Electrochemical Double Layer Capacitors Research Articles

Li-metal free “in aqua” lithiation and re-lithiation of protected graphite anode for 4-V class aqueous lithium-ion capacitor

Lithium-ion capacitors, typically composed of a capacitive cathode and a pre-lithiated graphite anode in non-aqueous electrolyte, are promising power sources for energy harvesting applications with higher energy densities than standard electrochemical double layer capacitors. Superior energy density can be achieved by using pseudocapacitive cathodes in an aqueous electrolyte coupled with a water-stable protected anode. Lithiation of the graphite anode is one of the performance-governing processes influencing the working voltage, energy density, and cyclability of such power sources. Here, we report an effective, time-efficient, and safe lithiation procedure without the need of lithium metal or lithium-containing compounds as electrodes. The “in aqua” electrochemical lithiation of graphite is performed by using an over-sized activated carbon cathode and the salt dissolved in the aqueous electrolyte as the source of lithium ions. Subsequently, the protected anode (LixC6 + Li) is used as the counter electrode in an aqueous hybrid supercapacitor showing ∼70 % of capacity retention after 10,000 cycles. Nonetheless, the cycle life and capacity retention of the protected anode was further extended via an “in aqua” re-lithiation process allowing a 95 % retention of the initial capacity after 10,000 galvanostatic charge/discharge cycles.

Enhancing stability in Acetonitrile-Based Supercapacitors: Implementation of Di-Pyrrolidinium ionic salts

One of the main strategies to enhance the energy density of electrochemical double layer capacitors (EDLCs) is to surpass the limitations of traditional electrolyte operating voltages. In our study, a novel high-purity di-pyrrolidine based electrolyte salt, 1-butyl-3-dimethylpyrrolidinium di[bis(trifluoromethanesulfonyl)imide] (C4di[mPyr].di[TFSI]) is synthesized, and high voltage electrolyte using acetonitrile (AN) as the sole solvent is prepared for EDLCs. The 0.5 M C4di[mPyr].di[TFSI]/AN electrolyte demonstrates an impressive electrochemical stability window of 6.04 V and a high operating voltage of 3.4 V, which is almost the highest stability reported so far for low concentration AN-based electrolytes. The impedance and conductivity of the 0.5 M C4di[mPyr].di[TFSI]/AN electrolyte are highly comparable to commercial 1.0 M TEA.BF4/AN electrolyte. EDLCs equipped with the electrolyte can maintain specific capacitance retentions of 94.92 % and 77.78 % after 2000 cycles at 3.4 V and 3.6 V, respectively. Besides, the GC–MS and XPS further prove its stability and confirm the possible electrochemical reactions of the C4di[mPyr].di[TFSI]/AN electrolyte on the electrode surface under the polarized voltages. Furthermore, the XPS also appears to show a relatively weak interaction between TFSI− and the electrode, which may serve as a potential factor in inhibiting the hydrolysis of TFSI− and the polymerization of AN.

A review of EDLC and pseudocapacitance with synergistic integration of carbon-based and metal oxide materials for enhanced electrochemical energy storage

This paper provides a comprehensive analysis of the recent advancements in electrochemical double-layer capacitors (EDLCs) and pseudocapacitance, emphasizing the pivotal role of carbon-based materials, metal oxides, conducting polymers, and composites in augmenting the energy storage landscape. Through a systematic collection of electrochemical performance metrics, we elucidate the inherent advantages of these materials, such as superior electrical conductivity, enhanced surface area, and chemical robustness, which are instrumental in the development of next-generation supercapacitors. We discuss the integration of novel materials like reduced graphene oxide/hexagonal boron nitride composites, carbon onions, and various metal oxides that contribute to a significant increase in energy density and cycling stability. This work also highlights innovative fabrication techniques and synthesis methodologies that have resulted in electrodes with remarkable performance enhancements. Furthermore, the exploration of synergistic effects between different materials has led to hybrid structures that exhibit improved capacitive properties and operational efficiency.

