Abstract
Hydrogen is a promising energy carrier as it can be produced through water electrolysis powered by renewable energy, and its combustion in fuel cell devices releases only water as a product. However, its efficient storage in gas or liquid form is energy inefficient due to the involved compression and cooling
stages. FeTi-based alloys offer an appealing solution to reversibly store large quantities of hydrogen compactly
under near ambient operating temperature and pressure conditions. However, due to the sensitivity of the
associated enthalpic properties to material composition, the hydrogenation properties of the resulting alloys may differ when FeTi is made from less pure raw and recycled materials. Understanding the effects of impurities is therefore crucial. In this context, computational thermodynamic modeling is an essential tool for leveraging the production,
design, and application of these materials. Yet, challenges arise when modeling multicomponent materials consisting of elements that have vastly different hydrogen affinities. To address this obstacle, this work presents a framework for modeling the thermodynamics of FeTi-based multicomponent hydrogen storage materials. Based on thermodynamic analysis and first-principles calculations, the proposed model enables the
description of hydrogenation properties under paraequilibrium — a specific state during the FeTi hydrogenation [1]. This work enhances the fundamental understanding of the composition-structure-properties relationships in multicomponent FeTi-based alloys for hydrogen storage, paving the way for
advanced computational simulations of their hydrogenation.
1 - Alvares et al. Calphad 77 102426 (2022).
