Highly Reversible Zn Anodes Achieved by Enhancing Ion-Transport Kinetics and Modulating Zn (002) Deposition.

Abstract

Uncontrolled dendrite growth and water-related side reactions in mild electrolytes are the main causes of poor cycling stability of zinc anodes, resulting in the deterioration of aqueous zinc-based batteries. Herein, a multifunctional fluorapatite (Ca5(PO4)3F) aerogel (FAG) interface layer is proposed to realize highly stable zinc anodes via the integrated regulation of Zn2+ migration kinetics and Zn (002) orientation deposition. Owing to the well-defined aerogel nanochannels and the rich Zn2+ adsorption sites resulting from the ion exchange between Ca2+ and Zn2+, the FAG interface layer could significantly accelerate the Zn2+ migration and effectively homogenize the Zn2+ flux and nucleation sites, thus promoting rapid and uniform Zn2+ migration at the electrode/electrolyte interface. Additionally, during the cycling process, the F atoms from FAG promote the in situ generation of ZnF2, which facilitates the manipulation of the preferred Zn (002) orientation deposition, thus efficiently suppressing dendrite growth and side reactions by combining with the above synergistic effects. Consequently, the FAG-modified Zn anode displays a stable cycle life of over 4000 h at 1 mA cm-2 and exhibits highly reversible Zn plating/stripping behavior. Meanwhile, the Zn||MnO2 full cells exhibit improved cycle stability over 2000 cycles compared with that of the bare Zn, highlighting the virtues of the FAG protective layer for highly reversible Zn anodes. Our work brings the insight in to stabilize Zn anodes and power the commercial applications of aqueous zinc-based batteries.