MOF-5对PEO基电解质导锂及界面稳定性能的改善  

Li-transfer promotion and interface stabilization of MOF-5 on PEO-based polymer electrolyte

作　　者：袁长福[1] 刘晋[1] 韩鹏飞[1] 徐俊毅[1] 李劼[1] 

机构地区：[1]中南大学冶金与环境学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2015年第4期1189-1196,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51274239)~~

摘　　要：以一种金属有机框架Zn4O(1,4-苯二甲酸)3(MOF-5)为填料,加入聚氧乙烯(Polyethylene oxide,PEO)中,以双三氟甲基磺酰亚胺锂(LiN(SO2CF3)2)为锂盐,通过溶液浇注法制备锂离子电池用复合电解质(Composite polymer electrolyte,CPE)膜。采用交流阻抗及其与电势阶跃相结合的方法分别对电解质的离子电导率和离子迁移数进行测定。另外,研究CPE与锂负极的界面稳定性以及计时电流曲线、阻抗随存储时间变化以及恒流极化循环曲线。研究结果表明:掺入质量分数为10%的MOF-5后,20℃时离子电导率从6.3×10-7 S/cm提高到最高的1.9×10-5S/cm,锂离子迁移数则随MOF-5质量分数的增加而增加,从质量分数为0时的0.012增加到20%时的0.232,表明MOF-5具有阴离子受体效应,对锂离子移动起到了很好的促进作用;MOF-5的加入明显提高了CPE与锂负极界面在静态存储及动态工作条件下的稳定性,进一步证明MOF-5能改善PEO基固体聚合物电解质关键性能。A kind of metal-organic framework Zn4O（1,4-benzenedicarboxylate）3（MOF-5） was employed as hybrid filler in poly（ethylene oxide）（PEO）-Li N（SO2CF3）2 based on composite polymer electrolyte（CPE） for lithium ion batteries. The CPE was prepared by using a solvent-casting method. The ionic conductivity was measured by AC impedance and the transference number by the AC impedance combined with a potential step measurement. When 10% MOF-5 is incorporated. In addition, the chronoamperometry, resistance stability upon storage and constant-current polarization were studied. The results show that the highest ionic conductivity of 1.9×10^-5 S/cm is obtained, which is 6.3×10^-7 S/cm without MOF-5 at 20 ℃. The lithium-ion transference number increases from 0.017 to 0.232 with the increase of mass fraction of MOF-5 from 0 to 20%, which suggests that the MOF-5 plays an anion receptor role in the electrolyte. The interfacial stability of CPE against lithium anode is significantly improved by MOF-5 under both storing and constant-current operating, indicating the application value of MOF-5 in PEO-based solid polymer electrolyte.

关 键 词：复合聚合物电解质 MOF-5 聚氧乙烯 阴离子受体 界面稳定性 锂离子电池 

分 类 号：O646[理学—物理化学]