Spinel manganese-cobalt oxide nanospheres anchored on nitrogen-containing carbon nanofibers as a highly efficient redox electrocatalyst in lithium/polysulfides batteries

The large-scale practical application of cost-efficient lithium/sulfur batteries with high energy density are impeded due to the shuttle effect and torpid kinetic of polysulfides. Herein, nitrogen-containing carbon nanofibers (NCFs) combined with spinel manganese-cobalt oxide (MCO) nanospheres (denoted as MCONCFs) were designed as membrane electrode containing Li2S6 catholyte for lithium/polysulfides batteries, which promote electrochemical performance by suppressing the shuttle effect and enhancing the redox kinetics of lithium polysulfides. The conductive NCFs provide fast electronic transport and anchored MCO nanospheres possess a strong affinity to sulfur species, which could effectively anchor lithium polysulfides, boost their redox reaction catalytically-accelerate the reversible soluble/insoluble phases conversion process, and greatly improve the utilization of active material. The results show that MCONCFs membrane electrode with 5 mg sulfur loading exhibited stability cycling capacity and improved reaction kinetics, which delivered a high initial capacity of 1177 mAh g−1 at 0.2 C and sustain a capacity of 745 mAh g−1 after 300 cycles. Even at 8.85 mg cm−2 sulfur loading, the composite electrode shows a high areal capacity of 7.8 mAh cm−2, and the areal capacity decay rate is 0.13% per cycle after 100 cycles. This effective method could significantly improve the application capacity of lithium/sulfur batteries.