Comprehensive hydrogen storage properties of free-V Ti1-xZrxMn0.9Cr0.7Fe0.1 alloys with different Zr substitution content

Hydrogen has been widely recognized as a promising new renewable energy source. Developing safe and efficient hydrogen storage technologies is crucial for scaling up hydrogen energy applications. AB2-type Ti–Mn-based hydrogen storage alloys have excellent kinetic and activation properties, but their comprehensive hydrogen storage performance, especially the hydrogen storage capacity, platform pressure, and cycling stability of low-cost Ti–Mn-based alloys without V, needs to be further optimized. Hence, the hydrogen storage properties of the Ti1-xZrxMn0.9Cr0.7Fe0.1 (x ​= ​0.05, 0.16, 0.20, 0.25) were systematically studied. All of the series alloys contained a single C14-type Laves phase structure. Increasing the substitution of Zr for Ti resulted in higher hydrogen storage capacities and lower plateau pressures. Notably, the effective hydrogen storage capacity of x ​= ​0.16 alloy is significantly higher than that of the other alloys, and its platform pressure is the most suitable. This alloy achieved a hydrogen content of 1.8 ​wt% and demonstrated excellent cycling stability, retaining 98.6 ​% of its capacity after 100 cycles. This study provides a theoretical guideline for optimizing the properties of low-cost TiMn-based alloys without V.