Strong Dipole Inner Salt Molecule as Interface Ion Bridge for Rechargeable Aqueous Zn-Anode Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous electrolyte additives are crucial for improving zinc anode performance in batteries.
• The specific structural effects of additives on the electric double layer and zinc plating are not fully understood.

Purpose of the Study:

• To investigate the role of additive properties, such as dipole moment and functional groups, in modulating the zinc anode interface.
• To identify effective dipolar inner salt additives for enhancing zinc anode stability and plating kinetics.

Main Methods:

• Comparative analysis of various electrolyte additives with different compositions and polarities.
• Electrochemical testing of zinc anodes in aqueous electrolytes with selected additives.
• Characterization of electrode interfaces and plating morphology.

Main Results:

• Additive dipole moment significantly influences the electrode interface, while zincophilic groups are key for plating kinetics.
• L-α-glycerylphosphorylcholine, a strongly dipolar inner salt, effectively stabilizes the zinc anode surface and facilitates Zn2+ desolvation.
• The optimized electrolyte suppressed parasitic reactions and dendrite formation, achieving 99.8% Coulombic efficiency and 1800 hours of stable cycling.

Conclusions:

• Dipolar inner salt additives are promising for developing high-performance aqueous zinc batteries.
• Understanding the structure-property relationships of additives is essential for rational electrolyte design.
• L-α-glycerylphosphorylcholine offers a viable strategy for enhancing zinc anode durability and efficiency.