The developments of modern surveillance technology pose great challenges to combat concealment for warfighters. Traditional camouflage suits cannot accommodate the need for camouflage stealth in complex warfare scenarios. Herein, a bidirectional diffusion-controlled in situ synthesis methodology is reported to achieve electrochromic nanofibrous membranes with mimetic chameleon skin structures (CSENs) by assembling electrochromic covalent organic frameworks (ECOFs) on nanofibers. CSENs exhibit reversible color changes in the visible and near- infrared ranges under an applied potential with fast response times (25.8 s/26.2 s). The macro- and mesoporous structures in CSENs favored the transportation of electrolyte ions, achieving excellent color difference and coloration efficiency of 35.58 and 1053.26 cm²/C, respectively.
To improve the growth rate of ECOFs on the fibers thus benefiting the electrochromic performance, we reported a facile methodology for fabricating an electrochromic microfibrous membrane (ECFM) with a biomimetic porous architecture via bidirectional diffusion-controlled in situ synthesis of ECOFs on intrinsically porous microfibers. The resultant ECFM features coral-like hierarchical pores, including micrometer pores formed by fiber entanglement, sub-micrometer pores in the porous microfibers, and intrinsic mesopores of the ECOFs, which facilitate the transportation efficiency of electrolyte ions. Thus, the ECFM demonstrates reversible switching between yellow and black under applied voltage, with fast response times (coloration/bleaching=13.6 s/17.8 s), remarkable color contrast (ΔE=25.7), and superior coloration efficiency (154.66 cm²/C).
However, the low conduction efficiency of electrons at the interface of an EC fabric with “sandwich” structure generally results in poor EC performances. Herein, we further reported a strategy of constructing EC covalent organic framework-aerogel textiles (ECATs) with ternary-nested electron transport channel that inspired by biological neural system. Carbon woven fabric provides a three-dimensional porous skeleton that enables long-range yet high-density pathways for electronic current flow. Within this skeleton, EC covalent organic framework (ECOF) particles and bacterial cellulose nanofibers self-assemble into a “bead-on-string” aerogel network, which achieves a saltatory conduction of electrons and a low-resistance channel for electrolyte ions. Importantly, dual-donor ECOFs are first synthesized to regulate the electron transport by boosting carrier persistence and charge utilization at the molecular level. Given the precisely engineered architecture of ECATs, they exhibit rapid and robust EC responses (~10 s, 100 cycles), multicolor tunability, record-high coloration efficiency (543 cm²/C), and excellent breathability and flexibility. ECATs further display exceptional damage tolerance without sacrificing their superior EC performances, thus ensuring long-term stability and practical reliability.
The above works successfully developed three types of electrochromic materials with excellent flexibility, breathability, and mechanical strength, highlighting their strong potential as smart textile materials for dynamic camouflage stealth. They would also inspire broad applications of such materials for wearable display and dynamic sensing.

Electrochromic,covalent organic framework,texitle,camouflage