Improving the Cyclability and Rate Capability of Li4Ti5O12 Anode Material by Cu2+ and F− co‐Doping

Abstract

AbstractWe report a new Li4Ti5−xCuxO11.7F0.3 (X=0.1, 0.15, 0.2, 0.25, 0.3) anodic material for use in Li‐ion batteries. These modified Li4Ti5O12 (LTO) materials were prepared by solid‐state method and calcination at 800 °C. The Li4Ti4.75Cu0.25O11.7F0.3 (LTCu0.25OF0.3), among all samples, shows the best results in cyclability and rate ability. The LTCu0.25OF0.3 delivers discharge capacities of 188.8, 180, 169.7, 151.2, 116, and 93.6 mAh g−1 at 0.1, 0.2, 0.5, 1, 3, and 5C, respectively. The capacity retention of LTO, LTOF0.3, and LTCu0.25OF0.3 after 100 charge and discharge cycles at 1C is 90.8 %, 96.3 %, and 97.7 %, respectively. The enhancement in electrochemical performance of LTCu0.25OF0.3 is attributed to the lower polarization and charge transfer resistance (15.5 Ω) and higher Li+ diffusion coefficient (6.4×10−7 cm2 s−1) obtained by cyclic voltammetry (CV) and electrochemical‐impedance spectra (EIS) tests. This work indicates that Cu2+ and F− have a synergistic impact on the electrochemical properties of LTO.