Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
Homi Bhabha National Institute, Mumbai 400 094, India.
Phys Chem Chem Phys. 2023 Feb 1;25(5):3959-3968. doi: 10.1039/d2cp05811a.
Zeolitic imidazole frameworks (ZIFs) have emerged as potential conductive materials for Li ion-transport in polymer solid state electrolytes. However, developing ZIFs with high Li ionic conductivity is rather limited due to their flexible frameworks allowing dual ion conduction. Herein, we have used a mixed ligand strategy for fine-tuning the aperture and enhancing the rigidity of ZIF-8, which restricts the passage of large size anions. Poly(ethylene oxide)-based quasi-solid state electrolytes utilizing mixed ligand ZIF-7-8 frameworks as passive fillers show a continuous enhancement in Li ion-conductivity exclusively attributed to modifications in the flexibility and pore architecture of ZIF-8 as confirmed through broadband dielectric spectroscopy and positron annihilation spectroscopy. This study shows that polymer segmental relaxation and conductivity relaxation processes are decoupled in these electrolytes. Consequently, our proposed approach provides a new strategy for manufacturing a polymer-based electrolyte with enhanced ionic conductivity.
沸石咪唑骨架（ZIF）作为聚合物固态电解质中锂离子传输的潜在导电材料已经崭露头角。然而，由于其柔性框架允许双离子传导，因此开发具有高锂离子电导率的 ZIF 受到限制。在本文中，我们使用混合配体策略来微调孔径并增强 ZIF-8 的刚性，从而限制了大尺寸阴离子的通过。利用混合配体 ZIF-7-8 骨架作为惰性填料的基于聚环氧乙烷的准固态电解质表现出锂离子电导率的连续增强，这归因于 ZIF-8 的柔性和孔结构的改变，这通过宽频介电谱和正电子湮没谱得到了证实。这项研究表明，在这些电解质中，聚合物链段弛豫和电导率弛豫过程是解耦的。因此，我们提出的方法为制造具有增强离子导电性的聚合物电解质提供了一种新策略。
