Developing novel protocols for hydrogen (H) loading is crucial for furthering the investigation of hydrides as potential high-temperature superconductors at lower pressures compared to recent discoveries. Ionic gating-induced protonation (IGP) has emerged as a promising technique for H loading due to its inherent simplicity, but it can be limited in the maximum density of injected H when ionic liquids are used as a gating medium. Additionally, most ionic liquids are limited by high production costs, complex synthesis, and potential toxicity. Here, we demonstrate that large H concentrations can be successfully injected in both palladium (Pd) bulk foils and thin films (up to a stoichiometry PdH0.89) by using a deep eutectic solvent (DES) choline chloride:glycerol 1:3 as gate electrolyte and applying gate voltages in excess of the cathodic stability limit. The attained H concentrations are large enough to induce superconductivity in Pd, albeit with an incomplete resistive transition which suggests a strongly inhomogeneous H incorporation in the Pd matrix. This DES-based IGP protocol can be used as a guideline for maximizing H loading in different materials, although specific details of the applied voltage profile might require adjustments based on the material under investigation.

Facile synthesis of palladium hydride via ionic gate-driven protonation using a deep eutectic solvent / Gavello, Gaia; Tofani, Giorgio; DE FAZIO, Domenico; Lettieri, Stefania; Mezzetta, Andrea; Guazzelli, Lorenzo; Pomelli, Christian S.; Gonnelli, Renato S.; Piatti, Erik; Daghero, Dario. - In: JOURNAL OF MOLECULAR LIQUIDS. - ISSN 0167-7322. - STAMPA. - 420:(2025). [10.1016/j.molliq.2024.126826]

Facile synthesis of palladium hydride via ionic gate-driven protonation using a deep eutectic solvent

Gaia Gavello;Domenico De Fazio;Stefania Lettieri;Renato S. Gonnelli;Erik Piatti;Dario Daghero
2025

Abstract

Developing novel protocols for hydrogen (H) loading is crucial for furthering the investigation of hydrides as potential high-temperature superconductors at lower pressures compared to recent discoveries. Ionic gating-induced protonation (IGP) has emerged as a promising technique for H loading due to its inherent simplicity, but it can be limited in the maximum density of injected H when ionic liquids are used as a gating medium. Additionally, most ionic liquids are limited by high production costs, complex synthesis, and potential toxicity. Here, we demonstrate that large H concentrations can be successfully injected in both palladium (Pd) bulk foils and thin films (up to a stoichiometry PdH0.89) by using a deep eutectic solvent (DES) choline chloride:glycerol 1:3 as gate electrolyte and applying gate voltages in excess of the cathodic stability limit. The attained H concentrations are large enough to induce superconductivity in Pd, albeit with an incomplete resistive transition which suggests a strongly inhomogeneous H incorporation in the Pd matrix. This DES-based IGP protocol can be used as a guideline for maximizing H loading in different materials, although specific details of the applied voltage profile might require adjustments based on the material under investigation.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2996412