Study of the Electrolyte Penetration Depth of Cathodes in Zn-Air Batteries by Electrochemical Impedance Spectroscopy (EIS)

Abstract

Metal-oxygen cells exhibit highest theoretical energy densities. State-of-the-art metal-oxygen cells mainly suffer from severe cyclic aging and low Coulombic efficiency. One of the major challenges is the development of suitable electrolytes and electrocatalysts for the oxygen reduction and gas evolution reactions. One of the major limiting factors on performance and round-trip efficiency is the catalyst used. Today´s metal-air batteries still suffer from high charge- and discharge overpotentials caused by insufficient catalytic activity of the used electrode active mass. The major goal is to reduce overpotentials by using bifunctional catalysts catalyzing both the oxygen reduction reaction (ORR) as well as the oxygen evolution reaction (OER) and to improve the porous electrode structure increasing the electrochemical active surface using different electrode production techniques like hydraulic hot pressing, vacuum plasma spraying or reactive rolling and mixing (RMR) technique.