Nina V. Kosova

Institute of Solid State Chemistry and Mechanochemistry · Group of Materials for Li-Ion batteries

The search for new materials that could improve the energy density of Li-ion batteries is one of today's most challenging issues. Many families of transition metal oxides as well as transition metal polyanionic frameworks have been proposed during the past twenty years. Among them, manganese oxides, such as the LiMn2O4 spinel or the overlithiated o...

A family of lithium mixed transition-metal pyrophosphates Li2Fe1−yMnyP2O7/C (0≤y≤1) has been prepared by mechanochemically assisted solid state synthesis using a high-energy planetary mill AGO-2. The samples were studied by X-ray powder diffraction (XRD) including Rietveld refinement, Fourier transform infrared spectroscopy (FTIR), Mössbauer spectr...

LiCo1-yFeyPO4 solid solutions (0≤y≤1) were prepared by mechanochemically assisted carbothermal reduction of Co3O4 and Fe2O3. Mechanical activation was performed using a high-energy planetary mill AGO-2. The samples were characterized in detail by X-ray powder diffraction (XRD) using Rietveld refinement, Fourier transform infrared spectroscopy (FTIR...

Single-phase LiVPO 4 F and LiVPO 4 F/Li 3 V 2 (PO 4 ) 3 nanostructured composite cathode materials were prepared by heating of the VPO 4 +LiF mechanochemically activated mixture to 700 °C and subsequent quick or slow cooling to room temperature, respectively. The formation of the composites was proved by a combination of different physico-chemical...

Homogeneous submicron carbon-coated LiFe1−yMnyPO4 solid solutions in the whole concentration range (0≤y≤1) were obtained by mechanochemically assisted carbothermal reduction of Fe2O3 and MnO2, using high-energy planetary mill. The samples were studied through a combination of several techniques: XRD, TEM, FTIR, Mössbauer, 6,7Li and 31P NMR spectros...

In this work, a comparative study of the conductive properties of the PEO-NaClO4:NZSP composite solid polymer electrolyte (SPE) films was carried out in a wide range of the NZSP filler content (5–250 wt%), and the “ceramics-in-polymer” and “polymer-in-ceramics” fields were studied. The optimal composition of EO:NaClO4 with molar ratio is 10:1 to ob...

Li-excess cathode materials with a disordered rock-salt structure (DRX) Li1.2Ti0.4Mn0.4O2 and Li1.3Nb0.3Mn0.4O2 were prepared by mechanochemically assisted solid-state synthesis at various synthesis conditions using different lithium sources (Li2O and LiOH). As-prepared samples were characterized by X-ray powder diffraction (XRD), thermal analysis...

In the present work, we studied crystal phases in the Li3-xNaxV2(PO4)3 system over a wide range of x prepared by four synthesis methods: mechanochemically assisted solid-state synthesis, 'soft chemistry' sol-gel approach, chemical (CIE) and electrochemical (EIE) ion exchange starting from Li3V2(PO4)3 (anti-NASICON, P21/c S.G.), and Na3V2(PO4)3 (NAS...

The effect of the nature of the transition metal ion (electron configuration 3d0 and 4d0) on the local structure and electrochemical properties of lithium-rich oxyfluorides with disordered rock-salt structure Li1 + x(MеMn3+)1 – xO2 – yFy, where Mе = Ti4+, Nb5+, 0.2 ≤ x ≤ 0.288 and 0.05 ≤ y ≤ 0.15 is studied. The compounds are thoroughly investigate...

The effects of mechanical activation in a planetary mill and the addition of fusible additives on the conduction properties of the Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte with the NASICON structure are compared. According to the results of impedance measurements, the mechanical activation increases the total conductivity of this material fro...

Lithium-ion batteries based on high-voltage cathode materials, such as LiCoPO4, despite being promising in terms of specific power, still suffer from poor cycle life due to the lower stability of common non-aqueous electrolytes at higher voltages. One way to overcome this issue might be decreasing the working potential of the battery by doping LiCo...

