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

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.