The Hard Part Begins After The Lab Experiments End · Rochan Sinha

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Bridging the "valley-of-death" for advanced materials for electrolysis

Recently, I got a chance to present the work we are doing at the 249th ECS meeting in Seattle. The depth and breadth of research being presented there always surprises me. However, there was one aspect of the conference which left me with mixed feelings. Most presentations on electrocatalysts for water electrolysis were about novel materials tested at lab scale under ambient conditions. This is valuable fundamental work, but it's only part of the story. Very few presentations addressed what happens when you have to scale up these materials and test them in a real electrolyzer stack.

As alkaline electrolyzer capacity scales from megawatts to gigawatts, catalyst performance and durability are turning from lab metrics into a test of whether the project will pass Final Investment Decision (FID). Green-hydrogen plants are financed on multi-year off-take agreements that assume the stack will maintain its efficiency for 10-15 years, and any drastic reduction in efficiency can derail a viable project. Therefore, it is not enough for a novel catalyst material to just show high performance at the start of operations. It also needs to be stable enough to survive for the lifetime of the plant. This is the often-talked-about "valley-of-death" for advanced materials or any new technology which needs to be scaled from TRL 2-3 to TRL 7-8.

This is a problem we think about every day at Newtrace. We deal with the challenges of developing best-in-class catalysts and scaling them from cm2 to m2 scales. These advanced materials not only need to demonstrate high efficiency but also need to survive for the lifetime of a commercial electrolyzer plant. The gap between what works in the lab and what survives in industrial conditions is the central challenge of our work.

The first gap between studies done in the lab and those needed to be successful at industrial scale is the catalyst deposition process. A catalyst coating optimised on a 1 cm2 coupon behaves very differently when deposited on a 10,000 cm2 electrode. At these scales, material properties are much harder to reproduce. Uniformity across the substrate becomes difficult to achieve. Repeatability across batches drops. Much of this comes down to complex, interdependent process parameters that become difficult to control at production scale.

The preparation and treatment of the substrate also starts to play a role. At lab scale, you can prepare and clean a small coupon to near-ideal conditions. At production scale, pre-treatment of the substrate is its own engineering problem: surface consistency and cleanliness both affect how the coating adheres and whether it will finally survive or not. A coating process that works reliably on a coupon will show inconsistent results on a full-size electrode if the substrate pre-treatment processes aren't controlled to the same standard as the coating process itself.

Solving these problems takes quality control and process engineering, and both depend on material-property data to understand why the coating behaves as it does at scale, the 'process-material-electrochemistry trifecta' as I like to call it.11More on this in a future post. Understanding this trifecta is where deep expertise in electrochemistry and materials characterisation becomes essential — along with the ability to analyse large volumes of process data.

The second gap is between lab testing conditions and real-world operations. A typical lab-scale electrocatalyst test runs in a glass beaker with a standard reference electrode in 1M KOH at ambient conditions. Compare that to an actual commercial alkaline electrolyzer: a bipolar stack running at 80–90°C, in 30–32 wt% KOH, at 16 barg. These industrially relevant conditions usually lead to better short-term performance improvements but affect the long-term stability of the catalyst-coated electrodes, leading to early failure, even though the same material showed great promise at lab scale.

For example, higher temperature lowers the overpotential and improves cell efficiency, but affects the stability of various stack components including the catalyst layer.22Lohmann-Richters et al., reports cell-voltage reductions of 3.4-4 mV/K between 100 and 200°C, set against accelerated degradation of catalysts, diaphragms, and other components in the more corrosive high-temperature electrolyte. For the 60-90°C range typical of commercial operation, Zeng et al. document the same fall in cell voltage with rising temperature. Higher KOH concentration reduces ohmic losses and lowers cell voltage, but is far more corrosive.33Gilliam et al., reported that specific conductivity rises with KOH concentration to a maximum that depends on temperature — near 20 wt% at room temperature, shifting toward ~32 wt% at 80-90°C. Higher operating pressure leads to reduced bubble-related...