Gradient Structured Separator Enables Stable Aqueous Zinc Metal Batteries

Developing a functional separator is an important strategy to improve the electrochemical performance of the Zn anode by suppressing the Zn dendrite growth and parasitic side reactions, thus advancing the aqueous zinc-ion batteries. Herein, we experimentally realize functional separator with gradient-structure based on CeF₃ nanoparticles functionalized glass fibers. The experimental and theoretical results confirmed that the functional separator can tailor the Zn²⁺ flux and restrain SO₄^2- transport, promoting dense Zn deposition. The strong interaction between CeF₃ nanoparticles and H₂O separates Zn²⁺ and H₂O at the electrolyte/Zn anode interface, suppressing side reactions. Consequently, the Zn||Zn with this separator achieves excellent cycling stability of 2500 h at 1 mA cm^-2 and 1 mAh cm^-2 and 1000 h at 5 mA cm^-2 and 5 mAh cm^-2. This design of a functionalized separator provides a distinctive solution for the development of aqueous zinc-ion batteries.