A new synthetic route to hollow Co3O4 octahedra for supercapacitor applications

Abstract

Co₃O₄ hollow octahedra were successfully synthesized via a facile one-step solvothermal route. Time-resolved electron microscopy and X-ray diffraction analyses revealed that the Co₃O₄ hollow octahedra were formed through the self-assembly of primary nanocrystals followed by subsequent Ostwald ripening. Subtle control over the reaction conditions led to different morphologies (hexagonal plates and nanocubes) and crystal structures (β-Co(OH)₂–Co₃O₄ composite). The unique hollow nanostructure rendered our Co₃O₄ potentially useful for charge-storage applications. To prove its usefulness, the pseudocapacitive performance of the Co₃O₄ hollow octahedra as a supercapacitor electrode was evaluated and exhibited a charge storage capacity of 192 F g⁻¹ with good long-term cyclability.