Green method for the synthesis of biobased carbon from miscanthus × giganteus for lithium-ion batteries

Graphite, widely used in lithium-ion batteries (LIBs) due to its cycle stability and high conductivity, is limited by a capacity of 372 mA h g‒1 and its high reactivity with electrolyte components. As an alternative, nanostructured carbon materials like mesoporous carbon offer higher capacities due to their porous structures, which facilitate rapid ion transport and diffusion. This study introduces a sustainable and scalable synthesis method for bio-based mesoporous carbon derived from miscanthus × giganteus (MG), a fast-growing energy crop. Using cascaded hydrothermal carbonization followed by calcination, we produced mesoporous carbon with specific surface areas exceeding 450 m2 g‒1, substantially higher than the 20–80 m2 g‒1 of the original hydrochar. This approach avoids the chemical waste and high costs associated with traditional pyrolysis and chemical activation methods. The resulting material achieved discharge capacities of 700 mA h g‒1 at 0.5 °C, outperforming commercial graphite and other chemically activated carbons from similar biomass sources with even higher specific surface area.