Reversible Metal Electrodeposition Enabled by Composites of PEDOT:PSS/MXene for Durable Smart Windows with Broadband Electromagnetic Wave Modulation.

Reversible metal electrodeposition (RME)-based electrochromic devices (ECDs) are promising candidates for smart windows due to their simple structure and cost-effectiveness. However, their performance is limited by unsatisfying cycling stability due to uneven metal deposition and metallic dendrite formation on the electrode. In this work, a PEDOT:PSS/MXene composite (PPM) is developed to modify ITO electrode surface. The PPM composite enhances the electrical conductivity and surface potential uniformity of ITO electrodes, guiding homogeneous Cu/Bi deposition. Moreover, the MXene component in PPM composite accelerates Cu/Bi deposition kinetics and suppresses dendrite formation. The PPM composites enable construction of large-area smart windows with multi-spectral electromagnetic wave modulation capabilities. The established PPM/ITO||Cu/Polyamide (PA6) exhibits stable cycling for 1,800 cycles in comparison to 970 cycles for bare ITO-based device. Additionally, the ECD in its colored state demonstrates a superior near-infrared blocking ability of T<10%@900-1700 nm and an X-band electromagnetic interference shielding effectiveness of 44.5 dB@8.2-12.4 GHz. The scalability of this strategy is further demonstrated through a large-area ECD (12 cm × 12 cm) featuring multi-state color switching. This work offers a facile and scalable approach to enhance the cycling stability of the RME-type ECDs and demonstrates great potential in broadband electromagnetic wave modulation toward multi-functional smart windows.