Cu-MOF-derived Cu2V2O7@C nanofilm for electrochromic properties.

Electrochromism (EC) is a color control technique for providing visual information, in which vanadium pentoxide (V₂O₅) is a promising material for electrochromic applications due to its excellent ionic intercalation/deintercalation properties and cathodic/anodic color-changing properties. However, its poor cycling stability and color change response rate limit its practical application. Metal–organic frameworks (MOFs) combine the rigidity and flexibility of inorganic–organic materials and can meet the requirements of EC materials such as cycle stability, electrical conductivity, and stress-interference resistance. We report here a strategy to modify V₂O₅ with Cu-MOF. Cu-doped V₂O₅ and carbon skeleton (Cu₂V₂O₇@C) composites were prepared for electrochromism. In this scheme, Cu doping can facilitate lithium ion migration by broadening and stabilizing the structure of V₂O₅, and the distribution of the carbon skeleton can broaden the contact of the active material with the electrolyte and improve the electron conduction. Combining these merits, it exhibits excellent long-term cycle stability (the capacity retention rate reaches 91.78% after 2000 cycles), the light transmission modulation is greatly improved compared with V₂O₅ (ΔT = 69%, doubled), and the response time is reduced by 30.43%. This study provides a new perspective for improving the light modulation ability and long-term use stability of vanadium oxide EC materials and promotes the development of MOF materials in the field of electrochromism. [ABSTRACT FROM AUTHOR]