Superior pseudocapacitive performance of a nanocomposite of graphdiyne nanoflakes decorated with poly(4-chloroaniline)

Abstract

To enhance energy production and storage through cost-effective and less hazardous means in energy storage systems, particularly electrochemical pseudocapacitors, a two-dimensional carbon nanomaterial of graphdiyne (GDY) is utilized. A nanocomposite comprising segments of GDY nanoflakes combined with a conductive poly(para-chloroaniline) polymer was synthesized. Both the GDY nanoflakes and the nanocomposite were synthesized electrochemically and characterized. The nanocomposite synthesized at neutral pH included wrinkled sheets of 0.34 ± 0.07 μm² area and 17 ± 5 nm thickness with a uniform polymer layer coating the surface of GDY nanoflakes. However, some impurities originated from the synthesis precursors. Both the GDY nanoflakes and the nanocomposite represented signatures of the CC, C–H, and CC bonds of benzene rings, indicating the presence of a two-dimensional structure with sp–sp² carbon links having characteristic hexagons of a graphene structure with diynyl links having a well-developed network. At a current density of 25 mA g⁻¹, the nanocomposite represented a specific capacitance of 546 F g⁻¹, a specific capacity of 500 C g⁻¹, and an energy density of 127.1 W h kg⁻¹. At a current density of 0.25 A g⁻¹, the nanocomposite also maintained ∼98% of the initial capacitance over 5000 charge–discharge cycles. Electrochemical impedance spectroscopy revealed that the nanocomposite represented signatures of a redox reaction(s) and a finite length diffusion process, followed by charge accumulation at the nanocomposite/electrolyte interface. The findings confirm that the nanocomposite has great potential for application as a pseudocapacitor electrode material.