Mathematical modeling and numerical analysis of the discharge process of an alkaline zinc-cobalt battery

Zinc-cobalt batteries with cobalt oxide (Co3O4) as the positive electrode material are promising energy storage devices, due to their safety, remarkable energy densities, and good cycle stability. To understand the discharge characteristics of an alkaline zinc-cobalt battery for design optimization, a mathematical model of the discharge process is established based on the single-domain method, which couples the species transport in the porous electrodes with the electrochemical reactions. After model validation, the effects of different design parameters on the discharge performance of zinc-cobalt batteries are investigated, and the design strategies for the battery are proposed. It is found that a thin cathode with a large porosity can lead to a high specific capacity, and a low loading with a large electroactive area is beneficial for a high discharge voltage. The separator thickness has little effect on the discharge performance of the battery. Using the electrolyte with a high concentration is favorable for the improvement of the output voltage. The results obtained from this work can provide useful guidance for improving the discharge performance of aqueous zinc-cobalt batteries.