ABASTRAT: In the present work, a self-standing conductive polyaniline/polyvinyl alcohol (PANI/PVA) hydrogel (CPHPA/SA) co-doped with phytic acid (PA) and sulfuric acid (SA) was synthesized by chemical oxidation polymerization. The anisotropic tubular structure imparted by SA and the three-dimensional microporous structure imparted by PA enable CPHPA/SA electrodes to exhibit excellent mechanical and electrochemical performances. The CPHPA/SA electrodes showed high areal specific capacitance of 1697 mF/cm2 at current density of 1 mA/cm2 and outstanding cycling stability of 83% capacitance retention after 10000 charge/discharge cycles at current density of 3 mA/cm2, which was superior than that of single-doping hydrogel electrode. In order to further explore the potential application prospects of the synthesized hydrogel electrodes in flexible devices, an all-hydrogel flexible supercapacitor device was fabricated by CPHPA/SA hydrogel electrodes and PVA/H2SO4 hydrogel electrolyte. The assembled supercapacitor exhibited high energy density of 52.2 µWh/cm2 at the power density of 250 µWh/cm2. A sensor was designed based on the CPHPA/SA hydrogel, which can detect the tiny signals related to human body with low distortion. This study provides a new direction for the preparation of novel energy storage and wearable smart sensors and human health monitoring devices with flexible hydrogel electrode materials.
Keywords: polyaniline, co-doping, supercapacitors, electrochemical properties, sensor.