High-Surface-Area Nitrogen-Doped Reduced Graphene Oxide for Electric Double-Layer Capacitors

Interfacial Insights into the Polarization Protocol: Toward Reducing Corrosion and Improving the Cycle Life of Electrochemical Capacitors

The number of scientific publications on the impact of corrosion on current collectors on the working parameters of electrochemical capacitors is very limited. The aim of current research is to search for new, environmentally friendly chemical power sources and energy storage devices and to improve existing ones. Therefore, this article presents a simple and effective way to improve the life of a symmetric electrochemical capacitor by changing the direction of electrode polarization, which in turn inhibits the corrosion of the current collector. This slows the degradation of current collectors of positive electrode over long durations. However, activated carbon electrode corrosion also occurs. Experiments on capacitors with stainless steel and gold current collectors indicate that the lifespan of the latter is much longer than that of the former. Therefore, current collector corrosion has a distinct and detrimental impact on electrochemical capacitor operation. Moreover, the research results indicate that carbon corrosion results from current collector corrosive damage.

Redox-Active Phenanthrenequinone Molecules and Nitrogen-Doped Reduced Graphene Oxide as Active Material Composites for Supercapacitor Applications

Carbon-based supercapacitor electrodes are generally restricted in energy density, as they rely exclusively on electric double-layer capacitance (EDLC). The introduction of redox-active organic molecules to obtain pseudocapacitance is a promising route to develop electrode materials with improved energy densities. In this work, we develop a porous nitrogen-doped reduced graphene oxide and 9,10-phenanthrenequinone composite (N-HtrGO/PQ) via a facile one-step physical adsorption method. The electrochemical evaluation of N-HtrGO/PQ using cyclic voltammetry showed a high capacitance of 605 F g-1 in 1 M H2SO4 when the composite consisted of 30% 9,10-phenanthrenequinone and 70% N-HtrGO. The measured capacitance significantly exceeded pure N-HtrGO without the addition of redox-active molecules (257 F g-1). In addition to promising capacitance, the N-HtrGO/30PQ composite showed a capacitance retention of 94.9% following 20,000 charge/discharge cycles. Based on Fourier transform infrared spectroscopy, we postulate that the strong π-π interaction between PQ molecules and the N-HtrGO substrate enhances the specific capacitance of the composite by shortening pathways for electron transfer while improving structural stability.

Efficient photocatalytic bactericidal performance of green-synthesised TiO2/reduced graphene oxide using banana peel extracts

In this study, the fabrication of titanium dioxide/reduced graphene oxide (TiO2/rGO) utilising banana peel extracts (Musa paradisiaca L.) as a reducing agent for the photoinactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was explored. The GO synthesis was conducted using a modified Tour method, whereas the production of rGO involved banana peel extracts through a reflux method. The integration of TiO2 into rGO was achieved via a hydrothermal process. The successful synthesis of TiO2/rGO was verified through various analytical techniques, including X-ray diffraction (XRD), gas sorption analysis (GSA), Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), scanning electron microscope-energy dispersive X-ray (SEM-EDX) and transmission electron microscopy (TEM) analyses. The results indicated that the hydrothermal-assisted green synthesis effectively produced TiO2/rGO with a particle size of 60.5 nm. Compared with pure TiO2, TiO2/rGO demonstrated a reduced crystallite size (88.505 nm) and an enhanced surface area (22.664 m2/g). Moreover, TiO2/rGO featured a low direct bandgap energy (3.052 eV), leading to elevated electrical conductivity and superior photoconductivity. To evaluate the biological efficacy of TiO2/rGO, photoinactivation experiments targeting E. coli and S. aureus were conducted using the disc method. Sunlight irradiation emerged as the most effective catalyst, achieving optimal inactivation results within 6 and 4 h.

