Co3O4/RGO/Co3O4 pseudocomposite grown in situ on a Co foil for high-performance supercapacitors

Abstract

A Co₃O₄/RGO/Co₃O₄ (CRC) pseudocomposite on a cobalt foil was prepared using a one-pot in situ hydrothermal method. Carrying out a chemical redox reaction between the Co foil and graphene oxide (GO), which involved an electrostatic attraction between GO (negative charge) and Co²⁺ (positive charge), allowed for the design and construction of a novel sandwich structure including Co₃O₄ (from Co²⁺ ions), RGO, and Co₃O₄ (from the Co foil). The CRC@Co nanocomposite was directly utilized as a binder-free supercapacitor electrode. When this composite was prepared at 200 °C for 24 h, it exhibited superior electrochemical performances: a specific capacitance of 2272.7 mF cm⁻² at 5 mA cm⁻², and a capacity retention of 81.6% after 2000 charge–discharge cycles.