Литиевые электрохимические системы

A modern state of developments of lithium-ion batteries, as well as their main problems and the directions of their advancing are reviewed.

A number of Li_yNi_xCo_1-xO₂ compounds were synthesised by means of solid-state annealing. The synthesis conditions (the raw components, temperature, duration) were optimized so that phases with y > 0.97 were obtained suitable for making positive electrodes for lithium-ionic batteries. The charge-discharge characteristics of such Li_yNi_xCo_1-xO₂. electrodes were studied.

The processes of thermodestruction of lithium and cobalt oxides and their mixtures have been studied. The studies using the IR-spectroscopy as well thermogravimetric analysis showed, that during the initial stage of heating the mixtures of lithium and cobalt acetates the double salts form, and only then their thermodestruction proceeds.

With the aid of chronopotentiometry, voltammetry, and potentiostatic closure, the electrochemical characteristics of lithium intercalation to polyacrylonitrile carbon fiber was determined, namely, the capacitance, kinetic currents, lithium diffusion coefficient, autocharge currents. The study was made at 298 К in 1 M solutions of LiClO₄ in some mixed organic solvents (propylene carbonate – dimethoxyethane 7:3, propylene carbonate – diethyl carbonate 3:1).

The main roads of development in industrially useful solid polymer electrolytes (SPEs) are briefly reviewed. New SPEs based on acrylonitrile copolymers PBAN and PAN and lithium salts LiAsF₆, LiCF₃SO₃, LiCIO₄ have been obtained. The limits of salts solubility in polymer matrix PBAN were established. Ion solvation and ion association processes have been studied by IR spectroscopy. Conducting properties of SPEs were measured at 20-100°C.

The researches of behaviour of electrochemical systems organized by a method of direct contact of the Li-anode and a polymeric composite, including co-polymer polyacrylonitrile and organic semiconductor representing salt of thiopyrily with ClO₄^- and SnCl₆^2- anions are carried out. The basic electrochemical parameters of researched systems are determined.

New phases in the Li₂O-MnO₂ system were obtained, capable of introducing lithium electrochemically at potentials about 3 V and reversibly. They possess a stable capacity on the level 70-80 mA·hour/g. Due to their low cost, simplicity of synthesis, and high cycling ability, the oxides synthesized show promise as a cathodic material for lithium-ionic batteries.

Structural characteristics and morphology of the surface of dielectric deposits of V₂O₅, MnO₂, Co₂O₃ and binary oxide compounds V–Mn, Mn–Ni, Mn–Cr, Co–Ni and Co–Cr compounds were investigated. The probable mechanisms of their formation were considered.

The aim of this work was to explore the possibility of designing a valve-regulated nickel-cadmium KGL300P battery on the basis of the commercial lamellar-electrode KL300P battery with the use of a universal principle of compulsory oxygen pumping into the cadmium electrode's pores. The unwoven geotextile TU 8397-056-05283280-2002 linen of the Geocom A-200 brand can be used as a separator material in the design of such a battery.

A comparative study of electrochemical characteristics of alloy compositions hydrogensorbing type AB₅ – Nickel (as an activator, a conductive additive), depending on the size distribution of the components have been done. Results have determined that for simplification activation and increases of discharge capacity Metal-hydride an electrode the composition consisting of a powder hydrogensorbing of an alloy with the sizes of particles from 50 to 100 micrometers and the electroconductive additive with diameter of particles less 0,5 micrometers is optimum.