Preparation Of Nickel Cobalt Binary Metalic Compounds And Their Electrochemical Performance

Supercapacitors,as a novel energy storage device,are of great interest owing to their great advantages over traditional battery,such as fast charge / discharge capacity,excellent cycling stability,and environmental friendly.It is well-known that the electrochemical performance of supercapacitors mostly depend on the electrolyte and electrode materials,so it still the key point to develop excellent performance electrode materials.And applying the battery type materials to the electrodes of supercapacitors has become a hot topic in recent years.In our work,the micron ammonium nickel cobalt phosphate film are modified by the method of twice of hydrothermal treatment for the first time,a new type of ammonium nickel cobalt phosphate with two different structures of nano and micron of ammonium nickel cobalt phosphate were successfully prepared.The electrochemical tests were taken under the three electrode system,it is found that the specific capacitance can reach 190.3 mAhg^-1 with the current density of 1 Ag^-1.And when the current density increases from 1 Ag^-1 to 10 Ag^-1,the capacity remains 96.1 %.The capacitor assembly by the nano-micron structure of ammonium nickel cobalt phosphate as cathode material and porous carbon as anode material?R-NCoNiP//HPC?exhibits good electrochemical performance With the work voltage window of 1.55 V.The electrochemical performance results show the specific capacitance up to 133.3 Fg^-1 at the current density 0.2 Ag^-1,good rate performance(69.2 % capacity retention from 0.2 Ag^-1 to 10 Ag^-1).high power density of 7394 W kg-1,and the maximum energy density of 30 Wh kg-1.Moreover,even after 7000 cycles under the current density of 1 Ag^-1,the capacity still remains 77.5 %.In addtion,porous nickel cobalt phosphate was prepared by a hydrothermal-calcining process and applied as electrode material.The size of the porous structure can be adjusted by controlling the calcination temperature.It is found that the best electrochemical properties of nickel cobalt phosphate were obtained by the calcination temperature of 600?.The electrochemical tests were taken under the three electrode system in 6 M KOH solution.The specific capacitance can reach 185.2 mAhg^-1 at the current density of 1 Ag^-1,when the current density increases from 1 Ag^-1 to 10 Ag^-1,the capacity still remains 98 %.Moreover,the as-prepared material has good cycle stability(the capacity remains 68.5 % after 5000 cycles at the current density of 5 Ag^-1).