Synergistic regulation of bagasse-based hard carbon and its sodium storage properties by delignification and temperature

Le résumé fourni par la source

Abstract Bio-based hard carbon is regarded as a highly promising anode material for sodium-ion batteries, thanks to its abundant raw materials, low cost, and suitable interlayer spacing. However, the carbon skeleton originating from biological matrices contains numerous inherent micropores and disordered channels, which directly lead to a low initial Coulombic efficiency (ICE) and cause capacity decay. In this study, bagasse was used as a precursor, and its microstructure was regulated through delignification pretreatment and different annealing temperatures. Three groups of contrast samples were prepared: direct annealing of bagasse at 1400 °C, annealing at 1400 °C after delignification, and annealing at 1300 °C after delignification. The effects of delignification pretreatment and annealing temperature on the morphology, graphitization degree, and defect configuration of the carbon materials were systematically examined, and their sodium storage performance was evaluated. Electrochemical tests indicate that the hard carbon obtained after delignification followed by annealing at 1400 °C exhibits superior reversible capacity, cycling stability, and rate performance. This is mainly attributed to the fact that appropriate delignification pretreatment optimizes the microstructure of hard carbon, facilitating the formation of short-range graphitic layers and closed pores, thereby enabling effective sodium ion storage. Meanwhile, a suitable annealing temperature promotes the ordering degree of the carbon skeleton and the ordered rearrangement of carbon layers. This study proffers a simple and effective strategy for preparing low-cost biomass-derived carbon anodes through straightforward pretreatment and temperature regulation, offering a feasible approach for the application of bagasse in sodium-ion batteries.

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