Storing solid hydrogen for energy applications

Hydrogen is naturally abundant, volatile gas at room temperatures – but when used as a fuel source it produces no pollution, making it a favourite of those investigating a clean energy future.

A team from The University of Queensland’s Nihon Superior Centre for the Manufacture of Electronic Materials (NSCMEM) and Kyushu University, Japan, is helping to overcome the issue of safely storing the volatile gas and efficiently retrieving it when it’s needed.

The researchers have taken steps towards developing a viable hydrogen fuel cell by realising that it’s easier to collect stored hydrogen when there are defects within the storage device.

The team is investigating solid-state gas storage – a safer, more practical, and potentially less energy-intensive mechanism to store hydrogen compared to conventional alternatives that include compressing the gas or cryogenically cooling it.

Binding hydrogen atoms to a metal alloy keeps them in a solid state. Once bonded, the hydrogen is retained in a stable crystalline structure, where it waits until it’s retrieved.

Retrieval brings problems of its own. It requires energy – often either heat or electrical – to release hydrogen from its binding. The more energy that’s required to remove the hydrogen, the less efficient the entire system becomes.

Using ANFF-Q’s Differential Scanning Calorimetry capabilities, the team monitored the temperature required to break the hydrogen free from samples of magnesium-nickel, an appealing storage material due its high storage capacity, low cost, and availability.

One finding of the team’s research is that the areas of the storage medium containing defects release hydrogen at temperatures at least 100ºC lower than those regions with no defects. This information arms cell manufacturers with a means to reduce the energy required to withdraw hydrogen from storage, improving efficiency and making the process easier.

“This research has been funded by a Brisbane-based hydrogen storage company, Hydrexia Pty Ltd., to further the understanding of their proprietary materials in order to improve the system performance outputs such as faster hydrogen uptake/release rates, lower operating temperatures, and more,” Xuan Quy Tran, a scientist at NSCMEM and lead author of the research, said.