Enhancing the electrochemical performances of Li2S-based cathode through conductive interface design and addition of mixed conductive materials

•Polypyrrole coating is utilized for polysulfides immobilization.•Lithium sulfide is wrapped inside cathode from exposure.•Activation barrier and polysulfides shuttle are greatly suppressed.•Electrochemical performances of as-prepared cells are promoted. The significantly-high theoretical energy den...

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Bibliographic Details
Published in:Electrochimica acta 2021-11, Vol.396, p.139238, Article 139238
Main Authors: Liu, Hong, Zeng, Peng, Yu, Hao, Zhou, Xi, Li, Zhi, Chen, Manfang, Miao, Changqing, Chen, Gairong, Wu, Tianjing, Wang, Xianyou
Format: Article
Language:English
Subjects:
Battery cycles
Carbon nanotubes
Cathodes
Cycles
Decay rate
Electric cells
Electrode materials
Electron clouds
Flux density
Graphene
Li2S-based cathode
Lithium sulfur batteries
Lithium sulfur battery
Lithium-ion batteries
Oxidized graphene
Pi-electrons
Polypyrroles
Polysulfides
Polysulfides localization
PPy-coating
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Summary:•Polypyrrole coating is utilized for polysulfides immobilization.•Lithium sulfide is wrapped inside cathode from exposure.•Activation barrier and polysulfides shuttle are greatly suppressed.•Electrochemical performances of as-prepared cells are promoted. The significantly-high theoretical energy density and eco-sustainability of lithium sulfur batteries (LSBs) arouses a rapid surge of interest in recent years. However, some key issues of cathode, for instance, the polysulfides confinement, low ion/electrons transfer and etc., hinder the practical utilization of LSBs. Herein, such issues could be carefully handled by using the conductive polypyrrole as polysulfides wrapper. The polypyrrole with pyrrole rings can efficiently confine polysulfides inside cathode for redox. Meanwhile, the conductive polypyrrole with delocalized π-electron cloud can facilitate electrons transfer. Besides, the addition of carbon nanotube (CNT) and oxidized graphene (GO) can enhance the conductivity of cathode material. As a result, the Li2S/CNT/GO/PPy cathode delivers a cycling capacity of 525 mAh g−1 with a low-capacity decay rate of 0.065 % cycle−1 after 400 cycles. Therefore, the lithium-sulfur battery with Li2S-based and PPy-wrapped cathode could reasonably be counted as a potential alternative of long-cycling Li-ion cells. [Display omitted]
ISSN:0013-4686
1873-3859
DOI:10.1016/j.electacta.2021.139238