Jin Biyu, Wang Dongyun, He Yuan, Mao Jianjiang, Kang Yunqing, Wan Chao, Xia Wei, Kim Jeonghun, Eguchi Miharu, Yamauchi Yusuke
School of Chemistry and Chemical Engineering, Anhui Key Laboratory of Coal Clean Conversion and High Valued Utilization, Anhui University of Technology Maanshan 243002 China
Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin Austin Texas 78712 USA.
Chem Sci. 2023 Jun 21;14(29):7956-7965. doi: 10.1039/d3sc01647a. eCollection 2023 Jul 26.
Composite polymer electrolytes (CPEs) with high ionic conductivity and favorable electrolyte/electrode interfacial compatibility are promising alternatives to liquid electrolytes. However, severe parasitic reactions in the Li/electrolyte interface and the air-unstable inorganic fillers have hindered their industrial applications. Herein, surface-edge opposite charged Laponite (LAP) multilayer particles with high air stability were grafted with imidazole ionic liquid (IL-TFSI) to enhance the thermal, mechanical, and electrochemical performances of polyethylene oxide (PEO)-based CPEs. The electrostatic repulsion between multilayers of LAP-IL-TFSI enables them to be easily penetrated by PEO segments, resulting in a pronounced amorphous region in the PEO matrix. Therefore, the CPE-0.2LAP-IL-TFSI exhibits a high ionic conductivity of 1.5 × 10 S cm and a high lithium-ion transference number of 0.53. Moreover, LAP-IL-TFSI ameliorates the chemistry of the solid electrolyte interphase, significantly suppressing the growth of lithium dendrites and extending the cycling life of symmetric Li cells to over 1000 h. As a result, the LiFePO||CPE-0.2LAP-IL-TFSI||Li cell delivers an outstanding capacity retention of 80% after 500 cycles at 2C at 60 °C. CPE-LAP-IL-TFSI also shows good compatibility with high-voltage LiNiCoMnO cathodes.
具有高离子电导率和良好电解质/电极界面相容性的复合聚合物电解质（CPE）是液体电解质很有前景的替代品。然而，锂/电解质界面处严重的寄生反应以及对空气不稳定的无机填料阻碍了它们的工业应用。在此，将具有高空气稳定性的表面-边缘带相反电荷的锂皂石（LAP）多层颗粒与咪唑离子液体（IL-TFSI）接枝，以提高聚环氧乙烷（PEO）基CPE的热性能、机械性能和电化学性能。LAP-IL-TFSI多层之间的静电排斥使PEO链段能够轻松穿透它们，从而在PEO基体中形成明显的非晶区。因此，CPE-0.2LAP-IL-TFSI表现出1.5×10 S cm的高离子电导率和0.53的高锂离子迁移数。此外，LAP-IL-TFSI改善了固体电解质界面的化学性质，显著抑制了锂枝晶的生长，并将对称锂电池的循环寿命延长至1000小时以上。结果，LiFePO||CPE-0.2LAP-IL-TFSI||Li电池在60℃下以2C倍率循环500次后，容量保持率高达80%。CPE-LAP-IL-TFSI与高压LiNiCoMnO正极也表现出良好的相容性。
