To date, none of H₂ storage approaches have reached the 2015 US Department of Energy’s (DOE) targets of 5.5 wt % and 40 kg/m³. In 2010, David Antonelli and colleagues, University of Windsor, Ontario, Canada, reported Cr and V hydrazide gels for hydrogen storage. These materials fell short of practical applications due to residual ligands from the precursor remaining in the structure, blocking coordination sites that could be used for hydrogen binding.

The team now reports that hydrogenation of the Cr hydrazide gels removes the residual ligands and leads to a dramatic increase in performance. The material with the highest capacity had an excess reversible storage of 3.23 wt % at room temperature, corresponding to 40.8 kg H₂/m³.

This provides a promising new class of hydrogen storage materials.

• Hydride-Induced Amplification of Performance and Binding Enthalpies in Chromium Hydrazide Gels for Kubas-Type Hydrogen Storage
  A. Hamaed, T. K. A. Hoang, G. Moula, R. Aroca, M. L. Trudeau, D. M. Antonelli,
  J. Am. Chem. Soc. 2011.
  DOI: 10.1021/ja2021944