A Comparative Study on the Structure and Absorption Properties of Thin-Film Hydrogen Storage Materials Based on Mg-N-H and $(\mathrm{V}_{0.9}\text{Ti}_{0.1})-\mathrm{N}-\mathrm{H}$

Abstract

Nanocrystalline and nanoporous structures have been identified as a promising hydrogen storage solid material for fuel cell systems. Limited grain sizes and a branched system of grain boundaries are providing favorable conditions for acceleration and facilitation of the hydrogen diffusion and accumulation. In addition, the nanoporous structures have good gravimetric properties. This study reports on the accumulation and release of the large amounts of hydrogen by nanocrystalline Mg-N-H and nanoporous $\left(\mathbf{V}_{0.9} \mathbf{T i}_{0.1}\right)-\mathbf{N}-\mathbf{H}$ thin-film structures. A comparison of the structural changes during the hydrogen absorption and desorption has been carried out. The research revealed the relationship between the electrical resistance of investigated films and the amount of the hydrogen contained in them. It is shown that nano-porous $(\mathrm{V}_{0.9} \text{Ti}_{0.1})-\mathrm{N}-\mathrm{H}$ films have better kinetic properties than nanocrystalline Mg-N-H films, while their gravimetric and thermodynamic properties are broadly similar.