关键词: 巴尔沙木, 生物质, 硬碳, 钠离子电池, 电化学性能

Abstract:

Hard carbon prepared from biomass-based precursors offers many advantages as anodes for sodium ion batteries (SIB), such as low cost and sustainability. In this paper, hard carbon was prepared by carbonizing typical fast-growing wood (balsa wood) at various high temperatures and then used as anodes for SIB. The morphology and structural characteristics of the obtained materials were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, specific surface area analysis, and pore size distribution (PSD) measurements. The electrochemical performance of the materials was evaluated by galvanostatic charge-discharge testing, cyclic voltammetry (CV), the galvanostatic intermittent titration technique (GITT), and electrical impedance spectroscopy (EIS). The results showed that the balsa wood-based hard carbon mainly consisted of a fibrous and layered structure, with the interlayer distance decreasing and structural defects increasing as the carbonization temperature increased. Among the samples, the hard carbon prepared at 1100 ℃ exhibited the largest specific surface area (38.8 m²/g) and demonstrated excellent performance in terms of initial Coulombic efficiency, rate capability, and cycling stability. Further studies indicated that the high ionic diffusion rate, low charge transfer resistance, and reduced diffusion-controlled process enabled the materials carbonized at 900 ℃ and 1100 ℃ to perform better at a high current density (5 A/g).

Key words: balsa wood, biomass, hard carbon, sodium ion batteries, electrochemical performance