Low-Voltage Hydrogen Peroxide Electrolyzer for Highly Efficient Power-to-Hydrogen Conversion

Power-to-hydrogen conversion via water electrolysis using renewable energy-sourced electricity has been considered for large-scale energy storage and grid balancing. Unfortunately, the state-of-the-art proton exchange membrane (PEM) water electrolyzers are costly and low in energy efficiency because of their use of expensive iridium catalysts and high overpotential to overcome the energy barrier of the oxygen evolution reaction. Here, we demonstrate a low-cost and highly efficient PEM hydrogen peroxide electrolyzer toward power-to-hydrogen conversion, which can be employed in distributed energy storage systems based on the sustainable electrochemical cycle of hydrogen peroxide. This PEM H2O2 electrolyzer utilizes the facile hydrogen peroxide oxidation reaction (HPOR), significantly reducing the anode potential and cell voltage. Using iridium-free HPOR catalysts, the hydrogen peroxide electrolyzers work in a remarkably low-voltage range (0.81–1.12 V) with extremely high voltage efficiency up to 87% and low electric power consumption (ca. 24.8–32.3 kWh/kgH2), paving the way for the future development of economic and environmentally friendly distributed energy storage systems.