Low-Concentration Electrolytes toward High-Performance Aqueous Ammonium-Ion Electrochromic Devices

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Ammonium-ion electrochromic devices (AECDs) offer visible working states for intelligent electronics.
• Developing high-performance and stable AECDs with suitable electrolytes remains a challenge.

Purpose of the Study:

• To investigate the electrochemical and electrochromic properties of Prussian blue (PB) electrodes in various ammonium sulfate electrolytes.
• To optimize AECD performance through electrolyte concentration and electrode material selection.
• To enable real-time assessment of AECD operational status.

Main Methods:

• Systematic investigation of PB electrodes in different aqueous electrolytes and ammonium sulfate concentrations.
• Molecular dynamics simulations to understand ion diffusion.
• Assembly and testing of a quasi-solid-state AECD using PB and NbWO electrodes with hydrogel electrolytes.

Main Results:

• A 0.25 M ammonium sulfate electrolyte demonstrated optimal diffusion kinetics and electrochromic performance for PB electrodes.
• PB electrodes achieved 82.3% performance retention over 5000 cycles.
• The quasi-solid-state AECD exhibited 61.1% optical modulation and over 3000 cycles of stability.
• A quantitative relationship between optical characteristics and electrochemical reactions was established.

Conclusions:

• Low-concentration ammonium sulfate electrolytes are crucial for high-performance AECDs.
• The developed quasi-solid-state AECD shows significant potential for practical applications.
• Real-time operational state assessment of AECDs is now feasible, advancing intelligent electronic development.