Improve the structure and electrochemical performance of LiNi0.6Co0.2Mn0.2O2 cathode material by nano-Al2O3 ultrasonic coating
Journal
Journal of Alloys and Compounds
Journal Volume
611
Pages
135-141
Date Issued
2014
Author(s)
Abstract
The LiNi0.6Co0.2Mn0.2O2 powder was coated with nano-Al2O3 particles via ultrasonic coating, and its electrochemical performances were improved greatly. The X-ray diffraction, scanning electron microscopy, transmission electron microscope and energy dispersive spectroscopy were employed to research the structure variation, surface appearance and coating status. The results show that the nano-Al2O3 particles are successfully coated and the thickness of coating layer is about 20-25 nm. The XRD test results indicate that appropriate amount of Al2O3 coated is beneficial to form a better layered structure with smaller cation disorder. The charge-discharge results show that LiNi0.6Co0.2Mn0.2O 2 coated with Al2O3 of 1.0 wt.% has initial discharge capacity of 197.1 mA h g-1, initial coulombic efficiency of 91.2% at 0.2 C over 2.8-4.5 V and capacity retention of 91.0% much more than the pristine one of 82.9.0% after 30 cycles at 1 C. Especially, the rate capability of 1.0 wt.% Al2O3-coated sample is improved evidently, it shows a high discharge capacity of 153.5 mA h g-1 after 5 cycles under a 10 C rate, whereas the pristine one is only 126.3 mA h g -1 under the same conditions. The electrochemical impedance spectroscopy tests results also show that the impedance of LiNi 0.6Co0.2Mn0.2O2 is significantly reduced by Al2O3 coating during the cycling. © 2014 Published by Elsevier B.V.
SDGs
Type
journal article