Hydrogen Storage Properties Of V Based Binary Alloys

In this thesis, based on many literatures in the related academic domain, V-M (M=Ni, Fe, Cr) binary alloys were studied, trying to find some guide for multinary alloy. The effects of Ni, Fe or Cr on the activation performance, kinetic property, desorption PCT capacity, the capacity and stability ofβphase andγphase of V-based solid solution that has two plateau pressures. And transformation of phase structure during absorption and desorption were investigated. The main results are presented as follows:(1) About V_100-xNi_x (x=0～12at%) binary alloy. The activation performance and the absorption kinetic of vanadium are improved by the addition of Ni. With the increase of Ni content, the desorption pressure of high pressureγphase increases, and the stability of the alloy decreases. When Ni content in the alloy is higher than 0.5at%, H content inγphase decreases rapidly, and when Ni content is higher than 2 at%,γphase vanishes under 293K,3MPa. Ni addition in V metal leads to the hydrogen capacity decrease of low pressureβphase and hydrogen desorption pressure increase ofβphase. At the same time, the alloy's lattice parameter declines in a linear way with the increase of Ni content.(2) About V_100-xFe_x (x=0～2at%) binary alloy. The activation performance and plateau pressure of vanadium are improved by the addition of Fe, while the absorption and desorption capacities are declined. When the addition of Fe content is lower than 1at%, it has not influence on the properties of di-hydrideγphase. When Fe addition > 1at%, the plateau pressure of di-hydrideγphase increases, the absorption and desorption capacities and hydride formation enthalpy of di-hydrideγphase decrease obviously. However, the addition of Fe influences little on the properties of mono-hydrideβphase of vanadium. The lattice parameter and lattice volume of vanadium declines in a linear way with the increase of Fe addition.(3) About V_100-xCr_x (x=0～15at%) binary alloy.The hydrogen absorption kinetic performance and plateau pressure of vanadium are improved with the addition of Cr. When Cr addition is no more than 6at%, it has little influence on the absorption-desorption capacities ofγphase, but increases the high plateau pressure; when Cr addition is larger than 6at%, the hydrogen storage capacities of di-hydridesγphase decrease obviously, and, the plateau pressure still increases; the addition of Cr increases the plateau pressure of mono-hydrideβphase. The lattice parameter and cell volume of vanadium declines in a linear way with the increase of Cr addition.(4) The effects of the activation performance, kinetic property, desorption PCT capacity were investigated when the adding content is the same among different added elements, some regularities were found. The lattice parameter and electron concentration are the reasons that caused the differences of hydrogen absorption and desorption capacities, but there are still other reasons that wait for further study.