ELECTROCHEMISTRY OF THE NICKEL OXIDE ELECTRODE: PART IV. ELECTROCHEMICAL KINETIC STUDIES OF REVERSIBLE POTENTIALS AS A FUNCTION OF DEGREE OF OXIDATION

Abstract

Electrochemical kinetic studies have been carried out at the nickel oxide electrode showing that the reversible potential for the Ni^II–Ni^III system is independent of the state of oxidation of the bulk oxide in the electrode over a wide range of degrees of oxidation. The properties of the electrode are shown to be determined by the state of a surface phase, which is completely charged when the bulk oxide material in the electrode has been charged to 10% of its total charge capacity. Experiments on sparingly charged electrodes have proved that charging of the bulk oxide does not commence significantly until the electrode is charged to about 1.5%. Consecutive electrochemical reactions possibly involved in the charging process are discussed.