PEM Electrolyzed Water
Green hydrogen is to generate electricity through renewable energy, and then obtain hydrogen through electrolysis of water. Hydrogen production by electrolysis of water is to decompose water molecules into hydrogen and oxygen through an electrochemical process under the action of direct current, which are separated out at the cathode and anode respectively. At present, there are three main technical routes for hydrogen production by electrolysis of water, namely alkaline electrolysis (AWE), proton exchange membrane (PEM) electrolysis and solid oxide (SOEC) three technical routes.
Among the above three technical routes, PEM electrolysis of water has higher efficiency and is suitable for the volatility of renewable energy power generation. Let’s take a look at the technical principle of PEM electrolysis of water to produce hydrogen.
Compared with the alkaline electrolytic cell, the PEM electrolytic cell replaces the asbestos membrane with a proton exchange membrane, conducts protons, and isolates the gas on both sides of the electrode, avoiding the shortcomings of the alkaline electrolyte. At the same time, the volume of the PEM electrolytic cell is more compact and the structure has zero gap, which greatly reduces the ohmic internal resistance of the electrolytic cell and improves the overall performance.
A typical PEM cell is mainly composed of anode end plates, cathode end plates, cathode and anode diffusion layers, cathode and anode catalytic layers, and proton exchange membranes. Among them, the role of the end plate is to fix the electrolytic cell components, and guide the current transfer, distribute water and gas, the diffusion layer plays the role of collecting current, promoting gas-liquid transfer, etc. The core of the catalytic layer is composed of catalyst, electron conduction medium, proton conduction medium The three-phase interface is the core site of the electrochemical reaction.
The proton exchange membrane generally uses a perfluorosulfonic acid membrane to transfer protons, isolate the gas generated by the cathode and anode, and prevent the transfer of electrons.
Advantages of PEM water electrolysis technology
Compared with alkaline electrolyzed water, the advantages of PEM electrolyzed water are mainly:
1. Since the proton exchange membrane solid electrolyte is used, the generated gas does not need to be dealkalized;
2. The efficiency is higher than that of alkaline electrolytic cells;
3. Quick start and stop, good responsiveness
4. It can adapt to the volatility of renewable energy generation.
Disadvantages of PEM water electrolysis technology
The disadvantage of the current PEM water electrolysis technology is the high cost, mainly because the catalyst uses the precious metal platinum, and it is difficult to reduce the cost temporarily. This is the same as the problem faced by the fuel cell. How to reduce the platinum loading of the catalyst or find new low The cost of substitute materials is also a key technical problem to be researched and overcome at present.
Our company’s ultrasonic spraying equipment can be sprayed on a variety of different metal alloys, including the preparation of platinum, nickel, iridium and ruthenium-based fuel cell catalyst coatings, as well as PEMs, GDLs, DMFCs (direct methanol fuel cells) and SOFCs (solid Oxide fuel cell) manufacturing. The battery manufactured by this technology has the characteristics of high battery load and high battery efficiency.
