A novel ferrocene-containing aniline copolymer: its synthesis and electrochemical performance

A novel ferrocene-containing aniline, 6-(2-amino-phenol-9H-yl)-hexyl ferrocenecarboxylate (AnFc) was synthesized via the hydrogenation of 6-(2-nitro-phenol-9H-yl)-hexyl ferrocenecarboxylate (NPFc). Then, the homopolymer of AnFc (PAnFc), copolymers of aniline and AnFc (P(An-co-AnFc)), and polyaniline (PAn) were prepared using a chemical oxidative polymerization process. The structure, morphology, and electrochemical properties of the prepared polymers were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV-vis), scanning electron microscopy (SEM), cyclic voltammograms (CV) and galvanostatic charge-discharge tests. The results demonstrated that the AnFc functionalized monomer and the corresponding polymer derivatives have been synthesized successfully, and the introduction of the novel functionalized ferrocene-based aniline obviously affected the spectral characteristic, morphology and electrochemical characteristics of the electro-active polymers obtained, as well as its charge migration along the polymer backbone. In addition, the charge-discharge tests showed that P(An-co-AnFc) improved the discharge plateau in the potential range of about 3.0-4.0 V and with an acceptable initial discharge specific capacity of 104.9 mA h g(-1) for P(An-co-AnFc) (5 : 1 ([An]/[AnFc])) (compared with 108.2 mA h g(-1) for PAn). Furthermore, P(An-co-AnFc) exhibited an even more improved cycling stability than that of PAn, and after 30 cycles the discharge capacity of P(An-co-AnFc) (3 : 1 ([An]/[AnFc])) still maintained 76.3% of the capacity obtained during the initial cycle.