Investigating the kinetic mechanism of the oxygen reduction reaction in non-aqueous solvente

Abstract

Due to their high theoretical energy density, lithium-air batteries represent a promising substitute for the state-of-art lithium ion batteries when it comes to energy storage and conversion. However, practical systems have not yet achieved the expected high energy density due to solvent instability, low reactions rates, and chemical irreversibility during the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Because the role that the addition of a catalyst plays in the ORR mechanism is not fully understood, this project proposes investigating the ORR mechanism using an electrocatalyst that consist of platinum and carbon nanoparticles, focusing on how the electrocatalyst grain size influences this mechanism. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Raman, and electrochemical experiments shall help to elucidate which species participate in ORR catalysis. Such analyzes will complement to the electrochemical impedance spectroscopy data and aid proposal of a kinetic model for these systems. These strategies will assist catalyst development by providing information about how electrode type and catalyst grain size affect the reaction mechanism. (AU)