Solid Particle‐Liquid Metal Mixtures for Robust High‐Current Interconnects in Stretchable Electronics and Soft Robotics

ABSTRACT Electromigration and thermal degradation limit the reliability of interconnects in stretchable electronics and soft robotics, particularly in room‐temperature liquid metals (LMs), where weaker interatomic bonds accelerate failure at lower current densities. To address this, we created solid particle‐LM mixtures that incorporate metallic (iron and tungsten) and non‐metallic (glass) particle fillers, which suppress electromigration and thermal degradation. These LM mixtures are able to achieve a maximum current density exceeding 2.5 10 (80% improvement over unfilled LM) while extending operational lifetimes by under a constant DC current density of 1.1 10 . Despite a small decrease in electrical conductivity at higher filler loadings, the LM mixtures retained their fluidic properties, which are critical for integration in soft matter systems. Furthermore, the low particle loading (5 vol.%) enhanced Joule heating performance, enabling electrothermal actuators to achieve faster actuation speeds and higher cyclic frequencies compared to their pure LM counterparts. By increasing the electrical stability through solid particle fillers, this facile strategy offers a scalable pathway toward robust, high‐current LM interconnects for next‐generation stretchable electronics and soft robotic systems.