Hydrogen-bond-regulated antifreezing PVA/CMC quasi-solid electrolyte for dendrite-free and low-temperature stable Zn-ion batteries

A hydrogen-bond-regulated PVA/CMC quasi-solid-state electrolyte with EG/H 2 O solvent was designed to realize antifreezing and dendrite-free aqueous Zn-ion batteries. • The synergistic polymer network and EG effectively reduced free-water activity, optimized Zn 2+ solvation, and enabled uniform Zn deposition. • COMSOL simulations and experimental analyses confirmed that the quasi-solid-state electrolyte homogenized the interfacial electric field and suppressed dendrite growth. • The Zn||Zn symmetric cell achieved a long cycling lifespan of 1100 h at room temperature and 1700 h at −30 °C. Aqueous zinc-ion batteries (AZIBs) have attracted extensive attention owing to their intrinsic safety, low cost, and environmental benignity. However, the practical application of AZIBs is severely hindered by the freezing of aqueous electrolytes at low temperatures and by uncontrolled Zn 2+ deposition, which induces dendrite growth. Herein, a freeze-resistant quasi-solid-state gel electrolyte is proposed, in which poly (vinyl alcohol) (PVA) and carboxymethyl cellulose (CMC) form a robust three-dimensional network via hydrogen bonding and chain entanglement. Ethylene glycol (EG) regulates the solvation environment by confining free water molecules, thereby depressing the freezing point and stabilizing the Zn 2+ solvation structure, enabling efficient ion transport at low temperatures. COMSOL Multiphysics (COMSOL) further confirms that the quasi-solid-state electrolyte effectively homogenizes the electric field distribution, suppresses dendrite growth, and mitigates interfacial corrosion. Benefiting from these synergistic effects, Zn||Zn symmetric batteries deliver a prolonged cycling lifespan of 1100 h at 1 mA cm –2 and 1 mAh cm –2 , which is 12 times longer than that of the ZnCl 2 electrolyte. Notably, an ultralong lifespan of 1700 h is achieved at -30 °C. Furthermore, the Zn||V 2 O 5 full cell exhibits outstanding cycling stability over 2000 cycles at 1 A g –1 . This work provides a promising strategy for designing antifreezing electrolytes and stabilizing Zn anodes for high-performance AZIBs under extreme conditions. Download: Download high-res image (278KB) Download: Download full-size image