Improved Dehydrogenation and Rehydrogenation Properties of LiBH₄ by Nanosized Ni Addition (Special Issue on Advanced Materials for Hydrogen Energy Applications(2)) Improved Dehydrogenation and Rehydrogenation Properties of LiBH<sub>4</sub> by Nanosized Ni Addition
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The complex hydride LiBH<sub>4</sub>, 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 LiBH<sub>4</sub> using thermogravimetry, quadrupole mass spectrometry and pressure-composition-isotherm analyses. Nanosized Ni was homogeneously dispersed on the surface of LiBH<sub>4</sub> after ball milling. The dehydrogenation peak temperature of LiBH<sub>4</sub> was reduced from 743 to 696 K with addition of 25 mass% Ni. First, LiBH<sub>4</sub> tended to react with Ni to form Ni<sub>4</sub>B<sub>3</sub>, which suggests the thermodynamic destabilization effect of Ni. Then, the <i>in-situ</i> formed Ni<sub>4</sub>B<sub>3</sub> was suggested to play a catalytic role on the dehydrogenation of the unreacted LiBH<sub>4</sub>. Moreover, the rehydrogenation content of LiBH<sub>4</sub> was improved from 4.3 to 10.8 mass% by addition of 25 mass% Ni, suggesting the significant improvement effect of Ni<sub>4</sub>B<sub>3</sub> on the rehydrogenation.
- MATERIALS TRANSACTIONS
MATERIALS TRANSACTIONS 55(8), 1134-1137, 2014
The Japan Institute of Metals and Materials