Deep eutectic solvent‐based gel electrolytes for flexible electrochromic devices with excellent high/low temperature durability

Abstract With the increasing interest in application of electrochromism to flexible and wearable electronics recent years, electrochromic devices (ECDs) that can function at extreme temperatures are required. However, functionalities ECDs severely hampered by inadequate choice electrolytes, which might ultimately result performance fading during low‐ high‐temperature operations. Here, we develop a deep eutectic solvent (DES)‐based gel electrolyte maintain its optical, electrical, mechanical properties over wide range (−40 150°C), exhibiting an extremely high visible‐range transmittance 90%, ion conductivity 0.63 mS cm −1 , fracture strain exceeding 2000%. Owing excellent processability DES‐based provided dynamic interactions such as lithium hydrogen bonding between DES polymer matrix, directly written patterning is realized for first time. The fabricated exhibit behavior superior with traditional electrolytes. introduction electrolytes expected pave way widespread products. image