Effect of La Doping on Kinetic and Thermodynamic Performances of Ti_1.2CrMn Alloy upon De/Hydrogenation

Abstract

Development of efficient hydrogen storage materials is one of the great challenges in the area of hydrogen energy and fuel cells. Herein, a La-doped Ti 1.2 CrMn alloy with high hydriding capacity (2.1 wt % H) and dehydriding capacity (1.8 wt % H) was successfully developed. The crystallographic characteristics, microstructural evolution, and hydrogen storage mechanisms of the alloy were investigated systematically. It was found that the introduction of La increased the cell volume of alloy and thus improved the hydrogenation kinetic, practical hydrogenation capacity, and cyclic property. The hydrogenation kinetic results of the La-doped alloy indicate that it exhibited a higher hydrogenation rate than that of the La-free alloy. It is ascribed to the formation of LaH 3 , which provides a fast diffusion channel for hydrogen atoms to enter the alloy matrix. The dehydrogenation enthalpy (ΔH) of the La-doped alloy was calculated by the van't Hoff equation and PCT curves to be ∼18.2 kJ/mol. The cycle test proves that the La-doped Ti 1.2 CrMn alloy, due to La addition, reduces the lattice expansion and lattice stress and exhibits excellent durability.

Development of V-Free BCC Structured Alloys for Hydrogen Storage

“…Substituting part of Cr with Fe reduces the plateau pressure but slightly decreases the maximum storage capacity . Introducing Mn decreases the hysteresis factor but lowers the plateau pressure . Modification with Cu and Ni enhances activation performance but decreases storage capacity. , In contrast, V substitution in TiCr-based alloys improves storage performance, achieving a higher effective dehydriding capacity of up to 2.4 wt % .…”