CoxMn3−xO4 hollow octahedrons: synthesis, growth mechanism, and their application in high-performance supercapacitors

Abstract

Co_xMn_3−xO₄ nanorods and hollow octahedrons have been fabricated through a simple hydrothermal method without using any template or surfactant. The growth mechanism is studied by characterizing the intermediate products during the phase transformation. In this strategy, the MnO₂ nanowire serves as the main precursor for the subsequent formation of Co_xMn_3−xO₄ nanomaterials. A merged dissolution–recrystallization and the Kirkendall effect mechanism has been proposed based on SEM, TEM and XRD characterization of the intermediate. Enhanced specific capacitance (266.84 F g⁻¹ at 5 mV s⁻¹), and good cycle stability (remaining 80.214% after 1000 cycles) are observed in aqueous electrolytes, which could be ascribed to the high charge accommodation, small ion-transport resistance, and good electric conductivity.