A Fluorinated Solid‐state‐electrolyte Interface Layer Guiding Fast Zinc‐ion Oriented Deposition in Aqueous Zinc‐ion Batteries

Abstract Aqueous zinc ion batteries are gaining popularity due to their high energy density and environmental friendliness. However, random deposition of zinc ions on the anode and sluggish migration of zinc ions on the interface would lead to the growth of zinc dendrites and poor cycling performance. To address these challenges, we developed a fluorinated solid‐state‐electrolyte interface layer composed of Ca 5 (PO 4 ) 3 F/Zn 3 (PO 4 ) 2 via an in situ ion exchange strategy to guide zinc‐ion oriented deposition and fast zinc ion migration on the anode during cycling. The introduction of Ca 5 (PO 4 ) 3 F (FAP) can increase the nucleation sites of zinc ions and guide the oriented deposition of zinc ions along the (002) crystal plane, while the in situ formation of Zn 3 (PO 4 ) 2 during cycling can accelerate the migration of zinc ions. Benefited from our design, the assembled Zn//V 2 O 5 ⋅ H 2 O batteries based on FAP‐protected Zn anode (FAP‐Zn) achieve a higher capacity retention of 84 % (220 mAh g −1 ) than that of bare‐Zn based batteries, which have a capacity retention of 23 % (97 mAh g −1 ) at 3.0 A g −1 after 800 cycles. This work provides a new solution for the rational design and development of the solid‐state electrolyte interface layer to achieve high‐performance zinc‐ion batteries.