Renewable hydrogen is crucial for decarbonization but is currently not cost-competitive with fossil fuels due to low energy efficiency and high costs of traditional water electrolyzers. This paper introduces a capillary-fed electrolysis (CFE) cell, where water is supplied to electrodes via capillary action through a porous separator, enabling bubble-free operation. An alkaline CFE cell achieves superior performance to commercial cells, with a cell voltage of 1.51 V at 0.5 A cm⁻² and 85 °C, equating to 98% energy efficiency (40.4 kWh/kg hydrogen). Simplified balance-of-plant further enhances cost-competitiveness, bringing cost-competitive renewable hydrogen closer to reality.

Aaron Hodges, Anh Linh Hoang, George Tsekouras, Klaudia Wagner, Chong-Yong Lee, Gerhard F. Swiegers, Gordon G. Wallace