Jujube-cake inspired lightweight and flexible MXene/liquid metal/bacterial cellulose electromagnetic interference shielding film with excellent Joule heating and thermal conductivity

The modern 5G communication electronics and systems require lightweight and flexible films that have superior electromagnetic interference (EMI) shielding performance as well as high thermal conductivity. This work reports a facile "one-pot" synthesis strategy to create EMI shielding films with a structure inspired by "jujube cake". The two-dimensional Ti3C2Tx MXene nanosheets were combined with one-dimensional bacterial cellulose (BC) to form a mechanically entangled supporting framework resembling the structure of a "sponge cake", wherein zero-dimensional liquid metal (LM) droplets like "jujubes" were ingeniously introduced. A series of multifunctional Ti3C2Tx/LM/BC (TLB) EMI shielding films with highly efficient conductive networks and complete thermal conductivity pathways were prepared through a simple, eco-friendly and highly scalable fabrication process involving vacuum-assisted filtration and hot pressing. Such ultrathin (18 μm) and lightweight (0.63 g cm−3) TLB composite film demonstrates an outstanding specific SE (SSE/t) of 21695.8 dB cm2 g−1. Meanwhile, it exhibits a remarkable in-plane thermal conductivity of 10.44 W m−1 K−1 and exceptional Joule heat performance from room temperature to 95 °C at 3.0 V in seconds. These attractive properties and scalable fabrication of TLB composite film showcase its potential in the realm of flexible electronics, particularly for applications pertaining to EMI shielding protection, electromagnetic compatibility and thermal management.