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

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(<i>para</i>-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 CC, C-H, and CC 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.