2014 Volume 55 Issue 8 Pages 1138-1140
Recently, LiAlH4 has attracted attention as one of the most promising hydrogen storage materials, because LiAlH4 is able to release large amount of hydrogen (7.9 mass%H2) below 250°C. However, the kinetics of the dehydrogenation reaction of LiAlH4 is too slow for applications to fuel cell vehicles. To improve the dehydrogenation kinetics, the dopant effect of TiCl3 has been investigated in this research. Here, LiAlH4 doped with various ratios (0, 0.1, 0.2, 0.5, 1.0, and 2.0 mol%) of TiCl3 were prepared by ball milling for 30 min under a 1.0 MPa H2 atmosphere. The decomposition of LiAlH4 proceeds via a two-step reaction and the dehydrogenation kinetics of each step were compared to determine the optimum amount of TiCl3 that would assist the process. With increasing of TiCl3 amount, the dehydrogenation temperature for both of the reactions decreased. Activation energies decreased with increasing TiCl3 amount, however the amount of desorbed hydrogen decreased. Considering the kinetics and hydrogen capacity in the both steps, the results suggest that the optimum amount of doped TiCl3 for the dehydrogenation of LiAlH4 is around 0.2 mol%.
