Question

Calculate the percentage of hydrogen in metal hydride

Answer 1

The most frequently quoted hydrogen content quantity, in terms of storage applications, is wt.%: the weight percent capacity or the gravimetric storage density of a material. The calculation or definition of this quantity differs between hydrogen absorbers and adsorbents; although it is more clearly defined in the former case, there is some uncertainty associated with both quantities due to the definition of either the sample volume or density, and the effect of hydrogen sorption on this quantity.

In both cases, there are sorption measurement-related issues associated with the choice of hydrogen capacity definition that are important to consider. This brief article summarizes some of the definitions, and the associated problems.