New Approaches for Synthesizing γIII-CoOOH by Soft Chemistry

Two soft chemical processes enabling the low-temperature synthesis of γIII-CoOOH are reported. Both processes consist of an oxidation reaction of αII-Co(OH)2 performed either in dry conditions (ozonation) or in solution. The γIII-CoOOH phase is usually prepared using a ceramic step process, which hinders its synthesis as a coating to improve the electrochemical performance of the active nickel hydroxide positive electrode in Ni-based batteries. Through this work, new γIII-CoOOH phases presenting properties quite different from those of the ceramic γIII-COOOH are obtained. The chemical stability in concentrated potassium hydroxide solution and the electrochemical behavior of these new phases have also been studied.