Biomass-Derived Hard Carbon Anodes with Dual Na ⁺ Storage via Structure Engineering toward Capable Sodium-Ion Batteries

Sodium-ion batteries (SIBs) have gained attention on account of the analogical operating principle to lithium-ion batteries (LIBs) and the abundance of sodium resources. It is essential to investigate suitable processing conditions to develop anode materials for SIBs. In this study, hard carbon materials are synthesized from corn stalk, cellulose, and lignin through a series of processes, including precarbonization, alkali-thermal treatment, and carbonization. The treatment conditions and precursors are investigated by evaluating the electrochemical property of various hard carbon materials. The resulting materials S-600-OH-1300, L-600-OH-1300, and C-600-OH-1300 demonstrate high specific capacities of 310.21, 310.19, and 319.92 mAh g–1, respectively, at 0.1 A g–1. S-600-OH-1300 exhibits the most impressive electrochemical property. It delivered a specific capacity of 296.6 mAh g–1 at 1 A g–1 and retained over 215.81 mAh g–1 after 1000 cycles. Additionally, S-600-OH-1300 displays outstanding rate performance, an initial capacity of 198.63 mAh g–1 at 5 A g–1. The superior performance is attributed to the increased interlayer spacing and balanced pore volume, which improve the Na ion storage and transport. Additionally, an “adsorption-intercalation/filling” mechanism of Na ion storage has been proposed in this study.