It has been shown that Raman spectroscopy is a powerful technique for studying the charge and discharge processes, and the open‐circuit behavior of nickel hydroxide used in the foam technology of alkaline rechargeable batteries. It is observed, in particular, that nickel hydroxide initially activated by potential cycling returns to its initial state when the electrode is left at the open‐circuit potential for a long period. Remanent cations formed by the activation procedure, which give a high conductance to the nickel hydroxide and are not reduced during the discharge process, will be completely reduced if the electrode is held at open‐circuit potential for a long period. Therefore, the electrode will need to be reactivated before subsequent use.