Pseudocapacitive efficiency of covalently Cr-complex with L-histidine-methyl ester as a ligand graphene oxide blended with conducting polymer (POAP) as electrode material in supercapacitor

The structure of electrode materials is still a critical challenge to improve the electrochemical features toward widespread application of supercapacitors. Functionalized graphene oxide and their derivatives or composites can synergically increase the electrochemical performance. In this work we synthesized graphene oxide (GO) through Hummer's method and then GO was functionalized by L-histidine-methyl ester dihydrochloride (LHMEC) in the presence of an ionic liquid (1-buthyl-3-methyl-imidazolium bromide). The obtained product was further reacted with triethyl amine (Et3N) and CrCl3 to host a Cr-containing molecule grafted covalently on the GO surface (Cr-GO). The fractal concept showed a porous structure based on log-log scale plotting of potential at current density. Additionally, the Cr-GO composited electro-synthetically with poly ortho amino phenol (POAP) as a conductive polymer, and then employed as an efficient porous electrode material in a two-electrode setting (Cr-GO-POAP). The employed Cr-GO-POAP improved the supercapacitive behavior with enhancing conductivity and facilitating electron movements in electrolyte with specific capacitance of 354 F g(-1) at 0.5 A g(-1) and obvious wider CV curves. Cyclic voltammetry and EIS techniques showed high-efficient performance in electron conducting with excellent durability and cycle life (similar to 94%) after 5000 cycles. Both energy and power densities were improved by 12.29 W h kg(-1) and 250 W kg(-1), respectively. (C) 2020 Elsevier B.V. All rights reserved.