From trash to treasure: crafting electrochemical supercapacitors with recycled waste materials

Over the past few decades, there has been a massive increase in research focused on the global need for renewable energy sources. Numerous studies and reports in the literature have been conducted on technologies like wind and solar energy. However, partly due to expense and the difficulty of providing service during off-peak hours, these technologies have not been widely used all over the world. Over the past several decades, research on energy storage systems has increased to make such systems more competitive and advanced. This envisions formulating an energy storage system with cost-efficient power storage during off-peak hours for later distribution. A supercapacitor (SC) is an example of energy storage and delivery technology that accumulates and transfers energy rapidly, providing a considerable amount of current for a short time. SC technology research and development have proliferated during the last ten years. In particular, this review highlights the advancements made in SCs to provide solutions to problems associated with solid waste management (SWM) and energy usage. It begins with the introduction to SCs, wastes, SWM, waste hierarchy, and essential waste products that can be utilized to fabricate the electrodes of SCs. A brief discussion is made regarding recycling and concern for environmental pollution. Prominent recycling techniques and materials have been overviewed, followed by the performance of such waste products-derived SC electrodes. The summary concludes with the authors' views and discusses the future scope and unstated challenges.