Amine-functionalized graphene and its high discharge capacity for non-aqueous lithium–oxygen batteries

Abstract

Amine-functionalized graphene was synthesized via a one-step solvothermal method and used as a metal-free cathode for non-aqueous lithium–oxygen batteries. The material delivered an outstanding specific capacity of 19,789 mAh/g at a current density of 200 mA/g as well as better cycling stability than graphene without the amine functional group. This improvement was attributed to the electron-donating effect of the amine groups and appropriate mesopore volume, which can promote the penetration of oxygen, electrons, and lithium ions, as well as accommodate more discharge products, Li2O2 in Li–O2 batteries. Amine-functionalized graphene has an amine functional group on the carbon surface, which improves the electrical conductivity of carbon and provides electrochemical active sites for oxygen absorption reactions.