Self-crosslinked polyaniline hydrogel electrodes for electrochemical energy storage

Polyaniline (PAni) hydrogels, the combination of the conducting polymers and hydrogels, might have possessed widespread application potentials in the fields of such as electrochemical energy storage, metal corrosion resistance, biological and chemical sensor, etc. Self-crosslinked PAni hydrogels have been synthesized via oxidative coupling reaction in the absence of any additional crosslinkers by using ammonium persulfate as the oxidizing agent and aniline hydrochloric salt as the precursor. The molecular structure of the resulting PAni hydrogels have been confirmed by Fourier-transform Infrared (FTIR) spectroscopy, Raman spectroscopy and X-ray diffraction (XRD), the morphology and porous structure of the resulting hydrogels have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen sorption test, and the mechanical properties of the resulting PAni hydrogels have been investigated by dynamic rheological measurements and compressive stress–strain measurements. The electrochemical properties have also been revealed in detail and the results have indicated that the as-prepared PAni hydrogel electrodes have a maximum specific capacitance of ∼750 F/g at a current density of 1 A/g. The scalable synthesis as well as superior electrochemical performances makes the resulting PAni hydrogel a promising material for energy storage.