Manganese dioxide (MnO) and biomass-derived carbon-based electroactive composite materials for supercapacitor applications

Manganese dioxide (MnO 2 ) is the most promising electrode material for supercapacitors (SCs) due to its low cost, non-toxic nature, high theoretical capacitance, and wide potential window. Meanwhile, biomass-derived carbon has also become a prominent electrode material in recent years due to its cost-effectiveness, eco-friendliness, and availability of biomass in abundance. Carbon can be synthesized from biomass precursors such as plants, animals, and microorganisms via various synthesis and activation techniques. MnO 2 is combined with carbon to obtain composite materials with improved electrochemical properties and structural stability. Sustainable porosity in MnO 2 -biomass-derived carbon composites increases the conductivity and electrochemical performance of the electrode material. Hence, MnO 2 and biomass-derived composite materials have received great attention regarding their potential use as electrode materials in SCs. Recently, significant new developments in the synthesis and testing of such composite materials have been made. In this review, recent reports about such composite materials are listed and analyzed with numerous examples providing the authors with important collective information. Here, we place a strong emphasis on carbons obtained from a variety of biomass and different types of MnO 2 and composites made from them for SC application. The current challenges and prospects in this field of research are also highlighted. This review highlights the importance of MnO 2 & biomass-derived carbon materials and composites made from them for energy storage applications.