MoS2 nanosheets/graphitized porous carbon nanofiber composite: A dual-functional host for high-performance lithium-sulfur batteries

摘要

Lithium-sulfur batteries are considered to be one of the most promising next-generation energy storage systems due to their high theoretical specific capacity and high energy density. However, the inherent disadvantages of poor electrical conductivity, polysulfide shuttle effects, and volume expansion seriously hinder their practical commercial applications. In this study, we have successfully designed a three-dimensional free-standing composite cathode with MoS2 nanosheets growing on the surface of porous graphitized carbon nanofiber. The combination of porous carbon and MoS2 nanosheets can accommodate more sulfur active material, and the graphitized carbon can significantly improve the electrical conductivity of the overall electrode. More importantly, the MoS2 can further adsorb the intermediate polysulfide, preventing the loss of sulfur active material. As a result, the dual-functional composite cathode exhibits an initial reversible capacity of 1385 mA h g(-1) at 0.1C. When long-cycled at 1.0C, the capacity can be maintained at 594 mA h g(-1) after 500 cycles. When increasing the load of sulfur per unit area, the composite cathode electrodes continue to demonstrate excellent electrochemical performances. The results show that the dual-functional MoS2 Nanosheets/Graphitized Porous Carbon Nanofiber composite is an alternative cathode for future high-performance lithium-sulfur batteries. (C) 2019 Elsevier B.V. All rights reserved.