Efficient activation of peroxodisulfate by novel bionic iron-encapsulated biochar: The key roles of electron transfer pathway and reactive oxygen species evolution

In this study, a novel iron-encapsulated biochar (Fe@BC) was prepared using the biomass cultivated with an iron-containing solution. The iron in Fe@BC showed the phase change from Fe₃O₄ to α-Fe, and to CFe_15.1, with the increase of pyrolysis temperature (500-900 °C), and a graphene shell formed on the surface of Fe@BC. In addition, the signals assigned to the π-π* shake up, pyridinic N, graphitic N, and defects of Fe@BC were found to be stronger as the pyrolysis temperature increased. The F4@B9 sample, which was prepared at 900 °C, exhibited an excellent performance (98.01 %) to activate peroxydisulfate (PDS) for the degradation of 2,4-dichlorophenol. Electron paramagnetic resonanceand chemical quenching experiments revealed that reactive oxygen radicals (ROS) including sulfate radical (•SO₄^-), hydroxyl radical (•OH), superoxide radical (•O₂^-), and singlet oxygen (¹O₂) existed in the F4@B9/PDS system. Furthermore, the micro-electrolysis process facilitated the generation of •O₂^- (12.35 %) and ¹O₂ (6.49 %) compared with the pure PDS system. Density functional theory revealed that, for the F4@B9-activated PDS process, the graphene shell of F4@B9 served as catalytic active sites as well. According to the correlation analysis, the iron specie of CFe_15.1 was more favorable for the generation of ROS than α-Fe. Also, π-π* shake up, pyridinic N, graphitic N, and defects participated in the PDS activation. This study provides a new method for the preparation of high-performance catalysts from naturally grown biomass with high iron contents.

Activation of Ibuprofen via Ultrasonic Complexation with Silver in N-Doped Oxidized Graphene Nanoparticles for Microwave Chemotherapy of Cervix Tumor Tissues

An ultrasonic method (20 kHz) is introduced to activate pristine ibuprofen organic molecular crystals via complexation with silver in nitrogen-doped oxidized graphene nanoplatforms (∼50 nm). Ultrasonic complexation occurs in a single-step procedure through the binding of the carboxylic groups with Ag and H-bond formation, involving noncovalent π_C=C → π_C=C* transitions in the altered phenyl ring and π_PY → π_CO* in ibuprofen occurring between the phenyl ring and C-O bonds as a result of interaction with hydroxyl radicals. The ibuprofen-silver complex in ≪NrGO≫ exhibits a ∼42 times higher acceleration rate than free ibuprofen of the charge transfer between hexacyanoferrate and thiosulfate ions. The increased acceleration rate can be caused by electron injection/ejection at the interface of the ≪Ag-NrGO≫ nanoplatform and formation of intermediate species (Fe(CN)₅(CNSO₃)^x- with x = 4 or 5 and AgHS₂O₃) at the excess of produced H⁺ ions. Important for microwave chemotherapy, ibuprofen-silver complexes in the ≪NrGO≫ nanoplatform can produce H⁺ ions at ∼12.5 times higher rate at the applied voltage range from 0.53 to 0.60 V. ≪Ibu-Ag-NrGO≫ NPs develop ∼10⁵ order higher changes of the electric field strength intensity than free ibuprofen in the microwave absorption range of 100-1000 MHz as revealed from the theoretical modeling of a cervix tumor tissue.

Discriminating active sites for the electrochemical synthesis of H2O2 by molecular functionalisation of carbon nanotubes

The electrochemical production of H₂O₂via the two-electron oxygen reduction reaction (2e^- ORR) has recently attracted attention as a promising alternative to the current anthraquinone process. Identification of active sites in O-doped carbon materials, which exhibit high activities and selectivities for the 2e^- ORR, is important for understanding the selective electrocatalytic process and achieving the rational design of active electrocatalysts. However, this is impeded by the heterogeneous distribution of various active sites on these catalysts. In this study, we exploited the molecular functionalisation approach to implant anthraquinone, benzoic acid, and phenol groups on carbon nanotubes and systematically compared the electrocatalytic activities and selectivities of these functional groups. Among these oxygen functional groups, the anthraquinone group showed the highest surface-area-normalised and active-site-normalised activities.

Applications of Pristine and Functionalized Carbon Nanotubes, Graphene, and Graphene Nanoribbons in Biomedicine

This review is dedicated to a comprehensive description of the latest achievements in the chemical functionalization routes and applications of carbon nanomaterials (CNMs), such as carbon nanotubes, graphene, and graphene nanoribbons. The review starts from the description of noncovalent and covalent exohedral modification approaches, as well as an endohedral functionalization method. After that, the methods to improve the functionalities of CNMs are highlighted. These methods include the functionalization for improving the hydrophilicity, biocompatibility, blood circulation time and tumor accumulation, and the cellular uptake and selectivity. The main part of this review includes the description of the applications of functionalized CNMs in bioimaging, drug delivery, and biosensors. Then, the toxicity studies of CNMs are highlighted. Finally, the further directions of the development of the field are presented.

