Electrochemistry of Redox Couples on Lithiated Nickel Oxide Electrodes.

The kinetics of redox couples FeCN6-4FeCN6-3, FE2Fe3, Cr2Cr3 and quinhydrone have been investigated on mosaic NiOLi electrodes 0.5 - 0.5 cation Li, in aqueous sulfate solutions at various pH, using rotating flat electrodes and linear sweep voltammentry. To summarize the redox data, no oxidation or reduction processes occur at potentials very cathodic 200 mV to that of the reversible surface reaction Ni2 - Ni3. For oxidation reactions, all of the change in electrode potential is across the Helmholtz region, except at low overvoltages 100 mV and possible when specific adsorption occurs. For reductions, most of this potential change usually occurs across the space charge region of the semiconductor, depending on pH and the system considered. In the absence of redox couples, the differential capacitance exhibits a maximum at the potential of the reversible surface reaction Ni2 - Ni3. At more cathodic potentials,1C - E plots are linear with essentially the proper slope for the carrier concentration in the semiconductor, although some frequency dispersion is observed. Author