Effects of sonication power on electrochemical performance of ZrO2-decorated LiMn2O4 cathode material for LIBs

Abstract

The LiMn2O4 (LMO) powder is decorated with ZrO2 (denoted as Zr@LMO) particles by using sonication-assisted sol–gel method. Different sonication powers (10, 30 and 50%) are used to disperse ZrO2 and the effects of ZrO2 distribution at LiMn2O4’s electrochemical performance are analysed. Scanning electron microscopy and energy dispersive spectroscopy analyses have been made on laminated samples. For the structural analyses of particles, X-ray diffractometer is used. Electrochemical performances of electrodes are tested with galvanostatic measurements, cyclic voltammograms and electrochemical impedance spectroscopy. The ZrO2 distribution ratio on the particle surfaces is improved by 10% with the increase of sonication power from 10 to 50%. Therefore, at 50% sonication power, lower charge transfer resistance and side reactions (Mn dissolution) are accomplished, which leads to 41 and 9% specific capacity increase compared to pure and the lowest sonication power, respectively. After 100 cycles at 0.1C, 93.2 mAh g–1 specific discharge capacity and 73.4% capacity retention are attained for ZrO2-decorated LMO at 50% sonication power. Furthermore, at 2C rate, the specific discharge capacity of the decorated sample at 50% sonication power is 59% higher than the pure LMO.