Mulberry-like hollow rGO microspheres decorated with CoO nanoparticles as efficient polysulfides anchoring for Li-S batteries

Abstract

Lithium-sulfur batteries (LSB) became recently one of the most promising next-generation energy storage devices due to their high energy density and low cost. However, its large-scale commercial application is hindered by severe shuttle-effect and insulation of the sulfur. Herein, in order to overcome these disadvantages, mulberry-like three-dimensional hollow reduced graphene oxide microspheres modified with cobalt oxide nanoparticles (CoO/MGra) were designed as sulfur host. CoO/MGra possesses not only excellent electrical conductivity but also provides sufficiently large space for the storage of sulfur. The three-dimensional hollow structures can also significantly alleviate the volume expansion of sulfur during the cycling process. At the same time, the shuttle effect is suppressed due to the efficient chemical adsorption towards lithium polysulfide by CoO nanoparticles. As a result, excellent cycle stability (1010 mAh g−1 after 150 cycles at 0.2C) and outstanding rate performance (745 mAh g−1 at 3C) are achieved when using the S-CoO/MGra cathode.