A technology of preparing MnO2 nanowire from the low grade manganese ore

Abstract

Manganese dioxide has received considerable attention among transition metal oxides because of its outstanding structural flexibility. It is well known that MnO2 is of high theoretical specific capacitance (1370F g-1), natural abundance, environmental friendliness and low cost.1–3 MnO2 exhibits different electrochemical properties at very low loadings (about a few mg cm-2) on the current collector because of its extremely low electrical conductivity (10-5 to 10-6 Scm-1).4–7 Functional nanomaterials have been found wide applications in diverse areas due to their intrinsically different properties compared with bulk materials. Except for the excellent electrochemical property of MnO2 bulk materials, nanostructured manganese dioxide exhibits its efficient electrolyte/cation interfacial charge transports which enables improved pseudo capacitive performance, a good rate capability and reversibility. As a promising PC material among transition metal oxides, nano-MnO2 is of outstanding structural flexibility and exists in tunnel, spinel and layered crystallographic forms.8,9 To improve the performance, various MnO2 nanostructures with different morphologies, including nanoflowers,11,12 nanosheets,13–15 anotubes16 and nanowires17–19 have been synthesized. One-dimensional nanorods and nanowires are able to enhance electronic/ionic conductivity and shorten ion transport pathway for faradaic reactions.20–24