Lotus root starch derived sustainable hard carbon for fast-charging sodium-ion batteries

The exploration of biomass-based hard carbon as an anode for sodium-ion batteries (SIBs) has been widely pursued, driven by its low production costs and the abundant supply of raw materials. However, developing sustainable hard carbon with superior fast-charging capabilities remains a critical challenge, hindering its widespread application. Herein, a unique hard carbon was synthesized from lotus root starch through a green, acid/alkali-free pyrolysis process. Moreover, the optimized S1400 anode demonstrates remarkable fast-charging performance, resulting from the large layer spacing and robust solid electrolyte interface (SEI) film. Specifically, the S1400 anode delivers a high capacity of 274.8 mAh g- 1 after 2000 cycles at 1.5 A g- 1 (5C, 81.0% retention). Meanwhile, the S1400//NVP full cell exhibits an outstanding rate performance, achieving 292.9 mAh g- 1 at 0.5 A g- 1. The findings emphasize the potential of environmentally friendly hard carbon derived from lotus root starch, offering a viable pathway for the commercialization of advanced hard carbon anodes.