Sawdust-derived hard carbon as a high-performance anode for sodium-ion batteries

Hard carbon, which consists of randomly stacked graphitic layers with a considerable amount of pores structure, is a potential anode material for sodium-ion batteries. Low-cost sawdust-derived hard carbon has been prepared by pyrolyzing at different carbonization temperatures. Sawdust pyrolyzed at 1400 °C (SC-1400) reveals the optimized electrochemical performance, which displays the highest initial reversible capacity of 309.2 mAh g−1 at 0.1 C (30 mA g−1) with initial coulomb efficiency of 83.4%, and remains the capacity retention ratio of 95.8% after 100 cycles. The excellent electrochemical performances of SC-1400 are attributed to the small specific surface area, reasonable microporous structure, and large interlayer spacing.