Defect-engineered MnO2 enhancing oxygen reduction reaction for high performance Al-air batteries

More recently, defect-engineering has been demonstrated as a facile but effective route to boost electrocatalytic performance. In this work, an activity-enhanced MnO2 catalyst with abundant oxygen vacancies and edges is developed by Ar-plasma strategy to enhance the electrochemical performance of Al-air batteries. Based on the detailed morphology and structure analysis, rich defects are successfully induced on the surface of MnO2 nanowires, and the defect-engineered MnO2 catalyst displays higher activities (more positive reduction potential and larger reduction current density) towards oxygen reduction reaction (ORR) compared with pristine MnO2. However, excessively high defects can work against the ORR catalytic enhancement due to the structure distortion. The resultant Al-air battery displays higher voltage, larger power density and better durability. The remarkable ORR activity is due to the formation of defective active sites, which is beneficial for the oxygen species adsorption and activation of O-O bond, confirmed by density function theory (DFT) calculation. This strategy represents a new route for the development of non-noble electrocatalyst for Al-air batteries.