增塑剂对PEO基固态电解质电性能影响的研究

Effect of plasticizer on electrical properties of PEO based solid electrolyte

本文以PEO为聚合物电解质基底,研究了PE、TE、LN三种增塑剂对固态电解质离子电导率和界面阻抗的影响,结果显示:小分子PE会在溶剂烘干过程中挥发,不适用于溶剂挥发方式制备的电解质;TE与LN对聚合物链段运动有明显的提升效果,离子电导率随温度的变化幅度明显提高,当增塑剂量在40%时,80℃离子电导率能达到10-3以上,接近液态电解质水平;TE及LN都能降低对锂界面阻抗,但前者界面阻抗更小。以TE为增塑剂的固态电解质膜组装的磷酸铁锂固态电池在80℃、0.2C充放电,比容量为143mAh/g,循环30圈稳定,库伦效率保持98%以上。

This paper studies the effect of plasticizer on the ion conductivity and interfacial impedance of polymer electrolyte,which PEO was taken as basal polymer electrolyte and three plasticizer were PE,TE and LN.The result shows:PE which is micromolecule will be volatile during drying process,does not apply to the electrolyte plasticizing by means of solvent evaporation mode.TE and LN have obvious promotion effect on the movement of polymer chain segment.The ionic conductivity increases significantly with the rangeability of temperature.When the amount of plasticizer is 40%,the ionic conductivity can reach more than 10-3S/cm at 80℃,which is close to the level of liquid electrolyte.Both TE and LN can reduce interface impedance.The former has a smaller interface impedance.The Lfp-Li cell with this plasticizer has a charging and discharging efficiency exhibited>98%where the rate was fixed at 0.2 C,a relatively high capacity of≈143 mAh/g,and exhibits stable cycling for at least 30 cycles.