Hrubiak A. Synthesis, structure and electrochemical properties of nanodispersed maghemite.

The work is devoted to research of general patterns influence of synthesis condi-tions on the structural, morphological characteristics and magnetic microstructure mesoporous maghemite and testing synthesized materials as a basis cathode composition of lithium power sources (LPS). The sol-gel citrate method to obtain of meso-porous maghemite, analysis of hydrolysis processes and stage complexation were developed. The dependence of morphology -Fe2O3, obtained by thermal decompo-sition of iron citrate xerogel, on the molar concentration of precursors and pH of the reaction medium was shown. The mechanism of formation mesoporous maghemite during the thermal decomposition of iron citrate hydrate gels was proposed. The morphology and size of particles depends on the competition of sintering processes and dispersion of material during the annealing. The defects of mesoporous maghe-mite influences its value of bandgap and magnetic structure. The dependence of the magnetic structure, in particular the phenomenon superparamagnetism on morpho-logical characteristics of material were traced. For the first time mesoporous maghe-mite received sol-gel citrate method was tested as a basis cathode compositions for LPS. The influence of the specific surface area on the value of specific capacity of LPS been set. The model of the LPS with cathode based on mesoporous maghemite was created and two phases of its work, namely adsorption of lithium on the surface of the interface cathode material/electrolyte and the intercalation of ions Li+ in the crystal structure of the material channels during the discharge was investigated. The coefficients of volume and percolation diffusion of ions Li+ in the structure of the cathode material were calculated. Thickness penetration of intercalating ions Li+ in the structure of the cathode is about 0.5 nm.