Facile synthesis and characterization of Co3O4 nanoparticles for high-performance supercapacitors using Camellia sinensis

In this study, synthesis and characterization of cobalt oxide nanoparticles (Co3O4 NPs) using green tea leaf (Camellia sinensis) and its utilization as high-performance supercapacitors has been studied. Co3O4 NPs were fabricated utilizing aquatic extract of Camellia sinensis as a reduction agent, and it was annealed at various annealing temperatures, such as 200 °C, 400 °C, 600 °C, and 800 °C for 2 h. The synthesized Co3O4 NPs were analyzed using XRD, FESEM, EDX, HRTEM, PL, FTIR, UV–visible techniques. The higher concentration of phenolic compounds with antioxidant potential, amino acids, proteins and lipids in Camellia sinensis act as the reducing as well as the stabilizing agents for the growth of NPs. The XRD analysis confirms that the crystalline behavior of the annealed samples increases with increasing annealing temperature. The electrochemical performance of green synthesized nanostructured Co3O4 NPs shows an excellent supercapacitance performance with quick dispersing of electrolyte ions into the Co3O4 electrode owing to their rapid charging and discharging performances. This affirms that the bio-synthesized Co3O4 nanomaterial is the appropriate material for high performance supercapacitor applications.