Strong yet tough graphene/graphene oxide hybrid films

Freestanding graphene films (GFs) have attracted extensive attention due to outstanding properties. Nevertheless, GFs show poor mechanical property because of lacking inter-laminar bonding although thermal conductivity is fascinating. Graphene oxide (GO), derivative of graphene, can act as glue to adhere different substrates depending on functional groups to boost connection between substrates. Here, we prepared GO/graphene hybrid films using GO to improve the strength by Meyer method. When GO concentration increases, the tensile strength is ever enhanced from 8 to 90 MPa, which was further increased after annealing at 1500 °C. Meanwhile, the film shows excellent fracture toughness, the toughness was improved to 0.86 MJ/m3 when GO increases to 50 wt%. After 5000 cycles, the films still demonstrate excellent fatigue property and flexibility performance. Furthermore, the hybrid films show excellent electromagnetic interference shielding effectiveness (above 60 dB at 8–12 GHz). Although the annealing temperature is as low as 1500 °C, its thermal conductivity of the hybrid film with GO loading of 50 wt% still remains 600 W m−1K−1. Our hybrid strategy provides a new way to achieve multifunctional graphene films at low annealing temperature, which is promising in flexible device application.