Electrochemical performance of V-doped spinel Li4Ti5O12/C composite anode in Li-half and Li4Ti5O12/LiFePO4-full cell

This work reports the preparation of a V-doped Li4Ti5O12/C (donated as V-doped LTO/C) composite material, applying a solid-state method. Both metal doping and carbon coating are applied on the Li4Ti5O12 material, enhancing its rate capability and cycle stability. Furan polymer is used as a carbon source, and vanadium (V) is selected as a dopant. The properties of the materials are examined by X-ray diffraction (XRD), micro-Raman, scanning electron microscopy (SEM), high-resolution transmission microscopy (HR-TEM), the AC impedance method, and the galvanostatic charge/discharge method. For comparison, Li4Ti5O12/C composite materials with and without V doping are also examined. The Li4T4.90V0.10O12/C composite material achieves discharge capacities of 165.59 and 76.76 mAh g(-1) at a 0.2/1C and 0.2/20C rate, respectively. A Li4Ti5O12/LiFePO4 full cell (LTO capacity-limited) is constructed and investigated. The full cell exhibits discharge capacities of 181, 178, 167, 142, 110, and 78 mAh g(-1) at 0.2, 0.5, 1, 3, 5, and 10C, respectively. We determine that the Li4Ti4.95V0.05O12/C composite anode is an outstanding candidate for application in high-power Li-ion batteries. (C) 2014 Elsevier B.V. All rights reserved.