Advantages of PEM Water Electrolysis Hydrogen Production Technology

Advantages of PEM Water Electrolysis Hydrogen Production Technology

Hydrogen production by water electrolysis refers to the dissociation of water molecules into oxygen and hydrogen under the action of direct current, which are precipitated  from the anode and cathode of the electrolyzer respectively.

According to the different materials of the electrolyzer diaphragm, hydrogen production by water electrolysis is usually divided into alkaline water electrolysis (ALK), proton exchange membrane (PEM) water electrolysis and high-temperature solid oxide water electrolysis (SOEC). Among them, PEM water electrolysis hydrogen production refers to the hydrogen production process using proton exchange membrane as solid electrolyte and pure water as raw material for electrolysis of water to produce hydrogen. The main components of the PEM water electrolyzer are proton exchange membrane, anode and cathode catalyst layer, cathode and cathode gas diffusion layer, cathode and cathode end plates, etc. from inside to outside. Among them, the diffusion layer, catalyst layer and proton exchange membrane constitute the membrane electrode, which is the main place for material transmission and electrochemical reaction of the entire water electrolyzer. The membrane electrode characteristics and structure directly affect the performance and life of the PEM water electrolyzer.

Compared with traditional alkaline water electrolysis hydrogen production, PEM hydrogen production has the following advantages:

(1)High purity and no pollution PEM hydrogen production uses proton exchange membrane solid electrolyte, the generated gas does not need to be de-alkali treated, and the thickness of the molecular-level microporous ion membrane is very small, which is not easy to produce hydrogen reverse osmosis. The PEM type only requires pure water, no additives, no corrosive liquids, so it does not pollute the environment, and the gas purity is also high; while the traditional alkaline electrolyte needs to add 15% NaOH or 30% KOH, so the electrolyte is highly corrosive and easy to produce flushing liquid to contaminate the load pipeline.

(2)High conversion efficiency. The PEM type catalytic electrode is a molecular-level microporous electrode that is tightly attached to both sides of the ion membrane and its internal pores. It is a zero-distance catalytic electrode with the advantages of large reaction area and high conversion efficiency. However, the traditional alkaline electrodes are limited by a small distance, and the inter-electrode resistance is large, which leads to larger current, high heat generation, and low conversion efficiency.

(3)Light weight and small size. The collector structure of the two-stage chamber in the PEM type electrolyzer is compact and flexible, making the electrolyzer light weight and small size. The weight is only 1/3 of that of an ordinary electrolyzer with the same hydrogen production. The advantages are zero inter-electrode distance and small internal resistance of the cell. The collector in the electrode chamber of a traditional alkaline electrolyzer is not elastic, resulting in high heat loss of electric energy and low conversion efficiency.

(4) Adaptable to the volatility of renewable energy generation

The PEM water electrolysis hydrogen production system has a fast response speed and adapts to dynamic operation, which is very suitable for the uneven, intermittent and volatile transmission of renewable energy such as wind and solar energy.

From a technical perspective, the electrolytic cell it uses is compact in structure, small in size, and conducive to rapid load changes. The electrolytic cell has high efficiency, high gas purity, low energy consumption, and greatly improved safety and reliability, which is more suitable for the volatility of renewable energy. Therefore, PEM water  electrolysis technology is hailed as one of the most promising water electrolysis hydrogen production technologies in the field of hydrogen production.

However, since PEM electrolyzers need to operate in a highly acidic and oxidizing working environment, the equipment relies more on expensive metal materials such as iridium, platinum, and titanium, resulting in excessively high costs. This is also the bottleneck restricting the development of PEM hydrogen production technology and the direction of research and development.