Conductive Mesoporous Niobium Nitride Microspheres/Nitrogen-Doped Graphene Hybrid with Efficient Polysulfide Anchoring and Catalytic Conversion for High-Performance Lithium-Sulfur Batteries.

Author(s) Li, X.; Gao, B.; Huang, X.; Guo, Z.; Li, Q.; Zhang, X.; Chu, P.K.; Huo, K.
Journal ACS Appl Mater Interfaces
Date Published 2019 Jan 02

Lithium-sulfur (Li-S) batteries are promising next-generation energy storage devices because of the high energy density of 2600 Wh kg-1. 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) hybrid 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 Li2S 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-1 at 1 C (1 C = 1650 mA g-1), high rate capability of 739 mAh g-1 at 5 C, and excellent cycle stability with 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.

DOI 10.1021/acsami.8b17376
ISSN 1944-8252
Citation ACS Appl Mater Interfaces. 2019.

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