Climate change and cost-effective energy supply are the toughest challenges facing the human race for decades to come. Hydrogen is a clean energy carrier to power fuel-cell vehicles and domestic appliances. Safe and practical storage of hydrogen is regarded as a critical enabling step towards a hydrogen-driven economy / the long-term solution to containment of global warming. Many storage options and materials have been studied and tested with specific practical targets for high capacity and rapid hydrogen charging/discharging at relatively low temperatures. Various progresses have also been made but are still some distance away from the targets.
Mg-based hydrides continue to attract large attention for hydrogen storage, due to its relatively high storage capacity (~6.7 mass%), reversibility, and low-cost. This is particularly useful for stationary and domestic applications, where rapid sorption kinetics and availability at low cost are more important than capacity. The main issues are its high stability and slow sorption kinetics. The main aim of this project is to further improve its thermodynamic and kinetic properties by extended particle refinement, via. cryogenic milling and a novel vortex-driven high-energy pulverisation process. The techniques can provide ultra-clean and high surface area nano-particles with selective additions of dopants and catalysts. A particle coating method will also be investigated to maximize the catalytic effect. With particular consideration of practical applications, both the tolerance of Mg to impurities in hydrogen and the viability of using Mg as a down-stream storage and "purification" medium will be investigated for an industrial hydrogen generation process.
The novelty of the proposal lies in the use of novel high-energy milling, doping and catalytic coating for the improvement of sorption properties of Mg-based hydrides. The catalytic effect of transitional metal carbides on hydrogen sorption has not been considered in the past, though proved in other processes. The idea of applying a catalytic coating not only makes full use of the catalysis function, but also effectively stops powder growth, stabilizing the hydrogen storage structure for improved cyclability. Possible effects of impurities on hydrogen sorption have not been reported before, and are very important for industrial considerations.
This project is of great benefit to the understanding of hydrogen interactions with metals and nanostructures. The developed materials will particularly benefit the industrial collaborators and UK companies working on renewable energy resources. The investigation is particularly suited for practical hydrogen storage, where tolerance of gas impurities is as important as high sorption kinetics and capacity. Exploitation of hydrogen energy can resolve many pressing and conflicting issues, such as increasing energy demand, global warming, energy security, and urban pollution, which is of great benefit to the environment and to the health of the public.