HT proton conducting ceramic materials for highly efficient and flexible operation

Based on the challenge of PCC based technologies for efficient green hydrogen processing and handling both in terms of materials, performance, cell and reactor, this topic calls for an integrated approach of material science, reactor design and multiscale modelling. It is expected to reach a significant performance enhancement on materials (increased current density and mechanical integrity, reduced over-potentials), and at the elaboration of a proof of concept reactor design taking into account the physical, mechanical and chemical properties of materials.

Most national and EU projects have focused so far on the development of PCCs for use as fuel cells or electrolysers. Planar cell-based technologies have been investigated in EFFIPRO [66] and METPROCELL [67] projects and tubular cell-based technologies devoted to high-pressure electrolysis in the FCH 2 JU ELECTRA and GAMER projects [68], the latter focusing on 10 kW prototype demonstrations.

The main objective of the topic is to go beyond the above state-of-the-art, arriving to a laboratory scale validation and a PCC technology system operated in different conditions. Among the different testing conditions, mechanical stability, electric conductivity and high proton throughput should be tested in different operation modes.

The project should therefore cover the following aspects:

• Qualification of novel materials (electrodes, electrolyte, robust mechanical substrates, sealants, current collectors and interconnects) suitable for stable operation under pressure and purity gradients;
• Development of cell or reactor components and included in at least two architectures (e.g. robust composite and/or graded electrodes with high electro-catalytic activities, thin film electrolyte with high crystallinity). The applied manufacturing processes should be industrially scalable;
• Multi-scale modelling from the meso-scale up to the single unit level, to enhance the performance of specific materials and to support the development of manufacturing processes towards improved stack / reactor design. The model should be validated by relevant experimental data;
• The proposed materials and cells should be implemented in short stacks and/or mini-reactors (with at least 5 repeating units scaled at industrially-relevant size; i.e. 80-100 cm2 per repeat unit). The short stacks and mini reactors should be tested in a configuration allowing pumping of hydrogen, monitoring the hydrogen production, purity and pressure levels;
• Insight on the correlation of performance and degradation mechanisms should be gained, including on/off cycles and dynamic operation. This should be the base for designing various PCC electrochemical reactors, enabling process intensification (e.g. shifting chemical equilibria) and electro-synthesis reactors to increase efficiency of overall chemicals and/or green fuel production with low or no CO2 footprint;
• A comprehensive assessment of the environmental impact through life cycle assessment, comparing the proposed solution with conventional purification and compression technologies, should be also performed. This should provide a full techno-economical comparison;
• As an option, the reversible operation between electrolysis and fuel cell modes in a PCC cell should be considered too;
• As another option, the design and validation of a short stack and/or mini reactor in green fuels synthesis (e.g. CO2 reduction, direct electro-synthesis of hydrocarbons) might be included.

The project should bring together the research on proton ceramic conducting materials with the further exploitation of materials of interest for the industry in the next scaling up of the technology.

The consortium should therefore include both academia and industry and should ideally leverage international collaborations. The project should build on existing know-how on cells and stack manufacturing and synergies to other electroceramic processes should be sought.

TRL at start: 2 and TRL at the end of the project: 4

Any safety-related event that may occur during execution of the project shall be reported to the European Commission's Joint Research Centre (JRC) dedicated mailbox JRC-PTT-H2SAFETY@ec.europa.eu which manages the European hydrogen safety reference database, HIAD and the Hydrogen Event and Lessons LEarNed database, HELLEN.

The project should contribute towards the activities of Mission Innovation - Hydrogen Innovation Challenge. Cooperation with entities from Hydrogen Innovation Challenge member countries, which are neither EU Member States nor Horizon 2020 Associated countries, is encouraged (see chapter 3.3 for the list of countries eligible for funding, and point G. International Cooperation).

The FCH 2 JU considers that proposals requesting a contribution from the EU of EUR 3 million would allow this specific challenge to be addressed appropriately. Nonetheless, this does not preclude submission and selection of proposals requesting other amounts.

