<scp>l</scp>-Cysteine-Assisted Synthesis of Layered MoS₂/Graphene Composites with Excellent Electrochemical Performances for Lithium Ion Batteries

TLDR

A facile l‑cysteine-assisted solution‑phase synthesis using sodium molybdate, graphene oxide, and l‑cysteine followed by 800 °C H₂/N₂ annealing produced layered MoS₂/graphene composites, which were characterized by XRD, SEM, EDS, and TEM. The MoS₂/graphene composites exhibit a three‑dimensional architecture and deliver an outstanding anode performance, achieving ~1100 mAh g⁻¹ at 100 mA g⁻¹ with excellent cycling stability and high‑rate capability due to their robust composite structure and synergistic MoS₂–graphene interactions.

Abstract

A facile process was developed to synthesize layered MoS2/graphene (MoS2/G) composites by an l-cysteine-assisted solution-phase method, in which sodium molybdate, as-prepared graphene oxide (GO), and l-cysteine were used as starting materials. As-prepared MoS2/G was then fabricated into layered MoS2/G composites after annealing in a H2/N2 atmosphere at 800 °C for 2 h. The samples were systematically investigated by X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. Electrochemical performances were evaluated in two-electrode cells versus metallic lithium. It is demonstrated that the obtained MoS2/G composites show three-dimensional architecture and excellent electrochemical performances as anode materials for Li-ion batteries. The MoS2/G composite with a Mo:C molar ratio of 1:2 exhibits the highest specific capacity of ∼1100 mAh/g at a current of 100 mA/g, as well as excellent cycling stability and high-rate capability. The superior electrochemical performances of MoS2/G composites as Li-ion battery anodes are attributed to their robust composite structure and the synergistic effects between layered MoS2 and graphene.