Electrochemical Properties of RbAg[sub 4]I[sub 5] Solid Electrolyte

Abstract

The reversible behavior of silver electrodes in solid electrolyte has been tested by micropolarization studies. It has been found that while planar silver electrodes are reversible, the mixed silver‐electrolyte electrodes most commonly used in solid‐state batteries are not. The different behavior of the two electrodes has been related to the different physical aspects of their surfaces. In the case of the mixed electrolyte‐silver electrodes, there are preferential points of silver deposition and depletion corresponding to areas of low IR drop through the electrolyte. This explanation has been confirmed by the observed dendritic growth of silver along the preferential deposition points on the electrodes. Finally, it has been shown that even though planar silver electrodes behave reversibly at low current levels, they may also form dendritic growths at the current levels required for practical batteries. It appears that a practical rechargeable cell which uses electrolyte will require planar silver electrodes of very high surface area and the cell assembly will require a container which allows cell thickness change during cycling.