Periodic Reporting for period 3 - EPISTORE (Thin Film Reversible Solid Oxide Cells for Ultracompact Electrical Energy Storage)
Okres sprawozdawczy: 2023-07-01 do 2025-06-30
In the last decades, advanced thin film technology has enabled a wide range of technological breakthroughs that have transformed entire sectors such as electronics and lighting by the implementation of outstanding nanoscale phenomena in reliable products that involve ultralow contents of critical raw materials (CRMs). Epistore aims to revolutionize the energy storage sector by developing pocket-sized kW-range stacks based on thin film reversible Solid Oxide Cells (TF-rSOCs) that will be able to efficiently store renewable electricity for applications where the use of batteries is inefficient due to size constraints or long term storage requirements, e.g. off-shore power generation or transportation. Nanoscale breakthroughs and never explored materials will be combined in revolutionary TF-rSOCs giving rise to radically new ultracompact and fast response Power-to-Gas and Power-to-Power storage solutions with superior performance (hydrogen production of 10kg/l per hour and specific power of 2.5kW/kg) and negligible use of CRMs (50mg/kW). In order to enable this science-to-technology step forward, our nano-enabled TF-rSOCs will be integrated in scalable silicon technology to show their viability as a potentially low-cost new paradigm of large-scale energy storage.
The project achieved major progress in developing next-generation thin-film reversible solid oxide cell (TF-rSOC) technologies, from nanoscale materials to complete system integration.
WP2 – Advanced Tools for Solid-State Nanoionics
New analytical and modelling tools were created to understand and optimize nanoscale processes in solid oxide cells. Atom probe tomography combined with isotopic exchange provided unique insights into grain boundary chemistry, while near-ambient pressure XPS and NEXAFS revealed electronic and bonding structures. A major breakthrough was the development of Isotopic Exchange Raman Spectroscopy (IERS) to measure ion diffusion and surface exchange. The method was expanded to a wide range of materials, including Raman-inactive ones, and patented as a standardized tool for in situ ion transport studies. Combinatorial thin-film screening, rapid composition analysis using GDOES, and a 3D FEM model for oxygen electrodes further advanced understanding of transport and reaction mechanisms.
WP3 – Nanoscale Enhanced and Stable Thin-Film Electrolytes
Dense and homogeneous YSZ thin films were fabricated with ionic conductivities surpassing literature benchmarks. High-entropy oxide electrolytes showed excellent conductivity at intermediate temperatures, offering alternatives to YSZ. Protective CeO2- and ZrO2-based coatings were produced using low-temperature processes, achieving high purity and crystallinity. Thin barrier layers were successfully implemented on large-area cells, improving overall performance and durability.
WP4 – Nanoscale Engineered High-Performance Thin-Film Electrodes
Novel nanocomposite and vertically aligned electrode architectures achieved record-low area-specific resistance and strong performance at moderate temperatures. These electrodes showed excellent reversibility in both fuel cell and electrolysis modes, with current densities up to 25% higher than planar films. High-entropy oxide and exsolved materials were integrated into compatible stack structures, marking a key step toward industrial application. Doped aluminates produced active nanoparticles at low temperature, confirming their efficiency as electrocatalysts and enabling a new generation of high-performance electrodes.
WP5 – Micro and Nano Technologies for Thin-Film rSOC Cells
Large-area thin films (up to 10 cm) were fabricated and transferred onto silicon, ceramic, and metallic substrates. Alternative fabrication routes to the complex Silicon-on-Nothing concept were successfully developed, producing transferable functional structures. Extensive work was done on single repeating units, including deposition of electrodes, electrolytes, and barrier layers using DLI-CVD, PI-MOCVD, and AP-SALD. New test setups, interconnects, and sealing systems were implemented, enabling reliable assembly and testing of full thin-film cells.
WP6 – TF-rSOC Stacks and P2G/P2P Energy Storage
A “rainbow stack” of anode-supported cells with thin-film oxygen electrodes was fabricated and tested for 1,000 hours in both SOFC and SOEC modes, showing stable operation and enabling a 95% reduction in electrode material use. 3D-printed electrolyte-supported cells with thin-film electrodes achieved high performance while minimizing material demand. Metal interconnectors, glass-ceramic sealing, and SLA-printed encapsulations were successfully demonstrated, leading to robust and fully integrated stack configurations.
WP2 – Advanced Tools for Solid-State Nanoionics
New analytical and modelling tools were created to understand and optimize nanoscale processes in solid oxide cells. Atom probe tomography combined with isotopic exchange provided unique insights into grain boundary chemistry, while near-ambient pressure XPS and NEXAFS revealed electronic and bonding structures. A major breakthrough was the development of Isotopic Exchange Raman Spectroscopy (IERS) to measure ion diffusion and surface exchange. The method was expanded to a wide range of materials, including Raman-inactive ones, and patented as a standardized tool for in situ ion transport studies. Combinatorial thin-film screening, rapid composition analysis using GDOES, and a 3D FEM model for oxygen electrodes further advanced understanding of transport and reaction mechanisms.
