Ionic liquid-regulated stable interphase engineering toward long-life dendrite-free aqueous Zn-ion batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) offer safe and cost-effective large-scale energy storage.
• Parasitic reactions like hydrogen evolution and zinc dendrite growth limit AZIB cycle life.

Purpose of the Study:

• To develop a novel additive for aqueous electrolytes to enhance the stability and cycle life of zinc anodes.
• To elucidate the synergistic mechanism of the additive in regulating the zinc anode interface.

Main Methods:

• Utilized 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][DEP]) as an ionic liquid additive in aqueous electrolytes.
• Investigated the synergistic effects of the [DEP]⁻ anion and [EMIM]⁺ cation on solvation structure, interphase, and ion transport.
• Tested Zn||Zn symmetric cells and Zn||PANI full cells for cycling stability and capacity retention.

Main Results:

• The [EMIM][DEP] additive demonstrated a unique ternary synergistic optimization mechanism.
• Achieved over 5000 hours of stable cycling in Zn||Zn symmetric cells at 1 mA cm⁻².
• The Zn||PANI full cell retained 98.54% capacity after 2000 cycles.

Conclusions:

• The [EMIM][DEP] additive effectively suppresses parasitic reactions and zinc dendrite growth.
• The three-in-one synergistic mechanism provides a new strategy for designing high-performance AZIBs.
• This work offers insights for developing practical, long-lasting zinc-ion batteries.