Alexander Missyul | ALBA CELLS (original) (raw)

Papers by Alexander Missyul

Materials horizons, 2021

Mixed-valent transition-metal compounds display complex structural, electronic and magnetic prope... more Mixed-valent transition-metal compounds display complex structural, electronic and magnetic properties, which often intricately coexist. Here, we report the new ternary oxide GaV4O8, a structural sibling of skyrmion-hosting lacunar spinels. GaV4O8 contains a vanadium trimer and an original spin-orbital-charge texture that forms upon the structural phase transition at TS = 68 K followed by the magnetic transition at TN = 35 K. The texture arises from the coexistence of orbital molecules on the vanadium trimers and localized electrons on the remaining vanadium atoms. Such hybrid electrons create opportunities for novel types of spin, charge, and orbital order in mixed-valent transition-metal compounds.

Glass Physics and Chemistry, Apr 1, 2010

The possibility of the substitution Bi Ln occurring in the Bi 3 TaTiO 9 Aurivillius phases has be... more The possibility of the substitution Bi Ln occurring in the Bi 3 TaTiO 9 Aurivillius phases has been studied for the first time. The Bi 2 LaTaTiO 9 , Bi 2 NdTaTiO 9 , Bi 2 SmTaTiO 9 , and Bi 2 GdTaTiO 9 compounds have been synthesized according to solid phase reactions in the temperature range 800-1100°C, and their unit cell parameters have been determined.

Materials Research Bulletin, Dec 1, 2012

ChemInform, May 12, 2011

Process of Formation of the Aurivillius Phase Bi 3 NbTiO 9 and Its Substitutes.-Two series of mag... more Process of Formation of the Aurivillius Phase Bi 3 NbTiO 9 and Its Substitutes.-Two series of magnetically substituted Aurivillius phases which could potentially show both ferroelectricity and magnetic ordering, Bi3NbTi1-xMnxO9 (x = 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1) and Bi2LnNbTiO9 (Ln: Nd-Ho), are prepared from stoichiometric mixtures of Bi2O3, TiO2, Nb2O5, MnO2, and Ln2O3 (800-1100°C, 3-5 h). The substitution is limited in both series. Bi 3 NbTi 1-x Mn x O 9 exhibits the pure Aurivillius phase for x = 0.1 and x = 0.2, whereas for x ≥ 0.3 the pyrochlore phase appears. Bi2LnNbTiO9 exhibits pure Aurivillius phases for Ln: Nd-Gd. The kinetics of Bi3NbTiO9 formation from the binary oxides are studied and a formation mechanism is proposed.-(MISSYUL*,

Separation and Purification Technology, Oct 1, 2018

Novel mixed-matrix membranes based on polyvinyl alcohol and its composites with carboxyfullerene ... more Novel mixed-matrix membranes based on polyvinyl alcohol and its composites with carboxyfullerene were developed. Carboxyfullerene was simultaneously used as a modifier and a cross-linker for polyvinyl alcohol. The structural properties of the developed composites were studied by nuclear magnetic resonance, X-ray diffraction analysis, scanning electron microscopy, and sorption experiments. Thermal properties and stability were investigated by thermogravimetric analysis and differential scanning calorimetry. Surface features were studied by measuring the contact angles by water. The transport properties of the developed membranes were studied in ethanol-water mixtures separation by pervaporation (4.4-90 wt.% water in the feed) at different temperatures (22, 35, 50°C). All membranes were selective with respect to water. The optimal transport properties were obtained for the PVA-carboxyfullerene (3.5 wt.%) membranes containing catalyst p-toluenesulfonic acid.

