Preparation and effects of F-doping on electrochemical properties of Li4Ti5O12 as anode material for Li-ion battery

Abstract

In this work, F-doped Li4Ti5O12 in the form of Li4Ti5O12-xFx (0 ≤ X ≤ 0.4) is successfully synthesized via a solid-state reaction between TiO2 (anatase), Li2CO3, and LiF. The synthesized powder is used as the anode in Li-ion batteries. X-ray diffraction (XRD) results show that the F−-doping does not change the spinel-type structure, and it has successfully doped into the crystal structure of Li4Ti5O12. The morphological and electrochemical characterization of synthesized powders is tested with the scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge-discharge techniques. Among the modified samples, Li4Ti5O11.7F0.3 delivers the highest capacity and cyclability. The Li4Ti5O11.7F0.3 (LTOF0.3) has a capacity of 139.7 and 134.7 mAh g−1 in the first and 100th cycles with 1 C, respectively. The retention of capacity after 100 cycles charge and discharge with 1 C for LTO and LTOF0.3 is 90.8 and 96.3%, respectively.