构筑星形化合物提升交联网络固态聚合物电解质性能

Constructing Star-Shaped Compound to Improve the Performance of Cross-Linked Solid Polymer Electrolytes

通过巯基-丙烯酸酯点击反应引发三羟甲基丙烷三(3-巯基丙酸酯)(TMPMP)或季戊四醇四-3-巯基丙酸酯(PETMP)分别与聚(乙二醇)甲基丙烯酸酯(PEGMA)进行UV辐照反应,制得星型化合物。TMPMP或PETMP为交联剂,PEGMA为星形化合物的支链。星形化合物的结构可通过变换不同的交联剂,并通过改变PEGMA的相对分子质量进行调节。将星形化合物掺入交联固态聚合物电解质中,固态电解质的机械性能、电化学性能均得到改善。固态电解质的拉伸强度达83.9 MPa,杨氏模量达180.4 MPa,断裂伸长率达49.9%,拉伸韧性达22.6 MJ/m^(3),室温离子电导率达2.8×10^(-5) S/cm。利用该固态电解质组装Li/LFP全固态锂金属电池,在0.1 C倍率下循环100次后剩余比容量为111.5 mAh/g,比容量保持率为77%。

The star-shaped compound was fabricated by a UV irradiation reaction between trimethylolpropane tris(3-mercaptopropionate)(TMPMP)or pentaerythritol tetrakis(3-mercaptopropionate)(PETMP)with the introduction of poly(ethylene glycol)methacrylate(PEGMA)follow the mechanism of thiol-acrylate click chemistry.Additionally,PETMP or TMPMP is used as the crosslinker in the system,and PEGMA is used as the branch chain of the star-shaped compound.The structure of the compound can be tuned by utilizing different crosslinker combined with varying the molecular weight of PEGMA,effectively.By blending the prepared star-shaped compound into a kind of cross-linked solid polymer electrolytes(SPEs),the mechanical and electrochemical performances of this SPEs are improved simultaneously.In particular,the tensile strength,Young s modulus,elongation at break,tensile toughness,and ionic conductivity at room temperature of the product is 83.9 MPa,180.4 MPa,49.9%,22.6 MJ/m^(3),and 2.80×10^(-5) S/cm,respectively.The discharge capacity of the solid-state lithium metal batteries assembled by the fabricated SPEs reaches 111.5 mAh/g at 0.1 C after 100 cycles,indicating nearly 77%of the capacity maintaining.