Reduced Graphene Oxide/Sulfur Composite Cathode Material for Lithium Sulfur Batteries

Reduced graphene oxide/sulfur composite cathode material was prepared by simple melting method, while reduced graphene oxide was obtained by high temperature reduction. The structure and composition of the reduced graphene oxide/sulfur composite were characterized with X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectra, scanning electron microscopy, and nitrogen adsorption isotherms. It is shown that reduced graphene oxide/sulfur composite was prepared successfully and reduced graphene oxide is layered mesoporous structure. This structure of reduced graphene oxide has large specific surface area (328.2 m²/g) which could provide space for high-load sulfur, and mesopores could relieve the shuttle effect during charge and discharge. The electrochemical performance is evaluated by cyclic voltammetry and rate charge-discharge. The composite cathode material shows high and stable specific capacity up to 684 mAh/g after 100 cycles at the rate of 0.5 C, representing a promising cathode material for rechargeable lithium batteries with high energy density.