Researchers at the University of South Florida have invented electrochromic devices that use low power with improved cyclability of water-based organic electrolytes.
Electrochromic devices can change their color and opacity of a material when a voltage is applied. They have widespread applications in smart windows and displays as they can block ultraviolet and infrared light instantaneously and on-demand. Current innovations use 2.0 V voltage across a fluorine doped tin oxide (FTO) glass blade to change the gel from transparent to dark. However, this high voltage results in high power consumption in the electrochromic devices, and can electrolyze the water in the gel generating hydrogen and oxygen bubbles at voltages above 1.23 V.
Researchers at USF have developed electrochromic devices based on a single layer of composite gel material sandwiched between two conducting asymmetric electrodes (i.e., transparent conducting glass plates). This device reduces the voltage usage to less than 1.23 V and reduces the current from 70 mA to 14 mA due to the asymmetric features. Low voltage and low current usage of the device results in lower power usage. The lower voltage also prevents the electrolysis water in the gel, thereby leading to a long lifetime single gel-based electrochromic device.