Synergistic Microwave Absorption and Thermal Management in Biobased LM/SiC/BNC Composite Films for Flexible Electronics

The miniaturization and high integration of modern electronics lead to concurrent issues of heat accumulation and electromagnetic interference, necessitating lightweight materials with both efficient thermal management and broadband microwave absorption. To address these challenges, multifunctional LM/SiC/BNC composite films were developed via a biobased 3D confinement and bridging synergistic strategy. Liquid metal (LM) and silicon carbide nanowires (SiC) were confined within a 3D interconnected bacterial nanocellulose (BNC) network, achieving uniform dispersion and robust interfacial coupling among the components. Due to the triphasic synergistic effect of BNC confinement, LM bridging, and SiC dielectric loss, as well as the efficient electromagnetic attenuation paths constructed by multiheterointerfaces, the composite films achieved an exceptional minimum reflection loss (RL_min) of -59.8 dB at a thickness of 5.5 mm. The effective absorption bandwidth reached 1.8 GHz, while maintaining an in-plane thermal conductivity of 1.86 W·m^-1·K^-1. This work demonstrates the synergistic enhancement of exceptional microwave absorption and efficient thermal management. Combining superior integrated performance with green processability, the developed composite films offer a practical and promising material solution for the electromagnetic and thermal protection of next-generation compact flexible electronics.