Advantageous Tubular Structure of Biomass-Derived Carbon for High-Performance Sodium Storage

Biomass-derived carbon (BDC) is viewed as one of the most promising anode candidates for sodium-ion batteries (SIBs) owing to its natural abundance, low cost, and sustainability. However, fabrication of BDC with a preferred microstructure and morphology for high-performance sodium storage still remains a dilemma. Herein, we report using natural parasol fluff as a biomass precursor to highlight the significant role of the tubular structure for achieving high electrochemical performances with BDC. Different from high-temperature pyrolysis (over 1000 °C) commonly used for BDC, the interconnected porous carbon framework with a well-maintained tubular structure was prepared in a mild calcination temperature of 500 °C with the aid of KOH activation and Co2+-assisted graphitization. The as-prepared material with a large interlayer spacing (0.405 nm) and abundant self-doping heteroatoms demonstrates its excellent performance as the anode of SIBs by delivering a reversible capacity of 359.0 mA h g–1 at 30 mA g–1. Impressively, its full-cell capacity reaches 257.2 mA h g–1 at 30 mA g–1, which is among the highest values for carbon-based full-cell assembly. In addition to offering a potential industrializable BDC choice, this work highlights the significance of the tubular structure and provides tactics for screening of biomass precursors as well as the design of high-performance carbonaceous materials.