Ni and F co-modification to enhance the electrochemical properties of Li4Ti5O12 anode materials for lithium-ion batteries

Abstract

As a negative electrode material, the main drawbacks of Li4Ti5O12 (LTO) are its low electric conductivity and poor Li-ion diffusion coefficient. Fortunately, elements modification to address these problems is an effective method. Herein, we firstly report Ni and F co-modified LTO material which is synthesized via a solid-state reaction. Powder X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy were conducted to investigate the structure and morphology. Afterwards, we surprisingly find that Ni and F co-modification can reduce the overall charge transfer resistance of LTO for part of Ti4+ converts into Ti3+ and Ni2+ ions supply the charge carriers. When test in battery, a superior discharge capacity of 236.1 mAh g−1 at 0.036 A g−1 is obtained, much higher than that of pristine LTO (196.9 mAh g−1). Furthermore, it still retains a discharge capacity of 174.6 mAh g−1 after 200 cycles at 0.18 A g−1 and exhibits an excellent rate performance.