From Concept to Prototype: How C-DICE Sandpit funding accelerated the development of Sub-H2 

In early 2024, Dr Lizzie Ashton, Senior Research Associate at Loughborough University received seedcorn funding for a research team through the C-DICE Sandpit programme to investigate the viability of integrating battery-electrolyser technology with solid-state hydrogen storage. This led to the development of Sub-H2 – a system designed to produce, store, and release green hydrogen in a compact, self-contained unit. 

In this blog, Lizzie outlines how the support from C-DICE, UKRI Research England, and HyDEX enabled the team to move this concept from an idea to a functional laboratory prototype, with economic modelling and clear future potential. 

The Sub-H2 project explores the use of battery-electrolysers – hybrid devices capable of acting as both batteries and electrolysers – to generate hydrogen, which can then be stored in advanced solid-state materials. Sub-H2 aims to bridge the gap between the two technologies, offering a flexible solution for decentralised power, off-grid energy storage, and grid balancing applications. 

The £30,000 C-DICE Sandpit seedcorn funding enabled us to carry out feasibility studies and prototype development. This included: 

• Hydrogen purity testing for compatibility with storage materials (99 % purity was achieved)  
• Characterisation of a range of hydrogen storage materials
• Development of a small-scale Sub-H2 prototype
• Economic modelling and performance evaluation

A key part of our research focused on improving how hydrogen can be stored, achiving more hydrogen per weight and volume in comparison to existing methods. We also wanted to ensure the safe release of hydrogen as low temperature and pressure. We tested compounds such as magnesium hydride (MgH₂) and aluminium hydride (AlH₃), embedding them in ultra-thin, layered materials made of carbon and nitrogen (graphitic carbon nitride, or g-C₃N₄). This nanoscale structure changed how the materials behaved, with several promising outcomes: 

• Hydrogen release at lower temperatures: Traditionally, these materials release hydrogen at 300–400°C. With our nanoconfined systems, we observed hydrogen release at around 200°C. This lower temperature reduces energy demand and makes hydrogen release/reabsorption more efficient. 
• Hydrogen reabsorption under milder conditions: While AlH₃ remains challenging to recharge at low pressures, we found that MgH₂ could be rehydrogenated at 250°C and 20 bars of pressure—conditions that are more practical for cycling hydrogen in and out of storage. 
• Improved material stability over time: The nanostructured design helped prevent particle clumping and maintained surface area, which helped the materials perform more consistently across repeated use cycles. 
• Better air and moisture tolerance: Although these hydrides are usually sensitive to air and water, the layered carbon-nitrogen coating delayed their reaction with the environment, improving safety during handling and storage. 

This approach also allows for further optimisation, as these nanostructured hydrides can potentially be combined with catalysts or additives to tailor performance even more precisely. 

Our work builds on the battery-electrolyser development for the LoCEL-H2, MESCH and ZCIC projects, which both focus on sustainable, decentralised energy systems. Sub-H2 investigates how hydrogen produced from battery-electrolyser cells can be effectively stored in solid materials at low pressure. In the long term, we hope the Sub-H2 model will support these larger-scale systems by providing high energy density and safe hydrogen storage options tailored for future deployment. For example, supporting wind farms in the UK to reduce curtailment. 

“The support we received as early career researchers through C-DICE and HyDEX has been a key enabler of progress. The structured workshops, proposal guidance, and mentoring helped us look at our research from multiple perspectives: from technical feasibility to scalability, and from lab-based experimentation to real-world impact.“

We particularly benefited from the guidance of the C-DICE team, whose advice on framing interdisciplinary proposals, defining outputs, and planning pathways to impact helped shape the direction of the project. Their input also helped us think more strategically about how to build momentum toward future funding, instead of the technical focus we were used to. 

C-DICE and HyDEX also provided us with a platform to share our work widely. We presented at several HyDEX events, which helped us build links with stakeholders from the hydrogen and energy storage sectors. These interactions provided valuable feedback and ensured that our work remains aligned with the needs of industry. 

Support from Consortium for Battery Innovation (CBI) members also helped guide modelling assumptions for larger-scale Sub-H2 systems. 

Some of our early results have been published in an IEEE paper on the Economic Viability of a Battery-Electrolyser System for Frequency Response and Hydrogen Production, and we presented internationally at ICRERA 2024 in Nagasaki, Japan. We are now preparing a follow-up publication for submission to ACS Chemistry of Materials, focusing on the performance and integration of the solid-state hydrogen storage materials. 

Looking ahead, we plan to apply for further funding to explore how solid-state storage can support hydrogen generated from larger-scale battery-electrolyser systems. The Sub-H2 prototype has helped us validate core concepts and has laid the groundwork for scalable, practical hydrogen storage solutions that align with net-zero goals. 

“For early career researchers, the C-DICE Sandpit provided a rare opportunity to connect research ideas with real-world challenges – and to turn a technically ambitious idea into a viable project” 

By Dr Lizzie Ashton, Loughborough University

Find out more about the C-DICE Sandpit programme and the battery-electrolyser research conducted at Loughborough University using the links below: