Fe doped δ-MnO2 nanoneedles as advanced supercapacitor electrodes

Abstract

Fe-doped δ-MnO2 nanoneedles have been successfully synthesized via a hydrothermal method as electrode materials. The morphologies of as-synthesized samples were characterized by SEM and the role of Fe3+ as a structure directing agent on the formation of MnO2 nanoneedles was investigated. The electrode exhibits maximum specific capacitance of 627.3 F g−1 at a current density of 1 A g−1, far exceeding the capacity of MnO2 monomers. Furthermore, the capacitance retention was measured to be 94.2% after 3000 cycles, showing remarkable cycling stability. The activation of Fe3+ in δ-MnO2 nanoneedles attributes to the enhancement of electrode conductivity and electrochemical performance. In principle, the results indicate the potential application of our samples in supercapacitor electrodes.