Constituent material influence on the electrochemical performance and supercapacitance of PAni/diamond/CF composite

Highlights: • PAni/B-doped diamond/CF composites were produced and characterized. • Structurally different CF were used, heat treated at 1000 and 2000 °C. • Diamond films were grown on CF at different morphologies, micro and nanocrystalline. • PAni/BDD/CF2000 composite presented the best electrochemical performance. • The electrode showed specific capacitance of 526.5 F/g in 1 mol L⁻¹ H₂SO₄. - Abstract: Ternary composites of polyaniline (PAni)/diamond/carbon fiber (CF) were produced and characterized, evaluating the influence of the constituent materials. Different CF heat treatment temperatures were used, 1000 and 2000 °C, producing structurally different CF. In addition, diamond films were grown on CF at two different morphologies, boron doped nanocrystalline (BDND) and microcrystalline (BDD) diamond films. A NaCl/HCl solution with distilled aniline was used for PAni chemical synthesis. FEG-SEM images showed that both PAni and diamond coatings covered and enwrapped the fibers. Raman spectra exhibited the differences in the samples structure. Among the studied ternary composites, electrochemical results indicated that the PAni/BDD/CF2000 composite has the highest capacitance response and charge storage capacity, the most reversible oxidation and reduction processes, and the lowest charge transfer resistance, presenting specific capacitance of 526.5 F/g. Moreover, this work confirmed that the structure and morphology of the constituent materials affected the electrochemical performance of the ternary composite.