Typha-derived hard carbon for high-performance sodium ion storage

We report a low-cost typha-derived hard carbon material, which is prepared by a facile process with the combination of the phosphoric acid activation and the carbonization at a low temperature of 500 °C, as anode for sodium ion batteries. Benefiting from the nanoporous structure and abundant functional groups, the as-prepared typha-derived carbon material with the acid activation delivers a high reversible capacity of 204.8 mAh g⁻¹ at a current density of 100 mA g⁻¹ after 400 cycles, which is much higher than 125.9 mAh g⁻¹ of the typha-derived carbon material without the acid activation. This work offers a new biomass-derived carbon material for sodium ion storage.