Image credit: Gerd Altmann on Pixabay.
Storing hydrogen safely and efficiently remains one of the biggest challenges to building a hydrogen-powered energy system. Now, researchers have developed a hybrid material that combines two different hydrogen storage mechanisms in a single nanocomposite, enabling hydrogen to be stored and released over a much wider temperature range than conventional magnesium-based storage materials.
The international team led by Dr Yinghui Li at Shanghai Jiao Tong University, and including researchers from the Cambridge Graphene Centre (CGC), designed a nitrogen-doped porous carbon scaffold that not only supports magnesium hydride nanoparticles but also stores hydrogen itself. This dual role overcomes a longstanding drawback of many nanoconfined hydrogen storage systems, where the supporting material adds weight without contributing to hydrogen storage.
The work was published in Nano-Micro Letters.
Two storage mechanisms working together
Hydrogen can be stored in several ways, each with its own advantages and limitations. Porous carbon materials can physically adsorb hydrogen quickly, but only in relatively small quantities and typically at very low temperatures. Magnesium hydride, by contrast, stores much larger amounts of hydrogen through chemical bonding, but usually requires temperatures approaching 300 °C before that hydrogen can be released.
The new material combines these complementary approaches within a single structure. The porous carbon scaffold adsorbs hydrogen at low temperatures, while magnesium hydride nanoparticles confined within its pores provide high-capacity chemical storage. As the material warms, hydrogen is released in two stages: physically adsorbed hydrogen is released first, followed by hydrogen from the magnesium hydride, providing a continuous supply over a broad temperature range.
The researchers also found that confining the magnesium hydride nanoparticles within the porous carbon significantly improved their performance. Hydrogen release began at 175 °C, which is more than 120 °C lower than for conventional magnesium hydride, and the material exhibited faster hydrogen absorption and release, together with excellent stability over repeated charging and discharging cycles.
Designing more practical hydrogen storage materials
Raman spectroscopy was used to characterise the nitrogen-doped carbon scaffold, helping the team understand how its structure supports hydrogen adsorption and interacts with the magnesium nanoparticles. These insights complemented structural and chemical analyses used to optimise the composite material.
The study also showed that the composite can be compressed into dense pellets while maintaining a high volumetric hydrogen storage density, an important consideration for practical energy storage systems. By combining physical adsorption with chemical storage in a single material, the work offers a promising strategy for designing next-generation solid-state hydrogen storage technologies that operate more efficiently across a wider range of temperatures.
As researchers continue working towards hydrogen storage materials capable of operating closer to ambient conditions, the team believes that further optimisation of the porous scaffold could improve performance even further, helping solid-state hydrogen storage move closer to the requirements of future clean energy applications.
Reference: Achieving Wide-Temperature-Range Physical and Chemical Hydrogen Sorption in a Structural Optimized Mg/N-Doped Porous Carbon Nanocomposite Y. Li, L. Ren, Z. Li, Y. Yao, X. Lin, W. Ding, A.C. Ferrari, J. Zou. Nano-Micro Letters, 18, 94 (2026).
News article by Dr Karen Steward