Electrochemical Capacitors Research Articles

Multicrystalline, Highly Oriented Thick‐Film Silicon from Reduction of Soda‐Lime Glass

AbstractThe study describes synthesis and characterization of > 10 µm thick multicrystalline (mc), highly oriented, p‐doped silicon layers by aluminothermic reduction of low‐cost soda‐lime glass. X‐ray diffraction shows a highly preferred (111)‐orientation and excellent crystallinity. Low compressive stress and very good crystallinity are confirmed by the peak position and width of the Raman LO‐phonon line, approaching the one of bulk single‐crystalline wafer material. Due to strong bonding to the glass substrate layer, spalling is not observed. A conductive aluminum‐rich oxide layer is formed underneath the silicon, serving as an electrical back‐contact for electronic devices. Using secondary ion mass spectrometry very low concentrations of 1014–1015 cm−3 of impurities are found originating from the soda‐lime glass with an iron content below the detection limit. Furthermore, a plateau‐like, very homogenous Al concentration of ≈4 × 1018 cm−3 over a thickness of ≈10 µm is found, which corresponds to the solubility of Al in Si at the process temperature. Complete electronic activation within the plateau region is confirmed by carrier concentration measurements using electrochemical capacitance–voltage profiling and Raman spectroscopy. Hole concentrations in the range of few 1018 cm−3 are beneficial for the p‐type base material of full‐emitter cell mc‐silicon photovoltaic devices.

Binder mediated enhanced electrochemical capacitance in sodium silicate-graphite paint coated filter paper electrodes for all-solid-state symmetric electrochemical capacitors

In this study, we have prepared a conductive paint by mixing graphite powder, fumed SiO2 particles, NaOH and water in a suitable ratio. The paint was coated on the surface of low-cost laboratory filter paper to prepare paper-based electrodes for electrochemical capacitors. Electrochemical parameters such as specific capacitance, specific energy and specific power of the electrodes were determined for 1 M H2SO4, H3PO4 and KOH electrolytes using 3-electrode electrochemical cells. All-solid-state symmetric electrochemical capacitors were constructed by using three different gel-electrolytes: PVA-H2SO4, PVA-H3PO4 and PVA-KOH. The areal capacitance values obtained for all-solid-state symmetric electrochemical capacitors with PVA-H2SO4, PVA-H3PO4 and PVA-KOH gel-electrolytes were 123.8, 94.8 and 74.7 mF cm−2 respectively. In presence of acidic electrolyte, there is significant pseudocapacitance contribution from the electrode due to presence of binder. Thus, the value of areal capacitance and hence the energy density of electrochemical capacitor with PVA-H2SO4 is highest followed by PVA-H3PO4 and lowest with PVA-KOH gel-electrolyte. It is interesting to note that in acidic electrolyte, although there is enhancement of areal capacitance, it is associated with significant reduction of cyclic stability due to the structural change of the binder. Thus, electrochemical capacitor with PVA-KOH gel-electrolyte has shown highest cyclic stability.

Carbon-Based Materials for Energy Storage Devices: Types and Characterization Techniques

The urgent need for efficient energy storage devices (supercapacitors and batteries) has attracted ample interest from scientists and researchers in developing materials with excellent electrochemical properties. Electrode material based on carbon, transition metal oxides, and conducting polymers (CPs) has been used. Among these materials, carbon has gained wide attention in Electrochemical double-layer capacitors (EDLC) due to its variable morphology of pores and structural properties as well as its remarkable electrical and mechanical properties. In this context, the present review article summarizes the history of supercapacitors and the basic function of these devices, the type of carbon electrode materials, and the different strategies to improve the performance of these devices. In addition, we present different approaches to studying the charging mechanism of these devices through different electrochemical techniques existing in the literature, since a deeper understanding of the interfacial charge storage mechanisms is also crucial in the elaboration and performance of the electrode material. We make a comparison of the different techniques and present their advantages and challenges. Taking these advances into account, we consider that the coupling between two methods/techniques provides a better understanding of the charge storage mechanisms in energy storage devices.

