A self-assembled graphene/polyurethane sponge for excellent electromagnetic interference shielding performance

With the rapid development of personal computers and portable electronics, people have to get rid of a lot of unwanted electromagnetic pollution. The development of high performance electromagnetic interference (EMI) shielding materials is of critical importance to address ever-increasing military and civilian demand. Owing to its high electrical conductivity and flexible 3D structure, graphene sponge has great potential for excellent EMI shielding performance. However, its EMI shielding performance suffers from the material's poor elasticity and durability. In this paper, we demonstrate the potential of a self-assembled graphene/polyurethane sponge composite, synthesized via a two-step hydrothermal method, for EMI shielding. This kind of material exhibits a high specific EMI shielding effectiveness of 969-1578 dB cm² g^-1 which is comparable or even superior to traditional graphene/polymer sponges. The excellent EMI shielding performance originates from the superconductivity of graphene and the highly porous structure of the graphene/polyurethane sponge. It is found that the polyurethane sponge works as a robust scaffold for graphene to shape its 3D structure. This work introduces a facile yet efficient two-step hydrothermal approach to prepare a graphene/polyurethane sponge with excellent EMI shielding performance and good durability.