High-Performance Electrochromic Energy Storage Devices Based on Hexagonal WO₃ and SnO₂/PB Composite Films

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Electrochromic devices are crucial for smart energy storage systems and advanced electronics.
• Tungsten oxide (WO3) shows promise for multifunctional devices due to its electrochromic and pseudocapacitive properties.
• Efficient synthesis of high-performance WO3 electrochromic films remains a challenge.

Purpose of the Study:

• To develop an efficient and straightforward synthesis method for hexagonal-phase WO3 films.
• To fabricate high-performance electrochromic energy storage devices (EESDs).
• To enhance coloration efficiency and optical modulation in WO3-based devices.

Main Methods:

• A low-temperature hydrothermal approach was used for in situ growth of WO3 films on FTO substrates.
• Sorbitol was utilized to promote nucleation, and rubidium sulfate was used to regulate crystal growth.
• A composite PB/SnO2 film was designed as the anode to complement the WO3 cathode.

Main Results:

• The fabricated EESD demonstrated fast bleaching/coloration response.
• A high coloration efficiency of 101.2 cm² C⁻¹ was achieved.
• Significant optical property modulation (81.47% transmittance change) was observed, shifting from transparent to deep blue.

Conclusions:

• The one-step hydrothermal synthesis provides an efficient route to high-performance WO3 electrochromic films.
• The developed EESD exhibits excellent electrochromic and energy storage capabilities.
• This work advances the development of smart multifunctional electrochromic devices.