Active Electrode Material For Supercapacitors Research Articles

Ternary nanocomposite of RAFT‐polymerized DMAEMA‐functionalized graphene oxide, manganese dioxide and polyaniline as active electrode material for supercapacitor

AbstractGraphene and its derivatives are promising energy storage devices due to their high specific surface area, chemical and thermal durability and high charge transfer power. Still, their stacking and aggregate behavior can limit their practical application. To address this issue, reversible addition–fragmentation chain‐transfer (RAFT) polymerization as controlled radical polymerization was applied to functionalize the surface of graphene oxide with poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) via the ‘grafting from’ method. This strategy enhances the distance between graphene sheets by occupying physical volume while improving effective charge transfer through tertiary amine groups participating in the doping process. X‐ray diffraction was used to determine interlayer spacing after polymer grafting, which increased from 0.28 to 1.71 nm after polymer grafting. The hybridization of materials with diverse properties was used to enhance charge transfer capability for supercapacitor applications. PDMAEMA‐functionalized graphene oxide, nano‐manganese dioxide and polyaniline were combined to create a successful nanocomposite as electrode active material. The morphological structure and chemical composition of the synthesized nanocomposite were analyzed, and its electrochemical performance was evaluated using cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The nanocomposite exhibited a maximum specific capacitance, energy density and power density of 364.72 F g−1 (at a scan rate of 50 mV s−1), 239.08 Wh kg−1 and 678.34 W kg−1, respectively. The final nanocomposite's energy storage capacity significantly increased compared to the individual components due to hybridization's synergistic impact, reducing charge transfer resistance. © 2024 Society of Industrial Chemistry.

Covalently Functionalized Graphene Derivatives as Active Electrode Materials for Supercapacitors

Research efforts for supercapacitor electrode materials have become increasingly important due to the high demand for long-lasting, high-performing and environmentally friendly portable energy storage devices. Graphene-based materials and their hybrids have been shown to be very promising candidates for meeting these requirements. This short review summarizes recent advances in the development of graphene derivatives and focuses in particular on materials derived from graphite fluoride. Covalent graphene derivatives belong to a progressive class of highly efficient materials with tailorable structural and physicochemical properties that can be adapted to meet specific capacitive charge storage requirements, and, thus, enhance the most effective development of the energy storage field.

Chitosan-derived carbon aerogel nanocomposite as an active electrode material for high-performance supercapacitors

The valorization of shrimp wastes to develop advanced materials brings economic and environmental advantages. This paper presents a facile and eco-friendly synthesis of shrimp chitosan-derived carbon (CCS) and CCS/[email protected](OH)2 (CSSN) aerogel nanocomposite for supercapacitor application, in which NiO and Ni(OH)2 nanoparticles were tightly attached to the porous surface of CCS aerogel. As a result, CCSN-300 aerogel carbonized at 300 °C has high porosity and electrical conductivity and demonstrates its potential as an active electrode material for supercapacitors. The CCSN-300 aerogel material electrode exhibits a high capacitance of 316 mAh g−1 at 1.0 A g−1. Furthermore, the CCS//CCSN-300 device had a capacitance of 209 F g−1 at 1.0 A g−1 and over 84% remaining after the 10,000 cycles. Moreover, it has a high energy density of 65 Wh kg−1 at a power density of 1500 W kg−1. The results demonstrate that chitosan-derived carbon composites hold great promise in high application efficiency for energy storage.

Sustainable Supercapacitors Based on Polypyrrole-Doped Activated Biochar from Wood Waste Electrodes

The synthesis of high-performance carbon-based materials from biomass residues for electrodes has been considered a challenge to achieve in supercapacitor-based production. In this work, activated biochar has been prepared as the active electrode material for supercapacitors (SCs), and an effective method has been explored to boost its capacitive performance by employing polypyrrole (PPy) as a biochar dopant. The results for physicochemical characterization data have demonstrated that PPy doping affects the biochar morphology, specific surface area, pore structure, and incorporation of surface functionalities on modified biochar. Biochar-PPy exhibited a surface area of 87 m2 g−1, while pristine biochar exhibited 1052 m2 g−1. The SCs were assembled employing two electrodes sandwiched with PVA solid-state film electrolyte as a separator. The device was characterized by standard electrochemical assays that indicated an improvement of 34% in areal capacitance. The wood electrodes delivered high areal capacitances of 282 and 370 mF cm−2 at 5 mA cm−2, for pure biochar and biochar doped with PPy, respectively, with typical retention in the capacitive response of 72% at the end of 1000 cycles of operation of the supercapacitor at high current density, indicating that biochar-PPy-based electrode devices exhibited a higher energy density when compared to pure biochar devices.

