ИСТИНА

At the moment, olivine-structured complex phosphates of lithium and transitional metals are considered as one of most promising cathode materials for li-ion batteries; LiFePO4 is actually most studied. Besides advantages, such as high theoretical capacity, low cost and excellent cyclability, LiFePO4 has serious drawbacks. One of them – low working potential in comparison with other materials (3.4V vs. Li/Li+). In other side, materials with higher potential such as LiCoPO4, LiMnPO4, LiNiPO4 cannot be used in li-ion batteries at the moment, because of low achievable capacity and poor cycle life. Usage of solid solution from the specified materials, for example LiFe1-xMxPO4, gives opportunity to combine high working potential, structure stability and good cyclability. For the perfect electrochemical performance and cycle life it is important to obtain material with definite morphology and size of particles. In this work were performed different types of solvothermal synthesis and reaction mechanism study of LiMn0.5Fe0.5PO4 cathode material. All samples of LiMn0.5Fe0.5PO4 were synthesized via hydrothermal and solvothermal route. For solvothermal synthesis as solvents ethanol, ethylene glycol, polyethylene glycol were used. Mechanism of phase nucleation and crystal growth in hydro- and solvothermal conditions were investigated. Particles obtained using by hydrothermal and solvothermal methods have plate-like morphology with 50-200 nm thickness. Samples were studied by X-ray diffraction, scanning electronic microscopy (SEM), elemental analysis (EDX). Electrochemical properties of the specified materials are evaluated by galvanostatic and potentiostatic methods. Values of reversible capacity for all materials are 140-150 mAh/g at C/20 discharge rate. The work was supported with the RFBR grants (14-03-31473, 14-29-04064).