储能科学与技术 ›› 2025, Vol. 14 ›› Issue (6): 2248-2255.doi: 10.19799/j.cnki.2095-4239.2024.1234

• 储能材料与器件 • 上一篇    下一篇

低成本干法石墨厚电极的制备与性能研究

阮晶晶1,3(), 巫湘坤2, 李勇慧1, 赵冲冲3, 李珅珅1, 王童飞3, 梁圣杰3, 高桂红1,3()   

  1. 1.龙子湖新能源实验室，氢能储能中心，河南 郑州 450003
    2.中国科学院过程工程研究所，离子液体清洁过程北京重点实验室，北京 100190
    3.郑州中科新兴产业技术研究院，河南省储能材料与过程重点实验室，河南 郑州 450003
  • 收稿日期:2024-12-26 修回日期:2025-01-11 出版日期:2025-06-28 发布日期:2025-06-27
  • 通讯作者: 高桂红 E-mail:15702413613@163.com;ghgao@ipezz.ac.cn
  • 作者简介:阮晶晶（1989—），女，硕士，工程师，研究方向为电池材料及锂系电池，E-mail：15702413613@163.com；
  • 基金资助:
    河南省科技攻关(242102241044);河南省重点研发计划(221111240100);河南省重点研发专项(241111241500)

Preparation and performance studies of low-cost graphite thick dry electrodes

Jingjing RUAN1,3(), Xiangkun WU2, Yonghui LI1, Chongchong ZHAO3, Shenshen LI1, Tongfei WANG3, Shengjie LIANG3, Guihong GAO1,3()   

  1. 1.Longzihu New Energy Laboratory, Hydrogen Energy Storage Center, Zhengzhou 450003, Henan, China
    2.Beijing Key Laboratory of Ionic Liquids Clean Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
    3.Zhengzhou Institute of Emerging Industrial Technology, Henan Key Laboratory of Energy Storage Materials and Processes, Zhengzhou 450003, Henan, China
  • Received:2024-12-26 Revised:2025-01-11 Online:2025-06-28 Published:2025-06-27
  • Contact: Guihong GAO E-mail:15702413613@163.com;ghgao@ipezz.ac.cn

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摘要：

采用黏结剂纤维化法制备了锂离子电池石墨干法电极，探讨电极厚度、黏结剂聚四氟乙烯(PTFE)含量和碳纳米管(CNT)对干法电极的影响，选用扫描电子显微镜(SEM)和X射线能谱仪(EDS)对干法电极片的形貌和元素分布进行了分析测试，借助电子万能试验机、四探针内阻仪和光学接触角测量仪，对石墨干法电极片进行拉伸强度、电子导电性和电解液的浸润性测试，通过充放电测试手段研究了干法电极片的电化学性能。结果表明，当电极厚度超过300 μm时，电化学性能明显变差，所制备极片的厚度应控制在300 μm以内。综合电化学性能、拉伸性能、导电性和对电解液的浸润性，当石墨∶PTFE∶CNT∶导电炭黑(SP)质量比为96∶1∶1∶2时，能达到首效为91.7%，可逆容量大于330 mAh/g，面容量为11.28 mAh/cm2，拉伸率为9.06%，电阻为24.1 Ω，与电解液接触角为65.33°。通过SEM可以清楚地看到在电极的表面和横截面均有丰富的PTFE，PTFE以纤维状态存在，形成具有层次结构的分支状纤维，在电极内部构建出一个连续的网状架构。在制备石墨干法电极片的过程中发现引入碳纳米管后，更易制备成极片，而且极片的韧性和导电性得到很大的提升。面对高能量密度的需求，厚电极的制造也是关键的发展方向，与湿法涂布工艺相比，在没有溶剂情况下的干法电极制造可以突破厚电极制造的限制，干法电极技术可以提供一种更低成本、对环境无害且可持续发展的高效电极制备方案。

关键词: 锂离子电池, 干法电极, PTFE纤维化, 石墨, 厚电极

Abstract:

A graphite dry electrode for lithium-ion batteries was fabricated using a binder fiberization technique. The effects of electrode thickness, polytetrafluoroethylene (PTFE) content, and carbon nanotube (CNT) addition on electrode performance were systematically investigated. Morphological and elemental distribution analyses were conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Mechanical, electrical, and wetting properties were evaluated using a universal testing machine, a four-probe internal resistance meter, and an optical contact angle goniometer, respectively. Electrochemical performance was assessed through charge-discharge testing. The results showed that when the electrode thickness exceeded 300 μm, electrochemical performance deteriorated markedly; therefore, the thickness should be limited to ≤300 μm. Based on comprehensive evaluation, including electrochemical behavior, tensile strength, conductivity, and electrolyte wettability, the optimal formulation was identified as graphite∶PTFE∶CNT∶Super P (SP) at a mass ratio of 96∶1∶1∶2. This composition yielded a coulombic efficiency of 91.7%, a reversible capacity exceeding 330 mAh/g, a surface capacity of 11.28 mAh/cm2, a tensile elongation of 9.06%, a resistance of 24.1 Ω, and a contact angle of 65.33°. SEM images confirmed the presence of abundant PTFE fibers on the surface and cross-section of the electrode, forming a branched and hierarchically structured network throughout the electrode matrix. The inclusion of CNTs enhanced both the resilience and conductivity of the electrode sheet, facilitating easier fabrication. To meet the growing demand for high energy density, thick electrode manufacturing has become a critical focus. Unlike conventional wet-coating techniques, dry electrode fabrication eliminates the need for solvents, offering a cost-effective, environmentally friendly, and scalable approach to producing thick electrodes.

Key words: lithium-ion batteries, dry electrode, PTFE fiberization, graphite, thick electrode

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