One step synthesis of NiCo-LDH/CoNi₂S₄/rGO composite on Ni foam for asymmetric supercapacitor

Abstract

The growth of NiCo-LDH/CoNi₂S₄/rGO composite on Ni foam was achieved with a simple one-step hydrothermal method. The obtained binder-free electrode (NiCo-LDH/CoNi₂S₄/rGO/Ni foam) was characterized with X-ray diffraction (XRD), field emission microscopy (FE-SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and galvanostastic charge/discharge (GCD). NiCo-LDH/CoNi₂S₄/rGO/Ni foam demonstrates a unique morphology with nanoparticles and nanowires mingled together, which endows the electrode large surface area as verified by the Brunauer–Emmett–Teller gas sorptometry measurement (BET). NiCo-LDH/CoNi₂S₄/rGO/Ni foam possesses excellent charge storage capabilities such as high areal capacitance, long cycling life and good rate performance. The asymmetric supercapacitor (ASC) with NiCo-LDH/CoNi₂S₄/rGO/Ni foam and activated carbon (AC) as positive and negative electrodes was assembled, characterized and successfully applied in practical applications, further confirming the great prospect of NiCo-LDH/CoNi₂S₄/rGO/Ni foam in energy storage.

Keywords:

• Supercapacitor
• layered double hydroxide
• graphene
• sulfide
• nanowire