Electrochemical hydrogen compressor: Recent progress and challenges

Hydrogen has higher specific energy than conventional fuels but compared per unit volume under normal conditions, its energy density is lower. This difference is compensated with compression. Theoretically, compression is possible with a proton exchange membrane electrolyzer (PEME), in the process of hydrogen production, but the hydrogen permeation to the oxygen side forms a potentially explosive mixture. An electrochemical hydrogen compressor (EHC) with an analogous working principle presents the most promising solution due to its noiseless and vibration-free operation, modularity, absence of moving parts, and higher efficiency compared to mechanical compressors. Hydrogen purification and its extraction from gaseous mixtures are additional benefits that give electrochemical compression further advantage. This paper discusses the working principle of electrochemical hydrogen compression technology and its design development. The focus is on research trends, recent advances, and transpired challenges. In addition, reviewed literature aspects not studied sufficiently are highlighted, and future research directions are proposed.