Tailoring Ce-Centered Metal–Organic Frameworks for Fast Li<sup>+</sup> Transport in Composite Polymer Electrolyte
Liyuan Wang, Lingli Dong, Liyuan Xie, Zhi‐Tao Wang, Linpo Li, Enbo Shangguan, Jing Li
Abstract
Regulating metal nodes to innovate the metal–organic framework (MOF) structure is of great interest to boost the performance of MOFs-incorporated composite solid electrolytes. Herein, Ce 4+ with a low-lying 4f orbital is selected as metal center to coordinate with organic ligand to prepare MOF of Ce-UiO-66. The unsaturated open metal sites and defected oxygen vacancies furnish Ce-UiO-66 with strengthened Lewis acidity, which promotes Ce-UiO-66 interacting effectively with both poly(ethylene oxide) (PEO) and Li salt anions. Accordingly, Ce-UiO-66 as additive fillers can be uniformly dispersed in PEO matrix to form an advanced composite solid-state electrolyte (Ce-UiO@PEO) with accelerated Li + transport. The optimized Ce-UiO@PEO displays a boosted ionic conductivity of 4.20 × 10 –4 S cm –1 and an improved Li + transference number of 0.39 at 60 °C, which are highly comparable to those of other MOFs@PEO electrolytes. Combined with the mechanical and thermal stabilities, such a Ce-UiO@PEO electrolyte enables Li/Li symmetric and Li/LiFePO 4 full cells with superior cycling stability and rate performance. The Ce-UiO@PEO electrolytes are of great potential to be applied in high-performance lithium metal batteries.