Boron-doped ordered mesoporous carbons for the application of supercapacitors

Boron-doped three-dimensional porous carbon framework/carbon shell encapsulated silicon composites for high-performance lithium-ion battery anodes

Deleterious volumetric expansion and poor electrical conductivity seriously hinder the application of Si-based anode materials in lithium-ion batteries (LIBs). Herein, boron-doped three-dimensional (3D) porous carbon framework/carbon shell encapsulated silicon (B-3DCF/Si@C) hybrid composites are successfully prepared by two coating and thermal treatment processes. The presence of 3D porous carbon skeleton and carbon shell effectively improves the mechanical properties of the B-3DCF/Si@C electrode during the cycling process, ensures the stability of the electrical contacts of the silicon particles and stabilizes the solid electrolyte interface (SEI) layer, thus enhancing the electronic conductivity and ion migration efficiency of the anode. The developed B-3DCF/Si@C anode has a high reversible capacity, excellent cycling stability and outstanding rate performance. A reversible capacity of 1288.5 mAh/g is maintained after 600 cycles at a current density of 400 mA g-1. The improved electrochemical performance is demonstrated in a full cell using a LiFePO4-based cathode. This study presents a novel approach that not only mitigates the large volume expansion effects in LIB anode materials, but also provides a reference model for the preparation of porous composites with various functionalities.

Surface Engineering of Biochar Toward Simultaneously Generating Superamphiphilicity and Catalytic Activity for Strengthening Pickering Interfacial Catalysis

Multifunctional carbon materials have revealed distinctive features and excellent performance in the field of catalysis. However, the facile fabrication of bifunctional carbon materials with special wettability and catalytic activity remains a grand challenge in Pickering emulsion catalysis. Herein, we reported one-step construction of bifunctional biochar with superamphiphilicity and catalytic activity directly from the thermolysis of sawdust and 1-butyl-3-methylimidazolium tetrafluoroborate for enhancing the oxidation of benzyl alcohol in Pickering emulsion. Co-doping of B and F enhanced the hydrophilicity of biochar, and the oleophilicity of biochar was kept simultaneously. Conversion became 4 times using bifunctional biochar compared with blank results during the oxidation of benzyl alcohol. More interestingly, the turnover frequency (TOF) value using bifunctional biochar enhanced 61 % than that employing N-doped superamphiphilic carbon without catalytic activity. Catalytic activities of bifunctional biochar could be ascribed to the existence of different chemical bonds containing the element B. This work paves a path toward rational design of bifunctional biochar materials with special wettability and catalytic activity for greatly enhancing the liquid-liquid biphasic reaction efficiencies.

A Review of the Preparation of Porous Fibers and Porous Parts by a Novel Micro-Extrusion Foaming Technique

This review introduces an innovative technology termed "Micro-Extrusion Foaming (MEF)", which amalgamates the merits of physical foaming and 3D printing. It presents a groundbreaking approach to producing porous polymer fibers and parts. Conventional methods for creating porous materials often encounter obstacles such as the extensive use of organic solvents, intricate processing, and suboptimal production efficiency. The MEF technique surmounts these challenges by initially saturating a polymer filament with compressed CO2 or N2, followed by cell nucleation and growth during the molten extrusion process. This technology offers manifold advantages, encompassing an adjustable pore size and porosity, environmental friendliness, high processing efficiency, and compatibility with diverse polymer materials. The review meticulously elucidates the principles and fabrication process integral to MEF, encompassing the creation of porous fibers through the elongational behavior of foamed melts and the generation of porous parts through the stacking of foamed melts. Furthermore, the review explores the varied applications of this technology across diverse fields and imparts insights for future directions and challenges. These include augmenting material performance, refining fabrication processes, and broadening the scope of applications. MEF technology holds immense potential in the realm of porous material preparation, heralding noteworthy advancements and innovations in manufacturing and materials science.