Activated carbon synthesized from Jack wood biochar for high performing biomass derived composite double layer supercapacitors

In this study, the electrochemical properties of bioderived activated carbon-based electrodes for supercapacitors formed using a sintered ceramic binder were investigated. Activated carbon derived from Jack wood tree (Artocarpus heterophyllus) with variable amounts of TiO2 nanoparticles as a binder, were used as electrodes in order to get good, activated carbon films on FTO substrates. No other binders were used in this study since most conventional binders devastate the electrical conductivity in the films. Furthermore, TiO2 has higher temperature tolerance compared to polymeric binders thus the electrode prepared can be used in wider applications. A series of electrochemical double-layer capacitors were fabricated and characterized by cyclic voltammetry and galvanostatic charge-discharge measurements. The supercapacitors prepared showed double-layer capacitive behavior. The electrodes that contain 90 % activated carbon and 10 % TiO2 show optimum performance along with an impressive specific capacitance of 147 F g−1 at 2 mV s−1 scan rate. This supercapacitor exhibits a power density of 68.5 W kg−1 while the energy density is 8.02 Wh kg−1. When the power density is as high as 1186.51 W kg−1 the energy density drops to 5.71 Wh kg−1. According to cyclic voltammetry measurements taken for 1000 cycles, the supercapacitor shows excellent cycle stability without any traces of capacitance drop.

Advancing supercapacitor performance: a comprehensive review of electrochemical conversion of coconut shells into activated carbon nanofibers

This assessment provides a comprehensive evaluation of the limitations associated with the application of supercapacitors, along with the imperative to enhance their functionality. Following this, the advantages of Electrochemical Double Layer Capacitors (EDLC) are discussed in comparison to other types utilized in supercapacitor contexts. The transformation of coconut shells into carbon nanofibers is extensively investigated through various methodologies, highlighting both their benefits and limitations. It becomes evident that the current utilization of coconut shells has not yet achieved optimal sustainability or viability for energy storage purposes. Nevertheless, coconut shells offer a widely available and sustainable resource that can be converted into Activated Carbon nanofibers for energy storage applications. Diverse techniques have been employed to produce these ACB nanofibers, each targeting specific objectives including improved energy density, adaptable diameter, reduced energy consumption, and faster charging times. Despite these accomplishments, it is evident that numerous significant properties of carbon nanofibers derived from coconut shells remain unexplored, leading to substantial knowledge gaps that must be addressed for each technique. Therefore, further research is warranted to advance the comprehension of key parameters associated with various methods, ultimately facilitating the development of highly desirable carbon nanofibers sourced from coconut shells and catering to the requirements of sustainable energy storage applications.

Optimizing EMIMBF4-based electrolyte with LiBr redox medium for enhanced supercapacitors

The formidable challenge of supercapacitors (SCs) is to achieve both high energy density and high power density simultaneously. Although the utilization of porous carbon materials for physical adsorption in electrochemical double-layer capacitors (EDLCs) applications exhibits promising prospects, attaining exceptional performance necessitates additional methodologies. Here, we propose an effective strategy for formulating redox electrolytes through the incorporation of organic solvents and LiBr into 1-ethyl-3-methylimidazole tetrafluoroborate (EMIMBF4) electrolytes. Within this formulation, LiBr serves as a redox mediator, contributing Br−/Br3− redox pairs to the system. The incorporation of EMIMBF4-LiBr-DMSO in brominated redox EDLCs led to a significant enhancement in specific capacitance, reaching up to 39.72 F g−1, representing a remarkable increase of 159 % compared to EDLCs without any redox media. This configuration achieved a high power density of 496.6 W kg−1 while maintaining an energy density of 34.48 Wh kg−1.

