A 3D Graphene/WO3 nanowire composite with enhanced capture and polysulfides conversion catalysis for high-performance Li–S batteries

Abstract

The lithium-sulfur (Li–S) batteries have been deemed to be one of the most promising systems for next-generation energy storage devices due to their high theoretical energy density of 2600 Wh kg−1, cost-effectiveness, earth abundance, and environmental friendliness. However, its commercialization process is challenged by several issues, such as the non-conductive sulfur cathode material itself and the polysulfide shuttle effect, as well as sluggish redox reaction kinetics. Herein, we designed a three-dimensional hierarchical structure of reduced graphene-tungsten oxide skeleton as a highly conductive and stable sulfur host material in Li–S battery. Based on various spectroscopic techniques, and In-situ electrochemical studies together with computational methods, it was confirmed that rGO@WO3 can catalyze the polysulfide conversion for improving Li–S battery performance. The constructed 3D rGO@WO3@S cathode delivers a high initial capacity of 1410 mAh g−1 at 0.1C, excellent rate performance (715 mAh g−1 at 3.0C), and a low capacity decay rate of 0.086% up to 500 cycles at 3.0C. This work provides a new pathway to explore the catalytic mechanism of tungsten oxide in promoting redox kinetics of polysulfide conversion.