Intrinsic Interfacial Property between High-Voltage LiNi_0.5Mn_1.5O₄ Cathode and Electrolyte

Authors

Li LI, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215125, China;University of science and technology of China, Nanoscience and Technology Institute, Suzhou, Jiangsu 215125, China;
Jing-jing XU, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215125, China;
Shao-jie HAN, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215125, China;
Wei LU, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215125, China;
Li-wei Chen, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215125, China;Follow

Corresponding Author

Li-wei Chen(lwchen2008@sinano.ac.cn)

Abstract

To obtain high energy density, developing high-voltage cathode materials is an effective approach. The cathode/electrolyte interface stability is the key factor for the cycle performance and safety performance of high-voltage lithium ion batteries. It is, therefore, of significant importance to study the stability of cathode/electrolyte interface. However, many reports have shown that at the cathode/electrolyte interface the cathodes were prepared by coating the mixture of active materials with a conductive additive and a binder on an Al current collector. The introduction of additives will interfere the surface morphology and component analyses, resulting in difficulty to acquire the intrinsic information at the cathode/electrolyte interface. In this paper, the LiNi_0.5Mn_1.5O₄ (LNMO) film electrodes were prepared via sol-gel method without using conductive additive and binder. The surface morphology and the intrinsic property of LNMO electrode/electrolyte interface during the charge/discharge process were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Electrochemical impedance spectroscopy (EIS). The results demonstrated that both solvents and LiPF₆ salt degraded during the charge/discharge process. The degradation of LiPF₆ mainly happened at the high-voltage charge process and the intermediate POF₃ was unstable which continued to be reacted during the discharge process. The degraded residues deposit on the surface of LNMO cathode to form a surface film and the compositions of the surface film varied with voltages during the electrochemical process.

Graphical Abstract

Keywords

high-voltage LiNi0.5Mn1.5O4 cathode material, cathode/electrolyte interface, intrinsic property, solid electrolyte interphase, oxidized decomposition of electrolyte, surface film

DOI Link

https://doi.org/10.13208/j.electrochem.160564

Publication Date

2016-12-28

Online Available Date

2016-07-29

Revised Date

2016-07-27

Received Date

2016-06-16

Recommended Citation

Li LI, Jing-jing XU, Shao-jie HAN, Wei LU, Li-wei Chen. Intrinsic Interfacial Property between High-Voltage LiNi_0.5Mn_1.5O₄ Cathode and Electrolyte[J]. Journal of Electrochemistry, 2016 , 22(6): 582-589.
DOI: 10.13208/j.electrochem.160564
Available at: https://jelectrochem.xmu.edu.cn/journal/vol22/iss6/6