Solution processable triarylamine-based polyamide for electrochromic supercapacitors and smart displays with energy reuse

Electrochromic (EC) materials based on ion insertion/desertion mechanisms provide a possibility for energy storage. Solution-processable energy storage EC polyamides have great potential for use in smart displays and EC supercapacitors. A suitable monomer structure design is particularly important for enhancing the electrochemical properties of polyamides. The symmetrical donor-acceptor-donor structure triarylamine (TAA) diamine monomer was prepared by the Ullmann reaction, and the corresponding polyamide (named BDPA-CA) was prepared by polycondensation reaction. The propeller-shaped skeleton of the TAA unit effectively increases the internal volume and endows the BDPA-CA with the property of solution processing. The introduction of electron-withdrawing benzothiadiazole groups into the main chain enhances the optical contrast of BDPA-CA during electrochemical oxidation. Moreover, the energy storage mechanism of BDPA-CA is elucidated via density functional theory calculations. The exposed sulfur (S) and oxygen (O) atoms in BDPA-CA can serve as active sites for lithium ion (Li+) binding, and the nitrogen (N) atom at the center of the TAA moiety is a perchlorateion (ClO4-) binding active site, which suggests that the full interaction of the dual active sites can increase the capacitance value of the BDPA-CA film electrodes.