B, P, and S heteroatom doped, bio- and hemo-compatible 2D graphitic-carbon nitride (g-C3N4) with antioxidant, light-induced antibacterial, and bioimaging endeavors

The synthesis of two-dimensional (2D) graphiticg-C3N4and heteroatom-doped graphitic H@g-C3N4(H: B, P, or S) particles were successfully done using melamine as source compounds and boric acid, phosphorous red, and sulfur as doping agents. The band gap values of 2Dg-C3N4, B50@g-C3N4, P50@g-C3N4, and S50@g-C3N4structures were determined as 2.90, 3.03, 2.89, and 2.93 eV, respectively. The fluorescent emission wavelengths of 2Dg-C3N4, B50@g-C3N4, P50@g-C3N4, and S50@g-C3N4structures were observed at 442, 430, 441, and 442 nm, respectively upon excitation atλEx= 325 nm. There is also one additional new emission wavelength was found at 345 nm for B50@g-C3N4structure. The blood compatibility test results ofg-C3N4, B50@g-C3N4, P50@g-C3N4, and S50@g-C3N4structures revealed that all materials are blood compatible with <2% hemolysis and >90% blood clotting indices at 100μg ml-1concentration. The cell toxicity of the prepared 2D graphitic structures were also tested on L929 fibroblast cells, and even the heteroatom doped hasg-C3N4structures induce no cytotoxicity was observed with >91% cell viability even at 250μg ml-1particle concentration with the exception of P50@g-C3N4which as >75 viability. Moreover, for 2Dg-C3N4, B50@g-C3N4, and S50@g-C3N4constructs, even at 500μg ml-1concentration, >90% cell viabilities was monitored. As a diagnostic material, B50@g-C3N4was found to have significantly high penetration and distribution abilities into L929 fibroblast cells granting a great potential in fluorescence imaging and bioimaging applications. Furthermore, the elemental doping with B, P, and S ofg-C3N4were found to significantly increase the photodynamic antibacterial activity e.g. more than half of bacterial elimination by heteroatom-doped forms ofg-C3N4under UVA treatment was achieved.

Nanostructured Conducting Polymers and Their Applications in Energy Storage Devices

Due to the energy requirements for various human activities, and the need for a substantial change in the energy matrix, it is important to research and design new materials that allow the availability of appropriate technologies. In this sense, together with proposals that advocate a reduction in the conversion, storage, and feeding of clean energies, such as fuel cells and electrochemical capacitors energy consumption, there is an approach that is based on the development of better applications for and batteries. An alternative to commonly used inorganic materials is conducting polymers (CP). Strategies based on the formation of composite materials and nanostructures allow outstanding performances in electrochemical energy storage devices such as those mentioned. Particularly, the nanostructuring of CP stands out because, in the last two decades, there has been an important evolution in the design of various types of nanostructures, with a strong focus on their synergistic combination with other types of materials. This bibliographic compilation reviews state of the art in this area, with a special focus on how nanostructured CP would contribute to the search for new materials for the development of energy storage devices, based mainly on the morphology they present and on their versatility to be combined with other materials, which allows notable improvements in aspects such as reduction in ionic diffusion trajectories and electronic transport, optimization of spaces for ion penetration, a greater number of electrochemically active sites and better stability in charge/discharge cycles.

DES mediated synthesis of sewage sludge-derived B, N-doped carbons for electrochemical applications

In order to effectively utilize organic matter in sewage sludge (SS), a new porous carbon material was successfully prepared from SS with deep eutectic solvents (DES) (boric acid and urea), in which DES was firstly used to solvent to separate organic matter, also playing the role as a B and N donor as well as acid activator to form porous B, N-carbons. As-synthesized B, N-carbon electrode materials possessed a high specific capacitance of 251.4 F/g at a current density of 1 A/g. It retained 84.28% of the capacitance at an ultrahigh current density of 5 A/g. The energy density was 9.502 Wh/Kg at a power density of 245.4 W/kg in 6 M KOH in symmetric supercapacitor.

Recent Advanced Supercapacitor: A Review of Storage Mechanisms, Electrode Materials, Modification, and Perspectives

In recent years, the development of energy storage devices has received much attention due to the increasing demand for renewable energy. Supercapacitors (SCs) have attracted considerable attention among various energy storage devices due to their high specific capacity, high power density, long cycle life, economic efficiency, environmental friendliness, high safety, and fast charge/discharge rates. SCs are devices that can store large amounts of electrical energy and release it quickly, making them ideal for use in a wide range of applications. They are often used in conjunction with batteries to provide a power boost when needed and can also be used as a standalone power source. They can be used in various potential applications, such as portable equipment, smart electronic systems, electric vehicles, and grid energy storage systems. There are a variety of materials that have been studied for use as SC electrodes, each with its advantages and limitations. The electrode material must have a high surface area to volume ratio to enable high energy storage densities. Additionally, the electrode material must be highly conductive to enable efficient charge transfer. Over the past several years, several novel materials have been developed which can be used to improve the capacitance of the SCs. This article reviews three types of SCs: electrochemical double-layer capacitors (EDLCs), pseudocapacitors, and hybrid supercapacitors, their respective development, energy storage mechanisms, and the latest research progress in material preparation and modification. In addition, it proposes potentially feasible solutions to the problems encountered during the development of supercapacitors and looks forward to the future development direction of SCs.

