Electrochemical Activities of Electrolytic Manganese Dioxide (EMD) as a Cathode Electrode for Lithium Air Batteries

摘要

Electrolytic manganese dioxide, prepared by anodic electrodeposition, was investigated for thepossible application as cathode active material for lithium air battery. Electrolytic manganese dioxideshowed the catalytic activity by lowering overpotentials for discharge and charge reactions. FT-IR andmass spectroscopy analysis suggested that lithium carbonates compounds were the main productsformed during discharge and only a small amount of lithium oxides were produced. Furthermore,surface analysis and electrochemical impedance spectroscopy supported that discharge products werenot fully removed during charge process and, that is, discharge and charge reactions were onlypartially reversible. Measurement of electrolytic manganese dioxide mass changes during cyclicvoltammetry showed that 27.5% of discharge reduction reaction products were not removed duringcharge oxidation reaction. The remaining discharge products on air cathode disturbed the access ofoxygen reactant to the reaction sites and deteriorated the cell performance. In order to improve thecycleability of lithium air battery, the reaction mechanism of charge-discharge reaction must beelucidated to overcome the irreversibility during cycling.