Designing Cost-Effective Molecule-Substitution-Induced Anchoring Additives to Enable Stable Zinc-Ion Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) offer low cost and high safety but face challenges like dendrite growth and poor cycling stability.
• Key issues hindering AZIB performance include Zn2+ desolvation difficulties and undesirable side reactions at the electrode interface.

Purpose of the Study:

• To enhance the rate capability and cycling stability of AZIBs.
• To suppress zinc dendrite formation and improve Zn2+ deposition uniformity.
• To introduce a molecule-substitution-induced anchoring strategy using kojic acid.

Main Methods:

• Introduced kojic acid molecules containing C=O and C-OH groups to the electrolyte.
• Utilized the pyranone ring of kojic acid to form an adsorption layer on the Zn surface.
• Investigated the modulation of Zn2+ solvation structure and desolvation energy.

Main Results:

• Achieved an ultralong lifespan of 2800 h in a symmetric cell with 99.72% Coulombic efficiency at 1 mA cm-2.
• Demonstrated high capacity retention of 95% over 1500 cycles at 3 A g-1 in a Zn||δ-MnO2 full cell.
• Maintained a capacity of 197.9 mAh g-1 after 200 cycles at 50 °C, showcasing thermal stability.

Conclusions:

• Kojic acid effectively modulates Zn2+ solvation, lowers desolvation energy, and suppresses side reactions.
• The anchoring effect of kojic acid promotes uniform Zn deposition, preventing dendrite formation.
• The proposed strategy significantly improves the performance and durability of aqueous zinc-ion batteries.