Hierarchical nanoarchitectonics of ordered mesoporous carbon from lignin for high-performance supercapacitors

The synthesis of ordered mesoporous carbons (OMCs) with hierarchical pore structure is significant for supercapacitor applications as electrode material. In this study, the ordered mesoporous carbons with hierarchical pore structure (HOMC) are synthesized via solvent evaporation induced self-assembly (EISA) method using lignin from walnut shell as carbon precursor and Co²⁺ ion as crosslinking agent, followed by removal of metal by diluted acid and chemical activation with KHCO₃. The prepared HOMC material has a large specific surface area of 2033 m² g^-1 and high pore volume of 1.59 cm³ g^-1, and it shows good electrochemical performance as the electrode of supercapacitor with high specific supercapacitances of 286 and 206 F g^-1 in 6 M KOH aqueous solutions at 0.2 and 20 A g^-1, respectively. The assembled HOMC-based symmetric supercapacitors provides a specific energy density of 13.5 Wh kg^-1 at a high power density of 44.3 kW kg^-1 and keep good cycling stability after 5000 cycle tests. The superior electrochemical performance is ascribed to the long range ordered parallel mesoporous channels, hierarchical porous structure, high specific surface area and appropriate microporous/mesoporous ratio. The materials prepared in this study have the potential to be used in the fields of adsorption, energy storage and capacitance deionization.

Activation-Induced Surface Modulation of Biowaste-Derived Hierarchical Porous Carbon for Supercapacitors

Wheat straw-derived carbon from the Wheatbelt region in Western Australia was subjected to chemical activation in an electrolyte containing either acid or base treatment. The findings showed an increase in electron/hole mobility towards the interfaces due to the presence of different surface functional groups such as C-SO_x -C and S=C in the carbon framework for acid activation. Likewise, the galvanostatic capacitance measured at a current density of 2 mA cm^-2 in a three-electrode configuration for acid-activated wheat straw exhibited 162 F g^-1 , while that for base-activated wheat straw exhibited 106 F g^-1 . An increase of 34.5 % more capacitance was achieved for acid-treated wheat straw. This improvement is attributed to the synergistic effects between surface functional groups and electrolyte ions, as well as the electronic structure of the porous electrode.

Preparation of Boron/Sulfur-Codoped Porous Carbon Derived from Biological Wastes and Its Application in a Supercapacitor

Abundant biomass resources are a good choice for preparing electrode materials for supercapacitors, but developing a versatile and simple synthetic method to convert them into electrode materials remains a challenge. In the present research, our team reports a promising strategy and cost-efficient method to fabricate boron/sulfur-codoped porous carbon from biomass sources, mainly utilizing four biomass materials. Detailed material characterization showed that the samples produced by this approach possess rich B and S doping. Additionally, the original biomass materials treated by activation produce abundant pores. Therefore, owing to the synergetic effect of abundant atomic doping and microporous/mesoporous distribution, the obtained carbon as electrode material manifested excellent specific capacitances of 290 F g⁻¹ at a 0.5 A g⁻¹ current density. Moreover, the specific energy of the prepared samples of the as-assembled symmetric supercapacitor is as high as 16.65 Wh kg⁻¹ in 1 M Na₂SO₄, with a brilliant cyclical performance of only a 2.91% capacitance decay over 10,000 cycles. In addition, it has been verified universally that three other types of bio-wastes can also prepare electrode material using this method. This paper represents a significant attempt to turn waste biomass into treasure while also providing ideas for the design and preparation of supercapacitor electrode materials.