According to the extensive studies in the field of high-energy cathode materials for lithium-ion batteries (LIBs), Mn-based oxyfluorides Li1.2Mn0.6+0.5yNb0.2–0.5yO2–yFy with Li-excess and cation-disordered rock-salt structure capable of reversible cationic and anionic redox reactions are among the most promising candidates. In this work, a series o...

Magnetic properties of the submicron carbon-coated LiFe1−xMnxPO4 (x = 0, 0.01, 0.1) systems were investigated using the electron spin resonance (ESR) method. The observed ESR signal consisted of two broad resonance lines with a Lorentzian line shape for all samples. The temperature dependence character of the integral intensity of these lines chang...

The solid-state reaction between NaF and VPO4 is widely used to produce Na3V2(PO4)2F3, a promising cathode material for sodium-ion batteries. In the present work, the mechanism and kinetics of the reaction between NaF and VPO4 were investigated, and the effect of preliminary high-energy ball milling (HEBM) was studied using in situ time-resolved sy...

TiNb2O7 anode material with a Wadsley–Roth crystallographic shear structure was prepared by solid-state synthesis at a relatively low temperature (1000 °C) and a short calcination time (4 h) using preliminary mechanical activation of the reagent mixture. The as-prepared final product was then ball milled in a planetary mill with and without carbon...

Lithium-excess oxides Li1.2Ti0.4Mn0.4O2 and Li1.3Nb0.3Mn0.4O2 with a disordered rock-salt structure and Mn3+/Mn4+ as a redox couple were compared to analyze the effect of different d0 metal ions on the local structure and Li+ ion migration. These cathode materials were obtained by mechanochemically assisted solid-state synthesis. Using XRD, 7Li NMR...

Carbon-coated LiFe0.5Mn0.5PO4 (C-LFMP) cathode materials were obtained by two-step mechanochemically assisted solid-state synthesis. After mechanical activation and heat treatment of the reagent mixture at 400 °C, the pre-prepared carbon-free LFMP-400 was obtained, which was then ball milled with three different carbon precursors: carbon black (CB)...

The discovery of new chemistries superior to modern lithium intercalation cathodes is of great scientific and technological importance. The cathodes play a key role in the performance of lithium-ion batteries (LIB). While layered oxide cathodes deliver high capacity, polyanion compounds show structural stability, operational safety, tunable redox p...

Nanostructured carbon–coated composite cathode materials LiFe0.5Mn0.5PO4/C (LFMP/C) are prepared by the mechanochemically assisted solid-state synthesis using different reagent mixtures and carbon as reducing and covering agent. The effect of the precursors, gas release during the solid-state reaction, and of the intensity of high-energy ball milli...

In this work, a detailed study of the mechanochemical approach to preparation of Na3V2(PO4)2F3/C cathode material with a porous structure is carried out. It is found that mechanical activation (MA) contributes to obtaining a single-phase material with a uniform distribution of elements at the nanoscale, reducing the particle size, and forming a mes...

NASICON-type NaFe2(PO4)(SO4)2 (NFPS) electrode material is successfully synthesized via a rheological route. DSC/TG analysis shows that it is thermally stable up to 760 °C. A carbon composite NFPS/C was obtained using ball milling. NFPS and NFPS/C were investigated as cathode and anode materials for sodium-ion batteries. Analysis of migration paths...

Jarosite NaFe3(SO4)2(OH)6 (NFSOH) with a trigonal structure (R-3m space group) was prepared by the hydrothermal synthesis at 150°C and then ball milled with carbon black. Crystal and local structure, morphology, thermal stability, conductivity and electrochemical properties of the as-prepared composite NaFe3(SO4)2(OH)6/C (NFSOH/C) were investigated...

In this current work, high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) decorated with AlF3 thin layer was successfully synthesized and investigated for the application in Li-ion batteries (LIBs). The electrochemical properties and dissolution behavior of transition metals of the AlF3-modified LNMO electrodes were investigated, especially at elevated tempe...

The sample with a nominal composition ‘NaVPO4F’ is prepared by the mechanochemically assisted solid-state synthesis using quenching. The detailed study of its crystal and local structure is conducted by means of XRD, FTIR and solid-state 31P NMR spectroscopy in comparison with Na3V2(PO4)2F3. It is shown that the as-prepared ‘NaVPO4F’ has a multipha...

