Periodic Reporting for period 2 - MOST-H2 (Novel metal-organic framework adsorbents for efficient storage of hydrogen)
Período documentado: 2023-12-01 hasta 2025-05-31
Widespread use of hydrogen as an energy carrier is a key priority for the EU, in order to achieve its climate and energy transition targets. Hydrogen can be produced from renewable sources and stored as gas (compressed, cH2 or cryo-compressed, CcH2), liquid (LH2 at ~20K), chemically bound to liquid organic carriers, or solids or physically adsorbed onto porous materials. Chemical routes are associated with increased binding energies and require elaborate heat management schemes, while poor cyclability, slow kinetics and high desorption temperatures are important limitations from the application viewpoint. Physical processes like compression and liquefaction, although more advantageous, are energy intensive due to the required multi-stage compression (up e.g. to 700 bar) or cooling (down to ~20K). Moreover, these processes require the use of expensive composite or heavily thermally insulated bulky containers but they are also connected with critical safety considerations as they may involve very high pressures (cH2) or continuous H2 boil-off (LH2). The use of nanoporous (pore dimensions < 100 nm) materials for H2 storage is based on physical adsorption, involving weak physical gas-solid interactions. Gas adsorption is a spontaneous, exothermic, dynamic gas-solid equilibrium process favored at low temperatures and medium pressures (e.g. 77K, 100 bar). Although the search for effective H2 adsorbents has been ongoing for at least two decades, there are still significant challenges in developing and deploying nanoporous materials suitable for H2 storage.
Among the broad range of hydrogen adsorbents that have been investigated to date, metal-organic frameworks (MOFs) that are light-weight, highly ordered, porous crystals formed by combining inorganic building units (metal ions or clusters) and organic linkers, are considered to have notable advantages over other porous solids.
Despite intense research efforts worldwide, the development of actual MOF-based H2 storage systems and processes is an underdeveloped area of research, as there is a clear technological gap on how to identify suitable low-cost MOFs with the optimum combination of volumetric and gravimetric capacity but also negligible environmental footprint, and incorporate them into storage tanks. MOST-H2 directly addresses this challenge by mainly aiming at:
- Designing and developing new MOFs with usable H2 storage capacities of at least 10 wt% and 50 g/L below 100 bar.
- Developing a demonstration cryo-adsorption H2 storage system delivering up to 500 g of H2.
In this context, advanced synthetic strategies and sophisticated computational techniques, including machine learning, are being combined to deliver new, sustainable-by-design MOF adsorbents with suitable properties that can lead to more efficient, intrinsically safer and cost-effective storage solutions, compared to conventional hydrogen storage technologies. An important part of the project is also being devoted to designing, modeling and finally developing a cryo-adsorption storage tank, which will be properly tested in a TRL 5 environment. The project developments are also being coupled with full life cycle analysis and techno-economic assessment of the MOST-H2 technology to assess its potential with a view to selected end uses (rail and road applications).
Among the broad range of hydrogen adsorbents that have been investigated to date, metal-organic frameworks (MOFs) that are light-weight, highly ordered, porous crystals formed by combining inorganic building units (metal ions or clusters) and organic linkers, are considered to have notable advantages over other porous solids.
Despite intense research efforts worldwide, the development of actual MOF-based H2 storage systems and processes is an underdeveloped area of research, as there is a clear technological gap on how to identify suitable low-cost MOFs with the optimum combination of volumetric and gravimetric capacity but also negligible environmental footprint, and incorporate them into storage tanks. MOST-H2 directly addresses this challenge by mainly aiming at:
- Designing and developing new MOFs with usable H2 storage capacities of at least 10 wt% and 50 g/L below 100 bar.
- Developing a demonstration cryo-adsorption H2 storage system delivering up to 500 g of H2.
In this context, advanced synthetic strategies and sophisticated computational techniques, including machine learning, are being combined to deliver new, sustainable-by-design MOF adsorbents with suitable properties that can lead to more efficient, intrinsically safer and cost-effective storage solutions, compared to conventional hydrogen storage technologies. An important part of the project is also being devoted to designing, modeling and finally developing a cryo-adsorption storage tank, which will be properly tested in a TRL 5 environment. The project developments are also being coupled with full life cycle analysis and techno-economic assessment of the MOST-H2 technology to assess its potential with a view to selected end uses (rail and road applications).
