A5005873335- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Catalytic Processes in Materials Science
- Catalysis and Oxidation Reactions
- Luminescence Properties of Advanced Materials
- Supercapacitor Materials and Fabrication
- Transition Metal Oxide Nanomaterials
- X-ray Diffraction in Crystallography
- Gas Sensing Nanomaterials and Sensors
- Magnetic Properties and Synthesis of Ferrites
- Multiferroics and related materials
- Crystal Structures and Properties
- Gold and Silver Nanoparticles Synthesis and Applications
- Extraction and Separation Processes
- Nanomaterials for catalytic reactions
- Ferroelectric and Piezoelectric Materials
- High-pressure geophysics and materials
- Zeolite Catalysis and Synthesis
- Iron oxide chemistry and applications
- nanoparticles nucleation surface interactions
- TiO2 Photocatalysis and Solar Cells
- Chemical Synthesis and Characterization
- Nanoparticles: synthesis and applications
- Acoustic Wave Resonator Technologies
- Magnetic properties of thin films
Bulgarian Academy of Sciences
2015-2024
Institute of General and Inorganic Chemistry
2013-2023
Institute of Mineralogy
2010-2020
Agrobioinstitute
2015
Sofia University "St. Kliment Ohridski"
1984-2015
Technical University of Sofia
2010
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...
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...
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...
Sodium-deficient nickel–manganese oxides with a layered type of structure are, nowadays, great interest as electrode materials for both lithium- and sodium-ion batteries since they are able to intercalate lithium sodium ions reversibly within broad concentration range. Herein, we report new data on the effects particle sizes electrolyte salt intercalation properties Na2/3Ni0.5Mn0.5O2 P3-type structure. The morphology has been varied by changing precursor used: from Na–Ni–Mn acetates mixed...
Layered lithium transition metal oxides with optimized nickel–manganese content are nowadays of primary interest as electrode materials for ion batteries, since they able to deliver a high capacity at low cost. Herein we report new class less expensive cathode materials, which comprise sodium-deficient cobalt–nickel–manganese NaxCo1/3Ni1/3Mn1/3O2 characterized layered structure and broad concentration range sodium solubility. obtained by thermal decomposition mixed acetate–oxalate...
Ceria is an important redox catalyst and its activity depends on the open Ce4+/Ce3+ sites, anion vacancies, surface OH groups ratio between them. We investigated effect of dehydroxylation evolution Ce4+ Lewis acidity oxidized ceria nanocubes, nanopolyhedra, nanorods. The {1 1 1} face not hydroxylated exposed after dehydration, adsorb CO weakly, forming linear carbonyls. hydroxyl coverage 0} consists terminal bridging hydroxyls, occurs 423 to 573 K by interaction these groups. produced sites...
An analytical method using silica supported silver nanoparticles as a novel sorbent for the enrichment and determination of inorganic mercury (iHg) in surface water samples has been developed. Silver (AgNPs) were synthesized by completely green procedure deposited onto amine functionalized submicrospheres (SiO2-NH2). The prepared nanocomposite material (SiO2/AgNPs) was characterized transmission electron microscopy, UV-vis spectroscopy, X-ray diffraction atomic force microscopy. sorption...
Reinforcement of aluminum and alloys with graphene has been intensively practiced by researchers in the past dozen years. The role Al4C3, which could be produced unintentionally or purposefully during composite production, was controversial until it found that nano-sized carbides were beneficial for strengthening composites. aluminum-graphene-nano-sized Al4C3 composites us using powder metallurgical method subsequent annealing. microstructure investigated light microscopy (LM), scanning...
Layered sodium transition metal oxides belong to electrode materials for sodium-ion batteries that combine, in a better way, high performance with environmental requirements. However, their cycling stability is still far from desirable. Herein, we demonstrate rational approach control the of sodium-deficient nickel manganese oxides, Na2/3Ni1/2Mn1/2O2, two- and three-layer stacking through Al substitution Al2O3 treatment. Na2/3Ni1/2Mn1/2O2 oxide displays limited ability accommodate aluminum...