
Sergey V RyazantsevShenzhen MSU-BIT University · Faculty of Materials Science
Sergey V Ryazantsev
PhD
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40
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Publications (40)
The need for an alternative to lithium-ion batteries motivates the development of sodium-ion batteries, specifically focusing on biomass-derived hard carbon (HC) as anode material. However, the compositional variability in biomass leads to a lack of correlation between the microstructure and properties of HC. In this study, we used four simple carb...
Advances in sodium-ion batteries hugely rely on perfecting the performance of active electrode materials. In this paper, we offer a new NaVOPO 4 polymorph adopting a KTiOPO 4-type framework as a promising high-rate, low-strain and long-life positive electrode material for sodium-ion batteries. NaVOPO 4 is prepared via a facile hydrothermally-assist...
Redox flow batteries (RFBs) are a prospective energy storage platform to mitigate the discrepancy between barely adjustable energy production and fluctuating demand. The energy density and affordability of RFBs can be improved significantly through the transition from aqueous systems to non-aqueous (NAq) due to their wider electrochemical stability...
Effective solid-state electrolytes (SSEs) are now of major interest to battery society due to their improved safety and wide applicability. Although polymer-inorganic SSEs are very promising due to the beneficial...
Perovskite-type lanthanum iron oxide, LaFeO3, is a promising photocathode material that can achieve water splitting under visible light. However, the performance of this photoelectrode material is limited by significant electron-hole recombination. In this work, we explore different strategies to optimize the activity of a nanostructured porous LaF...
Preferential water transfer (PWT) is an important issue in vanadium flow batteries, which affects the cycling time. In this work, we propose a new way to control PWT by membrane modification. To assess PWT quantitatively, we developed an accurate method of water volume determination by optical monitoring of an anolyte. As result, we show that PWT f...
Polyanion compounds offer a playground for designing prospective electrode active materials for sodium-ion storage due to their structural diversity and chemical variety. Here, by combining a NaVPO4F composition and KTiOPO4-type framework via a low-temperature (e.g., 190 °C) ion-exchange synthesis approach, we develop a high-capacity and high-volta...
The demand for fast-charging metal-ion batteries underlines the importance of anodes that work at high currents with no risk of dendrite formation. NiBTA, a one-dimensional Ni-based polymer derived from benzenetetramine (BTA), is a recently proposed promising material for safe fast-charging batteries. However, its charge-discharge mechanisms remain...
The recently demonstrated possibility of high-voltage extraction of more than 2 Na ions per Na4MnV(PO4)3 formula unit is considered as a possible way to increase the specific energy of this material, which would open up prospects for its application in sodium-ion batteries. However, for the Na4MnV(PO4)3 material and for a wide group of related NASI...
The redox flow batteries (RFBs) are energy storage devices enabling to rationalize energy distribution from renewable sources. The lithium metal hybrid flow batteries (Li-HFBs) represent a very promising type of RFBs distinguished by improved energy and power density and simplified set-up. Unfortunately, the absence of a highly conductive and stabl...
In this work we have examined the radiation-induced synthetic chemistry occurring in an astrochemically important C2H2–CO system at the molecular level using a matrix isolation approach. The 1:1 C2H2∙∙∙CO intermolecular complex of linear structure was obtained in the solid low-temperature (5 K) noble gas matrices by deposition of the C2H2/CO/Ng (Ng...
Prussian blue analogues (PBAs) are commonly believed to reversibly insert divalent ions, such as calcium and magnesium, rendering them as perspective cathode materials for aqueous magnesium‐ion batteries. In this study, the occurrence of Mg²⁺ insertion into nanosized PBA materials is shown to be a misconception and conclusive evidence is provided f...
A new monoclinic α-polymorph of the Na2FePO4F fluoride-phosphate has been directly synthesized via a hydrothermal method for application in metal-ion batteries. The crystal structure of the as-prepared α-Na2FePO4F studied with powder X-ray and neutron diffraction (P21/c, a = 13.6753(10) Å, b = 5.2503(2) Å, c = 13.7202(8) Å, β = 120.230(4)°) demonst...
Hard carbon is the most prospective anode material for sodium-ion batteries with outstanding electrochemical performance. However, the type of reaction associated with charge storage is a subject of contentious deliberations within the scientific society. We examined the pseudocapacitive behavior of glucose-derived hard carbon with different porosi...
NASICON-structured cathode materials are considered as possible candidates for high-performance Na-ion batteries. Further increase of energy density of the Na3V2(PO4)3 may be achieved by substitution of the V cations by other transition metals. Here, we show that a family of Na3+xMnxV2-x(PO4)3 (0≤x≤1, Δx=0.2) cathode materials demonstrates remarkab...
X-radiolysis of the noble-gas matrices containing both H2O and CO was investigated at 5 K using infrared spectroscopy. It was found that formic acid molecule (HCOOH) could be produced from the matrix-isolated H2O⋯CO complexes, either directly as a result of irradiation or upon the subsequent annealing activating the trans-HOCO + H reaction. The for...
The rapid progress in mass-market applications of metal-ion batteries intensifies the development of economically feasible electrode materials based on earth-abundant elements. Here, we report on a record-breaking titanium-based positive electrode material, KTiPO4F, exhibiting a superior electrode potential of 3.6 V in a potassium-ion cell, which i...
