Heteroatom doping in bio-waste derived activated carbon for enhanced supercapacitor performance: A review

Activated carbon materials derived from bio-waste are known for their unique electronic, chemical, and surface properties, making them attractive for energy storage applications. Despite their potential, these materials often struggle to meet the higher demands for energy and power densities required by advanced energy storage technologies. This challenge has led researchers to explore heteroatom-doped carbon materials, particularly for use as supercapacitor electrodes. This review examines the use of activated carbon derived from bio-waste as an electrode material for supercapacitors and the enhancement of its electrochemical properties through doping with heteroatoms such as boron (B), nitrogen (N), sulphur (S), and phosphorus (P). Doping introduces active sites into the carbon structure, enhances its wettability, and optimizes its pore structure, which together contributes to better electrical conductivity and increased storage capacity. We delve into how converting bio-waste into activated carbon, and incorporating single, dual, and multiheteroatom doping, significantly improves its ability to store energy and conduct electricity. Incorporating multiple atoms (such as B/N, N/S, N/O/P, O/N/S) to carbon networks, known as dual or multi-atom doping, significantly boosts their properties by creating a synergistic effect, enhancing performance more than single atom doping. This exploration focuses on the electrochemical capabilities, specifically assessing their energy storage capacity, durability through charging cycles, and their energy and power output metrics. The article concludes with a call for more research into this area, emphasizing the potential of heteroatom-doped bio-waste derived activated carbon in the future of energy storage technology.