Three-dimensional carbon architectures with O doping and rich defects for catalytic conversion of polysulfides

To deal with the notorious shuttle behavior and sluggish conversion of lithium polysulfides (LiPSs), heteroatoms doping and defects creating are practical strategies for improving capture and catalytic conversion of LiPSs. In this work, O doped porous carbon materials (OPC) with a 3D hierarchical structure, consisting of 2-4 mu m carbon sheets decorated with macrospores of 0.2-0.4 mu m, was fabricated with MgO template. It is found that the increasing the carbonization temperature and the amount of MgO will make OPC rich in oxygen functional groups and defect sites. Electrochemical measures show that the OPC12-800 achieves reversible capacity (an initial discharge specific capacity of 1448.4 mAh g(-1) at current density of 0.1 C) and cycling performance (717.7 mAh g(-1) at 2 C over 200 cycles). The excellent electrochemical performance is attributed to the hierarchical porous structure, abundant C-O/C=O and defects, which effectively adsorbs polysulfides and promote faster redox reaction of LiPSs. This study provides an alternative to improve the performance of carbon materials as host of Li-S batteries by regulating the types of oxygen-containing functional groups and defects on carbon surface.