Dual-cathode electrochromic smart window with a shared Zn anode for independent visible and near-infrared regulation

Dual-band electrochromic smart windows (DESWs) can realize multi-band regulation of solar spectrum, thereby playing a crucial role in achieving building energy conservation. However, independent control of visible (VIS) and near-infrared (NIR) lights for more intelligent indoor comfort is still a significant challenge. Herein, we present an innovative electrochromic smart window design employing a dual-cathode system of ultra-thin (∼80 nm) poly (3,4-(2,2-dimethylpropylenedioxy)thiophene) (PProDOT-Me 2 ) electrode and nanoporous Nb 18 W 16 O 93 electrode with a shared Zn anode, where PProDOT-Me 2 and Nb 18 W 16 O 93 electrodes are used for VIS and NIR control, respectively. Therefore, the Nb 18 W 16 O 93 /Zn/PProDOT-Me 2 device displays four distinct states with multiple color variations, including “bright” (colorless), “cool” (light blue), “warm” (blue-purple) and “dark” (dark blue). Unlike conventional cathode/anode complementary systems, the reversible switching between “bright” and “dark” states can be achieved through simultaneously tuning the color of PProDOT-Me 2 and Nb 18 W 16 O 93 cathodes by Zn anode, which reduces the switching voltages to −1.0 and 2.0 V in organic electrolyte, thereby achieving an excellent cycle performance. Moreover, potential differences between Zn anode and PProDOT-Me 2 /Nb 18 W 16 O 93 cathodes enable the device a self-operation mode by directly connecting the two electrodes with Zn anode, further decreasing energy consumption. This design offers a novel strategy for constructing DESWs with independent VIS and NIR regulation, thereby advancing the application of electrochromic technology in building energy conservation.