Activated Carbon Composite Electrode Research Articles

Preparation of activated carbon composite electrode from sugarcane bagasse and its application on energy storage devices

Preparation of activated carbon composite electrode from sugarcane bagasse and its application on energy storage devices

Screen-Printed Stretchable Supercapacitors Based on Tin Sulfide-Decorated Face-Mask-Derived Activated Carbon Electrodes with High Areal Energy Density

Screen-Printed Stretchable Supercapacitors Based on Tin Sulfide-Decorated Face-Mask-Derived Activated Carbon Electrodes with High Areal Energy Density

2-anilino-1,4-naphthoquinone and 2-benzylamino-1,4-naphthoquinone with activated carbon composite electrodes for supercapacitor application

This study focuses on the synthesis and electrochemical characterization of two naphthoquinone derivatives, 2-anilino-1,4-naphthoquinone (ANQ) and 2-benzylamino-1,4-naphthoquinone (BNQ), as promising composite materials with activated carbon (AC) for supercapacitor applications. Current supercapacitor electrodes use AC as the active material; however, the specific capacitance is limited by its surface area due to its electric double layer capacitive behavior. ANQ and BNQ were employed as composite material with AC to resolve this issue using pseudocapacitive behavior, which combines surface and chemical redox behavior for increased capacitance. First, ANQ and BNQ were analyzed using various techniques, including nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and electrospray ionization mass spectroscopy, to confirm their molecular structures. Then, the composite electrodes AC-ANQ and AC-BNQ were thoroughly investigated through scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller analysis to understand their surface morphology, elemental composition, and porosity. Notably, at an AC:NQ derivative weight ratio of 3:1, ANQ and BNQ efficiently occupied AC pores, a vital factor in achieving superior electrochemical performance. Finally, electrochemical characterization, including cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge testing, demonstrated promising results for ANQ-AC and BNQ-AC composite electrodes with high specific capacitances of 134 and 174 F g−1, respectively. Additionally, these composite electrodes exhibited exceptional cycle stability over 10,000 cycles at high current densities. The enhanced electrochemical results are attributed to the pseudocapacitive behavior of quinone derivatives. ANQ and BNQ in particular have an extra aromatic ring attached to the naphthoquinone molecule which allows for additional π-π van der Waals stacking interactions between ANQ and BNQ, and AC which is theorized to be the reason for the excellent cycling stability. Our findings show the promise of ANQ and BNQ as composite materials with AC for enhancing supercapacitor electrode performance.

Hydrothermally Grown Zinc Oxide Nanostructures@Carbon Composites for Supercapacitor Application

A simple approach for growing porous nanostructured zinc oxide (ZnO) and making its well‐dispersed nanocomposite with activated carbon (AC) is demonstrated. Synthesis is done hydrothermally at 140 °C for 10 hours. X‐ray diffraction (XRD), energy‐dispersive X‐ray (EDX), and scanning electron microscope (SEM) measurements confirm the formation of crystalline ZnO nanoparticles with flower‐shaped morphology comprising clusters of nanopetals. ZnO and its composite with AC are used to fabricate symmetric hybrid supercapacitors. The electrochemical performance of ZnO electrode is compared to ZnO–AC composite electrode using 1 M Na2SO4 aqueous electrolyte. The electrochemical performance evaluated by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) demonstrates enhanced charge storage in ZnO–AC electrodes. The specific capacitance values of ZnO and ZnO–AC‐based electrodes are found to be 214 and 298 F g−1 respectively at a current density of 1 A g−1 and the energy densities are 29.72 and 48.39 Wh kg−1 respectively at power density of 1 kW kg−1. The porous space between ZnO nanopetals and its high surface area geometry coupled with complementing properties of AC seems to facilitate a synergistic effect between ZnO's faradaic and AC's electric double‐layer charge storage mechanisms, thus leading to enhanced specific capacitance with superior performance.

