Modeling of the hydrogen sorption kinetics in an AB2 laves type metal hydride alloy

• Isothermal hydrogen sorption kinetics of Zr-Ti based AB 2 alloy hydride is modeled. Effect temperature and pressure on the single step multiple steps kinetics. The rate limiting for jointly defined by H diffusion a nucleation growth mechanism hydride. Hydrides Laves type alloys (A=Zr, Ti; B = transition metal – Fe, Co, Ni, Mn, Cr, V) have been extensively studied as materials storage gaseous hydrogen. They contain up to 4 atoms/formula unit , thus achieving reversible capacities in range between 1.5 2.0 wt% offering high rates charge discharge, making them suitable designing efficient stores operating at ambient conditions. In present study, we performed an experimental study modeling thermodynamics interaction -hydrogen system. data was collected studying model with composition Ti 0.15 Zr 0.85 La 0.03 Ni 1.126 Mn 0.657 V 0.113 Fe . Hydrogen absorption desorption were volumetric Sieverts apparatus isothermal conditions using single-step change/discharge stepwise methods. results obtained from simulation show that reaction follows Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, value exponent n 1–1.25 1 desorption. This indicates rate-limiting are governed grain boundary alpha-solid solution beta-hydride. activation energies both decrease along increasing content