Biopolymer phytagel-derived porous nanocarbon as efficient electrode material for high-performance symmetric solid-state supercapacitors

In the present work, a porous nano-carbon (PNC) based electrode materials were successfully derived from the natural biopolymer phytagel via a facile hydrothermal and combustion process. The carbon phase structure of the PNC electrode was confirmed using different spectroscopy, microscopy and N₂ adsorption-desorption analyses. The surface morphology investigation showed a distinct shape and size for the PNC that demonstrated its porous nature. The electrochemical performance of PNC was completely reliant on the calcination temperature (800 °C) and it delivered the maximum capacitance of 122 F g⁻¹ at 0.25 Ag⁻¹. An AC impedance and cyclic voltammetry analyses proved the intrinsic electrochemical behavior by their cycling. Besides, the fabricated symmetric solid-state supercapacitor displayed an outstanding cycle durability with a stable capacitance retention of 85.8% over 8000 cycles, suggesting favorable prospects for its use as an active candidate for symmetric solid-state supercapacitor applications.