In Situ Microtomographic Monitoring of Discharging Processes in Alkaline Cells

Alkaline batteries have been in use for about 100 years. They show excellent performance characteristics, a favorable cost structure, and are extremely reliable [Solid State Ionics, 134, 139 (2000); J. Power Sources, 127, 45 (2004); J. Power Sources, 103, 120 (2001); J. Power Sources, 105, 127 (2002)]. The lifetime is strongly correlated with the dissolution process of the zinc particles in the anode material and the deoxidation of the manganese dioxide in the cathode material [Power Sources 7, Academic, New York (1979); J. Power Sources, 77, 127 (1999); J. Electrochem. Soc., 154, A481 (2007); J. Electrochem. Soc., 152, A1930 (2005); J. Power Sources, 186, 532 (2009); J. Power Sources, 156, 692 (2006)]. Parameters that affect the zinc utilization still have to be identified and optimized to continue the improvement of the cell performance [J. Power Sources, 96, 133 (2001)]. By in situ synchrotron tomography, the discharging process of an alkaline cell LR61 AAAA VARTA HighEnergy was visualized and analyzed quantitatively. The focus of attention was the observation of the zinc particles in the anode electrolyte material. The complete dissolution process of these zinc particles, i.e., the morphology and spatial distribution of zinc and zinc oxide, during discharging was discussed.