Attempts to introduce vanadium doping into the olivine-structured LiMnPO4 cathode material for the Li-ion batteries resulted in the (y + z)PO4³⁻ → yVO4³⁻ + 4zOH⁻ (y < 0.17, z ≤ 0.1) co-substitution and the formation of the hydrotriphylite-type Li1−xMn1+x(PO4)1−y−z(VO4)y(OH)4z solid solutions. Their crystal structure and chemical composition were st...
Modern reconstructive and aesthetic surgery puts forward an ever expanding range of complex and competing biomedical, mechanical and handling requirements. These requirements could be satisfied through the creation of hierarchically structured tissue engineering objects, such as layered and hybrid materials. Collagen, hydroxyapatite (HAp) and ultra...
Hollandite‐type TiO2 with uniform submicron‐sized particles was prepared using the treatment of K1.2Ti8O16 by KBrO3 in an H2SO4 solution. The electrode material exhibited a 150 mAh g–1 reversible capacity with an average working potential of 1.75 V vs. Li/Li⁺. Phase transformations taking place during Li⁺ (de)intercalation were studied by means of...
Investigations of the low-temperature radiation-induced transformations in the C2H2–H2O system are relevant to the chemistry occurring in interstellar and cometary ices. In this work we applied a matrix isolation technique to study the radiation-driven evolution of this system at molecular level in order to get new mechanistic insight. The 1:1 C2H2...
We report an experimental and theoretical study on the complex of a noble-gas hydride HKrCCH with carbon dioxide. This species was prepared by the annealing-induced H + Kr + CCH···CO2 reaction in a krypton matrix, the CCH···CO2 complexes being produced by UV photolysis of propiolic acid (HCCCOOH). The HKr stretching mode of the HKrCCH···CO2 comple...
The radiation-induced transformations of acetylene, ethylene and ethane molecules under X-ray radiolysis in cryogenic media (noble gas matrices and neat hydrocarbon ices) at 5 K were characterized by FTIR spectroscopy. The radiation-chemical yields of decomposition of isolated hydrocarbon molecules were estimated in different solid noble gas matric...
We report on the complex of a noble-gas hydride HXeOH with carbon monoxide. This species is prepared via the annealing-induced H + Xe + OH···CO reaction in a xenon matrix, the OH···CO complexes being produced by VUV photolysis of the H2O···CO complexes. The H-Xe stretching mode of the HXeOH···CO complex absorbs at 1590.3 cm-1 and it is blue-shifted...
We report on the preparation and vibrational characterization of the C2H3⋯CO2 complex, the first example of a stable intermolecular complex involving vinyl radicals. This complex was prepared in Ar and Kr matrices using UV photolysis of propiolic acid (HC3OOH) and subsequent thermal mobilization of H atoms. This preparation procedure provides vinyl...
Conformers of carboxyl radical have been studied by IR spectroscopy in argon and nitrogen matrices. In an argon matrix, only the lower-energy conformer trans-HOCO is observed, whereas both cis and trans conformers are found for deuterated carboxyl radical DOCO. In a nitrogen matrix, both conformers of HOCO and DOCO isotopologues can be prepared, in...
Formyl radical HCO is an important reactive intermediate in combustion, atmospheric and extraterrestrial chemistry. Like in the case of other transients, the lack of knowledge of the absolute IR intensities limits the quantitative spectroscopic studies on this species. We report the first experimental determination of the absorption intensities for...
We report on the experimental and theoretical infrared spectrum of the C2H···CO2 complex. This complex was prepared by UV photochemistry of propiolic acid (HC3OOH) in argon and krypton matrices. The experimental bands of C2H in the C2H···CO2 complex are blue-shifted from those of C2H monomer. The calculations of the C2H···CO2 structures were perfor...
Vacuum ultraviolet (VUV, 130-170 nm) photochemistry of the H2OCO complex is studied by matrix-isolation infrared spectroscopy. The H2OCO complexes in Ne, Ar, Kr, and Xe matrices are generated by ultraviolet (UV, 193 and 250 nm) photolysis of formic acid (HCOOH). VUV photolysis of the H2OCO complexes is found to lead to the formation of the OHCO rad...
The radiation-induced transformations of small molecules at low temperatures play an important role in the interstellar, planetary and atmospheric chemistry. This work presents a review of our recent model studies on the radiation chemistry of relevant molecules in solid noble gas (Ng) matrices, including some preliminary new results. Among the tri...
The effect of X-ray irradiation on the isolated formic acid molecules (HCOOH) in solid noble gas matrices (Xe, Kr, Ar, and Ne) at very low temperatures (6 K) was first studied by FTIR spectroscopy. Carbon oxides (CO and CO2) and hydrocarboxyl radicals (HOCO) have been detected as the principal degradation products. The formation of HOCO radicals re...
The radiation-induced transformations occurring upon X-ray irradiation of the solid CO2/H2O/Ng systems (Ng = Ar, Kr, Xe) at 8 - 10 K and subsequent annealing up to 45 K were studied by FTIR spectroscopy. The IR spectra of deposited matrices revealed the presence of isolated monomers, dimers and intermolecular H2O…CO2 complexes. Irradiation resulted...
The photo-induced transformations of HXeSH and HXeH under the action of IR and visible light have been studied using FTIR spectroscopy. The xenon hydrides were produced by the X-ray induced decomposition of H2S and its isotopomers in a solid xenon matrix at 7.5 K followed by thermal annealing at the temperatures up to 45 K. Selective IR-induced pho...