Synthesis and electrochemical performance of cubic Co-doped Li4Ti5O12 anode material for high-performance lithium-ion batteries

• Cubic Co-doped Li4Ti5O12 (LCTO) anode material was prepared via a high temperature solid-state reaction.
• Cells with the Cubic LCTO anode showed excellent cycle performances.
• Cyclic voltammetry and electrochemical impedance were employed to understand the cell performances.

Co-doped Li4Ti5O12 (LCTO) anode material for lithium-ion battery was synthesized via a mechanic ball-milling activation and high temperature solid state reaction using CoCO3, TiO2 and Li2CO3 as raw material. The structure, morphology and electrochemical properties of LCTO sample are characterized by X-ray diffraction (XRD), scanning electronic morphology (SEM), galvanostatic charge-discharge tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The LCTO is well crystallized as a spinel structure without any detectable impurity phase with the doping of Co. Thus, LCTO exhibits improving cycling stability and rate capability as anode material for lithium ion batteries, which delivered the initial specific capacity of 250, 222, 188, 180, 149 and 118 mAh g− 1 at 0.1, 0.2, 1.0, 2.0, 5.0 and 10.0 C rate in the voltage range of 0.5–3.0 V respectively, and discharge capacity of 200 mAh g− 1 after 100 cycles at 0.1 C. EIS results further show that the main reason for the improved electrochemical performance of LCTO is its reduced electrochemical impedance, which mainly due to the Co-doped modification leads to O vacancies then results in increase amount of embedded lithium in LCTO materials.