Lithium containing layered high entropy oxide structures

Abstract Layered Delafossite-type Lix(M1M2M3M4M5…Mn)O2 materials, a new class of high-entropy oxides, were synthesized by nebulized spray pyrolysis and subsequent high-temperature annealing. Various metal species (M = Ni, Co, Mn, Al, Fe, Zn, Cr, Ti, Zr, Cu) could be incorporated into this structure type, and in most cases, single-phase oxides were obtained. Delafossite structures are well known and the related materials are used in different fields of application, especially in electrochemical energy storage (e.g., LiNixCoyMnzO2 [NCM]). The transfer of the high-entropy concept to this type of materials and the successful structural replication enabled the preparation of novel compounds with unprecedented properties. Here, we report on the characterization of a series of Delafossite-type high-entropy oxides by means of TEM, SEM, XPS, ICP-OES, Mössbauer spectroscopy, XRD including Rietveld refinement analysis, SAED and STEM mapping and discuss about the role of entropy stabilization. Our experimental data indicate the formation of uniform solid-solution structures with some Li/M mixing.

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Layered High-Entropy Oxide Structures for Reversible Energy Storage

10.26434/chemrxiv.11778390.v1 ◽

2020 ◽

Author(s):

Junbo Wang ◽

Yanyan Cui ◽

Qingsong Wang ◽

Kai Wang ◽

Xiaohui Wang ◽

...

Keyword(s):

Energy Storage ◽

Cathode Material ◽

Spray Pyrolysis ◽

Lattice Structure ◽

Oxide Materials ◽

High Entropy ◽

New Class ◽

Nebulized Spray Pyrolysis

Layered LixMO2 materials, a new class of high-entropy oxides, have been synthesized by nebulized spray pyrolysis. Specifically, the lattice structure of Li(Ni1/3Mn1/3Co1/3)O2 (NCM111) cathode material has been replicated successfully while increasing the number of cations in equimolar proportions, thereby allowing transition to high-entropy oxide materials.

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Fabrication and Characterization of Quinary High Entropy-Ultra-High Temperature Diborides

Ceramics ◽

10.3390/ceramics4020010 ◽

2021 ◽

Vol 4 (2) ◽

pp. 108-120

Author(s):

Simone Barbarossa ◽

Roberto Orrù ◽

Valeria Cannillo ◽

Antonio Iacomini ◽

Sebastiano Garroni ◽

...

Keyword(s):

High Temperature ◽

Single Phase ◽

Nominal Composition ◽

High Entropy ◽

Chemical Complexity ◽

Alternative Processing ◽

Plasma Sintering ◽

High Temperature Synthesis ◽

Spark Plasma

Due to their inherent chemical complexity and their refractory nature, the obtainment of highly dense and single-phase high entropy (HE) diborides represents a very hard target to achieve. In this framework, homogeneous (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2, (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2, and (Hf0.2Zr0.2Nb0.2Mo0.2Ti0.2)B2 ceramics with high relative densities (97.4, 96.5, and 98.2%, respectively) were successfully produced by spark plasma sintering (SPS) using powders prepared by self-propagating high-temperature synthesis (SHS). Although the latter technique did not lead to the complete conversion of initial precursors into the prescribed HE phases, such a goal was fully reached after SPS (1950 °C/20 min/20 MPa). The three HE products showed similar and, in some cases, even better mechanical properties compared to ceramics with the same nominal composition attained using alternative processing methods. Superior Vickers hardness and elastic modulus values were found for the (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2 and the (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2 systems, i.e., 28.1 GPa/538.5 GPa and 28.08 GPa/498.1 GPa, respectively, in spite of the correspondingly higher residual porosities (1.2 and 2.2 vol.%, respectively). In contrast, the third ceramic, not containing tantalum, displayed lower values of these two properties (25.1 GPa/404.5 GPa). However, the corresponding fracture toughness (8.84 MPa m1/2) was relatively higher. This fact can be likely ascribed to the smaller residual porosity (0.3 vol.%) of the sintered material.

