Safe Hydrogen storage at room temperature

Hydrogen-powered cars that do not pollute the environment are a step closer thanks to a new discovery which promises to solve the main problem holding back the technology. Whilst hydrogen is thought to be an ideal fuel for vehicles, producing only water on combustion, its widespread use has been limited by the lack of a safe, efficient system for onboard storage. Scientists have experimented with ways of storing hydrogen by locking the gas into metal lattices, but metal hydrides only work at temperatures above 300°C and metal organic framework materials only work at liquid nitrogen temperatures (-198°C). Now scientists at the University of Bath have invented a material which stores and releases hydrogen at room temperature, at the flick of a switch, and promises to help make hydrogen power a viable clean technology for the future.

Although its fuel to weight ratio is insufficient to make an entire hydrogen tank from it, the material could be used in combination with metal hydride sources to store and release energy instantaneously whilst the main tank reaches sufficient temperature, 300°C, to work.

They hope to have the fully-working prototype ready within two to three years.

“The problem of how to store hydrogen has been a major bottleneck in the development of the hydrogen power technology,” said Dr Andrew Weller from the Department of Chemistry at the University of Bath (UK).

“Hydrogen has a low density and it only condenses into liquid form at -252°C so it is difficult to use conventional storage systems such as high-pressure gas containers which would need steel walls at least three inches thick, making them too heavy and too large for cars.

“The US Department of the Energy has said that it wants six per cent of the weight of hydrogen storage systems to be hydrogen in order to give new hydrogen powered cars the same kind of mileage per tank of fuel as petrol-based systems.

“Whilst metal hydrides and metal organic framework materials can achieve this kind of ratio, they only work at extremes of temperature which are difficult to engineer into an ordinary vehicle.

“Our new material works at room temperature and at atmospheric pressure at the flick of a switch. Because it is made from a heavy metal (Rhodium), its weight to fuel ratio is low, 0.1 per cent, but it could certainly fill the time lag between a driver putting their foot on the accelerator and a metal hydride fuel tank getting up to temperature.

“We are really very excited about the potential this technology offers.”

...continued