Electrochemical Behavior of Partially-Discharged Li x V2O5 Electrodes upon Interruption of Current

A mathematical diffusion model, which takes into account the electrochemical behavior of partially-discharged thin-layer electrodes made of intercalation materials upon interruption of circuit, is put forward. The applicability of the model is tested by the example of Li _x V₂O₅ films. According to theoretical calculations and experimental data, the equilibrium potential of the films studied depends practically linearly on the degree of intercalation with a slope of –0.8 V for intercalation degrees of 0.3–0.7. The chemical diffusion coefficient of lithium in the films is equal to 1.5 × 10^–11 cm²/s and changes insignificantly at these intercalation degrees.     

Lithium intercalation with phase transitions in model systems of electrode materials for lithium power sources

A comparison was made for Li⁺ chemical diffusion coefficients (D _Li) in graphite as calculated by mathematical models of Li⁺ intercalation under constant potential into semirestricted and restricted kinetic systems with mobile phase boundary and into a single-phase system. Close D _Li values were calculated by means of double-phase models. The double-phase model produces 6–7-fold D _Li coefficient as compared to the values of the single-phase model.     

Electrochemical Intercalation of Lithium Ions into Electrolytic Vanadium Pentoxide

The discharge of thin films of Li _x V₂O₅ is described by a mathematical diffusion model. The chemical diffusion coefficient for lithium ions, estimated with the model, is equal to (1.01–2.5) × 10^–11 cm²/s. As the film thickness increases, the discharge capacity at a current of 20 A/cm² tends to the calculated limiting of 3.12 C/cm². The optimum thickness of the film electrode calculated for a discharge current of 20 A/cm² is 33.4 m and agrees satisfactorily with the experimental value.     

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.     

Thin-Layer Electrolytic Molybdenum Oxydisulfides for Cathodes of Lithium Batteries

Electrolytic molybdenum oxydisulfides are synthesized out of aqueous molybdate solutions containing sulfur in the presence of ions of Ni²⁺ with the aim of applying them as materials for ballastless cathodes of thin-layer lithium batteries. The physicochemical and structural properties of the synthesized compounds are studied profilometrically and by methods of thermal and x-ray diffraction analyses, absorption IR spectroscopy, and atomic force microscopy. Specific discharge characteristics, the chemical diffusion coefficient of lithium ions, the interaction parameter of intercalated ions, and the repulsion energy of intercalated ions in the process of intercalation and deintercalation of lithium ions in the synthesized materials are determined.