An ant-nest like hierarchical nanoreactor for highly efficient sulfur species redox reactions

Abstract

The main challenge in the practical exploitation of lithium-sulfur (Li-S) batteries is to resolve the problems of the sluggish liquid-solid conversions and the diffusion loss of liquid polysulfides especially at high sulfur loading. Herein, a novel bio-inspired reactor with ant-nest like architecture was tailored for Li-S electrochemistry, which combines abundant active nickel nanoparticles with hierarchical porous carbon-nanosheets network (HPCN/Ni). The nanoreactor provides multiple functions including strong trapping efficiency with polysulfides, fast transfer of ions/electrons and liquid sulfur species, and sufficient catalytic activity. The cooperative effects could accelerate Li-S redox reactions and improve sulfur utilization. Enhanced by the highly efficient HPCN/Ni naonoreactor, Li-S cells demonstrate a high specific capacity of 1437.9 mAh g−1 at 0.1 C, remarkable rate performances such as 900 mAh g−1 at 2 C, and exellent cycling stability with a high capacity retention of 734.2 mAh g−1 after 300 cycles at 1 C. Even at a high sulfur area loading of 5.63 mg cm−2, a high area capacity of 4.75 mAh cm−2 could be achieved. This contribution affords a fesible approach to design and construct nanoreactors with high efficiency for Li-S batteries and the analogous applications.