Chitosan-Induced Synthesis of Hierarchical Flower Ridge-like MoS2/N-Doped Carbon Composites with Enhanced Lithium Storage

Abstract

Continuous hierarchical MoS2/C micro/nanostructured composite with strong structural stability and efficient lithium ion and electron transport channels is an urgent need for its successful application in lithium ion battery anode materials. In this study, continuous hierarchical flower ridge-like MoS2/N-doped carbon micro/nanocomposite (MoS2/NC) was first synthesized through a simple chitosan-induced one-pot hydrothermal and postsintering method. The amino-containing chitosan is demonstrated to be important not only in nitrogen-doped carbon source, soft template, and surfactant but also in controlling the interlayer distance between adjacent MoS2 layers. The detailed hierarchical structure, phase characteristics, the number of MoS2 stacked layers, and interlayer distance were characterized using a scanning electron microscope, transmission electron microscope, X-ray diffraction, and so forth. It reveals that the interconnected nanoflowers composed of few-layer MoS2 (≤3 layers) nanoflakes with an expanded interlayer distance vertically grow on two-dimensional N-doped carbon nanosheets in the MoS2/NC composite. When examined as anode of lithium ion batteries, this unique hierarchical MoS2/NC micro/nanostructure shows better electrochemical performance. The electrode delivers a reversible capacity of 904.7 mA h g-1 at 200 mA g-1 after 100 cycles, outstanding cycle stability at high rates (742, 686, 534 mA h g-1 at 500, 1000, 2000 mA g-1 after 400 cycles, respectively) and superior rate performance. The above synthesis strategy is a good choice for constructing other hierarchical transition-metal disulfides or oxides and carbon micro/nanostructures to improve their electrochemical performance.