High-Flux 3D Composite Polymer Electrolyte Enabling Dendrite-Free Zinc Deposition for Long-Life Zinc Metal Batteries

The development of polymer electrolytes for zinc metal batteries (ZMBs) is fundamentally constrained by the intrinsic trade-off between low ionic transport efficiency and poor interfacial stability. Herein, we present a high-flux composite polymer electrolyte (CPE) that is dendrite-free via an integrated strategy of 3D porous structure-organic/inorganic synergistic modification. Specifically, the 3D interconnected porous network, constructed through solvent casting, enables a liquid-phase assisted transport mechanism within mixed poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/PVDF polymers. Additionally, layered organo-montmorillonite (OMMT) optimizes ion transport kinetics, attributed from the Lewis acidic sites (Al–OH), significant nanosheet barriers, and as well as interfacial polarization. Consequently, the as-prepared CPEs achieve improved transference number of 0.38 and recorded critical current density of 6.7 mA·cm–2. Electrochemical tests show that the Zn||Zn symmetric cell delivers an ultralong cycling life of 5000 h at 0.1 mA·cm–2 (cumulative deposition capacity: 2.5 Ah·cm–2), and the Zn||Cu asymmetric cell maintains stable cycling over 6000 cycles at 0.5 mA·cm–2. In a practical demonstration, the Zn||I2 full battery retains 92.4% capacity after 1000 cycles at 0.5 A g–1. This work offers a rational design strategy for high-performance CPEs in ZMBs.