Cesium Phosphates as Electrolytes for Electrochemical Cells in Intermediate‐Temperature Fuel Cells and Electrolysis: A Review

Cesium phosphates constitute a unique class of intermediate-temperature proton conductors distinguished by their characteristic proton transport mechanisms and adequate thermal stability within the intermediate-temperature regime. These properties have enabled their development as practical electrolytes for electrochemical cells used in fuel cells and an expanding range of electrolysis reactions. This review outlines recent advances in cesium-phosphate-based electrochemical systems, tracing the progression from fundamental proton conduction mechanisms to device-level implementation. Particular emphasis is placed on electrolysis applications, an emerging and largely unexplored research area. Operating in the intermediate-temperature regime establishes a distinctive platform that integrates advantages typically associated with low-temperature systems-such as tunable product selectivity-with the accelerated reaction kinetics characteristic of high-temperature operation. These attributes position cesium phosphates as promising electrolytes for next-generation electrochemical technologies and highlight the need for continued advances in electrode design, interfacial engineering, and system integration.