Processable nanoarchitectonics of two-dimensional metallo-supramolecular polymer for electrochromic energy storage devices with high coloration efficiency and stability

Two-dimensional porous metallo-supramolecular polymers (MSPs) have shown promising prospects for electrochemical-controlled functional devices as their highly reversible metal-centered redox chemistry. However, parallel efforts to solution-processable large-area uniform film based on high-quality MSPs have encountered with limited success. Herein, we develop a scalable method for synthesizing MSP-Fe with “gram” scale by coordinating 1,3,5-tris(4-(2,2′:6′,2″-terpyridyl)phenyl)benzene with Fe(II) ions. The uniform MSP-Fe film is assembled on a transparent conductive substrate by electrostatic spray technology. The obtained MSP-Fe films exhibit excellent electrochromic performance and energy storage property simultaneously, such as ultrahigh coloration efficiency of 1103.9 ( ± 100) cm² C⁻¹, fast switching speed (< 1.5 s), large optical contrast (> 71.7%), and high specific capacity (12.01 mAh g⁻¹). More importantly, the degradation of optical contrast is only 3% after 10,000 cycles, proving the remarkable cycle stability of the MSP-Fe film. We further demonstrate a smart energy-storage indicator assembled by the MSP-Fe films, in which the energy-storage level is visually perceptible and recognizable in real-time. Furthermore, a large-area semi-solid-state electrochromic device (225 cm²) is successfully constructed based on MSP-Fe films, which achieves a uniform, fast, and reversible color variation across the device.