Valorization of Waste Plastic as a Flexible Electrode for Electrochromic Applications

Modern technological advancements have greatly improved human life, but at a high environmental cost. Plastic packaging has become nearly ubiquitous, leading to excessive plastic waste generation. Although recycling efforts are widespread, they are often energy-intensive and not always cost-effective. Consequently, there is a growing research interest in repurposing plastic waste into value-added functional materials. In this work, plastic substrates obtained from used beverage cups are used as a substrate for electrochromic electrodes via a simple one-pot electroless deposition and an electrochemical conversion method. This simple, redox-driven, and scalable synthesis method enables the direct deposition of a conductive and electrochromic Ni thin film on a flexible substrate obtained from waste plastic cups. The fabricated electrode exhibits a uniform microspherical morphology, offering a high surface area that enhances its electrochemical performance. The electrode demonstrates excellent electrochromic properties, including fast switching speeds of a few seconds between colored and bleached states with excellent cycling stability. Furthermore, by integrating the conductive and electrochromic functions into a single layer, this approach simplifies device architecture and improves charge transport. This study presents a sustainable and cost-effective strategy for upcycling plastic waste into high-performance electrochromic materials.