STRESS EFFECTS ON THE KINETICS OF HYDRIDE FORMATION AND GROWTH IN METALS

Abstract

ALTHOUGH METAL HYDRIDES ARE CONSIDERED PROMISING CANDIDATES FOR SOLID-STATE HYDROGEN STORAGE, THEIR USE FOR PRACTICAL APPLICATIONS REMAINS A CHALLENGE DUE TO THE LIMITATION IMPOSED BY THE SLOW KINET-ICS OF HYDROGEN UPTAKE AND RELEASE. THIS HAS DRIVEN THE INTEREST IN USING METAL NANOPARTICLES AS ADVANCED MATERIALS OF NEW HYDROGEN-STORAGE SYSTEMS SINCE THEY DISPLAY FAST HYDROGENATION AND DEHYDRO-GENATION KINETICS. NEVERTHELESS, THE UNDERSTANDING OF THE ADSORP-TION/RELEASE KINETICS REQUIRES THE INVESTIGATION OF THE ROLE PLAYED BY THE STRESS WHICH APPEARS TO ACCOMMODATE THE MISFIT BETWEEN THE METAL AND HYDRIDE PHASES. IN THIS PAPER, WE PRESENT A CONTINUUM THEORY CAPABLE OF ASSESSING HOW THE MISFIT STRESS AFFECTS THE KINETICS OF HYDRIDE FORMATION AND GROWTH IN METALLIC NANOPARTICLES. THE THEORY IS THEN APPLIED TO STUDY THE KINETICS OF ADSORPTION/RELEASE IN SPHERICAL PARTICLES. THIS WORK EXTENDS DUDA AND TOMASSETTI (2015, 2016) BY CONSIDERING STRESS-DEPENDENT HYDROGEN MOBILITY