Improvement of hydrogen storage properties of TiCrV alloy by Zr substitution for Ti

The effects of Zr substitution for Ti on the hydrogen absorption–desorption characteristics of Ti1−xZrxCrV alloys (x = 0, 0.05, 0.1 and 1.0) have been investigated. The crystal structure, maximum hydrogen absorption capacity, kinetics and hydrogen desorption properties have been studied in detail. While TiCrV crystallizes in body centered cubic (BCC) structure, ZrCrV is a C15 cubic Laves phase compound and the intermediate compositions with 5 and 10 at% Zr substitutions for Ti (x = 0.05 and 0.1) show the presence of a small amount of ZrCr2 Laves phase along with the main BCC phase. The pressure–composition isotherms have been studied at room temperature. TiCrV shows separation of TiH2 phase on cycling. A small amount of Zr substitution for Ti is found to have advantageous effects on the hydrogen absorption properties of TiCrV as it suppresses TiH2 phase separation and decreases hysteresis. It is found that the hydrogen absorption capacity of Ti1−xZrxCrV decreases as the Zr content increases due to the increased fraction of Laves phase. Temperature-programmed desorption studies have been carried out on the saturated hydrides in order to find the relative desorption temperatures.