Hydrogen solubility and diffusion studies of Zr-based AB2 alloys and sol–gel encapsulated AB2 alloy particles

A comparative study on the hydriding kinetics of Zr-based AB2 hydrogen storage alloys

“…2, correspondingly. The calculated apparent activation energies of the hydriding reaction are 26.9 kJ/mol H 2 for Ti 0.1 Zr 0.9 Mn 0.9 V 0.1 Fe 0.5 Co 0.5 , 39.5 kJ/mol H 2 for Ti 0.1 Zr 0.9 (Mn 0.9 V 0.1 ) 1.1 Fe 0.5 Ni 0.5 and 47.5 kJ/mol H 2 for Ti 0.1 Zr 0.9 Mn 0.9 V 0.1 Fe 0.55 Ni 0.55 , which are consistent with the proposed model in the literature [11,12]. It is well known that the smaller the activation energy, the larger the rate constant and the faster the reaction rate.…”

“…For an absorption process controlled by bulk diffusion in a spherical sample with radius (R), the reacted fraction (x) is obtained from the ratio x ¼ (P À P (t) )/(P À P N ), where P is the initial pressure of the reaction, P (t) and P N are the pressures at time t and final equilibrium, respectively [18]. Jander model and Chou model will be used below to analyze some experiment values from the literature [11,12].…”

“…The corresponding activation energies are 43.8 kJ/mol H 2 for Ti 0.1 Zr 0.9 (Mn 0.9 V 0.1 ) 1.1 Fe 0.5 Ni 0.5 and 48.5 kJ/mol H 2 for Ti 0.1 Zr 0.9 Mn 0.9 V 0.1 Fe 0.55 Ni 0.55 , which are close to those values evaluated by Jander diffusion model and consistent with the proposed model in Refs. [11,12].…”

“…In this paper, we will firstly obtain the experimental data from the literature [11,12] and use Jander model [13] and Chou model [14,15] to analyze the hydrogen absorption kinetic mechanism in the Zr-based AB 2 hydrogen storage alloys of Ti 0.1 Zr 0.9 Mn 0.9 V 0.1 Fe 0.5 Co 0.5 , Ti 0.1 Zr 0.9 (Mn 0.9 V 0.1 ) 1.1 Fe 0.5 Ni 0.5 and Ti 0.1 Zr 0.9 Mn 0.9 V 0.1 Fe 0.55 Ni 0.55 . Meanwhile, the model fitting method and the model predicting method in Zr-based AB 2 system will be compared and a more convenient and accurate method is presented to study the hydriding kinetic mechanism of AB 2 type hydrogen storage alloys.…”

Kinetics of hydrogen absorption in the solid solution region for Laves phase Ho1−xMmxCo2 (x=0, 0.2 and 0.4) alloys

“…Among these Laves alloys, the RT 2 (R ¼ rare earth elements, T ¼ 3d transition metal including Mn, Fe, Co, Ni and so on) alloys are especially attractive because they can easily absorb hydrogen up to a high capacity (the highest hydrogen storage capacity can reach upto 4.5 hydrogen atoms per formula unit) and form stable hydrides [1][2][3][4]. However, some inherent shortcomings of the Laves phase AB 2 -type alloys, especially in the kinetics, must be studied in order to promote their practical application.…”