Printed Flexible WO ₃ ‐Based Supercapacitors for Powering Low‐Powered Electronics in Wearable Devices and Energy Autonomous Temperature Monitoring

ABSTRACT Wearable electronic systems require flexible and manufacturable energy storage devices that can be integrated with printed sensors and electronics. In this work, a flexible supercapacitor (FSC) is fabricated by direct screen printing of WO 3 electrodes, providing a scalable and manufacturing‐compatible route for WO 3 ‐based flexible electrochemical energy storage devices. The screen‐printed WO 3 ‐based FSC exhibits stable charge‐storage behavior with contributions from electric double‐layer capacitance (47.22%) and pseudocapacitive processes (52.78%). The device delivers a specific capacitance of 3.44 F g −1 (18.58 mF cm −2 ) at 0.05 mA, decreasing to 2.25 F g −1 (12.19 mF cm −2 ) at 0.5 mA, indicating good rate capability. An energy density of 0.302 Wh kg −1 and a power density of 3.68 W kg −1 are achieved at 0.05 mA. The FSC maintains consistent electrochemical performance under mechanical deformation at bending angles of 0°, 15°, 25°, 35°, and 45°. Finally, the FSC is integrated with a solar cell and a temperature sensor to demonstrate energy‐autonomous wearable temperature monitoring.