Sodium polyanion phosphates can be used as cheap cathode materials for Na-ion batteries. One such material is sodium-iron ortho-pyrophosphate Na4Fe3(PO4)2P2O7 (hereafter NFPP). This compound demonstrates small changes in the volume of the unit cell during cycling, which indicates the possibility of its long-term operation, has an average operating...

Carbon-free LiFe0.5Mn0.5PO4 and carbon-coated LiFe0.5Mn0.5PO4/C cathode materials were prepared by the mechanochemically assisted solid-state synthesis. The influence of the carbon coating on the porous structure, morphology, conductivity, and electrochemical characteristics of the cathode materials was analyzed using scanning electron microscopy (...

In the present work, sodium-vanadium fluorophosphates were prepared from the same reagents using the solid-state and the hydrothermal routes. The differences in phase composition, crystal structure, morphology, particle size distribution, and electrochemical properties of the as-prepared products are discussed.

Known minerals such as bonshtedtite Na3Fe(PO4)(CO3) and sodium-jarosite NaFe3(SO4)2(OH)6 were prepared using the hydrothermal synthesis and studied as cathode materials for sodium-ion batteries. Because of low decomposition temperature of these materials, the creation of the carbon coating using high-temperature pyrolysis of organic compounds is ra...

The Na⁺/Li⁺ electrochemical exchange in Na3FePO4CO3 (NFPC) carbonophosphate is studied for the first time in a hybrid cell using Li metal anode and Li-based electrolyte. The resulting ion-exchanged product is investigated. It is shown that the complete substitution of Na for Li is not achieved. The Na⁺/Li⁺ electrochemical exchange does not cause no...

The present study describes the effect of the NaF/VPO⁠4 ratio (3/2 or 1/1) and the conditions of the mechanochemically assisted solid-state synthesis (slow cooling or quenching) on the composition, structure, morphology, and electrochemistry of the final products in the Na-V-P-O-F system. It has been shown that the cooling rate doesn't affect much...

Hybrid supercapacitors (HSCs) based on the mechanochemically prepared LiCoPO4 samples with different specific surface area and porosity as cathodes and the activated carbon (AC) Kuraray K-50 as anode were fabricated and studied. The effect of porosity and specific surface area of LiCoPO4 on its performance in HSC was investigated. The porosity was...

The mixed sodium-iron ortho-pyrophosphate Na4Fe3(PO4)2P2O7 (NFPP) is a promising Na-containing cathode material with the highest operating voltage among sodium framework structured materials. It operates both in Na and Li electrochemical cells. When cycled in a hybrid Li/Na cell, a competitive co-intercalation of the Li+ and Na+ ions occurs at the...

Pristine Na3FePO4CO3 (NFPC) with the monoclinic structure and the P21/m space group was prepared by hydrothermal synthesis at 120 °C. To increase the conductivity of NFPC, it was ball milled with carbon using a SPEX 8000 mill. Crystal and local structure, morphology, thermal stability, conductivity and electrochemical properties of NFPC and NFPC/C...

The Na3FePO4CO3/C composites have been prepared using mechanical activation. This leads to structural disordering of the Na3FePO4CO3 crystal structure and oxidation of the Fe²⁺ ions to Fe³⁺. The first charge of the composites is an irreversible process realizing at ∼4 V due to the Fe³⁺/Fe⁴⁺ redox couple. The as-prepared composites show good cycleab...

We have developed and tested cell for laboratory operando diagnostics of Li-ion cathode materials. Local atomic and electronic structure of LiFe1-xMnxPO4 olivine cathode was studied by means of Fe and Mn K-edges XAS and Mössbauer spectroscopy. Analysis of XAS data allows us to follow the structural and oxidation state changes occurring during the c...

A comparative study of structure, morphology and electrochemistry of LiFe0.5Mn0.5PO4 (LFMP) synthesized by the mechanochemically assisted solid-state synthesis (SS) and the solvothermal synthesis (ST) was performed using XRD, Mӧssbauer, SEM, and galvanostatic cycling. LFMP-SS consists of irregular-shaped submicron particles and shows two two-phase...

