A vapor-liquid-solid mechanism for in-situ deposition of ultra-small hollow MoS2 nanoparticles in N-doped carbon foam as an anode of lithium-ion batteries

Abstract

Although molybdenum disulfide (MoS2) has been nominated as a high theoretical capacity anode material for lithium-ion batteries (LIBs), intrinsic low electrical conductivity and massive volume expansion are significant obstacles to its application investment. Herein, a novel synthesis method has been developed to prepare the carbon foam/MoS2 (CF/MoS2) nanocomposite through an in-situ vapor-liquid-solid (VLS) mechanism to overcome its inherent disadvantages as a LIBs anode. A newfound MoS-polyHIPE, polyHIPE containing Mo and S precursors, was synthesized to provide the reaction confinement spaces. The in-situ reaction between sodium molybdate melt and gaseous sulfur products derived from decomposing the S precursor in the highly nanoporous polymer during low-temperature pyrolysis (700 °C) led to the precipitation of MoS2 nanoparticles in the carbon backbone. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman analysis demonstrated the formation of 1T/2H-MoS2. The TEM and HAADF-STEM micrographs revealed the ultra-small MoS2 nanoparticles with a hollow spherical shape well-distributed in the carbon framework. The unique composite structure of the homogeneously dispersed tiny nanoparticles in a nanoporous matrix caused fast diffusion of lithium ions, separated MoS2 nanoparticles without aggregation, and structural stability. The prepared composite exhibited a high specific capacity of 1051 mAh g−1 after 100 charge/discharge cycles. The composite also exhibited a significant specific capacity of 600 mAh g−1 at the high current density of 3C as an anode material for LIBs.