Modification of ordered mesoporous carbon for removal of environmental contaminants from aqueous phase: A review

Contamination of water bodies by potentially toxic elements and organic pollutants has aroused extensive concerns worldwide. Thus it is significant to develop effective adsorbents for removing these contaminants. As a new member of carbonaceous material families (activated carbon, biochar, and graphene), ordered mesoporous carbon (OMC) with larger specific surface area, ordered pore structure, and higher pore volume are being evaluated for their use in contaminant removal. In this paper, modification techniques of OMC were systematically reviewed for the first time. These include nonmetallic doping modification (nitrogen, sulfur, and boron) and the impregnation of nano-metals and metal oxides (iron, copper, cobalt, nickel, magnesium, and rare earth element). Reaction conditions (solution pH, reaction temperature, sorbent dosage, and contact time) are of critical importance for the removal performance of contaminants onto OMC. In addition, the pristine and modified OMC have been investigated for the removal of a range of contaminants, including cationic/anionic toxic elements and organic contaminants (synthetic dye, phenol, and others), and involving different and specific mechanisms of interaction with contaminants. The future research directions of the application of pristine and modified OMC were proposed. Overall, this review can provide sights into the modification techniques of OMC for removal of environmental contaminants.

A Review of the Use of Carbon Nanotubes and Graphene-Based Sensors for the Detection of Aflatoxin M1 Compounds in Milk

This paper presents a comprehensive review of the detection of aflatoxin compounds using carbon allotrope-based sensors. Although aflatoxin M1 and its derivative aflatoxin B1 compounds have been primarily found in milk and other food products, their presence above a threshold concentration causes disastrous health-related anomalies in human beings, such as growth impairment, underweight and even carcinogenic and immunosuppressive effects. Among the many sensors developed to detect the presence of these compounds, the employment of certain carbon allotropes, such as carbon nanotubes (CNTs) and graphene, has been highly preferred due to their enhanced electromechanical properties. These conductive nanomaterials have shown excellent quantitative performance in terms of sensitivity and selectivity for the chosen aflatoxin compounds. This paper elucidates some of the significant examples of the CNTs and graphene-based sensors measuring Aflatoxin M1 (ATM1) and Aflatoxin B1 (AFB1) compounds at low concentrations. The fabrication technique and performance of each of the sensors are shown here, as well as some of the challenges existing with the current sensors.

Construction and Theoretical Calculation of an Ultra-High-Performance LiVPO4F/C Cathode by B-Doped Pyrolytic Carbon from Poly(vinylidene Fluoride)

B-doped pyrolytic carbon from poly(vinylidene fluoride) (PVDF) was used to enhance the performance of a LiVPO₄F/C cathode, which is much cheaper than carbon nanotubes and graphene. The carbon layer in LVPF/C-B₃ becomes more and more regular compared with the undoped sample. The electronic conductivity, diffusion coefficient, and rate and cycle performance of the B-doped cathode are greatly improved. The capacities of LVPF/C-B₃ at 0.2C, 5C, and 15C are 148.1, 132.9, and 125.6 mAh·g^-1, which may be the best reported magnitude. The crystallite structure of LiVPO₄F/C is well maintained after 300 charge and discharge cycles. The carbonization process of PVDF is greatly accelerated. These improvements are attributed to the changes in chemical and electronic structures. The generation of BC₂O and BCO₂ results in many defective active sites, and BC₃ promotes the growth of a six-membered carbon ring. According to the first-principles approach based on density functional theory, the state density around the Fermi level of the B-doped pyrolytic carbon is increased. The electronic structure of pyrolytic carbon is transformed from a P-type semiconductor to a metal-like structure through the generation of pyridinic-like and graphitic-like B. Therefore, the electronic conductivity of LiVPO₄F/C is increased.

Doping strategy, properties and application of heteroatom-doped ordered mesoporous carbon

To date, tremendous achievements have been made to produce ordered mesoporous carbon (OMC) with well-designed and controllable porous structure for catalysis, energy storage and conversion. However, OMC as electrode material suffers from poor hydrophilicity and weak electrical conductivity. Numerous attempts and much research interest have been devoted to dope different heteroatoms in OMC as the structure defects to enhance its performance, such as nitrogen, phosphorus, sulphur, boron, and multi heteroatoms. Unfortunately, the "how-why-what" question for the heteroatom-doped OMC has not been summarized in any published reports. Therefore, this review focuses on the functionalization strategies of heteroatoms in OMC and the corresponding process characteristics, including in situ method, post treatment method, and chemical vapor deposition. The fundamentally influencing mechanisms of various heteroatoms in electrochemical property and porous structure are summarized in detail. Furthermore, this review provides an updated summary about the applications of different heteroatom-doped OMC in supercapacitor, electrocatalysis, and ion battery during the last decade. Finally, the future challenges and research strategies for heteroatom-doped OMC are also proposed.

