Enhanced electrochemical hydrogen storage performance of TiVNi composite employing NaAlH4

The Ti 1.4 V 0.6 Ni doped with NaAlH 4 composites were prepared by ball-milling method and the phase composition and electrochemical hydrogen storage properties of the composites were investigated. The phase contains icosahedral quasicrystalline (i-phase), Ti 2 Ni and V-based solid-solution phase primarily. The NaAlH 4 phase is not evident for the composite, and the NaAlH 4 phase should be decomposed to help form porous structure on the surface of the composites. The electrochemical hydrogen storage properties of composites has been enhanced with doped NaAlH 4 , and the maximum electrochemical hydrogen discharge capacity is 299.2 mAh/g, and keeps above 220 mAh/g after 80 cycles for 1 wt.% doping. The high-rate discharge ability of the composite electrode could achieve 79.8% at the discharge current density of 240 mA/g compared with that of 30 mA/g. The enhancement could be attributed to decoration of the composites surface, increase of entropy variation and improvement of H-kinetics on the strength of new porous structure in the composites.