The Na+/Li+ substitution in Na3V2(PO4)2F3 is studied using different synthesis approaches: equilibrium and non-equilibrium. In the equilibrium solid-state process, the reagent mixtures with various Na/Li ratios are preliminary mechanically activated using a high-energy AGO-2 planetary mill and then annealed in an Ar flow. Non-equilibrium chemical N...

La3+ modification of Na3V2(PO4)2F3 was performed by the direct mechanochemically assisted solid-state synthesis of the Na3V2−xLax(PO4)2F3 compositions, and by the LaPO4 coating of the as-prepared Na3V2(PO4)2F3 via the precipitation method. It has been shown that no noticeable substitution of the V3+ ions by the La3+ ions occurs in the Na3V2(PO4)2F3...

Na4Fe3(PO4)2P2O7 (NFPP) was synthesized by the fast and facile mechanochemically assisted solid-state route using iron oxalate as a precursor. By means of XRD, FTIR, and Mӧssbauer spectroscopy, it was found that NFPP prepared by annealing the activated mixture at 450 °C is the most homogeneous phase and shows the best electrochemical behavior when...

A comparative investigation of the crystal structure, morphology and electrochemistry of LiFe0.5Mn0.5PO4 (LFMP) prepared by the mechanochemically assisted solid-state synthesis (SS) and the solvothermal synthesis (ST) was performed. The as-prepared samples were studied by XRD, FTIR, Raman, Mӧssbauer, SEM, TEM, galvanostatic cycling, GITT, and EIS....

In this work, we report a detailed study of the high energy density nanostructured Li4-xMn2O5-Li2O composite with a large discharge capacity of 355 mAh/g, constituting the highest value ever reported for lithium manganese oxide electrodes. Its high capacity was previously wrongly attributed to the sole participation of Li4-xMn2O5 (Li4). However, mo...

In this work, a fast and facile mechanochemical approach has been used to prepare sodium vanadium fluorophosphates cathode materials with two compositions of NaVPO4F and Na3V2(PO4)2F3 to compare their structure and electrochemical behavior in hybrid-ion cells. It is established that Na3V2(PO4)2F3 is a single phase material with a tetragonal structu...

Using Rietveld-refined X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and electrochemical cycling, it was established that among sodium vanadium fluorophosphate compositions Na1+yVPO4F1+y (0 ≤ y ≤ 0.75), the single-phase material Na1.5VPO4F1.5 or Na3V2(PO4)2F3 with a tetragonal structure (the P42/mnm S.G.) is formed only fo...

Sodium iron pyrophosphates Na2−xFe1+x/2P2O7 (x = 0; 0.44) have been prepared by mechanochemically assisted solid-state synthesis. The materials were comprehensively characterized and compared by XRD with Rietveld refinement, FTIR, Mössbauer spectroscopy, ²³Na and ³¹P MAS NMR, SEM, EDX, galvanostatic cycling, and GITT. The structure of the as-prepar...

In this work, XRD, EDX, Mössbauer and NMR spectroscopy were used to study chemical and electrochemical Na⁺/Li⁺ ion exchange in the sodium iron pyrophosphate Na1.56Fe1.22P2O7 with a triclinic symmetry, S. G. P-1, and sodium vanadium fluorophosphate Na3V2(PO4)2F3 with a tetragonal symmetry, S. G. P42/mnm, cathode materials. Electrochemical Na⁺/Li⁺ io...

Na2FeP2O7 sodium iron pyrophosphate with a triclinic symmetry (the space group P-1) has been prepared by mechanochemically assisted solid state synthesis. Electrochemical performance of the pristine Na2FeP2O7, NaFeP2O7 prepared by chemical oxidation with NO2BF4 and NaLiFeP2O7 obtained by non-oxidative Na⁺/Li⁺ ion exchange with LiBr were studied by...

