Synthesis and electrochemical performance of Li2VxMn1-xO3 positive electrode for lithium batteries

Lithium excess manganese oxide, namely, Li2MnO3 is under investigations to improve its electrochemical performance as the next generation high capacity electrode material. Partial substitution of Mn by another metal is one of the ways to influence the properties of Li2MnO3. In the present study, vanadium is used to partially substitute Mn in various ratios. Li2VxMn1-xO3 (x = 0.1, 0.2, 0.3 and 0.4) samples are prepared by sol-gel method using stoichiometric ratios weights of Mn(CH3COO)(2)center dot 4H(2)O, Li2CO3 and NH4VO3. The crystalline phases are identified by X-ray diffraction. The particles morphology is studied with a scanning electron microscope. Furthermore, impedance measurements (EIS) are applied using frequency range between 10(6) and 10(-2) Hz. The optimum EIS is obtained with for the Li2V0.3Mn0.7O3 cell. Cyclic voltammetric measurements are carried out for the lithium manganate materials between 0.01 and 4.5 V versus Li+ with scan rate 0.1 mV s(-1). Also, galvanostatic charging and discharging cycling of the cells are achieved with the same potentials windows using charging and discharging current intensity of 10 mA g(-1) between 1.5 and 4.5 V versus Li+. It is observed that Li/Li2V0.3Mn0.7O3 cell has higher specific discharge capacity, 227 mAh g(-1) rather than the other cells.