Delyana Marinova Manasieva

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

To make supercapattery devices feasible, there is an urgent need to find electrode materials that exhibit a hybrid mechanism of energy storage. Herein, we provide a first report on the capability of lithium manganese sulfates to be used as supercapattery materials at elevated temperatures. Two compositions are studied: monoclinic Li2Mn(SO4)2 and or...

To outline the role of dual-ion intercalation chemistry to reach sustainable energy storage, the present review aims to compare two types of batteries: widely accepted dual-ion batteries based on cationic and anionic co-intercalation versus newly emerged hybrid metal-ion batteries using the co-intercalation of cations only. Among different charge c...

Synthetic alluaudite-structure-type compounds have appeared to be promising cathode materials in electrochem-istry. Results from Rietveld refinement of the crystal structures of six representatives of this group with the general formula Na 2+2δ (Co 1-x Mn x) 2-δ (SO 4) 3 with chemical compositions falling within the range 0.12≤x≤0.52, have been rep...

This study aims to quantify the synergistic effect of Ni2+ and Mn2+ ions on the capacitive performance of oxide, hydroxide and phosphate electrodes in alkaline electrolytes. Three types of phases containing both nickel and manganese in a ratio of one-to-one were selected due to their stability in alkaline media: oxides with ilmenite and spinel stru...

Double sulfate salts of sodium and manganese, Na2Mn2(SO4)3, with an alluaudite-type of structure has been shown to intercalate Li⁺ ions reversibly, but the mechanism is still unclear. This study aims to examine the structure transformation of the alluaudite sodium manganese sulfate Na2Mn2(SO4)3 after Li⁺ intercalation by means of ex-situ transmissi...

The double sulfates with the general formula Na2M²⁺(SO4)2·nH2O (M = Mg, Mn, Co, Ni, Cu, Zn, n = 2 or 4) are being considered as materials for electrodes in sodium-based batteries or as precursors for such materials. These sulfates belong structurally to the blödite (n = 4) and kröhnkite (n = 2) family and the M cations considered in this work were...

Layered Mn5O8 is considered as low-cost and high-voltage electrode materials for storing Na⁺ ions in aqueous media. Herein we provide the first report on the intercalation of Li⁺ and Mg²⁺ ions into layered Mn5O8 in non-aqueous electrolytes. The layered oxide Mn5O8 is simply prepared by a thermal decomposition of freshly precipitated γ-MnOOH at 500...

The present work was devoted to study the catalytic activity of lanthanum and cerium oxides separately, deposited on γ-alumina in the reaction of decomposition of nitric oxide. The catalyst samples were prepared by the method of impregnation of γ-Al2O3 using solutions, containing nitrates of lanthanum and cerium. The prepared samples were calcined...

Based on different experimental methods—crystallization processes in aqueous solutions, infrared spectroscopy, single-crystal X-ray diffraction, electron paramagnetic resonance (EPR) and TG–DTA–DSC measurements—it has been established that copper ions are included in sodium cobalt sulfate up to about 18 mol%, thus forming limited solid solutions Na...

Alluaudite sulfates are predicted to be high-voltage electrodes for lithium- and sodium-ion batteries. Herein, we provide a first experimental evidence for operation of sodium cobalt-manganese sulfate, Na2+2δ(Co0.63Mn0.37)2-δ(SO4)3 at potentials higher than 4.0 V vs Li/Li+. This fact comes as a result of the reduced cationic deficiency, redox prope...

Double sodium transition metal sulfates combine in themselves unique intercalation properties with eco-compatible compositions – a specific feature that makes them attractive electrode materials for lithium and sodium ion batteries. Herein we examine the intercalation properties of novel double sodium nickel-manganese sulfate, Na2Ni1/2Mn1/2(SO4)2,...

In this contribution, we provide experimental results on the synthesis and some properties (structural, spectroscopic and thermal) of limited solid solutions Na2Ni1−xCux(SO4)2·4H2O (0 < x ≤ 0.17). Based on different experimental methods—vibrational spectroscopy (infrared and Raman), X-ray powder diffraction at ambient and elevated temperature, elec...

New structural, spectroscopic and thermal data on the formation and characterization of solid solutions containing cobalt blödite, Na2Co(SO4)2•4H2O, and magnesium blödite, Na2Mg(SO4)2•4H2O, are provided in this contribution. On the basis of the solubility data and X-ray powder diffraction it is found that both compounds form a continuous series of...

The present contribution provides new structural and spectroscopic data on the formation of solid solutions between hydrated and dehydrated sulfate salts of sodium-nickel and sodium-manganese in a whole concentration range: Na2Ni1-xMnx(SO4)2∙yH2O, 0 ≤ x ≤ 1.0. Using powder XRD, electron paramagnetic resonance spectroscopy (EPR), IR and Raman spectr...

