Colloidal Manganese Oxide Nanoparticles as Bifunctional Catalysts for Oxygen Reduction and Evolution Reactions in Lithium/Air Batteries

摘要

A main challenge concerning the Li/air battery system is the search for bifunctional cathode catalysts for the oxygen reduction (ORR) and oxygen evolution reactions (OER) during discharge and charge, respectively. Furthermore, a replacement of noble metal catalysts by metal oxide nanoparticles is necessary for cost reduction. The main problem of the system, however, is the decomposition of the electrolyte during cell cycling, so that most of the previous studies on ORR/OER catalysts only reported the catalytic activity for electrolyte decomposition. Therefore, a stable electrolyte is required before any catalyst investigation can be carried out. Here we report on BMP-TFSI as electrolyte solvent and the effects of the addition of LiTFSI as conducting salt and DMSO as superoxide- and Li ion-coordinating solvent additive, which are investigated via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The catalytic activity of the Mn304 particles synthesized via colloidal synthesis is evaluated by CV measurements.