Hydrogen is poised to become the fuel of the future, but to make that happen, a safe and efficient way to store it needs to be found. Conventional pressurized tanks are costly and potentially dangerous, which typically leaves either chemisorption — storing hydrogen using reversible chemical reactions — or physisorption — storing hydrogen using van der Waals forces — as the only viable alternatives.

However, these methods have their own limitations that make them challenging to implement. The hydrogen interactions need to be strong enough to trap the hydrogen but not so strong that it is difficult to get it back out. Physisorption methods are typically too weak and fall short of this sweet spot, while chemisorption is often too strong.

Liu et al. reviewed a collection of methods that fall into neither category and have the potential to store hydrogen more efficiently.

“We describe four nonclassical hydrogen storage mechanisms, in which the Kubas interaction and the nanopump effect show exciting comprehensive hydrogen storage performances, including high capacity, fast kinetics, and ambient temperature operation,” said author Jianglan Shui.

The researchers are particularly excited about methods involving the nanopump effect, as it can be exhibited by a wide range of materials and has the potential to be extremely versatile and cost effective. In general, they hope these alternate methods will allow dense, ambient temperature storage of hydrogen for the future.

“We hope some of new hydrogen storage materials can be put into practical use in the near future to help the development of hydrogen economy,” said Shui.

Source: “Non-classical hydrogen storage mechanisms other than chemisorption and physisorption,” by Shiyuan Liu, Jieyuan Liu, Xiaofang Liu, Jia-Xiang Shang, Ronghai Yu, and Jianglan Shui, Applied Physics Reviews (2022). The article can be accessed at https://doi.org/10.1063/5.0088529.