Additive-Regulated Favorable Electrical Double Layer Facilitates the Trade-Off Between Kinetics and Reversibility for...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous Zinc ion batteries (AZIBs) are promising energy storage devices.
• Controlling the Zn/electrolyte interface is crucial for AZIB performance.
• Additive engineering offers a cost-effective strategy to enhance AZIBs.

Purpose of the Study:

• To investigate the effect of Diethoxydimethylsilane (DDS) as an additive in aqueous electrolytes for AZIBs.
• To understand how DDS regulates the electric double layer (EDL) at the Zn/electrolyte interface.
• To improve the cycling stability and Coulombic efficiency of AZIBs.

Main Methods:

• Experimental characterizations (e.g., electrochemical tests, surface analysis).
• Theoretical calculations (e.g., density functional theory).
• Fabrication and testing of Zn//Zn symmetrical and Zn//Cu asymmetrical cells.

Main Results:

• DDS additive preferentially adsorbs on the Zn surface, modifying the EDL.
• DDS prevents direct water-Zn contact, promoting uniform Zn deposition.
• Zn//Zn symmetrical cells showed >8750 h cycling stability at 0.5 mA cm⁻²/0.5 mAh cm⁻².
• Zn//Cu asymmetrical cells achieved 99.8% Coulombic efficiency over 5000 cycles.

Conclusions:

• DDS effectively regulates the EDL, enhancing Zn deposition/dissolution kinetics and reversibility.
• The optimized DDS concentration suppresses side reactions and Zn dendrite formation.
• DDS is a promising additive for developing high-performance and durable AZIBs.