Recent Progress in Solid‐State Electrolyte for Electrocatalytic CO ₂ Reduction

Abstract The electrocatalytic CO 2 reduction reaction (CO 2 RR) has garnered significant attention in recent years as a promising method for mitigating CO 2 emissions and generating value‐added carbon‐neutral fuels. Electrolyte, a crucial component of the CO 2 RR device, exerts a profound influence on the electrocatalytic efficiency and product distribution of CO 2 RR. The utilization of solid‐state electrolytes is considered an innovative and effective strategy to address the shortcomings of liquid electrolytes, such as low solubility of CO 2 in aqueous electrolytes, mixing of liquid products with electrolytes, and carbon loss due to carbonate crossover. This review first summarizes the development of electrolyzers and discusses the limitations of liquid electrolyte existing in electrocatalytic CO 2 RR systems. Then, the primary types and key performance indexes of solid‐state electrolytes are reviewed, highlighting their notable advantages for electrocatalytic CO 2 RR. Importantly, major applications of solid‐state electrolyte in electrocatalytic CO 2 RR research are enumerated. Finally, challenges and opportunities are proposed for future development of solid‐state electrolyte in electrocatalytic CO 2 RR technology.