Screen-printed highly stretchable and stable flexible electrodes with a negative Poisson's ratio structure for supercapacitors.

Flexible power sources are crucial to developing flexible electronic systems; nonetheless, the current poor stretchability and stability of flexible power sources hinder their application in such devices. Accordingly, the stretchability and fatigue stability of flexible power sources are crucial for the practical application of flexible electronic systems. In this work, a flexible electrode with an arc-shaped star concave negative Poisson's ratio (NPR) structure is fabricated through the screen printing process. Using the combination of finite element analysis (FEA) and tensile tests, it is proven that the arc-shaped star concave NPR electrode can effectively reduce the maximum tensile stress and increase the maximum elongation (maximum elongation 140%). Furthermore, the flexible electrodes prepared in this study are assembled into all-solid-state symmetric supercapacitors (SSCs), and their electrochemical properties are tested. The SSC prepared in this study has a high areal capacitance of 243.1 mF cm. It retains 89.25% of its initial capacity after 5000 times of folding and can maintain a stable output even in extreme deformation, which indicates that the SSC prepared in this study has excellent stability. The SSC with the advantages mentioned above obtained in this study is expected to provide new opportunities to develop flexible electronic systems.