High Centrifugal Field Coupling with Electrolyte Circulation Internals: Process Intensification toward Efficient Water Electrolysis for Hydrogen Storage via Power-to-Gas

Water electrolysis has the potential to become a key element for the conversion of surplus wind/solar electricity into H-2 via power-to-gas (P2G) in a future sustainable energy system. However, water electrolysis suffers from low energy efficiency owing to the high overpotential and large ohmic voltage drop. In this study, the effect of the centrifugal field on the hydrogen evolution reaction (HER) was studied, and the overpotential of the HER was measured by Tafel polarization. The results showed that the HER overpotential was reduced significantly as the centrifugal coefficient increased because the bubble separation from the electrode surface was improved. To reduce the ohmic voltage drop, a novel water electrolysis system with electrolyte circulation internals was designed. The cell voltage in water electrolysis was reduced, and thus, the electrolytic efficiency increased. This was attributed to the reduction of the solution resistance by the discharge of bubbles in the electrolyte. Therefore, high centrifugal field coupling with electrolyte circulation internals is an effective way to enhance the efficiency of water electrolysis. This study provides a theoretical basis for the development of new industrial water electrolysis devices for hydrogen production.