Pure Nickel Expanded Mesh — Fish Scale Pattern for Hydrogen Electrolyzer Gas Diffusion Layers

Not all electrode meshes should be woven. For hydrogen electrolyzer gas diffusion layers (GDL) and porous transport layers (PTL), expanded nickel mesh — with its characteristic fish scale diamond pattern — offers a fundamentally different set of advantages: no crossing wires to create contact resistance, no weave intersections to trap gas bubbles, and a flat, continuous surface that distributes compression load uniformly across the membrane. At Changzhou DLX Alloy Co., Ltd., we slit and stretch our own pure nickel sheet into expanded mesh in-house — controlling sheet thickness, strand width, long-way diamond (LWD) opening, and final flatness to match your electrolyzer cell design. Full melt-to-mesh traceability on every shipment.

Optimizing for your cell? Send us your target current density, gas production rate per cell, and membrane type. We recommend initial LWD, strand width, and open area — then iterate based on your single-cell test data.

• No wire intersections — uniform electrical contact — Woven mesh creates a contact resistance point at every wire crossing. In a 40-mesh weave, that is 1,600 contact points per square centimeter, each one a micro-ohm of resistance that adds up across the electrode area. Expanded mesh is electrically continuous — the current flows through the strand network without crossing any interfaces. For electrolyzer stacks targeting <1.8 V per cell at 500 mA/cm², eliminating these micro-resistances matters.
• Diamond geometry engineered for gas release — The smooth-walled diamond openings of expanded mesh are shaped by the stretching process — not by the gap between round wires. Hydrogen and oxygen bubbles slide along the strand walls and exit the electrode gap without getting pinned at sharp wire-to-wire corners. This translates to lower bubble overpotential, which becomes the dominant loss mechanism above 300–400 mA/cm².
• Flat surface — uniform membrane compression — Expanded mesh lies flat because it is made from flat sheet. The strands and bonds occupy the same plane. Under stack compression, the load distributes evenly across the membrane surface — no wire knuckle high points that concentrate stress and accelerate membrane thinning over thousands of operating hours.
• Fully annealed — dead flat, no springback — After expansion, the mesh is solution annealed in controlled atmosphere to remove cold work from the slitting and stretching process. The mesh emerges flat and stays flat — it does not curl when you pick it up, it does not spring back when you place it under compression. For automated stack assembly lines using robotic pick-and-place, this predictability is essential.
• Monolithic — cannot unravel at edges — Woven mesh cut to cell frame dimensions leaves exposed wire ends at every cut edge. Under stack compression, these wire ends can shift, protrude, and contact adjacent cells. Expanded mesh has no wire ends — it is one continuous piece of nickel. Cut edges are smooth and stable.
• From our nickel sheet to your mesh — same facility, same quality system — The nickel strip that feeds our expanding press was rolled from our own ingot in our own rolling mill. We control the chemistry, the thickness, the annealing, and the expansion. No subcontractor introduced contamination between the melt and your electrode.

Most expanded mesh on the market begins with purchased nickel sheet — the mesh manufacturer has no control over the chemistry, the rolling history, or the surface condition of the raw material. At DLX, the process starts with our own pure nickel ingots. We hot roll them to strip, cold roll to your specified thickness, slit to the width required by your expanding tooling, and stretch on our expanding press. The entire sequence happens in one facility under one quality system.

Why does this matter for electrolyzer performance? Because the surface chemistry of the nickel sheet — before it ever enters the expanding press — determines the surface chemistry of the finished mesh. If the sheet was contaminated with iron from steel work rolls at a third-party rolling mill, that iron is now embedded in your electrode mesh surface. It will dissolve into the KOH electrolyte over hundreds of operating hours, redeposit on the cathode, and increase the overpotential. We prevent this by doing the rolling ourselves, in a facility where the work rolls only contact nickel alloys.

• 12,000 m² integrated facility — melting, hot rolling, cold rolling, slitting, expanding, annealing, flattening, and inspection. Nickel from ingot to electrode mesh.
• Sheet thickness 0.15–0.50 mm; strand width 0.4–1.2 mm; LWD 1.5–6.0 mm; custom open area 30–65%.
• ISO9001 with full melt-to-mesh traceability; SGS-accredited; BV and TÜV inspection available.

Source: DLX Alloy product catalog. Chemistry certified from ingot to finished mesh.

Third-party inspection by SGS, BV, or TÜV available. Free sample of 5 sheets for first-time electrolyzer OEM evaluation.

It depends on your current density target. Below 300 mA/cm², the difference is marginal — both mesh types perform adequately. Above 350 mA/cm², gas bubble management becomes the dominant loss mechanism, and expanded mesh's smooth-walled diamond openings typically show 15–30 mV lower bubble overpotential than an equivalent woven mesh. We can supply both types — provide your target current density and we will recommend, or we can send sample sheets of each for side-by-side single-cell testing.

Yes. Send us a sample of your current mesh — we will measure the LWD, SWD, strand width, sheet thickness, and open area, then produce expanded mesh to match those parameters in your specified nickel grade. This is a common first step when electrolyzer OEMs are qualifying a second source.

Not at DLX. Our expanding press tooling is made from nickel-compatible materials. This is one of the reasons we brought expanding in-house — third-party expanding shops using standard tool steel dies were introducing iron contamination that showed up in our customers' post-mortem electrode analysis. We eliminated that variable.

Yes. Expanded mesh accepts electrodeposited Raney nickel, thermal spray catalyst coatings, and slurry-coated catalyst layers. Because the strand surface is flat rather than curved as in woven wire, coating thickness uniformity is typically better. The diamond openings are large enough for coating solution to drain cleanly — no bridging or clogging of the openings.

New LWD and strand width combinations require new expanding tooling — typically a slitting die set. Tooling lead time is 3–4 weeks. Once tooled, we produce trial sheets for your evaluation. If the tooling investment is significant, we typically amortize it across the first production order. Contact us with your target mesh parameters and we will provide a tooling feasibility assessment within 48 hours.