Cobalt Nanoparticles Decorated?Wire in Tube?Framework as aMultifunctional Sulfur Reservoir

The various designs of sulfur host materials for thelithium-sulfur (Li-S) battery have attracted ever-increasinginterest in alleviating the fatal shuttle effect of lithium polysulfide(LiPS) intermediates. Designing host materials for sulfur cathodesneeds particular attention in both physical confinement and surfacechemistry. Herein, the Co, N codoped"wire in tube"carbonfiber(WIT-Co) is rationally fabricated and serves as the sulfur host.Benefiting from the synergistic effects of excellent LiPS absorptionand electrocatalysis capability, the WIT-Co/S cathode reveals ahigh initial capacity of 1462 mAh g-1at 0.1 C and stable cyclingperformance of 650 mAh g-1at 2.0 C after 400 cycles with a low-capacity decay of 0.021% per cycle. Notably, even with the highsulfur loading of 5.6 mg cm-2and low electrolyte/sulfur ratio of 5 mu Lmg-1, the WIT-Co/S electrode still exhibits an excellent arealcapacity of 4.8 mAh cm-2at 0.2 C after 100 cycles. This work provides a superior structure of the sulfur host, which not onlyaccelerates the conversion of LiPSs but also alleviates the shuttle effect, therefore facilitating the practical application of Li-Sbatteries.