Solid‐State Electrolyte‐Based Electrochemical Conversion of Carbon Dioxide: Progress and Opportunities

Abstract Research on electrocatalytic CO 2 reduction reaction (CO 2 RR) has been growing rapidly owing to the urgent requirement of sustainable renewable energy. However, several obstacles hinder the application of liquid salt electrolytes in CO 2 RR, such as high costs, low concentrations of the product, and low purity due to the separation process of the product. Solid‐state electrolytes (SSEs) have been introduced as viable alternatives to liquid electrolytes and their salts to address this challenge. Here, we summarize the recently demonstrated studies and opportunities related to catholyte‐free CO 2 RR using SSEs. The recent studies are classified based on the product, including the CO 2 RR electrolyzer performance. Different SSEs are briefly discussed to highlight the new opportunities in CO 2 RR application. We also describe the basic operation parameter of the catholyte‐free CO 2 RR using SSE, which has been studied before as the key variable of the reactor. This review provides insights on minimizing the use of salt electrolytes for CO 2 RR and reveal opportunities for using this technique to improve the efficiency of CO 2 RR on a large scale. The exploration of utilizing solid‐state electrolytes (SSE) on a scale‐up production has been pursued to showcase their viability in integrating them into commercial CO 2 RR technology.