Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen-Doped Carbon Enables High-Performance Lithium-Sulfur Battery Cathodes
Here, we report a novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT) as a sulfur host which can strongly adsorb lithium polysulfides. The nitrogen functional groups of this composite enable effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to much improved electrochemical performance (1200 mAh/g after 200 cycles). The enhancement in adsorption can be attributed to chemical bonding of lithium ion with nitrogen functional groups in the MNCS/CNT framework. In addition, the micron-sized spherical structure of the material yields a high areal capacity (~6 mAh/cm2) with a high sulfur loading of ~5 mg/cm2, ideal for practical applications of Li-S batteries.
This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy (DOE) under Contract No. DE-EE0005475.
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