Tetranitro-substituted cobalt phthalocyanine immobilized on reduced graphene oxide as supercapacitor electrode material with enhanced capacitance

Recent progress in the construction of metal phthalocyanines (MPcs) has opened up new strategies for energy storage applications. Since MPcs possess excellent redox activities, we have developed a simple ultrasound process to fabricate nanocomposites based on different ratios of tetranitro-substituted cobalt phthalocyanine (Co(NO2)4Pc) and reduced graphene oxide (rGO) and evaluated their energy storage performance for supercapacitor. A maximum specific capacitance of 150.22 F g−1 was achieved for the Co(NO2)4Pc-rGO 1/6 electrode at high current density (4 A g−1), which is 1.6 and 1.8 times higher than the individual materials, respectively. This great electrochemical activity is attributed to the synergistic effect between two components. Moreover, this electrode manifested outstanding cycling stability (retained 111.6 % of its initial capacitance after 5000 cycles). The experimental findings ensure the potential application of Co(NO2)4Pc-rGO composite as an electrode material for the next-generation supercapacitor applications.