Tailoring the Surface Morphology of a Nanostructured CuCo2S4 Electrode by Surfactant-Assisted Electrodeposition for Asymmetric Supercapacitors with High Energy and Power Density

Direct electrodeposition of ternary transition metalsulfides isextremely imperative, yet challenging. Here, we report a one-steppotentiostatic electrodeposition procedure of CuCo2S4-nanostructured electrode materials as high-performance faradaicsupercapacitor cathodes. The morphological evolution was carried outsystematically as an effect of the surfactant additive in the electrodepositionprocess, resulting in exclusive control of the morphology as nanoplates(without surfactant) and nanotubes (with surfactant). To circumventthe difficulties of the hard template synthetic route, here we adoptedelectrodeposition to design CuCo2S4 nanotubes,where surfactants act as soft templates. Besides, the hydrogen gasbubbles generated during the electrodeposition process adjusted thesurface electronic structure by creating a significant porous nature,which acts as a reservoir for ion/electron transportation and storageduring redox processes. The surface and structural factors of as-fabricatedCuCo(2)S(4) metal nanoplates (CCS-1) and nanotubes(CCS-2) were analyzed thoroughly, ensuring their high crystallinenature, attractive morphological phenomena, and increased surfacearea. The preliminary electrochemical tests of CCS-2 and CCS-1 electrodesin an aqueous medium (3 M KOH) as a faradaic electrode material providedspecific capacities of 1199 and 639 C g(-1) at 10A g(-1) current density, respectively. Despite thehigh applied current density value of 30 A g(-1),CCS-2 and CCS-1 showed retention values of 83.17 and 72.31% for 5000cycles, respectively. The superior-functioning CCS-2 electrode wasused as a cathode in constructed asymmetric supercapacitor (ASC) deviceassembly, which delivered 360.27 C g(-1) at 10 A g(-1) and a reserved capacity value with 95.23% retentionwhile cycling at 30 A g(-1) current density over 5000charge/discharge cycles. The very minimal interfacial resistance (Rs= 0.334 and Rct = 5.461) and relaxation time (0.409 s) values wereobserved for fabricated ASCs with a CCS-2 cathodic material, expressedat an increased energy density and power density value of 164.52 Whkg(-1) (at 10 A g(-1)) and 46.37 kWkg(-1) (at 30 A g(-1)), respectively.