Li4Ti5O12/TiO2-SiO2 and Li4Ti5O12/SiO2 composites as an anode material for Li-ion batteries

摘要

The commercial electrode Li4Ti5O12 was modified with SiO2 and TiO2-SiO2. All samples were characterized by scanning electron microscope (SEM), particle size distribution (PSD), porous structure parameters (low-temperature N-2 sorption), galvanostatic charge-discharge test, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Appropriate amount of TiO2-SiO2 and SiO2 could effectively reduce the electrochemical polarization of Li4Ti5O12 and enhance electrochemical reaction kinetics of Li+ insertion/deinsertion. Moreover, Li4Ti5O12/TiO2-SiO2 provides a high rate capacity of 165 mAh g(-1) at the high current density of 0.5 C. To investigate cycle stability of the electrode materials at high current density, the measurements were directly carried out at 3 C. SEM images of the LTO/TiO2-SiO2, LTO, and LTO/SiO2 particles after galvanostatic charging/discharging show that they were coated by a uniform layer (the SEI layer).