Improvement of the LiBH 4 hydrogen desorption by inclusion into mesoporous carbons

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LiBH 4 hydrogen desorption is strongly improved by its confinement to the nanoscale into a mesoporous carbon, prepared by the template method, having a pore diameter near 4 nm and a porous volume of 1.1 cm 3 g −1. The LiBH 4/carbon composites are prepared by room temperature impregnations of the carbon matrix with LiBH 4 solubilized within ethers. LiBH 4/carbon composites with a 33:67 weight ratio show excellent desorption kinetics with a hydrogen release of 3.4 wt.% in 90 min at 300 °C, whereas the decomposition of neat LiBH 4 is not significant at the same temperature. Moreover, both Differential Scanning Calorimetry and Thermal Desorption Spectroscopy experiments show that the hydrogen release for the 33:67 LiBH 4/carbon composite occurs in one single step immediately above the LiBH 4 melting temperature (280 °C) without any formation of intermediate compounds (like dodecaborane) as encountered with neat LiBH 4. Such modification of the hydrogen release mechanism path was never reported for confined LiBH 4 nanoparticles. Last the presence of the carbonaceous matrix is expected to be largely beneficial for handling the heat transfer associated with the endothermic character of the LiBH 4 decomposition process.