A novel high entropy spinel-type aluminate MAl₂O₄ (M = Zn, Mg, Cu, Co) and its lithiated oxyfluoride and oxychloride derivatives prepared by one-step mechanosynthesis

Abstract

For the first time, a spinel-type high entropy oxide (Zn0.25Cu0.25Mg0.25Co0.25)Al2O4 as well as its derivative lithiated high entropy oxyfluoride Li0.5(Zn0.25Cu0.25Mg0.25Co0.25)0.5Al2O3.5F0.5 and oxychloride Li0.5(Zn0.25Cu0.25Mg0.25Co0.25)0.5Al2O3.5Cl0.5 are prepared in the nanostructured state via high-energy co-milling of the simple oxide precursors and the halides (LiF or LiCl) as sources of lithium, fluorine and chlorine. Their nanostructure is investigated by XRD, HR-TEM, EDX and XPS spectroscopy. It is revealed that incorporation of lithium into the structure of spinel oxide together with the anionic substitution has significant effect on its short-range order, size and morphology of crystallites as well as on its oxidation/reduction processes. The charge capacity of the as-prepared nanomaterials tested by cyclic voltammetry is found to be rather poor despite lithiation of the samples in comparison to previously reported spinel-type high entropy oxides. Nevertheless, the present work offers the alternative one-step mechanochemical route to novel classes of high entropy oxides as well as to lithiated oxyfluorides and oxychlorides with the possibility to vary their cationic and anionic elemental composition.

Environmentally Benign pSOFC for Emissions-Free Energy: Assessment of Nickel Network Resistance in Anodic Ni/BCY15 Nanocatalyst

“…925 [31]. Higher BE values characterize oxygen vacancies (Ox-) registered at 529.9-531.1 eV [51][52][53][54]. Oxygen atomic concentration due to Me-Ox bonds was lower by 10% with Ni/BCY15-EG-1100, which indicates a lower degree of reoxidation.…”

High entropy nanomaterials for energy storage and catalysis applications

“…The fabrication of HEA nanoparticles (HEA-NPs) by carbothermal shock was described by Hu et al (2019), which sparked research on nanoscale high-entropy materials (HEMs). High-entropy oxides (HEOs), high-entropy nitrides (HENs), high-entropy borides (HEBs), high-entropy silicides (HESs), high-entropy metallic glasses (HEMGs), highentropy metal-organic frameworks (HE-MOFs), and other HEMs, which are now included in the broad definition of the "high entropy" concept, especially for energy storage applications (Hussain et al, 2021;Porodko et al, 2022). High entropy nanomaterials have chemical and physical properties that enable superior catalytic performances.…”

High-entropy oxychloride increasing the stability of Li–sulfur batteries

“…1.5 V vs. Li + / Li, which is outside the usual electrochemical window of Li-S batteries. 22,26,28 Instead, they can, presumably, serve as efficient PS adsorbents due to the presence of oxygen vacancies in their structure. Our recent studies conrmed the benecial effect of various inorganic additives on the capacity and cycling stability of the composite cathode in Li-sulfur batteries.…”

“…Recently, we studied the mechanochemical synthesis of the novel spinel-type high-entropy oxide (aluminate) and its lithiated derivatives-oxychloride and oxyfluoride. 26 Although these materials have not yet been optimized from the point of view of their electrochemical properties, they can hardly contribute by their inherent electrochemical activity to the redox processes taking place in Li–sulfur batteries analogously to TiO 2 , 27 because their redox activity occurs at potentials smaller than ca. 1.5 V vs. Li + /Li, which is outside the usual electrochemical window of Li–S batteries.…”