The Anodic Behavior of Planar and Porous Zinc Electrodes in Alkaline Electrolyte

The electrochemical performance of planar and porous zinc electrodes in an actual Zn/MnO(2) battery using lithium hydroxide (LiOH) electrolyte has been investigated. A large discharge capacity of 220 mAh/g is delivered by porous zinc electrodes while planar electrodes only deliver 130 mAh/g. The porous anode improves the rate capability of the rechargeable alkaline battery while enhancing the utilization of the active material. Using scanning electron microscopy and IR spectroscopy, the surface morphology and composition of the Zn anodes were studied at the end of the discharge process. While zincate ions and ZnO products were found after the discharge at the surface of the planar anode, no evidence for these products was found in the porous anode. The porosity of this surface prevents the detrimental buildup of zincate ions at the anodic surface that leads to passivation. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3387672] All rights reserved.