The pure LiNi 0.5 Mn 1.5 O 4 and doped spinels LiNi 0.5-x Mn 1.5-y M x+y O 4 (M = Co, Cr, Ti; x + y = 0.05) were prepared by mechanochemically assisted solid state synthesis using a high-energy AGO-2 planetary mill. The activated samples were annealed at 700 and 800 °C in oxygen and then characterized by x-ray powder diffraction (XRD) and neutron p...

Sodium-based insertion materials are of interest for low-cost and large-scale Na- and Li-ion batteries. Substantial research effort has been invested during the previous years to produce electrode materials for sodium batteries that will allow for facile intercalation of Na-ions at suitable potentials. Amongst the cathode materials investigated, a...

A series of (1 − y)LiCoPO4·yLi3V2(PO4)3 with 0 ≤ y ≤ 1 was prepared via mechanochemically assisted carbothermal reduction at 750 °C. Structure and electrochemistry were studied by a complex of physico-chemical methods including XRD, NPD, FTIR, NEXAFS, TEM, EDX STEM, and galvanostatic cycling. It has been shown that only a small amount of V ions inc...

Due to their low weight, high energy densities and long cycle life, the battery scientific community is still trying to develop new high capacity cathodes materials in order to increase the energy density of storage devices [1]. After a composition screening, a new material family has been discovered in the Li-Mn-O system and has been investigated...

A comparative structural study of LiMPO4 (M = Mn, Fe, Co, Ni) orthophosphates and Li2MPO4F (M = Co, Ni) fluorophosphates obtained by mechanochemically assisted solid-state synthesis is performed using powder XRD, IR, and NMR spectroscopy methods. It is shown that all compounds crystallize in the orthorhombic symmetry (space group Pnma). Lattice par...

In this study, different mechanochemical reactions were used to prepare nanostructured electrode materials for lithium-ion batteries. They include mechanochemically assisted acid-base interactions of basic LiOH with anhydrous acidic manganese and cobalt (hydro)oxides to prepare layered and spinel-structured cathode materials. Redox reactions (carbo...

This work represents a review on nanostructured composite electrode materials prepared by mechanochemically assisted solid-state synthesis using a high-energy mechanical activation (MA). As-developed approaches include: 1) Joint MA of two active cathode materials; 2) Direct mechanochemically assisted solid-state synthesis from a multicomponent reag...

Vanadium and titanium doped orthophosphates LiFe 0.9 M 0.1 PO 4 with an olivine-type structure (space group Pnma) were prepared by mechanochemically assisted solid state synthesis using a high-energy AGO-2 planetary mill and post-annealing at 750 °C. It has been established that the V and Ti ions do not fully substitute for Fe 2+ in the LiFePO 4 st...

Single-phase LiVO3 with a monoclinic structure (S.G. C2/c) was prepared by mechanochemically assisted solid state synthesis using V2O5 and Li2CO3 as raw materials. The reagent mixtures, activated by means of a high-energy planetary mill AGO-2, were annealed at 350, 450 and 550 °C in air. Thus-prepared LiVO3 samples were characterized by XRD using t...

Nanostructured NaFePO4 (space group Pmnb) and Na2FePO4F (space group Pbcn) were prepared by a quick and facile mechanochemically assisted solid state synthesis. Low-crystalline Na2FePO4F was formed as a result of direct mechanochemical reaction of NaFePO4 with NaF. It crystallizes upon subsequent heating to 600 °C and decomposes at higher temperatu...

A series of the mixed sodium-lithium iron fluorophosphates Na2-xLixFePO4F with 0≤x≤1 has been synthesized by mechanochemically assisted solid-state route. Their crystal and local structure, and electrochemical properties were investigated by X-ray and neutron powder diffraction, 57Fe Mössbauer spectroscopy and electrochemical measurements with GITT...

Sodium-based cathode materials are interested both for sodium-ion and lithium-ion batteries application. In 2007, Ellis et al. [1] synthesized a new sodium-based flourophosphate Na2FePO4F. This material operates at 3.3 V and has two-dimensional (2D) pathways for intercalation/deintercalation of alkaline ions and a single-phase (solid solution) mech...

Many efforts have been made to turn insulating compounds into attractive electrode materials, including nanosizing, carbon nanopainting and metal doping. A new approach to enhance high-rate capability of materials with poor electric conductivity is based on the development of two-component composites comprising of low-conductive and high-conductive...

