CFPs: Improved Lifetime and Cost of High-Temperature Electrolysers Project

Scope

• The scope of this topic is centred around minimising the effects of degradation to consequently extend the lifetime of high temperature steam electrolysers (HTSE) such as solid oxide electrolysers (SOEL) and proton-conducting ceramic electrolysers (PCCEL). HTSE technology has the potential to achieve a low cost of hydrogen production because of its higher energy efficiency due to the operation at high temperature.
• However, because of the latter, degradation mechanisms such as electrocatalyst agglomeration and migration, delamination of electrodes from electrolyte layers, interconnects oxidation, thermal cycling failure and structure cracking for instance of sealings are common sources of lifetime degradation and further reasons for the replacement of components or even full stacks. In addition to that, instability in load due to renewables intermittency or grid fluctuations are also sources of degradation and need to be addressed accordingly.
• Moreover, the link between materials improvements and design (of cells, stacks, modules, systems, and balance of plant) should be demonstrated. Electrolysers are supposed to target lifetimes of over 40,000 hours, albeit undergoing long-term calendar tests (> 10,000 hours) is rather impractical, and thereby this sets the scene for accelerated-stress tests (AS-T) and modelling techniques that can predict the lifetime achieved by potential new technologies.
• Considering the above-given background, the project should address the following issues:
  • Materials and advanced manufacturing techniques improvements aiming to address the deactivation of electrocatalysts within the fuel electrode, microstructure sintering and interdiffusion between species within the oxygen electrode, degradation of sealing due to long-term high temperature operation, chromium oxidation in interconnect stainless steels and growth of poorly conducting oxide layers between the metallic interconnect plates and the electrodes;
  • Development of circularity by working on upstream and downstream recycling processes, targeting to minimise the utilisation of raw critical materials. In particular, design strategies that allow for facile re-utilisation of half-cell materials, utilisation of manufacturing scrap in the process, as well as the development of materials originating from downstream recycling within the stack;
  • Optimisation of load variation and fluctuation including the electrolysers’ integration with renewable energy sources;
  • Optimisation of BoP components and architectures to minimise their impact on stack degradation and improve overall system performances (e.g. steam generator, power quality from the power electronics components towards the electrolyser plant under Renewable Energy conditions, valorisation of stack heat for hydrogen compression, optimisation of gas purification concept, efficient multi-stack design etc.);
  • Introduction of techniques to understand long-term degradation, such as accelerated-stress tests, and modelling.

Objectives

• Project results are expected to contribute to the following objectives and 2030 KPIs of the Clean Hydrogen JU SRIA for SOEL and PCCEL, as follows:
  • SOEL:
    • To reach current densities over 1.2 A/cm2 at thermoneutral voltage;
    • To demonstrate average degradation rates lower than 0.5%/1,000 h or equivalent to 6.4 mV/1,000 h per cell, on thermoneutral voltage;
    • To operate steadily with an electrical demand of < 37 kWh/kg of H2 and a heat demand of < 8 kWh/kg of H2 at nominal capacity at a system level.
  • PCCEL:
    • To reach current densities over 1.0 A/cm2 at thermoneutral voltage;
    • To demonstrate average degradation[1] rates lower than 0.8%/1,000 h or equivalent to 10.3 mV/1,000 h per cell, on thermoneutral voltage;
    • To operate steadily with an electrical demand of < 40 kWh/kg of H2 and a heat demand of < 10 kWh/kg of H2 at nominal capacity at a system level.

Expected Outcomes

• Project results are expected to contribute to the following expected outcomes:
  • Improvements to already conceptualised novel materials including electrocatalysts, electrodes, metallic interconnects, coatings, and seals enabling increased lifetime to the ensemble of both single cells and stacks;
  • Use of advanced manufacturing techniques to tackle issues with interfaces within the cell structure to minimise polarisation;
  • Promote circularity of materials and components, by working on upstream (during manufacturing) and downstream (end of life) recycling, to integrate recycled materials, such as Ni, Co, Ce, La, and others, into the components, addressing the concerns with critical raw materials utilisation and hence strengthening the European hydrogen value chain on high-temperature electrolysers;
  • Improvements to eventual multi-stack configuration to minimise the degradation mechanisms through optimising the control of the different stacks and the interactions between them, as well as BoP architecture;
  • Introduction of accelerated stress test protocols on both single cell and stack levels to assure quality and lifetime of cells, stacks, and ultimately systems, including BoP;
  • Balance of plant configuration that demonstrates satisfying performances at the system level. This includes new stack insulation strategies and materials, hot box systems, improved power electronics, innovative valorisation strategy of waste heat (e.g., for efficient compression or gas purification), and innovative design for multi-stack configuration. This innovative balance of plant configuration will enable to optimise the efficiency of the system’s lifetime and reliability;
  • Paving the way towards European leadership for renewable hydrogen production from high-temperature electrolysis, with enhanced heat integration.

Eligibility Criteria

• Any legal entity, regardless of its place of establishment, including legal entities from non associated third countries or international organisations (including international European research organisations) is eligible to participate (whether it is eligible for funding or not), provided that the conditions laid down in the Horizon Europe Regulation have been met, along with any other conditions laid down in the specific call/topic.
• A ‘legal entity’ means any natural or legal person created and recognised as such under national law, EU law or international law, which has legal personality and which may, acting in its own name, exercise rights and be subject to obligations, or an entity without legal personality.
• To be eligible for funding, applicants must be established in one of the following countries:
  • the Member States of the European Union, including their outermost regions
  • the Overseas Countries and Territories (OCTs) linked to the Member States
  • countries associated to Horizon Europe.

For more information, visit EC.