Facile synthesis and magnetic properties of manganese dioxide nanowires

Abstract

A large number of MnO 2 nanowires were fabricated by a facile hydrothermal method. The nanowires have a tetragonal pyrolusite structure and a smooth surface. The common bulk defects such as dislocations, twinnings and stacking faults are not detected by HRTEM measurement. The magnetisation dependence of temperature indicates that the magnetisation, linearly and monotonically, increases with decreasing temperature in the range 300-80 K, revealing the paramagnetic properties of the nanowires. The first discharge capacity reaches 223.5 mA h g À1 , and the value of capacity steadily decreases during the following cycles, down to an acceptable 122.3 mA h g À1 after 25 cycles. The high surface ratio of nanowires is the main reason for the excellent discharge cycle property of the MnO 2 nanowires.

Formation Mechanisms of Nanocrystalline MnO2 Polymorphs under Hydrothermal Conditions

“…This reaction has been shown to produce α-, β-, and δ-MnO 2 under hydrothermal and refluxing conditions. ,,− Previous studies on MnO 2 synthesis report needle shaped nanocrystals of α- and β-MnO 2 and sheet-shaped δ-MnO 2 nanocrystals. However, the studies differ in their claims about how to control the crystalline phase, e.g., via pH, reaction time, and temperature.…”