In situ growth of Co3O4 nanoparticles on α-MnO2 nanotubes: a new hybrid for high-performance supercapacitors

Abstract

A new MnO₂@Co₃O₄ hybrid with small-sized Co₃O₄ nanoparticles grown on α-MnO₂ nanotubes was prepared from a low concentration precursor solution by a facile two-step hydrothermal synthesis method, and its charge storage properties were investigated by cyclic voltammetry and galvanostatic charge–discharge measurements. Due to their hybrid structure, the well-dispersed Co₃O₄ nanoparticles not only facilitated the charge and ion transfer, but also hindered the dissolution of Mn species; this type of hybrid maximized the electroactivity of both components. The hybrid exhibited a specific capacitance of 234 F g⁻¹, which was greater than those of pristine α-MnO₂ nanotubes and a physical mixture of α-MnO₂ nanotubes and Co₃O₄ nanoparticles at a current density of 200 mA g⁻¹. The hybrid also showed good rate capacity and long-term cycling performance.