твёрдофазный синтез

Electrochemical Characteristics and Phase Composition of Lithium-Manganese Oxide Spinel with Excess Lithium Li_(1 + x)Mn₂O₄

The paper presents the results of the study of phase composition and electrochemical performance of lithium-manganese oxide spinel with excess lithium of nominal composition of Li1 + xMn2O4 obtained by solid-phase method. It was established that samples with x = 0.1 and 0.2 were composite materials with LiMn2O4 being the basic phase and Li2MnO3 being the impurity (3 and 7 mas.%, respectively) also comprising trace amounts of MnO2.

On determination of the mechanism of the processes proceeding at syntesis of electrode material LiFePO4

The methods for the synthesis of lithium iron phosphate LiFePO4 with olivine structure have been developed. New materials based on lithium iron phosphate, including doped with metals, the «LiFePO4 + carbon» composites obtained by pyrolysis of organic compounds have been synthesized. Crystallographic characterization of the synthesized materials was carried out; their electrochemical characteristics of the extraction and intercalation of lithium have been identified. A correlation between the crystallographic and electrochemical characteristics of the materials was found. It was confirmed that an effective way to improve the electrical conductivity of LiFePO4 is to create a carbon shell of the products of pyrolysis of organic compounds on the material's particles surface. A correlation of electrical conductivity and temperature of synthesis of the material was determined. The sequence of chemical interaction between precursors for the synthesis of LiFePO4 is defined; the mechanism of solid-phase interaction is described.

A study on LiMnyFe1-yPO4 as a cathode material for lithium-ion batteries

A series of solid phases (mixed lithium-iron-manganese phosphates) of the common formula LiMnyFe1-yPO4 (0 ≤ y ≤ 1) with a carbon coating on the particle surface was synthesized by mechanochemical activation with carbothermal reduction. The synthesized mixed phosphates were examined as promising cathode materials for lithium-ion batteries. The positive effect of replacement of a rather small fraction of iron by manganese is shown, which improves the electrochemical performance at the rates C/10–10C. The highest discharging capacity (above 160 mA·h/g at the C/10 rate, about 100 mA·h/g at the 10C rate) and cycling stability (the capacity decrease rate less than 0.05 mA·h/g per cycle at the 10 C rate) were established for the weakly doped cathode material LiMn0.05Fe0.95PO4.