Li Xingxing, Gao Biao, Huang Xian, Guo Zhijun, Li Qingwei, Zhang Xuming, Chu Paul K, Huo Kaifu
The State Key Laboratory of Refractories and Metallurgy and Institute of Advanced Materials and Nanotechnology , Wuhan University of Science and Technology , Wuhan 430081 , China.
Department of Physics and Department of Materials Science and Engineering , City University of Hong Kong , Tat Chee Avenue , Kowloon, Hong Kong 999077 , China.
ACS Appl Mater Interfaces. 2019 Jan 23;11(3):2961-2969. doi: 10.1021/acsami.8b17376. Epub 2019 Jan 11.
Lithium-sulfur (Li-S) batteries are promising next-generation energy storage devices because of their high energy density of 2600 Wh kg. Efficient immobilization and fast conversion of soluble lithium polysulfide intermediates (LiPSs) are crucial to the electrochemical performance of Li-S batteries. Herein, we report a novel strategy to simultaneously achieve large capacity, high rate capability, and long cycle life by utilizing mesoporous niobium nitride microspheres/N-doped graphene nanosheets (NbN@NG) hybrids as multifunctional host materials for sulfur cathodes. The mesoporous NbN microspheres chemically immobilize LiPSs via Nb-S chemical bonding and catalytically promote conversion of LiPSs into insoluble LiS resulting in enhanced redox reaction kinetics. Moreover, the highly conductive NbN and N-doped graphene nanosheets provide rapid electron transport and consequently, the S/NbN@NG cathode demonstrates a large capacity of 948 mAh g at 1 C (1 C = 1650 mA g), high rate capability of 739 mAh g at 5 C, and excellent cycle stability with a capacity decay of 0.09% per cycle for over 400 cycles. The results described here provide insights into the design of multifunctional host materials for high-performance Li-S batteries.
锂硫（Li-S）电池因其2600 Wh kg的高能量密度而成为很有前景的下一代储能装置。高效固定和快速转化可溶性多硫化锂中间体（LiPSs）对Li-S电池的电化学性能至关重要。在此，我们报道了一种新策略，通过利用介孔氮化铌微球/N掺杂石墨烯纳米片（NbN@NG）杂化物作为硫阴极的多功能主体材料，同时实现大容量、高倍率性能和长循环寿命。介孔NbN微球通过Nb-S化学键合化学固定LiPSs，并催化促进LiPSs转化为不溶性Li₂S，从而增强氧化还原反应动力学。此外，高导电性的NbN和N掺杂石墨烯纳米片提供快速的电子传输，因此，S/NbN@NG阴极在1 C（1 C = 1650 mA g）下表现出948 mAh g的大容量，在5 C下具有739 mAh g的高倍率性能，以及出色的循环稳定性，在超过400次循环中每循环容量衰减0.09%。这里描述的结果为高性能Li-S电池多功能主体材料的设计提供了见解。
