Improved dehydrogenation and rehydrogenation properties of LiBH₄by nanosized Ni addition

The complex hydride LiBH₄, with a hydrogen density of 18.5 mass%, has been attracting significant interests for hydrogen storage, while suffers from its high dehydrogenation and rehydrogenation temperature. In this work, we systematically investigated the improvement effects of nanosized Ni on the dehydrogenation and rehydrogenation reactions of LiBH₄using thermogravimetry, quadrupole mass spectrometry and pressure-composition-isotherm analyses. Nanosized Ni was homogeneously dispersed on the surface of LiBH₄after ball milling. The dehydrogenation peak temperature of LiBH₄was reduced from 743 to 696K with addition of 25 mass% Ni. First, LiBH₄tended to react with Ni to form Ni₄B₃, which suggests the thermodynamic destabilization effect of Ni. Then, the in-situ formed Ni4B3 was suggested to play a catalytic role on the dehydrogenation of the unreacted LiBH₄. Moreover, the rehydrogenation content of LiBH₄was improved from 4.3 to 10.8 mass% by addition of 25 mass% Ni, suggesting the significant improvement effect of Ni₄B₃on the rehydrogenation.