Fabrication of flower-like Ni3(NO3)2(OH)4 and their electrochemical properties evaluation

Graphical abstract: Ni3(NO3)2(OH)4 nano-flakes materials, which have a flower-like structure, were successfully synthesized by a facile solvothermal method without adding any surfactant. The as-prepared Ni3(NO3)2(OH)4 possesses a maximum specific capacitance of 2212.5 F g−1 at the current density of 5 mA, suggesting its potential application in electrode material for secondary batteries and electrochemical capacitors. Highlights: ► Flower-like Ni3(NO3)2(OH)4 materials were fabricated in a simple method. ► High specific capacitance of 2212.5 F g−1 has been achieved. ► For the first time the effects of concentration and temperature on its specific capacitance has been studied. -- Abstract: Flower-like Ni3(NO3)2(OH)4 was successfully synthesized by a facile solvothermal method. The microstructure and surface morphology of prepared Ni3(NO3)2(OH)4 were physically characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and transmission electron microscope (TEM). The electrochemical properties studies were carried out using cyclic voltammetry (CV), chronopotentiometry technology and AC impedance spectroscopy, respectively. The results indicate that the flower-like structure has a profound impact on electrode performance at high discharge capacitance. A maximum specific capacitance of 2212.5 F g−1 at the current density of 5 mA could be achieved, suggesting its potential application in electrode material for secondary batteries and electrochemical capacitors. Furthermore, the effects of Ni(NO3)2·6H2O concentration and temperature on the microstructure and specific capacitance of prepared Ni3(NO3)2(OH)4 have also been systematically studied. The results show that flower-like structure can be formed when the concentration is appropriate, while the temperature has just little effect on its electrochemical properties.