3D Hierarchically Structured Tin Oxide and Iron Oxide-Embedded Carbon Nanofiber with Outermost Polypyrrole Layer for High-Performance Asymmetric Supercapacitor.

Herein, unique three-dimensional (3D) hierarchically structured carbon nanofiber (CNF)/metal oxide/conducting polymer composite materials were successfully synthesized by combinations of various experimental methods. Firstly, base CNFs were synthesized by carbonization of electrospun PAN/PVP fibers to attain electric double-layer capacitor (EDLC) characteristics. To further enhance the capacitance, tin oxide (SnO2) and iron oxide (Fe2O3) were coated onto the CNFs via facile hydrothermal treatment. Finally, polypyrrole (PPy) was introduced as the outermost layer by a dispersion polymerization method under static condition to obtain 3D-structured CNF/SnO2/PPy and CNF/Fe2O3/PPy materials. With each synthesis step, the morphology and dimension of materials were transformed, which also added the benign characteristic for supercapacitor application. For the practical application, as-synthesized CNF/SnO2/PPy and CNF/Fe2O3/PPy were applied as active materials for supercapacitor electrodes, and superb specific capacitances of 508.1 and 426.8 F g-1 (at 1 A g-1) were obtained (three-electrode system). Furthermore, an asymmetric supercapacitor (ASC) device was assembled using CNF/SnO2/PPy as the positive electrode and CNF/Fe2O3/PPy as the negative electrode. The resulting CNF/SnO2/PPy//CNF/Fe2O3/PPy device exhibited excellent specific capacitance of 101.2 F g-1 (at 1 A g-1). Notably, the ASC device displayed a long-term cyclability (at 2000 cycles) with a retention rate of 81.1%, compared to a CNF/SnO2//CNF/Fe2O3 device of 70.3% without an outermost PPy layer. By introducing the outermost PPy layer, metal oxide detachment from CNFs were prevented to facilitate long-term cyclability of electrodes. Accordingly, this study provides an effective method for manufacturing a high-performance and stable supercapacitor by utilizing unique 3D hierarchical materials, comprised of CNF, metal oxide, and conducting polymer.

Synthesis of manganese ferrite/graphene oxide nanocomposite and investigation of its supercapacitor behaviors

Currently, researchers are struggling with the development of energy storage systems, like high energy density supercapacitors, with cheap cost and high stability. Herein research we present a facile preparation and evaluation of the manganese ferrite/graphene oxide (MnFe2O4/GO) nanocomposite electrochemical behavior as active electrode material in supercapacitors. The chemical composition and morphology were specified with different physicochemical characterization techniques. The TEM and FESEM images exhibit MnFe2O4 semi-spherical nanoparticles on GO plates. The prepared electrodes performance were proceeded with charge-discharge galvanostatic measurement (GCD), electrochemical impedance (EIS), and cyclic voltammetry (CV). The specific capacity value of MnFe2O4/GO new composite determined 298 F g−1 in 1 A/g current density. Also MnFe2O4/GO electrodic composite shows acceptable GCD stability, by maintaining its original capacity of 92% at 500 cycles. The EIS analysis also displays low internal resistance of MnFe2O4/GO compared to other electrodes in the same conditions. In addition to experimental analysis, density functional theory was also used to get a more accurate understanding of the electrochemical behavior of electrode materials. The theoretical results showed that with the formation of MnFe2O4/GO nanocomposite, the electron conductivity is improved (energy gap decreases to 0.019 eV) and leads to an increase in supercapacitor performance, which is in agreement with the experimental results.

Preparation of two-dimensional manganese dioxide nanosheets by stirred media milling and its application as supercapacitor electrode materials

A novel top-down approach for ultrathin two-dimensional (2D) MnO2 nanosheets preparation in stirred media mill as an active electrode material for supercapacitors is reported in this work. The milling behavior with time was analyzed, followed by the electrochemical analysis of a milled sample. The XRD peak shows that crystallinity of prepared 2D MnO2 nanosheets decreased. Scanning Electron Microscopy (SEM) depicted a plate-like structure of a few hundred-nanometer lateral dimension. High-Resolution Transmission Electron Microscopy (HR-TEM) and Atomic Force Microscopy (AFM) further confirmed the formation of 2D MnO2 nanosheets. The cyclic voltammetry gave the specific capacitance of 356.11 F/g.

