A composite material of uniformly dispersed sulfur on reduced graphene oxide: Aqueous one-pot synthesis, characterization and excellent performance as the cathode in rechargeable lithium-sulfur batteries

Abstract

Sulfur-reduced graphene oxide composite (SGC) materials with uniformly dispersed sulfur on reduced graphene oxide sheets have been prepared by a simple aqueous one-pot synthesis method, in which the formation of the composite is achieved through the simultaneous oxidation of sulfide and reduction of graphene oxide. The synthesis process has been tracked ex situ by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy, which both confirm that the majority of graphene oxide has been reduced during the synthesis reaction. The sulfur contents in the SGC, determined by thermogravimetry and elementary analysis, have been adjusted in the range from 20.9 to 72.5 wt.%. Scanning electron microscope (SEM) and transmission electron microscope (TEM) images reveal that most of the sulfur is uniformly dispersed on the reduced graphene oxide sheets, for which no sulfur in particulate form could be observed. The SGC materials have been tested as the cathode of rechargeable lithium-sulfur (Li-S) batteries, and demonstrated a high reversible capacity and good cycleability. The SGC-63.6%S can deliver a reversible capacity as high as 804 mA center dot h/g after 80 cycles of charge/discharge at a current density of 312 mA/g (ca. 0.186 C), and 440 mA center dot h/g after 500 cycles at 1250 mA/g (ca. 0.75 C).NSFC/HK-RGC Joint Research Scheme [N_HKUST609/09]; NSFC [20931160426

Sulfur–Graphene Nanostructured Cathodes via Ball-Milling for High-Performance Lithium–Sulfur Batteries

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Porous Graphene Materials for Energy Storage and Conversion Applications

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Boron-doped microporous nano carbon as cathode material for high-performance Li-S batteries

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