Effect of B Doping on Capacitance Properties of NiO/Ni(OH)2 Electrode Materials

Two kinds of electrode materials, homogeneous NiO/Ni(OH)2 with micropits and β-doped NiO/Ni(OH)2(B) with microspheres were prepared on the surface of copper sheet by electroless plating and subsequent electrochemical anodic oxidation. The electrochemical performance of the two prepared electrode materials were characterized and tested by SEM/EDS, XRD and XPS. The results show that the two electrode materials are composed of Ni, NiO and Ni(OH)2, and the amount of doped B in NiO/Ni(OH)2(B) is up to 14.6wt%. The cyclic voltammetry measurements and galvanostatic charge-discharge tests show that both electrode materials have high electrochemical activity and reversibility. At the charge/discharge current density of 1 A/g, the specific capacitance of 1380 and 1930 F/g of NiO/Ni(OH)2 and NiO/Ni(OH)2(B) electrode materials after 10 000 charge/discharge cycles are obtained, showing high specific capacitance and good electrochemical stability. The electrochemical impedance spectroscopy shows that the electrochemical reaction resistance of NiO/Ni(OH)2(B) electrode material is about 2 orders of magnitude lower than that of NiO/Ni(OH)2. The Ragone curve reveals that the two kinds of electrode materials have higher power density and lower energy density. The doping of B in the NiO/Ni(OH)2(B) electrode materials increases the surface oxide content and forms micron microsphere morphology, which increases the surface area of the electrode and improves the contact and wettability between the electrode and the electrolyte, and reduces the band gap energy of the surface of electrode. These are the main reasons for its excellent pseudo-capacitance performance. © 2021, Science Press. All right reserved.