Glycerol Electrocatalytic Reduction Using an Activated Carbon Composite Electrode: Understanding the Reaction Mechanisms and an Optimization Study

The conversion of biomass-derived glycerol into valuable products is an alternative strategy for alleviating energy scarcity and environmental issues. The authors recently uncovered an activated carbon composite electrode with an Amberlyst-15 mediator able to generate 1,2-propanediol, diethylene glycol, and acetol via a glycerol electrocatalytic reduction. However, less attention to mechanistic insights makes its application to industrial processes challenging. Herein, two proposed intermediates, acetol and ethylene glycol, were employed as the feedstocks to fill the gap in the mechanistic understanding of the reactions. The results discovered the importance of acetol in producing 1,2-propanediol and concluded the glycerol electrocatalytic reduction process has a two-step reduction pathway, where glycerol was initially reduced to acetol and consecutively hydrogenated to 1,2-propanediol. At 353 K and 0.28 A/cm2, 1,2-propanediol selectivity achieved 77% (with 59.8 C mol% yield) after 7 h of acetol (3.0 mol/L) electrolysis. Finally, the influences of the temperature, glycerol initial concentration, and current density on the glycerol electrocatalytic reduction were evaluated. The initial step involved the C-O and C-C bonds cleavage in glycerol plays a crucial role in producing either acetol or ethylene glycol intermediate. This was controlled by the temperature, which low to moderate value is needed to maintain a selective acetol-1,2-propanediol route. Additionally, medium glycerol initial concentration reduced the hydrogen formation and indirectly improved 1,2-propanediol yield. A mild current density raised the conversion rate and minimized the growth of intermediates. At 353 K and 0.21 A/cm2, glycerol (3.0 mol/L) electrocatalytic reduction to 1,2-propanediol reached the maximum yield of 42.3 C mol%.

Activated carbon-based electrodes for two-steps catalytic/ electrocatalytic reduction of glycerol in Amberlyst-15 mediator

Redox mediators supply an effective way to promote electrons (and protons) transport between the electrode and substrate without being in direct physical contact with the electrode. Here, the carbon-based electrodes with Amberlyst-15 as the redox mediator were used in the electrocatalytic reduction to investigate their ability to indirectly convert glycerol into 1,2-propanediol. The process aims to study the influence of different activated carbon compositions (60%, 70%, 80%, and 90% of total weight) in the activated carbon composite (ACC) electrodes on the electrochemical properties, reaction mechanisms, and selectivity of the yielded products. Their electrochemical behavior and physicochemical properties were determined by cyclic voltammetry (CV) and chronoamperometry (CA), followed by FESEM-EDX for the selected ACC electrode. Electroactive surface area (EASA) plays a role in glycerol mass transport and electrons transfer. EASA of 60ACC, 70ACC, 80ACC, and 90ACC (geometrical surface area of 0.50 cm2) were 19.62, 24.50, 36.74 and 30.83 cm2, respectively. With the highest EASA, 80ACC enhanced the mass transport and electrons transfer process that eventually improved its electrocatalytic activity. It outperformed other ACC electrodes by generating Amberlyst-15 radicals (A-15•-) with high current density at low potential (−0.5 V vs. Ag/AgCl). A-15•- served as the electron-donor for the homogeneous redox reaction with glycerol in delivering highly reactive glycerol radical for further intermediates development and generated 1,2-propanediol at −2.5 V vs. Ag/AgCl (current density of −0.2018 A cm−2). High activated carbon content portrayed a dominant role in controlling EASA and favored consecutive acetol-1,2-propanediol production through the C–O bond breakage. From the galvanostatic electrolysis, 1,2-propanediol selectivity was higher on 80ACC (88.6%) compared to 60ACC (61.4%), 70ACC (70.4%) and 90ACC (72.5%). Diethylene glycol formation was found to be the side reaction but preferred low activated carbon percentage in 60ACC and 70ACC.

Hydrothermal synthesis of MnO2@graphene/activated carbon composite electrode with enhanced electrochemical performance for supercapacitor applications

We report the preparation of an electrode material made up of MnO2/graphene/ activated carbon ternary composite by hydrothermal method for supercapacitor (SC) applications. The prepared ternary composite has been characterized by using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Raman spectroscopy measurements. The prepared objective electrode has been investigated using galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) measurements in a 3-electrode system using 3M KOH aqueous electrolyte for the analysis of their electrochemical performance. The prepared MnO2 /graphene/activated carbon composite results in maximum capacitance of ∼493.57 F/g at 5 mV/s using CV and moreover the highest capacitance obtained from the GCD measurement is ∼485.29 F/g at 1 A/g. The long-term cycle stability of the composite electrode is also demonstrated and it shows outstanding cyclic performance where 97% of capacitance is left over 5000 cycles at 1 A/g. Therefore, the composite shows good charge storage performance, as well as tremendous cycle stability and that, reveal the synthesized ternary composite can be a suitable electrode for SC applications.

