Ruthenium oxide modified alpha‐manganese dioxide nanotube as efficient bifunctional cathode catalysts for lithium oxygen batteries

The design and fabrication of cathode remain a major challenge for lithium oxygen (Li‐O${}_2$) batteries. Here, RuO${}_2$/α‐MnO${}_2$ 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 RuO${}_2$/α‐MnO${}_2$ nanotubes have mesoporous structure with specific surface area of 51.2 m${}^2$ g${}^{-1}$. Electrochemical tests show that the catalytic activity and the conductivity of α‐MnO${}_2$ nanotubes modified with RuO${}_2$ nanoparticles are improved. RuO${}_2$/α‐MnO${}_2$ nanotubes are used as a bifunctional electrocatalyst for cathode in Li‐O${}_2$ 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 RuO${}_2$ nanoparticles and α‐MnO${}_2$ nanotubes has excellent catalytic activity for ORR/OER, thus greatly improving the electrochemical performance of Li‐O${}_2$ batteries. (© 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)