Liquid Metal Aerogel With Janus Architecture for Selective Direction Recognition and High‐Efficiency Moisture Energy Harvesting

Abstract Liquid metal (LM) micro‐nano droplets show the superiority in reducing the high surface tension applicable in conductive inks for flexible electronics. However, the dynamic surface makes LM droplets susceptible to be oxidized, facing challenges in storage and applications. Herein, a bifunctional groups cross‐linking strategy is adopted to encapsulate LM droplets into a robust shell. During sonicating LM in carboxymethyl chitosan (CMCS) solution with bifunctional groups (i.e., carboxyl and amino groups), a robust interface shell is constructed by anchoring effect, thereby providing high chemical stability (>7d). When directionally freezing‐drying LM dispersions, aerogel with Janus architecture is produced driven by the gravity of LM droplets. Due to the unique heterogeneous structure, the resultant aerogel exhibits a selective multifunctional response toward directional bending. In addition, owing to the gradient distribution of CMCS within aerogel, moisture electricity generator can be built with a high output voltage of 460 mV. Thus, this bifunctional groups cross‐linking strategy not only improves the chemical stability of LM micro‐nano droplets, but also renders a new method for producing multifunctional aerogel with energy harvesting and selective directional recognition, and applicable in smart sensors and power supplying devices.