LiMn_2O_4/CNTs and LiNi_(0.5)Mn_(1.5)O_4/CNTs Nanocomposites as High-Performance Cathode Materials for Lithium-Ion Batteries

摘要

The demand of higher energy density and higher power capacity of lithium(Li)-ion secondary batteries has led to the search for electrode materials whose capacities and performance are better than those available today. Carbon nanotubes(CNTs), with their unique properties such as 1D tubular structure, high electrical and thermal conductivities, and extremely large surface area, have been used as materials to prepare cathodes for Li-ion batteries. The structure and morphology of CNTs were analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). The functional groups on the purified CNT surface such as –COOH, –OH were characterized by Fourier Transform infrared spectroscopy. The electrode materials were fabricated from LiMn2O4(LMO), doped spinel LiNi0.5Mn1.5O4, and purified CNTs via solid-state reaction. The structure and morphology of the electrode were characterized using XRD, SEM, and TEM. Finally, the efficiency of the electrode materials using CNTs was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy.