Nanostructured polyaniline/kenaf-derived 3D porous carbon materials with high cycle stability for supercapacitor electrodes

Kenaf-derived porous carbon (KPC) is considered to be one of the most promising materials for applications of energy storage devices due to being eco-friendly, and low cost. In this work, a facile method was introduced to prepare the nano-textured polyaniline (PANi)-decorated KPCs (PANi/KPC). Such light weighted and porous structures of KPCs were utilized as a physical framework for supporting the nanostructured PANi, which could significantly reduce the weight (and consequently cost) and furthermore improve the electrochemical performances of the supercapacitors. Firstly, we carbonized two different kinds of kenafs (kenaf stem and NaOH retting kenaf) to obtain the kenaf-derived porous carbons (KPC1 and KPC2), and then PANi was synthesized by in situ polymerization in the presence of KPCs. The three-dimensional porous structures of the obtained KPCs were confirmed by SEM images. The SEM image of PANi-decorated KPCs (PANi/KPCs) demonstrates that the PANi was uniformly formed as fibrous and nano-textured structures on the surface of the KPCs. The specific capacitance of PANi/KPC1 and PANi/KPC2 were found to be around 76 and 136 F/g, which were obviously enhanced capacitance than pure KPC1 (26 F/g) and KPC2 (37 F/g), respectively. Further, it showed good cycle stability retaining more than 97 % of their capacitance after 2000 charge–discharge cycles at a scan rate of 5 mV/s.