Electrochromism

About: Electrochromism is a research topic. Over the lifetime, 13097 publications have been published within this topic receiving 294637 citations.

Photoresponsive Smart Coloration Electrochromic Supercapacitor.

Abstract: Electrochromic devices have been widely adopted in energy saving applications by taking advantage of the electrode coloration, but it is critical to develop a new electrochromic device that can undergo smart coloration and can have a wide spectrum in transmittance in response to input light intensity while also functioning as a rechargeable energy storage system. In this study, a photoresponsive electrochromic supercapacitor based on cellulose-nanofiber/Ag-nanowire/reduced-graphene-oxide/WO3 -composite electrode that is capable of undergoing "smart" reversible coloration while simultaneously functioning as a reliable energy-storage device is developed. The fabricated device exhibits a high coloration efficiency of 64.8 cm2 C-1 and electrochemical performance with specific capacitance of 406.0 F g-1 , energy/power densities of 40.6-47.8 Wh kg-1 and 6.8-16.9 kW kg-1 . The electrochromic supercapacitor exhibits excellent cycle reliability, where 75.0% and 94.1% of its coloration efficiency and electrochemical performance is retained, respectively, beyond 10 000 charge-discharge cycles. Cyclic fatigue tests show that the developed device is mechanically durable and suitable for wearable electronics applications. The smart electrochromic supercapacitor system is then integrated with a solar sensor to enable photoresponsive coloration where the transmittance changes in response to varying light intensity.

Electrochromic media with concentration-enhanced stability, process for the preparation thereof and use in electrochromic devices

Abstract: Increased stability of electrochromic devices containing an electrochromic medium having two or more electroactive compounds is accomplished by establishing current limiting concentrations of electroactive compounds with the larger redox potential difference. A process for production of electrochromic devices uses targeted concentrations of electroactive materials during preparation of the electrochromic medium which results in substantially no devices being produced wherein the current is limited by an electroactive compound having a low redox potential difference.

Transmission Spectra of an Electrochromic Window Based on Polyaniline, Prussian Blue and Tungsten Oxide

Abstract: The demand for energy savings in buildings will increase in the coming years, as the world`s attention is drawn towards environmental aspects and energy economizing. Windows which are able to dynamically control the sun radiation throughput will play an important role. In this respect, the authors have studied two different electrochromic window configurations; one based on the two complementary electrochromic materials polyaniline (PANI) and tungsten oxide (WO{sub 3}), the other one with the electrochromic coating Prussian blue (PB) in addition to PANI and WO{sub 3}. The inclusion of PB enhances the transmission modulation. Integrating over the solar spectrum they find that the window based on PANI and WO{sub 3} is able to regulate 39% of the total solar energy, while with the inclusion of PB they manage to regulate as much as 50% of the sun radiation.

Transparent Zinc-Mesh Electrodes for Solar-Charging Electrochromic Windows

Abstract: Newly born zinc-anode-based electrochromic devices (ZECDs), incorporating electrochromic and energy storage functions in a single transparent platform, represent the most promising technology for next-generation transparent electronics. As the existing ZECDs are limited by opaque zinc anodes, the key focus should be on the development of transparent zinc anodes. Here, the first demonstration of a flexible transparent zinc-mesh electrode is reported for a ZECD window that yields a remarkable electrochromic performance in an 80 cm2 device, including rapid switching times (3.6 and 2.5 s for the coloration and bleaching processes, respectively), a high optical contrast (67.2%), and an excellent coloration efficiency (131.5 cm2 C-1 ). It is also demonstrated that such ZECDs are perfectly suited for solar-charging smart windows as they inherently address the solar intermittency issue. These windows can be colored via solar charging during the day, and they can be bleached during the night by supplying electrical energy to electronic devices. The ZECD smart window platform can be scaled to a large area while retaining its excellent electrochromic characteristics. These findings represent a new technology for solar-charging windows and open new opportunities for the development of next-generation transparent batteries.