Investigations on Zinc Electrode with Reference to Leclanche Dry Cells

Central Electrocheinical Research Institute, Karaikudi-623 006

Manuscript received 13 July 1988, revised 15 October 1990, accepted 15 April 1992

The paper reports the experimental results on the anodic polarisation behaviour of commercial zinc in different concentrations of ammonium chloride ranging from 0 5- 6.0 N, over a wide range of current density of 5-1000 mA cm^-2 The purity of the commercial zinc is determined as 99 972% it is found that any concentration between 2 and 5.5 N of ammonium chloride can be suitable for use in zinc cells but the most optimun concentration is 5.5 N, at which the anode potential and the internal resistance of the electrode system are minimum. The corrosion rate of commercial zinc in 5.5 N ammonium chloride is determined for the constant time by conventional weight loss method. Typical scanning electron microscopic photographs of the polarised electrode surface are compared with the one obtained with unpolarised surface.