Improvement of ionic conductivity of solid polymer electrolyte based on Cu-Al bimetallic metal-organic framework fabricated through molecular grafting  

基于Cu-Al双金属有机框架的分子接枝提高固体聚合物电解质的离子电导率

作　　者：Liu-bin SONG Tian-yuan LONG Min-zhi XIAO Min LIU Ting-ting ZHAO Yin-jie KUANG Lin JIANG Zhong-liang XIAO 宋刘斌;龙田源;肖敏之;刘敏;赵亭亭;匡尹杰;蒋琳;肖忠良(长沙理工大学化学与化学工程学院,长沙410114;长沙理工大学电力与交通材料保护湖南省重点实验室,长沙410114;宁波工程学院新能源学院,宁波315336)

机构地区：[1]College of Chemistry and Chemical Engineering,Changsha University of Science and Technology,Changsha 410114,China [2]Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation,Changsha University of Science and Technology,Changsha 410114,China [3]College of New Energy,Ningbo University of Technology,Ningbo 315336,China

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第9期2943-2958,共16页中国有色金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.21501015);the Hunan Provincial Natural Science Foundation,China(No.2022JJ30604);Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation,China(No.2022CL01)。

摘　　要：A composite solid electrolyte comprising a Cu-Al bimetallic metal-organic framework(CAB),lithium salt(LiTFSI)and polyethylene oxide(PEO)was fabricated through molecular grafting to enhance the ionic conductivity of the PEO-based electrolytes.Experimental and molecular dynamics simulation results indicated that the electrolyte with 10 wt.%CAB(PL-CAB-10%)exhibits high ionic conductivity(8.42×10~(-4)S/cm at 60℃),high Li+transference number(0.46),wide electrochemical window(4.91 V),good thermal stability,and outstanding mechanical properties.Furthermore,PL-CAB-10%exhibits excellent cycle stability in both Li-Li symmetric battery and Li/PL-CAB-10%/LiFePO4 asymmetric battery setups.These enhanced performances are primarily attributable to the introduction of the versatile CAB.The abundant metal sites in CAB can react with TFSI~-and PEO through Lewis acid-base interactions,promoting LiTFSI dissociation and improving ionic conductivity.Additionally,regular pores in CAB provide uniformly distributed sites for cation plating during cycling.为了提高聚环氧乙烷(PEO)基电解质的离子电导率,通过分子接枝工程制备了一种由Cu-Al双金属有机框架(CAB)、锂盐(LiTFSI)和聚环氧乙烷PEO组成的复合固体电解质。实验和分子动力学模拟结果表明,含有10%CAB(质量分数)的电解质(PL-CAB-10%)具有较高的离子电导率(60℃时为8.42×10-4 S/cm)、较大的Li+转移数(0.46)、较宽的电化学窗口(4.91 V)、良好的热稳定性和优异的力学性能。此外,PL-CAB-10%在Li-Li对称电池和Li/PL-CAB-10%/LiFePO4非对称电池中均表现出优异的循环稳定性。其性能提升主要归因于多功能CAB的引入。CAB中的丰富金属位点可以通过Lewis酸碱相互作用与TFSI-和PEO反应,这既促进了LiTFSI的解离,又提高了离子电导率。同时,CAB中的规则孔洞为阳离子均匀涂覆提供了均一的分散位点。

关 键 词：polyethylene oxide Cu−Al bimetallic metal-organic framework solid lithium metal battery molecular grafting ionic conductivity 

分 类 号：O646[理学—物理化学] TM912[理学—化学]