Oxygen modification enhanced bonding behaviors in Cu/graphene interface: First principles calculations

Oxygen modification on the interface is crucial to improve the mechanical strength of graphene/copper (Gr/Cu) composites. However, the existing form of interface oxygen and the strengthening mechanisms are not well understood. In this work, first principles calculations are performed to investigate the mechanisms for oxygen modification in the Gr/Cu interface and the influences on the bonding behaviors. It is found that oxygen modification could increase the separation work of the Gr/Cu interface by about 300 %, and thus enhance the interface bonding substantially, owing to the formation of strong ionic bonds between O and Cu. As a result, the theoretical tensile strength is increased from 3.29 GPa to 4.67 GPa by 42 %. Changes in charge density and atomic spacing at the interface during stretching suggest that fracture occurs along the interface between graphene and O. This study provides valuable insights into the design of high-strength Gr/Cu composites.