Cyperus pangorei porous carbon electrodes for the sustainable symmetric supercapacitor application

Efficiently addressing natural biowaste has the potential to effectively mitigate pressing environmental concerns. Given the growing demand for energy, it is imperative to identify a safe and environmentally friendly method for producing biowaste-based porous carbon (PC). Biowaste serves valuable carbon sources for the cost-effective production of efficient PC materials. In this study, we focus on ongoing research aimed at converting a small-scale industrial waste of Cyperus pangorei, into PC. To achieve this, we employed a simple and eco-friendly approach, optimizing the process at four different temperatures to enhance its suitability for supercapacitor applications. By subjecting the Cyperus pangorei waste to a two-step chemical activation process using potassium hydroxide (KOH) at 800 degrees C (referred to as CPC8), we obtained a PCs with a well-defined pore matrix, exhibiting a surface area of 711.2 m(2)g(-1). The resulting PC exhibited 194.6 Fg(-1) (0.5 Ag-1) of specific capacitance when tested in a 1 M Na2SO4 aqueous electrolyte. The galvanostatic study demonstrated remarkable 88.5 Whkg(-1) of energy density at 1.7 kWkg(-1) power density, along with a capacitance retention rate of 97.9% at 5000th cycle (8 Ag-1). Furthermore, electrochemical impedance study revealed 0.053 Omega of internal resistance, indicating enhanced ionic diffusion. Based on the excellent performance characteristics exhibited by CPC8, its practical application in supercapacitors holds great promise.