Enhancement of Pb (II) adsorption by boron doped ordered mesoporous carbon: Isotherm and kinetics modeling

Boron doped ordered mesoporous carbon (BMC) was prepared to improve the adsorption of Pb(II). The effects of several parameters such as contact time, pH, and ionic strength on the adsorption by both pristine ordered mesoporous carbon (OMC) and BMC were investigated. Thermodynamic, sorption isotherm and adsorption kinetics models were used to study the adsorption mechanisms by each of the adsorbents. Based on intraparticle diffusion model, the adsorption process by the two adsorbents mainly involved the quick liquid-film diffusion stage and slow pore diffusion portion, and fitting experimental data with Temkin model indicates that the adsorption process by both of the adsorbents involve physisorption and chemisorption. Based on Langmuir model, the estimated maximum adsorption capacity for BMC was about 1.3 times higher than the pristine OMC. Moreover, BMC retained good adsorption performance in tap and lake water, and could be regenerated effectively and recycled using EDTA. The results suggested that BMC, with enhanced adsorption performance compared with OMC, could be considered as very effective and promising materials for Pb (II) removal from wastewater.

Studies on Possible Ion-Confinement in Nanopore for Enhanced Supercapacitor Performance in 4V EMIBF4 Ionic Liquids

Supercapacitors have the rapid charge/discharge kinetics and long stability in comparison with various batteries yet undergo low energy density. Theoretically, square dependence of energy density upon voltage reveals a fruitful but challenging engineering tenet to address this long-standing problem by keeping a large voltage window in the compositionally/structurally fine-tuned electrode/electrolyte systems. Inspired by this, a facile salt-templating enables hierarchically porous biochars for supercapacitors filled by the high-voltage ionic liquids (ILs). Resultant nanostructures possess a coherent/interpenetrated framework of curved atom-thick sidewalls of 0.8-/1.5-nanometer pores to reconcile the pore-size-dependent adlayer structures of ILs in nanopores. Surprisingly, this narrow dual-model pore matches ionic radii of selected ILs to accommodate ions by unique coupled nano-/bi-layer nanoconfinements, augmenting the degree of confinement (DoC). The high DoC efficiently undermines the coulombic ordering networks and induces the local conformational oscillations, thus triggering an anomalous but robust charge separation. This novel bi-/mono-layer nanoconfinement combination mediates harmful overscreening/overcrowding effects to reinforce ion-partitioning, mitigating long-lasting conflicts of power/energy densities. This interesting result differs from a long-held viewpoint regarding the sieving effect that ion-in-pore capacitance peaks only if pore size critically approaches the ion dimension. Optimal biocarbon finally presents a very high/stable operational voltage up to 4 V and specific energy/power rating (88.3 Whkg^-1 at 1 kWkg^-1, 47.7 Whkg^-1 albeit at a high battery-accessible specific power density of 20 kWkg^-1), overwhelmingly outperforming most hitherto-reported supercapacitors and some batteries. Such attractive charge storage level can preliminarily elucidate an alternative form of a super-ionic-state high-energy storage linked with both the coordination number and coulombic periodism of the few ion-sized mesopores inside carbon electrodes, escalating supercapacitors into a novel criterion of charge delivery.

(Co, Mn)-Doped NiSe2-diethylenetriamine (dien) nanosheets and (Co, Mn, Sn)-doped NiSe2 nanowires for high performance supercapacitors: compositional/morphological evolution and (Co, Mn)-induced electron transfer