The main results achieved in the first 36 months of the project can be highlighted as follows:
- Construction and evaluation of the MOST-H2 database comprising approximately 10,000 (virtual) MOF materials with specific topologies (targeted by the project), surpassing to a large degree the initial aim to create a database of 1,000 materials. Machine Learning (ML) techniques coupled with molecular simulations were employed to predict the hydrogen adsorption properties of such MOF structures, while the ML approaches were further assisted by a novel “MOF synthesizability” prediction tool. The MOST-H2 computational methodology revealed the key structural/pore network characteristics (porosity, pore size, density, etc.) that can optimize the H2 storage performance of MOFs, while specific topologies and liners were proposed.
- Lab-scale development of a good number of novel, highly porous MOFs variances with hierarchical porosity and hydrogen sorption capacities (both gravimetric and volumetric) surpassing the technical targets of the project, demonstrating a strong application potential.
- Investigation of alternative green MOF synthesis routes to facilitate upscaled material production in the form of monoliths.
- Investigation of different approaches for improved thermal management at the monolith level through the development of MOFs/graphite flakes composites but also at the tank scale by designing and modeling passive or active cooling strategies.
- Cradle to grave life cycle assessment of MOF materials relevant for the scope and objectives of the MOST-H2 project.
- Construction and evaluation of the MOST-H2 database comprising approximately 10,000 (virtual) MOF materials with specific topologies (targeted by the project), surpassing to a large degree the initial aim to create a database of 1,000 materials. Machine Learning (ML) techniques coupled with molecular simulations were employed to predict the hydrogen adsorption properties of such MOF structures, while the ML approaches were further assisted by a novel “MOF synthesizability” prediction tool. The MOST-H2 computational methodology revealed the key structural/pore network characteristics (porosity, pore size, density, etc.) that can optimize the H2 storage performance of MOFs, while specific topologies and liners were proposed.
- Lab-scale development of a good number of novel, highly porous MOFs variances with hierarchical porosity and hydrogen sorption capacities (both gravimetric and volumetric) surpassing the technical targets of the project, demonstrating a strong application potential.
- Investigation of alternative green MOF synthesis routes to facilitate upscaled material production in the form of monoliths.
- Investigation of different approaches for improved thermal management at the monolith level through the development of MOFs/graphite flakes composites but also at the tank scale by designing and modeling passive or active cooling strategies.
- Cradle to grave life cycle assessment of MOF materials relevant for the scope and objectives of the MOST-H2 project.
The work so far has already led to important achievements mainly with respect to the material development activities, going well beyond the State of the Art as:
(a) Two novel families of MOF materials have been discovered, offering new concepts in MOF crystal engineering. The versatile nature of the new materials opens the door for developing structures never considered in the past. For this reason a high impact scientific paper has been published while a pertinent patent application has been filed for the first family. The second MOF family revealed record high gravimetric H2 adsorption capacity and a new high impact publication is currently underway.
(b) By following tightly a materials’ selection roadmap, the MOST-H2 consortium has already determined the optimum MOF structure that will be used in the demonstrator tank. The material can indeed be produced in monolithic form through a scalable green chemistry route.
(c) The tank design has been concluded and the tank construction will take place in the second semester of 2025.
(a) Two novel families of MOF materials have been discovered, offering new concepts in MOF crystal engineering. The versatile nature of the new materials opens the door for developing structures never considered in the past. For this reason a high impact scientific paper has been published while a pertinent patent application has been filed for the first family. The second MOF family revealed record high gravimetric H2 adsorption capacity and a new high impact publication is currently underway.
(b) By following tightly a materials’ selection roadmap, the MOST-H2 consortium has already determined the optimum MOF structure that will be used in the demonstrator tank. The material can indeed be produced in monolithic form through a scalable green chemistry route.
(c) The tank design has been concluded and the tank construction will take place in the second semester of 2025.