Molecular‐Level Zn‐Ion Transfer Pump Specifically Functioning on (002) Facets Enables Durable Zn Anodes

Abstract The modification of metallic Zn anode contributes to solving the cycling issue of Zn‐ion batteries (ZIBs) by restraining the dendrite growth and side reactions. In this regard, modulating (002) Zn is an effective way to prolong the lifespan of ZIBs with a parallel arrangement of Zn deposition. Herein, the authors propose to add trace amounts of Zn(BF 4 ) 2 additive in 3 M ZnSO 4 to promote in‐plane Zn deposition by forming a BF 4 − ‐[Zn(H 2 O) 6 ] 2+ ‐[Zn(BF 4 ) 3 ] − transfer process and specifically functioning on (002) facets. In this way, the optimized electrolyte highly boosts the cycling stability of Zn anodes with a long lifespan at 34.2% Zn utilization (500 h/10 mA cm −2 ) and 51.3% Zn utilization (360 h/10 mA cm −2 ; 834 h/1 mA cm −2 ). Moreover, the electroplated Zn on Cu substrate exhibits a competitive cumulative plating capacity (CPC) of 2.87 Ah cm −2 under harsh conditions. The assembled Zn|(NH 4 ) 2 V 6 O 16 ·3H 2 O full cells with a high cathode loading of 29.12 mg cm −2 also realizes almost no capacity degradation even after 2000 cycles at 2 A g −1 . With this cost‐effective strategy, it is promising to push the development of aqueous ZIBs as well as provide inspiration for metal anode optimization in other energy storage systems.