Expected duration: 3 years

[66] https://cordis.europa.eu/project/rcn/89271/brief/en

[67] https://cordis.europa.eu/project/rcn/101146/factsheet/en

[68] https://www.fch.europa.eu/page/fch-ju-projects

Green hydrogen is crucial to meet the CO2 reduction objectives of the industry (e.g. e-chemicals etc.) and in the transportation sector (e.g. fuel cell cars, e-fuels). In this context, the demand of high-quality hydrogen regarding dryness, purity and pressure is steadily increasing. Although conventional methods like mechanical compressors, zeolites, and thermal drying cycles to clean, dry and compress hydrogen are economic and reliable at large scales, they have not been optimised to the scale of decentralised hydrogen production such as electrolysis. Commonly several conventional processing steps are simply put in series in a non-integrated way, resulting in high equipment and maintenance costs, significant energy and limited reliability.

Electrochemical hydrogen pumping for drying, purification and compression presents a radically different approach to fulfil the high-quality requirements of fuel cell applications in various fields, including mobility, Power-to-X and to Power-to-Power. The most advanced technology in this field is based on symmetric high temperature Polymer Electrolyte Membrane, however only marginal progress has been achieved over the last decade and the commercial maturity is yet to be reached.

Proton conducting Ceramic Cells (PCC) represent a promising alternative way to compress and purify hydrogen. They can extract hydrogen from low pressure levels, low concentrations or mixed with pollutants like CO in a single step to more practical pressure levels and adequate levels of purity. PCCs operate in a temperature range of 400°C – 700°C and allow seamless heat integration options. The use of noble metals is avoided, as these cells are based on inexpensive and abundantly available materials. Therefore, the technology is extremely attractive for an efficient thermal integration when coupled with other chemical processes (e.g. steam biogas reforming, methanation etc.). In combination with reversible Solid Oxide Cells, they open the door to exceed 50% round-trip efficiency for power-to-power applications that can offer a significant contribution to seasonal energy storage. PCCs are however at an early stage of development. The current challenge is to overcome the limited understanding at the materials level and the lack of optimized stack / reactor designs for energetically integrated downstream processing of hydrogen.

The project results are expected to unlock a path towards commercially viable technology based on PCC technology for dry, pure and pressurized hydrogen extraction from various gaseous streams (any type of electrolysers, biological processes, gasification processes) at a small to medium scale. Single step delivery of pressurized hydrogen will allow efficient integration in the process chain to reduce the overall cost for using hydrogen as energy vector. This will enable the EU players to take a strategic worldwide lead position in PCC technologies.

Insight on the correlation of performance and degradation mechanisms should be gained, including on/off cycles and dynamic operation. This will be the base for designing various PCC electrochemical reactors, enabling process intensification (shifting chemical equilibria) and electro-synthesis reactors to increase efficiency of overall chemicals and/or green fuel production with low or no CO2 footprint.

To leverage the impact of the proposed solutions, following KPIs should therefore reached:

• ASR of cells/stacks: < 1 ohmcm2 at 650°C, Faradaic efficiency > 95 %;
• Validation of the durability of cells for at least 3,000 hours and validation of short stacks/mini reactors in selected applications for at least 1,000 hours of operation;
• Processing of hydrogen with a production loss rate of less than 1.2 %/1,000 hours;
• Cell and stack architectures allowing for a pressure ratio across a single membrane (H2 partial pressure increase) of at least 5 and/or cell and stack design extracting hydrogen from concentrations as low as 10 hPa (e.g. 1% H2 admixture in CH4), to offer an economic option for H2 distribution in the existing natural gas infrastructure (reverse step of H2 admixing).

The conditions related to this topic are provided in the chapter 3.3 of the FCH2 JU 2020 Annual Work Plan and in the General Annexes to the Horizon 2020 Work Programme 2018– 2020 which apply mutatis mutandis.