A Polyzwitterionic "Ion-Sponge" Interphase via In Situ Self-Polymerization for Ultradurable Zinc Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc batteries offer grid storage potential but face limitations from side reactions and dendrite growth.
• Controlling the solid-electrolyte interphase (SEI) is crucial for enhancing zinc battery performance and lifespan.

Purpose of the Study:

• To design and implement a polyzwitterionic 'ion-sponge' interphase for aqueous zinc batteries.
• To improve zinc deposition uniformity and ion transport kinetics at the electrode-electrolyte interface.

Main Methods:

• In-situ self-polymerization of zwitterion monomers induced by an electric field.
• Formation of a hybrid SEI layer composed of polyzwitterions, ZnF2, and ZnS.
• Electrochemical characterization of Zn||Zn symmetric cells and full cells with V2O5 cathodes.

Main Results:

• The polyzwitterionic interphase effectively excluded water and enriched anions, facilitating in-situ anion conversion.
• Achieved a 100-fold increase in interfacial Zn2+ diffusion coefficient (1.9 × 10^-4 cm2 s^-1).
• Demonstrated stable cycling of Zn||Zn symmetric cells for over 1000 hours and full cells for 1900 cycles with high Coulombic efficiency.

Conclusions:

• The 'ion-sponge' interphase concept significantly enhances interfacial ion transport and suppresses dendrite formation in aqueous zinc batteries.
• This strategy enables high-performance, stable, and low-temperature operation of zinc-based energy storage systems.
• Provides a new pathway for interfacial engineering in advanced battery technologies.