Role of calcination atmosphere in vanadium doped Li 4 Ti 5 O 12 for lithium ion battery anode material

Abstract Li4Ti5O12 (LTO) with enhanced properties can replace the conventional carbonaceous anode material of lithium ion battery. Vanadium doped LTO (Li4Ti5-xVxO12, x = 0, 0.05, 0.1, 0.15) materials are synthesized by sol-gel process followed by calcination of dried gel in air and argon atmosphere. No additional phase corresponding V is indicated in XRD patterns. Calcination in argon reduces the particle size of Li4Ti5-xVxO12 while V doping reduces particle size distribution. XPS reveals that Ti4+ get reduced to Ti3+ only in argon calcined Li4Ti5-xVxO12 which is enhanced by V doping. Electrochemical impedance spectroscopy confirms that compared to LTO, lithium ion diffusion coefficient of air and argon calcined Li4Ti4.85V0.15O12 is approximately two and three times higher. Argon calcined Li4Ti4.9V0.1O12 shows highest charge-discharge capacities at almost all C-rates (0.1 to 5C; 1C = 175mAg−1). Electronic conductivity of argon calcined Li4Ti4.9V0.1O12 is 1.7 × 10−2 S cm−1 which is three orders higher than that of LTO.