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.