Hydrogen production by electrolysis of water refers to the dissociation of water molecules under the action of direct current to generate oxygen and hydrogen, which are separated from the anode and cathode of the electrolytic cell respectively. On the technical level, electrolysis of water for hydrogen production is mainly divided into alkaline hydrolysations (AWE), solid polymer PEM, solid polymer anion exchange membrane (AEM) and solid oxide (SOE). Among them, AWE is an early industrialized hydroelectricity solution technology with decades of application experience and relatively mature technology. In recent years, PEM hydropower generation technology has developed rapidly in industrialization, SOE hydropower generation technology is in the preliminary demonstration stage, and AEM hydropower generation research has just started.

1. Alkaline electrolysis of water to produce hydrogen

The diaphragm of electrolytic water hydrogen production tank is mainly made of non-asbestos material, which plays a role in gas separation. The electrolyte of industrial alkaline water electrolytic cell usually uses potassium hydroxide solution with mass fraction of 20%~30%, the operating temperature of electrolytic cell is 70~80, the working current density is about 0.25 ampere/cm2, the gas pressure is 0.1 ~ 1.6 mpa, and the total efficiency is 62%~82%. Hydrogen production from alkali water is a mature technology with low cost of investment and operation, but it has some problems such as alkali loss, corrosion and high energy consumption.

2. Pure water electrolysis of water to produce hydrogen

Different from electrolytic water hydrogen production, proton exchange membrane (PEM) electrolytic water hydrogen production uses perfluorosulfonate proton exchange membrane with good chemical stability, proton conductivity and gas separation to replace non-asbestos diaphragm as solid electrolyte, which can effectively prevent electron transfer and improve the safety of electrolytic cell.

High temperature solid oxide electrolysis of water to produce hydrogen

High temperature solid oxide electrolysis of water for hydrogen production is different from alkaline and PEM electrolysis. High temperature solid oxide electrolysis of water for hydrogen production uses solid oxide as electrolyte material, and the working temperature is 800~1 000. The electrochemical performance and efficiency of hydrogen production process are significantly improved.