Highly Conductive, Large-Scale Liquid Metal Asymmetric Films by Reconfiguring Hydrogen Bonds for Versatile Electronic...

Flexible, multifunctional large-area liquid metal (LM)-based electronic skins hold great promise, yet they often require low-efficiency manual activation to achieve conductivity. A room-temperature self-sintering strategy using biomass nanofibers, such as cellulose nanofibers, offers unique advantages for the scalable fabrication of conductive LM-based films. Herein, we present a uniform, large-scale, asymmetric conductive LM film that integrates multifaceted radiative thermal management, impressive electromagnetic protection, and excellent infrared camouflage. The customized hydrogen bond acceptor, poly(vinyl alcohol), is introduced to reconfigure intermolecular hydrogen bonds, enabling the formation of flat and crack-free conductive films on arbitrarily large substrates without curling or shrinkage. Under localized capillary force, the gravity-settled LM particles are sintered into an integrated conductive area at the bottom of films, which is responsible for their exceptional metallic conductivity of 5.2 × 10⁵ S m^-1, higher than most LM films prepared by traditional sintering methods. As a proof of concept, by laminating a low-thermal-conductivity polymer side onto skin, we demonstrate the excellent radiant heat retention and low-voltage (≤0.4 V for human body temperature, lower than most reported and commercial Joule heaters), biocompatible Joule heating performance for superior human thermal management in cold environments. Additionally, the highly conductive LM layer provides dynamically stable, efficient electromagnetic interference shielding (>100 dB) and infrared stealth capabilities. Particularly, the proposed hydrogen bond acceptor is versatile and compatible with various polymers (e.g., sodium alginate and poly(acrylic acid) ). This work lays a promising foundation for scalable manufacturing of high-performance, all-in-one electronic skins.