Multi-principal-element Alloys as Solid Stores for HYdrogen – MASSHY

The alloys were synthesized by the arc fusion method with the exception of the Mg-containing alloys which were obtained by high-energy grinding under Argon. This last synthetic route is suitable for the preparation of alloys containing Mg which has a very low melting point compared to refractory metals and above all, a very high vapour pressure.
Their hydrogen sorption properties (absorption capacity and kinetics at room temperature, absorption / desorption cycling, phase stability during cycling, etc.) will be determined.

First, we performed the synthesis and characterization of Ti0.30V0.25Zr0.10Nb0.25X0.10 alloys with X = Mg, Al, Cr, Mn, Mo and Ta. The goal is to understand the effect of the addition of element X on the H2 storage performance of the initial quaternary alloy Ti0.325V0.275Zr0.120Nb0.275. This quaternary composition serves as a reference for a comparison of the physicochemical and hydrogen sorption properties and has already been the subject of our previous research published in J. Montero et al. Molecules 24 (2019) 2799.
The alloys obtained are single-phase and adopt a centred cubic structure. Their hydrogen sorption properties are under study.

The progress did not follow the initial plan because of the pandemic situation in 2020 and 2021. We will continue the work according to the established plan but with significant delays.

3 articles were published in peer-review international journals:

1. J. Montero, G. Ek, L. Laversenne, V. Nassif, G. Zepon, M. Sahlberg, C. Zlotea, Hydrogen storage properties of the refractory TiVZrNbTa multi-principal element alloy, Journal of Alloys and Compounds 835 (2020) 155376

2. J. Montero, G. Ek, L. Laversenne, V. Nassif, M. Sahlberg, C. Zlotea, How 10 at% Al addition in the Ti-V-Zr-Nb high entropy alloy changes hydrogen sorption properties, Molecules 26 (2021) 2470

3. J. Montero, G. Ek, M. Sahlberg, C. Zlotea, Improving the hydrogen cycling properties by Mg addition in Ti-V-Zr-Nb refractory high entropy alloy, Scripta Materialia 194 (2021) 113699

MASSHY project (Multi-principal-element Alloys as Solid Stores for HYdrogen) proposes to develop Multi-Principal-Element Alloys as novel hydrogen storage materials with high-hydrogen density, capacities and good reversibility. These materials belong to a new metallurgical paradigm based on the alloying of four or more elements with equal concentrations. Most of reports concerning these alloys describe their structure, microstructure and mechanical properties, whereas functional properties such as, hydrogen storage, are only scarcely investigated. In this context, the study of hydrogen storage properties of these alloys is an original research topic that might open new routes for the design of multifunctional materials. To ensure the success of the project, we propose a collaboration between two French CNRS laboratories, Institut de Chimie et des Matériaux Paris-Est and Institut Néel together with a Swedish team from the Ångström Laboratory.