Abstract:
Mathematical models of alkaline rechargeable nickel cell systems (e.g., Ni-Cd, Ni-H<sub>2</sub> and Ni-MH) have so far been developed based on the assumption that the active material at Ni electrode exists primarily in a single phase as Beta-NiOOH -- Beta-Ni(OH)<sub>2</sub>, despite enough experimental evidence for the second phase, i.e., Gamma-NiOOH -- Alpha-Ni(OH)<sub>2</sub>, especially under conditions of extended coverage. Here, we have incorporated the additional couple of Gamma-NiOOH -- Alpha-Ni(OH)<sub>2</sub> into the modeling of the Ni electrode.