An Interface‐Bridged Organic–Inorganic Layer that Suppresses Dendrite Formation and Side Reactions for Ultra‐Long‐Life Aqueous Zinc Metal Anodes

Abstract

Aqueous zinc (Zn) batteries (AZBs) are widely considered as a promising candidate for next‐generation energy storage owing to their excellent safety features. However, the application of a Zn anode is hindered by severe dendrite formation and side reactions. Herein, an interfacial bridged organic–inorganic hybrid protection layer (Nafion‐Zn‐X) is developed by complexing inorganic Zn‐X zeolite nanoparticles with Nafion, which shifts ion transport from channel transport in Nafion to a hopping mechanism in the organic–inorganic interface. This unique organic–inorganic structure is found to effectively suppress dendrite growth and side reactions of the Zn anode. Consequently, the Zn@Nafion‐Zn‐X composite anode delivers high coulombic efficiency (ca. 97 %), deep Zn plating/stripping (10 mAh cm−2), and long cycle life (over 10 000 cycles). By tackling the intrinsic chemical/electrochemical issues, the proposed strategy provides a versatile remedy for the limited cycle life of the Zn anode.

Regulating Zn Deposition via an Artificial Solid–Electrolyte Interface with Aligned Dipoles for Long Life Zn Anode

“…A certain amount of SO 4 2− anions could be rejected by the BTO layer due to the electrostatic repulsion. The interaction between cations and anions gets weak; then, the side reactions would be suppressed [ 42 ]. Additionally, the water molecules of hydrated zinc ion can be attracted by the element O of Ti–O, which enriches negative charges.…”

A Highly Reversible Zinc Anode for Rechargeable Aqueous Batteries

“…As shown in Figure d,e, the charge transfer resistance ( R ct ) of bare Zn is larger than that of Zn@SPEEK at different temperatures, indicating a lower energy barrier for Zn 2+ ion transfer and desolvation on the SPEEK interface. The activation energy of Zn@SPEEK is calculated to be only 45.0 kJ mol –1 (Figure f), compared to 57.8 kJ mol –1 of bare Zn, indicating that the improved Zn deposition on Zn@SPEEK is mainly attributed to the facilitated desolvation kinetics enabled by the strong interaction between solvated Zn 2+ ions and sulfonic acid groups. ,− Moreover, the SPEEK SEI features an ionic conductivity as high as 1.98 mS cm –1 in ZnSO 4 solution (Figure S5), which allows fast Zn 2+ ion transport through this protective layer. The transference number of Zn 2+ ions ( t Zn ) was further measured to evaluate the selectivity of the SPEEK layer.…”

“…, Al 2 O 3 and TiO 2 ) layers were coated on the surface of Zn metal anodes using the atomic layer deposition technique. , Although these layers could protect Zn anodes from side reactions, the inhibition effect was rather limited, possibly due to the low selectivity of ions and water and the poor mechanical strength which may easily cause breakage during repeated plating/stripping cycles. Alternatively, elastic polymers with enhanced mechanical properties, such as polyamide, commercial cyanoacrylate glue, and Nafion, were investigated as coating materials to improve the electrochemical performance of Zn anodes. Unfortunately, these polymers cannot meet the stringent requirements for an ideal SEI, which needs to have a high ionic conductivity and selectivity, good mechanical strength, and excellent stability in the aqueous electrolyte.…”

Anticatalytic Strategies to Suppress Water Electrolysis in Aqueous Batteries

“…Therein, the Zn 2+ would transfer through the coating and deposit beneath it so that the protective effect can last for a long time. In addition, the artificial SEI layer can also play the role of a physical barrier between the electrode and electrolytes; meanwhile, its electronic insulating nature may eradicate the electrochemical corrosion problem. − Related works will be introduced in section .…”

“…Artificial SEI layers have also been introduced over the Zn metal anode to prevent corrosion and the accompanying hydrogen evolution. − , For instance, a polyamide (PA)-based artificial SEI was designed to protect the Zn metal anode . The PA coating suppresses the side reactions via two mechanisms (Figure d).…”