LaF sub(3)-coated Li[Li sub(0.2)Mn sub(0.56)Ni sub(0.16)Co sub(0.08)]O sub(2) as cathode material with improved electrochemical performance for lithium ion batteries

• Published in: RSC advances 2015-06, Vol.5 (63), p.50859-50864
• Main Authors: Xie, Qingliang, Hu, Zhibiao, Zhao, Chenhao, Zhang, Shuirong, Liu, Kaiyu
• Format: Article
• Language: English
• Subjects: Cathodes; Coating; Electrochemical analysis; Electrochemical impedance spectroscopy; Lithium-ion batteries; Microspheres; Morphology; Scanning electron microscopy
• ISSN: 2046-2069
• DOI: 10.1039/c5ra06243h

In this article, the pristine Li-rich layered oxide Li[Li sub(0.2)Mn sub(0.56)Ni sub(0.16)Co sub(0.08)]O sub(2) porous microspheres have been successfully synthesized using a urea combustion method and then coated with 1 wt% LaF sub(3) via a facile chemical precipitation route. The structures and morphologies of both pristine and LaF sub(3) coated Li sub(1.2)Mn sub(0.54)Ni sub(0.16)Co sub(0.08)O sub(2) were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HR-TEM). The results reveal that the obtained particles possesses the morphology of porous microspheres and a LaF sub(3) layer with a thickness of 5-8 nm coated on the surface of the Li[Li sub(0.2)Mn sub(0.56)Ni sub(0.16)Co sub(0.08)]O sub(2) particles. As lithium ion battery cathodes, the LaF sub(3) coated sample, compared with the pristine one, has shown a significantly improved electrochemical performance; the initial coulombic efficiency improves from 75.36% to 80.01% and the rate compatibility increased from 57.4 mA h g super(-1) to an extremely high capacity of 153.5 mA h g super(-1) at 5 C. Decreased electrochemical impedance spectroscopy (EIS) reveals that the enhanced electrochemical performance of the surface coating was attributed to the lower charge transfer resistance of the sample.