In situ Detection of the Molecule-Crowded Aqueous Electrode-Electrolyte Interface

Area of Science:

• Electrochemistry
• Materials Science
• Surface Chemistry

Background:

• The electrode-electrolyte interface is critical for electrochemical device performance.
• Traditional X-ray photoelectron spectroscopy requires ultrahigh vacuum, limiting in-situ studies of dynamic interfaces, especially in aqueous solutions.

Purpose of the Study:

• To investigate the molecular evolution at the aqueous interface of a zinc metal anode using tender-energy ambient pressure X-ray photoelectron spectroscopy (AP-XPS).
• To understand how interface chemistry influences zinc deposition and battery stability.

Main Methods:

• Tender-energy ambient pressure X-ray photoelectron spectroscopy (AP-XPS) to analyze interfacial chemistry under near-ambient conditions.
• In situ optical microscopy and synchrotron radiation X-ray diffraction to observe zinc deposition morphology and crystal structure evolution.

Main Results:

• Additive molecules were found to prevent direct contact between zinc and water, promoting uniform zinc deposition.
• Uniform and dense zinc deposition was confirmed, linked to lateral growth driven by (002) crystal facet evolution.
• Batteries with the additive exhibited enhanced stability and reversibility in Zn//Zn, Zn//Cu, and full cell configurations.

Conclusions:

• AP-XPS is effective for studying dynamic interfacial evolution in aqueous environments.
• Additives play a key role in stabilizing zinc anodes by controlling interfacial chemistry and promoting uniform deposition.
• This work provides insights for designing stable aqueous ion battery anodes.