EXSOLUTION-BASED NANOPARTICLES FOR LOWEST COST GREEN HYDROGEN VIA ELECTROLYSIS

Today’s alkaline electrolysers favour current densities over efficiency: to achieve commercially relevant current densities, these systems typically operate at voltages exceeding 2 V/cell, corresponding to electrolyser power consumption of >54 kWh/kg. There are four reasons for employing high voltages: 1) electrodes’ insufficient electrochemical activity, 2) the relatively high gas permeability of commonly employed diaphragms means that improved hydrogen purity can be achieved at high current operation points, 3) the stack designs are not optimised for low-current operation due to very simple flow fields, and 4) high currents are required to achieve attractive electrolyser CAPEX costs (EUR/kW).
Yet, there is a growing consensus that the wider adoption of green H2 is not hindered by electrolyser CAPEX: the costs of green H2 are in most cases vastly dominated by OPEX, which in turn is a direct function of electrolyser efficiency. Thus, to achieve lowest possible levelised cost of H2, efficiency should be prioritised over current density.

EXSOTHyC will optimise electrolyser operation towards lower voltages and higher efficiencies. The innovation is three-fold and addressing all four above-mentioned reasons:
• Alternative pathways to the O2 and H2 evolution reactions by new anode and cathode approaches
• Novel concepts of membrane electrode assemblies with integrated components
• Novel cell design to enhance overall cell efficiency by integrating disruptive concepts

In the project, we adopt an approach combining computer simulations, rapid prototyping, and thorough experimental validation on single cell, SRU and short stack level. In a nutshell, we will combine electrodes made using powder metallurgy with ceramic nanoparticles fabricated by exsolution, leveraging on the synergy that both methods require reducing atmospheres. Also, membrane-electrode assemblies based on Zirfon will be developed. The cell/stack will be backed by computer modelling.