Neovolt gave a presentation at the 3rd International Conference on Electrolysis (ICE) 2021, held in Golden, Colorado in June 2022. The conference offered a four-day setting for the discussion on all things water electrolysis. Neovolt explicated the need for comprehensive measurement of electrical quantities in industrial water electrolysis systems. Limited and often aggregated values for voltage and current lead to loss of information on active and reactive power flows, fluctuation of the electrolyser loading even under normal steady-state operation, and condition of both the power supply and the electrochemical reactor. Verification of the performance of electrolytic hydrogen production is what Neovolt does best.
Proton exchange membranes (PEM)
Overall, the international conference on electrolysis focused heavily on single cell development. Many companies continue to believe in the proton exchange membrane (PEM) technology even though its acidic operating environment necessitates the use of platinum group metals (PGM), notably Ir and Pt. Experts predict that the Ir loading would decrease, and current densities would increase so much that the limited Ir supply would enable the scale-up of the PEM technology—recycling of Ir is also expected to catch up.
Anion exchange membranes (AEM)
The alkaline environment is still of strong interest to avoid the use of PGMs. Anion exchange membrane (AEM) technology seeks durable catalysts, electrodes, membranes, and ionomers. AEMs can deploy KOH with a low concentration. Moreover, there are efforts to exclude KOH altogether. The use of DI water should improve cell durability, since many AEMs are unfortunately unstable in an alkaline environment. Performance is still a major problem without the extra conductivity from KOH.
Ion-solvating membranes (ISM)
The latest electrolysis technology development for the alkaline environment are the ion-solvating membranes (ISM). The ISM is the first alkaline technology to use non-porous, dense membranes which can be far thinner than in traditional alkaline electrolysers. The membranes swell with aqueous KOH—concentrations closer to traditional alkaline—which should emphasize the cell performance. Hence, the ISM cells should have low resistance and low gas crossover. Unlike AEMs, ISMs do not require the ionomer in electrodes. Development of a robust and durable membrane for the ISM technology requires further research.
Solid oxide electrolysis (SOE)
Traditional alkaline technology is still the workhorse to answer to the massive need for electrolytic hydrogen. However, development efforts in solid oxide electrolysis (SOE) technology, which is steam electrolysis at temperatures closer to 1000 °C, may bring SOE electrolysers to the MW-scale very soon.
Proton ceramic electrolysis (PCE)
Yet, there’s another technology being developed for the temperature range between the low temperature water electrolysis (< 100 °C) and the SOE. Proton ceramic electrolysers (PCE) inhabit the intermediate temperature range of 400–600 °C. Interestingly for the green transition, it is thermochemically possible to operate PCEs not only as reversible hydrogen electrolysis/fuel cells but also as ammonia and methane synthesis/fuel cells. First planar and tubular design PCE stacks are now being tested!
Summary
Traditional alkaline and PEM are already available to answer the enormous scale-up need in electrolytic hydrogen production capacity. Neovolt focuses on continuously safe and efficient operation of industrial-scale electrolysers and their integration through power electronics to the electricity grid. We are eager to see how ICE aims to control climate change!
Joonas Koponen, CTO 
