Prykhodska Sofiia, Schutjajew Konstantin, Kalder Laura, Hermesdorf Marius, Troschke Erik, Leistenschneider Desirée, Langenhorst Falko, Härk Eneli, Oschatz Martin
Friedrich-Schiller-University Jena, Institute for Technical Chemistry and Environmental Chemistry, Philosophenweg 7a, 07743, Jena, Germany.
Helmholtz Institute for Polymers in Energy Applications Jena (HIPOLE Jena), Lessingstrasse 12-14, 07743, Jena, Germany.
Nanoscale. 2025 Aug 15;17(32):18678-18689. doi: 10.1039/d5nr01053e.
Non-graphitizing (so-called "hard") carbons, derived from natural and abundant precursors such as biomass, sugars (, glucose and sucrose) and polysaccharides (, starch and cellulose), are widely investigated as negative electrode materials for alkali metal-ion storage in secondary batteries because of their suitable structural features, including the unique "closed porosity". The formation of such microstructures depends on the heating conditions, such as the temperature or holding time of either carbohydrate condensation during preliminary carbonization ("pre-carbonization") or final carbonization. Numerous studies have extensively examined the impact of condensation and carbonization temperatures on the microstructure of hard carbons and their resulting electrochemical properties. Comparatively less research attention has been devoted to the influence of the heating rate in the low-temperature region, where it can be expected that the structure of the final hard carbon is largely established and a significant impact can be expected. Hence, this work is dedicated to investigating the effect of the rate of preheating, from room temperature to 600 °C, of glucose-derived carbon on its structure and electrochemical properties after final high-temperature carbonization at 1500 °C. Hard carbons obtained using 2, 10 and 200 K min pre-carbonization temperature ramps exhibit distinct differences in plateau capacity values for sodium (226 ± 15.60 mAh g, 206 ± 13.27 mAh g, and 192 ± 9.44 mAh g, respectively). This points to differences in closed porosity, defectiveness, and pore symmetry. The material preheated at the slowest ramp has the highest internal surface area, defectiveness, and highly asymmetrical pores, thereby promoting an increase in specific sodiation capacity (326 ± 21 mAh g), particularly pronounced in the plateau region (226 ± 15.60 mAh g). These findings imply the potential to regulate the microstructure of hard carbons through the initial heating rate during carbonization.
非石墨化（所谓的“硬”）碳源自生物质、糖类（如葡萄糖和蔗糖）以及多糖类（如淀粉和纤维素）等天然且丰富的前驱体，因其具有适宜的结构特征，包括独特的“封闭孔隙率”，而被广泛研究作为二次电池中碱金属离子存储的负极材料。此类微观结构的形成取决于加热条件，例如在初步碳化（“预碳化”）或最终碳化过程中碳水化合物缩合的温度或保温时间。众多研究广泛考察了缩合温度和碳化温度对硬碳微观结构及其电化学性能的影响。相对而言，较少的研究关注低温区域加热速率的影响，在该区域预计最终硬碳的结构基本形成且可能产生显著影响。因此，本工作致力于研究从室温到600℃的预热速率对葡萄糖衍生碳在1500℃最终高温碳化后的结构和电化学性能的影响。使用2、10和200K min的预碳化温度升温速率获得的硬碳在钠的平台容量值上表现出明显差异（分别为226±15.60 mAh g、206±13.27 mAh g和192±9.44 mAh g）。这表明在封闭孔隙率、缺陷度和孔对称性方面存在差异。以最慢升温速率预热的材料具有最高的内表面积、缺陷度和高度不对称的孔，从而促进了比钠化容量的增加（326±21 mAh g），在平台区域尤为明显（226±15.60 mAh g）。这些发现意味着在碳化过程中通过初始加热速率调节硬碳微观结构的潜力。
