Cationic Additive with a Rigid Solvation Shell for High-Performance Zinc Ion Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc ion batteries (AZIBs) face challenges with zinc metal anode stability due to dendritic growth and parasitic reactions.
• Developing reliable zinc anodes is crucial for advancing AZIB technology.

Purpose of the Study:

• To investigate the use of scandium (Sc3+) as an electrolyte additive to improve zinc metal anode performance in AZIBs.
• To understand the mechanism behind uniform zinc deposition induced by Sc3+.

Main Methods:

• Exploiting the tip-blocking effect of Sc3+ ions in the electrolyte to guide zinc deposition.
• Quantifying the rigidity of the Sc3+ hydration shell using the exchange reaction rate constant (kex).
• Testing the performance of Sc3+-modified anodes under various conditions, including low temperatures and organic solvent blends.

Main Results:

• Sc3+ additive effectively suppresses dendritic growth and promotes uniform zinc deposition.
• Hydration shell rigidity of Sc3+, quantified by kex, is identified as a key factor for the tip-blocking effect.
• The tip-blocking effect of Sc3+ is robust in mixed electrolytes and enables stable cycling at -40°C without corrosion.

Conclusions:

• Sc3+ is a promising additive for enhancing the long-term cycling stability of zinc anodes in AZIBs.
• Hydration shell rigidity offers a new metric for evaluating cation additives for uniform metal deposition.
• The developed strategy paves the way for reliable and high-performance AZIBs under demanding conditions.