High-rate operation of sulfur/mesoporous activated carbon composite electrode for all-solid-state lithium-sulfur batteries

High-rate operation of sulfur/mesoporous activated carbon composite electrode for all-solid-state lithium-sulfur batteries

Nitrogen-Doped Seamless Activated Carbon Electrode with Excellent Durability for Electric Double Layer Capacitor

The electric double layer capacitor (EDLC) using a seamless activated carbon electrode shows an excellent durability against high voltage charging compared to the conventional activated carbon composite electrode. In this study, the authors focused on nitrogen-doping as a surface modification to further improve the electrochemical durability of the seamless electrode. The EDLC using the nitrogen-doped seamless activated carbon electrode achieved the volumetric capacitance of 18 F cm−3 (based on the galvanostatic method, 80 mA g−1, 0–2.5 V, 40 °C) and the capacitance retention of 83% after the float durability test (3.5 V, 70 °C, 100 h) using a typical propylene carbonate electrolyte. The volumetric capacitance is comparable to that (14 F cm−3) of the conventional activated carbon, such as YP50F, and the retention is much higher than that (76%) of the pristine seamless activated carbon. The authors concluded that the extremely excellent durability of the nitrogen-doped seamless activated carbon electrode is due to (i) the stable electric network arising from the binder-less monolithic structure and (ii) nitrogen surface functionalities that suppresses micropore blocking and internal resistance change caused by electrochemical decomposition deposits. (184 words).

Naphthalene Derivative Supported Activated Carbon Composite Electrode with Enhanced Capacitance and Potential Window

Naphthalene Derivative Supported Activated Carbon Composite Electrode with Enhanced Capacitance and Potential Window

Mixtures of glyme and aprotic-protic ionic liquids as electrolytes for energy storage devices.

Ionic liquids (ILs) have been proven to be promising electrolytes for electrochemical energy storage devices such as supercapacitors and lithium ion batteries. In the last years, due to deficiency in storage of lithium on earth, innovative systems, such as sodium-based devices, attracted considerable attention. IL-based electrolytes have been proposed also as electrolytes for these devices. Nevertheless, in the case of these systems, the advantages and limits of IL-based electrolytes need to be further investigated. In this work we report an investigation about the chemical-physical properties of mixtures containing bis(2-methoxyethyl)ether diglyme (2G), which is presently considered as one of the most interesting solvents for sodium-based devices, and the ionic liquids 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) and 1-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PyrH4TFSI). The conductivities, viscosities, and densities of several mixtures of 2G and these ILs have been investigated. Furthermore, their impact on the electrochemical behaviour of activated carbon composite electrodes has been considered. The results of this investigation indicate that these mixtures are promising electrolytes for the realization of advanced sodium-based devices.

Ultra-high-voltage capacitor based on aluminum electrolytic–electrochemical hybrid electrodes

Low working voltage hinders the wide application of a single electrochemical capacitor, while the rapidly developing industry of electronic components urgently needs a kind of device combining the advantages of high voltage and energy capacity. This work successfully prepared a flexible packaging aluminum electrolytic–electrochemical hybrid capacitor with high working voltage and capacitance, using aluminum electrolytic capacitor anode foil as anode and activated carbon composite electrodes as cathode. The results show that the working voltage reaches 105 V. The single capacitance reaches 580 μF at a current of 100 mA cm−2, which is double than that of the traditional aluminum electrolytic capacitors at the same size. The hybrid capacitor exhibits superior energy storage density and rapid charge–discharge capacity. The gravimetric energy density and volume energy density for the hybrid capacitor is 0.49 J g−1 and 0.62 J cm−3, respectively. It also exhibits excellent cycling performance without obvious capacitance capacity fading. The increase in the energy density of the hybrid capacitor is mainly due to the use of aluminum electrolytic capacitor materials for the anode and the use of electrochemical capacitor material for the cathode, which increases the operating voltage and the specific capacitance.

