Abstract
The involvement of the polysulfide electrocatalysts has become an effective strategy to improve the durability of lithium-sulfur batteries (LSBs) by alleviating the precipitation and dissolution of lithium sulfide in the electrolyte. In this study, a FeCoP quantum dot (FeCoP-QD)-decorated nitrogen-doped carbon nanosheet (CoFeP-NCS) composite was prepared as a sulfur host for LSBs. In comparison with the other sulfur hosts reported in literature, the optimal FeCoP-NCS sulfur host exhibited a fantastic bidirectional catalytic effect by greatly accelerating sulfur reduction during discharge and Li2S oxidation during charging. The NCS substrate matrix with large specific surface area and high porosity provided the necessary channels for electron and ion transport. The assembled LSBs with S@FeCoP-NCS cathode displayed a high capacity of 406 mA h g-1 at 5 C current density. Meanwhile, an excellent cycling performance with a capacity decay rate of 0.07% per cycle was observed for 500 cycles at 1 C. This work demonstrated the potential of FeCoP-NCS composite to be employed as LSBs electrode material with high-rate performance and long-cycle stability.