Stabilizing Zinc Anodes by Regulating the Electrical Double Layer with Saccharin Anions

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Zinc anodes exhibit poor Coulombic efficiency and dendrite formation due to unstable anode/electrolyte interfaces.
• The electrical double layer (EDL) structure's role in stabilizing the zinc anode's solid electrolyte interphase (SEI) is under-explored.

Purpose of the Study:

• To investigate saccharin as an electrolyte additive for regulating the EDL structure and stabilizing the zinc anode.
• To enhance the Coulombic efficiency and cycling stability of zinc anodes.

Main Methods:

• Introduction of saccharin as an electrolyte additive.
• Analysis of the EDL structure and SEI formation using electrochemical techniques.
• Testing of Zn|Zn symmetric cells and Zn-MnO2 full cells under various conditions.

Main Results:

• Saccharin-derived anions preferentially adsorb on the zinc surface, forming a water-poor EDL.
• A unique SEI layer is formed from saccharin decomposition products.
• Zn|Zn symmetric cells achieved 2.75 Ah cm⁻² cumulative capacity and 99.6% average Coulombic efficiency at 10 mA cm⁻².
• High rate performance was demonstrated at 40 mA cm⁻².

Conclusions:

• Saccharin effectively regulates the EDL and promotes stable SEI formation on zinc anodes.
• The proposed method significantly enhances the Coulombic efficiency and cycling stability of zinc-based batteries.
• Saccharin shows promise as a key additive for high-performance zinc batteries.