Self-assembled flower-like structure of copper cobaltate nanosheets supported on nitrogen-doped carbon nanofibers as functional electrocatalyst for lithium/polysulfides batteries

The polysulfides shuttle effect and torpid kinetic are of the crucial barriers for lithium-sulfur batteries. Herein, self-assemble flower-like structure of copper cobaltate (CuCo2O4: CCO) nanosheets modified nitrogen-containing carbon nanofibers hybrid (denoted as CCONCFs) were designed as membrane electrode containing Li2S6 catholyte for lithium/polysulfides batteries, which promote electrochemical performance by inhibiting shuttle effect and enhancing the redox kinetics of lithium polysulfides. The conductive NCFs provide fast electronic transport and CCO nanosheets possess a strong affinity to sulfur species, which could effectively adsorb lithium polysulfides, boost their redox reaction catalytically-accelerate the reversible soluble/insoluble phases conversion, and greatly improve the utilization of active material. The results show that CCONCFs membrane electrode with 4.43 mg/cm2 sulfur loading exhibited stability cycling capacity, which delivered a high initial capacity of 1207 mA h/g at 0.2 C and sustain a capacity of 827 mA h/g after 350 cycles. Even at 8.85 mg/cm2 sulfur loading, the composite electrode shows a high specific capacity of 861 mA h/g and still maintains 733 mA h/g after 180 cycles. The assembled pouch cell with CCONCFs membrane was obtained with a specific energy density of 455 W h/kg.