High pressure hydrogen compression exploiting Ti1.1(Cr,Mn,V)2 and Ti1.1(Cr,Mn,V,Fe)2 alloys

Abstract

For metal hydride compressors to be used in substitution to the mechanical ones in the hydrogen infrastructures, it is mandatory to develop new compositions that can satisfy the desired goal of a pressure of 700 bar. To achieve the goal, Laves (C14) intermetallic compounds Ti(Cr,Mn)2-based are very promising. New Ti1.1(Cr,Mn,V)2 and Ti1.1(Cr,Mn,V,Fe)2 compositions were synthetized and characterized in this work. The influence of the substitution of Cr with Mn and Fe on the crystal structure, and its correlation with the hydrogen sorption properties, was investigated, detecting an increment in the plateau pressure and the hysteresis gap. Thanks to suitable thermodynamics, developed alloys are good candidates for the high-pressure hydrogen compression. Moreover, they present an easy activation, that can be performed at room temperature, and a fast reaction rate, with few seconds required to absorb about 90% of the hydrogen content in the alloy. The most promising composition is the Ti1.1Cr0.9Mn0.8V0.1Fe0.2, that is estimated to release hydrogen at about 700 bar at 150 °C. A possible integration of developed alloy in a metal hydride compressor is evaluated.