Electrochemical Studies of Single Crystals of Lithiated Nickel Oxide

Lithiated nickel oxide is a p‐type semiconductor. Electrodes were made from single crystals of this material and their d‐c and a‐c behavior was studied in acid electrolytes. These electrodes are nearly ideally polarizable over an appreciable potential range. At 0.5–1.0v, with respect to a hydrogen electrode in the same solution, there is observed a capacitive impedance, which is associated with the charging of a space charge region due to the exhaustion of holes near the surface. The experimentally determined flat‐band potential for is p H‐dependent, which indicates the existence of an adsorbed surface layer in equilibrium with protons in the electrolyte. Near zero potential hydrogen evolution is observed, and above 1v faradaic processes occur.