Preparation And Pseudocapacitive Properties Of Nickel Oxide/hydroxide Electrode Materials With Different Boron Contents

As a new type of energy storage device,supercapacitors have been widely used in recent years.The electrode material is an important factor affecting the performance of supercapacitors,and the composite electrode material of nickel-based(hydro)oxide combined with boron has excellent performance.In order to obtain the optimal B doping amount,select a better substrate material,and further improve the performance,in this paper,Ni-B doped with different B contents were electrolessly plated on copper sheets and foamed copper substrates respectively,and then electrochemical oxided in alkaline solution.Four kinds of thin film electrodes of Ni O/Ni(OH)2,Ni O/Ni(OH)2(0.5B),Ni O/Ni(OH)2(1B)and Ni O/Ni(OH)2(2B)were obtained.Theprepared thin film electrodes were characterized and electrochemically tested.The main research results are as follows:(1)Four kinds of thin film electrodes were successfully prepared on the copper sheet by electroless plating and then electrochemical oxidation.It can be seen from SEM/EDX,XRD and XPS analysis that all of the four electrodes are composed of Ni O and Ni(OH)2,and B is doped with its oxide.With the increase of B doping amount,the particles witha microsphere structure on the surface of the base material are formed.As the number of the microsphere increases,the specific surface area of the electrode is increased,and the capacitance is improved.After the redox peak analysis of cyclic voltammetry measurements,both materials have good electrochemical activity and reversibility.According to Galvani charge and discharge test and the analysis of the AC impedance test,it is found that with the increase of the current density,the discharge time and capacitance of the electrode are reduced,and the higher the content of doped B is in the thin-film electrode,the higher its specific capacitancepossesses,and the corresponding its energy density is also higher.When the charge-discharge density is 1A/g,after10,000 charge-discharge cycles,it is found that Ni O/Ni(OH)2,Ni O/Ni(OH)2(0.5B),Ni O/Ni(OH)2(1B)and Ni O/Ni(OH)2(2B)thin film electrodes have specific capacitances of 5.7F/g,6.4 F/g,6.5 F/g and 13.7 F/g,respectively,and the capacitance retention rates are 105%,109 %,109% and 189%,which indicate that the more B doping,the better the cycle performance.It can be seen from the above that the electrochemical performance increases with the increase of B doping amount,and the electrochemical performance of Ni O/Ni(OH)2(2B)is the best among those electrodes.(2)Similarly four kinds of thin film electrodes were successfully prepared on foam copper by electroless plating and then electrochemical oxidation,which were characterized by SEM/EDX,XPS,XRD,cyclic voltammetry curve,Galvani charge and discharge test and AC impedance test.FCu/Ni O/Ni(OH)2(2B)has the best performance.When the charge-discharge density is 1 A/g,after 3000 charge-discharge cycles,FCu/Ni O/Ni(OH)2,FCu/Ni O/Ni(OH)2(0.5B),FCu/Ni O/Ni(OH)2(1B)and FCu/Ni O/Ni(OH)2(2B)thin film electrodes have specific capacitances of 128 F/g,90 F/g,200 F/g and 230 F/g,respectively.Therefore Ni O/Ni(OH)2(2B)has the best performance.Comparing the flexible copper sheet with the foamed copper substrate,it is found that the electrode material prepared with the foamed copper substrate has greater capacitance,higher energy density,power density and better performance.