Polyvinylidene Fluoride-Based Carbon Supercapacitors: Notable Capacitive Improvement of Nanoporous Carbon by the Redox Additive Electrolyte of 4-(4-Nitrophenylazo)-1-naphthol

Abstract

The nanoporous graphitic carbon materials (NGCM) have been prepared by a synchronous carbonization and graphitization process, using waste polyvinylidene fluoride (PVDF) as carbon precursor and Ni(NO3)2·6H2O as the graphitic catalyst. It reveals that the carbonization temperature plays a crucial role in determining the pore structures as well as their electrochemical performances. Increasing the carbonization temperature from 800 to 1200 °C, the corresponding porosity has slightly decreased, accompanied by an increase of graphitization degree. Next, to further improve the electrochemical performance of the sample prepared at 800 °C, a novel redox additive of 4-(4-nitrophenylazo)-1-naphthol (NPN) with different amounts has been introduced in 2 mol L–1 KOH electrolyte. Therein, the specific capacitance by adding 4 mmol L–1 of NPN can reach 2.98 times higher than the pristine value. Apparently, the mixed electrolytes have largely enhanced the electrochemical performance, which is expected to be applied in th...