First-principles Prediction of Enhancing Graphene-Al Interface Bonding by Si-Doping

The graphene-Al interface was a physical bond with low strength, which could not realize the load transfer performance of graphene. When there were vacancies defects on the surface of graphene, the graphene easily interacted with the Al matrix to form the brittle phase Al₄C₃, which was also hoped to be avoided in the preparation of composites. In order to improve the strength of the graphene-Al interface while avoiding the interfacial reaction, this paper studied the physical properties of the Si-doped graphene-Al interface. The Si-doped graphene-Al interface had a higher bonding strength. When the doping content was 6%, the adhesion energy was increased by about 5 times compared with the graphene-Al interface. At the same time, when Si atoms were doped into the vacancies of graphene, the bonding mode of the interface changed from C-Al bonds to Si-Al bonds. This prevented the C atoms around the vacancies from easily reacting with the Al matrix. This research could provide an effective method to modify the graphene-Al interface to improve the mechanical properties of graphene/Al composites.