Nature-inspired Green Supercapacitors: Advantages and Limitations

Abstract

Supercapacitors are energy storage devices with a long cycle life that can harvest and deliver energy at high power density. This makes them attractive for a broad range of high-power applications including wearable and portable electronics. Lightweight and flexible supercapacitors can provide fast charge–discharge kinetics, stretchability, and mechanical flexibility with long cycle lives. Nevertheless, conventional materials used in supercapacitors typically fall short in flexible and stretchable device fabrication. This review summarizes the recent developments in novel supercapacitors inspired by the mechanical flexibility and energy storage performance of species that exist in nature. We first provide a brief introduction to the fundamentals of light-weight supercapacitors with high mechanical flexibility. Then, we discuss the recent developments in nature-inspired supercapacitor design, highlighting the main strategies that include synthesis of nature-inspired active electrode materials and replacement of rigid device components with their bioinspired soft and stretchable counterparts. Next, we provide a summary of nature-inspired strategies used for electrode fabrication and highlight nature-inspired self-healing supercapacitors. Finally, we discuss the current limitations and future outlook for designing nature-inspired supercapacitors.