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O: Fachverband Oberflächenphysik
O 67: Solid-Liquid Interfaces III: OER, ORR, CO2RR, etc.
O 67.8: Vortrag
Mittwoch, 18. März 2020, 12:30–12:45, WIL C107
Oxygen reduction by doped graphene in Li-air batteries — •Elmar Kataev1, Daniil Itkis2, Alina Belova2, Carlos Escudero3, Virginia Pérez-Dieste3, Axel Knop-Gericke4, and Lada Yashina2 — 1Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Erlangen, Germany — 2Department of Chemistry, Moscow State University, Moscow, Russia — 3ALBA Synchrotron Light Source , Barcelona, Spain — 4Fritz-Haber Institute of the Max Planck Society, Berlin, Germany
Oxygen reduction reaction (ORR) plays a key role in lithium-air batteries (LABs) that attract great attention thanks to their high theoretical specific energy. Because of high surface area and electric conductivity, various carbons are often materials of choice for applications as the LAB cathode. Unfortunately, the practical applications of LAB batteries are impeded by poor rechargeability, associated with ORR side reactions. Recently it was shown that doping of carbon materials could change its catalytic activity and potentially reduce reactivity towards ORR products. However, the mechanisms of doped-carbon reactivity in LAB are still unclear. Here we report a direct photoemission study of ORR pathway on pure, nitrogen-, boron- and oxygen- doped graphene. We designed the electrochemical cell with two-layer graphene transferred on glass-ceramics electrolyte to avoid side reactions of ORR products with liquid electrolyte. Combining operando photoemission data with in situ observation of superoxide anion attack on graphene in model chemical systems, we reveal the impact of impurities in carbon on its reactivity in ORR.