WP3 – Nanoscale Enhanced and Stable Thin-Film Electrolytes
Dense and homogeneous YSZ thin films were fabricated with ionic conductivities surpassing literature benchmarks. High-entropy oxide electrolytes showed excellent conductivity at intermediate temperatures, offering alternatives to YSZ. Protective CeO2- and ZrO2-based coatings were produced using low-temperature processes, achieving high purity and crystallinity. Thin barrier layers were successfully implemented on large-area cells, improving overall performance and durability.
WP4 – Nanoscale Engineered High-Performance Thin-Film Electrodes
Novel nanocomposite and vertically aligned electrode architectures achieved record-low area-specific resistance and strong performance at moderate temperatures. These electrodes showed excellent reversibility in both fuel cell and electrolysis modes, with current densities up to 25% higher than planar films. High-entropy oxide and exsolved materials were integrated into compatible stack structures, marking a key step toward industrial application. Doped aluminates produced active nanoparticles at low temperature, confirming their efficiency as electrocatalysts and enabling a new generation of high-performance electrodes.
WP5 – Micro and Nano Technologies for Thin-Film rSOC Cells
Large-area thin films (up to 10 cm) were fabricated and transferred onto silicon, ceramic, and metallic substrates. Alternative fabrication routes to the complex Silicon-on-Nothing concept were successfully developed, producing transferable functional structures. Extensive work was done on single repeating units, including deposition of electrodes, electrolytes, and barrier layers using DLI-CVD, PI-MOCVD, and AP-SALD. New test setups, interconnects, and sealing systems were implemented, enabling reliable assembly and testing of full thin-film cells.
WP6 – TF-rSOC Stacks and P2G/P2P Energy Storage
A “rainbow stack” of anode-supported cells with thin-film oxygen electrodes was fabricated and tested for 1,000 hours in both SOFC and SOEC modes, showing stable operation and enabling a 95% reduction in electrode material use. 3D-printed electrolyte-supported cells with thin-film electrodes achieved high performance while minimizing material demand. Metal interconnectors, glass-ceramic sealing, and SLA-printed encapsulations were successfully demonstrated, leading to robust and fully integrated stack configurations.
The EPISTORE project established a new science-based technology for zero-emission, compact energy storage, combining nanoscale engineering with advanced materials. It introduced thin-film reversible solid oxide cells (TF-rSOCs) and miniaturized stack systems capable of storing electricity as gas (P2G) or delivering standalone power (P2P).
The project achieved major breakthroughs in TF-rSOC performance, scalability, and material efficiency. Dense, homogeneous YSZ thin films with exceptional ionic conductivity were developed, surpassing conventional electrolytes. High-entropy oxides emerged as promising alternatives with high conductivity at intermediate temperatures, and thin barrier layers were implemented on large-area cells to enhance durability.
In electrode development, innovative nanocomposite and vertically aligned structures achieved record-low resistance and high efficiency in both fuel cell and electrolysis modes. High-entropy and exsolved materials were integrated into commercial-type cells, and production of these complex materials was successfully scaled using spray pyrolysis. Doped aluminate electrodes showed excellent catalytic activity through nanoparticle exsolution, confirming their strong potential for energy conversion applications.
At the cell and stack level, large-area thin-film cells (up to 10 cm) were fabricated and transferred onto silicon, ceramic, and metal substrates. A TF-rSOC rainbow stack was tested for 1,000 hours in both SOFC and SOEC modes, showing stable operation with a 95% reduction in electrode material use. 3D-printed stack configurations, optimized sealing, and interconnect solutions ensured robust integration and operation.
The project delivered a new generation of efficient, low-temperature solid oxide devices that combine high performance with minimal resource use. These advances reduce costs, improve energy efficiency, and strengthen Europe’s leadership in clean, sustainable energy technologies. Over 50 scientific publications have expanded knowledge of nanoscale processes and materials, supporting the transition to a decarbonized energy system.
The project achieved major breakthroughs in TF-rSOC performance, scalability, and material efficiency. Dense, homogeneous YSZ thin films with exceptional ionic conductivity were developed, surpassing conventional electrolytes. High-entropy oxides emerged as promising alternatives with high conductivity at intermediate temperatures, and thin barrier layers were implemented on large-area cells to enhance durability.
In electrode development, innovative nanocomposite and vertically aligned structures achieved record-low resistance and high efficiency in both fuel cell and electrolysis modes. High-entropy and exsolved materials were integrated into commercial-type cells, and production of these complex materials was successfully scaled using spray pyrolysis. Doped aluminate electrodes showed excellent catalytic activity through nanoparticle exsolution, confirming their strong potential for energy conversion applications.
At the cell and stack level, large-area thin-film cells (up to 10 cm) were fabricated and transferred onto silicon, ceramic, and metal substrates. A TF-rSOC rainbow stack was tested for 1,000 hours in both SOFC and SOEC modes, showing stable operation with a 95% reduction in electrode material use. 3D-printed stack configurations, optimized sealing, and interconnect solutions ensured robust integration and operation.
The project delivered a new generation of efficient, low-temperature solid oxide devices that combine high performance with minimal resource use. These advances reduce costs, improve energy efficiency, and strengthen Europe’s leadership in clean, sustainable energy technologies. Over 50 scientific publications have expanded knowledge of nanoscale processes and materials, supporting the transition to a decarbonized energy system.