The Synergistic Influences of OH[sup −] Concentration and Electrolyte Conductivity on the Redox Behavior of Ni(OH)[sub 2]/NiOOH

The synergistic influences of the concentration and electrolyte conductivity on the redox behavior of for nickel oxide-coated graphite electrodes are clearly demonstrated by voltammetric and impedance analyses. The increase in the concentration and electrolyte conductivity effectively promote the utilization of active nickel species and the electrochemical reversibility of , indicating the simultaneous involvement of and cations in the redox transition. The upper limit for utilizing Ni oxyhydroxides is mainly determined by the concentration, which is facilely reached by increasing the electrolyte conductivity (adding ). The synergistic phenomena could be very important in the applications of Ni oxide-based batteries, supercapacitors, sensors, electrochromic devices, and organic synthesis.