Multisite Cooperative Regulation of Solvation and Interface via Dynamic Additive Engineering for Highly Reversible...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) require additives to improve reversibility.
• The precise structure-performance relationship of additives, especially concerning solvation and interface regulation, is not well understood.
• Existing additives often lack synergistic control over both the electrolyte solvation shell and the electrode interface.

Purpose of the Study:

• To elucidate the dynamic configuration reconstruction mechanism of polyhydroxy additives in AZIBs.
• To establish a structure-performance relationship for multifunctional-group molecules (MGMs) as additives.
• To demonstrate how MGMs synergistically regulate solvation and interface for enhanced battery performance.

Main Methods:

• Synthesis and characterization of a series of polyhydroxy additive prototypes (MGMs).
• Electrochemical testing of Zn//Zn and Zn//PANI cells with MGMs.
• In-situ/operando studies to investigate the dynamic configuration changes of MGMs and their interaction with Zn2+ ions and the Zn anode interface.

Main Results:

• Increased functional groups and chain flexibility in MGMs correlate with improved battery performance.
• MGMs with folded configurations minimize active water in the solvation shell, suppressing parasitic reactions.
• MGMs transition to straight-chain architectures for parallel adsorption on the Zn anode, enhancing desolvation and promoting (002)-facet-dominated Zn deposition.

Conclusions:

• A dynamic configuration reconstruction mechanism for MGMs effectively regulates solvation and interface in AZIBs.
• MGMs enable long cycle life (7000 h for Zn//Zn) and subzero-temperature operation.
• This study opens new avenues for designing high-performance aqueous zinc-ion batteries through dynamic additive engineering.