Hierarchical Tubular Structures Composed of Mn-Based Mixed Metal Oxide Nanoflakes with Enhanced Electrochemical Properties

In this work, a simple strategy is developed to synthesize hierarchical tubular structures (HTS) of Mn-based (Co-Mn, Ni-Mn, Cu-Mn, Zn-Mn) mixed metal oxides. The first step in the synthesis involves redox reaction mediated growth of nanoflakes on carbon nanofibers under hydrothermal conditions. After calcination in air, carbon nanofibers are removed and HTS of mixed metal oxides can be obtained with little structural deterioration. The resultant HTS are advantageous as electrodes for electrochemical energy storage. As an example, it is shown that the Co-Mn-HTS sample exhibits outstanding electrochemical performance as electrode materials for hybrid supercapacitors and lithium ion batteries.