Small, Jul 2, 2023

Herein, the electrochemical properties and reaction mechanism of Li3‒2xCaxV2(PO4)3/C (x = 0, 0.5,... more Herein, the electrochemical properties and reaction mechanism of Li3‒2xCaxV2(PO4)3/C (x = 0, 0.5, 1, and 1.5) as negative electrode materials for sodium‐ion/potassium‐ion batteries (SIBs/PIBs) are investigated. All samples undergo a mixed contribution of diffusion‐controlled and pseudocapacitive‐type processes in SIBs and PIBs via Trasatti Differentiation Method, while the latter increases with Ca content increase. Among them, Li3V2(PO4)3/C exhibits the highest reversible capacity in SIBs and PIBs, while Ca1.5V2(PO4)3/C shows the best rate performance with a capacity retention of 46% at 20 C in SIBs and 47% at 10 C in PIBs. This study demonstrates that the specific capacity of this type of material in SIBs and PIBs does not increase with the Ca‐content as previously observed in lithium‐ion system, but the stability and performance at a high C‐rate can be improved by replacing Li+ with Ca2+. This indicates that the insertion of different monovalent cations (Na+/K+) can strongly influence the redox reaction and structure evolution of the host materials, due to the larger ion size of Na+ and K+ and their different kinetic properties with respect to Li+. Furthermore, the working mechanism of both LVP/C and Ca1.5V2(PO4)3/C in SIBs are elucidated via in operando synchrotron diffraction and in operando X‐ray absorption spectroscopy.

Glass Physics and Chemistry, Nov 1, 2003

The processes of phase formation in the Nd 2 O 3-Ho 2 O 3-SrO-Al 2 O 3 system are investigated in... more The processes of phase formation in the Nd 2 O 3-Ho 2 O 3-SrO-Al 2 O 3 system are investigated in the temperature range 1100-1530 ° C. It is revealed that the structural-chemical mechanism of formation of (Nd x Ho 1-x) 2 SrAl 2 O 7 solid solutions depends on the temperature and composition. An increase in the holmium content and in the temperature leads to a crossover from the mechanism including the formation of LnAlO 3 and LnSrAlO 4 as intermediate products to the mechanism in which the interaction of Ln 2 O 3 and SrAl 2 O 4 is a limiting stage.

Chemistry of Materials, May 27, 2020

The discovery of Li-containing transition-metal (TM) oxides has attracted broad interest and trig... more The discovery of Li-containing transition-metal (TM) oxides has attracted broad interest and triggered intensive studies on these oxides as cathodes for lithium-ion batteries over decades. Unfortunately, a clear picture of how Li/TM/O ions are transported and electrons are transferred during synthesis of these compounds is still missing, especially when cubic close-packed (ccp) anion sublattices are involved, as it is the case for spinel, layered, or rock-salt systems. In the present study, a series of layered Li(Ni,Co,Mn)O 2 oxides was chosen as target materials to elucidate the underlying formation mechanism of these compounds during high-temperature lithiation reaction. The consistent experimental results demonstrate that, as lithium ions are inserted from surface to bulk, some transition metal cations located within the bulk of crystallites are able to diffuse to the near-surface region. They create cation vacancies for the inserted lithium ions, the mass transport behavior of these elements is driven by chemical potential gradient. Concurrently, oxygen anions from lithium oxides and/or ambient oxygen are adsorbed and incorporated into the ccp oxygen lattice on the surface structure, connecting the relocated transition metal cations and the incorporated lithium ions by forming ionic bonds. This process is concomitant with crystal growth, surface reorganization caused by phase transformation, occurrence and disappearance of pores.

Energy Storage Materials, May 1, 2023

ChemPhysChem, Dec 7, 2017

Thermal stability of Lithium-rich layered oxide with the composition Li(Li1/6Ni1/6Co1/6Mn1/2)O2-x... more Thermal stability of Lithium-rich layered oxide with the composition Li(Li1/6Ni1/6Co1/6Mn1/2)O2-xFx (x=0.00 and 0.05) was evaluated for use as a cathode material in lithium ion batteries. Thermogravimetric analysis, evolved gas analysis, and differential scanning calorimetry showed that upon fluorine doping, degradation of the lithium-rich layered oxides commences at higher temperatures, and the exothermic reaction is suppressed. Hot box tests also revealed that the prismatic cell with the fluorine-doped powder did not explode, while that with undoped one exploded at ~135°C with a sudden temperature increase. X-ray diffraction analysis indicated that fluorine doping imparts the lithium-rich layered oxide with better thermal stability by mitigating the oxygen release at elevated temperatures that causes the exothermic reaction with electrolyte. The origin of the reduced oxygen release from the fluorinated lithium-rich layered oxide was also discussed.

