Fabrication of an all-solid-state Zn-air battery using electroplated Zn on carbon paper and KOH-ZrO2 solid electrolyte

Abstract In the current efficient energy focused society, metal–air batteries (MAB), which have high theoretical energy densities in comparison with other batteries have attracted tremendous attention for electronics and electric vehicle applications. Efficient utilization of the active material in the negative electrode with oxygen from air as the positive electrode could enable the development of a lightweight and portable metal-air battery with large energy density. Zinc (Zn), which is an abundant and inexpensive material that exhibits small voltage fluctuation during discharge as well as large discharge capacity in a liquid electrolyte-based battery system, is a good candidate as the active material in a MAB. Therefore, in this work, a Zn-air battery is fabricated and characterized using electroplated metallic Zn on carbon paper in order to increase the working contact area between Zn and the carbon paper which serves as the current collector. A near theoretical discharge capacity of 814 mAh g−1 (Zn) was achieved in an aqueous KOH liquid electrolyte system. Meanwhile, an all-solid-state Zn-air battery using a sol-gel-derived KOH-ZrO2 solid electrolyte was also fabricated which demonstrated an initial discharge capacity of 30 mAh g−1 (Zn).