Rejuvenation of Electrochromic Devices

Area of Science:

• Materials Science
• Energy Storage
• Sustainable Technologies

Background:

• Electrochromic devices (ECDs) offer significant energy-saving potential, particularly in green buildings.
• A major limitation for ECDs is performance degradation caused by ion trapping during device cycling.
• This ion trapping phenomenon restricts the long-term viability and widespread adoption of ECD technology.

Purpose of the Study:

• To investigate the feasibility of rejuvenating degraded electrochromic devices (ECDs) using a heat treatment method.
• To elucidate the mechanism of trapped ion release in electrochromic films under thermal stress.
• To demonstrate the restoration of electrochromic performance in various ECD configurations.

Main Methods:

• Degraded electrochromic devices (ECDs) of different types (semi-solid-state, all-solid-state with amorphous WO3, all-solid-state with crystalline WO3) were subjected to controlled heat treatment.
• Ion release mechanisms within the electrochromic films were simulated and experimentally validated.
• Electrochromic performance, including optical modulation, was measured before and after heat treatment.

Main Results:

• Heat treatment effectively released trapped ions from the electrochromic layers in all tested ECD types.
• Semi-solid-state ECDs near failure at low temperatures regained initial performance after heating.
• All-solid-state ECDs utilizing amorphous and crystalline WO3 achieved 97.3% and 95.5% of initial optical modulation, respectively, post-annealing.

Conclusions:

• Heat treatment is a viable and effective method for rejuvenating degraded electrochromic devices (ECDs).
• This rejuvenation process significantly extends the operational lifespan of various ECD architectures.
• The findings offer practical solutions for enhancing the durability of ECDs, promoting sustainable and eco-friendly energy technologies.