In-situ synthesis of carbon-coated Mo2C: An exceptionally efficient and robust electrocatalyst for hydrogen evolution reaction (HER)

In the present work, the Mo2C electrocatalyst has been synthesized using waste plastic as carbon source. The use of plastic bottle has been chosen to reduce the cost of electrocatalyst as well to address the environmental issues caused due to these wastes. The pure phase sample was synthesized at 800 °C by carburizing MoO3 in an autoclave. The synthesized sample shows high activity towards HER with a lower Tafel slope of 85.7 mVdec−1. One of the exceptional features of the developed electrocatalyst is the long-term stability up to 7 days as determined by chronopotentiometry results. The improved activity and stability have been attributed to the presence of graphene like structures encapsulating the Mo2C particles. The presence of carbon also shows higher storage ability with an electrochemical double layer capacitance (EDLC, Cdl) of 91.0 μF. The synthesized sample shows an efficient and stable electrocatalyst towards HER.

Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

AbstractElectrochemical energy storage devices are built upon the foudations of batteries and supercapacitors. In the past decade, new pseudocapacitor‐like electrodes are intensively developed to obtain superior energy storage performance. Pseudocapacitive matarials store charge through Faradaic processes, while the electrochemical signal remains like electrochemical double‐layer capacitors (EDLCs). To address this controversy, an analytical model is introduced for evaluating the voltammograms of electrode materials. Given this, the work focuses on understanding the origin of the pseudocapacitive phenomena in the cyclic voltammetry (CV) electrochemical signal. Based on electron transfer mechanism and tunnelling effect within the atomic structure, pseudocapacitive matarials possess a high electron delocalization possibility related to the redox centers number and initiates the electrochemical potential distribution among neighboring redox sites, which is consequently observed in the electrochemical signal as the plateau feature in CV, like EDLC. First, the determination of the capacitive tendency of various electrode materials is proposed, which turns out to be relative to the redox centers number (n) and total charge (Z). Here, when this number is large, electron hopping will very likely happen. The developed model is versatile to predict rate/potential regimes for the maximum faradaic storage, and then well differentiates the pseudocapacitive and battery materials.

Production and characterization of activated carbon foams with various activation agents for electrochemical double layer capacitors (EDLCs) applications

Sucrose-based activated carbons were obtained by carbon foams with sugar and cobalt (II) nitrate as precursors, followed by using different chemical activation agents. The effect of Co(NO3)2 concentration, the carbonization temperature and the activation agent on the surface chemistry, porosity were investigated. Textural characterization and electrochemical tests were performed on the activated carbon samples (CF). The results showed that the activated carbon produced by H2SO4 and KOH at 800°C had a surface area of 691 m2/g and 1125 m2/g, 89% and 80% of the sample pore structure was microporous, and specific capacitance of 8.4 F/g and 162.2 F/g at a constant current density of 250 mA/g, respectively. K2CO3-activated carbon had 918 m2/g surface area and 63% of the sample pore structure with microporous and 1.4 F/g specific capacitance, H3PO4-activated carbon and ZnCl2-activated carbon had 1833 m2/g and 1597 m2/g surface area, 53% mesoporous and 50% mesoporous, 222.4 F/g and 149.9 F/g specific capacitance respectively. The most promosing result was observed in the electrochemical storage behavior of the carbon materials with hierarchical pore structure activated with H3PO4 is associated with increasing defect zones at the edges of micro- and mesoporous morphology, resulting in a higher surface area and increased conductivity of the material.

A Review on Nano Fluid Production, Mathematical Modelling and Applications

Recently, nano fluids have taken on a significant role in many human endeavours. A fluid called a nanofluid includes nanoparticles, also called nanoparticles. Colloidal suspensions of nanoparticles in a base fluid are what these fluids are made of. The numerous production procedures and mathematical interpretation models for nanofluids are examined in this review study. Marangoni convection’s advantages, which enhance heat transfer and balance temperature distribution, are underlined. The effects of thermophoresis on surface tension as well as surface tension in laminar natural convection are also discussed in this work. The characteristics of carbon nanotubes and their prospective medical uses are covered in the article. The study covers electrochemical double layer capacitors, which offer greater safety, longer cycle stability, and better power densities. The study explores the impact of magnetic fields on entropy formation and natural convection in a hybrid nanofluid enclosure, revealing four distinct models based on thermal conductivity and viscosity correlations. The information review work is relevant. The review information work is relevant to flow tracers, prosthetic heart valves, oil pipelines, chemical industry separation methods, and oil recovery.