Quick in situ generation of a quinone-enriched surface of N-doped carbon cloth electrodes for electric double-layer capacitors

Although carbon-based electric double-layer capacitors (EDLCs) have been put into practical use, their performance needs to be improved by tuning the surface features and structures of the carbon electrodes. In this study, a method of electro-oxidation was developed to engineer the surface features of the carbon cloth wrapped with a nitrogen-doped carbon layer, and then to obtain a highly hydrophilic, nitrogen-doped carbon cloth electrode with plenty of quinone-containing sites. When the obtained materials were used as electrodes in symmetric capacitors, a high area-specific capacitance (1600 mF cm-2 at 1 mA cm-2), high volume energy density (9.47 mW h cm-3), and excellent cycling stability performance (the capacitance only drops by 3% after 10 000 cycles) can be achieved. These results show that the newly developed method is an efficient approach for improving the electrochemical performance of three-dimensional carbon electrodes in EDLCs.

Synthesis, microstructure, multifunctional properties of mayenite Ca12Al14O33 (C12A7) cement and graphene oxide (GO) composites

The Pristine Mayenite Ca12Al14O33 (C12A7) Cement was simply synthesized by using solid-state reaction. The C12A7 and Graphene Oxide (GO) composites (C12A7_GO-x) with various contents of the GO suspension loading (x = 0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt%) were directly prepared by mixing the C12A7 and GO. X-ray diffraction results of pristine C12A7 and all C12A7_GO composites indicated a pure phase corresponding to the standard of C12A7 cement. Raman spectroscopy confirmed the existence of GO in all C12A7_GO samples. Scanning Electron Microscopy (SEM) showed the micrometer grain sizes and the occurrence of grain boundary interfaces for GO incorporation in all C12A7_GO samples. UV-Vis spectroscopy revealed the absorption value of all C12A7_GO samples and red shift near longer wavelengths when increasing the GO concentrations. The dielectric constant of C12A7_GO composites can be explained by the high density of free electron charges for the interfacial polarization on the GO surface. The maximum specific capacitance of C12A7_GO-4 electrode of 21.514 at a current density of 0.2 A g-1 can be attributed to the increase in the electrochemically active surface area for the formation of the electrical double layer capacitors behavior and the effects of high surface area GO connections. Also, the mechanical properties exhibited an increase in Vickers indenter hardness (HV) values with increasing GO contents. The highest HV value was 117.8 HV/2 kg at the C12A7_GO-4 sample. These results showed that the composite materials of the pristine C12A7 cement with GO were highly efficient. All in all, the GO material contained a high potential for enhancing low-cost cement materials in multifunctional properties such as optical, dielectric, electrochemical, and mechanical properties.

Quantum capacitance tuned flexible supercapacitor by UV-ozone treated defect engineered reduced graphene oxide forest

A forest like 3D carbon structure formed by reduced graphene oxide (RGO) was prepared to use as an electrode material for a highly power efficient supercapacitor. To improve the specific energy of the electrode, pore like defects were incorporated on the RGO forests by atomic oxygen etching, during the UV-ozone treatment. The modified surface helps to increase the net capacitance by permitting the electrolyte to the inner core of the active material and improving the minimal quantum capacitance. Density functional theory based first principle studies were carried out to find DOS at the Fermi level of defect induced RGO sheet and hence to validate the effect of quantum capacitance on net capacitance. Specific capacitance of RGO forest was increased by almost 150% after introduction of the defects. The best performing material exhibits 18.87 mF cm^-2 areal capacitance at 2 mA cm^-2 current density which is equivalent to 70 F cm^-3 at 3.7 A cm^-3 current density, and it was used to fabricate the supercapacitor. Two supercapacitors were fabricated, (i) on graphite sheet (non-flexible) and (ii) on scotch tape (flexible). Here PVA-KOH gel soaked filter paper was used as electrolyte-separator. Both the prepared supercapacitors on graphite sheet and scotch tape are able to transfer electrical energy with ultra high specific power (656.25 mW cm^-3 and 164.06 mW cm^-3 respectively) while maintaining moderate energy densities. The first device can withstand its primary capacitance by 90% even after 10 K charge-discharge cycles and the flexible device was able to hold 96% of its capacitance after 1 K bending cycles.

