Enhanced capacitance of a NiO electrode prepared in the magnetic field

The enhancement of the surface alignment by magnetic field had a great theoretical and practical significance in the improvement of electrochemical capacitor. In the present study, the NiO nanowires were synthesized by liquid-phase reduction method, and the electrode was prepared within external magnetic field. The effects of magnetic field on the electrode surface and the electrochemical behavior were investigated. X-ray diffraction and scanning electron microscope studies showed that the applied magnetic field results in an orderly surface structure of the electrode, which induced an effective transfer path for the electrons and ions. Meanwhile, the orderly electrode surface improved the electrochemical capacitance, as well as decreased the internal resistance. It was found on the cyclic voltammetry and galvanostatic charge/discharge measurements that the electrode prepared with the magnetic field displays an increased capacitance (506 F g^?1), high power density (135.8 W kg^?1) and energy density (17.6 Wh kg^?1), and improved cycle stability compared to the electrode without magnetic field. Electrochemical impedance spectroscopy results demonstrated enhanced electrochemical properties for the addition of magnetic field.