The enhanced thermal conductivity and hydrogen storage performance of Ti-Fe-Mn alloy pellet using Al filler

TiFe-based hydrogen storage alloys face several challenges, including low thermal conductivity, low mechanical stability, and inadequate hydrogen storage kinetics. In the present work, Al was selected as a filler in an attempt to address the aforementioned issues with TiFe-based alloys. Pellets of the Al-added Ti₁.₁Fe₀.₈Mn₀.₂ alloy present the quantitative enhancement of thermal conductivity (from 12.5 to 18.2 W/(m·K)) through pore-filling and intrinsic high conductivity of Al. Al also remarkable reduces activation energy for hydrogen absorption (from 20.4 to 11.0 kJ/mol) and desorption (from 42.6 to 38.2 kJ/mol) of Ti₁.₁Fe₀.₈Mn₀.₂ alloy. The phenomenon should come from the Al-induced surface electronic structure modulation where the formation of Fe²⁺ causes negative shifts in binding energies to improved catalytic activity. Furthermore, Al addition can improve mechanical strength, which increases maximum compressive stress increased to 230.6 MPa and enhances the cycling stability. These synergistic improvements in thermal conductivity, kinetics, and mechanical stability demonstrate that Al filler is a highly effective multifunctional additive for overcoming the major limitations of TiFe-based hydrogen storage alloys.