Self-assembled Mn₃O₄ nano-clusters over carbon nanotube threads with enhanced supercapacitor performance

A well defined carbon nanotube threaded trimanganese tetroxide (Mn₃O₄@CNT) nanocomposite has been fabricated through a facile hydrothermal route using acetylacetone as a chelating agent. The Mn₃O₄ nano-clusters are formed by the self-assembly of numerous Mn₃O₄ nanostructures and the CNTs are uniformly decorated on the body of Mn₃O₄ nano-clusters to improve the conductivity of the composite. The porous and well-designed architecture of the Mn₃O₄@CNT composite could be expected to offer more electroactive sites for pseudocapacitive reactions and shorten the transportation path for the electrolyte ions. Due to these properties as well as the synergistic effect of CNTs and Mn₃O₄ nano-clusters, the as-synthesized Mn₃O₄@CNT composite, which was primarily used as a pseudocapacitive material, showed a higher specific capacitance of 81.9 F g⁻¹ at a current density of 0.6 A g⁻¹ with good cycling stability. The delivered capacitance of the composite is comparatively higher than that of the pristine Mn₃O₄ (53.5 F g⁻¹). The facile preparation approach to balance the higher electrochemical properties of the transition metal oxides with highly conductive carbon nanotubes provides the potential for the development of novel nanocomposites for energy storage devices.