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

Abstract

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.

Cobalt‐Nickel Ultrathin Hexagonal Nanosheets for High‐performance Asymmetric Supercapacitors

“…[40] Generally, ZIF-67 should be obtained with the Co 2 + and the 2-methylimidazole (Hmim) (as shown in Figure S1). [41][42] In this study, with the low concentration of Hmim (Hmim/(Co 2 + ) = 3.5) in water, Co 2 + easily bind to OH À to form hydroxides. [43][44] The diffraction peaks of β-Ni(OH) 2 (JCPDS #14-0117) are almost same with those of β-Co(OH) 2 due to the similar ionic radii of Co and Ni.…”

α‐MnO2‐Sensitized SrCO3−Sr(OH)2 Supported on Two‐Dimensional Carbon Composites as Stable Electrode Material for Asymmetric Supercapacitor and Oxygen Evolution Catalysis

“…Electrochemical cell with three electrode configuration was constructed using 3 M KOH as the electrolyte. The average specific capacitance, energy density and power density of the electrode material were calculated by the galvanostatic charge discharge curve using the following equations: [48–50] …”

Ion‐exchange synthesis of microporous Co 3 S 4 for enhanced electrochemical energy storage

“…The autoclave was sealed, transferred to a muffle furnace, and heated at 120 C for 10 hours. 21,47 The electrode film was collected from the autoclave and after washing with DI water and EtOH several times, was dried in air. The loading weight of the active Co 3 O 4 and Co 3 S 4 electrodes is 2.31 and 2.67 mg, respectively.…”