Innovative proton conducting ceramic electrolysis cells and stacks for intermediate temperature hydrogen production

PCCEL stack technology in Europe is largely based on tubular cell design enabling pressurised operation up to 10 bar at 600°C, as demonstrated in the WINNER and GAMER projects, while recent work published in the literature also addresses planar cell and stack development. The state-of-the-art cells consist of traditional Ni-cermet electrode, BaZr_1-x-yCe_xY_yO_3-d based electrolyte, and composite electrodes containing Co and various rare earth elements, exhibiting current density peaking at 0.3 A/cm² at 600°C at thermoneutral voltage. The topic focuses on the development of new cell and stack designs aiming at improving the performance and flexibility of operation, while reducing costly ceramic-based components and critical raw materials and strategic raw materials (e.g. light and heavy rare earth materials, LREE and HREE, Ni, Co) https://www.crmalliance.eu/hrees. Improved thermal and load cycling capabilities (faster and higher number of thermal cycles) should be ensured by designing new cells and/or stacks, e.g. electrode or metal supported cells/stacks, cells with integrated interconnect/current collector/electrode, metal-based monolith cells/stacks, etc. This can be sought by nano-engineering and/or self-assembly of interfaces, integrating several functionalities in single components and/or by developing thinner layers to reduce material consumption and ohmic losses.

The new sustainable-by-design electrolysers will operate at temperature ≤ 600°C to minimise thermally induced degradation and promote efficient thermal management.

Proposals should address the following requirements:

• Design of new cells and/or stacks e.g. metal or electrode supported cells/stacks, cells with integrated interconnect/current collector/electrode and/or metal-based monolith cells/stacks and/or intrinsically more robust cell/stack design/assembly, and validation on single cell and short stack level;
• Dedicated test protocols at cell and/or short stack level will be developed to establish performance and degradation rate of the cell/short stack under variable load profiles. Accelerated stress tests could be applied for shortening the testing time for degradation evaluation. This task will also contribute to evaluate the flexibility of operation of the devices;
• The stack design shall be assisted by fluid dynamics and multi-physics modelling to determine the optimal cell and stack architectures considering the specific electrochemistry and the thermal management within the stack, as well as to define optimal operating conditions of the stack;
• Increased current density of the cells should be obtained by e.g. designing thinner electrolytes and/or new electrodes with improved materials/architectures;
• Increased Faradaic efficiency shall be obtained by implementing materials solutions and/or by optimising operating strategy;
• Corrosion stability of the metal-based components should be validated in relevant operating conditions, in particular for the steam side of the electrolyser, and if needed, improved by development of protective coatings;
• Degradation mechanisms of the stack components should be identified with respect to temperature, steam content and utilisation, and pressure (for pressurised solution);
• The cell and stack manufacturing methods should be based on processes with potential for later upscaling, automation and mass-manufacturing;
• Techno-economic evaluation of the steam electrolyser integrated in given application(s) and considering economy of scale will provide the Levelised Cost of Hydrogen (LCOH) and will be used to provide insights into relevant business models. The CAPEX and OPEX of the novel stack concept will be evaluated;
• Proposals are expected to address sustainability aspects via Life Cycle Assessment (LCA) by reducing the use of critical raw materials compared to state-of-art cells and/or stacks and/or their recycling.

Consortia are expected to build on the expertise from the European research and industrial community to ensure broad impact by addressing several of the aforementioned items.

Proposals should demonstrate how they go beyond the ambition of projects WINNER, GAMER, PROTOSTACK, METPROCELL and DAICHI European projects and be complementary to them.

For activities developing test protocols and procedures for the performance and durability assessment of electrolysers and fuel cell components proposals should foresee a collaboration mechanism with JRC (see section 2.2.4.3 "Collaboration with JRC"), in order to support EU-wide harmonisation. Test activities should adopt the already published EU harmonised testing protocols to benchmark performance and quantify progress at programme level.

For additional elements applicable to all topics please refer to section 2.2.3.2.

Activities are expected to start at TRL 2 and achieve TRL 4 by the end of the project - see General Annex B.

The JU estimates that an EU contribution of maximum EUR 3.00 million would allow these outcomes to be addressed appropriately.

The conditions related to this topic are provided in the chapter 2.2.3.2 of the Clean Hydrogen JU 2024 Annual Work Plan and in the General Annexes to the Horizon Europe Work Programme 2023–2024 which apply mutatis mutandis