Powder Diffraction, May 9, 2017

Commercial anodes with different state of charge are investigated by X-ray diffraction technique ... more Commercial anodes with different state of charge are investigated by X-ray diffraction technique using Rietveld method for data collected with standard laboratory equipment. It is shown that full profile refinement gives good approximation for quantitative description of the charge/discharge process and may be used for estimation of real state of charge (SoC). Careful analysis of the diffraction profile with Rietveld method allows us to quantitatively distinguish the contribution of different LixC6 phases and estimate the real SoC.

ChemInform, Apr 28, 2011

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Advanced Science, Feb 15, 2023

Glass Physics and Chemistry, Dec 1, 2009

Films of the binary compound AgI and the two-phase composite 0.7AgI • 0.3ZnO have been produced u... more Films of the binary compound AgI and the two-phase composite 0.7AgI • 0.3ZnO have been produced using laser ablation. The temperature dependences of the electrical resistivity of samples prepared in the form of AgI pellets pressed from a fine-grained powder and samples in the form of films of the AgI compound and the 0.7AgI • 0.3ZnO two-phase composite have been investigated using impedance spectroscopy. The sizes of particles in all the samples studied have been estimated by the Scherrer method. It has been shown that zinc oxide in the 0.7AgI • 0.3ZnO two-phase composite can play the role of an dispersing agent for AgI crystallites. The phase compositions of the initial materials and films, as well as the degree of stress of crystals in all the samples under investigation, have been examined using X-ray diffraction analysis. It has been demonstrated that diffraction reflections from 0.7AgI • 0.3ZnO two-phase composite films are shifted toward shorter interplanar distances as compared to the reflections from the other samples, which indicates the presence of mechanical stresses in this composite.

Glass Physics and Chemistry, Aug 1, 2010

Nanocomposites based on chalcogenide glasses have been synthesized. A differential thermal analys... more Nanocomposites based on chalcogenide glasses have been synthesized. A differential thermal analysis of (As 2 Se 3) 1-x (AgI) x and (As 2 Se 3) 1-x (AgBr) x (0 ≤ x ≤ 0.5) samples has been performed. The size of nanofragments that undergo elementary structural transformations has been evaluated. The data obtained are in agreement with the evaluated sizes of X ray coherent scattering regions. The electrical properties of the glasses under consideration have been studied using impedance spectroscopy in the temperature range 293-393 K. It has been demonstrated that the ionic component of the electrical conductivity dominates in glasses with a high content of silver halide.

RSC Advances, 2018

The possibility of H 2 molecule adsorption on the basal plane of monolayer TiS 3 at various sites... more The possibility of H 2 molecule adsorption on the basal plane of monolayer TiS 3 at various sites has been studied. Among the studied adsorption sites, few sites were found to be suitable for physisorption with binding energy up to 0.10 eV per H 2. To increase the activity of hydrogen sorption, the possibility of generating S-vacancies, by removing sulfur atoms from the basal plane of monolayer TiS 3, was investigated. Despite the fact that the structures containing vacancies were found to be stable enough, there was no increase in the activity towards hydrogen adsorption. The same effect was obtained with the use of common methods of increasing of the H 2 adsorption energy: the decoration of the twodimensional material with alkali metals (Li, Na). This might be caused by the negatively charged surfaces of single layer TiS 3 , which hinder the increase in binding by alkali metals through a weak electrostatic interaction.

Advanced Functional Materials, Feb 26, 2021

Deciphering the sophisticated interplay between thermodynamics and kinetics of high‐temperature l... more Deciphering the sophisticated interplay between thermodynamics and kinetics of high‐temperature lithiation reaction is fundamentally significant for designing and preparing cathode materials. Here, the formation pathway of Ni‐rich layered ordered LiNi0.6Co0.2Mn0.2O2 (O‐LNCM622O) is carefully characterized using in situ synchrotron radiation diffraction. A fast nonequilibrium phase transition from the reactants to a metastable disordered Li1−x(Ni0.6Co0.2Mn0.2)1+xO2 (D‐LNCM622O, 0 < x < 0.95) takes place while lithium/oxygen is incorporated during heating before the generation of the equilibrium phase (O‐LNCM622O). The time evolution of the lattice parameters for layered nonstoichiometric D‐LNCM622O is well‐fitted to a model of first‐order disorder‐to‐order transition. The long‐range cation disordering parameter, Li/TM (TM = Ni, Co, Mn) ion exchange, decreases exponentially and finally reaches a steady‐state as a function of heating time at selected temperatures. The dominant kinetic pathways revealed here will be instrumental in achieving high‐performance cathode materials. Importantly, the O‐LNCM622O tends to form the D‐LNCM622O with Li/O loss above 850 °C. In situ XRD results exhibit that the long‐range cationic (dis)ordering in the Ni‐rich cathodes could affect the structural evolution during cycling and thus their electrochemical properties. These insights may open a new avenue for the kinetic control of the synthesis of advanced electrode materials.

