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Data-Driven Discovery and Synthesis of High Entropy Alloy Hydrides with Targeted Thermodynamic Stability

Witman, Matthew; Ek, Gustav; Ling, Sanliang; Chames, Jeffery; Agarwal, Sapan; Wong, Justin; Allendorf, Mark D.; Sahlberg, Martin; Stavila, Vitalie


Matthew Witman

Gustav Ek

Jeffery Chames

Sapan Agarwal

Justin Wong

Mark D. Allendorf

Martin Sahlberg

Vitalie Stavila


Solid-state hydrogen storage materials that are optimized for specific use cases could be a crucial facilitator of the hydrogen economy transition. Yet, the discovery of novel hydriding materials has historically been a manual process driven by chemical intuition or experimental trial and error. Data-driven materials’ discovery paradigms provide an alternative to traditional approaches, whereby machine/statistical learning (ML) models are used to efficiently screen materials for desired properties and significantly narrow the scope of expensive/time-consuming first-principles modeling and experimental validation. Here, we specifically focus on a relatively new class of hydrogen storage materials, high entropy alloy (HEA) hydrides, whose vast combinatorial composition space and local structural disorder necessitate a data-driven approach that does not rely on exact crystal structures to make property predictions. Our ML model quickly screens hydride stability within a large HEA space and permits down selection for laboratory validation based on not only targeted thermodynamic properties but also secondary criteria such as alloy phase stability and density. To experimentally verify our predictions, we performed targeted synthesis and characterization of several novel hydrides that demonstrate significant destabilization (70× increase in equilibrium pressure, 20 kJ/molH2 decrease in desorption enthalpy) relative to the benchmark HEA hydride, TiVZrNbHfHx. Ultimately, by providing a large composition space in which hydride thermodynamics can be continuously tuned over a wide range, this work will enable efficient material selection for various applications, especially in areas such as metal hydride-based hydrogen compressors, actuators, and heat pumps.


Witman, M., Ek, G., Ling, S., Chames, J., Agarwal, S., Wong, J., …Stavila, V. (2021). Data-Driven Discovery and Synthesis of High Entropy Alloy Hydrides with Targeted Thermodynamic Stability. Chemistry of Materials, 33(11), 4067–4076.

Journal Article Type Article
Acceptance Date Apr 19, 2021
Online Publication Date Apr 28, 2021
Publication Date Jun 8, 2021
Deposit Date May 1, 2021
Publicly Available Date Apr 29, 2022
Journal Chemistry of Materials
Print ISSN 0897-4756
Electronic ISSN 1520-5002
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 33
Issue 11
Pages 4067–4076
Keywords Materials Chemistry; General Chemistry; General Chemical Engineering
Public URL
Publisher URL
Additional Information This document is the Accepted Manuscript version of a Published Work that appeared in final form in Chemistry of Materials,copyright© American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see


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