1. A hydrogel-coated porous sulfur particle as volume-accommodable, conductivity-improved, and polysulfide-adsorptive cathode for lithium‑sulfur batteries.
- Author
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Liu, Jinyun, Chen, Yu, Zhang, Wen, Lin, Xirong, Zhang, Haikuo, Zhou, Ping, Wu, Yong, and Gu, Cuiping
- Subjects
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POLYSULFIDES , *LITHIUM sulfur batteries , *SULFUR , *CATHODES , *DENSITY functional theory , *PARTICLES - Abstract
Simultaneously achieving a high conductivity and a good volume-change accommodation for sulfur cathode in lithium‑sulfur batteries is highly required. Herein, we present a unique porous sulfur composite consisting of a porous sulfur particle coating with conductive hydrogel polypyrrole, which is prepared through a templated method. The pores inside the sulfur particles offer a good buffering space for the volume expansion of sulfur upon lithiation; while the external polypyrrole coating improves the conductivity and suppress the transfer of polysulfides. The porous sulfur@polypyrrole composite exhibits a capacity of about 900 mAh g−1 after cycling for 100 times at 0.12 C, along with a good Coulombic efficiency around 99.9%, which is much better than the polypyrrole-coated non-porous sulfur particles and pure sulfur particles. When cycled for 500 times, the capacity fading rate is as low as 0.09% per cycle. After three rounds of rate-performance measurements, the capacity retention of the sulfur@polypyrrole at different rates remain above 97%. The density functional theory calculations and electrochemical impedance spectra demonstrate a polysulfide-adsorptive and a stable electric transportation surface of the sulfur@polypyrrole composite, respectively. Unlabelled Image • A novel porous sulfur@hydrogel composite cathode is reported. • The Li-S batteries exhibit high electrochemical performance. • The cathodes enable accommodable volume-change and improved conductivity. • High proportion of capacitive contribution in overall capacity is achievable. • Density functional theory calculations demonstrate polysulfides adsorption. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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