Confined Polymer Electrolyte Synthesis in Porous Frameworks for Cold‐Climate Zinc‐Ion Batteries
Ruihe Yu, Yu Ma, Ning Zhang, Tianyu Qiu, Qing Jiang, Guangshan Zhu
Abstract
Abstract Solid polymer electrolytes (SPEs) are vital for zinc‐ion solid‐state batteries (ZSSBs) for dendrite suppression but face low‐temperature hurdles from poor ionic conductivity and crystallization. Here, a supramolecularly engineered SPE is constructed by in situ polymerization of 2‐ethyl‐2‐oxazoline (EtOx) within sulfonated porous aromatic frameworks (SPAFs), acting as macroinitiators and nanoconfined reactors. Resulting poly(2‐ethyl‐2‐oxazoline) (PEtOx) chains assemble with the SPAF via strong non‐covalent interactions, forming cohesive SPAF‐PEtOx (SPP) with interconnected ion transport pathways. −SO 3 − groups anchor Zn 2+ , while confined PEtOx chains modulate solvation dynamics, facilitating efficient Zn 2+ migration. SPE based on SPP embedded in polyvinylidene fluoride (PVDF) matrices (SPP@PVDF) achieves high ionic conductivity (5.04 × 10 −4 s cm −1 ) and a wide electrochemical window (2.74 V) at room temperature. A Zn || Zn symmetric battery exhibits stable plating/stripping over 3000 h, while a full Zn || V 2 O 5 battery retains capacity over 1000 cycles at −40 °C with no decay. Notably, the ionic conductivity of SPP@PVDF at −40 °C is 8‐fold higher than SPAF@PVDF, as PEtOx reduces Zn 2+ migration barriers. This work offers a molecular‐level strategy for designing cryogenically robust SPEs, advancing ZSSB technologies for extreme environments.