Sustainable 3D Structural Binder for High‐Performance Supercapacitor by Biosynthesis Process

Abstract Flexible supercapacitors represent an attractive technology for the next generation of wearable consumer electronics as power sources but usually suffer from relatively low energy density. It is highly desired to construct high‐performance electrodes for the practical applications of supercapacitors. Here, inspired by the natural structure of the spider web, an elaborate design of binder is reported through a biosynthesis process to construct flexible electrodes with both excellent mechanical properties and electrochemical performance. Through this strategy, a spider‐web‐inspired 3D structural binder enables large ion‐accessible surface area and high packing density of active electrode material as well as efficient ion transport pathways. As a result, a high areal capacitance of 4.62 F cm^‐2 and a high areal energy density of 0.18 mW h cm^‐2 is achieved in the composite electrodes and symmetric supercapacitors, respectively, demonstrating a promising potential to construct flexible energy storage devices for diverse practical applications.