Nanoarchitectonics of Two‐Dimensional Electrochromic Materials: Achievements and Future Challenges

Abstract Electrochromic effect has been discovered in many materials with a wide range of applications from visible to infrared, such as smart windows, electronic displays, infrared camouflage, and color‐changeable tactile sensor. However, conventional electrochromic materials cannot meet the growing demand for electrochromic performance in terms of optical contrast, response time, durability, color diversity, and flexibility, which slows down developments in this area. This is mainly due to the limited number and variety of electrochromic materials. In strong contrast, nanoarchitectonics of 2D materials with atomically thin thickness, large lateral size, and diversified series can be an effective way to address these issues and improve the electrochromic performances. This review highlights the recent achievements of emerging 2D electrochromic materials, namely covalent organic frameworks, coordination nanosheets, and transition metal carbides/nitrides/carbonitrides (MXenes). The structures, electrochromic performances and their structure–performance relationship, and future challenges of these materials have been systematically explored. This review can pave a new avenue for the promotion of the nanoarchitectonic 2D materials for the up‐scaled practical electrochromic applications.