Durable and flexible zinc mesh anodes for scalable and fast-switching electrochromic devices

Zinc anode-based electrochromic devices (ZECDs) represent a new generation of multifunctional electrochromic (EC) platforms, offering cost-effectiveness and high round-trip efficiency. However, their practical application remains limited due to the electric field inhomogeneity and the growth of Zn dendrites, issues primarily caused by the use of opaque peripheral Zinc (Zn) foils. Herein, we rationally designed a transparent (T = 71.4% @633 nm), durable, and flexible Ag-PVDF (polyvinylidene difluoride) coated Zinc (AP@Zn) mesh electrode. The AP@Zn mesh promotes a homogeneous electric field and potential distribution within ZECDs, exhibits excellent corrosion resistance, and possesses a low activation energy (47.59 kJ mol−1). Furthermore, it demonstrates broad compatibility with various EC electrodes. As a result, a 5 cm × 5 cm Prussian blue (PB)//AP@Zn achieved fast switching times (tc/tb 2.8 s/2.6 s), high coloration efficiency (157.44 cm2 C−1), outstanding cycling stability (93.7% ΔT retention after 500 cycles), and integrated energy storage functionalities (32.89 mA h m−2 at 0.02 mA cm−2). A large, scalable 10 cm × 10 cm PB//AP@Zn device showed significantly faster switching times (tc/tb 6.6 s/5.4 s) compared to the PB//Zn foil counterpart (tc/tb 15 s/11.4 s). Importantly, we also demonstrated devices based on Nb18W16O93 (NWO)//AP@Zn, which exhibited fast switching (tc/tb 18.5 s/20 s) and high durability (77.7% ΔT retention after 1200 cycles), as well as potassium vanadate (KVO)//AP@Zn featuring multicolor capabilities. Stacked PB//AP@Zn//KVO electrochromic displays exhibited a six-color palette including olive green1, tawny, bronzing, olive green2, deep blue-green, and cool grayish green. This work underscores the critical role of electrode design in advancing ZECDs towards multifunctional and flexible electronics.