Engineering coal-based carbon microstructures for energy storage

Carbon (C)-based materials are gaining significant attention as potential alternatives to alkali metal anodes, such as lithium (Li), sodium (Na), and potassium (K). Their advantages lie in relatively lower redox potentials, improved safety, and cost-effectiveness, rendering them suitable for large-scale use in metal-ion batteries (MIBs) and supercapacitors (SCs). Among the available C sources, coal and its derivatives stand out due to their abundance, high C content, and favorable structural features. Despite the moderate electrochemical performance of current coal-derived C (CDC) materials, developing high-performance, low-cost CDC remains essential for reducing the overall cost of energy storage systems. This review focuses on microstructural modification strategies, including heteroatom doping, defect tailoring, and pore architecture optimization, while critically examining their limitations. It also outlines existing challenges and proposes potential research directions toward the advancement of efficient CDC materials.