Activated carbons prepared from hazelnut shell waste by phosphoric acid activation for supercapacitor electrode applications and comprehensive electrochemical analysis
By Ozpinar, Pelin; Dogan, Ceren; Demiral, Hakan; Morali, Ugur; Erol, Salim; Samdan, Canan; Yildiz, Derya; Demiral, Ilknur
Published in Renewable Energy
2022
Abstract
In this study, the activated carbon was produced from hazelnut-shell wastes using a single-step chemical activation. The activated carbon with a specific surface area of 1363 m2 g−1 and micropore volume of 0.52 cm3 g−1 was used to synthesize magnetic activated carbon to investigate the influence of the magnetization on the capacitive performance. The porous carbon samples were characterized using various techniques and analyses including N2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, Raman, and vibrating sample magnetometer. The prepared electrodes were evaluated by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The specific capacitance values of the activated carbon electrode and magnetic-activated carbon electrode were 247.8 F g−1 and 76.23 F g−1 at 0.75 A g−1, respectively. Moreover, the impedance responses were mathematically modeled using an equivalent electric circuit. Although a more homogeneous current distribution was obtained for the magnetic activated carbon, the higher constant phase element coefficient of the activated carbon demonstrated a higher capability of adsorption of mobile ions. The results showed the higher capacitive performance of the activated carbon electrodes for energy applications.