Interaction of electrolyte molecules with the surface of porous carbon: NMR study

Electrochemical double-layer capacitors use porous carbons as the electrode material, and improving their performance requires an understanding of the electrolyte−carbon surface interactions. 13C, 14N, and 11B NMR spectroscopy were used to investigate the behaviour of the electrolytes [C(OCH3)3NH3]+Cl- and [N(CH2CH3)]+BF4- on the surface of porous carbon in D2O solutions. A chemical shift of 13C has been found in the fragments N–C, indicating electron density redistribution between nitrogen atoms and alkyl fragments. The presence of a signal with a chemical shift of d = 7.7 confirms the structuring of the electrolytic layer of water solution [N(CH2CH3)]+BF4-.

Hydrogen-Assisted Thermal Treatment of Electrode Materials for Electrochemical Double-Layer Capacitors.

The capacitance of electrode materials used in electrochemical double-layer capacitors (EDLCs) is currently limited by several factors, including inaccessible isolated micropores in high-surface area carbons, the finite density of states resulting in a quantum capacitance in series to Helmholtz double-layer capacitance, and the presence of surface impurities, such as functional groups and adsorbed species. To unlock the full potential of EDLC active materials and corresponding electrodes, several post-production treatments are commonly proposed to improve their capacitance and, thus, the energy density of the corresponding devices. In this work, we report a systematic study of the effect of a prototypical treatment, namely H2-assisted thermal treatment, on the chemical, structural, and thermal properties of activated carbon and corresponding electrodes. By combining multiple characterization techniques, we clarify the actual origins of the improvement of the performance (e.g., > +35% energy density for the investigated power densities in the 0.5-45 kW kg-1 range) of the EDLCs based on treated electrodes compared to the case based on the pristine electrodes. Contrary to previous works supporting a questionable graphitization of the activated carbon at temperatures <1000 °C, we found that a "surface graphitization" of the activated carbon, detected by spectroscopic analysis, is mainly associated with the desorption of surface contaminants. The elimination of surface impurities, including adsorbed species, improves the surface capacitance of the activated carbon (CsurfAC) by +37.1 and +36.3% at specific currents of 1 and 10 A g-1, respectively. Despite the presence of slight densification of the activated carbon upon the thermal treatment, the latter still improves the cell gravimetric capacitance normalized on the mass of the activated carbon only (CgAC), e.g., + 28% at 1 A g-1. Besides, our holistic approach identifies the change in the active material and binder contents as a concomitant cause of the increase of cell gravimetric capacitance (Cg), accounting for the mass of all of the electrode materials measured for treated electrodes compared to pristine ones. Overall, this study provides new insights into the relationship between the modifications of the electrode materials induced by H2-assisted thermal treatments and the performance of the resulting EDLCs.

A rational study of transduction mechanisms of different materials for all solid contact-ISEs

The new era of solid contact ion selective electrodes (SC-ISEs) miniaturized design has received an extensive amount of concern. Because it eliminated the requirement for ongoing internal solution composition optimization and created a two-phase system with stronger detection limitations. Herein, the determination of venlafaxine HCl is based on a comparison study between different ion- to electron transduction materials (such as; multiwalled carbon nanotubes (MWCNTs), polyaniline (PANi), and ferrocene) and illustrating their mechanisms in their applied sensors. Their different electrochemical features (such as bulk resistance (Rb**), double-layer capacitance (Cdl), geometric capacitance (Cg), and specific capacitance (Cp)) were evaluated and discussed by using the Electrochemical Impedance Spectroscopy (EIS), Chronopotentiometry (CP), and Cyclic Voltammetry (CV) experiments. The results indicated that each transducer's influence on the proposed sensor's electrochemical characteristics is determined by their unique chemical and physical properties. The electrochemical features vary for different solid contact materials used in transduction mechanisms. The results confirm that the MWCNT sensor revealed the best electrochemical behavior with the potentiometric response of a near-Nernestian slope of 56.1 ± 0.8 mV/decade with detection limits of 3.8 × 10−6 mol/L (r2 = 0.999) and a low potential drift (∆E/∆t) of 34.6 µV/s. Also, the selectivity study was performed in the presence of different interfering species either in single or complex matrices. This demonstrates excellent selectivity, stability, conductivity, and reliability as a VEN-TPB ion pair sensor for accurately measuring VEN in its various formulations. The proposed method was compared to HPLC reported technique and confirmed no significant difference between them. So, the proposed sensors fulfill their solutions' demand features for VEN appraisal.

