One stone two bird: Reduced oxide graphene supported g-C3N4 quantum dots implements efficient capturing/catalytic polysulfides conversion and high sulfur loading for lithium-sulfur battery

作者：Zhao, Dengke; Xu, Zirui; Yu, Xiaolong; Chen, Minzhe; Wu, Oikai; Zhou, Kai; Zhou, Wei^*; Ma, Liang^*; Wang, Nan^*

来源：Chemical Engineering Journal, 2023, 474: 145983.

DOI：10.1016/j.cej.2023.145983

• Efficient adsorption and catalytic activity for
• polysulfide
• Lithium-sulfur batteries
• High sulfur loading

Simultaneously increasing the sulfur (S) loading and enhancing the adsorption/catalytic capacity towards lithium polysulfides (LiPSs) is necessary to design efficient carbon-based sulfur cathode for lithium-sulfur batteries (LSBs). Herein, two-dimensional reduced graphene nanosheets supported g-C3N4 quantum dots (rGO/gC3N4 QDs) composites are prepared as novel cathode materials for LSBs. Theoretical calculation and characterization show C3N4 QDs incorporation has the effect of one stone two bird, where C3N4 QDs with nanosizing can not only expose as many LiPSs adsorption sites to inhibit the "shuttle effect" and boost the kinetics, but also as possible reduce its effect on rGO to keep high conductive and abundant mesoporous structure to achieve high S utilization and accelerate Li+/charge transfer. Therefore, the S@rGO/C3N4 QDs cathode displays the high initial discharge capacity (1013.9 mAh/g) at 1C and retention capacity (935.2 mAh/g) after 500 cycles (capacity decay of 0.016% each cycle). Even under high S loadings (16.2 mg cm-2) and poor electrolyte condition (E/S ratio is 6.0 mu L mg-1), it also delivers the superior initial areal capacity (16.1 mA cm-2). This study enriches the design strategies to cheap and excellent carbon-based S cathode.

• 单位
  广州大学; 茂名学院