High-entropy hydrides for fast and reversible hydrogen storage at room temperature: Binding-energy engineering via first-principles calculations and experiments

Despite high interest in compact and safe storage of hydrogen in the solid-state hydride form, the de-sign of alloys that can reversibly and quickly store hydrogen at room temperature under pressures close to atmospheric pressure is a long-lasting challenge. In this study, first-principles calculations are com-bined with experiments to develop high-entropy alloys (HEAs) for room-temperature hydrogen storage. TixZr2-xCrMnFeNi (x = 0.4-1.6) alloys with the Laves phase structure and low hydrogen binding ener-gies of-0.1 to-0.15 eV are designed and synthesized. The HEAs reversibly store hydrogen in the form of Laves phase hydrides at room temperature, while (de)hydrogenation pressure systematically reduces with increasing the zirconium fraction in good agreement with the binding energy calculations. The ki-netics of hydrogenation are fast, the hydrogenation occurs without any activation or catalytic treatment, the hydrogen storage performance remains stable for at least 10 0 0 cycles, and the storage capacity is higher than that for commercial LaNi5. The current findings demonstrate that a combination of theoreti-cal calculations and experiments is a promising pathway to design new high-entropy hydrides with high performance for hydrogen storage.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study develops high-entropy alloys (HEAs) for room-temperature hydrogen storage through a combination of first-principles calculations and experiments. The HEAs can reversibly store hydrogen in the form of Laves phase hydrides at room temperature with fast hydrogenation kinetics and stable storage performance.