Studies On Synthesis Of Vanadium Base Solid Solution Hydrogen Alloy And Its Performance

Vanadium-based solid solution alloys became study hotspot because of their high hydrogen storage capacity and diffusion rate. Nowadays,Vanadium-based solid solution alloys manufacture mainly adopt pure Vanadium,Titanium and other raw materials and use vacuum electric arc or vacuum response smelt way to produce ,but the price of pure Vanadium is very expensive, it prevent the exploitation and appliance of Vanadium-based solid solution alloys. The Self-propagating High-temperature Synthesis technology to produce vanadium-based solid solution hydrogen storage alloys was investigated. Taking V2O5,TiO2 ,Cr2O3 as raw materials and Al as a reductive agent, V3TiNi0.56Al0.2 ,V3TiNi0.56Al0.1Crx(x=0.1-0.3) can been produced by SHS technology. the microstructure,hydrogen capacity and electrode properties of Vanadium-based solid solution hydrogen storage alloys are analyzed, the study results as following: (1) The adiabatic combustion temperature Tad of V3TiNi0.56Al0.1Crx(x=0.1-0.3) and V3TiNi0.56Al0.2 is about 2584-2879K, which testify the process of the Self -propagating can sustain. (2) It has been found that V3TiNi0.56Al2.3 alloy produced by SHS consists of two phases, the mian phase is a (Ti,V) solid solution with body centered cubic (b.c.c) structure,the secondary phase is a TiNi-based phase with a b.c.c structure containing TiNi and Ti2Ni, the secondary phase is precipitated and formed a three-dimensional network along grain boundaries of (Ti,V) solid solution main phase. Some oxides such as Al2O3, CaAl2O4, CaAl4O7, V2O3 is also found in the alloy. The treatment of anneal make the chemical compositions of the alloy is more homogeneous. After water quench treatment, the amount of the secondary phase in the alloy increases. (3) the alloy produced by SHS has the reversible hydrogen storage property,at 25℃,the equilibrium pressure is 0.01MPa, hydrogen storage capacity of V3TiNi0.56Al0.2 alloys D# and C# by SHS is respectively 1.526wt%and 0.805wt%. (4) The discharge capacity for V3TiNi0.56Al0.1Cr0x (x=0.1-0.3) alloy is 150mAh/g to 260mAh/g. however, the attenuation of discharge capacity is rapidly. The cyclic voltammetry experiments indicate that the alloy has a distinct anodic peak, but the anodic current decreases with the increasing of cycles.