Three-Dimensional S/CeO₂/RGO Composites as Cathode Materials for Lithium⁻Sulfur Batteries

In this paper, the synthesis of the three-dimensional (3D) composite of spherical reduced graphene oxide (RGO) with uniformly distributed CeO₂ particles is reported. This synthesis is done via a facile and large-scalable spray-drying process, and the CeO₂/RGO materials are hydrothermally compounded with sulfur. The morphology, composition, structure, and electrochemical properties of the 3D S/CeO₂/RGO composite are studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), Raman spectra and X-ray photoelectron spectroscopy (XPS), etc. The electrochemical performance of the composites as electrodes for lithium⁻sulfur batteries is evaluated. The S/CeO₂/RGO composites deliver a high initial capacity of 1054 mAh g-1, and retain a reversible capacity of 792 mAh g-1 after 200 cycles at 0.1 C. Profiting from the combined effect of CeO₂ and RGO, the CeO₂/RGO materials effectively inhibit the dissolution of polysulfides, and the coating of spherical RGO improves the structural stability as well as conductivity.