Upcycling Plastic Waste for Dual Applications in Glucose Sensing and Energy Storage

Plastic waste management and the fabrication of low‐cost, high‐performance energy storage and glucose‐sensing devices are the need of the hour. This work focuses on the deposition of nickel–phosphorus (Ni–P) thin films via an ecofriendly and cost‐effective electroless deposition method on waste plastic substrates obtained from used beverage cups. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) are used to investigate the surface morphology and roughness of the deposited film, respectively, revealing uniform deposition and a root‐mean‐square (RMS) roughness of 67.17 ± 14.5 nm. X‐ray diffraction (XRD) analysis confirmed the amorphous nature of the film. Electrochemical studies demonstrated outstanding glucose‐sensing performance of the fabricated flexible electrode with a high glucose sensitivity of 1.43 mA/cm 2 ·mM and a low limit of detection of 74.86 µM within a linear range of 0.2–2 mM, along with excellent selectivity in the presence of common interfering species. Additionally, the electrode showed impressive energy storage performance for supercapacitor applications, achieving a maximum specific capacitance of 571.43 F/g at a current density of 1 mA/cm 2 with exceptional stability. These findings highlight a sustainable and scalable route for transforming waste plastics into high‐value functional materials for next‐generation flexible electronics.