Fabrication And Performances Investigation Of Pd/MnO₂/C Air Electrode Catalyst For Lithium-air Battery

In recent years, global energy crisis and environmental destruction situation isworsening, and the development of efficient and clean energy sources has becomeimperative. The secondary battery as an energy converter plays an important role in theprocess of the economic growth. Metal-air batteries, especially lithium-air battery hashigh energy and environmentally friendly features, of which the theoretical energydensity of up to3457Wh/kg, far more than any other secondary batteries. However,the practical application of research is still in the exploratory stage.In this study, the method of oxidation-reduction, precipitation and hydrothermalare three ways to synthesis a series of different crystal structure of nanometer MnO₂and Manganese Oxide as the catalysts. Highly dispersed cathode catalyst materials ofPd/C and Pd/MnO₂/C for lithium-air battery were prepared by microwave-assistedglycol. The structure and morphology of the catalyst materials were characterized andtheir electrochemical performances were tested. The different factors which affect theperformances of the batteries, such as the catalyst for carbon load, the dischargecurrent density, depth of discharge and the type of the electrolyte were investigated.Nano-MnO₂was synthesized by hydrothermal have shown the smaller particlesize of30nm, and the nanorod length is several μm. Catalyst MnO₂/C with Carbonload10%showed the best electrochemical performance, which the first dischargecapacity is597mAh/g, in which ionic liquid is the electrolyte. After seven cycles,discharge capacity fade quickly.The catalyst of Pd/C and Pd/MnO₂/C are prepared by the microwave assistedglycol. The discharge performance has significantly improved because Pd was added.The discharge plateau kept stability in2.7².9V, and the open circuit voltage was2.9³.1V, which reached the theoretical value. The battery has a relatively highdischarge capacity even if applying the discharge high current （0.10mA/cm2）. Thedischarge capacity was1455mAh/g when Pd/C was as the cathode catalyst; and thedischarge capacity was1510mAh/g when Pd/MnO₂/C was as the cathode catalyst.