Preparation of MoSe2 nanosheets/nitrogen-doped carbon nanotubes and their electrochemical energy storage properties

Abstract

Lithium-sulfur batteries can be used as excellent energy storage devices, but they still face some challenges in the practical application, such as the poor electrical conductivity of sulfur, the volume expansion of sulfur during the discharge process, and the dissolution of polysulfides. In this study, polypyrrole-coated molybdenum trioxide nanorods were used as templates for the simultaneous in-situ growth of MoSe2 nanosheets on the outer/inner sides of nitrogen-doped carbon nanotubes. When the MoSe2/N-carbon nanotubes (MoSe2/NC NTs) were used as sulfur carriers for lithium-sulfur battery, the large specific surface area of the N-carbon nanotubes facilitated the homogeneous loading of MoSe2 nanosheets and exposed more catalytically active sites of the MoSe2 nanosheets, increasing the contact area of electrolyte. In addition, the N-doped carbon nanotubes have excellent electrical conductivity, which greatly promotes the electrical conductivity of the cathode. The density functional theory calculations, adsorption experiments, and XPS results all confirm that the MoSe2/NC NTs are able to anchor lithium polysulfides through strong adsorption, thus effectively mitigating the shuttle effect of polysulfides. This study supplies a novel route for the preparation of sulfur host for advanced lithium-sulfur batteries.