Many efforts have been made to turn insulating compounds into attractive electrode materials, including nanosizing, carbon nanopainting and metal doping. A new approach to enhance high-rate capability of materials with poor electric conductivity is based on the development of two-component composites comprising of low-conductive and high-conductive...

Sodium-based cathode materials are interested both for sodium-ion and lithium-ion batteries application. In 2007, Ellis et al . [1] synthesized a new sodium-based flourophosphate Na 2 FePO 4 F. This material operates at 3.3 V and has two-dimensional (2 D ) pathways for intercalation/deintercalation of alkaline ions and a single-phase (solid solutio...

Two synthetic processes, a single-step and a two-step one, both using preliminary mechanical activation (MA) of reagent mixtures, were investigated to prepare Li2CoPO4F. In situ and ex situ X-ray study of the formation and decomposition of Li2CoPO4F under heating and cooling was performed. It was found that Li2CoPO4F was already formed at the stage...

In situ synchrotron diffraction study of phase transformations under cycling of nano-sized phase-homogeneous and carbon-coated LixFe0.5Mn0.5PO4 prepared by mechanochemically assisted carbothermal reduction route demonstrates the occurrence of single-phase reactions in a wide intermediate region upon delithiation and lithiation (0.4<x<0.7) and addit...

This short review reports on the synthesis of nanosized electrode materials for lithium-ion batteries by mechanical activation (MA) and studies of their properties. Different structural types of compounds were considered, namely, compounds with a layered (LiNi1 − x − y Co x Mn y O2), spinel (LiMn2O4, Li4Ti5O12), and framework (LiFePO4, LiTi2(PO4)3)...

Solid state mechanical activation method was applied for surface modification of LiMn2O4 by Li–M–O (M=Co, Co+Ni) and for preparation of composite mixed LiMn2O4/LiCoO2 cathode materials. Pristine LiMn2O4 was ground with correspondent precursors (for coating) or with LiCoO2 (for composites) in high-energy planetary mills and then heat treated at diff...

Mechanochemical synthesis of dicalcium ferrite with the perovskite structure from anhydrous or hydrated calcium and iron oxides was studied by XRD, DTA, IR spectroscopy, and Mossbauer measurements. The formation of Ca2Fe2O5 from anhydrous oxides during mechanical activation (MA) occurs at a high rate. Although hydrated oxides do not react during MA...

A soft mechanochemical synthesis approach was applied to prepare some fi ne particulate lithium-containing compounds with a spinel (LiMn2-xMxO4, Li4Ti5O12), layered (LiNi1-x-yCoxMnyO2, LiV3O8) and framework structure (LiFePO4, Li2FeSiO4, LiTi2(PO4)3). It consists of the fast formation of amorphous or low-crystalline precursors during mechanical act...

Nanosized LiCoO2 and LiMn2O4 were prepared by preliminary mechanical activation of the mixtures of Li2CO 3 with Co3O4 and Li2CO3 with MnO or MnO2 in the presence of carbon in high-energy planetary mill and annealed at 750-800°C in air. Added carbon inhibits the particles' interaction during mechanical activation and their growth during annealing. T...

LiFePO 4 and LiFePO 4/C composites were prepared by mechanical activation process using Fe 3+ precursor (Fe 2O 3) in comparison with Fe 2+ precursor (FeC 2O 4·2H 2O). The reaction mechanism, phase composition, particle size and electrochemical performance of as-prepared materials were examined by thermal analysis, X-ray diffraction, Mössbauer spect...

Submicrometer and phase-pure LiFePO4 was prepared by carbothermal reduction of Fe2O3 using a preliminary mechanical activation. The reaction mechanism, particle size, and electrochemical performance of as-prepared LiFePO4 were studied and compared with LiFePO4 obtained from the Fe2+ precursor (FeC2O4 center dot 2H(2)O) using thermal analysis, X-ray...

