Conjugated tetraphenylethene-based polymers for supercapacitor

Abstract

The synthesis of two conjugated polymers (P1 and P2) for supercapacitor application was reported. The materials were prepared using a condensation reaction between tetraphenylethene (TPE) with di-(TPE-2CHO) or tetra-carboxaldehyde (TPE-4CHO) derivatives and 1,5-diaminonaphthalene (1,5-DAN). The polymers were characterized using Fourier transforms infrared (FT-IR), solid-state ¹³C nuclear magnetic resonance (¹³C NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and diffuse reflectance spectroscopy (DRS). P1 and P2 polymers displayed a spherical shape, with particle sizes of 6.8 ± 1 μm and 0.97 ± 0.1 μm, respectively. In addition, P1 and P2 exhibited wide light absorption (200–466 nm), accompanied by a relatively low bandgap of 2.3 eV and 2.4 eV for P1 and P2 respectively. Electrochemical investigations of P1 and P2 revealed redox behavior observed in the cyclic voltammetry (CV) curves suggesting a faradaic charge storage mechanism. At a scan rate of 1 mV/s, P1 and P2 demonstrated specific capacitances of 274.8 F/g and 207.9 F/g, respectively. The electrochemical performance of both polymers was further analyzed using galvanostatic charge-discharge (GCD), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) using Nyquist plots. The observed decrease in charge transfer resistance for P1 and P2 can be ascribed to the conjugation within their chemical structures. The polymer can be recycled for 5000 cycles with <10 % loss of the polymer's efficiency.