Towards the Hydrogen Economy-A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers

Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. This review examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis. This process is far from being new, but research shows that there is still plenty of room for improvement. The efficiency of an electrolyzer mainly relates to the overpotential and resistances in the cell. This work shows that the path to better electrolyzer efficiency is through the optimization of the cell components and operating conditions. Following a brief introduction to the thermodynamics and kinetics of water electrolysis, the most recent developments on several parameters (e.g., electrocatalysts, electrolyte composition, separator, interelectrode distance) are highlighted.

Automated summary

Environmental concerns have made the search for cleaner energy sources a top priority worldwide. Hydrogen, with its high energy content, is a well-known energy carrier, but the efficiency of its production through electrolysis, particularly alkaline water electrolysis, still has room for improvement. Optimizing cell components and operating conditions is key to enhancing electrolyzer efficiency.