Unraveling the multiple effects of Li2ZrO3 coating on the structural and electrochemical performances of LiCoO2 as high-voltage cathode materials. (10th August 2016)

• Record Type: Journal Article
• Authors: Zhang, Jicheng; Gao, Rui; Sun, Limei; Zhang, Heng; Hu, Zhongbo; Liu, Xiangfeng
• Is Part Of: Electrochimica acta. Volume 209(2016)
• Page Start: 102
• Page End: 110
• Publication Date: 2016-08-10
• Subjects: Lithium-ion battery -- LiCoO2 -- surface coating -- Li2ZrO3 -- Synchronous lithiation strategy; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.05.066
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Highlights: LiCoO2 is coated by Li + -conductive Li2 ZrO3 by a synchronous lithiation strategy. Multiple effects of Li2 ZrO3 coating on high-voltage LiCoO2 are discovered. The synchronous lithiation coating strategy combines bulk doping and surface modifications. The interplanar spacing, layered structure stability and Li-ion diffusion coefficient are enhanced. The cycle performance, polarization, rate capability and thermo-stability have been significantly improved. Abstract: The poor cycle performance, low rate capability and thermo-instability limit the practical application of LiCoO2 as high-voltage cathode materials for lithium-ion batteries. Herein, we propose an integrated modification strategy which combines the advantages of elements doping, surface modifications and even the high Li + -diffusion of the coating layer. In this study, Li + -conductive Li2 ZrO3 has been successfully coated on the surface of LiCoO2 (Li2 ZrO3 @LCO) through a synchronous lithiation strategy and the multiple effects of Li2 ZrO3 coating on the structural and electrochemical performances of LiCoO2 as high-voltage cathode materials for Li-ion batteries have been discovered. In compared to bare LiCoO2, the cycle performance, polarization, rate capability and thermo-stability of Li2 ZrO3 @LZO have been significantly improved. Li2 ZrO3 @LCO shows a much higher capacity retention than bare LiCoO2 both at 25 °C (85.2% vs.32.6% at 5 C, 1 C = 200 mA g −1 ) and 55 °C (71.3% vs.13.9% at 5 C), and the specific capacity at 10 C has also been largely increased from 33.9 mAh g −1 to 103.4 mAh g −1 . The enhancement of the electrochemical performances can be largely attributed to the multiple effects of Li + -conductive Li2 ZrO3 coating: the alleviation of side reactions and transition metal dissolution, the enhancement of Li-ion diffusion coefficient and electronic conductivity, Zr 4+ migration and doping, the resulting interplanar spacing expansion and the improvement of the layered structure stability.