Highly stable Ah-level Zn-iodine batteries enabled by physical shielding and interface electronic reconstruction

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Stable solid electrolyte interphase (SEI) construction is crucial for zinc anodes to inhibit side reactions and ensure uniform zinc deposition.
• Existing SEI layers allow proton (H+) migration, leading to hydrogen evolution reactions (HER) and anode corrosion, limiting battery performance.

Purpose of the Study:

• To in-situ construct a hierarchical multifunctional SbZn and ZnF2 interface layer (SZZF) on the zinc anode.
• To address challenges of HER and corrosion in aqueous zinc batteries by optimizing the anode-electrolyte interface.

Main Methods:

• In-situ construction of a SZZF interface layer comprising an outer ZnF2-rich and inner SbZn alloy-rich layer.
• Characterization of the SZZF layer's properties, including hydrophobicity and its effect on Zn2+ desolvation and Zn-H+ bonding.
• Electrochemical testing of SZZF@Zn symmetric cells and SZZF@Zn||I2 full cells under various conditions.

Main Results:

• The SZZF layer effectively homogenizes Zn2+ flux and suppresses HER activity through d-p hybridization.
• SZZF@Zn symmetric cells demonstrated exceptional cycling durability up to 7000 hours and over 550 hours at 85% DOD.
• SZZF@Zn||I2 full cells maintained 97% capacity after 50,000 cycles, and a 1.65 Ah pouch battery cycled over 115 times.

Conclusions:

• The developed SZZF interface layer is a feasible and efficient strategy for optimizing zinc anodes.
• This approach significantly enhances the cycling stability and reversibility of aqueous zinc iodine batteries.
• The study presents a promising pathway for developing high-performance and durable aqueous rechargeable batteries.