A5035900093- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Supercapacitor Materials and Fabrication
- Extraction and Separation Processes
- Magnetic and transport properties of perovskites and related materials
- Transition Metal Oxide Nanomaterials
- Catalytic Processes in Materials Science
- Metal complexes synthesis and properties
- Multiferroics and related materials
- Advanced Battery Technologies Research
- Microwave Dielectric Ceramics Synthesis
- Lanthanide and Transition Metal Complexes
- Ferroelectric and Piezoelectric Materials
- Semiconductor materials and devices
- Thermal Expansion and Ionic Conductivity
- Electrochemical Analysis and Applications
- Magnetism in coordination complexes
- Magnetic Properties and Synthesis of Ferrites
- Pigment Synthesis and Properties
- Advanced Condensed Matter Physics
- Advanced battery technologies research
- Chemical Synthesis and Characterization
- Inorganic Chemistry and Materials
- Electrical and Thermal Properties of Materials
- Catalysis and Oxidation Reactions
Institute of General and Inorganic Chemistry
2013-2023
Bulgarian Academy of Sciences
2013-2023
Agrobioinstitute
2010-2015
University of Córdoba
1994-1998
International Council on Mining and Metals
1992
Institut de Physique et Chimie des Matériaux de Strasbourg
1992
Sofia University "St. Kliment Ohridski"
1988-1992
Military Medical Academy
1992
Russian Academy of Sciences
1987
We report on a rigorous comparative study of nano- and microparticles spinel as cathode materials for Li-ion batteries. The stability these in /alkyl carbonate solutions temperatures up to was explored. Capacity, cycling, rate capabilities, impedance behavior were also studied. methods included X-ray diffraction, Raman, photelectron, Fourier transform infrared, electron paramagnetic resonance spectroscopies, microscopy, conjunction with standard electrochemical techniques: voltammetry,...
A promising group of inorganic salts recently emerged for the negative electrode advanced lithium-ion batteries. Manganese carbonate combines low weight and significant lithium storage properties. Electron paramagnetic resonance (EPR) magnetic measurements are used to study environment manganese ions during cycling in test cells. To observe reversible into carbonate, preparation by a reverse micelles method is used. The resulting nanostructuration favors capacitive mechanism with good rate...
Sodium-deficient nickel-manganese oxides exhibit a layered structure, which is flexible enough to acquire different layer stacking. The effect of stacking on the intercalation properties P3-Nax Ni0.5 Mn0.5 O2 (x=0.50, 0.67) and P2-Na2/3 Ni1/3 Mn2/3 , for use as cathodes in sodium- lithium-ion batteries, examined. For P3-Na0.67 large trigonal superstructure with 2√3 a×2√3 a×2 c observed, whereas there reduced lattice parameters. In sodium cells, P3 P2 phases intercalate reversibly at...
Noncrystalline solids with LiCoC6H5O7·5H2O and (NH4)3LiCo(C6H5O7)2 compositions were obtained by ethanol dehydration of concentrated lithium−cobalt citrate solutions. Electron spectroscopy solutions solid citrates, as well IR reveals that in one triionized ion chelates Co2+ while two ions surround (NH4)3LiCo(C6H5O7)2. Lithium−cobalt citrates used precursors the formation mixed oxides. At 400 °C, thermal decomposition yields a mixture pseudo-spinel rhombohedral LiCoO2. From...
The effects of composition and preparation temperature on the structure LiMgyNi0.5-yMn1.5O4 (y = 0, 0.25, 0.5) compounds are studied by EPR, FTIR, X-ray, neutron diffraction. For y ≥ cation ordering in a P4332 superstructure takes place increasing annealing from 450 to 750 °C. In contrast, loss octahedral partial reduction transition metals found for LiNi0.5Mn1.5O4 when increases 700 800 EPR behavior LiMg0.5Mn1.5O4 is determined localized Mn4+ ions, whereas residual antiferromagnetic...
The capability of sodium deficient nickel manganese oxides to participate in reactions Li<sup>+</sup>intercalation and Na<sup>+</sup>/Li<sup>+</sup>exchange allows their use as low-cost electrode materials lithium cells.
Lithium–nickel manganese spinel, LiNi1/2Mn3/2O4, is capable to intercalate lithium reversible at a high voltage delivering specific energy when used as cathode material for ion batteries. In this study, the effects of cationic order and particle size distribution on intercalation in high-voltage LiNi1/2Mn3/2O4 spinel are examined by application diffraction spectroscopic techniques. At 400 °C, nonstoichiometric LiNi1/2Mn3/2O4-δ with disordered structure between 10 20 nm obtained. 7Li NMR...
The study demonstrates unusual capabilities of phospho-olivine NaMnPO<sub>4</sub> to intercalate lithium and sodium reversibly, which makes it attractive electrode material instead the conventional analogue LiMnPO<sub>4</sub>.
We report precursor-based methods for low-temperature synthesis of two structure modifications NaMnPO4. The maricite phase is thermodynamically more stable, while the olivine great interest as a positive-electrode material lithium and sodium ion batteries. advantage synthetic procedures formation defectless NaMnPO4 in temperature range 200–400 °C. morphology characterizations are performed by powder XRD, SEM TEM analyses. oxidation state Mn ions determined X-ray photoelectron spectroscopy....
The development of lithium and sodium ion batteries without using metal as anodes gives the impetus for elaboration low-cost environmentally friendly energy storage devices. In this contribution we demonstrate design construction a new type hybrid sodium-lithium cell by unique electrode combination (Li4Ti5O12 spinel negative layered Na3/4Co1/3Ni1/3Mn1/3O2 positive electrode) conventional electrolyte (LiPF6 salt dissolved in EC/DMC). operates at an average potential 2.35 V delivering...
Nongraphitic carbon microbeads were prepared by hydrothermal treatment of a glucose aqueous solution at 180 °C. Impregnation glucose-derived with citric acid was used to control the microbeads' surface and electrochemical properties. The microspherical sample thus obtained exhibited highly disordered nanocrystalline structure low BET area. performance evaluated from discharge/charge experiments in lithium sodium cells, as well impedance spectroscopy measurements. intercalation Li Na...
We report on the behavior of nanometric (LiMNC) as a cathode material for Li-ion batteries in comparison with same submicrometric particles. The LiMNC was produced by self-combustion reaction, and particle size controlled temperature duration follow-up calcination step. X-ray diffraction, scanning electron microscopy, photoelectron spectroscopy, Fourier transform infrared, Raman paramagnetic resonance, inductively coupled plasma, atomic force microscopy were used conjunction standard...
Cobalt-spinel ferrites with a Co3-xFexO4 (x = 0, 1, 2) stoichiometry have been prepared by sol−gel process involving solvent sublimation freeze-drying procedure. SEM micrographs showed the formation of flake-like aggregates yielding macroporous system that ensures good electrolyte−particle contact in iron-containing samples. The analysis electrochemical curves evidenced changes first discharge profiles ascribed to sequential reduction trivalent cobalt ions prior main metallic state Co2FeO4....
In this contribution, new data on the reversible Li+ intercalation in iron substituted sodium manganates are provided. Novel Na2/3Mn1−yFeyO2 (y = 0, 1/3 and 2/3) compounds with a P′3-type structure prepared from freeze-dried citrate precursors at 500 °C. A structural element is development of three-layer oxygen stacking contrary to well-known P2-type Na2/3MnO2 two-layer sequence. The effect Fe additives was examined by XRD powder diffraction TEM analysis. oxidation state distribution...