries owing to the high ionic conductivity, compatibility with high-voltage cathodes, and favorable deformability. As research on halide SSEs continues to advance, their performance has been substantially enhanced, bringing these materials to the threshold of commercialization. The large-scale synthesis of electrolytes constitutes a crucial initial step for their commercialization. However, current research has mainly focused on performance optimization, with limited attention given to scalable synthesis processes. Herein, from an engineering perspective, we systematically investigate the key parameters that require attention during the large-scale preparation of halide SSEs. Experimental results show that, compared with the solid-phase ball-milling method, the solution method produces electrolytes with smaller particle sizes, lower cost, better batch-to-batch consistency, and higher yield, demonstrating advantages for large-scale synthesis. Furthermore, we investigate how precursor addition sequence, solution concentration, and annealing atmosphere affect the performance of halide SSEs synthesized via the solution route. Besides, challenges such as hydrolysis, corrosion, and temperature rise effects are encountered during solution-based synthesis. Among these, hydrolysis directly affects product purity, while corrosion and temperature rise effects impose high demands on the acid resistance and heat dissipation capacity of reaction vessels. Consequently, the corrosion resistance of the reaction vessel and heat dissipation are among the factors that require consideration during large-scale synthesis. This study provides the systematic analysis of synthesis process from an engineering perspective and proposes design criteria for reaction vessels tailored to large-scale preparation, aiming to offer new insights for the industry.