Free standing flexible graphene oxide + α-MnO2 composite cathodes for Li–Air batteries

Abstract

The most important factor regarding to influence the electrochemical performance of lithium–air battery is to choose an effective catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this study, α-MnO2 (manganese oxide) nanowires were used as an active electrocatalyst synthesized by microwave hydrothermal method. Graphene oxide (GO) and α-MnO2 nanowires were combined to obtain free standing paper cathodes and α-MnO2+GO free standing paper cathodes were produced with dispersing different amounts of α-MnO2 nanowires (10 wt.%, 30 wt.%, 50 wt.%, and 70 wt.%) by using vacuum filtration method. The morphologies and structures of cathodes are evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. The electrochemical tests were carried out at the voltage window between 1.0 and 4.5V in ECC-Air test cell. α-MnO2+GO composite paper containing 70wt.% α-MnO2 catalyst showed the highest specific discharge capacity value of 2900mAhg−1. Moreover, the experimental findings showed that dispersing of α-MnO2 catalyst in GO structure results in remarkable improvement of the electrochemical performance of Li–air battery cathodes.