Biomass-derived highly graphitized hard carbon materials via tandem carbonization–graphitization for high-performance sodium-ion batteries

Abstract

Biomass-derived hard carbon is considered as a promising anode material for sodium-ion batteries (SIBs) owing to the tunable microstructure and cost-effectiveness. Herein, an innovative and controllable strategy of combining carbonization with graphitization was proposed to synthesize biomass-derived highly graphitized hard carbon, which was proven to effectively tailor the structural and surface properties of anodes for SIBs. Cellulose-based hard carbon (CBHC) delivered an outstanding reversible capacity of 320.38 mAh g⁻¹ at 20 mA g⁻¹, a superior rate capability of 188.47 mAh g⁻¹ at 2000 mA g⁻¹, and exceptional cycling stability with 88.15% capacity retention after 1000 cycles at 2000 mA g⁻¹, attributed to the synergistic effects of its tailored pore structure, optimal defect concentration, suitable interlayer spacing, and the formation of a NaF-rich solid electrode interphase (SEI) layer on the anode surface. Simply put, this work proposed a promising strategy for synthesizing biomass-derived highly graphitized hard carbon materials tailored for high-performance SIBs.