An ether-functionalised cyclic sulfonium based ionic liquid as an electrolyte for electrochemical double layer capacitors

A novel cyclic sulfonium cation-based ionic liquid (IL) with an ether-group appendage and the bis{(trifluoromethyl)sulfonyl}imide anion was synthesised and developed for electrochemical double layer capacitor (EDLC) testing. The synthesis and chemical-physical characterisation of the ether-group containing IL is reported in parallel with a similarly sized alkyl-functionalised sulfonium IL. Results of the chemical-physical measurements demonstrate how important transport properties, i.e. viscosity and conductivity, can be promoted through the introduction of the ether-functionality without impeding thermal, chemical or electrochemical stability of the IL. Although the apparent transport properties are improved relative to the alkyl-functionalised analogue, the ether-functionalised sulfonium cation-based IL exhibits moderately high viscosity, and poorer conductivity, when compared to traditional EDLC electrolytes based on organic solvents (propylene carbonate and acetonitrile). Electrochemical testing of the ether-functionalised sulfonium IL was conducted using activated carbon composite electrodes to inspect the performance of the IL as a solvent-free electrolyte for EDLC application. Good cycling stability was achieved over the studied range and the performance was comparable to other solvent-free, IL-based EDLC systems. Nevertheless, limitations of the attainable performance are primarily the result of sluggish transport properties and a restricted operative voltage of the IL, thus highlighting key aspects of this field which require further attention.

Anodic Degradation of 2-Chlorophenol by Carbon Black Diamond and Activated Carbon Composite Electrodes

A carbon black diamond composite electrode with 20% carbon black (20CBD) and activated carbon composite (ACC) electrode were prepared and used as anodes for 2-chlorophenol electro-oxidation. The electro-oxidation behaviors of 200mg/L 2-chlorophenol on 20CBD and ACC anodes were investigated by cyclic voltammetry in aqueous solutions of 0.5M H2SO4 (pH 0.55) and 0.25M Na2SO4 (pH 7). Results indicated that the 20CBD and ACC electrodes are more active at low pH than at high pH and that no oxidation peak appears on the ACC electrode. The performance of the 20CBD and ACC electrodes during degradation of 200mg/L 2-chlorophenol was investigated in an aqueous solution of pH 3 with 0.25M Na2SO4 as the supporting electrolyte and applied current density of 30mA/cm2. Results showed that the 20CBD electrode produced the best degradation rate, COD removal efficiency, and current efficiency. The degradation efficiencies of the 20CBD and ACC electrodes after 6h were 96% and 82.5%, respectively. The effects of solution pH, current density, and supporting electrolyte on the performance of the 20CBD were further investigated, and results showed that higher degradation rates are obtained at lower pH and with Na2SO4 as the supporting electrolyte. Removal efficiency also increased with increasing current density.

Charge storage performance of lithiated iron phosphate/activated carbon composite as symmetrical electrode for electrochemical capacitor

In this study, a symmetric electrochemical capacitor was fabricated by adopting a lithium iron phosphate (LiFePO4)-activated carbon (AC) composite as the core electrode material in 1.0 M Na2SO3 and 1.0 M Li2SO4 aqueous electrolyte solutions. The composite electrodes were prepared via a facile mechanical mixing process. The structural properties of the nanocomposite electrodes were characterised by scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) analysis. The electrochemical performances of the prepared composite electrode were studied using cyclic voltammetry (CV), galvanostatic charge–discharge (CD) and electrochemical impedance spectroscopy (EIS). The experimental results reveal that a maximum specific capacitance of 112.41 F/g was obtained a 40 wt% LiFePO4 loading on an AC electrode compared with that of a pure AC electrode (76.24 F/g) in 1 M Na2SO3. The improvement in the capacitive performance of the 40 wt% LiFePO4–AC composite electrode is believed to be attributed to the contribution of the synergistic effect of the electric double layer capacitance (EDLC) of the AC electrode and pseudocapacitance via the intercalation/extraction of H+, OH−, Na+ and SO32− and Li+ ions in LiFePO4 lattices. In contrast, it appears that the incorporation of LiFePO4 into AC electrodes does not increase the charge storage capability when Li2SO4 is used as the electrolyte. This behaviour can be explained by the fact that the electrolyte system containing SO42− only exhibits EDLC in the Fe-based electrodes. Additionally, Li+ ions that have lower conductivity and mobility may lead to poorer charge storage capability compared to Na+ ions. Overall, the results reveal that the AC composite electrodes with 40 wt% LiFePO4 loading on a Na2SO3 neutral electrolyte exhibit high cycling stability and reversibility and thus display great potential for electrochemical capacitor applications.

