The effect of carbon and silicon-based additives on the hydrogen storage properties of Lithium Borohydride

Vines, Joshua Edwin (2017). The effect of carbon and silicon-based additives on the hydrogen storage properties of Lithium Borohydride. University of Birmingham. Ph.D.

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Abstract

LiBH $_4$ was added to a number of different non-reactive additives in order to investigate their influence on the hydrogen storage properties of LiBH $_4$ .
Graphite is a cheap and abundant material that has been used to destabilize hydrogen storage materials such as LiH. Ball milling graphite under Ar was shown to induce a higher amorphous content compared to milling under H $_2$ . The addition of LiBH $_4$ to graphite milled under Ar resulted in a reduction of 102°C in the decomposition temperature of
LiBh $_4$ .
The effect of porous additives was investigated through the incorporation of LiBH $_4$ into zeolite templated carbon (ZTC) and porous silicon. Confinement in these scaffolds resulted in a decrease in the decomposition temperature of LiBH $_4$ by 125°C. The smaller pore size of ZTC was found to have the greatest effect on the H $_2$ onset and cyclic stability of LiBh $_4$ .
The pre-melting of LiBh $_4$ into porous scaffolds was shown to eliminate B $_2$ H $_6$ release during decomposition. No correlation between the surface area of the additives and decomposition temperature of LiBH $_4$ was observed. Although none of the materials studied in this work meet the United States DoE targets, confinement of LiBH $_4$ in porous structures offers a promising approach to unlocking its potential.