Hierarchically Porous Graphene Aerogels with Abundant Oxygenated Groups for High-Energy-Density Surpercapacitors

A hierarchically porous graphene aerogel (HP-GA) with abundant oxygenated groups and hand-tearing bread-like macromorphology is achieved by a sacrificial MnO2 template approach. Oxygenated groups on graphene sheets improve the wettability of HP-GA to an aqueous electrolyte and contribute to pseudocapacitance. The chlorine (Cl2) gas as a result of the reaction of MnO2 and HCl is responsible for the formation of the hierarchically porous microstructure and hand-tearing bread-like macromorphology, ensuring a large electrolyte accessible surface area within the electrodes. When used as the active electrode material in supercapacitors, HP-GA exhibits a large specific capacitance of 284 F g–1 at 1 A g–1 and ultrahigh energy density of 10 Wh kg–1 at 250 W kg–1 in an aqueous electrolyte. This work provides a versitile, simple, and easy to control way to alter the microstructure and macromorphology of graphene-based areogels that have promising applications in many areas, including adsorption, energy storage, heat insulation, acoustical insulation, and intelligent sensing system.

Recent development of carbon electrode materials for electrochemical supercapacitors

Supercapacitors have gained much attention due to their remarkable merits such as stable cycle performance, high power density and excellent charge and discharge performance at high rate. From this perspective, carbon-based materials are widely explored as the active electrode materials for supercapacitors by taking advantages of hierarchical porous structure, excellent chemical stability, multistage pore structure, high surface area, and excellent conductivity. Various studies have explored many methods to utilize carbon-based electrodes. The large amount of defects inside carbon materials including functional groups, heteroatoms, name as foreign-doping, can provide pseudocapacitance. Meanwhile, self-doping (voids, vacancies, defects, etc.) may also enhance the electric double-layer capacitance. In this context, a brief overview of carbon materials for supercapacitor is expounded, including their characteristics, development process and the future challenges, providing a referential guide to those new to this field.

Samarium hydroxide nanorolls anchored graphitic carbon nitride nanosheets: An active electrode material for supercapacitors

This study uses the simple precipitation technique to develop a novel nanocomposite material comprised of samarium hydroxide nanorolls attached to the surface of graphitic carbon nitride nanosheets as active electrode materials for supercapacitors. The unique texture (morphology) of Sm(OH)3 nanorolls attached to the g-C3N4 nanosheets aid in creates a substantial number of active sites during redox reactions. Sm(OH)3/g-C3N4 nanocomposite exhibits a specific capacitance of 586 F g−1 at 1 A g−1 in 3 M LiOH, though its constituents Sm(OH)3 (227.87 Fg−1 at 1 A g−1) and g-C3N4 (135.55 Fg−1 at 1 Ag−1). Benefiting from its morphological structure, the prepared nanocomposite (SCN20) achieved a high cyclability of 97.5% even after 3000 continuous cycles and coulombic efficiency of 95.1%. Additionally, an asymmetric supercapacitor device was constructed by employing a positive electrode as Sm(OH)3/g-C3N4 nanocomposite (SCN20) and negative electrode as activated carbon (AC), which exhibits a high energy density of 37.23 W h kg−1 with the respective power density of 3.5 kW kg−1. This investigation is about the exciting morphology of the novel nanocomposites and their synergetic reaction existing between them, which bring forth the nanoengineering of as-synthesized active materials for the application in supercapacitors.

3D juniperus sabina-like Ni/Co metal-organic framework as an enhanced electrode material for supercapacitors

Metal-organic frameworks (MOFs) haves been intensively studied as active electrode materials for supercapacitors. However, few studies have been systematically investigated the electrochemical performance of MOFs as electrode materials by adjusting the raw material components and reaction conditions to regulate and control MOFs morphology structures. Herein, a series of nickel/cobalt MOFs (Ni/Co-MOFs) with different morphology structures were synthesized by one-pot solvothermal method via adjusting raw material components and reaction conditions. Results show that three-dimensional (3D) juniperus sabina-like Ni/Co-MOF has optimal electrochemical performance with a specific capacitance of 982.5 ​F/g at 0.5 A/g. Meanwhile, the asymmetric supercapacitor exhibits the capacitance of 132.0 ​F/g at 0.5 A/g, and the corresponding energy density and power density are 46.9 ​Wh/kg and 400.0 ​W/kg, respectively. The work presents a novel strategy to regulate and control the morphology structures of MOFs by adjusting the raw material components and reaction conditions to achieve the optimal electrochemical performance of MOFs.

