Hydrogen can be used as an energy vector for renewable energies such as solar or wind by using water electrolysis systems [1]. Commercially, it can be electrochemically produced by alkaline and proton exchange membrane (PEM) electrolysis, at which the investment cost of the later is presently almost three times higher than the alkaline technology [2]. However, the main advantage of PEM electrolysers is the possibility to operate at much higher current densities with a significant potential for cost reduction owing to the compact design [3]. An open question is still the life time of the membrane electrode assembly (MEA) of the PEM electrolyser operating at high performance. In this work rainbow stacks with MEAs from different suppliers are tested in a 20 kW PEM electrolyser (2.5 N m³ H₂ h^-1) operating constantly and dynamically up to 5 A cm^-2. The 120 cm² active area MEAs have membranes with the same thickness but different Ir-based catalyst loadings. Operating the electrolyser at low current densities has an impact in the H₂ crossover. The most durable MEAs do not experience any lost in performance after more than 3000 h of operation under stationary and dynamic regimes. Post-mortem characterisation and water analysis are carried out to determine the degradation mechanism of the rest of the MEAs.

References

[1]         A. Sternberg, A. Bardow, Energy Environ. Sci. (2015) 389.

[2]         Fuel Cells and Hydrogen Joint Undertaking, Report: Commercialisation of Energy Storage in Europe, 2015.

[3]         M. Carmo, D.L. Fritz, J. Mergel, D. Stolten, Int. J. Hydrogen Energy 38 (2013) 4901.