Self-Powered Smart Window is Also a Battery
new self-powered smart window coating able to change its tint in response to sunlight could also function as a rechargeable battery.
The coating consists of a liquid potassium chloride solution sandwiched between two layers of glass. A sheet of aluminum is attached to one of the glass pieces to make one electrode, while the other glass layer is coated with the electrochromatic material Prussian blue and forms the second electrode. Connecting the electrodes causes the blue pigment to become transparent in around four seconds, and detaching the electrodes will cause the material to return to blue in about the same amount of time.
As an added bonus, the design of the window also creates an electrochemical cell, which could be paired with another to provide enough power to light an LED. Detaching the cells will allow them to recharge by reacting with the oxygen in the air—essentially self-charging.