Electrochemical Sensitization of Activated Carbon by Microporous MOF for Supercapacitor Applications

AbstractThe remarkable performance of activated carbon as active electrode material in supercapacitors enabled its large‐scale industrialization. Herein, the utilization of facile physical mixing process of microporous, chemically robust, Zr‐based metal‐organic framework for surface‐modification of activated carbon to enhance its charge retention capacitance is reported. In this approach, the high surface area of the microporous MOF increases the active surface area of the activated carbon, providing an extra layer with facilitated electrolyte diffusion properties that effectively modulates the solid–electrolyte interface. A critical optimal coverage of 5wt % by the MOF crystallites is identified, resulting in increased specific capacitance of the activated carbon by ∼80 %, as compared to the pristine carbon. At higher MOF coverage, the poor electronic conductivity of the MOF hindered the inter‐grain charge mobilization within the activated carbon, thus adversely affecting the overall capacitive performance.

A hierarchical porous aerogel nanocomposite of graphene/NiCo2S4 as an active electrode material for supercapacitors

A three-dimensional reduced graphene oxide/nickel-cobalt sulfide (RGO/NiCo2S4) aerogel was fabricated by an efficient and facile one-step hydrothermal approach. The NiCo2S4 needle-like structure consisted of many small nanoparticles well attached to the surface of the RGO sheet. The prepared aerogel had high porosity and conductivity. As an active electrode material for supercapacitors, the RGO/NiCo2S4 aerogel exhibited a large capacitance of 813 F g−1 at 1.5 A g−1. Besides, the asymmetric supercapacitor (RGO/NiCo2S4 aerogel//RGO) showed a Cs of 45.3 F g−1 at 1.0 A g−1 and a suitable remaining capacitance of over 84.3 % after 2000 cycles. The asymmetric supercapacitor had a high energy density of 40.3 Wh kg−1 at 375.0 W kg−1 and a power density of 26.2 kW kg−1 at 3.7 kWh kg−1, which suggests this device has great potential applications in energy storage.

Synergistic Activation for Synthesis of Sulfur and Oxygen Co–Doped Porous Carbons and Their Application for Dye Adsorption and Supercapacitor

AbstractEnvironmentally friendly activation strategies for synthesis of heteroatom‐doped porous carbons are extremely welcome. Here, K2SO4 and NaCl‐KCl were introduced simultaneously to prepare sulfur/oxygen co‐doped porous carbons (SPC). By adopting phenolic resin (PF) as the carbon source, the optimal SPC sample with a large surface area of 1838 m2 g−1 and pore volume of 1.18 cm3 g−1 was successfully prepared. Structure characterizations demonstrated that K2SO4 mainly accounted for the pore formation while NaCl‐KCl had a confinement effect on the carbon loss. Finally, as a multifunctional adsorbent, the maximum capacity for SPC‐1‐2‐5 towards Rhodamine B (RhB) reached 2532.3 mg g−1, showing a great potential in cleaning water. As an active electrode material for supercapacitor, the specific capacitance for SPC‐1‐2‐5 reached 296.7 F g−1 at the current density of 0.5 A g−1. And the specific capacitance retained 92.8 % after 10000 cycles at 5 A g−1, also demonstrating its excellent cycle stability in electrochemistry. This methodology of simultaneous activation and confinement could be extended to obtain new carbon materials for various applications.

Correction: An anionic and cationic surfactant-assisted hydrothermal synthesis of cobalt oxide nanoparticles as the active electrode material for supercapacitors

Correction for ‘An anionic and cationic surfactant-assisted hydrothermal synthesis of cobalt oxide nanoparticles as the active electrode material for supercapacitors’ by R. R. Samal et al., New J. Chem., 2021, 45, 2795–2803; DOI: 10.1039/D0NJ05088A.

Gas Altered Hierarchical Porous Graphene Aerogel with High Energy Density

A hierarchical porous graphene aerogel (HP-GA) with hand tearing bread like macro-morphology is achieved through hydrothermal treatment a mix suspension of manganese dioxide (MnO2) and hydrogen chloride (HCl) containing graphite oxide (H-GO) before freeze drying. The chlorine gas (Cl2 as a result of the reaction of HCl and MnO2 is responsible for the formation of the hierarchical porous microstructure and hand tearing bread like macro-morphology. When used as the active electrode material in supercapacitors, the HP-GA exhibits a large specific capacitance of 284 F g-1 at 1 A g-1 and ultrahigh energy density of 10 Wh kg-1 at 250 W kg-1 in aqueous electrolyte. This work provides a versitile, simple and easy-to-controlled way to alter the microstructure and macromorphology of graphene-based areogels that have promissing applications in many areas including adsorption, energy storage, heat insulation, acoustical insulation and intelligent sensing.

An anionic and cationic surfactant-assisted hydrothermal synthesis of cobalt oxide nanoparticles as the active electrode material for supercapacitors

Schematic representation of surfactant action for synthesis of cobalt hydroxide and oxide.