Cation desolvation-induced capacitance enhancement in reduced graphene oxide (rGO)

Understanding the local electrochemical processes is of key importance for efficient energy storage applications, including electrochemical double layer capacitors. In this work, we studied the charge storage mechanism of a model material - reduced graphene oxide (rGO) - in aqueous electrolyte using the combination of cavity micro-electrode, operando electrochemical quartz crystal microbalance (EQCM) and operando electrochemical dilatometry (ECD) tools. We evidence two regions with different charge storage mechanisms, depending on the cation-carbon interaction. Notably, under high cathodic polarization (region II), we report an important capacitance increase in Zn2+ containing electrolyte with minimum volume expansion, which is associated with Zn2+ desolvation resulting from strong electrostatic Zn2+-rGO interactions. These results highlight the significant role of ion-electrode interaction strength and cation desolvation in modulating the charging mechanisms, offering potential pathways for optimized capacitive energy storage. As a broader perspective, understanding confined electrochemical systems and the coupling between chemical, electrochemical and transport processes in confinement may open tremendous opportunities for energy, catalysis or water treatment applications in the future.

Mechanically Robust and Highly Conductive Poly(ionic liquid)/Polyacrylamide Double-Network Hydrogel Electrolytes for Flexible Symmetric Supercapacitors with a Wide Operating Voltage Range.

Flexible electronic devices, such as supercapacitors (SCs), place high demands on the mechanical properties, ionic conductivity, and electrochemical stability of electrolytes. Hydrogels, which combine flexibility and the advantages of both solid and liquid electrolytes, will meet the demand. Here, we report the synthesis of novel poly(ionic liquid)/polyacrylamide double-network (DN) (PIL/PAM DN) hydrogel electrolytes containing different metal salts via a two-step γ-radiation method. The resultant Li2SO4-1.0/PIL/PAM DN hydrogel electrolyte possesses excellent mechanical properties (tensile strength of 3.64 MPa, elongation at break of 446%) and high ionic conductivity (24.1 mS·cm-1). The corresponding flexible SC based on the Li2SO4-1.0/PIL/PAM DN hydrogel electrolyte (SC-Li2SO4) presents improved ion diffusion, ideal electrochemical double-layer capacitor behavior, good rate capability, and excellent cyclic stability. Moreover, symmetric SC-Li2SO4 achieves a wide operating voltage range of up to 1.5 V, with a maximum energy density of 26.0 W h·kg-1 and a capacitance retention of 94.1% after 10,000 galvanostatic charge-discharge cycles, owing to the deactivation of free water molecules by the synergistic effect of PIL, PAM, and SO42-. Above all, the capacitance of SC-Li2SO4 is well-maintained after overcharge, overdischarge, short circuit, extreme temperature, compression, and bending tests, indicating its high security and flexibility. This work reveals the enormous application potential of PIL-based conductive hydrogel electrolytes for flexible electronic devices.

