Electrochromic devices built with ionogel electrolytes are seen as a pivotal step toward the future of quasi-solid electrochromic devices, due to their striking properties like exceptional safety and high ionic conductivity. Yet, the poor mechanical strength of electrolyte of these devices remains a constraint that hampers their advancement. As a resolution, this research explores the use of a robust, transparent ionogel electrolyte, which is designed using an in situ microphase separation strategy. The ionogels are highly transparent and robust and exhibit excellent physicochemical stability, including a wide electrochemical window and high temperature tolerance. Benefitting from these properties, a high-performance electrochromic device is fabricated through in situ polymerization with the ionogels, PPRODOT as the electrochromic layer, and PEDOT: PSS as the ion storage layer, achieving high transmittance contrast (43.1%), fast response (1/1.7 s), high coloring efficiency (1296.4 cm2 C-1), and excellent cycling endurance (>99.9% retention after 2000 cycles). In addition, using ITO-poly(ethylene terephthalate) as flexible substrates, a deformable electrochromic device displaying high stability is realized, highlighting the potential use in functional wearables.
Keywords: electrochromic device; electrolyte; in situ microphase separation; ionic liquid; ionogel.
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