December 2, 2024
Production of Nickel Mesh Electrodes for Alkaline Electrolyzers
A wide range of electrode catalysts is optional for hydrogen production by way of alkaline water electrolysis, including precious metal-based catalysts (e.g., platinum, palladium, gold, silver, etc.) and nonprecious metal-based catalysts (e.g., iron, cobalt, nickel, etc.), as well as nonmetal-based catalysts (e.g., carbon materials). Electrode is a key factor in improving hydrogen production efficiency and reducing costs. In this article, we’ll dive into the production of currently most used nickel mesh electrodes.
The Importance of Electrode Catalysts
Electrodes play a crucial role in hydrogen production electrolyzer, where electrochemical reactions take place, and the core area for hydrogen generation lies. That’s because an efficient electrode can reduce energy consumption and increase the production rate of hydrogen. The overall performance and economic efficiency of the hydrogen production system can be effectively improved through electrode design and material selection.
Although there are various materials for electrodes, the presently popular electrodes for alkaline water electrolysis hydrogen production are usually nickel-based. That’s because nickel is resistant to high temperatures, alkali corrosion, and relatively low cost. Commonly used nickel-based electrodes include nickel mesh electrodes and nickel foams. In the following section, we’ll focus on the production of the most widely used electrodes: nickel mesh electrode coated with Raney nickel.
Production of Nickel Mesh Electrodes
The main production process of the electrode is presented as follows:
Step 1 Wire Drawing
The process of wire drawing is mainly to draw nickel several times through the wire drawing machine, gradually reducing the diameter until the desired nickel wire size is reached, and then the qualified nickel wire is rolled or plated for easy transport and storage. The commonly used diameter of nickel wire for electrode is about 0.25mm.
Step 2 Weaving
This step is to weave the drawn nickel wire into a mesh structure through the weaving machine. Weaving methods include plain weave, twill weave, etc. The electrodes generally use 40-80 mesh nickel mesh.
The “mesh” here refers to the number of holes per inch screen, 50 mesh means 50 holes per inch, 200 mesh is 200, the higher the mesh number, the more holes.
Step 3 Spraying Raney Nickel
Raney Nickel is an alloy of nickel and aluminium, which is made into a porous catalyst by a specific chemical treatment. Preparation of Raney Nickel typically involves fusing nickel and aluminium in a ratio to form an alloy, which is then quenched and crushed to obtain fine particles. Generally 80/20 Raney nickel is used, i.e. 80% nickel, 20% aluminium.
The process of spraying is to use some kind of heat source (e.g. plasma arc, combustion flame, etc.) to heat the nickel-aluminium alloy powder to a molten or semi-molten state, and these molten or semi-molten particles are pushed by a high-speed airflow to hit the surface of the pre-treated nickel mesh.
Due to the high temperature and speed, particles are then flattened and solidified to form a mechanical and metallurgical bond with the nickel mesh surface. During the spraying process, precise control of the spraying parameters, such as spraying distance, spraying angle, spraying speed, etc., is required to ensure the quality and performance of the coating. Typical coating thicknesses are 240g/m²-300g/m².
Step 4 Activation Treatment
When the Raney nickel is sprayed on the nickel mesh, the high content of nickel and the low content of aluminium ensure that the nickel in the molten state Raney nickel can be effectively bonded to the mesh. Aluminium in the Raney nickel will then randomly appear on the sprayed coating.
At this stage, it is necessary to activate the sprayed nickel mesh with a sodium hydroxide solution. The so-called activation treatment is to react away the aluminium in the Raney nickel. As the activation treatment goes, the surface of the coating presents a pitted pattern, which greatly increases the specific surface area of the electrode and thus improves the electrolysis efficiency.
Step 5 Application
The activated nickel mesh electrodes can then be rounded to the required size and welded to the electrolyser plates for further use.
As a professional nickel wire mesh factory, NHGT has the art of state plasma spraying equipment for excellent coating treatment on nickel meshes. If you are looking for a reliable nickel mesh supplier, just contact our team at info@nickelgreen.com or call us directly at +86 132 31116517 for urgent demand. We will reach out to you within 24 hours.
1 Comment
MohammadDecember 2, 2024
Hi Madam/Sir,
Can you please provide a quotation for 430 mm diameter Ni mesh as well as ready made electrode of the same size.
With Regards
Dr. M. Shadab Siddiqui
Manager
Surface Coatings and Treatment (SCT)
BHEL R&D Hyderabad
9654465082
