刚柔并济聚氨酯基固态聚合物电解质

Rigid-flexible Coupling Solid Polymer Electrolytes Based on Polyurethane

  • 摘要: 采用聚乙二醇(PEG2000)与对苯二异氰酸酯(PDI)及六亚甲基二异氰酸酯(HDI)嵌段共聚反应制备聚氨酯基体材料,向其中掺杂锂盐,制得固态聚合物电解质,并对所得材料进行了结构表征和电化学性能测试。结果表明:共聚反应降低了PEG的结晶度,使固态电解质的室温离子电导率达7.4×10-5 S/cm。PDI的刚性及HDI的柔性在体系中均得以呈现,使固态电解质的拉伸强度达61.6 MPa,杨氏模量达62.9 MPa,断裂伸长率达65.6%,拉伸韧性达22.7 MJ/m3。利用所得固态电解质组装Li/LFP全固态锂金属电池,在0.1C倍率下循环100次后放电比容量为121.3 mAh/g,容量保持率为82%。

     

    Abstract: The polyurethane based polymer matrix was obtained from the block copolymerization between polyethylene glycol (PEG2000), 1, 4-phenylene diisocyanate (PDI) and hexamethylene diisocyanate (HDI), and the solid polymer electrolytes (SPEs) were fabricated by introducing lithium salts in the system additionally. The composition, structure and electrochemical properties of the prepared materials were also evaluated. The research results show that the crystallinity of PEG declines because of the copolymerization effect, which promotes the ionic conductivity of the prepared SPEs to be 7.4×10-5 S/cm at room temperature. Additionally, owing to the combination of the rigidity from PDI and the flexibility from HDI, the tensile strength is 61.6 mPa, Young's modulus is 62.9 mPa, elongation at break is 65.6%, and tensile toughness is 22.7 MJ/m3. The discharge capacity of the solid-state lithium metal batteries assembled by the fabricated SPEs reaches 121.3 mAh/g at 0.1C after 100 cycles, indicating nearly 82% of the capacity maintaining.

     

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