LiFePO<sub>4 </sub>- Activated Carbon Composite Electrode as Symmetrical Electrochemical Capacitor in Mild Aqueous Electrolyte

In this study, a symmetric electrochemical capacitor has been fabricated by adopting the lithiated compound (LiFePO4)-activated carbon (AC) composite as the core electrode materials. The electrochemical performances of the prepared supercapacitor were studied using cyclic voltammetry (CV) in 1.0 M Na2SO3 solution. Experimental results reveal that the maximum specific capacitance of 112.41 F/g is obtained in 40 wt % LiFePO4 loading on AC electrode in comparison to that of pure AC electrode (76.24 F/g) in 1 M Na2SO3. The enhanced capacitive performance of the 40 wt % LiFeO4 –AC composite electrode is believed attributed to the contribution of synergistic effect of electric double layer capacitance (EDLC) on the surface of AC as well as pseudocapacitance via intercalation/extraction of Na+, SO32-and Li+ ions in LiFePO4 lattices. The composite electrodes can sustain a stable capacitive performance at least 1000 cycles with only ~5 % specific capacitance loss after 1000 cycles. Based on the findings above, 40 wt % LiFeO4 –AC composite electrodes which utilise low cost materials and environmental friendly electrolyte is worth being investigated in more details.

Relationship between capacitance of activated carbon composite electrodes measured at a low electrolyte concentration and their desalination performance in capacitive deionization

Capacitive deionization (CDI) has attracted attention as a novel desalination process, which would be one of solutions to global water scarcity. In this process, a porous electrode is the most important component, providing high capacitance and subsequent large desalination capacity. Activated carbon satisfies this requirement and is an economically competitive material over other types of carbon, so that lots of studies have been carried using various activated carbons. However, the relationship between capacitance and desalination performance remains unclear, especially at low electrolyte concentrations. In this study, we investigated the relationship between capacitance and desalination performance using various activated carbon composite electrodes. Capacitance was specifically measured at a low electrolyte concentration (0.01M NaCl), in which condition the CDI works effectively, and was transformed to charge capacity, assuming that 1.2V was applied to the system. The results showed that deionization capacity had a good linear relationship to the charge capacity evaluated from capacitance. In particular, we found out that 60–80% of the charge capacity (0.01M) could be utilized in deionization. Also, the ratio became 50–60% with the charge capacity evaluated by capacitance measured at a high electrolyte concentration (1M NaCl). This approach allows simple estimation of desalination performance from capacitance of electrodes, which would eventually make the systematic design and characterization of CDI electrodes convenient.

Nanosized Fe3O4-modified activated carbon for supercapacitor electrodes

Nanosized Fe3O4-modified activated carbon composites for supercapacitor electrodes have been investigated. Structural and morphological characterizations of activated materials are carried out using X-ray diffraction and scanning electron microscopy, respectively. The electrochemical performances of the composite electrodes are evaluated by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The experimental results show that the specific capacitances of the 10 wt % Fe3O4-modified activated carbon composite electrode (154.3 F g−1) is highly improved compared with that of Fe3O4 (78.5 F g−1) and AC (79.2 F g−1) at the current density of 5 mA cm−2, respectively. The charge/discharge tests show that it could retain 79.6% of its initial capacitance over 1000 cycles, suggesting its potential application for the fabrication of high-quality supercapacitors.

Copper nanocrystal modified activated carbon for supercapacitors with enhanced volumetric energy and power density

Copper nanocrystals homogeneously dispersed in activated carbon (AC) were synthesized by an in situ solution-based absorption–reduction method, and the resulting composites were characterized and studied for supercapacitor application. The effects of copper nanocrystals and their content on the electrochemical properties of the obtained AC composites were investigated using multiple techniques, including X-ray photoelectron spectroscopy, nitrogen sorption analysis, cyclic voltammetry, galvanic cycling, and electrochemical impedance spectroscopy. Results showed that the addition of copper nanocrystals in the AC composites has little effect on the surface area and porosity of AC, and is helpful to reduce its equivalent series resistance, which is favorable to achieve higher charge/discharge rate and improve its power density when used as electrodes for supercapacitors. Copper nanocrystals and the partially oxidized phase CuO act as pseudo-active materials and improve the capacity of the AC composite electrode. The volumetric capacity, energy density, and power density of copper nanocrystal modified activated carbon are much higher than those of AC and AC mechanically mixed with copper particles. Copper nanocrystal modified AC presents a high volumetric capacitance of 62 F cm−3, more than twice of that of unmodified AC.

Ultrahigh-performance nonaqueous electric double-layer capacitors using an activated carbon composite electrode with alginate

An activated carbon composite electrode for nonaqueous electric double-layer capacitors was prepared with alginate. A model cell with this electrode showed an ultrahigh rate capability, presumably because of the high affinity of alginate for activated carbon, which decreased the internal resistance of the composite electrode.