Conducting co-polymer derived N, S co-doped metal-free hierarchical nanoporous carbon for robust electrochemical capacitor

The present investigation reported metal-free hierarchical porous and robust Nitrogen (N), Sulphur (S) co-doped carbon (NS-CoP@C) electrode for supercapacitor application. The NS-CoP@C was synthesized by single-step carbonization and activation of thiourea co-doped aniline-pyrrole co-polymer (CoP). The thiourea acted as a doping as well as activating agent. The data of three different electrode materials PANI-PPy co-polymer (CoP), PANI-PPy co-polymer derived Carbon (CoP@C) and N, S co-doped carbon derived from PANI-PPy co-polymer (NS-CoP@C) are compared in the present report. The electrode materials were initially characterized by various spectroscopic techniques. It is observed that among the three electrode material, NS-CoP@C possess higher specific surface area (SSA), high pore volume and hierarchal porous structure with a better mesopore-to-micropore volume ratio. In a three-electrode system, NS-CoP@C possesses a high specific capacitance of 344.2 F/g @ 0.5A/g. Moreover, NS-CoP@C electrode was used to fabricate an all solid-state (PVA-1 M H2SO4 polymer gel electrolyte) and aqueous (1 M H2SO4 electrolyte) symmetrical supercapacitor devices in the two-electrode system. This NS-CoP@C electrode was used as both positive and negative electrode material in both types of devices. Among them, the solid-state device operates at a wide potential window of 2 V, as a consequence delivering an implausible energy and power density of 45.25 Wh/kg and 1025.64 W/kg while maintaining a capacity retention of 90.1 % even after 8500 charge-discharge cycles. Hence, the excellent performance of conducting PANI-PPy co-polymer-derived N, S co-doped carbon paved new ground for developing an alternative electrode for futuristic energy storage devices.

Metrics for the characteristic length scale in the random bicontinuous microstructure of nanoporous gold

Nanoporous gold (NPG) made by dealloying exemplifies materials with random bicontinuous microstructures that can be approximated by leveled-wave type models. As a distinguishing feature, the characteristic length scale – often quantified by the “ligament size” L – of NPG may be tuned over several orders of magnitude while the microstructural geometry retains a high degree of self-similarity. It is therefore essential to have at hand accurate procedures for determining the size by experiment and to match it to analogous size metrics of model scenarios. Working with a set of NPG samples of widely different size, we compare ligament size distributions determined by analysis of scanning electron micrographs to those of the leveled-wave model. The model is representative of various material types with random bicontinuous microstructures. The size distribution is remarkably uniform over the cross-section of experimental samples. Furthermore, the distribution evolves self-similarly upon coarsening, and the normalized distribution width agrees closely to that of the model. A measure for size determined by the electrochemical capacitance ratio method correlates well with L. This supports a protocol for converting between the two measures. As a dimensionless factor characteristic of the microstructural geometry of random dual phase microstructures, the product of L and the specific surface area is found consistent between experiment and model. The findings suggest conversion factors between the various metrics, and they advertise the combination of NPG and the leveled-wave model as a showcase for characterizing the characteristic length scale of random bicontinuous microstructures.

Flexible electrochemical capacitor based NiMoSSe electrode material with superior cycling and structural stability

Constructing composited electrode material is considered to be an efficient strategy to improve their electrochemical performance. It can accelerate the charge transfer speed of ions and enhance the conductivity of electrode. Meanwhile, the formation of the hybrid structure can largely avoid the aggregation of two dimensional materials and increase the electrochemical active area of the electrode. In this work, we synthesize NiMoSSe electrode materials on nickel foam by a facile hydrothermal avenue. The prepared composite shows a specific capacitance of 1035 C/g at 1 A/g due to the synergistic effect between MoS2 and MoSe2 phases. In addition, the devices are assembled with NiMoSSe samples, which offers an energy density of 82.71 Wh/kg at a power density of 2700 W/kg.

Fabrication and characterization of heavily doped n-type GaAs for mid-infrared plasmonics

N-type doping in GaAs is a self-limited process, rarely exceeding a carrier concentration level of 1019 cm−3. Here, we investigated the effect of intense pulsed light melting on defect distribution and activation efficiency in chalcogenide-implanted GaAs by means of positron annihilation spectroscopy and electrochemical capacitance–voltage techniques. In chalcogenide-doped GaAs, donor–vacancy clusters are mainly responsible for donor deactivation. Using positrons as a probe of atomic scale open volumes and DFT calculations, we have shown that after nanosecond pulsed light melting the main defects in heavily doped GaAs are gallium vacancies decorated with chalcogenide atoms substituting As, like VGa–nTeAs or VGa–nSAs. The distribution of defects and carriers in annealed GaAs follows the depth distribution of implanted elements before annealing and depends on the change in the solidification velocity during recrystallization.

