Development of Hard carbon Anodes from Biomass precursors for Sodium-ion battery application

Hard carbon is widely recognised as a promising anode material for sodium-ion batteries due to its favourable characteristics, including larger interlayer spacing (>0.35 nm), localized and tunable crystallinity, controlled specific surface area and porosity, and low-cost, scalable processing routes. Hard carbon with high plateau capacity has been developed from low-cost biomass precursors such as coconut spathe fiber and wood. Coconut spathe fiber-derived hard carbon exhibits a specific capacity of 280 mAh/g at 20 mA/g current density, whereas wood-derived hard carbon shows 237 mAh/g at the same current density. Both materials show an impressive plateau capacity contribution exceeding 62 %, highlighting their effective Na⁺ storage via intercalation mechanisms. Their combination of high plateau capacity, low-cost production, and excellent cycling stability underscores their strong potential for practical sodium-ion battery applications. These results also provide a promising materials-design strategy for engineering next-generation, sustainable hard carbon anodes with enhanced energy storage characteristics.