Energy Storage Materials, Mar 1, 2019

Cobalt sulfides based on conversion mechanisms are considered as promising anode materials for so... more Cobalt sulfides based on conversion mechanisms are considered as promising anode materials for sodium-ion batteries due to their appropriate working voltage and high practical capacities. But the severe volume change and structure transformation make their cycle stability and rate capability unsatisfactory. In this study, metal-organic framework derived Co 9 S 8 @carbon yolk-shell nanocages (Co 9 S 8 @CYSNs) was prepared and its direct conversion mechanism was carefully demonstrated for the first time by various spectroscopic techniques and first-principles calculations. The unique hierarchical structure of Co 9 S 8 @CYSNs composed of Co 9 S 8 nanoparticles dispersed in amorphous carbon matrix inside a rigid carbon shell was capable of accelerating the conversion reaction, shortening the Na + diffusion distance and providing a fast electron transport channel. Benefiting from the accelerated electrochemical reactions and high activities of nanosized particles, the Co 9 S 8 @CYSNs exhibited a large discharge capacity of 549.4 mAh g-1 at 0.1 A g-1. In addition, a superior rate performance of 100 mAh g-1 at 10 A g-1 and excellent cycle stability with a very low capacity 2 decay of 0.019 % per cycle over 800 cycles at 10.0 A g-1 were achieved because of the confine effect of the carbon shell and improved charge transfer reactions of the electrode.

Electrochimica Acta, Aug 1, 2014

ABSTRACT Ni-rich mixed metal oxides (LiNi0.80Co0.15Mn0.05O2) as a high capacity cathode material ... more ABSTRACT Ni-rich mixed metal oxides (LiNi0.80Co0.15Mn0.05O2) as a high capacity cathode material for lithium ion battery are synthesized in two different heat-treatment atmospheres of air and oxygen, respectively. A cell with LiNi0.80Co0.15Mn0.05O2 heat-treated in the oxygen atmosphere shows better electrochemical performance of initial (193.7 mAh/g) and retention (185.2 mAh/g) capacities than a cell with the cathode material heat-treated in the air atmosphere (initial capacity: 185.2 mAh/g and retention capacity: 172.0 mAh/g). In order to find the reasons of the different electrochemical performance, the samples have been characterized in detail by X-ray diffraction and scanning electron microscopy. The structural differences are revealed at the nanometer scale from the experimental works of scanning transmission electron microscopy images mapped with orientation and reliability indices and electron energy loss spectroscopy. The NiO phase of the rock salt structure is considerably developed on the surfaces of the materials in the less oxidative environment of the air atmosphere; this is related to the poor electrochemical performances.

Journal of Materials Chemistry C, 2023

Herein we report the Peierls-like transition in the high-pressure ilmenite-type MnVO 3. The first... more Herein we report the Peierls-like transition in the high-pressure ilmenite-type MnVO 3. The first-order structural transition from a low-temperature P % 1 to a high-temperature R % 3 occurs at 475 K, accompanied by a semiconductor to metal-like transition. The triclinic distorted phase presents a V-V dimerization with a short B2.85 Å bond formation at 300 K. Below 80 K MnVO 3 orders antiferromagnetically with a small ferromagnetic component. Neutron diffraction reveals that both Mn and V cations contribute to the magnetic ordering, contrary to what expected on the V-V dimer formed. Extended Hückel and DFT calculations expose that the formation of covalent pairing is only partially achieved, contrary to the MgVO 3 and CoVO 3 counterparts.