Effect of Doping Temperatures and Nitrogen Precursors on the Physicochemical, Optical, and Electrical Conductivity Properties of Nitrogen-Doped Reduced Graphene Oxide

The greatest challenge in graphene-based material synthesis is achieving large surface area of high conductivity. Thus, tuning physico-electrochemical properties of these materials is of paramount importance. An even greater problem is to obtain a desired dopant configuration which allows control over device sensitivity and enhanced reproducibility. In this work, substitutional doping of graphene oxide (GO) with nitrogen atoms to induce lattice–structural modification of GO resulted in nitrogen-doped reduced graphene oxide (N-rGO). The effect of doping temperatures and various nitrogen precursors on the physicochemical, optical, and conductivity properties of N-rGO is hereby reported. This was achieved by thermal treating GO with different nitrogen precursors at various doping temperatures. The lowest doping temperature (600 °C) resulted in less thermally stable N-rGO, yet with higher porosity, while the highest doping temperature (800 °C) produced the opposite results. The choice of nitrogen precursors had a significant impact on the atomic percentage of nitrogen in N-rGO. Nitrogen-rich precursor, 4-nitro-ο-phenylenediamine, provided N-rGO with favorable physicochemical properties (larger surface area of 154.02 m² g⁻¹) with an enhanced electrical conductivity (0.133 S cm⁻¹) property, making it more useful in energy storage devices. Thus, by adjusting the doping temperatures and nitrogen precursors, one can tailor various properties of N-rGO.

One-Step Synthesis of a Nanosized Cubic Li2TiO3-Coated Br, C, and N Co-Doped Li4Ti5O12 Anode Material for Stable High-Rate Lithium-Ion Batteries

Nanosized Li₄Ti₅O₁₂ with both a Li₂TiO₃ coating and C-N-Br co-doping (CLLTO) was successfully synthesized via a facile reverse microemulsion method in one step using hexadecyl trimethyl ammonium bromide as a surface control agent and as a carbon, nitrogen, and bromine source. A uniform Li₂TiO₃ layer was formed on the surface and strongly adhered to the host material Li₄Ti₅O₁₂ (LTO), which played an important role in improving the cyclic stability of CLLTO. The thin and stable Li₂TiO₃ layer has the same cubic structure as LTO, which provides many three-dimensional channels for ion transport. C, N, and Br co-doping in CLLTO promoted the transition of Ti⁴⁺ to Ti³⁺ in Li₄Ti₅O₁₂, which could improve the capacity and facilitate the Li⁺ ion and electron transfer at the interface. The conductive behavior induced by co-doping was estimated by UV-vis diffuse reflectance spectra and further supported by theoretical calculations. The electrical conductivity of both p-type and n-type LTO can be well improved by co-doping C, N, and Br. This improvement may be due to the band gap reduction and the increased n-type electronic modification of the entire LTO. Owing to the synergistic effect of coating, co-doping, and nanosizing at one time, the CLLTO exhibits a high discharge capacity of 177.3-153.9 mA h g^-1 at the working rate of 0.1C-20C, with a capacity retention of 86%. The stable cycling of CLLTO is also obtained after 500 cycles at 20C, with a capacity retention of 95.5% (approximately 8 times higher than that of pure LTO) and almost 100% Coulombic efficiency. With high capacity, excellent rate performance, and good cycling stability, CLLTO can be applied in high-power lithium-ion batteries.

Three-Dimensional Hierarchically Porous Graphene Fiber-Shaped Supercapacitors with High Specific Capacitance and Rate Capability