Preparation of hollow mesoporous carbon spheres by pyrolysis-deposition using surfactant as carbon precursor

Hollow mesoporous carbon spheres (HCS) are widely used in many fields, such as supercapacitors, adsorption, separation, batteries, etc., due to their large specific surface area, large cavity, thin mesoporous shell and good chemical stability. Herein, N-doped HCS was prepared using the pyrolysis-deposition method, with cetyltrimethylammonium bromide (CTAB) micelles derived from a hard template of solid silica core coated with mesoporous silica (SiO2@mSiO2), as the carbon and nitrogen precursor. This method realizes direct carbon formation from the decomposable surfactant CTAB, which avoids the need for other carbon precursors and simplifies the preparation process. The mesopores on the SiO2@mSiO2 template shell provide limited space and the transition metals provide active sites, which promotes the deposition of carbon derived from surfactants.The shell thickness of HCS can be adjusted by the thickness of the SiO2@mSiO2 template shell, which leads to a change in the morphology, i.e. from imperfect (macropore) hollow spheres to complete hollow spheres and transformation of the surface from rough to smooth. Ultimately, the resultant HCS completely replicates the morphology of the template and shows a uniform spherical shape with a mesoporous shell, a cavity, a high specific surface area and suitable N-doping content, which ensures good electrochemical performance as an active electrode material in supercapacitors.

Carbon nanotubes aerogels dispersed by thermal excitation on Ni Foam@NiCo2O4 nanoneedles with enhanced properties for supercapacitor

Herein, the method of free arc thermal excitation is developed to disperse CNTs agglomerations to fluffy CNTs aerogels on Ni foam@NiCo2O4 nanoneedles (NF@NiCo2O4/CNTs). NF@NiCo2O4/CNTs is evaluated as an electrode for supercapacitor and shows remarkable electrochemical properties, which is resulted from the synergistic effect of high conductive CNTs aerogels and sufficient active sites of NiCo2O4 nanoneedles. The mass specific capacity and rate capability of NF@NiCo2O4/CNTs are 20% and 14% higher than that of NF@NiCo2O4 due to the high conductivity of CNTs aerogels. The assembled NF@NiCo2O4/CNTs//activated carbon (AC) device exhibites an exellent energy density of 43.2 Wh kg−1 when the power density is 801 W kg−1. The asymmetric device also has a high cycling stability that the energy density can remain 85% after 5000 cycles. More importantly, the new strategy offers an ingratiating strategy to disperse CNTs losslessly, meanwhile provides a new view into the combination of CNTs and various active materials for supercapacitor electrodes.

Synthesis of activated carbon monolith derived from cocoa pods for supercapacitor electrodes application

ABSTRACT Agricultural and agro-industrial residues are ordinary wastes in the forestry industry and their valorization is an important issue.Cocoa (Theobroma cacao) pods waste was chosen as an activated activated carbon material and studied as active materials for supercapacitor electrodes. The carbon electrode has been made using 0.3 M and 0.4 M Potassium Hydroxide (KOH) activators at 700°C. Physical properties were tested by measuring density, X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM), while the electrochemical properties were tested using the Cyclic Voltammetry (CV) method. Activated carbon electrodes were constructed by a combination of chemical activation, and physical activation methods. The technique of making carbon electrodes was started from pre-carbonization, milling, chemical activation, pellet making, carbonization, and physical activation. Analysis of dimensions, density, and specific capacitance in the manufacture of carbon electrodes showed the mass, diameter, thickness, and density of the electrodes decreased with the addition of KOH concentrations from 0.3 M to 0.4 M. While the specific capacitance value of the electrode was directly proportional to the increase of KOH concentration. In XRD measurement data, the values of 2θ in the range of 23.569°–24.747° was obtained for the reflection field 002, and 44.634°–44.781° for the reflection plane 100. X-ray diffraction curve data showed a 0.4 M at 700°C sample having an Lc value and a lattice distance smaller than the sample of 0.3 M at 700°C. Therefore, it could be indicated that the surface area of the sample of 0.4 M at 700°C was greater than the sample of 0.3 M at 700°C. The electrochemical test showed that the method of chemical activation variation of 0.4 M produced electrodes with better performance than 0.3 M. The specific capacitance value obtained at a concentration of 0.3 M was 90.2 F/gr with a density of 0.850 gr/cm3, while at a concentration of 0.4 M was 140.2 F/gr with a density of 0.802 gr/cm3. These results indicate the high potential of agricultural cocoa pods based activated carbon monoliths as supercapacitor electrode.