Electrolytic Iron Sulfide Products in Lithium Batteries

A technology for electrolytic production of iron sulfide compounds applicable in thin-layer lithium batteries is developed. Physicochemical and structural properties and the surface morphology of compounds are studied by x-ray diffraction and thermal analyses, absorption IR spectroscopy, and atomic force microscopy. Specific discharge characteristics of compounds in thin-layer compact nonballast and paste electrodes of model lithium power sources are determined. The discharge capacity of compounds in thin layers weighing 1.0–7.5 mg cm^–2 galvanostatically cycled in electrolyte PC, DME, 1 M LiClO₄ at room temperature stays at 200–320 mA h g^–1 for 40–50 cycles.     

Electrolytic Nickel Oxides in the Electrodes of Lithium Secondary Batteries

A nickel oxide is synthesized for lithium secondary batteries using the suggested technology of electrolysis of aqueous solutions containing Ni²⁺. These oxides are studied by methods of x-ray structure analysis, thermal analysis, and atomic force microscopy in parallel with the determination of electrochemical characteristics. Electrolytic NiO has better specific discharge characteristics and cycle life as compared with other electrolytic nickel oxide compounds. It may be used as cathodic and anodic material in thin-layer lithium batteries.     

Electrolytic Synthesis of Binary Oxide Systems Based on Manganese(II) Oxide

Joint anodic deposition of manganese, cobalt, nickel, and chromium oxides, which form binary oxide systems, from two-component sulfate solutions of the constituent metals was studied under different electrolysis conditions.     

Study of electrolytic cobalt sulfide Co<Subscript>9</Subscript>S<Subscript>8</Subscript> as an electrode material in lithium accumulator prototypes

With the purpose to obtain a sulfide material for lithium and lithium-ionic thin-film batteries, cobalt sulfide Co₉S₈ was synthesized on an aluminum foil or stainless steel by electrolysis of aqueous solutions containing cobalt sulfate, sodium thiosulfate and sodium sulfide. The surface morphology of electrolytic Co₉S₈ is characterized by close packing of ball-like particles 8–12 μm in diameter, consisting of submicrometer structures 300–400 nm in size. It was found that e-Co₉S₈ electrodes exhibit stable behavior during 100 lithiation-delithiation cycles in a voltage range of 2.8–1.1 V, providing a discharge capacity of ～200 mAh/g. In a lithium cell with ethylene carbonate (EC)-dimethyl carbonate (DMC)-1M LiClO₄ electrolyte, a discharge capacity of the e-Co₉S₈-electrode was 250–450 mAh/g in a voltage range of 2.80–0.2 V. It was found that higher discharge capacities can be achieved for e-Co₉S₈-electrodes with a smaller active material mass.     

Electrolytic binary Co and Ni sulfides in electrodes of lithium and lithium-ion low—temperature batteries

Electrolytic binary e-Co, Ni-sulfides are synthesized on aluminum supports and studied in laboratory lithium and lithium-ion batteries with the electrolytes of ethylene carbonate—dimethyl carbonate—1 M LiClO₄ and propylene carbonate—dimethoxyethane—1 M LiClO₄. The discharge capacity of binary sulfides in laboratory cells is higher than in the case of the corresponding individual sulfides. A 2 V lithium-ion system with e-Co, Ni sulfide and LiMn₂O₄ as the negative and positive electrodes, accordingly, is suggested. The discharge capacity of a lithium-ion batteries exceeds 400 mA h/g of e-Co, Ni sulfide. A relationship is established between the surface morphology of the synthesized sulfides and their discharge characteristics.     

Changes in the energy distribution in mutant thylakoid membranes of pea with modified pigment content. II. Changes due to magnesium ions concentration

Low-temperature (77K) steady-state chlorophyll fluorescence emission spectra, room temperature fluorescence and light scattering of thylakoid membranes isolated from pea mutants were studied as a function of Mg2+ concentration. The mutants have modified pigment content and altered structural organization of the pigment-protein complexes, distinct surface electric properties and functions. The analysis of the 77K emission spectra revealed that Mg2+-depletion of the medium caused not only an increased energy flow toward photosystem I in all investigated membranes but also changes in the quenching of the fluorescence, most probably by internal conversion. The results indicated that the macroorganization of the photosynthetic apparatus of mutants at supramolecular level (distribution and segregation of two photosystems in thylakoid membranes) and at supermolecular level (stacking of photosystem II supercomplexes) required different Mg ion concentrations. The data confirmed that the segregation of photosystems and the stacking of thylakoid membranes are two distinct phenomena and elucidated some features of their mechanisms. The segregation is initiated by changes in the lateral microorganization of light harvesting complexes II, their migration (repulsion from photosystem I) and subsequent separation of the two photosystems. Most likely 3D aggregation and formation of macrodomains, containing only photosystem II antenna complexes, play a certain precursory role for the increasing degree of the membrane stacking and the energy coupling between the light harvesting complexes II and the core complexes of photosystem II in the frame of photosystem II supercomplexes.     

Electrolytic synthesis of FeS2 for thin-layer lithium battery

Purposeful synthesis of iron sulfide FeS₂ films for a lithium battery were purposefully synthesized on a 18N12Kh9T steel cathode from a solution containing Mohr’s salt and Na₂S₂O₃. Various aspects of synthesis were studied. Thin-film Fe-sulfide synthesis products were tested in a prototype lithium battery and also in a lithium-ion system. The synthesized electrolytic iron sulfide FeS₂ with a marcasite structure is capable of reversible electrochemical transformation with output of 390 mA h g^?1 in negative electrodes of the lithium-ion system with a LiMn₂O₄ counter electrode.     

Analysis of degradation of electrolytic Fe, Co, Ni sulfides and their graphitized analogs in lithium battery using impedance spectroscopy

Changes in parameters of complex-plane plots are analyzed for electrolytic Me _x S _y electrodes (Me = Fe, Co, Ni) and their graphitized analogs contacting electrolyte (ethylene carbonate, dimethyl carbonate, 1 M LiClO₄) in the case of degradation in a layout lithium battery at cycle 15. Impedance measurements in the high- and medium-frequency region of complex-plane plots revealed the key role of the surface solid-phase film and also of resistance of charge transfer through the sulfide material/electrolyte interface in degradation of Me _x S _y electrodes under cycling in the potential range of 2.80?0.02 V vs. Li/Li⁺. The activation energy is determined for processes of charge transfer through the electrode/electrolyte interface.     

Conversion efficiency of γ/β-MnO2 in composites with natural graphite and carbon nanotubes in a prototype lithium battery

Chemically synthesized manganese dioxide γ/β-MnO₂ was studied in composites with multi-walled carbon nanotubes and natural graphite of EUZ-M brand was studied in the redox reaction with lithium. It was shown that nanometer carbon electron-conducting filler is advantageous over the micrometer filler (EUZ-M) in the efficiency of influence exerted on power characteristics and cycling capacity of a prototype lithium battery with a cathode based on γ/β-MnO₂. The effective chemical diffusion coefficient of lithium ions in MnO₂ composites with multi-walled carbon nanotubes and EUZ-M was estimated and hodographs of electrodes based on γ/β-MnO₂ without a carbon additive and with EUZ-M, brought in contact with an electrolyte, were analyzed.