Sweet-Lime-Peels-Derived Activated-Carbon-Based Electrode for Highly Efficient Supercapacitor and Flow-Through Water Desalination

摘要

In the present work,highly porous activated carbon with an excellent surface area has been successfully synthesized from the agricultural waste product;sweet lime peels(Citrus limetta)using a facile chemical approach.The structural and morphological properties of sweet lime peels derived activated carbon(SLP-AC)were studied using X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),and X-ray photoelectron spectroscopy(XPS).Brunauer-Emmett-Teller(BET)surface area and pore structure were studied using nitrogen adsorption-desorption isotherms.Electrochemical characterizations were performed in two and three electrode cell configurations using techniques like cyclic voltammetry(CV),Galvanostatic charge-discharge(GCD)and electrochemical impedance spectroscopy(EIS)in aqueous(1 M H2SO4 and 1 M NaCl)and ionic liquid electrolytes(EMIMBF4).SLP-AC based electrodes showed high electrochemical charge storage capacity of 421.67 F/g(at 1 A/g)along with outstanding cyclic stability up to 10000 GCD cycles.Fabricated supercapacitor device demonstrated high energy density of 45.53 Wh/kg in the ionic liquid electrolyte.SLP-AC was also used to prepare the porous sponge electrodes to study their applicability in flow-through electrode capacitive deionization(CDI),where it achieved the maximum electrosorption capacity of 22.8 mg/g.The electrosorption results fitted well with the Langmuir isotherm and the kinetics study indicates a pseudo-first-order kinetic model for the electrosorption of salt ions onto the electrodes surface.This confirms the outstanding performance of SLP-AC as a highly stable and low-cost electrode material for supercapacitors and water desalination applications.