A novel methodology for enhancing hydrogen storage kinetics property of Ti37V40Mn23 + 10 wt% Zr8Ni21 alloys: Effect of ultrasonic treatment

Abstract

Renewable energy sources are intermittent by nature, requiring efficient energy storage technologies to ensure stable supply. Hydrogen storage alloys, with their high safety, high energy density, and reversibility, can convert excess energy into hydrogen for storage and later use. In this work, Ti₃₇V₄₀Mn₂₃ + 10 wt% Zr₈Ni₂₁ alloy was prepared by arc-melting and ultrasonic treatment technology, establishing fundamental correlations between preparation process, microstructure, and storage kinetics. Ultrasonically-treated (UST) alloys consisted of BCC and C14 Laves phases. The phase evolved from columnar crystals to equiaxed grains with the extension of treatment time. The alloy UST for 180s (Alloy-3) exhibited improved ab-/desorption kinetics, with hydrogen absorption capacity of 3.06 wt% and desorption capacity of 2.08 wt% at 303 K. The activation energy required for the dehydrogenation process in Alloy-3 was measured to be 47.22 kJ/mol, indicating that the surface hydrogen desorption reaction was more likely to reach an active state. Ultrasonic treatment enhanced the hydriding and dehydriding rate by refining BCC phase grains and increasing the specific surface area, which provided additional sites for the adhesion and reaction of H atoms. Furthermore, the enthalpy values (ΔH) were computed using van't Hoff equation. Ultrasonic treatment improved the hydride stability of the alloys.