Reversible hydriding and dehydriding properties of CaSi: Potential of metal silicides for hydrogen storage

Abstract

We found that CaSi reversibly absorbs and desorbs hydrogen. First-principles calculations theoretically indicated that CaSi hydride is thermodynamically stable. The hydriding and dehydriding properties of CaSi were experimentally determined using pressure-composition (p-c) isotherms and x-ray diffraction analysis. The p-c isotherms clearly demonstrated plateau pressures in a temperature range of 473–573K. The maximum hydrogen content was 1.9wt% under a hydrogen pressure of 9MPa at 473K. The reversible hydriding and dehydriding properties of CaSi suggest the potential of metal silicides for hydrogen storage.