Breaking Thermal Conductivity–Electrical Resistivity Trade‐Off in Liquid Metal–Based Thermal Interface Materials via Interface Engineering

ABSTRACT Liquid metal–based thermal interface materials offer superior thermal conductivity and fluidity but are limited in practical applications by their inherently low electrical resistivity. Here, we present an interface engineering strategy that overcomes this fundamental trade‐off, enabling the synthesis of GaIn‐B featuring a bimodal particle size distribution. This structure simultaneously exhibits a non‐contact network feature that effectively prevents electrical percolation while maintaining efficient thermal transport. GaIn‐B exhibits a significant thermal conductivity of approximately 16 W m −1 K −1 and an electrical resistivity exceeding 10 11 ohm cm. We developed a phenomenological model based on effective medium theory to quantitatively describe and predict the critical conditions for breaking the thermal–electrical trade‐off. The simplicity and scalability of the GaIn‐B synthesis process enable kilogram‐scale production, making it highly suitable for industrial applications.