Ruthenium Oxide Modified alpha‐Manganese Dioxide Nanotube as Efficient Bifunctional Cathode Catalysts for Lithium Oxygen Batteries

Abstract

AbstractThe design and fabrication of cathode remain a major challenge for lithium oxygen (Li‐O2) batteries. Here, RuO2/α‐MnO2 nanotubes as efficient bifunctional cathode catalysts are prepared by two‐step hydrothermal reaction to improve the battery performance. Nitrogen adsorption desorption (BET) tests indicate that RuO2/α‐MnO2 nanotubes have mesoporous structure with specific surface area of 51.2 m2 g−1. Electrochemical tests show that the catalytic activity and the conductivity of α‐MnO2 nanotubes modified with RuO2 nanoparticles are improved. RuO2/α‐MnO2 nanotubes are used as a bifunctional electrocatalyst for cathode in Li‐O2 batteries, which show reduced overpotential, improved rate and cycling performance. At the current density of 0.05 mA cm−2, the overpotential of the batteries can go down by 0.38 V, and these batteries can be fully discharged/charged 26 cycles stably at a fixed capacity of 500 mAh g−1. The combination of RuO2 nanoparticles and α‐MnO2 nanotubes has excellent catalytic activity for ORR/OER, thus greatly improving the electrochemical performance of Li‐O2 batteries.