Advances and challenges in biomass-derived supercapacitors

The rapidly increasing need to find safer and more sustainable ways to store energy has triggered the development of supercapacitors, which are currently used as highly stable, high-voltage storage systems that can charge quickly in terms of speed, deliver high power output at an impressive rate, and have an excellent lifespan. Carbon derived from biomass has become a major contender for making sustainable electrodes due to its low cost and environmentally friendly nature. This manuscript presents a comprehensive review of recent studies on the conversion of various biomass feedstocks into porous carbon materials suitable for various applications. Biomass derived carbon has exhibited competitive functions and improved performance compared to conventional activated carbons, reaching a level of specific surface areas exceeding 2000 m2/g and a specific capacitance of approximately 300 F/g. Such capacitors are therefore not only used as an energy carrier but also in flexible and wearable devices. Furthermore, this article highlights the potential of green synthesis paths in conjunction with information-controlled material design strategies, such as machine learning, to enhance the connection between structure and performance. Still, there are obstacles to enhance the production scale, unification of assessment methods, and overcoming the compositional heterogeneity of biomass sources. The article outlines the existing development pattern and highlights critical gaps and future avenues for increasing the storage capacity of traditional, flexible supercapacitors, and it uniquely intergrates green activation, AI optimization, and flexible device engineering.