RAPID EVALUATION OF THE RECHARGEABILITY OF GAMMA-MNO2 IN ALKALINE MEDIA BY ABRASIVE STRIPPING VOLTAMMETRY

Cyclic abrasive stripping voltammetry is shown to provide the experime ntal basis for the evaluation of the rechargeability of gamma-MnO2 in 9 M KOH. Relative discharge capacities at different depths of discharg e (DOD) with respect to the first one-electron reduction of gamma-MnO2 are compared when metal ions such as Ba2+ or Zn2+ are additionally pr esent in the electrolyte solution. At about 30% DOD, resulting relativ e discharge capacities are essentially equal to those of AA cells eith er in the absence or presence of Ba2+ ions from about 10 discharge/cha rge cycles. However, the corresponding time scales are substantially d ifferent. While it takes about 2.7 h to complete 20 discharge/charge c ycles in the case of abrasive stripping voltammetric characterization, some 360 h are needed to cycle an AA-sized battery in the conventiona l manner.