Rapid oxidation-etching synthesis of low-crystalline δ-MnO₂ tubular nanostructures under ambient with high...

The 1D low-crystalline and ultrathin MnO₂-RT nanotubes consisted of tiny nanoflakes are rapid synthesized at ambient temperature through a facile oxidation-etching method, where Cu nanowires are served as sacrificial templates. Meanwhile, the MnO₂-RT nanotubes can be undergone further nucleation and growth to generate 3D porous MnO₂ nanotubes by calcination treatment and hydrothermal reaction, respectively. Importantly, the high specific capacitance of 384.6 F g^-1 is obtained at the current density of 0.25 A g^-1 for the low-crystalline MnO₂-RT nanotubes, owing to its ultra-thin wall thickness, high surface area and highly disordered structure. Furthermore, the cycle stability of the low-crystalline MnO₂ nanotubes can be improved by hydrothermal treatment, owing to the enhanced crystallinity.