Phosphorous/oxygen co-doped mesoporous carbon bowls as sulfur host for high performance lithium-sulfur batteries

Abstract

Lithium−sulfur batteries are particularly attractive due to their high theoretical energy density. Unfortunately, the commercial application of lithium−sulfur batteries is now impeded by the “shuttle effect” of soluble polysulfides. Herein, we demonstrate that the polysulfides can be effectively confined to the phosphorous/oxygen co-doped mesoporous carbon bowls (P/O-MCB) via the strong electrostatic dipole–dipole interaction. Different from other doping methods, the P2O5 can not only be used as the phosphorous and oxygen sources for co-doping, but also generate enormous pressure difference on the surface of hollow mesoporous carbon sphere under the action of surface tension, leading to the formation of porous bowl-like morphology. Benefiting from the P/O co-doping, high surface area, and unique bowl-like morphology, the S@P/O-MCB electrode delivers an initial capacity of 897 mAh g−1 at 1C and retains a reversible capacity of 489 mAh g−1 after 800 cycles. More importantly, the S@P/O-MCB electrode shows an outstanding areal capacity of 5.5 mAh cm−2 at a high sulfur loading of 5.02 mg cm−2.