Water Resistant Hydrogen Storage Alloys Encapsulated with Sol-Gel Derived Shells
2006 Volume 31 Issue 1 Pages 38-43
Details
2006 Volume 31 Issue 1 Pages 38-43
In order to impart resistance against water vapor, a Laves phase alloy, (Ti0.5Zr0.5)(Fe0.2Mn0.8)1.5, was encapsulated by ceramic cover layer derived from tetraethoxysilane (TEOS), which was one of the raw materials for sol-gel encapsulating method developed earlier. Although TEOS treated samples showed substantially no capacity loss under humidified hydrogen (partial pressure of water: 0.61 kPa), they showed unfavorable increase in apparent equilibrium pressures. Another problem to be resolved was lack of cyclic durability. Isotherms for TEOS treated samples approaches those for untreated ones through cycling. An improvement comprising introduction of rubber-like segments into sol-gel capsules brought about durability on cycling. Extrinsic loss of hydrogen capacity was minimized for a typical BCC alloy, Ti0.1Cr0.1V0.8, which was assessed by a temperature swung hydriding-dehydriding cycles.
