Comparative Analysis of Cellulosic Supercapacitors from Waste Paper Sources for Energy Storage Applications

Abstract

Energy storage devices are in demand due to the rise of portable electronics. Polymers are better substitutes for electrode and electrolyte materials as they can withstand mechanical deformations. Waste paper, an inexpensive lignocellulosic biomass, can act as a cellulosic source. This study compares the efficiency of supercapacitors composed of cellulose from waste office paper (OMCC), newspaper (NMCC), and corrugated boxes (CMCC) using chemical treatment. The supercapacitor nanocomposite was made by depositing rGO/ZnO nanowires on cellulose using hydrothermal treatment and press strategies. The SEM showed uniform deposition of rGO/ZnO over cellulose crystals, while EDX confirmed ZnO presence on the cellulose surface. XRD peaks corresponding to rGO and ZnO were observed confirming their presence on the cellulose. Electrochemical impedance spectrometry, galvanic charge-discharge, and cyclic voltammetry were performed. At scan rates below 20 mV/s, all three electrodes functioned effectively in cyclic voltammetry. The NMCC nanocomposite has the highest specific capacitance of 3.607x105 F/g followed by CMCC and OMCC at 1.68x105 F/g and 3.6x104 F/g respectively. Additionally, the current density of NCC nanocomposite was highest (6.14x105 J/m3) in comparison to CMCC nanocomposite (3.35x105 J/m3) and OMCC nanocomposite (7.2x104 J/m3). This biodegradable and cost-effective cellulose/rGO/ZnO supercapacitor can be used in any portable energy storage device.