Preparation of mesoporous hard carbon anode materials by nitrogen doping of biomass to enhance the specific capacity of sodium ion adsorption

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Vol. 991; p. 119190
• Main Authors: Meng, Wei, Gao, Yinyi, Zhu, Kai, Cao, Dianxue
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.08.2025
• Subjects: Biomass-derived carbon; Hard carbon anode materials; Mesoporous; Nitrogen doping; Sodium ion batteries; Sodium ion batteries; Nitrogen doping; Hard carbon anode materials; Mesoporous; Biomass-derived carbon
• ISSN: 1572-6657
• DOI: 10.1016/j.jelechem.2025.119190

This study synthesized a hard carbon anode material (HC-N1300) with hierarchical micro/mesoporous structure through biomass-derived nitrogen doping, aiming to explore its application in sodium-ion batteries (SIB). Structural characterization reveals that HC-N1300 possesses well-developed micro/mesopores, which significantly shorten the diffusion pathways for sodium ions (Na+). Compositional analysis further demonstrates an increased ratio of pyridinic-N to pyrrolic-N configurations, providing abundant electrochemically active sites. These synergistic structural and compositional advantages collectively enhance the adsorption capability in the slope region. In half-cell evaluations, the HC-N1300 delivered an initial discharge capacity of 486 mAh g−1 at 0.1 A g−1 with a reversible capacity of 330 mAh g−1. Remarkably, it maintained 88.5 % capacity retention after 1000 cycles at 0.5 A g−1. Mechanistic analysis revealed that nitrogen doping plays a crucial role in pore formation during carbonization. The hierarchical porous architecture not only increases active sites but also facilitates rapid Na+ diffusion, thereby effectively improving both plateau capacity and rate capability. This work provides valuable insights for designing high-performance anode materials for SIB. •Precision microstructure engineering via biomass-derived nitrogen doping. A hierarchical micro-mesoporous network (pore size distribution: 2–110 nm) and a nitrogen conformational shift (elevated ratio of pyridine-N and pyrrolidine-N) was constructed through nitrogen doping, enabling ultra-short Na+ diffusion pathways and exceptionally high active site density.•Breakthrough electrochemical performance. 486 mAh g−1 initial discharge capacity at 0.1 A g−1 with 330 mAh g−1 reversible capacity. 88.5 % capacity retention after 1000 cycles at 0.5 A g−1 (ultralow decay rate of 0.0115 % per cycle). Superior rate capability: maintains 236 mAh g−1 at 2 A g−1 (71 % retention of 0.1 A g−1 capacity)•First-established dual-function mechanism of nitrogen doping. Pore engineering: nitrogen-induced N2 release creates 3D interconnected ion transport channels during carbonization. Interlayer spacing optimization: expanded graphitic interlayer spacing to 0.41 nm (22.4 % larger than graphite), significantly reducing Na+ intercalation energy barriers by 34 %.