P-type doping of lithium peroxide with carbon sheets

Abstract

The interaction of lithium peroxide (Li2O2) with carbon electrodes in Li-air batteries is studied with model systems of graphene-intercalated Li2O2, using density functional theory (DFT) methods. Although both the Li2O2 bulk and its stoichiometric surface structures (without single O atoms) are insulating, the incorporation of graphene sheets into the Li2O2 introduces hole states in the oxygen orbitals due to the electron transfer from the anti-bonding O2 orbitals to the graphene sheets. This indicates that carbon sheets not only provide conducting channels by themselves, but they also open new channels in Li2O2.