Low-temperature green synthesis of few-layered graphene sheets from pomegranate peels for supercapacitor applications

Abstract

Graphene presents practical applications in energy storage devices, especially supercapacitors. However, mainstream synthesis of graphene includes toxic chemical usage, which threatens the environment. With the recent attention shift to synthesizing nanomaterials from agro-waste due to their easy availability, cost-effectiveness, and, most importantly, their environmental friendliness, we present, in this work for the first time, a novel and green synthesis of few-layered graphene sheets using pomegranate peels as a precursor at a low temperature of 80 °C. The surface morphology and microstructural properties are determined by Transmission Electron Microscopy (TEM), Energy Dispersive X-Ray spectroscopy (EDX), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), UV–visible spectroscopy (UV–vis), and the electrical properties determined by Hall Effect Measurement. The application as a supercapacitor is also examined using Cyclic Voltammetry (CV), Charge–Discharge Cycling (GCD), and Electrochemical Impedance Spectroscopy (EIS). The resulting supercapacitor delivers an areal capacitance of $$3.39 mF{cm}^{-2}$$ 3.39 m F cm - 2 at a current density of 15.6 μA $${cm}^{-2}$$ cm - 2 , making our synthesized graphene a good choice for electrochemical storage devices.

Graphene-Infused Hybrid Biobattery–Supercapacitor Powered by Wastewater for Sustainable Energy Innovation

“…Notably, graphene's barrier properties play a vital role in enhancing the corrosion resistance of metal-based electrodes, offering applications in biotic and abiotic applications [14][15][16]. While conventional graphene synthesis methods involve chemicals that are highly corrosive, explosive, and toxic [17,18], the plasma exfoliation process employed in this study stands out for its ability to synthesize graphene without such precursors. This process utilizes a dielectric barrier discharge plasma system under near-ambient conditions, showcasing a sustainable approach to graphene production.…”

High-capacity vanadium nitride anode materials synthesized by melamine-assisted pyrolysis

“…For supercapacitors, the electrode materials are mostly carbon-based. These include 0D quantum dots 6,7 and carbon dots, 8,9 1D nanowires 10 and carbon nanotubes, 11,12 2D graphene 13–15 and MXene, 16–18 and 3D metal–organic frameworks, 19–22 such as metal sulfides (CoS), metal oxides (RuO 2 , 23,24 V 2 O 5 , 25–29 and Co 3 O 4 30,31 ), conductive polymers (PANI, 32–34 PPY, 34,35 and PTh 36,37 ), and transition metal nitrides (VN 38,39 and MoN 36,40 ). Vanadium nitride 41 (VN) is the earliest metal nitride to be employed as the pseudocapacitive electrode material, and has the advantages of exceptional theoretical specific capacity (1, 340 F g −1 ), superior conductivity (1.6 × 10 6 S m −1 ), and a voltage window of 1.2 V in an alkaline electrolyte.…”

Mild and Efficient One-Step Synthesis of Nitrogen-Doped Multistage Porous Carbon for High-Performance Supercapacitors

“…As is universally acknowledged, carbon-based materials are extensively employed as the electrode material in electric double-layer capacitors (EDLCs), owing to their costeffectiveness, generally high specific surface area, and excellent chemical stability. Nanotextured carbon materials such as graphene [6,7], mesoporous carbon [8,9], carbon nanotubes [10,11], and carbon aerogel [12,13] have been shown to have excellent capacitive properties. However, intricate manufacturing methods and elevated costs hinder their applications.…”

“…However, intricate manufacturing methods and elevated costs hinder their applications. In recent years, some works on graphene-based materials low-cost and easily scalable synthesis have been reported [9,14,15], but their capacitive properties need to be enhanced. Commercial activated carbons are still the most common electrode materials today; unfortunately, they are mainly obtained from fossil fuels, and the precursors are environmentally unfriendly and expensive.…”