Effect of adding potassium hydroxide to an agar binder for use as the anode in Zn–air batteries

Agar–KOH was used for the Zn-powder binder at different concentrations in order to achieve the desired conductivity and physical properties. The presence of KOH causes the growth of a ZnO needle structure that covers the Zn-active materials. The formation of ZnO is proven by microscopy and structural measurements. To further understand the effect of KOH in the agar binder, Zn–air batteries are fabricated. The results show that the Zn–agar binder without KOH gives the highest discharge capacity of 505.0 mA h g−1. The results contradict earlier expectations that a ‘small’ amount of KOH in agar could increase the battery’s capacity.