Bifunctional Electrolyte Additives Modified Zinc Anode and Cathode.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries offer safety and sustainability but face anode and cathode degradation challenges.
• Hydrogen evolution and corrosion limit zinc anode performance.
• Cathode structural integrity is crucial for battery longevity.

Purpose of the Study:

• To investigate a novel electrolyte additive mixture for aqueous zinc-ion batteries.
• To enhance the stability of zinc anodes and mitigate cathode hydrolysis.
• To improve the overall performance and cycle life of zinc-ion batteries.

Main Methods:

• Utilized a mixed electrolyte comprising ZnSO₄, Zn(OTf)₂, and NH₄Cl.
• Incorporated bifunctional additives (Zn(OTf)₂ and NH₄Cl) to form a protective solid-electrolyte interphase (SEI).
• Tested symmetric and full cell batteries with NH₄V₄O₁₀ cathodes and zinc anodes.

Main Results:

• The additive mixture facilitated the formation of a stable SEI layer containing ZnF₂ and Zn₃N₂.
• Hydrolysis of the NH₄V₄O₁₀ cathode was effectively mitigated.
• Symmetric batteries demonstrated long-term stability at low (900 h at 1 mA cm^-2) and higher (570 h at 5 mA cm^-2) current densities.
• Full cells achieved 99.99% Coulombic efficiency over 2000 cycles at 1 A g^-1.

Conclusions:

• The bifunctional additive mixture significantly enhances the performance and stability of aqueous zinc-ion batteries.
• This approach offers a promising pathway for the practical application of advanced zinc-ion battery technology.
• The developed electrolyte system addresses key challenges in zinc-ion battery degradation.