Monolithic Integration of All‐in‐One Supercapacitor for 3D Electronics

Abstract A supercapacitor is usually stacked in the configuration of a layered sandwiched architecture, and has been adopted as discrete energy storage device or circuit component. However, this stacked structure decreases mechanical integrity, leads to low specific capacity, and prevents high‐density monolithic integration. Here all‐in‐one supercapacitors are fabricated by integrating cathode, anode, current collector, and separator into one monolithic glass fiber (GF) substrate together with other circuit components through matured and scalable fabrication techniques, the all‐in‐one supercapacitor is embedded as a component for 3D electronics. This all‐in‐one architecture demonstrates its effectiveness in the prevention of the delamination of the sandwiched supercapacitor and the minimization of the proportion of inactive materials. The supercapacitor delivers high power density (320 mW cm⁻³) and energy density (2.12 mWh cm⁻³), and exhibits a capacitance retention of 100% even after a continuous cycling of 431 h. Furthermore, a 3D polydimethylsiloxane/GF architecture is constructed for driving a flash light emitting diode system, where the all‐in‐one supercapacitor is monolithically integrated in the 3D system, and each layer is connected via vertical through‐holes. This all‐in‐one device can be constructed with a macroscopically available membrane and readily integrated into 3D systems without secondary packaging, providing the potential for high‐density heterogeneous 3D electronics.