Lavanta İçin Yeni Bir Teknolojik Uygulama Alanı ve Tarımsal Üreticiler İçin Ekonomik Kar Analizi

Nowadays, the energy and agriculture sectors are united for financial efficiency, and it brought the question to minds “can be stored the electrical energy that used in agriculture with an agricultural product?”. In this study, lavender essential oil, it obtained from Lavandula angustifolia, was used as a part of energy storage system. The essential oil was produced by distillation method. To energy storage performance analysis, the simple electrochemical capacitor was formed with platin foils and lavender essential oil. The capacitor application performances showed that the lavender essential oil can energy storage up to 4 Voltages (V). A capacity of 92 milli-Farad per cm2 (mF/cm2) was obtained with Lavender essential oil in the range of 0-4 V, and this value showed that lavender essential oil can be used in capacitors, as an electrolyte material. The results when evaluated in terms of agricultural economics, 1 million capacitors with a size of 1 cm2 can be produced with 1 ton lavender crops production per decare. Moreover, with lavender capacitors, the amount of energy required for a farm of 1000 hectares can be stored with 1000 capacitors of 10 cm2. Also, the stored energy is more than the farm's annual energy consumption, saving the farm ~534 USD annually on energy costs. In the case that all farm energy is produced with renewable energy sources, the annual profit is calculated as ~23697 USD. Also, the exploring of electrochemical capacitor electrolyte property of lavender essential oil could create an alternative sales pitch for agricultural producers.

High utilization efficiency of tetramethylbenzoquinone hybridized in the pores of activated carbon for high-performance electrochemical capacitor electrodes

High utilization efficiency of tetramethylbenzoquinone hybridized in the pores of activated carbon for high-performance electrochemical capacitor electrodes

Synthesis and characterization of electron beam irradiated glutinous rice husk-derived biochar and activated carbon for aqueous electrochemical capacitors

Glutinous rice husk, an abundant agricultural biowaste in Thailand, was pretreated with high energy electron beam irradiation (EBI) at doses of 500 kGy, 1000 kGy, and 1500 kGy prior to fabrication into biochar by carbonization at 500℃ under nitrogen atmosphere. The biochar was then treated with KOH and subsequently heated at 800℃, yielding activated carbon (GAC). The physical, chemical, and electrochemical properties of the as-received biochar (GB) and activated carbon (GAC) were investigated. Scanning electron microscopic images (SEM) suggested that biochar irradiated with 1500 kGy (GB-1500) has the highest porosity compared to the other samples. The electrochemical properties of GB and GAC in 3 M H2SO4 using a three-electrode system indicated that EBI affects the electrochemical performance of the material. The specific capacitance of GB-1500 (6.15 F·g-1 at 0.05 A·g-1) is higher than that of the as-received biochar, and the improved performance of the former is potentially due to the formation of structural defects upon irradiation. Finally, we observed that the specific capacitances of the GAC were much higher than those of their corresponding GB with the same irradiation doses, and the capacitances of the GAC decrease with increasing EBI dose.

Plasma-Designed Multifunctional Carbon Electrodes for High-Frequency Line Filtering Applications

Demand for higher power efficiency devices to be used in the various miniatured and portable equipment has increased and led to significant growth in the electrochemical capacitors. Currently, different available electrochemical capacitors mostly deliver the highest performance at low frequencies (less than 1 Hz) due to the microporous electrode structures and configurations. Due to these reasons, the use of such capacitors is still not commercialized because of the insufficient supply of direct current at a higher frequency range (between 100 and 200 Hz). Considering the large-scale electricity applications mainly carried with alternating current (AC), it is important to develop electronic devices that work on AC power sources. At the same time, high-power energy devices require a constant DC supply for large-scale applications. Therefore, an advanced device that can sufficiently convert AC to DC has stimulated contemporary research and designing filtering capacitors is gaining research attention. For such capacitors, it is important to design electrode architectures with high electrical conductivity, minimum contact resistance and a thickness between 1 and 10 μm, which can be achieved by depositing active material directly on the current collector. Plasma-enabled techniques have the key advantage of designing electrode architectures directly on the nanostructures and providing the desired morphology and orientation, which is favorable to maximize material–electrolyte interaction and ion transport. In this work, structure-controlled carbon nanostructures were designed using a plasma-enabled deposition approach using the advantage of the plasma catalysis effect. The nanostructures were used in the electrochemistry applications as electrodes in the filtering capacitor for the AC to DC conversion. The deposited nanostructures were vertical carbon nanoforests composed of multiple carbon nanotubes. The plasma-designed electrodes delivered a high capacitance of 430 μF in the high-frequency range (100 Hz) with a phase angle of ∼ -80°, which is excellent for filtering applications. Using such electrode architectures, a prismatic prototype was designed to test the capability of the capacitor to efficiently convert AC to DC, and the designed prototype delivered a capacitance of 12 mF at 100 Hz with long-term filtering stability (above 3 h). This excellent capacitance performance and filtering capabilities of plasma-designed carbon nanostructures open future pathways to replace conventional aluminum electrolytic capacitors for line frequency applications.