Structural and thermal investigations of solid solutions Na2Zn1-xCux(SO4)2⋅4H2O (0 <x< 0.14) of a blödite-type structure are reported in the present paper. The replacement of the zinc ions by copper ones in the crystals of the blödite-type structure do not change considerably the lattice parameters and the volumes of the unit cells of the solid sol...

The solubility diagram of the Na2Zn(SO4)2-Na2Cu(SO4)2-H2O system at 25 ºC reveals that the copper ions are incorporated in the crystals of blödite-type structure, thus forming solid solutions of the type Na2Zn1-xCux(SO4)2.4H2O (0 < x < 0.14). However, the zinc cations do not accept the coordination environment of the copper ions in the strongly dis...

The solubility in the three-component systems Cs2SO4-CuSO4-H2O and Cs2SeO4-CuSeO4-H2O have been studied at 25 C. The experimental results show that double salts, Cs2Cu(SO4)2.6H2O and Cs2Cu(SeO4)2.4H2O, crystallize from the ternary solutions within large concentration ranges. Crystals of Cs2Cu(SeO4)2.6H2O were synthesized at somewhat lower temperatu...

The crystal structures and crystal chemistry of Cs2Mg(CrO4)2•6H2O and of twelve representatives along the Rb2Mg(Cr1-xSxO4)2•6H2O solid solution series, including the two endmembers, were studied using single crystal X-ray diffraction data. The Rb2Mg(Cr1-xSxO4)2•6H2O system seems to be the first structurally investigated continuous sulfate-chromate...

The alluaudite-type of structure is of huge research interest as an open matrix ensuring fast alkaline ion mobility, a property that could contribute to the development of novel electrode materials for rechargeable alkaline ion batteries. In this contribution, we provide new data on the formation of well-crystallized sodium manganese sulfates Na2+δ...

The solubility in the three-component (NH4)2SeO4–BeSeO4–H2O system is studied at 25 °C by the method of isothermal decrease of supersaturation. (NH4)2Be(SeO4)2·2H2O crystallizes from solutions containing 31.35 mass% beryllium selenate and 30.66 mass% ammonium selenate up to solutions containing 26.84 mass% beryllium selenate and 46.84 mass% ammoniu...

In this paper we report the crystal and molecular structure of the title compound, (NH4)2Be(SO4)2·2H2O, as determined by single-crystal X-ray diffraction and vibrational spectroscopy data.(NH4)2Be(SO4)2·2H2O crystallizes in the monoclinic space group P21/c (a = 11.448(2), b = 11.876(2), c = 7.439(1) Å, β = 96.64(1)°, V = 1004.6 Å3, Z = 4, R1 = 0.03...

A new compound, Rb4Be(SeO4)2(HSeO4)2·4H2O, crystallizes in a comparatively wide concentration range from mixed beryllium rubidium selenate solutions (from solutions containing 29.06 mass% beryllium selenate and 25.75 mass% rubidium selenate up to solutions containing 12.53 mass% beryllium selenate and 55.32 mass% rubidium selenate).Rb4Be(SeO4)2(HSe...

Infrared spectra of K2Ni(SeO4)2· 6H2O and (NH4)2Ni(SeO4) 2·6H2O containing SO42- ions and those of K2Ni(SO4)2·6H2O and K2Ni(SeO4)2·6H2O containing NH4+ ions are presented and discussed in the region of v3 and v1 of the sulfate ions and in the region of v4 of the NH4+ ions, respectively. The SO42- ions matrixisolated in the selenate matrices (approx...

Infrared spectra of K2Cu(SeO4)2·6H2O and (NH4)2Cu(SeO4)2·6H2O containing guest ions and those of K2Cu(SO4)2·6H2O and K2Cu(SeO4)2·6H2O containing guest ions are presented and discussed in the region of the stretching modes ν3 and ν1 of the sulfate ions and in the region of the asymmetric bending modes ν4 of the ions. The ions matrix-isolated in the...

Infrared spectra of compounds with kröhnkite-type infinite octahedral–tetrahedral chains, K2Me(CrO4)2·2H2O and Na2Me(SeO4)2·2H2O (Me = Mg, Co, Ni, Zn, Cd), as well as infrared spectra of the title double salts containing matrix-isolated SO42− guest ions are presented and discussed in the regions of the X–O stretching modes.The SO42− guest ions matr...

Infrared spectra of the title compounds with kröhnkite-type infinite octahedral–tetrahedral chains, K2Me(CrO4)2·2H2O (Me=Mg, Co, Ni, Zn, Cd), are presented in the regions of the uncoupled O–D stretching modes of matrix-isolated HDO molecules (isotopically dilute samples) and water librations. The strengths of the hydrogen bonds are discussed in ter...

