MnO2 supported on acrylic cloth as functional separator for high-performance lithium–sulfur batteries

Abstract

Lithium-sulfur batteries (LSBs) are considered a most promising candidate for the next generation of energy storage systems due to numerous merits in high energy density. However, the shuttle effect of soluble lithium polysulfides (LiPSs), low sulfur loading and sluggish redox kinetics severely restrict available applications of LSBs. Herein, the MnO2 nano-flowers are synthesized on the surface of acrylic cloth carbon (ACC/MnO2) through hydrothermal process and used to decorated separator as a shuttle-inhibiting layer and catalyst for LSBs. Density functional theory (DFT) and Li+ diffusion coefficient (DLi+) calculations demonstrate that MnO2 exhibits strong chemical interacts with LiPSs and facilitate a rapid conversion of trapped LiPSs. Consequently, the batteries with ACC/MnO2 decorated separator exhibit a satisfactory rate performance and ultra-long cycle life of 500 cycles with a very low decay rate of 0.065% per cycle at 1.5C. Besides, the battery with a high sulfur loading of 5 mg cm−2, delivers a high reversible capacity of 712 mAh g−1 after 300 cycles at 0.2C. Even the sulfur loading increase to 8 mg cm−2 with low electrolyte/sulfur (E/S) ratio (6.25 μL mg−1), the battery delivers a high reversible capacity of 686 mAh g−1 after 100 cycles at 0.1C.