3D Co-doped carbon nanosheets as high-performance electrodes for Li-S batteries

Figure. The Zn-based Co-MOF was grown in situ on the surface of a CFC substrate. Then, the PCoCNS product was obtained by pyrolyzation at 850 ℃ for 2 h under an Ar atmosphere. The electrochemical tests showed that the PCoCNS electrode has higher capacity and coulombic efficiency than that of the PUCNS eletrode. • A binder-free 3D petal-shaped metal-Co-doped carbon nanosheet (PCoCNS) electrode was constructed via a hydrothermal method. • The 3D petal-shaped framework of PCoCNS provided a convenient conductive pathway to accelerate electron/ion transfer and enhance sulfur utilization. • The PCoCNS@Li 2 S 6 cathode exhibited a high reversibility of 841 mAh g −1 with a high capacity retention of 91 %. • High CE values exceeding 97 % were obtained over 100 cycles at a current rate of 0.5C. • This electrode exhibited low polarization and delivered a capacity of 575 mAh g −1 even at the high rate of 3C. 3D petal-shaped Cobalt-doped carbon nanosheets (PCoCNS) were synthesized as excellent sulfur hosts for lithium-sulfur (Li-S) batteries. Co doping enhanced the affinity of the carbon surface for lithium polysulfides (LiPSs), inhibiting the shuttle effect. The electrocatalytic effect of the PCoCNS electrode exhibited enhanced polysulfide conversion kinetics, thereby promoting Li 2 S formation. Owing to the above advantages, the PCoCNS cathode exhibited satisfactory reversibility of 841 mAh/g with a high capacity retention of 91 %. Additionally, it displayed high coulombic efficiency (CE) values exceeding 97 % over 100 cycles at a current rate of 0.5C. Furthermore, the electrode demonstrated low polarization and exhibited an excellent rate performance, delivering a capacity of 575 mAh/g at the high rate of 3C. This study synthesized a promising sulfur cathode for enhancing the electrochemical performance of Li-S batteries.