Electrospun three-dimensional cobalt decorated nitrogen doped carbon nanofibers network as freestanding electrode for lithium/sulfur batteries

Cobalt decorated nitrogen doped carbon nanofibers (Co, N-CNFs) were successfully fabricated by electrospinning technique based the cobalt based zeolitic-imidazolate frameworks-67 (ZIF-67)/PAN solution as precursor. The as-synthesize fibrous Co, N-CNEs membrane was employed as positive current collector containing Li2S6 catholyte solution for lithium sulfur batteries. Co, N-CNEs inhibited the dissolution of polysulfides shuttle effect and demonstrated as positive catalyst accelerating kinetic redox reaction of lithium polysulfides/sulfide. In addition, metallic cobalt achieves the purpose of reducing polarization and increasing specific capacity by promoting nucleation of lithium sulfide on the surface of Co, N-CNEs. Li2S6 catholyte impregnated Co, N-CNEs electrode (sulfur loading: 4.74 mg) exhibits the first discharge capacity of 1166 mA h g(-1) and matins at 938 mA h g(-1) after 300 cycles at 0.2 C, which is superior cycling performance than N-CNEs. Even at 7.11 mg sulfur loading, the composite electrode shows a high area capacity of 6.47 mA h cm(-2). Furthermore, a steady-state of lithium anode resulting through effective suppression of polysulfide shuttle effect is also demonstrated to contribute significantly to enhance electrochemical performance. (C) 2020 Published by Elsevier Ltd.