Bacterial cellulose-based composite films with liquid metal/graphene synergistic conductive pathways for superior electromagnetic interference shielding and Joule heating performance

Modern integrated electronics are in great demand for high-performance electromagnetic interference (EMI) shielding materials with exceptional mechanical properties. Liquid metal (LM) has demonstrated great potential in EMI shielding by its superior electrical conductivity. However, its real-world EMI application is limited by the poor compatibility, insulating oxide shells, and unpredictable leakage. Here, graphene oxide (GO) is used to encapsulate LM to form LM@GO microdroplets dispersion, and bacterial cellulose (BC) is applied to construct a biocompatible fabric network. Moreover, GO is in-situ reduced by hydrazine vapor, which generates synergistic LM/reduced graphene oxide (rGO) conductive pathways with the aid of roll-in process, obtaining flexible LM/rGO/BC (LGB) composite film with outstanding electrical conductivity of 4.5 × 104 S/m and exceptional shielding effectiveness of 64.0 dB. The rGO sheets and BC network demonstrate layered structure after roll-in process, effectively impeding the leakage and oxidation of LM and achieving a tensile strength up to 62.9 MPa of LGB films. Meanwhile, the LGB films exhibit exceptional Joule heating performance, and the stable surface temperature reaches 110 °C with high stability and reliability when the applied voltage is 4 V. This work provides a feasible engineering approach to prepare LM-based films for applications in EMI shielding and wearable electronics.