物理化学学报 >> 2025, Vol. 41 >> Issue (3): 100028.doi: 10.3866/PKU.WHXB202406009

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前驱体机械压实制备高密度活性炭及其致密电容储能性能

李齐齐1,†, 张苏1,*,†(), 江娱婷2, 朱琳娜3, 郭楠楠3, 张晶1, 李禹彤1, 魏彤1,4, 范壮军1,4,*()   

  1. 1 中国石油大学(华东)材料科学与工程学院, 山东 青岛 266580
    2 辽宁师范大学化学化工学院, 辽宁 大连 116029
    3 新疆大学化学学院, 碳基能源资源化学与利用国家重点实验室, 乌鲁木齐 830017
    4 合肥综合性国家科学中心能源研究院, 合肥 230031
  • 收稿日期:2024-06-11 修回日期:2024-07-29 录用日期:2024-07-30 发布日期:2024-12-14
  • 通讯作者: Email: suzhangs@163.com (张苏)fanzhj666@163.com (范壮军)
  • 作者简介:

    †These authors contributed equally to this work.

  • 基金资助:
    国家自然科学基金项目(52062046); 国家自然科学基金项目(52302336); 山东省泰山学者计划(tsqn202306131); 山东省泰山学者计划(tsqn202312123); 山东省自然科学基金重大基础研究项目(ZR2019ZD51)

Preparation of High Density Activated Carbon by Mechanical Compression of Precursors for Compact Capacitive Energy Storage

Qiqi Li1, Su Zhang1,*(), Yuting Jiang2, Linna Zhu3, Nannan Guo3, Jing Zhang1, Yutong Li1, Tong Wei1,4, Zhuangjun Fan1,4,*()   

  1. 1 School of Material Science and Engineering, China University of Petroleum (East China), Qingdao 266580, Shandong Province, China
    2 School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, Liaoning Province, China
    3 State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, China
    4 Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
  • Received:2024-06-11 Revised:2024-07-29 Accepted:2024-07-30 Published:2024-12-14
  • Contact: Email: suzhangs@163.com (Su Zhang)fanzhj666@163.com (Zhuangjun Fan)
  • Supported by:
    the National Natural Science Foundation of China(52062046); the National Natural Science Foundation of China(52302336); the Taishan Scholar Project of Shandong Province(tsqn202306131); the Taishan Scholar Project of Shandong Province(tsqn202312123); the Key Basic Research Projects of Natural Science Foundation of Shandong Province(ZR2019ZD51)

摘要:

大比表面积活性炭的密度普遍较低、体积储能性能不佳,难以满足超级电容器的小型化发展需求。针对此,本工作提出在活化前对炭前驱体进行机械压实以提高活性炭密度的普适性方法,并研究了机械压实对由外而内活化(炭粉/KOH混合物)和均匀离子活化(热解含钾盐类)所制备活性炭的比表面积、孔结构和电容储能性能的影响规律。结果表明,对前驱体进行机械压实能够提高活化反应效率、活性炭密度和体积电容储能性能。随着机械压力升高,由外而内活化所得活性炭的比表面积和孔隙率先升高后降低,原因在于机械压实能够消除颗粒间的空隙以增加前驱体与活化剂之间的接触,进而显著提高了活化效率。对于均匀离子活化,活性炭的比表面积和孔隙率呈现先降低后升高的趋势,这可能是由于致密前驱体抑制了热解过程中产生的活性气体分子(H2O、CO2等)快速散逸,使之继续参与活化反应,提高了活化刻蚀效率。本工作为大比表面积和高密度活性炭的设计制备提供了简单思路。

关键词: 活性炭, 机械压实, 活化, 超级电容器, 体积比容量

Abstract:

Activated carbons are widely used as the electrode material for supercapacitors owing to their large surface area, moderate conductivity, and outstanding electrochemical stability. However, large-surface-area activated carbons usually show low density and poor volumetric energy storage performance, which is difficult to meet the development of devices miniaturization. Mechanical compression is a simple and effective method to improve the density of the activated carbons. However, most of the studies focus on mechanical compression of the as-prepared porous carbon materials. Preparation of high-density activated carbons by mechanical compression of the carbon precursors has been proposed. But the surface area and porous structure evolution, and the possible mechanism have rarely investigated. Herein, we propose a universal method to improve the density of the activated carbons by mechanical compression of the precursors before activation. The influence of mechanical compression on the surface area, porous structure, and capacitive energy storage performance of the activated carbons prepared by two typical methods, outside-in activation (carbon powder/KOH mixture) and homogeneous ion activation (pyrolysis of potassium-containing salts), are studied. Mechanical compression of the precursors can generally improve the activation reaction efficiency, as well as the density and volumetric capacitive performance of the activated carbons. However, the surface area and porous structure evolution mainly depend on the carbon precursor and pore-forming process. For outside-in activation, the surface area and porosity of the activated carbons show a first increasing and then decreasing trend with the increase of mechanical pressure. This is because mechanical compression enhances the contact between the carbon precursors and activator through eliminating the voids between particles, significantly improves the activation efficiency. For homogeneous ion activation, the surface area and porosity of activated carbons show a trend of decreasing first and then increasing. The reason is deduced as compressed precursors inhibit the rapid release of active gas molecules (H2O, CO2 etc.) produced during pyrolysis. These gas molecules further participate in the activation etching reaction and promote the activation efficiency. The optimized sample shows high gravimetric and volumetric capacitances of 316 F·g-1/291 F·cm-3 and 131 F·g-1/92 F·cm-3 at 1 A·g-1 in aqueous and organic electrolytes, respectively. This work provides a simple way for design and preparation of activated carbons with large surface area and high density.

Key words: Activated carbon, Mechanical compression, Activation, Supercapacitor, Volumetric capacitance