(Digital) Kilohertz-Frequency Electrochemical Capacitors Based on Vertical MoS2 Nanoflakes on Carbonized Cellulose Sheets for AC-Line Filtering

Electrochemical capacitors (ECs) with kilohertz frequency response were fabricated by the growth of vertically oriented MoS2 nanoflakes on free-standing carbonized cellulose sheets in a hydrothermal process. The cellulose was carbonized by a rapid pyrolysis process. It was shown that by tuning the MoS2 deposition time on this carbon scaffold, the frequency range and area-specific capacitance of the device can be easily adjusted. Specifically for AC-line filtering application, an EC cell with a characteristic frequency (i.e., the frequency when the phase angle reaches −45°) of 4kHz was made, which shows a specific capacitance density of 1.6mF/cm2 and a phase angle of 79.50 at 120Hz. By increasing MoS2 deposition, EC cells with an areal capacitance of 9.6mF/cm2 and a characteristic frequency of 580Hz were also fabricated.

Carbon-Based Porous Materials for Energy Storage Applications

Carbon-based materials have many applications in energy storage devices, including batteries and electrochemical capacitors. These materials are sourced from a wide range of raw materials. This project focuses on finding and evaluating electrochemical applications for porous carbon-based materials made from domestic sources. This presentation will focus on our efforts to develop and characterize these porous (at different scales) carbon materials, and on several emerging energy storage applications being investigated at Ohio University. Comparisons with other porous energy storage materials will be made in consideration of process economics and performance.

Effect of Surface Chemistry on Macrocycle and Conducting Polymer Based-Carbon Composites

Redox-active carbon composite-based electrodes, especially nitrogen-based redox active materials, can provide high power and energy storage in electrochemical capacitors. These materials include porphyrin macrocycles which are found in nature and possess unique electronic and redox-active properties from their large π-conjugated systems [1], [2]. When compositing with carbon-based materials such as carbon nanotubes (CNTs), they have shown increased stability and long-term performance. Previous work using macrocyclic tetraphenyl porphyrin sulfonate (TPPS) in CNT-based composites demonstrated improved capacitive profiles, better interfacial kinetics, and charge retention introduced in capacitive electrodes [3], [4]. On the other hand, conducting polymers with π-conjugated backbones also enabled high charge storage when used in composites [5]. To further advance these capabilities, the effects and mechanisms of surface functionalities of carbon substrates need to be investigated. For example, the presence of carboxyl groups on CNTs has been shown to improve charge storage through favourable interfacial interactions in some conducting polymers [6], [7]. The challenge as highlighted in Figure 1 lies in understanding which redox-active species, e.g. macrocycle or conducting polymer, will favour certain surface functionalities based on the nature of their interactions. Thus, a systematic investigation to design and create desirable composites and interactions for high energy and power densities, and to extend to low-cost carbon sources including waste biomass-based activated carbons.In this work, we conducted a systematic study comparing the effect of several surface functionalities like carboxyl groups on TPPS macrocycles and on conducting polymer-based carbon composites to answer the question on why certain surface functionalities are favored for each species. Preliminary studies have shown presence of TPPS has increased the capacitive profiles, reaction kinetics and rate capabilities of CNT composites, exceeding the conducting polymer counterparts. But this capacitive increase can be further improved through surface modification. This study leveraged layer-by-layer deposition approaches to fabricate redox-active carbon composites, followed by electrochemical characterizations using cyclic voltammetry and electrochemical impedance spectroscopy. Surface morphology was studied using electron microscopy while surface functional groups were investigated using x-ray photoelectron spectroscopy. The findings from this study can be used to implement systematic surface modification for redox-active carbon composites to improve energy storage, towards a more sustainable future.

