Tunable vacancy defect chemistry on free-standing carbon cathode for lithium-sulfur batteries

The defect chemistry is successfully modulated on free-standing and binder-free carbon cathodes for highly efficient Li–S redox reactions. Such rationally regulated defect engineering realizes the synchronization of ion/electron-conductive and defect-rich networks on the three-dimension carbon cathode, leading to its tunable activity for both relieving the shuttle phenomenon and accelerating the sulfur redox reaction kinetics. As expected, the defective carbon cathode harvests a high rate capacity of 1217.8 mAh g−1 at 0.2 C and a superior capacity retention of 61.7% at 2 C after 500 cycles. Even under the sulfur mass loading of 11.1 mg cm−2, the defective cathode still holds a remarkable areal capacity of 8.5 mAh cm−2.