High‐Strength Self‐Healable Supercapacitor Based on Supramolecular Polymer Hydrogel with Upper Critical Solubility Temperature

AbstractHere, poly(N‐acryloylglycinamide‐co‐vinyltriazole) p(NAGA‐co‐VTZ) supramolecular polymer hydrogel doped with carbonized and activated polypyrrole nanotubes as a high‐strength self‐healable material is presented for supercapacitors. Initially, the p(NAGA‐co‐VTZ) hydrogel films are synthesized by photopolymerization of N‐acryloylglycinamide and 1‐vinyl‐1,2,4‐triazole without the use of any cross‐linkers. The hydrogels demonstrated remarkable self‐healing ability via hydrogen bonding at temperatures above upper critical solubility temperature, excellent mechanical properties (0.86 MPa), large stretchability (1300%) and cut resistance. Subsequently, carbonized and ethanol/KOH‐activated polypyrrole nanotubes (acNTs) are prepared as the active material for electrochemical double‐layer capacitors (EDLC). Then, a symmetric self‐healable supercapacitor employing p(NAGA‐co‐VTZ) hydrogel, acNTs and aqueous 3 m KCl solution is assembled. Cyclic voltammetry and galvanostatic charge–discharge measurements show that the prepared device gives a specific capacitance of 282.62 F g−1 at 0.2 A g−1 and a high areal capacitance of 316.86 mF cm−2 at a scan rate of 10 mV s−1. Importantly, the supercapacitor operates over a wide voltage window (0–1.2 V) and provides excellent cyclic performance with capacitance retention of 97% after 10 000 cycles and 94% after self‐healing. In summary, the developed self‐healable supercapacitor exhibits considerable potential as a high‐performance energy storage device.

Tuning of Ionic Liquid–Solvent Electrolytes for High-Voltage Electrochemical Double Layer Capacitors: A Review

Electrochemical double-layer capacitors (EDLCs) possess extremely high-power density and a long cycle lifespan, but they have been long constrained by a low energy density. Since the electrochemical stability of electrolytes is essential to the operating voltage of EDLCs, and thus to their energy density, the tuning of electrolyte components towards a high-voltage window has been a research focus for a long time. Organic electrolytes based on ionic liquids (ILs) are recognized as the most commercially promising owing to their moderate operating voltage and excellent conductivity. Despite impressive progress, the working voltage of IL–solvent electrolytes needs to be improved to meet the growing demand. In this review, the recent progress in the tuning of IL- based organic electrolyte components for higher-voltage EDLCs is comprehensively summarized and the advantages and limitations of these innovative components are outlined. Furthermore, future trends of IL–solvent electrolytes in this field are highlighted.

Green polymer electrolyte and activated charcoal-based supercapacitor for energy harvesting application: Electrochemical characteristics

Abstract The aim of this study is to address the growing concern about microplastics in the ocean and their potential harm to human health through ingestion. The MPs issue is largely a result of the increasing demand for electronic devices and their components. To tackle this challenge, the research aimed to develop a green polymer electrolyte that used glycerol as a plasticizing agent to improve ionic conductivity. The polymer host included chitosan and polyvinyl alcohol and was composed of sodium acetate. To evaluate the performance of the polymer electrolyte, various analytical techniques were used, including impedance and electrochemical studies. The ionic conductivity of 7.56 × 10−5 S·cm−1 was recorded. The dielectric property study confirmed the ionic conduction process in the system and revealed the existence of non-Debye type relaxation, as indicated by asymmetric peaks of tanδ spectra. The alternating conductivity exhibits three distinguished regions. The polymer electrolyte was discovered to be electrochemically stable up to 2.33 V and capable of storing energy as a non-Faradaic electrochemical double-layer capacitor (EDLC). The cyclic voltammetry pattern is a leaf like shape. The EDLC was able to be charged and discharged up to 1 V, and it showed cyclability and could be used in low-voltage applications.

