Electrochromic Devices Rapidly Changing Color for Supercapacitive and Pseudocapacitive Energy Storage
These polymers of intrinsic microporosity (PIMs) use electrochromic materials that change color in response to an applied voltage for improved energy storage. Electrochromic materials switch color when a voltage potential is applied. These materials are widely used in smart windows, displays, and advanced optics due to their electrochemical stability, moderate operating voltages, and high optical contrasts. However, existing electrochromic materials are constrained by slow switching speeds, limiting their effectiveness in next-generation devices and applications.
Researchers at the University of Florida have developed electrochromic materials that improve switching speeds while maintaining the key benefits of current materials. These materials are solution-processable PIMs, which are straightforward to manufacture and can be fabricated into thin films without the use of toxic solvents or transition metals. This technology represents a substantial improvement over current electrochromic systems and enables faster, safer, more energy-efficient display, window, and optic technologies.
Application
Fast-switching PIMs enable high-performance, energy-efficient electrochromic devices for smart windows, displays and advanced optics
Advantages
- Materials do not require conductive additive or stabilizing binder, significantly lowering the cost of manufacturing
- Scalable fabrication for large-area devices, accelerating production timeline
- Ability to be manufactured without toxic solvents, increasing safety of material
- Switching speeds of around one second represents a drastic advantage over other electrochromic materials in use today
Technology
This technology uses viologen-based polymers of intrinsic microporosity (PIMs) engineered for rapid electrochromic switching in solid-state devices. The PIMs are synthesized using contorted spirobisindane building blocks to create permanent nanoporous channels throughout the polymer matrix. These channels facilitate efficient ion transport and reduce charge transfer resistance, enabling swift and reversible color changes across the visible spectrum when a reductive bias is applied. The solution-processable nature of these PIMs allows for uniform thin-film deposition onto conductive substrates, forming two-terminal electrochromic devices with gel electrolytes. The materials demonstrate high optical contrast, elevated coloration efficiency, and robust cycling stability, all achieved without toxic solvents or transition metals. This combination of rapid switching, processability, and performance positions PIMs as a platform for next-generation mixed ionic-electronic conducting applications.
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