Aramid nanofiber assisted preparation of self-standing liquid metal-based films for ultrahigh electromagnetic interference shielding.

• A self-standing liquid metal-based film was prepared for EMI shielding. • The resultant liquid metal-based film achieved a remarkable electrical conductivity of 7752 S/cm. • The EMI SE of the liquid metal-based film could reach 78.2 dB at a tiny thickness of 20 μm. • The liquid metal-based film possessed excellent reliability and superior thermostability. Liquid metals (LM) have a high potential for Electromagnetic interference (EMI) shielding application, due to their soft feature and excellent electrical conductivity. However, it still remains a huge challenge to fabricate a self-standing LM film for EMI shielding, due to the liquid feature of LM. Herein, we designed a self-standing LM-based film by incorporating minute quantities of aramid nanofiber (ANF) to construct a supporting framework via vacuum filtration. Due to the formation of highly conductive LM networks, the resulting LM/ANF film achieved a remarkable electrical conductivity of 7752 S/cm. The promising electrical conductivity endowed the LM/ANF film with an extremely high EMI shielding effectiveness (EMI SE) of 78.2 dB at a mere 20 μm thickness. The LM/ANF film also possessed excellent reliability and superior thermostability, without an obvious decline in the EMI SEs after 5000 folding cycles and thermal treatment (250 °C) for 20 h, respectively. This study offers a novel design strategy to develop ultrathin EMI shielding films combined with high reliability and thermostability for application in modern high-power electronic devices. [ABSTRACT FROM AUTHOR]