The hydrogen ab/desorption kinetic properties of doped magnesium hydride MgH2 systems by first principles calculations and kinetic Monte Carlo simulations

Hydrogen storage ab/desorption kinetic properties of MgH2 and MgH2 doped with different metal M (M = Al,Ti,V,Fe and Ni) are investigated by using both DFT method and kinetic Monte-Carlo simulations. The first principles calculations show that the energy barriers decrease considerably when doping with a small amount of M element leading to a decreasing of both the stability and the decomposition temperature of the material. Based on the activation energies computed from DFT calculations, we show within the kinetic Monte-Carlo method that the ab/desorption time is reduced considerably without reducing much the hydrogen storage capacity of the material. From our analysis, we observed that the Ni element exhibits the most appropriate thermodynamical properties for hydrogen storage and the best kinetic of hydrogen absorption/desorption.