Entropy-Stabilized Oxides owning Fluorite Structure obtained by Hydrothermal Treatment

Abstract

Entropy-Stabilized Oxides (ESO) is a modern class of multicomponent advanced ceramic materials with attractive functional properties. Through a five-component oxide formulation, the configurational entropy is used to drive the phase stabilization over a reversible solid-state transformation from a multiphase to a single-phase state. In this paper, a new transition metal/rare earth entropy-stabilized oxide, with composition Ce0.2Zr0.2Y0.2Gd0.2La0.2O2−δ, was found after several investigations on alternative candidate systems. X-Ray Diffraction (XRD) analyses of calcined powders pointed out different behavior as a function of the composition and a single-phase fluorite structure was obtained after a specific thermal treatment at 1500 °C. Powders presented the absence of agglomeration, so that the sintered specimen exhibited sufficient densification with a small porosity, uniformly distributed in the sample.

Magnetic properties of high entropy oxides

“…The growing interest in the field of HEOs is illustrated by the numerous studies focusing on their different structural and functional aspects that have already been reported within the five years since their discovery. Currently, there are eight major classes of HEOs that can be categorized based on the crystallographic structures: rocksalt, 1,3,8,9 fluorite, [10][11][12][13][14][15] bixbyite, 10,12,16 perovskite (cubic, orthorhombic, rhombohedral), 5,[17][18][19] spinel, 20,21 pyrochlore, 7,[22][23][24] layered (Ruddlesden-Popper and delafossite) [25][26][27] and magnetoplumbite. 28,29 Likewise, a broad range of properties, such as electrochemical, 2,[30][31][32] optical, 11,[33][34][35] magnetic, 21,29,34,[36][37][38][39][40][41][42]…”

In Situ High Pressure Structural Investigation of Sm-Doped Ceria

“…Together with Gd-and Nd-doped ceria, Sm-doped ceria is one of the most effective systems of ionic conductivity [1]. Ionic conductivity is strictly related to structural and microstructural issues, and this is the reason why so many papers in recent years have been devoted to the crystallographic properties of this material, even in the light of the non-negligible effects of extrinsic factors (e.g., thermal treatments) on the stability of the various oxide phases [15,16]. A particular attention has been paid to defect aggregations [3,[17][18][19][20][21], since ionic conductivity in doped ceria occurs through the hopping of oxygen ions towards the vacancies (V .. O ) created for charge compensation when Ce 4+ is partially substituted by RE 3+ .…”

High-Rate Layered Cathode of Lithium-Ion Batteries through Regulating Three-Dimensional Agglomerated Structure

“…It has been previously reported that urea can be used as a precipitator in hydrothermal treatment to construct samples of different morphologies [31][32][33][34]. In this work, three-dimensional agglomerated structures from unclosed to blocking sphere-shaped microstructure for NCM 111 were designed by controlling the contents of urea to get excellent electrochemical performance.…”