Infrared spectra of K2Zn(SeO4)2·6H2O and (NH4)2Zn(SeO4)2·6H2O containing SO42− guest ions and those of K2Zn(SO4)2·6H2O and K2Zn(SeO4)2·6H2O containing NH4+ guest ions are presented and discussed in the region of the stretching modes ν3 and ν1 of the sulfate ions and in the region of asymmetric bending modes ν4 of the NH4+ ions, respectively. The SO...

Infrared spectra of K2Mg(SeO4)2·6H2O and (NH4)2Mg(SeO4)2·6H2O containing SO4²⁻ guest ions and those of K2Mg(SO4)2·6H2O and K2Mg(SeO4)2·6H2O containing NH4⁺ guest ions are presented and discussed in the region of the stretching modes ν3 and ν1 of the sulfate ions and in the region of the asymmetric bending modes ν4 of the NH4⁺ ions. The SO4²⁻ ions m...

Crystal structures of the isotypic compounds K2Co(CrO4)2·2H2O and K2Ni(CrO4)2·2H2O were refined from X-ray powder diffraction data (triclinic, space group P , Z = 1, a = 6.432(1)/6.425(1), b = 7.396(1)/7.355(1), c = 5.643(1)/5.619(1) Å, α = 96.61(1)/96.78(2), β = 106.64(1)/106.60(1), γ = 109.75(1)/109.84(1)°, V = 235.3/232.4 ų, Rwp = 8.22/9.27% fo...

The crystal structure of K2Zn(CrO4)2·2H2O was determined from single-crystal X-ray diffraction data (monoclinic, space group C2/c, a = 15.046(2), b = 5.664(1), c = 12.333(2) Å, β = 116.58(1)°, V = 939.9(3) Å3, Z = 4, R1 = 0.027 for 2405 Fo > 4σ(Fo) and 78 variables). The structure is built up from ZnO4(H2O)2 and CrO4 groups forming kröhnkite-type i...

The crystal structure of K2Cd(CrO4)2·2H2O was determined from single crystal X-ray diffraction data. It crystallizes triclinic (space group P , a = 5.896(1) Å, b = 6.446(1) Å, c = 7.596(1) Å, α = 109.09(1)°, β = 96.80(1)°, γ = 109.29(1)°, V = 249.1 Å3, Z = 1, R1 = 0.023 for 2672 Fo > 4σ(Fo) and 79 variables), isotypic with the respective Mg-analogu...

Some properties of different hydrates of beryllium selenate and sulfate as determined by means of TG, DTA, DSC, infrared spectroscopy and X-ray diffraction are reported. The crystal and molecular structure of BeSeO 4 .4H 2 O is solved by means of single crystal X-ray diffraction. The lattice parameters of BeSeO 4 .2H 2 O, BeSeO 4 and BeSO 4 .2H 2 O...

The isomorphic title series is investigated using single crystal X-ray diffraction and double matrix infrared spectroscopic techniques. The metal ion distribution at the two different metal sites (hexaformate-coordinated Me1 sites and mixed-coordinated Me2 sites) is found to exhibit a slight preference of Mn2+ ions to Me1 sites and Mg2+ ions to Me2...

The thermal dehydration of the title compounds was studied by TG, DTA and DSC methods and the enthalpies of dehydration were calculated (87.6 kJ mol–1 and 167.5 kJ mol–1 for the sulfate and selenate compound, respectively). The larger value of ΔHdeh of K2Be(SeO4)2·2H2O is due to the stronger hydrogen bonds formed in the selenate as compared to thos...

The metal ion distributions at the two metal sites (hexaformate-coordinated Me1 sites and mixed-coordinated Me2 sites) in the title mixed crystals as determined by single crystal X-ray diffraction and double matrix infrared spectroscopic methods are presented and discussed. The mixed formates are isostructural with the end compounds (space group P2...

The thermal dehydration of the title compounds was studied by TG, DTA and DSC methods and the enthalpies of dehydration were calculated (87.6 0 mol(-1) and 167.5 0 mol(-1) for the sulfate and selenate compound, respectively). The larger value of Delta H-deh of K2Be(SCO4)(2)(.)2H(2)O is due to the stronger hydrogen bonds formed in the selenate as co...

Infrared spectra of matrix-isolated SO42− guest ions in host chromate matrices – CaCrO4·2H2O, SrCrO4 and BaCrO4 are reported and discussed with respect to the SO stretching and OSO bending modes. When the larger CrO42− ions are replaced by the smaller SO42− ions the mean frequencies of the asymmetric stretching and bending modes (ν¯3 and ν¯4) as we...

Infrared spectra of matrix-isolated CrO42− guest ions in host sulfate matrices - CaSO4·2H2O, SrSO4, BaSO4 and PbSO4 are reported and discussed with respect to the Cr–O stretching and O–Cr–O bending modes. An adequate measure for the CrO42− guest ion distortion is the site group splitting Δνas and Δνmax (the difference between the highest and the lo...