Electrochemical lithium storage of Li4Ti5O12/NiO nanocomposites for high-performance lithium-ion battery anodes

Abstract

Li4Ti5O12/NiO (LTO/NiO) composites with various NiO contents were prepared successfully as anode materials for high-performance lithium-ion battery. The preparation procedure consisted of high-energy ball milling, high-temperature calcination, and solution coating in succession. Several techniques such as X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge-discharge, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were applied to fully investigate the micromorphology, composition structure, and electrochemical performances of the LTO/NiO composites. It was found that all the LTO/NiO composites showed higher discharge capacity than the pure LTO anode within the representative 20 cycles. The LTO/5 wt.% NiO, which had the largest specific surface area of 2.1229 m(2) g(-1) among all the LTO/NiO composites, delivered a capacity of 203 mAh g(-1) in a voltage window of 0.5-3.0 V at 1 C rate and retained a capacity of 176 mAh g(-1) after 100 cycles. The CV and EIS analysis indicated that the charge/discharge processes of LTO/NiO composites included the Li+ diffusion into or out of LTO phase and the redox reaction of NiO phase. The results demonstrate that the surface modification of LTO with small amounts of NiO nanoparticles can decrease the overall charge transfer resistance by forming in situ the electron-conductive Ni, leading to the improved electrochemical behavior of the composites.