Angstrom‐Scale Confined Ion Sieve and Accelerator for Efficient Aqueous Zinc Batteries

Abstract

ABSTRACT The commercialization of aqueous zinc–metal batteries (AZMBs) is hindered by dendrite growth caused by uncontrolled Zn 2+ transport and side reactions involving water and anions. Here, an angstrom–scale confined ion sieve and accelerator is designed using unilamellar Ti 0.87 O 2 nanosheets with atomic Ti vacancies (∼3.0 × 3.8 Å) and interlayer spacing (∼3.5 Å) to enable selective Zn 2+ (∼1.5 Å) transport while blocking H 2 O (∼4.0 Å) and SO 4 2− (∼5.9 Å). This design facilitates selective Zn 2+ ion transport with high flux and Zn/SO 4 2− selectivity, effectively mitigating water–/anion–induced parasitic reactions at the Zn anode. Consequently, the Ti 0.87 O 2 @Zn anode exhibits significantly suppressed dendrite growth and parasitic side reactions during repeated Zn plating/stripping, with stable cycle lives exceeding 5000 and 4000 h at 1 and 5 mA cm −2 , respectively. The Ah–level Ti 0.87 O 2 @Zn//VO 2 pouch cell retains 85.4% of its initial capacity after 300 cycles at 3 A g −1 . This strategy provides a promising interfacial design concept for improving the reversibility of aqueous Zn metal anodes and may inspire the rational design of confined ion–transport interphases for related aqueous battery systems.