Preparation and electrochemical properties of nanocrystalline LiB_xMn_2-xO₄ cathode particles for Li-ion batteries by ultrasonic spray pyrolysis method

Nanocrystalline LiB_xMn_2-xO₄ (x = 0.1-0.4) particles are prepared by ultrasonic spray pyrolysis using lithium nitrate, manganese nitrate and boric acid at 800 °C in an air atmosphere. The materials properties are characterized by X-ray diffraction, scanning electron microscopy, and atomic absorption spectroscopy. The electrochemical behaviors are investigated with cyclic voltammetry and galvanostatic techniques. The particle characterization studies show that nanocrystalline particles have spinel structure of submicron size with spherical morphology. All boron substituted lithium manganese oxide spinels show improved cycling performance. Among them, LiB_0.3Mn_1.7O₄ particles exhibit 92 mAh g^-1 discharge capacity and 82% capacity retention after 50 cycles at a 0.5 C rate. The higher degree of atomic ordering and the avoidance of the formation of a glass phase in LiB_xMn_2-xO₄ materials are responsible for the better electrochemical performance.