Empowering Zero‐Energy Buildings with Cutting‐Edge Self‐Powered Electrochromic Smart Window Technology

The development of energy‐efficient window technology is crucial for zero‐energy building approaches, as windows play a pivotal role in minimizing heat loss, optimizing natural light utilization, and contributing to overall energy conservation. In this study, a self‐powered electrochromic smart window is presented together and its application as a self‐charging battery is showcased. The self‐powered system is composed of a WO x electrochromic working electrode, an Al counter electrode, and an AlCl 3 liquid electrolyte similar to a voltaic cell. This device generates an open circuit voltage of around 0.95 V. When two electrodes are connected, this voltage is applied as an external voltage and changes the color of the transparent WO x electrode into a blue state with approximately 62% transmittance modulation. However, if the two electrodes are connected via an light‐emitting diode (LED), the LED lights up for up to 4 h.