Structure and Electrical Properties of Polymer Electrolyte Based on Plasticized Chitosan Grafted Polymethyl Methacrylate (Ch-g-PMMA)- Magnesium Triflate for Electrochemical Double Layer Capacitor

Polymer electrolytes have received much attention as materials used in batteries, supercapacitors, sensors and solar cells. Most of the polymer electrolytes reported are based on synthetic polymer, therefore it is difficult to recycle as it has poor degradability and ends up being a waste. In recent years, biopolymers gained much interest in replacing environmentally unfriendly polymers. Various studies have been done to accomplish polymer electrolytes with high conductivity and long-term safety. This study’s objective is to prepare plasticized Ch-g-PMMA-based polymer electrolyte by introducing the magnesium triflate salt and glycerol plasticizer. The grafted polymer of Ch-g-PMMA was prepared using gamma (γ) radiation. The grafted polymer of Ch-g-PMMA with 0.4 g of Mg(Tf)2 and different concentrations of glycerol has been prepared by using the solution casting technique. To achieve this study, the prepared plasticized Ch-g-PMMA-Mg(Tf)2 polymer electrolytes are characterized by XRD, FTIR, EIS and LSV techniques. XRD was carried out to determine the change in crystallinity and the amorphous structure of the plasticized Ch-g-PMMA-Mg(Tf)2 polymer. FTIR reveals the occurrence of complexation between Ch-g-PMMA polymer, Mg(Tf)2 salt and glycerol plasticizer. The grafted Ch-g-PMMA-Mg(Tf)2 was added with different concentrations of glycerol from 0 to 50 wt%. The Ch-g-PMMA-Mg(Tf)2 polymer electrolyte with 50 wt% of glycerol shows the highest ionic conductivity of 1.50×10−4 S·cm−1 compared with other samples. The increase in mobility of ions and the number of charge carriers has enhanced ionic conductivity. Based on the LSV analysis, the highest conducting Ch-g-PMMA-Mg(Tf)2 polymer with 50 wt% of glycerol was found electrochemically stable up to 3.2 V. The goal of this study is to determine the structure and electrical properties as well as the window stability of plasticized Ch-g-PMMA-Mg(Tf)2. The best outcome was produced by adding the 50 wt% of glycerol into the Ch-g-PMMA-Mg(Tf)2 which increased further by 1 order of magnitude. HIGHLIGHTS The ionic conductivity of the Ch-g-PMMA increases by introducing magnesium triflate salt and glycerol plasticizer which enhance the amorphous state and decrease the crystallinity The prepared plasticized Ch-g-PMMA-Mg(Tf)2 polymer electrolytes are characterized by XRD, FTIR, EIS and LSV techniques The highest ionic conductivity are obtained by added 50 wt% glycerol to the grafted polymer CH-g-PMMA-Mg(Tf)2 which is 1.50×10−4 S·cm−1 GRAPHICAL ABSTRACT

Investigation of Several Bio Wastes as Sustainable Carbon Materials for Supercapacitor Manufacturing

This work presents various inquests on the utilization of bio wastes, agricultural wastes and sea shells to develop activated carbon as a veritable and sustainable electrode (terminals) substance for supercapacitors-(SC) also known as electrochemical double layer capacitors (EDLC) gadgets for preserving energy. We also looked at how electrode materials are processed with a view to improve or maximise the supercapacitor performance. This review entails how several bio wastes has been singed, synthesized and utilized to produce activated carbon material for long lasting, low-cost and environmentally-friendly EDLCs via the processes of pyrolysis, carbonization, physical activation and/or chemical activation with reagents and then characterized to show attributes making them suitable for application in supercapacitor manufacturing. Some of the features making the samples suitable for use as EDLC electrode materials include pore structure, very large surface area, power density, energy density, pore volume, cyclic stability specific capacitance, iodine adsorption with other attributes. This work also showcases how the various properties were determined by different tests including Brunauer-Emmett-Teller-(BET), Fourier Transform Infrared-(FTIR) Spectrometry, Field Emission Scanning Electron Microscopy-(FESEM), Raman-Spectroscopy, Scanning Electron Microscopy-(SEM), Energy Dispersive X-Ray-(EDX), X-Ray Diffraction-(XRD), TGA-Thermo-Gravimetric Analysis, Cyclic Voltammetry-(CV), Transmission Electron Microscopy-(TEM), and other procedures.