Heat-Insulating Black Electrochromic Device Enabled by Reversible Nickel-Copper Electrodeposition

Area of Science:

• Materials Science
• Electrochemistry
• Energy

Background:

• Electrochromic devices (ECDs) are promising for smart windows due to tunable light transmission.
• Existing black ECDs often have poor cycling stability and slow response times.
• Heat-insulating properties are crucial for energy-efficient smart windows.

Purpose of the Study:

• To develop a durable, heat-insulating black electrochromic device (ECD).
• To improve cycling stability and reduce coloration/bleaching times compared to existing ECDs.
• To evaluate the solar heat and infrared radiation blocking capabilities of the novel ECD.

Main Methods:

• Fabrication of a two-electrode ECD using a Ni-Cu alloy electrodeposition mechanism.
• Incorporation of a compatible gel electrolyte to enhance performance.
• Testing of cycling stability, transmittance modulation, coloration/bleaching times, and solar heat/infrared blocking.

Main Results:

• The Ni-Cu alloy ECD demonstrated 1500 cycles of stable operation.
• Achieved 55.2% transmittance modulation with short coloration (6.2 s) and bleaching (13.2 s) times.
• Efficiently blocked solar heat, reducing visible light transmittance to <5% (400-2000 nm) and blocking 35.0% of infrared radiation.

Conclusions:

• The developed Ni-Cu alloy ECD with gel electrolyte offers superior performance for smart window applications.
• The device provides excellent durability, rapid switching, and effective heat insulation.
• Potential applications include energy management, indoor human health, and indoor farming.