Advances in water electrolysis technology with emphasis on use of the solid polymer electrolyte

Abstract

Efforts to improve water electrolysis technology are being made using three promising approaches: (a) development of solid polymer electrolyte (SPE) water electrolysers, (b) increasing the operating temperature of alkaline water electrolysers from 80° C to a temperature in the range 120–150° C, and (c) investigation of advanced concepts. The research and development efforts on SPE water electrolysers are aimed at (a) low cost current collectors, (b) high-activity electrocatalysts, (c) high temperature capability, (d) low cost SPE, and (e) design and construction of scaled-up cell stacks. Attempts are being made to find materials for cells and auxiliaries which are stable in an alkaline environment at elevated temperatures. Advanced concepts for electrolytic hydrogen production, including (a) finding better reversible electrocatalysts, (b) use of anode depolarizers, (c) water vapour electrolysis in molten or solid electrolytes, (d) development of hydroxyl ion transporting membranes, (e) investigation of thermochemical-electrochemical hybrid cycles, and (f) photoelectrolysis of water, are still at a preliminary research stage.