The results of the experiments on the development of positive thin-film electrodes for lithium-ion accumulators based on vanadium oxides are presented. The deposition modes and controlling methods of the structure and phase composition of the films, diagnostics methods of the structure and phase composition, and the results of the electrochemical tests of the positive electrodes are described.

Solutions of the problems of integrated absorption and amplitude-phase dispersion relations for transmission spectra in the range of isolated exciton resonances taking into account the interference of exciton-polariton waves based on the application of the causality principle to optical response functions and the limiting transition of these solutions for thick crystals are considered. It is shown that the results obtained are equivalent in the limit to the results of single-wave solution, which considers a wave with the least absorption. Generalization to the case of oblique incidence of light is performed.

A limiting transition between two solutions to the problem of total absorption in the region of exciton resonance in the presence of spatial dispersion (i.e., the solution considering a wave with lower absorption and the solution taking into account the exciton-polariton interference) is found. The crystal thicknesses at which the additional wave can be neglected are estimated. The dispersion relations for the bulk characteristics of dispersion and absorption are considered within the approximation obtained.

Expressions are obtained for the complex amplitude transmittance and reflectance of plane-parallel crystal plates in the excitonic spectral range under conditions when additional polaritonic waves associated with the effect of spatial dispersion are excited and when the presence of exciton-free layers on the surfaces of the crystal and multiple reflections in each of the layers is taken into account for different geometries of oblique incidence.

The analytic properties of the complex amplitude reflection and transmission coefficients of plane-parallel crystal plates in the exciton spectral region in the presence of additional waves are considered in a wide range of plate thicknesses and angles of incidence of light. It is shown that violations of the classical amplitude-phase Kramers-Kronig relations for the reflection and transmission can be described quantitatively by the contributions of the reflection and transmission zeros appearing due to the interference of ordinary and additional exciton-polariton waves. The decrease in the total absorption coefficient in the vicinity of the exciton resonance is also explained by the presence of transmission zeros in the upper half-plane of the complex frequency.

The reflectance and transmittance of light by plane-parallel crystal plates were found in the exciton-transition spectral region upon oblique incidence of light with polarization in which two transverse and one longitudinal normal exciton-polariton wave are excited. The reflection spectra calculated for a model crystal with the parameters of the CdSe crystal are analyzed for different thicknesses of the plates, angles of incidence, and damping constants. It is shown that accounting for additional exciton-polariton waves and multiple reflections of light inside the plate results in the possibility of an abrupt change in the phase (by more than 2π) in the vicinity of the exciton transition.