Synthesis and electrochemical properties of LiAl_(0.1)Mn_(1.9)O_4 by microwave-assisted sol-gel method

摘要

Aluminum-doped spinel-type LiMn_2O_4 cathode active materials have been synthesized by a microwave-assisted sol-gel method. The influence of synthesis conditions on the structural and electrochemical properties of LiAl_(0.1)Mn_(1.9)O_4 was investigated by thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and charge/discharge experiments. The powders resulting from the microwave-assisted sol-gel method with good crystallinity and cubic spinel shapes deliver an initial discharge capacity of 120mAh g~(-1), present excellent rate capability, and the Coulombic efficiency of it almost approaches 99 percent after 30 cycles. These advantages make it attractive particularly for a practical application. In addition, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to characterize the reactions of Li ion insertion into and extraction from LiAl_(0.1)Mn_(1.9)O_4 electrodes.