Chemically converted graphene fiber-shaped supercapacitors (FSSCs) are highly promising flexible energy storage devices for wearable electronics. However, the ultralow specific capacitance and poor rate performance severely hamper their practical applications. They are caused by severe stacking of graphene nanosheets and tortuous ion diffusion path in graphene-based electrodes; thus, the ultralow utilization of graphene has been rarely carefully considered to date. Here, we address these issues by developing three-dimensional hierarchically porous graphene fiber with the incorporation of holey graphene for efficient utilization of graphene to achieve fast charge diffusion and good charge storage capability. Without deterioration in electrical but robust mechanical properties, the optimal graphene fiber shows ultrahigh specific capacitance of 220.1 F cm^-3 at current density of 0.1 A cm^-3 and boosted specific capacitance of 254.3 F cm^-3 at 0.1 A cm^-3 after nitrogen doping. Moreover, the nitrogen-doped 40% holey graphene hybrid fiber-assembled FSSC exhibits ultrahigh rate capability (96, 91, and 87% at current density of 0.5, 1.0, and 2.0 A cm^-3, respectively, and 67% even at ultrahigh current density of 10.0 A cm^-3) and excellent cycle stability (95.65% capacitance retention after 10 000 cycles). The contribution of three-dimensional interconnected hierarchically porous network to the enhanced electrochemical (EC) performance is semiquantitatively elucidated by Brunauer-Emmett-Teller and energy dispersive spectroscopy mapping. Our work gives insights into the importance of fully utilizing graphene and provides an efficient strategy for high EC performance in chemically converted graphene-based FSSCs.

Insights into Heteroatom-Doped Graphene for Catalytic Ozonation: Active Centers, Reactive Oxygen Species Evolution, and Catalytic Mechanism

To guide the design of novel graphene-based catalysts in catalytic ozonation for micropollutant degradation, the mechanism of catalytic ozonation with heteroatom-doped graphene was clarified. Reduced graphene oxide doped with nitrogen, phosphorus, boron, and sulfur atoms (N-, P-, B-, and S-rGO) were synthesized, and their catalytic ozonation performances were evaluated in the degradation of refractory organics and bromate elimination simultaneously. Doping with heteroatoms, except sulfur, significantly improved the catalytic ozonation activity of graphene. Introducing sulfur atoms destroyed the stability of graphene during ozonation, with the observed partial performance improvement caused by surface adsorption. Degradation pathways for selected refractory organics were proposed based on the intermediates identified using high-resolution Orbitrap mass spectroscopy and gas chromatographic-mass spectroscopy. Three and six new unopened intermediates were identified in benzotriazole and p-chlorobenzoic acid degradation, respectively. Roles of chemical functional groups, doped atoms, free electron, and delocalized π electron of heteroatom-doped graphene in catalytic ozonation were identified, and contributions of these active centers to the formation of reactive oxygen species (ROS), including hydroxyl radicals, superoxide radicals, singlet oxygen, and H₂O₂, were evaluated. A mechanism for catalytic ozonation by heteroatom-doped graphene was proposed for the first time.

Undiscovered Mechanism for Pyrogenic Carbonaceous Matter-Mediated Abiotic Transformation of Azo Dyes by Sulfide

Pyrogenic carbonaceous matter (PCM) catalyzes the transformation of a range of organic pollutants by sulfide in water; however, the mediation mechanisms are not fully understood. In this study, we observed for the first time that the degradation of azo dyes by sulfide initially underwent a lag phase followed by a fast degradation phase. Interestingly, the presence of PCM only reduced the lag phase length of the azo dye decolorization but did not significantly enhance the reaction rate in the fast degradation phase. An analysis of the azo dye reduction and polysulfide formation indicated that PCM facilitated the transformation of sulfide into polysulfides, including disulfide and trisulfide, resulting in fast azo dye reduction. Moreover, the oxygen functional groups of the PCM, especially the quinones, may play an important role in the transformation of sulfide into polysulfides by accelerating the electron transfer. The results of this study provide a better understanding of the PCM-mediated abiotic transformation of organic pollutants by sulfide in anaerobic aqueous environments.

Graphene from discharged dry cell battery electrodes

Utilization of extracted graphite rods from discharged dry cell batteries for synthesis of graphene oxide / graphene serves two purposes, one is waste management which supports environmental safety and the second is low cost production of graphene oxide / graphene which are highly promising 2D materials in various fields of research. In the present work, a sustainable feasibility for the synthesis of graphene oxide / graphene from graphite rods of waste dry cell batteries is demonstrated. The graphite rods separated from the waste dry cell batteries were subjected to electrochemical exfoliation (ECE) in an acidic media. The graphene oxide (GO) obtained from this method was subjected to reduction heat treatment under argon atmosphere at suitable temperature and time period. Finally, the reduced graphene oxide (rGO) i.e., graphene was characterized using XRD, FTIR, Raman Spectroscopy, TGA, BET, SEM and TEM. The few layer graphene structure is supposed to be less defective in comparison to similar exfoliation techniques due to less oxygen-functional groups associated with the intermediate graphene oxide.

