Progress and Prospects of Solid Alkaline Water Electrolysis Technology Using Anion Exchange Membranes

Abstract

Hydrogen is an important media to convert unstable renewable energy to stable and transportable energy substances. Water electrolysis is a major technology to produce low-cost large amounts of hydrogen. Solid alkaline water electrolysis using an anion exchange membrane has recently attracted significant attention as an efficient hydrogen production system without using noble metals in rapid response to fluctuating and unstable electric power generated from solar and wind power energies. The development of this system has been however long limited due to the lack of stable membranes in alkaline conditions. In addition, not only using high-performance membrane and catalyst materials, but also membrane–electrode assemblies (MEAs) should be taken into account for obtaining high-performance and durable water electrolysis cell system. Based on the systematic material design, we first clarified the degradation mechanism of conventional membranes and succeeded in developing highly durable anion exchange membranes under high temperature and alkaline conditions. Then, high-performance and durable MEAs using our developed membranes have been demonstrated at the water electrolysis operations not only in alkaline solutions but also in pure water. These achievements are breakthrough technologies that will greatly advance the research of solid alkaline water electrolysis for realizing a global hydrogen energy society.