The complex oxides Li1 + xNi1 / 3Co1 / 3Mn1 / 3O2 were obtained by solid state method. The conclusion about influence of lithium concentration on Ni2+ and Ni3+ ions ratio in Li1 + xNi1 / 3Co1 / 3Mn1 / 3O2 is made. Monotonous decrease of g-factor value identified by EPR method testifies the intensification of local exchange interactions with tempera...

Solid state mechanical activation (MA) followed by subsequent short-time heat treatment has been used to prepare some cathode (e.g., LiNi(1-y)Co(y)O(2)), anode (e.g., Li(2)Ti(3)O(7)) and solid state electrolyte (e.g., LiTi(2)(PO(4))(3)) materials with enhanced characteristics for lithium-ion batteries. The method allows one to realize intimate mixi...

Solid state mechanical activation method was applied for surface modification of LiCoO2 by simple oxides (Al2O3, TiO2, MgO and Li2O•2B2O3) and of LiMn2O4 by LiMO2 (M=Co, Ni). Pristine materials were ground with correspondent precursors and then heat treated at different temperatures. As prepared materials were studied by XRD, 6,7Li and 27Al MAS NMR...

New composite cathode materials xLiMn2O4/(1 − x) LiCoO2(x = 0.7, 0.6, 0.5 и 0.4) were obtained by mechanical activation. According to scanning electron microscopy data, the process was accompanied by pronounced dispersion and fine mixing of the initial components. In the course of the preparation and electrochemical cycling of the composites, LiMn2...

The surface chemistry of the Al2O3-coated LiCoO2 prepared under heat treatment at 80–800 °C was studied by SEM, XRD, IR, XPS and NMR spectroscopy combined with electrochemical testing. It is shown that the particle bulk is free from dopant. XPS Al2s core-level spectrum of the coated LiCoO2 differs from that of α-Al2O3 and is associated with Al oxyh...

LiTi2(PO4)(3) (LTP) and Li1.3Al0.3Ti1.7(PO4)(3) (LATP) (S. g. R-3c) have been prepared using conventional ceramic and mechanical activation (MA) methods. It has been shown that preliminary mechanical activation of initial mixtures leads to different nature and amount of dielectric admixtures in the final product after heat treatment at 800-1000 deg...

The cathode materials of the composition LiNi1 − 2x Cox Mnx O2 (x = 0.1, 0.2. 0.33) synthesized from the Ni, Co, Mn mixed hydroxides and LiOH by using mechanical activation method are studied. It is shown that all synthesized compounds have layered structure described by the space group R-3m. With the decreasing of the nickel content the cell volum...

It has been shown that varying conditions of co-precipitation processes, two types of mixed Ni–Mn–Co hydroxides: either brucite, or hydrotalcite-like (LDHs)—with different Ni/Mn/Co ratio can be prepared. According to XPS study, these hydroxides are mixed-valence materials: Ni ions present in 2+ oxidation state, whereas Mn and Co ions are in 3+/4+ a...

It has been shown that crystal and local structure of LiCoO2 does not noticeably change after surface modification with different inert oxides (MgO, Li2O·2B2O3, Al2O3, ZnO, ZrO2) using wet chemical method. However, in the case of LiCoO2/Al2O3, a small amount of Co3O4 phase was observed. Chemical delithiation study shows better structural and chemic...

A study of the LiNi1−x−yCoxMnyO2 (x=y=0.1; 0.2; 0.33) cathode materials prepared from mixed hydroxides and LiOH using the method of mechanical activation has been performed. All as prepared materials were indexed in the R-3m space group. The cell volume and the degree of structural disordering decrease with reducing of Ni content. According to XPS...

We have investigated LiNi1 − x − y Cox Mny O2 (x = y = 0.1, 0.2, 0.33) cathode materials synthesized from mechanically activated mixtures of lithium hydroxide and nickel cobalt manganese hydroxide. The materials have a layered structure (sp. gr. \(R\bar 3m\)). Their unit-cell volume and the degree of disordering in their structure decrease with dec...

The modular automated electrochemical cells cycling in galvanostatic and galvanostatic intermittent titration techniques test setup, having a wide range of determined currents of the charge/discharge and measured signals of electrochemical cells is described. The software is developed, allowing operating process of cycling and providing intuitively...