A photo-thermo-electrochemical cell for efficient solar fuel and power production

Seeking a promising route for efficient conversion of solar energy into electricity or fuel for energy storage is important for addressing the intermittent nature of solar energy sources. Here we report a photo-thermo-electrochemical cell (PTEC) that utilizes two high-temperature solid oxide-based cells working at different high temperatures for flexible electricity generation and hydrogen production for energy storage. The electricity and hydrogen production modes can be switched by introducing a voltage difference or current difference with or without a DC-DC converter. Optimized heat recovery can achieve a solar-to-electricity efficiency and solar-to-hydrogen efficiency of 10.45% and 9.92%, respectively. The energy storage capability can be as high as 1.05. Engineering better catalysts and higher conducting electrolytes can further increase the solar-to-electricity and solar-to-hydrogen efficiency. This PTEC opens a promising way for the efficient use of solar energy and for flexible electricity and fuel generation.