An Electrochemical Impedance Spectroscopic Study of CuF₂/MoO₃/C Cathode Composites

Authors

Yue-li SHI, School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221166, Jiangsu, China;
Nan WU, School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221166, Jiangsu, China;
Ming-fang SHEN, School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221166, Jiangsu, China;
Jia-qun DONG, School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221166, Jiangsu, China;
Quang-chao ZHUANG, School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221166, Jiangsu, China;Follow
Li JIANG, School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221166, Jiangsu, China;

Corresponding Author

Quang-chao ZHUANG(zqc209@126.com)

Abstract

Composite electrode of CuF₂/MoO₃/C was fabricated through high energy mechanical milling. The properties of CuF₂/MoO₃/C were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (TEM), galvanostatic charge-discharge measurements, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the grain sizes of CuF₂ and MoO₃ after milling were 200 ~ 300 nm, and the initial discharge capacity of CuF₂/MoO₃/C was 647 mAh?g-1 at room temperature and at a current density of 10 mA.g^-1. However, the capacity decayed rapidly in the next cycles. CV curves showed one reduction peak at 2.2 V in the first cycle and another one at 3.2 V in the following cycles. The Nyquist diagram of CuF₂/MoO₃/C electrode consisted of two semicircles and one line. During the discharge process, the high frequency semicircle (HFS) may be associated with not only the Li⁺ migration through the SEI film, but also contact resistance between the CuF₂/MoO₃/C composites and the current collector. The middle frequency semicircle (MFS) should be related to the Schottky contact between CuF₂ and conductive agents, which may be the important feature of such composites materials with big band gap. Besides the low frequency line may be related to the diffusion step. A very large value of charge transfer resistance for the CuF₂/MoO₃/C electrode may induce the rapid decay in capacity.

Graphical Abstract

Keywords

CuF2/MoO3/C composite electrode, conversion reactions, electrochemical impedance spectra, Schottky contact impedance

DOI Link

https://doi.org/10.61558/2993-074X.2108

Publication Date

2013-04-28

Online Available Date

2012-09-10

Revised Date

2012-08-30

Received Date

2012-07-16

Recommended Citation

Yue-li SHI, Nan WU, Ming-fang SHEN, Jia-qun DONG, Quang-chao ZHUANG, Li JIANG. An Electrochemical Impedance Spectroscopic Study of CuF₂/MoO₃/C Cathode Composites[J]. Journal of Electrochemistry, 2013 , 19(2): 155-163.
DOI: 10.61558/2993-074X.2108
Available at: https://jelectrochem.xmu.edu.cn/journal/vol19/iss2/6