Hydrogen absorption and re-emission characteristics of metal-oxide bi-layer composite materials measured by ion beam analysis

Hydrogen absorption and emission characteristics of Pt-Li ₂ZrO₃ bi-layer materials exposed to normal air at room temperature have been studied by means of elastic recoil detection analysis(ERD), Rutherford backscattering spectroscopy (RBS), weight gain measurement (WGM) and thermal desorption spectroscopy (TDS). The Pt/Li ₂ZrO₃/Pt sandwich specimens have been found to absorb H at the Pt surface from H₂O vapor, store it in Li₂ZrO ₃, and emit 80% of it as H₂ gas, when they are heated at 100 °C for 10 min. Data obtained by WGM shows that the weight gain increases linearly with increasing the exposure time. TDS analysis also shows that the main species of gases re-emitted are H₂ and H₂O. Moreover, the hydrogen storage rate in Li₂ZrO₃ is shown to be controlled by the hydrogen absorption rate at the Pt surface, based on the hydrogen absorption and storage model proposed. The maximum storage capacity of Li₂ZrO₃ has been estimated to be 0.15 Nl/cm³ from the saturation hydrogen concentration, (1/2)H/Li₂ZrO ₃, measured by means of the ERD technique.