3D zinc sponge anode in zinc air battery

Abstract

Zinc-based batteries offer an inexpensive, safe, and environment friendly alternative to the fire-prone lithium-ion battery. Zinc-based batteries, especially Zinc-Air Battery (ZABs), have a high specific power of up to 400Wh kg-1. However, the rechargeability of ZABs still remains low because of several factors such as dendrite formation, passivation, and corrosion. In order to suppress dendrite formation, the zinc oxide-metal conversion needs to be controlled so that the zinc oxide could be converted back to metal in a homogenized way. In this project, we mitigate the inefficient zinc utilization by replacing Zn-Foil anode with a three-dimensional (3D) sponge architecture without the need of electroreducing by using green material porogen. The porous structure serves as a nucleation site to capture Zn ions and homogenize the ion conversion. Cheap and off-the-shelf products are used to replace the highly-cost water-insoluble CMC resin as a porogen; Sodium Dodecyl Sulfate(SDS), Corn Starch (CS), and Tapioca Starch (TS). The heating method for the anode was also modified to increase the active material while maintaining good mechanical properties. Throughout the modification, we obtained an increase of ZAB capacity by 278% and cycle rate by 538%. Dendrites formation also managed to be suppressed through the implementation of 3D sponge anode.