Evidence of catalyzed oxidation of Li2O2 for rechargeable Li–air battery applications

Abstract

The oxidation kinetics of Li₂O₂ was studied in a carbonate-free electrolyte using electrodes consisting of non-catalyzed and catalyzed Vulcan carbon (VC) and chemically synthesized Li₂O₂ particles. VC and Au nanoparticles supported on VC (Au/C) were fairly inactive for catalyzing the oxidation of Li₂O₂, where oxidation currents greater than 10 mA g_carbon⁻¹ were found only at voltages equal to and greater than 4.0 V vs. Li (V_Li). Pt and Ru nanoparticles supported on VC (Pt/C and Ru/C) could significantly increase the kinetics of Li₂O₂ oxidation, where Li₂O₂ could be removed largely at voltages below 4 V_Li. In addition, Pt/C and Ru/C showed quick initiation of Li₂O₂ oxidation in contrast to VC and Au/C.