A series of MSe2-dien (M = metal(ii) ion and dien = diethylenetriamine) were grown on Ni foam (NF) based on Co(ii)/Mn(ii) salts with different molar ratios. It was found that the Co-free sample exhibited hollow tubes built by numerous interconnected nanowires, whereas nanosheets were observed in the Co-involved samples. The formation of nanosheets is associated with Co(ii), which is due to the fact that Co(ii) promotes the metal selenide nanosheet to grow along its (011[combining macron]) facet (thickness direction). Furthermore, the formation and compositional/morphological evolution of the samples were investigated. Among them, (Co, Mn)-NiSe2-dien/NF (2 : 1-Co/Mn sample) showed the largest specific capacity of 288.6 mA h g-1 at 1 A g-1 with a retention of 69% at 10 A g-1 (198.6 mA h g-1), which is associated with its ultrathin nanosheet arrays and the co-doping of (Co, Mn) into NiSe2-dien, leading to the redistribution of electron densities around the Ni and Se centers. XPS and density functional theory (DFT) calculations proved the electron transfer from NiSe2-dien to the adsorbed OH- ions from the electrolyte solution, which can facilitate the redox reaction between active sites and electrolyte ions to enhance the electrochemical performance. A hybrid supercapacitor, (Co, Mn)-NiSe2-dien/NF//activated carbon, was fabricated, which displayed an energy density of 50.9 W h kg-1 at a power density of 447.3 W kg-1 and good cycling stability with 84% capacity retention after 10 000 charge-discharge cycles. Furthermore, (Co, Mn)-doped NiSe2-dien nanosheets could be transformed into (Co, Mn, Sn)-doped NiSe2 nanowire arrays after immersion in SnCl2 alcoholic solution due to cation exchange and the Kirkendall effect, and the obtained sample exhibited a decent areal capacity of 0.267 mA h cm-2 at 5 mA cm-2.

Boron/nitrogen co-doped carbon synthesized from waterborne polyurethane and graphene oxide composite for supercapacitors

We report B/N co-doped carbon materials synthesized by an efficient and easy one-step carbonization method with ferric catalyst treatment from a precursor with boric acid treatment after the formation of the composite between waterborne polyurethane (WPU) and graphene oxide (GO). The nitrogen content was improved with the introduction of numerous melamine in the synthetic process of WPU. In addition, WPU possessed a repetitive basic unit urethane bond (–NHCOO); thus, nitrogen heteroatom could be efficiently introduced into the WPU/GO composite from WPU as a nitrogen-rich carbon. In addition, the specific surface area was increased by the boric acid treatment and washing process. The ferric catalyst treatment could prevent the formation of inert B–N bonds. Thus, the synthesized B/N co-doped carbon materials exhibited high specific capacitance (330 F g⁻¹ at 0.5 A g⁻¹), superior rate performance, and excellent cycling stability. Furthermore, the assembled symmetric supercapacitor displayed a good energy density (7.9 W h kg⁻¹ at 505 W kg⁻¹) and a good capacitance retention of about 89.9% after 5000 charge–discharge cycles in 6 M KOH electrolyte. Therefore, the as-prepared B/N co-doped carbon materials show a promising future in supercapacitor application.

We report B/N co-doped carbon materials synthesized by a carbonization method with ferric catalyst treatment from a precursor with boric acid treatment after the formation of the composite between waterborne polyurethane and graphene oxide.

Preparation of boron-doped mesoporous carbon with aromatic compounds as expanding agents

Boron-doped ordered mesoporous carbon (B-OMC) was synthesized using the aromatic compounds benzene, 1,3,5-trimethylbenzene, 1,3,5-triethylbenzene and 1,3,5-triisopropylbenzene as expanding agents. The expanding mechanism as well as the effect of the expanding agent molecule on the properties of B-OMCs were studied. Compared with the unmodified one, the order of B-OMCs treated with aromatic compounds is improved significantly. In addition, along with the increase in hydrophobicity and steric hindrance of the expanding agents, the pore size and pore volume of B-OMCs increase, while their surface area and specific capacitance increase first, and then drop off slightly. The obtained B-OMC-TEB has a high boron content (1.54 wt%), the largest surface area (693 m2 g-1), a much better electrochemical performance and the highest specific capacitance (290 F g-1), 30% higher than that of ordinary B-OMC. Furthermore, the specific capacitance can be maintained at 155 F g-1 even at a high current density of 20 A g-1, indicating that it has a high capacitance retention rate.

Graphene and activated carbon-wrapped and Co3O4-intercalated 3D sandwich nanostructure hybrid for high-performance supercapacitance

The graphene/Co₃O₄/activated carbon (GCA) 1 : 9 capacitor shows the best electrochemical properties with Co₃O₄ particles that were homogeneously dispersed between the graphene/Co₃O₄ (GC) layers.

Fabrication of sponge-like α-Ni(OH)2 on styrene–acrylonitrile copolymer (SAN)-derived carbon spheres as electrode materials for supercapacitor application

Styrene–acrylonitrile copolymer particles (SANPs) were synthesized through dispersion polymerization.