Improve the Zinc Slurry-Air Battery Performance: New Operational Mode to Separate Effects

Abstract

In recent years, zinc air batteries received substantial interest as a viable next generation of batteries based on their merits of high energy densities, high performance, environmentally friendly, inexpensive, and abundant electrode material. Traditional secondary zinc air flow batteries use zinc metal as an anode. Severe dendrite growth and passivation limits the cycling behavior, which hinders commercialization in the industry. By substituting the zinc plate with a zinc slurry (zinc particles suspended in the alkaline media, typically with a high concentration of potassium hydroxide), the battery can in principle achieve higher energy density and attain more cycles but with very limited performance. Important questions related to such systems include the accessible percentage of Zn capacity, controlled by the formation of passivating layers on the particle and the intrinsic resistance of the slurry.Here, we present a new operational mode to investigate the performance of zinc slurry air battery. The anode of the test battery system consists of 5 cm2 nickel plate as current collector for 5 cm3 zinc slurry. The cathode consists of air electrode, bipolar plate, and current collector. Zinc particles (Spectrum) were suspended in 4M KOH stabilized by polyacrylic acid (PAA). In our testing, the polarization loss was measured and is separated from that associated with the air electrode using a reference electrode. The conductivity of the slurry was measured by the simply modified configuration of the cell. The utilization of zinc is measured by chronopotentiometry. The battery can work at 1.1 V with 200mA/cm2, and the slurry can achieve 48.7% utilization. Acknowledgements The authors gratefully acknowledge the support of the US Department of Energy Office of Electricity Storage Systems Program directed by Dr. Imre Gyuk and the University of Tennessee Governor’s Chair Fund for support of this work. Figure 1