Spinel-type high-entropy (Co0.2Mn0.2Fe0.2Zn0.2Ti0.2)3O4 oxides constructed from disordered cations and oxygen vacancies

2021 ◽  
pp. 163188
Author(s):  
Bing Wang ◽  
Jincheng Yao ◽  
Junhua Wang ◽  
Aimin Chang
Keyword(s):  
Oxygen Vacancies ◽  
Spinel Type ◽  
High Entropy

Porous spinel-type (Al0.2CoCrFeMnNi)0.58O4-δ high-entropy oxide as a novel high-performance anode material for lithium-ion batteries

2021 ◽  
Vol 56 (13) ◽  
pp. 8127-8142
Author(s):  
Hou-Zheng Xiang ◽  
Hong-Xiang Xie ◽  
Yu-Xue Chen ◽  
Hui Zhang ◽  
Aiqin Mao ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Anode Material ◽  
High Performance ◽  
Lithium Ion ◽  
Spinel Type ◽  
High Entropy

scholarly journals Spinel-Type (FeCoCrMnZn)3O4 High-Entropy Oxide: Facile Preparation and Supercapacitor Performance

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5798
Author(s):  
Bingliang Liang ◽  
Yunlong Ai ◽  
Yiliang Wang ◽  
Changhong Liu ◽  
Sheng Ouyang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Nickel Foam ◽  
Spinel Type ◽  
X Ray ◽  
High Entropy ◽  
Transmission Electron ◽  
Coating Method ◽  
Potential Applications ◽  
Supercapacitor Performance

High-entropy oxides (HEOs) have attracted more and more attention because of their unique structures and potential applications. In this work, (FeCoCrMnZn)3O4 HEO powders were synthesized via a facile solid-state reaction route. The confirmation of phase composition, the observation of microstructure, and the analysis of crystal structure, distribution of elements, and valences of elements were conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS), respectively. Furthermore, a (FeCoCrMnZn)3O4/nickel foam ((FeCoCrMnZn)3O4/NF) electrode was prepared via a coating method, followed by the investigation of its supercapacitor performance. The results show that, after calcining (FeCoCrMnZn)3O4 powders at 900 °C for 2 h, a single spinel structure (FCC, Fd-3m, a = 0.8399 nm) was obtained with uniform distribution of Fe, Co, Cr, Mn, and Zn elements, the typical characteristic of a high-entropy oxide. In addition, the mass specific capacitance of the (FeCoCrMnZn)3O4/NF composite electrode was 340.3 F·g−1 (with 1 M KOH as the electrolyte and 1 A·g−1 current density), which indicates that the (FeCoCrMnZn)3O4 HEO can be regarded as a prospective candidate for an electrode material in the field of supercapacitor applications.

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

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Olena Porodko ◽  
Martin Fabián ◽  
Hristo Kolev ◽  
Maksym Lisnichuk ◽  
Markéta Zukalová ◽  
...  
Keyword(s):  
High Energy ◽  
Spinel Oxide ◽  
Spinel Type ◽  
High Entropy ◽  
Reduction Processes ◽  
Simple Oxide ◽  
Oxidation Reduction ◽  
One Step ◽  
Size And Morphology ◽  
First Time

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.

scholarly journals High Temperature Oxidation Behavior of an Equimolar Cr-Mn-Fe-Co High-Entropy Alloy

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4259
Author(s):  
Lin Wang ◽  
Quanqing Zeng ◽  
Zhibao Xie ◽  
Yun Zhang ◽  
Haitao Gao
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
High Entropy Alloy ◽  
Spinel Type ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
High Entropy ◽  
High Temperature Oxidation Behavior

The oxidation behavior of an equimolar Cr-Mn-Fe-Co high-entropy alloy (HEA) processed by 3D laser printing was investigated at 700 °C and 900 °C. The oxidation kinetics of the alloy followed the parabolic rate law, and the oxidation rate constant increased with the rising of the temperature. Inward diffusion of oxygen and outward diffusion of cations took place during the high-temperature oxidation process. A spinel-type oxide was formed on the surface, and the thickness of the oxide layer increased with the rising of experimental temperature or time. The exfoliation of the oxide layer took place when the test was operated at 900 °C over 12 h. During oxidation tests, the matrix was propped open by oxides and was segmented into small pieces. The formation of loose structures had great effects on the high-temperature oxidation resistance of the HEA.

Spinel-type NiCo2O4 with abundant oxygen vacancies as a high-performance catalyst for the oxygen reduction reaction

2019 ◽  
Vol 44 (42) ◽  
pp. 23775-23783 ◽  
Author(s):  
Dongwook Lim ◽  
Hyungseok Kong ◽  
Chaewon Lim ◽  
Namil Kim ◽  
Sang Eun Shim ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
High Performance ◽  
Oxygen Vacancies ◽  
Reduction Reaction ◽  
Spinel Type

Engineering the Oxygen Vacancies of Rocksalt Type High-entropy Oxides for Enhanced Electrocatalysis

Nanoscale ◽  
2021 ◽  
Author(s):  
Yaohang Gu ◽  
Ateer Bao ◽  
Xuanyu Wang ◽  
Yi-Zhen Chen ◽  
Liang Dong ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
High Entropy

High-entropy oxides (HEOs), a class of compounds that include five or more elemental species, have gained increasing attractions for the capability of optimizing target properties. To date, even though some...

Conditions for atomic imaging of mullite

1989 ◽  
Vol 47 ◽  
pp. 418-419
Author(s):  
T. A. Epicier ◽  
G. Thomas
Keyword(s):  
Oxygen Vacancies ◽  
High Resolution Electron Microscopy ◽  
Ceramic Materials ◽  
Work Conditions ◽  
Real Space ◽  
Potential Candidate ◽  
Silicate Mineral ◽  
Resolution Electron ◽  
The Subject ◽  
Aluminium Silicate

Mullite is an aluminium-silicate mineral of current interest since it is a potential candidate for high temperature applications in the ceramic materials field.In the present work, conditions under which the structure of mullite can be optimally imaged by means of High Resolution Electron Microscopy (HREM) have been investigated. Special reference is made to the Atomic Resolution Microscope at Berkeley which allows real space information up to ≈ 0.17 nm to be directly transferred; numerous multislice calculations (conducted with the CEMPAS programs) as well as extensive experimental through-focus series taken from a commercial “3:2” mullite at 800 kV clearly show that a resolution of at least 0.19 nm is required if one wants to get a straightforward confirmation of atomic models of mullite, which is known to undergo non-stoichiometry associated with the presence of oxygen vacancies.Indeed the composition of mullite ranges from approximatively 3Al2O3-2SiO2 (referred here as 3:2-mullite) to 2Al2O3-1SiO2, and its structure is still the subject of refinements (see, for example, refs. 4, 5, 6).

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