Hydrophilic-Zincophobic Separator Enabling by Crystal Structure Regulation toward Stabilized Zn Metal Anode

Aqueous zinc-ion batteries (ZIBs) hold significant promise for large-scale energy storage. While considerable strides have been made in modifying separators, the challenge of developing dendrite-free, corrosion-resistant, and cost-effective separators for achieving extended cycling performance of Zn anodes persists. In light of this, a TiO2 coating separator to mitigate interfacial corrosion and passivation reactions, thereby facilitating high-performance ZIBs is designed. This study delves into the influence of the loading amount and crystal phase of the TiO2 coating layers on separator modification. Zn symmetric cells employing the anatase TiO2-modified glass fiber (A-TiO2@GF) separator demonstrate superior Zn2+ ion transport kinetics in a mild ZnSO4 electrolyte, ensuring sustained long-term stability and uniform Zn deposition. Furthermore, the reduced hydrogen evolution reaction (HER) activity of A-TiO2 coatings curbs H+ ion migration, minimizing interfacial corrosion and HER. Consequently, the assembled Zn||CaV8O20 zinc-ion full cells demonstrate outstanding long-term durability and impressive specific capacity, boasting a discharge capacity of 142 mAh g-1 after 1000 cycles. This work introduces a straightforward interface engineering strategy for creating efficient separators in zinc-ion batteries, promoting uniform Zn deposition. An anatase TiO2 coating separator is designed and fabricated to mitigate interfacial corrosion and passivation reactions of Zn anode toward high-performance Zn ion batteries. When used in Zn||Zn symmetrical cells, the A-TiO2@GF separator enables smooth operation for over 2000 h under conditions of 2 and 2 mAh cm-2. image