Eli Grigorova

Eli Grigorova
Bulgarian Academy of Sciences | BAS · Institute of General and Inorganic Chemistry

PhD

About

29
Publications
1,805
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488
Citations
Citations since 2016
5 Research Items
116 Citations
201620172018201920202021202205101520
201620172018201920202021202205101520
201620172018201920202021202205101520
201620172018201920202021202205101520
Additional affiliations
August 1999 - present
Bulgarian Academy of Sciences
Position
  • Professor (Associate)

Publications

Publications (29)
Article
Mixtures of corresponding metals with composition 95 wt% Mg2.05Ni0.7V0.3 and Mg2.1Ni0.7V0.3 and with addition of 5 wt% of activated carbon derived from apricot stones are prepared by ball milling under argon atmosphere. The received mixtures are tested for their hydrogen sorption characteristics at different temperatures. TEM characterization of th...
Article
Full-text available
Composites based on Mg2Ni with 5% activated carbon from apricot stones (ACAP) have been prepared by ball milling and subsequent annealing in hydrogen atmosphere. The purpose of the primary metal (Mg, Ni, and V) milling was to reduce the particle size and achieve a good contact between them, without forming intermetallic compounds. During hydriding/...
Article
Full-text available
Magnesium-based materials are promising as hydrogen storage media due to their high theoretical hydrogen absorption capacity, abundance and low price. The subject of this study are the hydrogen sorption characteristics of the composites 80 wt % MgH2-15 wt % Ni-5 wt % activated carbon (synthesized from polyolefin wax, a waste product of polyethylene...
Article
The absorption-desorption characteristics during prolonged cycling towards hydrogen of composite 95 wt% Mg- 5 wt% activated carbon (synthesized from polyolefin wax, a waste product of polyethylene production at low pressure- POW) obtained by ball milling under Ar atmosphere are investigated. Even at first few cycles of hydriding the 95 wt% Mg- 5 wt...
Article
Full-text available
The hydriding/dehydriding characteristics of 90 wt% MgH2–10 wt% MeSi2 (Me = Ti, Cr) composites, synthesized by ball milling under argon, were studied by Sievert’s type apparatus and by high-pressure differential scanning calorimetry (HPDSC). The composites have demonstrated similar absorption kinetics and capacity at temperature of 300 °C and a pre...
Article
Full-text available
High-pressure DSC was applied to study the hydriding and dehydriding behavior of Mg 95 mass%–C 5 mass% composites, synthesized by ball milling with two different kinds of carbon additives (activated carbon derived from apricot stones AS and from bean pods BP) and magnesium with different particle sizes. The composites containing finer magnesium exp...
Article
Full-text available
A 90 wt.% MgH2 - 10 wt.% V2O5 composite was obtained by ball milling of a mixture of magnesium hydride and vanadia for 60 min under argon. Hydrogen sorption properties of the composite were determined volumetrically with a Sieverts-type device. Absorption was studied at temperatures of 473 and 573 K and pressure of 1 MPa, while desorption was inves...
Article
Full-text available
Soft mechanochemically assisted reaction between CoOOH and LiOH.H2O at 400oC yields O3-layered LiCoO2 with nanometric particle sizes of 20–30 nm. The interaction of CoOOH with LiOH.H2O is monitored by DTA and TGA analysis. XRD powder and TEM analysis is used for structural and morphological characterization of the precursors and target LiCoO2. Soft...
Article
A comparison in the hydrogen sorption properties of mechanically activated magnesium composites with additive of 3d-metal containing compounds (Mg2Ni0.8Co0.2 and NiCo2O4) and activated carbon derived from agricultural by-products (ACAS) is accomplished. The presence of the additives used enhances significantly the hydriding reaction and increases t...
Article
The absorption–desorption characteristics towards hydrogen of obtained by ball milling under argon atmosphere magnesium based composites (containing respectively 95 wt% Mg and 5 wt% activated carbon (AC) derived from bean pods (BP), apricot stones (AS) and mixture of coal tar pitch and furfural (CTPF)), were investigated. Actually there is no subst...
Article
Novel Li1+xCo1-xO2 compositions were prepared by two synthesis methods: solid-state reaction between Li2O2 and Co3O4 under high-pressure and mechanochemical assisted reaction between CoOOH and LiOH.H2O. Variation of the Li-to-Co ratio in the precursor mixture from 1.0 to 2.0 results in the formation of Li1+xCo1-xO2 compositions with x0.12. The str...
Article
The absorption-desorption characteristics towards hydrogen of the composites 95wt.% Mg-5wt.% activated carbons derived from bean pods and apricot stones, obtained by ball milling in argon atmosphere were investigated. Hydriding of the composites was performed at temperatures 573 K and 473 K and pressure of 1 MPa and dehydriding - at T = 623 K and P...
Article
Magnesium-based composites of 75 wt% Mg — (10, 15, 20) wt% Mg2Ni0.7Co0.3 — (15, 10, 5) wt% C mechanically activated for 30 min under argon in a planetary mill, were obtained. Their absorption-desorption characteristics were investigated under a pressure P = 1 MPa and temperatures of 623, 573, 473, 423 and 373 K. Desorption was carried out at 623 K...
Article
Hydrogen absorption/desorption characteristics of the 95% Mg-5% activated carbon derived from apricot stones (ACA), 90% Mg-10% ACA and 85%-15% ACA, prepared by ball milling under argon, are studied. Hydriding process is proceeded at T = 573 K and 473 K and P = 1 MPa and dehydriding at T = 623 K and P = 0.15 MPa. The highest hydrogen absorption capa...
