Facile synthesis of α-MnO2 nanorods for high-performance alkaline batteries

Single-crystalline α-MnO2 nanorods have been successfully synthesized by a novel hydrothermal method based on the redox reactions between the permanganate anion MnO4– and H2O in mixture containing KMnO4 and HNO3. The products have been characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR) and Brunauer–Emmett–Teller (BET). The results prove that the grain size of α-MnO2 nanorods with the surface area ∼95.2 m2 g−1 is homogeneous with diameters ranging from 10 to 20 nm. The electrochemical property of the material shows that compared with the commercial electrolytic manganese dioxide (EMD), the discharge capacity of the as-prepared α-MnO2 nanorods is increased by 70.4%, 104.1% and 135.7% at different constant currents of 50, 250 and 500 mA g−1, respectively.