Design of Oxygen-doped Co3S4 Hollow Nanosheets by Suppressed Sulfurization for Supercapacitors

Cobalt sulfides can be considered as auspicious electrode materials for supercapacitors due to the good electrical conductivity and high reversible redox capability. In this study, the O-doped Co3S4 hollow nanosheets supported on carbon paper (O-Co3S4/CP) are facilely prepared through a suppressed sulfurization method by using CP-supported Co-ZIF as the precursor and methanol as the solvent. The hollow nanosheets not only offer fast transport pathways but also provide abundant redox active sites. Furthermore, theoretical calculations indicate that the O doping can enhance the adsorption ability of OH- on O-Co3S4 with electrochemical activity and electrical conductivity improvement. Owing to the advantages of the appropriate composition and unique structure, the as-made hollow structure O-Co3S4/CP shows a remarkable specific capacitance of 755 F g(-1) at a current density of 1 A g(-1), while a good rate performance of 65 % capacitance retention at 10 A g(-1) can be reached. Moreover, the asymmetric supercapacitors assembled by O-Co3S4/CP and activated carbon electrodes yield an energy density of 21.3 Wh kg(-1) with power density of 0.75 kW kg(-1). The present work can offer a useful guidance for the exploitation of O doped cobalt sulfides hollow nanosheets for supercapacitors.