Sustainable electromagnetic shielding graphene/nanocellulose thin films with excellent joule heating and mechanical properties via in-situ mechanical exfoliation and crosslinking with cations

Herein, a sustainable graphene/nanocellulose electromagnetic shielding composite film was fabricated via nanocellulose inducing graphite in-situ mechanical exfoliation. Cations were added to enhance properties of the films via cation crosslinking. The few-layer graphene produced by this strategy was ∼3.4 nm in average thickness and good dispersion in the films. The electrical conductivity, electromagnetic shielding effectiveness and mechanical property of the film were enhanced by cation crosslinking, while cation-π interactions between metal and graphene-enhanced the electrical conductivity and electromagnetic shielding effectiveness. For example, the films cross-linked Cu2+ cations exhibit a tensile strength of 64.3 MPa, elongation at broken of 17.1%, and electromagnetic shielding effectiveness of 30.7 dB and a conductivity of 3172 S/m at a thickness of 40 μm. In addition, the different Joule heating performance and electromagnetic shielding effectiveness were found in the films by cross-linking with different cations. We provide a new route to prepare low-cost, sustainable, and tunable electromagnetic shielding films with good Joule heating and mechanical property.