The Short Answer
Nickel foam is a porous, open-cell nickel material used as the electrode substrate, catalyst support and porous transport layer in alkaline (AWE) and anion exchange membrane (AEM) water electrolyzers. Nickel is conductive, affordable and stable in the hot, concentrated alkaline electrolyte these systems use. The foam structure adds a large three-dimensional surface for catalyst loading and open channels that let hydrogen and oxygen bubbles leave the surface quickly. It is not used in PEM electrolyzers, whose acidic environment requires titanium.
Industrial alkaline electrolyzers run in 25–30 wt.% KOH or NaOH and rely on porous nickel electrodes such as Raney nickel or nickel foam (Petkucheva et al., 2025). In AEM electrolysis, nickel-based porous transport layers are widely used for their alkaline stability, conductivity and gas and electrolyte transport (Park et al., 2026).
Why Nickel Foam Works in Electrolyzers
An electrolyzer electrode has three jobs at once: conduct current, host the reaction, and get the gas out of the way. Nickel foam does all three in one part.
Conductivity and stability. Nickel conducts electricity well and resists corrosion in the alkaline electrolyte, so the electrode keeps its structure over long operation without platinum-group metals.
Surface area. The three-dimensional strut network offers far more surface per square centimetre of cell area than a flat plate or a single mesh, which means more room for catalyst and more active sites.
Bubble release. At high current density, gas bubbles that cling to the electrode block the reaction and raise cell voltage. Open, interconnected pores give bubbles a path out and let fresh electrolyte back in.
Ready to modify. Nickel foam is easy to coat, etch or electroplate. Research groups routinely turn plain nickel foam into a high-activity anode with simple treatments: one 2026 study etched nickel foam in FeCl3 to form a nickel-iron oxyhydroxide surface and reached an overpotential of about 255 mV at 10 mA/cm², running 50 hours as an AEM anode.
Where Nickel Foam Sits in the Stack
| Electrolyzer type | Role of nickel foam | Why nickel |
|---|---|---|
| Alkaline (AWE), zero-gap | Anode and cathode substrate pressed against the diaphragm; catalyst support | Stable in 25–30 wt.% KOH; low cost at large electrode areas |
| Anion exchange membrane (AEM) | Porous transport layer (PTL) and catalyst support | Designed for nickel-based, platinum-free catalysts; alkaline-stable |
| PEM | Not used | Acidic conditions corrode nickel; titanium PTLs are standard |
| R&D and pilot cells | Standard substrate for HER and OER catalyst development | Easy to cut, coat and test; widely used as a baseline |
2026 Market Context: Why Supply Matters Now
According to the IEA, installed electrolysis capacity doubled in 2025 to more than 4 GW, and more than 2.5 GW was under construction for operation in 2026. At the same time the IEA describes electrolyser manufacturing as entering a consolidation phase, with some manufacturers struggling after aggressive price competition.
For stack builders this creates a practical risk: electrode materials must be available in consistent quality at production volumes, from suppliers that will still be there in five years. A material that performs well in a lab cell is only useful if the same pore structure, thickness and cleanliness arrive on every roll.
Can you hold thickness and areal density within tolerance across rolls, not just samples? Can you provide a material certificate with every lot? Can you commit to annual volumes and lead times? Can you show factory documentation to a qualified buyer?
Specifications That Decide Stack Performance
Nickel foam is not a single product. These are the parameters to agree with your supplier before a pilot, and to hold constant when you scale.
| Parameter | Why it matters in an electrolyzer | What to specify |
|---|---|---|
| Nickel purity | Impurities can dissolve, poison catalysts or foul membranes | Minimum purity and a lot certificate |
| Pore size (PPI) | Finer pores add surface area; coarser pores release bubbles more easily | Nominal PPI and allowed range |
| Porosity | Balances electrolyte access and gas escape against conductivity | Target porosity range |
| Thickness and tolerance | Sets compression and contact pressure in zero-gap and AEM cells | Nominal thickness plus tolerance; how it is measured |
| Areal density (g/m²) | Controls the amount of nickel, cost and mechanical strength | Target g/m² and tolerance per roll |
| Compressed thickness | Foam is squeezed during stack assembly; this decides final contact | Test method and pressure for measurement |
| Surface cleanliness | Oils or residues block catalyst adhesion and active sites | Cleaning condition on delivery |
| Format | Affects yield and automation of electrode cutting | Sheet size or roll width, die-cut shapes |
Nickel Foam vs Other Nickel Electrode Formats
Nickel mesh and expanded nickel are stiff and simple, but offer much less surface area than foam. They are common as backing or current distributors.
Nickel felt and fibre PTLs give fine, uniform contact against a membrane, and are often paired with or compared against foam in AEM cells.
Sintered nickel powder gives very fine porosity but lower open volume for bubbles and is heavier per unit area.
Nickel foam sits in the middle: high open porosity for gas release, large surface for catalyst, light weight, and easy cutting from rolls. Many stack designs combine layers, for example a foam against the membrane side and a mesh or plate behind it.
Sourcing Nickel Foam From PrometheanFoam
PrometheanFoam supplies nickel foam in sheets, rolls and custom die-cut sizes from one of the largest non-aluminum metal foam production bases, with ISO 9001:2015 certified mass production and guaranteed supply. We work with electrolyzer developers from lab cells to pilot stacks.
Custom PPI, thickness from 0.3 mm and custom alloys, including nickel-iron and nickel-copper, are available. Every order ships with material certificates, and factory audit documentation is available to qualified buyers under NDA.