Wireless powered asymmetric textile supercapacitors for continuous supply of energy in smart wearable systems

We developed an autonomous energy supply system for wearables using radio-frequency (RF) wireless power transfer (WPT) integrated with a textile supercapacitor (TSC) and implemented it in a helmet. For this, we initially developed a new interdigitated electrode-based TSC using a metal oxide/graphene composite. The electrochemical characterisations show that the developed TSC exhibits an excellent specific capacitance of 72 mF cm −2 at a scan rate of 1 mV s- 1 . Further galvanostatic charging-discharging analysis reveals that at a current density of 0.277 mA cm −2 , the TSC exhibits a specific capacitance of 16.8 mF cm −2 , and the TSC device retains 72.7% of its capacity after 3000 cycles. For a continuous energy supply, we designed an RF energy harvesting system incorporating a rectenna with a dipole receiving antenna and a voltage doubler rectifying circuit. The integration of TSC with WPT reveals that the rectenna's ability to harvest energy at and stored in TSC. The stored energy was used to directly power a red LED at 1.72 V and 4.8 mA. Illumination lasted 7.2 s, during which 89.2 mJ was delivered, giving a discharge efficiency of 97.3%. The integrated TSC with WPT offered the advantage of wearability in remote environmental and sports/healthcare applications. • Development of energy autonomous systems using supercapacitor and WPT. • Textile supercapacitor developed and exhibited capacitance of 72 mF cm −2 . • For a continuous energy supply, we designed an RF energy harvesting system. • WPT with energy storage offered in remote environmental and sports/healthcare applications.