Hollow cobalt sulfide polyhedra-enabled long-life, high areal-capacity lithium-sulfur batteries

Improving the electron and ion transport in sulfur electrodes and suppressing the lithium polysulfide shuttle have been the two major challenges with lithium-sulfur (Li-S) batteries. Here, we present a composite paper electrode consisting of hollow Co3S4 polyhedra, activated carbon nanofibers (ACNF), and pure sulfur powder for Li-S batteries. The hollow Co3S4 polyhedra with a porous shell structure provide large spaces to accommodate the polysulfides, possess ideal polar chemisorptive capability for immobilizing the polysulfide species, and have a higher conductivity than many polar metal oxides, facilitating fast reaction kinetics with the Li-S batteries. The composite electrode exhibits high sulfur utilization and maintains superior cycling stability in Li-S batteries with a high sulfur areal mass. A high capacity of 953 mAh g−1 at 1C rate could be achieved with a sulfur loading of 2.5 mg cm−2, and the capacity remains at 610 mAh g−1 after 450 cycles. Even with a high sulfur loading of 13.5 mg cm−2, the composite electrode delivers a high areal capacity of 13 mAh cm−2 at 0.3C rate.