From electrode to device characterizations of polyaniline/micro and nanodiamond/carbon fiber as ternary composites applied as supercapacitor

Abstract

Production and characterization of polyaniline/boron-doped diamond/carbon fiber (PAni/diamond/CF) ternary composites are presented in this work, as well as the application as electrode for a supercapacitor device. Different diamond morphologies were evaluated, boron-doped nano- and microcrystalline diamond (BDND/BDD). PAni was chemically synthetized in different deposition times, from 10 to 60 min. FEG-SEM images showed differences on PAni deposition for each condition. Raman and FTIR analyses confirmed PAni formation as its conductive form. TGA analyses exhibited the samples’ thermal behaviors. Through electrochemical characterizations, PAni deposition time and diamond influence were studied. Diamond films improved PAni deposition and enhanced electrochemical reversibility, especially BDD. For the 10-min deposition, diamond influence was better observed, and the composites showed to be reversible even at high scan rates. However, for 60 min, the electrodes presented a much higher charge storage capacity. Therefore, BDD film with 60 min of PAni deposition proved to be the best combination, in which the composite presented a specific capacitance of 520 F g−1 in 1 mol L−1 H2SO4. Thus, this electrode was used for the supercapacitor device assembly, exhibiting high capacitive behavior, 99% of coulombic efficiency, 83% of capacitance retention after 1000 cycles, and a tendency to stabilize capacitance along the number of cycles.