Hydrogen absorption and emission characteristics of Pt/Li ₄SiO ₄/Pt hydrogen storage materials exposed to air at room temperature

Hydrogen storage and emission characteristics of Pt/Li ₄SiO ₄/Pt composite materials exposed to normal air at room temperature have been studied by means of elastic recoil detection analysis, RBS, and weight gain measurement techniques. The thermal annealing curves of Pt/Li ₄SiO ₄/Pt sandwich specimens with Pt layers of 1 and 10 nm in thickness measured by elastic recoil detection technique indicate that the hydrogen emission of residual hydrogen takes place in the two stages, and 70% of hydrogen retained is emitted at the first stage, which finishes at a temperature of ∼350 K. The hydrogen storage curves at the first run indicate that the saturation storage levels of the specimens of 1 and 10-nm Pt layers pre-heated at 423 K are 12 wt.% and 14 wt.%, respectively. The hydrogen storage curve of the specimen with 10 nm Pt layers annealed at temperature of 773 K indicates that the initial slope of the weight gain is considerably larger than that at the first run. This fact seems to indicate that the high temperature annealing brings about enhancement in the absorption rate caused by formation of Pt-Si-Li-O complex oxides through the interfacial reaction between the Pt layer and Li ₄SiO ₄.