Facile Synthesis of Pineapple Waste-Derived Carbon and Polyaniline Composite for High-Energy-Density Asymmetric Supercapacitors

Pineapplepeel has been chosen as a biowaste precursor to synthesizeactivated carbon via KOH activation at 800 degrees C(PP-800). Further, the in situ chemical oxidationmethod was used to synthesize a composite of PP-800 with polyaniline(PANI). The successful formation of the composite (PP-800/PANI) wasconfirmed via X-ray diffraction (XRD), and Ramanand Fourier-transform infrared (FTIR) spectra. PP-800/PANI when testedin 1 M H2SO4 in a three-electrode configurationshowed a higher specific capacitance (377 F/g) than that of PP-800(328 F/g) and PANI (92.4 F/g) at 2 A/g. This is due to the significantenhancement in the diffusion contribution for PP-800/PANI (86.25%)than that of PP-800 (61.7%) and PANI (49.9%) counterparts at 20 mV/s,which leads to the maximum utilization of the electrochemical surfacearea. Further, an asymmetrical supercapacitor device, PP-800/PANI//PP-800,was fabricated, which delivered a high energy density of 51.2 Wh/kgat a decent power density of 380 W/kg with 90% cyclic stability after10,000 charge-discharge cycles.