All‐Natural, Stretchable, and Ionically Conductive Biogels Enabled by Crowded Intermolecular Interactions for Sustainable Electronics and Robotics

ABSTRACT Stretchable devices have driven technological advances across diverse fields, including medical sensing, electronic skins, and soft robotics. However, achieving high‐performance stretchability often depends on toxic manufacturing, costly syntheses, and petrochemical materials, which conflict with sustainability goals. Here, we present a highly stretchable yet entirely natural biogel fabricated through a simple and environmentally benign process. Despite being derived from low‑cost, food‑grade, and fully biodegradable constituents, our biogel integrates dense intermolecular interactions to achieve a combination of top‐performing attributes, including stretchability (∼700%), Young's modulus (∼1.3 MPa), fracture strength (∼2.8 MPa), burst pressure (∼900 mbar), ionic conductivity, and optical transparency. Its mechanical properties remain stable even after 30 days and in subzero temperatures. We showcase its versatility in various applications that demand high stretchability, including deformable sensors for falling object detection, smart electronic fibers for sign language detection, stretchable pneumatic grippers for handling fragile objects, and crawling robots that can serve as plant seed carriers. Our biogel offers a low‐cost, sustainable alternative to traditional petrochemical‐derived elastomers, opening new possibilities for transient, biodegradable soft devices.