储能科学与技术 ›› 2025, Vol. 14 ›› Issue (1): 1-12.doi: 10.19799/j.cnki.2095-4239.2024.0712

• 储能材料与器件 •    下一篇

原位聚合制备PDOL基固态电解质及其在锂金属电池中的应用

江训昌1,2(), 喻科霖3, 杨大祥1,2,4(), 廖敏会5, 周洋5   

  1. 1.重庆交通大学绿色航空技术研究院
    2.重庆交通大学
    3.重庆市育才中学
    4.绿色航空能源动力重庆市重点实验室,重庆 400000
    5.重庆长安新能源汽车有限公司,重庆 400074
  • 收稿日期:2024-07-29 修回日期:2024-08-08 出版日期:2025-01-28 发布日期:2025-02-25
  • 通讯作者: 杨大祥 E-mail:2641996850@qq.com;6669203@qq.com
  • 作者简介:江训昌(1998—),男,硕士研究生,从事固态电解质研究,E-mail:2641996850@qq.com
  • 基金资助:
    重庆市自然科学基金面上项目(CSTB2022NSCQ-MSX0479)

Preparation of PDOL-based solid electrolyte by in-situ polymerization and its application in lithium metal batteries

Xunchang JIANG1,2(), Kelin YU3, Daxiang YANG1,2,4(), Minhui LIAO5, Yang ZHOU5   

  1. 1.The Green Aeromechanics Research Institute of Chongqing Jiaotong University
    2.Chongqing Jiaotong University
    3.Chongqing Yucai Middle School
    4.Chongqing Key Laboratory of Green Aviation Energy and Power, Chongqing 400000, China
    5.Chongqing Chang'an New Energy Automobile corporation, Chongqing 400074, China
  • Received:2024-07-29 Revised:2024-08-08 Online:2025-01-28 Published:2025-02-25
  • Contact: Daxiang YANG E-mail:2641996850@qq.com;6669203@qq.com

摘要:

通过同轴静电纺丝工艺,制备出在聚偏氟乙烯(PVDF)纳米纤维表面包覆了氧化钇稳定氧化锆(YSZ)纳米颗粒的YPVDF纳米纤维膜,并以1,3-二氧戊环(DOL)为聚合物前驱体单体,三(三氟磺酸)铝[Al(OfT)3]为引发剂,双三氟甲基磺酰亚胺锂(LiTFSI)为锂盐,氟代碳酸乙烯酯(FEC)为SEI膜添加剂,采用原位聚合工艺,在高比表面积的YPVDF纳米纤维基膜中原位聚合生成PDOL基复合固态电解质,PDOL与YPVDF纤维表面的YSZ形成大量的YSZ/PDOL有机-无机离子快速传输界面,制备出的PDOL@YPVDF-CSE在室温下拥有0.94×10-4 S/cm的离子电导率;YPVDF纤维上YSZ的Lewis酸位点(Zr4+、Y3+、氧空位)能够吸附LiTFSI中的阴离子,促进LiTFSI解离出Li+,从而使得PDOL@YPVDF-CSE具有0.78的锂离子迁移数,同时YSZ提供的Lewis酸位点可以协同Al(OfT)3促进DOL开环聚合,使DOL单体的转化率达到98.2%。此外,YPVDF纳米纤维的引入使得PDOL@YPVDF-CSE的耐热分解温度提升至312 ℃。以PDOL@YPVDF-CSE组装的Li|PDOL@YPVDF-CSE|Li锂对称电池,能够稳定循环1500 h以上;组装的LFP|PDOL@YPVDF-CSE|Li电池在0.5C倍率下循环800次以后,容量保持率为97.4%,在2 C倍率下循环500次后,容量保持率为96.8%。同时,以LiNi0.6Co0.2Mn0.2O2(NCM622)为正极组装的NCM622|PDOL @YPVDF-CSE|Li电池在1 C倍率下循环150次后,容量保持率为96.2%。

关键词: 同轴静电纺丝, 聚(1,3-二氧戊环), 原位聚合, 电化学性能, 复合固态电解质

Abstract:

YPVDF nanofiber membranes coated with yttria-stabilized zirconia (YSZ) nanoparticles on the surface of polyvinylidene fluoride (PVDF) nanofibers were prepared by a coaxial electrospinning process. In this process, 1,3-dioxolane (DOL) was used as the polymer precursor monomer; tris (trifluoromethanesulfonic acid) aluminum (Al(OfT)3) was used as the initiator; LiTFSI was used as the lithium salt; and FEC was used as the SEI film additive. In situ polymerization was performed on the YPVDF nanofiber base film with a high surface area to generate PDOL. PDOL formed a large number of YSZ/PDOL organic-inorganic rapid-ion-transport interfaces with YSZ on the surface of YPVDF fibers. PDOL@YPVDF-CSE has an ionic conductivity of 0.94 × 10-4 S/cm at room temperature. The Lewis acid sites (Zr4+, Y3+, and oxygen vacancies) of the YSZ on the YPVDF fibers facilitate the adsorption of anions from LiTFSI, thus promoting the dissociation of Li+ from LiTFSI. Therefore, PDOL@YPVDF-CSE YSZ has a lithium ion migration number of 0.78, and the Lewis acid sites provided by YSZ can synergistically promote the ring opening polymerization of DOL with Al (OfT)3, resulting in a DOL monomer conversion rate of 98.2%. In addition, because of the introduction of YPVDF nanofibers, the heat-resistant decomposition temperature of PDOL@YPVDF-CSE increased to 312 ℃. A symmetric lithium battery assembled as Li| PDOL@YPVDF-CSE |Li was capable of stable cycling for over 1500 h. An assembled LiFeO4| PDOL@YPVDF-CSE | battery subjected to 800 cycles at a rate of 0.5C had a capacity retention rate of 97.4%, and after 500 cycles at a rate of 2C, the capacity retention rate was 96.8%. Meanwhile, the NCM622 | PDOL @ YPVDF-CSE | Li battery assembled with LiNi0.6Co0.2Mn0.2O2 (NCM622) as the positive electrode had a capacity retention rate of 96.2% after 150 cycles at a rate of 1C.

Key words: coaxial electrospinning, poly(1,3-dioxolane), in situ polymerization, electrochemical performance, composite solid electrolyte

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