Advanced Energy Storage Devices: Basic Principles, Analytical Methods, and Rational Materials Design

Tremendous efforts have been dedicated into the development of high-performance energy storage devices with nanoscale design and hybrid approaches. The boundary between the electrochemical capacitors and batteries becomes less distinctive. The same material may display capacitive or battery-like behavior depending on the electrode design and the charge storage guest ions. Therefore, the underlying mechanisms and the electrochemical processes occurring upon charge storage may be confusing for researchers who are new to the field as well as some of the chemists and material scientists already in the field. This review provides fundamentals of the similarities and differences between electrochemical capacitors and batteries from kinetic and material point of view. Basic techniques and analysis methods to distinguish the capacitive and battery-like behavior are discussed. Furthermore, guidelines for material selection, the state-of-the-art materials, and the electrode design rules to advanced electrode are proposed.

Kinetic-Dominated Charging Mechanism within Representative Aqueous Electrolyte-based Electric Double-Layer Capacitors

The chemical nature of electrolytes has been demonstrated to play a pivotal role in the charge storage of electric double-layer capacitors (EDLCs), whereas primary mechanisms are still partially resolved but controversial. In this work, a systematic exploration into EDL structures and kinetics of representative aqueous electrolytes is performed with numerical simulation and experimental research. Unusually, a novel charging mechanism exclusively predominated by kinetics is recognized, going beyond traditional views of manipulating capacitances preferentially via interfacial structural variations. Specifically, strikingly distinctive EDL structures stimulated by diverse ion sizes, valences, and mixtures manifest a virtually identical EDL capacitance, where the dielectric nature of solvents attenuates ionic effects on electrolyte redistributions, in stark contradiction with solvent-free counterpart and traditional Helmholtz theory. Meanwhile, corresponding kinetics evolve conspicuously with ionic species, intimately correlated with ion-solvent interactions. The achieved mechanisms are subsequently illuminated by electrochemical measurements, highlighting the crucial interplay between ions and solvents in regulating EDLC performances.

Reduced graphene oxide as a stable and high-capacity cathode material for Na-ion batteries

We report the feasibility of using reduced graphene oxide (RGO) as a cost-effective and high performance cathode material for sodium-ion batteries (SIBs). Graphene oxide is synthesized by a modified Hummers’ method and reduced using a solid-state microwave irradiation method. The RGO electrode delivers an exceptionally stable discharge capacity of 240 mAh g⁻¹ with a stable long cycling up to 1000 cycles. A discharge capacity of 134 mAh g⁻¹ is obtained at a high current density of 600 mA g⁻¹, and the electrode recovers a capacity of 230 mAh g⁻¹ when the current density is reset to 15 mA g⁻¹ after deep cycling, thus demonstrating the excellent stability of the electrode with sodium de/intercalation. The successful use of the RGO electrode demonstrated in this study is expected to facilitate the emergence of low-cost and sustainable carbon-based materials for SIB cathode applications.

Fabrication of Laser-reduced Graphene Oxide in Liquid Nitrogen Environment

Porous structure of reduced graphene oxide (rGO) plays an important role in developing flexible graphene-based devices. In this work, we report a novel methodology for reduction of freestanding graphite oxide (GO) sheet by picosecond pulse laser direct writing in liquid nitrogen. Non-agglomerate and porous structure of rGO is fabricated successfully due to frozen effect during laser processing. Compared with laser-irradiated rGO developed in N₂ gas at ambient environment, the frozen rGO developed in liquid N₂ shows better ordered structure with less defects, crack-free morphology as well as better electron supercapacitor performance including 50–60 Ω/sq in sheet electrical resistance. Mechanism of cryotemperature photoreduction GO is also discussed.

Contact angle measurements: a preliminary diagnostic tool for evaluating the performance of ZnFe2O4 nano-flake based supercapacitors

The contact angle of an electrolyte in contact with an electrode is used as an empirical diagnostic tool to pre-evaluate the performance of a supercapacitor prior to the actual fabrication of the device.