  Complex light metal hydrides possess many properties which make them
attractive as a storage medium for hydrogen, but typically, catalysts are
required to lower the hydrogen desorption temperature and to facilitate
hydrogen uptake in the form of a reversible reaction. The overwhelming focus in
the search for catalysing agents has been on compounds containing titanium, but
the precise mechanism of their actions remains somewhat obscure. A recent
experiment has now shown that fullerenes (C$_{60}$) can also act as catalyst
for both hydrogen uptake and release in lithium borohydride (LiBH$_4$). In an
effort to understand the involved mechanism, we have employed density
functional theory to carry out a detailed study of the interaction between this
complex metal hydride and the carbon nanomaterial. Considering a stepwise
reduction of the hydrogen content in LiBH$_4$, we find that the presence of
C$_{60}$ can lead to a substantial reduction of the involved H-removal
energies. This effect is explained as a consequence of the interaction between
the BH$_x^-$ complex and the C$_{60}$ entity.
