Why are nickel-based materials preferred for electrodes in alkaline water electrolyzers? The Economic & Technical Edge

Nickel-based materials are the preferred choice for electrodes in alkaline water electrolyzers because they offer the most effective balance between durability and performance in harsh chemical environments. Nickel exhibits exceptional resistance to corrosion in highly alkaline solutions while maintaining favorable electrocatalytic activity, which lowers the energy required to split water. Additionally, its abundance and low cost compared to precious metals make it the only economically viable option for large-scale hydrogen production.

While noble metals may offer marginal performance gains, nickel-based materials provide the critical intersection of high conductivity, chemical stability, and economic scalability necessary for industrial electrolysis.

The Technical Superiority of Nickel

Unmatched Corrosion Resistance

The environment inside an alkaline electrolyzer is chemically aggressive. Nickel distinguishes itself by resisting degradation in these high-pH conditions. This stability ensures the electrode maintains its structural integrity over long operational lifespans.

Favorable Electrocatalytic Activity

To produce hydrogen efficiently, the electrode must lower the energy barrier of the reaction. Nickel provides naturally favorable electrocatalytic activity, facilitating the reaction better than most other transition metals. This inherent property reduces the voltage required to drive the process.

Low Overpotential

Overpotential represents the wasted energy in an electrochemical system. Nickel-based electrodes exhibit a relatively low overpotential, meaning more of the input electricity is converted directly into chemical energy (hydrogen). This efficiency is critical for keeping operational costs down.

Engineering for Maximum Efficiency

Increasing Active Sites

Raw material properties are only half the equation; structural engineering plays a major role. By preparing nickel as alloys or applying specific coatings, engineers can create high surface area structures. This maximizes the number of "active sites" where the chemical reaction can occur.

Enhancing Reaction Rates

A higher surface area directly translates to faster reaction kinetics. This structural enhancement significantly boosts the efficiency of both the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER). The result is a higher hydrogen yield per unit of power applied.

Synergy with Precious Metals

While nickel is the foundation, it acts as an excellent substrate for further enhancement. As noted in supplementary data, adding trace amounts of precious metals like platinum can further lower activation energy. These composites leverage nickel's bulk conductivity while utilizing the superior catalytic properties of noble metals.

Understanding the Trade-offs

The Performance Gap

While nickel is excellent, it is not chemically perfect. Pure precious metals (like platinum) still theoretically offer lower activation energies for the Hydrogen Evolution Reaction (HER). Reliance solely on nickel requires careful surface engineering to compete with the raw efficiency of noble metals.

Complexity of Manufacturing

To achieve the "high surface area" mentioned, simple nickel sheets are often insufficient. Manufacturers must utilize advanced techniques to create porous coatings or alloys. This adds a layer of complexity to the fabrication process compared to using solid metal plates.

Making the Right Choice for Your Project

When selecting electrode materials for alkaline electrolysis, your specific constraints will dictate the final composition.

• If your primary focus is Cost-Efficiency: Prioritize pure nickel or nickel-iron alloys to maximize durability and minimize capital expenditure without relying on volatile precious metal markets.
• If your primary focus is Maximum Output: Consider nickel-based composite electrodes sprayed with trace platinum to reduce overpotential and maximize hydrogen yield per kilowatt-hour.

Nickel remains the definitive standard for robust, scalable, and economically sound hydrogen production.

Summary Table:

Feature	Nickel-Based Electrodes	Benefit to Electrolysis
Corrosion Resistance	Exceptional in high-pH environments	Long-term structural integrity and durability
Catalytic Activity	Naturally high for HER and OER	Lower energy barrier for splitting water
Energy Efficiency	Low overpotential	Reduced voltage requirements and operational costs
Economic Value	Abundant and low-cost	Enables scalable, industrial hydrogen production
Surface Engineering	High surface area (alloys/coatings)	Maximized active sites for faster reaction rates

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References

1. Diogo M.F. Santos, José L. Figueiredo. Hydrogen production by alkaline water electrolysis. DOI: 10.1590/s0100-40422013000800017

This article is also based on technical information from Kintek Solution Knowledge Base .