(Digital Presentation) Development of Bifunctional Oxygen Electrocatalysts for Electrically Rechargeable Zinc-Air Batteries

Abstract

Zinc-air battery is a promising battery system as it possesses high theoretical energy density and is cost-effective 3 . The theoretical energy density of a Zinc-air battery is 1086 Wh kg -1 , which is five times greater than that of lithium-ion batteries 2 . Moreover, zinc metal is one of the most abundant metals in the earth’s crust and is inexpensive. Rechargeable metal-air batteries operate based on two fundamental electrochemical reactions as Oxygen Reduction Reaction (ORR) during discharge and Oxygen Evolution Reaction (OER) during recharge processes, respectively 3 . Electrocatalytic activity of the bifunctional electrocatalyst towards these two oxygen reactions will decide the performance of the battery 1 . Recent advancements in catalyst development are the fabrication of rechargeable air electrodes using a single active material that is capable of bifunctionally catalyzing ORR and OER 3 . The development of bifunctional catalysts with high activity is necessary for rechargeable metal-air batteries, such as zinc-air batteries 3 . In this work, a perovskite-type LaFeO 3 material was synthesized using a citric acid-assisted sol-gel method and is investigated as bifunctional oxygen electrocatalyst for electrically rechargeable zinc-air batteries. Structural studies using X-ray diffraction revealed the formation of phase pure LaFeO 3 in space group Pbnm. This catalyst displayed considerable bifunctional catalytic activity for both oxygen reduction (0.74 V vs. RHE) and oxygen evolution reactions (0.40 V vs. RHE at 10 mA cm -2 ) in 1 M KOH electrolyte. Electrically rechargeable zinc-air batteries assembled using LaFeO 3 as the oxygen electrocatalyst deliver a specific capacity of 936.38 mAh g ( Zn) -1 after the 1 st discharge. Further details will be discussed in the poster. Financial support from Department of Science and Technology, Govt. of India under research grant number DST/TMD/MECSP/2K17/20 is gratefully acknowledged. References: [01] Y. Li, M. Gong, et. al., Nature communications , 4 , (2013), 1-7 [02] P. Gu, M. Zheng, et. al., Journal of Material Chemistry , (2017), 1-17 [03] D. U. Lee, P. Xu, et. al., Journal of Material Chemistry , 4 , (2016), 7107-7134