Flexible energy storage patch based on NiPS3/graphene zinc-ion hybrid supercapacitor for integrated biosensors

The rapidly developing self-powered biosensor technologies require flexible, robust, and safe energy storage devices. One of the key factors of a self-powered system is the integration of energy storage device components with bio-sensors. Here, we developed a hybrid self-powered biosensor system for health monitoring comprising zinc-ion supercapacitor (ZISC) wearable patch, introducing a two-dimensional (2D) NiPS3 as a metal phosphorus chalcogenide capacitive electrode. Due to its inherent 2D nanosheet morphology, NiPS3 electrode confined with graphene (NiPS3@graphene) shows good electrochemical performance. The ZISC printed with NiPS3@graphene and zinc on cellulose substrate followed by hydrogel electrolyte results in a powerful, robust, and flexible device. It exhibits stable energy storage performance, retaining 86% capacity after 1000 charge–discharge cycles and good mechanical flexibility at different bending angles, with a retaining capacity of 97.7% compared to initial performance after 500 bending cycles. Finally, a self-powered biosensor was developed by transforming a thin and lightweight ZISC tandem device on a medical-grade cellulose patch. This patch is demonstrated to power a wearable temperature sensor with a connection via a Bluetooth module and stationary glucose sensor to establish real-time health monitoring. Our results show the significance of 2D NiPS3@graphene-based zinc-ion supercapacitors in an application as an integrated patch for powering health monitoring systems.