Size-adjustable, foldable, and stretchable capacitor with origami and auxetic structure

Abstract

Stretchable and flexible capacitors offer significant advantages as energy devices for next-generation electronics. In line with the trend for the aforementioned electronic devices, scientists are exploring the development of energy devices using intrinsically stretchable materials to endow geometrical flexibility. However, these materials typically exhibit a positive Poisson’s ratio, which may not be favorable for long-term mechanical stability. In this study, a size-adjustable capacitor is presented, featuring an auxetic and origami structure designed for foldability and stretchability. The combined structural strategy of auxetic and origami allows the device to be folded and stretched without a deterioration in performance. The size of this auxetic capacitor can be modified into five different stages: 100 % and 50 % folded, original, and 50 % and 100 % stretched. To assess the stability of the device under mechanical deformations and long-term usage, multiple characterization tests were conducted, including cyclic voltammetry and charge−discharge tests, demonstrating stable performance under mechanical deformations. This promising size-adjustable capacitor can find applications in a wide range of devices, including wearables and compact electronics.