3D Hierarchical CNT‐Based Host with High Sulfur Loading for Lithium‐Sulfur Batteries

Abstract

AbstractA host material capable of efficiently transporting electrons, uniformly impregnating sulfur and effectively anchoring lithium polysulfide, is the key to realizing high‐loading lithium‐sulfur batteries. In this paper, we construct a three‐dimensional hierarchical host formed by one‐dimensional nitrogen‐doped carbon nanotubes(NCNTs) grown in situ on both sides of two‐dimensional oxides nanosheets. The uniformly grown NCNTs not only provide excellent overall conductivity, but also prevent stacking between two‐dimensional nanosheets, providing hierarchical pores for diffusion of molten sulfur, which is beneficial to the uniform impregnating of sulfur. Meanwhile, the two‐dimensional oxides nanosheets(NS) and cobalt nanoparticles have a strong chemical affinity with polysulfide, promoting the polysulfides adsorption and redox kinetics. Benefiting from the synergistic effects, Li−S batteries based on Co‐NCNTs/NS@S cathode delivers a high discharge capability of 1552 mAh g−1 at 0.1 C with a high sulfur content of 80 %, excellent rate capability of 860 mAh g−1 at 2 C and outstanding cycle life with a low capacity decay rate of 0.04 % per cycle over 550 cycles. Even at high sulfur loading of 4.8 mg cm−2, the cathode still exhibits an areal capacity of 4.6 mAh cm−2 after 100 cycles at 0.2 C.