Journal
IONICS
Volume 20, Issue 5, Pages 635-643Publisher
SPRINGER HEIDELBERG
DOI: 10.1007/s11581-013-1044-5
Keywords
Polypyrrole-coated sulfur/MWCNT composite; EIS; Lithium-sulfur batteries; Kinetic properties; Cathode material
Ask authors/readers for more resources
Lithium-sulfur batteries have a poor cyclability and inferior rate capability due to the shuttle effect of lithium polysulfides. To solve these problems, a sulfur-coated MWCNT composite (S/MWCNT) was coated with conductive polypyrrole (PPy) to trap the polysulfides and facilitate charge and lithium ion transport. From the contact angle measurement, it is found that the PPy coating improves the wettability of the S/MWCNT composite. Compared with the bare S/MWCNT composite, the PPy-coated S/MWCNT composite cathode exhibited improved cycle stability and high-rate performance. A reversible discharge capacity of 671 mAh g(-1) was maintained after 50 cycles at 3 C for the PPy-coated composite. The effect of PPy coating on kinetic property was investigated by electrochemical impedance spectroscopy (EIS). The electrolyte resistance, surface film resistance, charge transfer resistance, lithium ion diffusion coefficient, and exchange current density were evaluated from the EIS measurements. The EIS results reveal that the PPy coating increases both Li ion diffusion into the cathode and exchange current density. The as-prepared PPy-coated S/MWCNT composite can be considered to be a promising candidate for high capacity and high-rate performance cathode material.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available