SYNTHESIS AND INVESTIGATION OF ELECTROCHEMICAL CHARACTERISTICS OF OXIDE Li-CONDUCTIVE MATERIALS WITH SPINEL AND PEROSKITE STRUCTURES

Abstract

Lithium-ion batteries (LIBs) are widely used in electronic devices due to their numerous advantages, namely high energy density, high capacity, and long service life. One of the important components of a battery is the anode. In order to ensure high characteristics of LIB, the anode material must have high capacity, high ionic and electronic conductivities, and low cost. However, commonly used anode materials in lithium-ion batteries have a number of disadvantages. For example, a graphite-based anode is characterized by significant changes in volume during intercalation/deintercalation of lithium ions, high energy losses, and rapid deterioration of characteristics at high discharge/charge rates; Li4Ti5O12 have a low theoretical specific capacity, low electronic conductivity and low diffusion rate of lithium ions. Thus, the search for anode materials with high capacity and capability rate, as well as small volume change during lithium intercalation/deintercalation, remains an urgent task. A promising way may be the use of materials with intercalation pseudocapacitive behavior of charge accumulation, which occurs due to the intercalation of ions in tunnels or layers of active materials without a crystallographic phase transition. LixLa2/3-x/3TiO3 is well known as a superionic conductor with a high ionic conductivity σ ≈ 10–3 S/cm at room temperature. It crystallizes in a perovskite-type structure that consists of a framework of TiO6 octahedra stabilized by La atoms, and has nume­rous vacancies in the unoccupied positions 18d and 6a, that could participate in the stora­ge and motion of Li ions. Electrochemical characteristics of LixLa2/3-x/3TiO3 (x = 0.35 and 0.5) anode materials with a perovskite structure were investigated and compared with the electrochemical characteristics of Li4Ti5O12 with a layered spinel structure.