Synergetic solvent extraction and ionic liquid engineering for one-step carbonization of coal tar pitch toward sodium-ion anodes

IF 6.2 3区材料科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Carbon Letters Pub Date : 2026-06-15 DOI:10.1007/s42823-026-01101-x

Rong Wang, Zhenjie Dai, Ishioma Laurene Egun, Haiyang Yu, Guoliang Ling, Yichao Wang, Zhengfei Chen

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Abstract

Sodium-ion batteries (SIBs) have emerged as a promising complement to lithium-ion batteries due to the natural abundance and low cost of sodium resources. However, the large ionic radius and sluggish kinetics of Na⁺ lead to slow diffusion and inferior electrochemical performance of conventional anode materials. Herein, we report a facile and sustainable strategy for the upcycling of coal tar pitch (CTP) into functional carbon anodes. N-Methyl-2-pyrrolidone (NMP) was first employed for solvent extraction of CTP, followed by incorporation of imidazolium-based ionic liquids, 1-butyl-3-methylimidazolium bromide ([BMIM]Br) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF₆). A single-step carbonization process enabled in situ heteroatom doping and structural regulation of the derived carbons. Systematic structural characterization and electrochemical evaluation reveal that CTP-NMP-[BMIM]Br possesses the highest nitrogen content (4.36 at%), delivers an initial coulombic efficiency of 55.43%, and exhibits excellent cycling stability with a reversible capacity of 153.2 mAh g^− 1 after 500 cycles at 50 mA g^− 1. This better electrochemical performance is attributed to its larger interlayer spacing, better hierarchical pore structure, large pore volume and defect sites that promote better sodium ion storage and transport characteristics. This work presents a green and scalable approach for transforming coal tar pitch into high-value carbon materials and highlights the role of ionic liquids as effective modifiers for tailoring microstructure, heteroatom chemistry, and porosity, thereby enabling high-performance carbon anodes for SIBs.

Graphical abstract

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煤焦油沥青钠离子阳极一步炭化的协同溶剂萃取及离子液体工程

钠离子电池（SIBs）已成为锂离子电池的一个有前途的补充，由于天然丰富的钠资源和低成本。然而，由于Na+离子半径大、动力学慢，导致传统阳极材料扩散缓慢，电化学性能较差。在此，我们报告了一种简单和可持续的策略，将煤焦油沥青（CTP）升级为功能碳阳极。首先采用n -甲基-2-吡咯烷酮（NMP）溶剂萃取CTP，然后加入咪唑基离子液体1-丁基-3-甲基咪唑溴（[BMIM]Br）和1-丁基-3-甲基咪唑六氟磷酸（[BMIM]PF6）。单步碳化工艺实现了原位杂原子掺杂和衍生碳的结构调节。系统的结构表征和电化学评价表明，CTP-NMP-[BMIM]Br具有最高的氮含量（4.36 at%），初始库仑效率为55.43%，在50 mA g−1下循环500次后具有153.2 mAh g−1的可逆容量，具有优异的循环稳定性。更大的层间距、更好的层次化孔隙结构、更大的孔隙体积和缺陷位点促进了钠离子更好的存储和传输特性，从而提高了电化学性能。这项工作提出了一种绿色和可扩展的方法，将煤沥青转化为高价值的碳材料，并强调了离子液体作为调整微观结构、杂原子化学和孔隙度的有效改性剂的作用，从而使sib的高性能碳阳极成为可能。图形抽象

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来源期刊

Carbon Letters CHEMISTRY, MULTIDISCIPLINARY-MATERIALS SCIENCE, MULTIDISCIPLINARY

CiteScore

7.30

自引率

20.00%

发文量

118

期刊介绍： Carbon Letters aims to be a comprehensive journal with complete coverage of carbon materials and carbon-rich molecules. These materials range from, but are not limited to, diamond and graphite through chars, semicokes, mesophase substances, carbon fibers, carbon nanotubes, graphenes, carbon blacks, activated carbons, pyrolytic carbons, glass-like carbons, etc. Papers on the secondary production of new carbon and composite materials from the above mentioned various carbons are within the scope of the journal. Papers on organic substances, including coals, will be considered only if the research has close relation to the resulting carbon materials. Carbon Letters also seeks to keep abreast of new developments in their specialist fields and to unite in finding alternative energy solutions to current issues such as the greenhouse effect and the depletion of the ozone layer. The renewable energy basics, energy storage and conversion, solar energy, wind energy, water energy, nuclear energy, biomass energy, hydrogen production technology, and other clean energy technologies are also within the scope of the journal. Carbon Letters invites original reports of fundamental research in all branches of the theory and practice of carbon science and technology.