"One for two" strategy of fully integrated textile based supercapacitor powering an ultra-sensitive pressure sensor for wearable applications

Textile-based energy storage devices help realize the full potential of flexible electronics as they combine the functionality of wearable devices with the inherent high-power density and fast charging/discharging capability of supercapacitors. In this work, Nickel di-selenide (NiSe2) is grown on carbon cloth (CC) via a facile one-pot hydrothermal technique and is used for supercapacitor and pressure sensor to demonstrate a textile-based fully integrated system. In a three-electrode configuration, the NiSe2 electrode produces a half-cell specific capacitance of 980 Fg(- 1) at 1 Ag-1, indicating its high-rate capability. Further, the NiSe(2 )electrode is combined with activated carbon (AC) electrodes generated from biomass to construct an asymmetric supercapacitor device (ASC) with a 1.6 V of output voltage. The ASC device delivers maximum specific energy of 50 Whkg(-1 )at a current density of 1 Ag-1 and a maximum specific power of 900 Wkg(-1) at 10 Ag (-1). An ultra-sensitive pressure sensor is fabricated by sandwiching the NiSe(2 )grown carbon cloth between thin layers of PDMS, which exhibits a sensitivity of 0.91 kPa(-1 )in the wide dynamic pressure range of 1- 80 kPa(-1). An exceptional mechanical stability is obtained for an unloading/loading of 1 kPa of pressure for 5000 cycles. Further, it is powered using the NiSe2/ CC || AC/CC AFSC for steady and reliable detection of radial pulse pressure on the human wrist in real-time. This work paves a new path in exploring the potential of textiles when combined with nanomaterials to develop low-cost, self-powered healthcare systems for real-time monitoring of health parameters.