Constructed conductive CoSe_(2)nanoarrays as efficient electrocatalyst for high-performance Li–S battery

摘要

Li-S battery has attracted great attention due to its high specific capacity and energy density.However,the serious polysulfides shuttle effect,low conductivity of sulfur and discharge product of lithium sulfide limit their application in commercial energy storage system.To solve the above problems,this work designs and constructs C@CoSe_(2) nano wire material as sulfur host for realizing high-performance Li-S battery.By combing the high conductivity,strong chemisorption,promising catalytic capacity and unique nanowire array structure,the C@CoSe_(2)/S electrode demonstrates a high specific capacity of 1264 mAh·g^(-1) with a low capacity decay of 0.051%per cycle at 0.2 C over 200 cycles.As expected,the battery delivers outstanding capacity retention over 1000 cycles at5 C and the decay is as low as≈0.026% per cycle.Moreover,even at higher sulfur loading of 5.1 mg·cm^(-2),the battery could still remain a stable areal capacity of 5.02 mAh·cm^(-2) at 0.2 C. More importantly,the experimental data and theoretical calculation results reveal that the internal mechanism of the improved electrochemical performance is the catalytic activation of CoSe_(2) on poly sulfides.