Periodic Reporting for period 1 - X-SEED (eXperimental Supercritical ElEctrolyser Development)
Reporting period: 2024-01-01 to 2025-06-30
Climate change has significant impacts on the environment, health, and economy. It is imperative to reduce energy consumption, increase efficiency, and decarbonize economy. Increasing energetic efficiency is no longer sufficient - a radical paradigm shift is needed, starting with energetic carriers. Hydrogen (H2) is expected to play a key role: It is essential for ensuring the energy security of the European Union (EU) and becoming the world’s first climate-neutral continent by 2050. The REPowerEU plan aims at producing 10 million tons of green H2 in the EU. Green H2 is obtained mainly by electrolysis (the decomposition of water molecules into oxygen (O2 and H2). There are several types of electrolysers: alkaline (AWEL), proton exchange membrane (PEMEL), solid oxide (SOEL), anion exchange membrane (AEMEL). AWEL and PEMEL are already commercial but have three main bottlenecks: high production costs (5-8 €/kg H2), limited efficiencies (> 50 kWh/kg H2) and limited industrial manufacturing capacity. Moreover, critical raw materials and other materials with sustainability or environmental concerns are used. To overcome these challenges, it is important to develop and invest in technologies that are expected to have competitive production cost (2-3 €/kg H2), increased efficiency (< 48 kWh/kg H2), improved durability.
X-SEED aims at developing an innovative alkaline membrane-less electrolyser working at supercritical water conditions (>374°C; >220 bar), generating high-quality H2 at pressures over 200 bar. This technology maximizes energetic efficiency, improves circularity, and enhances lifetime, resulting in a more competitive green H2 production. In X-SEED; novel catalysts and electrodes are designed, synthesized, and characterized to ensure high efficiencies. Results are validated at laboratory scale (TRL4) for a single cell and a 5-cell stack. Modeling and cell design ensure laminar fluid flows, allowing H2 and O2 separation employing a membrane-less electrolyser. Supercritical conditions and the membrane-less configuration reduce the electrochemical work required to generate H2 (decreased interface resistances ) and increase system lifetime. This results in an improved energy efficiency (42 kWh/kg H2, > 3 A/cm2), H2 production rate and robustness (degradation rate < 1%/1000h). X-SEED also integrates circularity and sustainability assessments in decision-making, limiting the use of critical raw materials (below 0.3 mg/W) and using wastewater for both catalyst production and electrolyte. The X-SEED consortium possesses extensive technical knowledge and experience in these key technologies. It will realize multiphysics models of cell and stack (DTU, SNAM, IDN, PMat), manufacture and select the best catalyst and electrodes (LEITAT, PMAT, IDN), and design the cell, the stack, and the test bench to validate the supercritical electrolyser at a laboratory scale (IDN, PMat, SNAM). The X-SEED project adds value beyond the technological dimension: It will accelerate the H2 ecosystem, support Europe in meeting climate targets and maintain its leadership position as a technological developer and producer of green energy.
X-SEED aims at developing an innovative alkaline membrane-less electrolyser working at supercritical water conditions (>374°C; >220 bar), generating high-quality H2 at pressures over 200 bar. This technology maximizes energetic efficiency, improves circularity, and enhances lifetime, resulting in a more competitive green H2 production. In X-SEED; novel catalysts and electrodes are designed, synthesized, and characterized to ensure high efficiencies. Results are validated at laboratory scale (TRL4) for a single cell and a 5-cell stack. Modeling and cell design ensure laminar fluid flows, allowing H2 and O2 separation employing a membrane-less electrolyser. Supercritical conditions and the membrane-less configuration reduce the electrochemical work required to generate H2 (decreased interface resistances ) and increase system lifetime. This results in an improved energy efficiency (42 kWh/kg H2, > 3 A/cm2), H2 production rate and robustness (degradation rate < 1%/1000h). X-SEED also integrates circularity and sustainability assessments in decision-making, limiting the use of critical raw materials (below 0.3 mg/W) and using wastewater for both catalyst production and electrolyte. The X-SEED consortium possesses extensive technical knowledge and experience in these key technologies. It will realize multiphysics models of cell and stack (DTU, SNAM, IDN, PMat), manufacture and select the best catalyst and electrodes (LEITAT, PMAT, IDN), and design the cell, the stack, and the test bench to validate the supercritical electrolyser at a laboratory scale (IDN, PMat, SNAM). The X-SEED project adds value beyond the technological dimension: It will accelerate the H2 ecosystem, support Europe in meeting climate targets and maintain its leadership position as a technological developer and producer of green energy.
In 2024, X-SEED’s activities were concentrated on designing an optimized membrane-less electrolyser configuration and developing and characterizing catalyst and electrodes.
Initial efforts were focused on defining parameters and selecting components for the electrolyser operation at supercritical conditions. Two alternative cell designs were being developed and optimized using 2D computational fluid dynamics (CFD) models. Multiphysics models are being designed to predict cell behavior under different conditions (pressure, temperature, electrolyte molarity, etc.). The results indicate proper performance of the membrane-less configuration, achieving oxygen and hydrogen outflows at high quality and out of flammability range.
Perovskites and metal oxides-based catalysts were developed and characterized. Electrochemical performance was evaluated.
The selection of suitable electrode substrate materials was completed, selecting nickel alloy expanded mesh. By identifying an appropriate surface treatment the improvement of the catalyst attachment on the substrate was achieved. The first coated electrode samples were manufactured and characterized.
