Photovoltaic-Electrolyzer System Operated at >50 mA cm-2 by Combining Large-Area Shingled Silicon Photovoltaic Module with High Surface Area Nickel Electrodes for Low-Cost Green H-2 Generation

Abstract

Green hydrogen plays an important role in the energy transition as a renewable energy vector for long-duration energy storage and as feedstock chemical for the industry. To reduce the price below 1.5 euro kg(-1) H-2, competitive to production from fossil fuels, silicon photovoltaic (PV)-powered efficient anion-exchange membrane (AEM) water electrolysis is a promising combination. Practical implementation of such a photovoltaic-electrolyzer (PV-EC) technology requires standard area-sized solar cells and electrolyzers operating at large current densities. Nonetheless, state-of-the-art research often employs <10 cm(2) PV devices and electrolyzers operated at <10 mA cm(-2). Herein, a commercially relevant PV-EC system combining shingled standard silicon technology with efficient low-cost AEM electrolysis using high-surface-area (26 m(2) cm(-3)) nickel nanomesh electrodes is presented. The produced H-2, operating current, and voltage are in situ monitored over >20 h yielding a stable solar-to-hydrogen efficiency (eta(STH)) of 10% at electrolyzer current densities approximate to 60 mA cm(-2) and dynamic load testing up to 300 mA cm(-2) results in stable performance. Based on the measured PV-EC system data, best practices to accurately determine the eta(STH) for PV-powered water-splitting devices and the validation of this benchmark against important component parameters for practical implementation of this technology are discussed.