Binary Electrolyte Additive-Reinforced Interfacial Molecule Adsorption Layer for Ultra-Stable Zinc Metal Anodes

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc ion batteries (AZIBs) are promising for sustainable energy storage.
• Key challenges include Zn anode instability, hydrogen evolution reaction (HER), and dendrite growth.
• These issues limit the cycle life and safety of AZIBs.

Purpose of the Study:

• To develop a stable interfacial layer for Zn anode protection in AZIBs.
• To suppress HER and prevent dendrite formation.
• To enhance the overall performance and longevity of AZIBs.

Main Methods:

• Introduction of a natural binary additive: saponin and anisaldehyde.
• Reshaping the electric double layer (EDL) structure for interfacial adsorption.
• Investigating intermolecular hydrogen bonding between saponin and anisaldehyde.
• Analyzing the electrocatalytic coupling of anisaldehyde with H* for HER suppression.
• Verifying the structural evolution of anisaldehyde during Zn deposition.

Main Results:

• Formation of a robust inorganic solid electrolyte interphase (SEI).
• Zn||Zn symmetric cells achieved ultra-long cycling: 3400 h at 1 mA cm⁻² and 1700 h at 10 mA cm⁻².
• Reversible operation for 450 h at 20 mA cm⁻².
• Zn-ion hybrid capacitors demonstrated a lifespan of 100,000 cycles.

Conclusions:

• A simple, synergistic strategy effectively enhances anode/electrolyte interfacial stability.
• The saponin-anisaldehyde additive shows significant potential for protecting Zn anodes in high-performance AZIBs.
• This approach offers a pathway for developing safer and more durable aqueous energy storage systems.