Furthermore, the X-SEED project started to design the test rig dedicated to single-cell evaluation.
A comprehensive review of the state of the art in relevant patents, with particular emphasis on cell design, materials used for electrodes and catalysts, and processes similar to the X-SEED project were performed. The differences in operational contexts, core technologies, and application objectives ensure that there is no conflict between the intellectual properties described in the patents and those being developed in X-SEED.
Initial efforts were focused on defining parameters and selecting components for the electrolyser operation at supercritical conditions. Two alternative cell designs were being developed and optimized using 2D computational fluid dynamics (CFD) models. Multiphysics models are being designed to predict cell behavior under different conditions (pressure, temperature, electrolyte molarity, etc.). The results indicate proper performance of the membrane-less configuration, achieving oxygen and hydrogen outflows at high quality and out of flammability range.
Perovskites and metal oxides-based catalysts were developed and characterized. Electrochemical performance was evaluated.
The selection of suitable electrode substrate materials was completed, selecting nickel alloy expanded mesh. By identifying an appropriate surface treatment the improvement of the catalyst attachment on the substrate was achieved. The first coated electrode samples were manufactured and characterized.
Furthermore, the X-SEED project started to design the test rig dedicated to single-cell evaluation.
A comprehensive review of the state of the art in relevant patents, with particular emphasis on cell design, materials used for electrodes and catalysts, and processes similar to the X-SEED project were performed. The differences in operational contexts, core technologies, and application objectives ensure that there is no conflict between the intellectual properties described in the patents and those being developed in X-SEED.
Result (R): Design of membrane-less electrolyser – Potential impacts (PI): New electrolyser with high efficiency (< 42 kWh/kgH2) and competitive production cost (2-3 €/kgH2), increase of industrial manufacturability – Key needs (KN): Validate cell and stack level models, scale up of system, IPR protection of design
R: 2D and 3D multiphysics models of electrolysis at supercritical conditions – PI: Parameter improvement of electrolysis at supercritical conditions, optimization of processes with models and data generated – KN: Experimental validation of the models generated, IPR protection
R: Conductivity of different electrolytes (water, KOH, etc.) at supercritical conditions – PI: Optimize the electrolyte formulation and other processes that use water at supercritical conditions – KN: Obtain data of different types of electrolytes, IPR protection, commercialization strategy definition
R: HER and OER catalyst produced by electrospinning – PI: High performance catalyst for electrochemical technologies at ambient/high temperatures, catalyst with lower content of CRM – KN: Further research to demonstrate efficiency and stability of catalysts and to develop the industrial viability of catalyst production, access to funds for industrialization and access to the markets
Result: HER and OER catalyst produced by continuous-hydrothermal flow synthesis (CHFS) – PI: High performance catalyst for electrochemical technologies at ambient/high temperatures, catalyst with lower content of CRM – KN: Further research to demonstrate efficiency and stability of catalysts and to develop the industrial viability of catalyst production, access to funds for industrialization and access to the markets
R: Catalyst produced by CHFS using metals in wastewaters – PI: Industrial wastewater treatment and metal recovery, achieving catalyst for electrolysis applications – KN: Validation of the cost-competitiveness of the process and the quality and performance of obtained catalysts, IPR protection and market access, symbiosis with metal-rich wastewater industry
R: HER and OER electrodes with reduced content of CRM – PI: More sustainable electrodes which reduce the cost of these components and enable cost competitive H2 production, identifying more types of electrodes for electrochemical technologies, enabling the increase of the industrial electrodes manufacturing – KN: Further research to validate the performance and stability of novel electrodes, IPR protection, Access to funds to scale up the manufacture process
R: 2D and 3D multiphysics models of electrolysis at supercritical conditions – PI: Parameter improvement of electrolysis at supercritical conditions, optimization of processes with models and data generated – KN: Experimental validation of the models generated, IPR protection
R: Conductivity of different electrolytes (water, KOH, etc.) at supercritical conditions – PI: Optimize the electrolyte formulation and other processes that use water at supercritical conditions – KN: Obtain data of different types of electrolytes, IPR protection, commercialization strategy definition
R: HER and OER catalyst produced by electrospinning – PI: High performance catalyst for electrochemical technologies at ambient/high temperatures, catalyst with lower content of CRM – KN: Further research to demonstrate efficiency and stability of catalysts and to develop the industrial viability of catalyst production, access to funds for industrialization and access to the markets
Result: HER and OER catalyst produced by continuous-hydrothermal flow synthesis (CHFS) – PI: High performance catalyst for electrochemical technologies at ambient/high temperatures, catalyst with lower content of CRM – KN: Further research to demonstrate efficiency and stability of catalysts and to develop the industrial viability of catalyst production, access to funds for industrialization and access to the markets
R: Catalyst produced by CHFS using metals in wastewaters – PI: Industrial wastewater treatment and metal recovery, achieving catalyst for electrolysis applications – KN: Validation of the cost-competitiveness of the process and the quality and performance of obtained catalysts, IPR protection and market access, symbiosis with metal-rich wastewater industry
R: HER and OER electrodes with reduced content of CRM – PI: More sustainable electrodes which reduce the cost of these components and enable cost competitive H2 production, identifying more types of electrodes for electrochemical technologies, enabling the increase of the industrial electrodes manufacturing – KN: Further research to validate the performance and stability of novel electrodes, IPR protection, Access to funds to scale up the manufacture process