木质素衍生多层碳纳米纤维，用于高性能超级电容器

摘要：木质素作为一种丰富且可再生的资源，其价值化利用对推动可持续材料创新至关重要。本文，中国科学院长春应用化学研究所董绍俊院士、Kai Rong等研究人员在《ACS Appl. Mater. Interfaces》期刊发表名为“Lignin-Derived Hie

1成果简介

木质素作为一种丰富且可再生的资源，其价值化利用对推动可持续材料创新至关重要。本文，中国科学院长春应用化学研究所董绍俊院士、Kai Rong等研究人员在《ACS Appl. Mater. Interfaces》期刊发表名为“Lignin-Derived Hierarchically Porous Carbon Nanofibers via Deep Eutectic Solvent Electrospinning and Silica-Templated Etching for High-Performance Supercapacitors”的论文，研究提出了一种绿色且成本效益高的策略，用于合成木质素衍生分级多孔碳纳米纤维（HPCFs）。该方法采用氯化胆碱-乳酸深共晶溶剂（ChCl-LA DES）对木质素进行溶解，随后通过湿法电纺制备木质素基纤维气凝胶。二氧化硅纳米球作为牺牲模板均匀嵌入电纺纤维中以形成宏观孔，而木质素碳化过程则产生了丰富的介孔和微孔，最终制备出具有多尺度孔结构的碳纳米纤维。

此外，通过调节二氧化硅纳米球含量可调控分级孔分布，进而优化碳纳米纤维的纹理特性和电化学性能。优化后的碳纳米纤维（100-HPCF）掺入100 mg SiO₂纳米球，其比表面积（779.515 m²/g）和比电容（237.1 F/g at 0.5 A/g）显著提升，较未采用模板的木质素衍生电纺碳纤维（LESCFs）。此外，100-HPCF展现出卓越的循环稳定性，在15000次循环后仍保持97.7%的峰值电容。通过整合木质素增值利用、DES辅助加工及分级孔结构优化，本研究为开发具有卓越超级电容器性能的先进碳材料开辟了一条可持续且可行的路径。

2图文导读

图1. Schematic diagram of electrospinning device construction and postprocessing procedures for preparing LESCF or x-HPCF.

图2. (a) Photograph, (b1, b2) SEM images, and (c) TEM images of LESCF; (d) photograph, (e1, e2) SEM images, and (f) TEM image of 100-SiO2-LESA; (g) photograph, (h1, h2) SEM images, and (i) TEM image 100-HPCF. (Panels 1 and 2 of the pairs of panels b, e, and h are SEM images at different magnifications.) SAED patterns (j) of LESCF and (k) of 100-HPCF. (l) EDS color mapping area and C, O, and Si elemental mapping images (l1–l3) of 100-SiO2-LESA; (m) EDS color mapping area and C, O, and Si elemental mapping images (m1–m3) of 100-HPCF.

图3. (a) XRD patterns, (b) Raman patterns, (c) N2 adsorption–desorption isotherms, (d) BJH pore diameter distributions, and (e) HK method micropore diameter distributions of LESCF and x-HPCF.

图4. (a) CV curves of different supercapacitor electrodes in 6.0 M KOH aqueous solution at a scan rate of 100 mV/s, (b) CV curves of the 100-HPCF supercapacitor electrodes at scan rates of 10–200 mV/s, (c) current density of the different supercapacitor electrodes plotted against the scan rate, (d) GCD curves of different supercapacitor electrodes at a current density of 1 A/g, (e) GCD curves of the 100-HPCF supercapacitor electrodes at current densities of 0.5–10 A/g, and (f) specific capacitance of different supercapacitor electrodes at different current densities.

图5. (a) Relationship between logarithm peak currents and logarithm scan rates of 100-HPCF, (b) b values comparison of LESCF and x-HPCFs, (c) diffusion- and capacitive-controlled contributions to charge storage of 100-HPCF electrode at 100 mV/s, and (d) charge storage contribution calculations of 100-HPCF at different scan rates.

图6. (a) Nyquist plots of different supercapacitor electrodes in 6.0 M KOH aqueous solution (inset: magnification of the Nyquist plots), (b) frequency response of different supercapacitor electrodes, and (c) variation in the specific capacitance for 15000 cycles of 100-HPCF supercapacitor electrodes at a current density of 10 A/g.

图7. (a) CV curves of the 100-HPCF symmetric supercapacitor at scan rates of 10–200 mV/s, (b) GCD curves of the 100-HPCF symmetric supercapacitor at current densities of 0.5–10 A/g, (c) CV curves of the LESCF and 100-HPCF symmetric supercapacitors at scan rates of 100 mV/s, (d) specific capacitance of the LESCF and 100-HPCF symmetric supercapacitors at different current densities, (e) Ragone plots of LESCF- and 100-HPCF-based symmetric supercapacitors and related comparisons to recent studies, and (f) photographs showing that two series connection 100-HPCF symmetric supercapacitors can light up LEDs with different colors.

3小结

本研究成功证明了利用氯化物-丙烯酸酯双组分溶剂（ChCl-LA DES）与牺牲性二氧化硅模板技术相结合，制备木质素基高强度碳纤维（HPCFs）的可持续且可行策略。通过采用DES作为溶解木质素的绿色溶剂，结合湿法电纺丝制备纤维，并引入SiO₂纳米球后进行蚀刻处理，我们成功获得了碳纤维中的三模孔结构。此外，通过调整掺杂SiO₂纳米球的含量，可调控孔隙的层次结构。得益于包含大孔、中孔和微孔的多尺度孔结构构建，HPCF展现出改善的织构特性和增强的比表面积。为了评估电化学性能，采用LESCF和HPCF制备了超级电容器电极和对称超级电容器电池。

HPCF展现出与发展出的分级孔结构一致的优异比电容和能量密度。二氧化硅纳米球掺杂含量对HPCFs的性能和电化学性能也产生了显著影响。优化后的100-HPCF展现出最高的比电容（237.1 F/g，电流密度为0.5 A/g）和能量密度（31.56 Wh/kg，功率密度为250 W/kg），并通过持续的LED照明证明了其实用性。100-HPCF还展现出卓越的电容保持能力，在15000次循环后仍保留97.7%的峰值比电容，表明其具有出色的电化学稳定性。本研究不仅实现了木质素在高性能储能材料中的增值利用，还为设计具有定制孔隙层级结构的生物质衍生碳纤维材料建立了可行策略。此外，本研究还为通过DES辅助湿法电纺制备各种掺杂纤维材料提供了可行尝试和思路扩展。

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