A review of progress in proton ceramic electrochemical cells: material and structural design, coupled with value-added chemical production

Proton ceramic electrochemical cells (PCECs) have attracted significant attention from governmental institutions and research societies as an emerging technology for energy conversion and storage. As some of the representative high-temperature electrochemical devices, PCECs have achieved impressive progress and become an influential research direction in the energy field. They exhibit wide-ranging application prospects and offer numerous possibilities for the subsequent production of valuable chemical products at intermediate temperatures, due to their remarkable flexibility and reliability. The development of efficient, stable, and long-life elementary PCEC devices relies heavily on the exploitation of new materials and structural designs. In this paper, we provide a general review of the mechanisms of proton transport and the fundamental operating principles of PCECs. We comprehensively summarize strategies used to improve electrochemical performance in the past few years, encompassing the state-of-the-art electrode and electrolyte materials, novel approaches for structural optimization, and innovative developments in electrochemical cell devices. Importance is given to the presentation of various applications of PCECs, including H 2 O electrolysis, CO 2 /H 2 O co-conversion in the electrolysis mode, and the synthesis of high-value chemicals such as CH 4 and CO through CO 2 electrochemical conversion with proton donors like H 2 , C 2 H 6 , or NH 3 (conceptualized). Consequently, we provide a future perspective on PCEC commercialization and highlight the existing challenges that need to be addressed. Improved performance of proton ceramic electrochemical cells (PCECs) through material development and structural design, and application of PCECs for efficient energy conversion render them promising for clean energy and sustainable development.