Abstract:

By reducing carbon dioxide emissions in the fields of transportation and industry, hydrogen generation from water electrolysis using renewable energy is a key technical avenue to attaining green and sustainable development. Renewable energy exhibits intermittent properties, with photovoltaic power exhibiting a relatively periodic output variation and wind power exhibiting a random fluctuation. The alkaline water electrolyzer and proton exchange membrane water electrolyzer performance and material degradation mechanisms under fluctuating power input are reviewed in this research. For the alkaline water electrolyzer, when the fluctuation power change is below the minute level, the electrolyzer cannot respond in time, thereby preventing the reaction balance and heat balance from being established, which may lead to the phenomenon of electrode catalyst dissolution and aggregation, diaphragm mechanical damage, electrolyte precipitation blocking reaction channel, etc., making the performance of the electrolytic cell decay. In a proton exchange membrane water electrolyzer, the fluctuation of power supply leads to the dissolution, migration, deposition, and aggregation of anode catalyst; the membrane degrades due to the attack of the local hot spot and hydroxyl free radical, and the dissolution and oxidation corrosion of the bipolar plate leads to the degradation of the electrolyzer performance. The ability of the electrolyzer to resist the fluctuation of power supply can be improved by studying mitigation strategies based on the influence rule of fluctuation on the operating condition, material, structure, and performance of the electrolyzer. This will increase the utilization rate of renewable energy, which is crucial to lowering the cost of hydrogen production from electrolytic water and promoting its widespread application.

Key words: power supply fluctuations, electrolysis of water to produce hydrogen, catalyst, proton exchange membrane, bipolar plates