期刊
CHEMICAL ENGINEERING JOURNAL
卷 411, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2021.128504
关键词
Lithium-sulfur battery; Nb-based inorganics; Redox kinetics; Nanospace confinement
资金
- National Natural Science Foundation of China [22078100, 21878091, 22008073]
- Fundamental Research Funds for the Central Universities
This study introduces Nb2O5 and NbC into hollow carbon nanospheres to enhance the catalytic performance in Li-S batteries. The optimized HCN@NbC/S cathode exhibits outstanding reversible capacity and cycling performance with high rate capability.
The sluggish redox kinetics and shuttling behaviors of intermediate polysulfides are dominant obstacles that hamper the practical applications of Li-S battery. In this work, two types of niobium (Nb)-based inorganics, semiconductive Nb2O5 and conductive NbC, are implanted into hollow carbon nanospheres (HCN) hosts, which can realize the cooperativity of nanospace confinement and high-efficiency catalytic Nb-based inorganics for high-rate Li-S batteries. The initial HCN have adequate hollow space achieving high sulfur loading, interpenetrated mesoporous channels for rapid ion transfer, and developed microporous carbon framework blocking the polysulfides shuttling. While Nb-based inorganics are uniformly located in the mesoporous channels, they can accelerate the conversion kinetics of the polysulfides by strong chemical interaction and high catalytic effect. Furthermore, we demonstrate that the conductive NbC performs much better catalytic activity than the Nb2O5, with significantly improved redox kinetic and cycling performance. The optimized HCN@NbC/S cathode delivers a preeminent reversible capacity of 500 mAh g(-1) with a low capacity decay of 0.05% per cycle over 800 cycles at 3 C and a high rate capacity of 752 mAh g(-1) under a high current density of 5 C. This work provides a novel strategy to construct desirable multifunctional host favoring cooperative polysulfides interactions via rational integration of physical confinement and high-effective catalytic inorganics for long-cycling stable sulfur cathode.
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