Triple-Function Electrolyte Regulation toward Advanced Aqueous Zn-Ion Batteries.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries (ZIBs) suffer from poor zinc electrode reversibility, limiting their practical applications.
• Existing research has not fully elucidated the complex degradation mechanisms of zinc electrodes in aqueous electrolytes, including O2-involved corrosion, hydrogen evolution, and dendrite growth.

Purpose of the Study:

• To address the knowledge gap regarding zinc electrode behavior in aqueous media.
• To develop a strategy to overcome the limitations of zinc reversibility and enhance ZIB performance.

Main Methods:

• Investigated the O2-involved corrosion, H2 evolution, and dendrite growth of zinc electrodes in aqueous electrolytes.
• Introduced a triple-function electrolyte additive (C3H7Na2O6P) as a one-off strategy to improve battery performance during shelf time.
• Analyzed the regulation of H+ concentration and free-water activity by the additive.
• Examined the formation of a self-healing solid/electrolyte interphase (SEI) to suppress corrosion and dendritic deposition.

Main Results:

• Achieved a high zinc reversibility of 99.6% at an 85% discharge depth.
• Demonstrated a record lifespan for a pouch full-cell with capacity retention of 95.5% after 500 cycles using a lean electrolyte.
• Showcased the effectiveness of the additive in inhibiting H2 evolution and O2 adsorption corrosion.

Conclusions:

• The study provides deep insights into zinc behavior in aqueous media, identifying key degradation pathways.
• The developed electrolyte strategy effectively enhances zinc reversibility and battery lifespan.
• Established design principles for active metal anodes, including zinc and lithium, for improved performance during battery shelf time and real-world applications.