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Role of size, alio-/multi-valency and non-stoichiometry in the synthesis of phase-pure high entropy oxide (Co,Cu,Mg,Na,Ni,Zn)O

Dalton Transactions ◽

10.1039/d0dt00958j ◽

2020 ◽

Vol 49 (21) ◽

pp. 7123-7132 ◽

Cited By ~ 1

Author(s):

Nandhini J. Usharani ◽

Rajat Shringi ◽

Harshil Sanghavi ◽

S. Subramanian ◽

S. S. Bhattacharya

Keyword(s):

Phase Formation ◽

Single Phase ◽

High Entropy ◽

Phase Pure ◽

Single Phase Formation

Presence of multivalency/non-stoichiometry to accommodate a different-sized cation and maintaining electroneutrality were identified as the critical criteria for single-phase formation in multicomponent/high entropy systems.

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Synthesis and characterization of a new class of single-phase AlVO4 precursors

Materials Research Innovations ◽

10.1080/14328917.2016.1198459 ◽

2016 ◽

Vol 21 (3) ◽

pp. 172-176 ◽

Cited By ~ 1

Author(s):

Mukesh Kumar Atal ◽

Ajay Saini ◽

Ram Gopal ◽

Meena Nagar ◽

Veena Dhayal

Keyword(s):

Single Phase ◽

Synthesis And Characterization ◽

New Class

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Reaction synthesis and characterization of a new class high entropy carbide (NbTaMoW)C

Materials Science and Engineering A ◽

10.1016/j.msea.2020.140520 ◽

2020 ◽

pp. 140520 ◽

Cited By ~ 1

Author(s):

Diqiang Liu ◽

Aijun Zhang ◽

Jiangang Jia ◽

Junyan Zhang ◽

Junhu Meng

Keyword(s):

Synthesis And Characterization ◽

Reaction Synthesis ◽

High Entropy ◽

New Class

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Hyphenated HPLC/ICP-MS and HPLC/ICP-OES techniques for the characterization of metal and non-metal species

Fresenius Journal of Analytical Chemistry ◽

10.1007/bf00323108 ◽

1994 ◽

Vol 349 (12) ◽

pp. 794-799 ◽

Cited By ~ 12

Author(s):

J�rg Sch�ppenthau ◽

Lothar Dunemann

Keyword(s):

Metal Species ◽

Icp Oes ◽

Icp Ms

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A chloroquine-resistant Swiss 3T3 cell line with a defect in late endocytic acidification

The Journal of Cell Biology ◽

10.1083/jcb.106.2.269 ◽

1988 ◽

Vol 106 (2) ◽

pp. 269-277 ◽

Cited By ~ 29

Author(s):

CC Cain ◽

RF Murphy

Keyword(s):

Acridine Orange ◽

Cell Line ◽

Second Phase ◽

Lysosomal Fraction ◽

New Class ◽

Swiss 3T3 Cell

To investigate the role of acidification in cell proliferation, several cell lines resistant to chloroquine were isolated with the expectation that some would express altered endocytic acidification. The preliminary characterization of one of these lines, CHL60-64, is described. In contrast to endocytic mutants described previously, the initial phase of endocytic acidification, as measured by transferrin acidification, is normal in this cell line. However, a difference in subsequent endocytic acidification was observed in CHL60-64. In the parental cells, internalized dextran was fully acidified to approximately pH 5.5 within 1 h. In CHL60-64, the pH in the endocytic compartment was only 6.1 after 1 h and remained as high as 5.8 for at least 4 h. After an 8-h incubation, the pH decreased to 5.5, indicating that the second phase of acidification is only slowed in CHL60-64, and not blocked. Consistent with this retarded acidification, ATP-dependent acidification in vitro (as measured by acridine orange accumulation) was reduced in both the lysosomal fraction and the endosomal fraction isolated from CHL60-64. A decrease in the in vivo rate of acridine orange accumulation after perturbation with amine was also observed. In addition to amine resistance and defective acidification, CHL60-64 was found to be resistant to vacuolation in the presence of chloroquine and ammonium chloride, and was resistant to ouabain. Further studies on this new class of endocytosis mutant, in combination with existing mutants, should help to clarify the mechanisms responsible for the regulation of endocytic acidification.

