Integration of patterned electrolyte film and sacrificial substrate serpentine electrode of low curvature for high stretch supercapacitor, physiological signal detection

Abstract

Optimizing electrode structures is a promising solution for wearable electronics and flexible power sources. Nevertheless, there are still significant challenges in how to get rid of the constraints of the substrate and electrolyte on the electrode structure, thereby reducing the impact of such constraints on the elongation of supercapacitors and stabilizing the electrochemical output. In this work, a serpentine structure of low curvature (SSLC) was designed and fabricated by comparing the effect of the curvature of the turning structure on the performance of the serpentine structure. The superiority of SSLC electrodes over existing electrode structures is verified using finite element analysis (FEA) and stability experiments. Further, the SSLC electrode is used for physiological signal detection (ECG, EMG, GSR), showing excellent stability and low electrode–skin contact impedance, which is better than the medical wet electrode. A high-stretch supercapacitor (SSC) was prepared by sacrificing the substrate of the SSLC electrode and integrating the patterned electrolyte film. When the scan rate is 10 mV·s−1, the area specific capacitance of SSC is as high as 197.9 mF·cm−2. Under extreme deformation conditions (stretch 100%, bend 180°, twist 180°) SSC can maintain stable output. And after 10,000 charge–discharge cycles, the SSC can still output 91.96% of the initial power stably, indicating that the prepared SSC has high stretchability and stability. With highly stretchable and stable low-curvature serpentine structure electrodes, the SSC coupled with patterned electrolyte films and sacrificial substrate electrodes in this paper offer a promising solution for stretchable flexible power supplies and wearable electronics.