Effect of Ti Compounds on Hydrogen Desorption/Absorption of LiNH2/LiAlH2/MgH2

Abstract

The effect of Ti compounds on H2 desorption/ absorption of LiNH2/LiAlH4/MgH2 was investigated. The formation of NH3 from the decomposition of LiNH2 was suppressed by adding LiAlH4 and MgH2 to LiNH2. In addition, the onset desorption temperature of LiNH2/LiAlH4/MgH2 was lower than that of pure LiNH2, whose onset desorption temperature is approximately 473 K. It was observed that the reversibility of the ternary mixture improved when Ti compounds (TiO2, TiCl3, and Ti) were doped into it. The Ti-doped mixture exhibited the highest reversible H2 capacity (0.4 wt%) at 573 K. Small peaks corresponding to Mg(AlH4)2 and Mg(NH2)2 were revealed from the XRD patterns of the ternary mixture, and the presence of reversible phases in the mixture were indicated from these peaks.