Fabrication and Characterization of Evaporated ZINC Anodes for Small-Scale ZINC-Air Batteries

Miniaturization of modern devices, including the advent of highly distributed Internet of Things nodes, has created a need for miniaturization in energy systems. Air batteries can be an attractive power source for such small-scale devices. This paper investigates fabrication of thin zinc anodes for zinc-air batteries using a thermal evaporation technique. Zinc anodes produced by thermal evaporation are found to be of high purity, approximately 96% dense, and smooth (roughness less than 0.1 micron). Anodes up to 8 microns in thickness are demonstrated. The structural characterization of the evaporated zinc films was performed by profilometry and scanning electron microscopy. The purity of the evaporated film was determined by the energy dispersive X-ray spectroscopy. Thin zinc anodes fabricated by evaporation exhibited utilization of 96.5% at 10 mA (5C rate) discharge. Specific capacity was 791mAh/g, approaching the theoretical limit of zinc-air batteries (820mAh/g). The anodes produced by evaporation offer the potential to fabricate high energy density thin film microbatteries.