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Layered High-Entropy Oxide Structures for Reversible Energy Storage

10.26434/chemrxiv.11778390 ◽

2020 ◽

Author(s):

Junbo Wang ◽

Yanyan Cui ◽

Qingsong Wang ◽

Kai Wang ◽

Xiaohui Wang ◽

...

Keyword(s):

Energy Storage ◽

Cathode Material ◽

Spray Pyrolysis ◽

Lattice Structure ◽

Oxide Materials ◽

High Entropy ◽

New Class ◽

Nebulized Spray Pyrolysis

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High-entropy alloys in light transition metal systems

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314090561 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C943-C943

Author(s):

Roksolana Kozak ◽

Walter Steurer

Keyword(s):

Single Phase ◽

Elevated Temperatures ◽

High Hardness ◽

High Entropy Alloys ◽

X Ray Diffraction ◽

High Entropy ◽

Mixing Entropy ◽

Al Content ◽

New Class ◽

Arc Melting

High-entropy alloys (HEAs) are a new class of alloys designed with the approach of maximization of configurational mixing entropy by increasing the number of constituents [1,2]. Alloys produced in such a way are reported for a variety of promising properties (high hardness and strength, wear resistance, magnetism etc.) [3]. However, origin of these properties (microstructure, phase content, element composition, thermal history) is not always clear. High mixing entropy in HEAs favours the formation of single-phase substitutional solid solutions at elevated temperatures with approximately equiatomic compositions and simple average crystal structures of either the cF4-Cu (fcc) or the cI2-W (bcc). Nevertheless, only a few element combinations produce truly single-phase materials. In order to search for new HEAs compositions samples in the systems Cr-Fe-Co-Ni-Al and Cr-Fe-Co-Ni-Mn were synthesized by arc melting and homogenized in tantalum ampoules at 1100 and 1300 °C for 2 weeks. DTA, X-ray diffraction and electron microscopy measurements were performed. Only samples with small Al content (~ 5 at.%) showed the single-phase microstructure. Their local atomic structure is under investigation.

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Is Configurational Entropy the Main Stabilizing Term in Rock-Salt Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O High-Entropy Oxide?

10.26434/chemrxiv.14464980 ◽

2021 ◽

Author(s):

Martina Fracchia ◽

Mauro Coduri ◽

Maela Manzoli ◽

Paolo Ghigna ◽

Umberto Anselmi-Tamburini

Keyword(s):

Solid Solution ◽

Rock Salt ◽

Single Phase ◽

Configurational Entropy ◽

Rock Salt Structure ◽

High Entropy ◽

Reversible Transformation ◽

Salt Structure ◽

Cubic Structure

We question the conclusions reported in the paper "Entropy-stabilized Oxides, by C. Rost et al., by looking into the role of configurational entropy as the stabilization of the rock-salt cubic structure of the Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O (HEO) solid solution (SS). First, we demonstrate that configurational entropy can be reduced from 1.61R for HEO to 0.5R for a two-member SS, still obtaining a single-phase material if the molar fractions of ZnO and CuO are 0.2. These SSs behave identically as HEO regarding the reversible transformation between a multi- and single-phase states when temperatures are cycled between 800 and 1000 °C. Second, we demonstrate that the different SSs presenting a configurational entropy significantly lower than HEO, are less prone to the cubic to tetragonal structural distortion, suggesting that the configurational entropy has not the central role as stabilizing factor of the rock-salt structure.

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