Assessment of the Feasibility of Zn-Air Batteries with Alkaline Electrolytes Working at Sub-Zero Temperatures

Zn-air batteries with aqueous alkaline electrolytes exhibit poor low-temperature performance. Herein, the mechanisms of performance degradation at low temperatures are analyzed using a Co3O4/Ni foam electrode which can couple Zn-Co and Zn-air reactions in the battery, allowing better exclusion of the same factors. Except for the decrease in electrolyte conductivity, the decreased kinetics for both Zn and air electrodes are responsible for performance degradation. Besides, low temperature leads to a significant reduction in active surface area of the air electrode from 67.4 mF cm(-2) at 20 degrees C to 26.5 mF cm(-2) at -20 degrees C. However, the discharge voltage curves show that the Zn-Co reaction operates well at -20 degrees C, but the Zn-air reaction cannot work. Besides, the charging voltage for the Zn-air reaction even increases to 2.52 V at 10 mA cm(-2). Thus, the decreased activity of oxygen electrocatalysis reactions is the root cause of the failure. As a potential solution to address the issues of traditional KOH solutions, the performance of the CsOH solution is comprehensively investigated. Unfortunately, the results indicate that it cannot solve the low-temperature issues. Therefore, a new electrolyte system and effective catalysts that can maintain electrochemical performance at low temperatures need to be further explored.