Molecularly Engineered Circular Additive with Multisite Desolvation for High-Performance Zinc Ion Battery

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Interface issues in aqueous zinc ion batteries (AZIBs) often lead to sluggish kinetics and polarization, especially under demanding conditions.
• Current additives can exacerbate these problems, highlighting the need for improved interface management.

Purpose of the Study:

• To establish a relationship between additive molecular structure and desolvation behavior in AZIBs.
• To identify design criteria for additives that promote fast desolvation and enhance battery performance.

Main Methods:

• Utilized a series of circular and linear sugar molecules as prototypes to study additive effects.
• Employed theoretical simulations and experimental validation to analyze molecular structure-desolvation relationships.
• Investigated the impact of additive properties like molecular size, steric configuration, and electronic structure.

Main Results:

• Circular fructose (FRU) demonstrated optimal properties for rapid desolvation due to its small size, quasi-planar configuration, and electron delocalization.
• FRU facilitated a compact electric double layer (EDL) with a shorter Zn2+ diffusion path and reduced activation energy.
• Achieved rapid interface kinetics and highly reversible zinc anodes over a wide temperature range.

Conclusions:

• Fructose acts as an effective additive for AZIBs by enabling fast desolvation and improving interface kinetics.
• Demonstrated exceptional performance in Zn//Zn cells (over 9500 h cycle life) and Zn//NVO cells (83.92% capacity retention after 2480 cycles) with lean electrolyte and high loading.