Article
Full-text available
The hydrogen absorption–desorption characteristics of composites containing 90 wt.% Mg or MgH2 and 10 wt.% of the intermetallic compound V0.855Ti0.095Fe0.05 obtained by mechanical alloying for 1 and 5 h in an inert medium were investigated. Absorption measurements were performed under a hydrogen pressure P = 1 MPa at temperatures of 623, 573, 523,...
Article
The effect of NiCo2O4 additives on the hydrogen absorption–desorption characteristics of 85wt% Mg–15wt% NiCo2O4 and 95wt% Mg–5wt% NiCo2O4 composites prepared by mechanical alloying in an inert atmosphere was investigated. The absorption of hydrogen was measured at temperatures of 573, 473, 423 and 373K and pressures of 1, 0.4 and 0.2MPa while the d...
Article
The hydrogen sorption properties of the nanocomposite 85wt.% Mg–15wt.% Mg2Ni0.8Co0.2 obtained by mechanical alloying in inert atmosphere were investigated. Absorption measurements were performed under a hydrogen pressure P=1MPa at temperartures ranging from 373 to 573K, while desorption studies proceeded at P=0.15MPa and temperatures of 573 and 553...
Article
The absorption-desorption properties of the nanocomposites 85 wt.% Mg-15 wt.% Mg2Ni1-xCox (x = 0.1, 0.2 and 0.3) prepared by ball milling in inert atmosphere have been studied. The hydriding proceeded at T = 573, 473, 423, 373 K and P = 1 MPa, while dehydriding was studied at T = 573 K and P = 0.15 MPa. A significant improvement of the hydriding ki...
Article
The hydrogen absorption-desorption characteristics of a 70% Mg, 15% Mg2Ni, 10%V and 5% Ti containing composite material, obtained by mechanical alloying in a planetary mill under argon, were studied. The experimental data on the kinetics of hydriding and dehydriding and on the absorption capacity values, established at various temperatures and hydr...
Article
The hydrogen absorption–desorption characteristics of a composite material containing 85wt.% Mg2Ni, 10wt.% V and 5wt.% Ti, obtained by mechanical alloying in a planetary mill under argon have been investigated. The experimental data on the kinetics of hydriding and dehydriding and the absorption capacity values established at various temperatures a...
Article
The hydrogenation at different temperatures and hydrogen pressures of the binary intermetallic compound CeNi was studied. A hydride with the composition CeNiH2.9(1) was obtained by hydriding the host alloy at 293 K and PH2=1 MPa. With increasing temperature of hydriding a reaction of hydrogenolysis of CeNi occurred with formation of a stable two-ph...
Article
The effect of additives on the hydrogen absorption–desorption properties of three series of composites (i) 85% Mg–15% Mg2Ni1-xMexMg2Ni1-xMex (Me=Fe, Co; x=0x=0, 0.1, 0.3); (ii) 75% Mg–15% Mg2NiMg2Ni–10% V and 75% Mg–15% Mg2NiMg2Ni–10% C and (iii) 90% Mg2NiMg2Ni–10% V and 90% Mg2NiMg2Ni–10% C obtained by mechanical alloying in different atmospheres...
Article
The hydrogen absorption–desorption characteristics of the nanocomposites 90wt.% Mg2Ni–10wt.% C (graphite) and 75wt.% Mg–15wt.% Mg2Ni–10wt.% C obtained by mechanical alloying have been investigated. Modification with graphite has been found to improve the hydriding kinetics of Mg2Ni at a temperature of 573K and below. The composite 75wt.% Mg–15wt.%...
Article
The hydrogen absorption–desorption characteristics of magnesium composites containing 10 and 15wt.% Mg2Ni1−xCox (x=0.1 and 0.3) obtained by mechanical alloying in an inert atmosphere have been investigated. A significant improvement of the hydriding kinetics of these composites has been established, the high absorption capacity being preserved even...
Article
The absorption–desorption characteristics of the nanocomposite 90 wt% Mg2Ni+10 wt% V obtained by mechanical alloying under argon or hydrogen atmosphere have been investigated. The effect of vanadium, the activation time and the gas medium during the milling on these characteristics have been shown. The absorption capacity of the sample activated fo...
Article
The combination of (i) the catalytic effects of Cr2O3, (ii) reactive mechanical grinding (RMG), and (iii) nanosize particles allow a huge improvement in the sorption properties of magnesium. For short milling duration, the absorption kinetics were already as good as that reported for nanocrystalline (Mg+Cr2O3) mixtures. The desorption process is al...
Article
The hydrogen sorption properties of the composites 85 wt.% Mg–15 wt.% Mg2Ni1−xFex (x=0, 0.1 and 0.3) prepared by high-energy ball milling were studied. It was shown that the presence of a Mg2Ni1−xFex additive significantly improved the kinetics of hydrogen absorption and desorption of magnesium, the absorption capacity remaining sufficiently high e...
Article
Full-text available
The absorption–desorption characteristics with respect to hydrogen of a magnesium-based nanocomposite obtained by high-energy ball milling have been investigated. The composite contains 5 wt.% (∼3at.%) Ti, 10 wt.% (∼5.5 at.%) V and 10 wt.% (∼5 at.%) Fe, of which the former two transition metals only form a binary hydride. It has been shown that at...

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Project
Special Issue for Submission of Materials- MDPI: “Metal and Intermetallic Hydrides for Hydrogen Storage". Deadline for manuscript submissions: 20 February 2022. https://www.mdpi.com/journal/materials/special_issues/metal_intermetallic_hydrides_hydrogen_storage