A group of academics from Sweden’s Uppsala University and the Swedish technology business Solibro Research AB have created a solar-powered electrolyzer for water splitting that has a high solar-to-hydrogen (STH) efficiency, according to the researchers.
The device is described as an electrolysis device combining copper, indium, gallium, and selenium (CIGS) thin-film solar modules with an alkaline electrolyzer based on a trimetallic cathodic catalyst made of nickel, molybdenum, and vanadium (NiMoV) and an anode made of nickel oxide in the paper NiMoV and NiO-based catalysts for efficient solar-driven water splitting using thermally integrated photovolt (NiO).
The anodic NiO electrocatalyst is employed as a counter-electrode to the NiMoV cathode in the proposed system architecture. The electrolysis cell’s anode and cathode were positioned in close proximity to one another and separated by an anion exchange membrane, with thin glass serving as the cell’s wall to allow thermal coupling and heat exchange.
“The anodic and cathodic catalysts were positioned in close proximity in the design to minimize mass transport limitations in the design,” the scientists explained. “Modules of this size could be assembled into arrays for larger area installations for convenient maintenance and replacement of separate modules.” “The technique enables for heat transfer between the PV and electrolysis sections, which benefits system efficiency by compensating for a loss in PV efficiency caused by high operating temperature with enhanced electrolysis efficiency, and vice versa for low operating temperature.”
A 78cm2 14.5 percent-efficient CIGS module was placed in thermal contact with the electrolysis apparatus, which has a 100cm2 active surface. The combined PV-electrolyser system’s operating voltage was calculated to be 1.63V. To prevent corrosion and assure long-term stability, nickel plates measuring 1301305mm were utilized to cover the electrolyzer.
With working temperatures ranging from 25 to 50 degrees Celsius and standard sun illumination, the performance of the solar-powered electrolyzer was examined. Built using a 4-cell solar module, the champion device was able to offer an average sun-to-hydrogen (STH) efficiency of 8.5 percent for 100 hours of sustained operation. It had a maximum efficiency of 9.1 percent. The researchers concluded, “The results in this work hold promise for large-scale implementations combining matching integrated PV-electrolysis with stable thin-film PV materials, monolithic design, and exploitation of earth-abundant catalyst components.”