(Digital Presentation) Self-Discharge Study of Carbon-Based Supercapacitors with Tunable Pore Size

Electrochemical double-layer capacitors (EDLCs), as a major type of energy storage devices besides rechargeable batteries such as lithium-ion batteries, holds excellent properties such as high power density and ultra-long cycling stability[1-3]; however, its fast self-discharge process has become the major issue that impedes its development and application. Even though research on EDLCs’ self-discharge has demonstrated that the fast self-discharge rate can be tuned even repressed through modifying certain structural properties of electrodes or electrolytes[4-9], to the end of realizing full control over the self-discharge process requires unveiling the fundamental relation between structural parameters (i.e., the pore structure, the surface functionalities, the electrolytic ion size and shape, and etc.) and the self-discharge performance.Carbon, due to its superior chemical stability, high surface area, natural abundance, etc.[4,10], has become one of the main types of electrode materials under extensive research interest for developing advanced EDLCs. Herein, we focus on tuning the pore size, one of the major structural properties of carbon materials relating to its electrochemical performance, to study its effects on self-discharge process and to learn how to construct the optimal pore structure with respect to certain application requirements.In this work, porous carbon materials with designed pore structure are prepared via soft-template method to analyse the self-discharge performance. Through investigating the effects of pore size, as the single variable, on the self-discharge process, as well as on the micro-electrochemical process on the electrode/electrolyte interface, underlying mechanism between pore size and the self-discharge performance has been constructed. These findings should provide guidance on how to locate the optimal pore size for a chosen electrolyte and to realize control over self-discharge, which will serve as solid references for designing the next-generation EDLCs with high performance and controllable self-discharge rates. Reference [1] X. Chen, R. Paul, L. Dai, Natl. Sci. Rev., 2017, 4(3), 453-489.[2] G. Wang, L. Zhang, J. Zhang, Chem. Soc. Rev ., 2012, 41, 797-828.[3] Y. Liu, Y. Shen, L. Sun, J. Li, C. Liu, W. Ren, F. Li, L. Gao, J. Chen, F. Liu, Y. Sun, N. Tang, H. Cheng, Y. Du, Nat. Commun., 2016, 7, 10921.[4] Q. Zhang, C. Cai, J.W. Qin, B.Q. Wei, Nano Energy., 2014, 4, 14-22.[5] T. Tevi, H. Yaghoubi, J. Wang, A. Takshi, J. Power Sources., 2013, 241, 589-596.[6] L. Chen, H. Bai, Z. Huang, L. Li, Energy Environ. Sci., 2014, 7, 1750-1759.[7] G. Shul, D. Bélanger, Phys. Chem. Chem. Phys., 2016, 18, 19137-19145.[8] M. Xia, J. Nie, Z. Zhang, X. Lu, Z.L. Wang, Nano Energy., 2018, 47, 43-50.[9] J. Menzel, E. Frackowiak, K. Fic, Electrochimica Acta, 2020, 332, 135435.[10] D.P. Dubal, O. Ayyad, V. Ruiz, P. Gomez-Romero, Chem. Soc. Rev., 2015, 44, 1777–1790. Figure 1

ZnxNi1-xSe2 nanoparticles grown on functionalized nickel foam as binder-free electrocatalysts for HER in acidic and alkaline media

Metal ion doping is considered as an effective approach towards increasing the activity of transition metal selenide-based catalysts for electrocatalytic hydrogen evolution reaction (HER). Herein, we report a one-pot synthesis of Zn doped NiSe2 nanoparticles (ZnxNi1-xSe2, where x = 0.25, 0.50, 0.75) grown on nickel foam (NF) and the efficacy of ZnxNi1-xSe2/NF has been investigated towards electrocatalytic HER. The synthesized materials were systematically characterized and their electrocatalytic HER activity was tested in acidic and alkaline media, among which Zn0.25Ni0.75Se2/NF has demonstrated a relatively higher electrocatalytic performance. Zn0.25Ni0.75Se2/NF required very low overpotentials of 126 mV and 158 mV for HER to attain 10 mA cm−2 current density in 0.5 M H2SO4 and 1 M KOH, respectively. The inherent electrochemical properties such as electrochemical active surface area and double layer capacitance have been measured and Zn0.25Ni0.75Se2/NF has shown superior activity. Also, the binder-free Zn0.25Ni0.75Se2/NF electrocatalyst has illustrated excellent stability during continuous evolution of hydrogen for 12 h in acidic and alkaline medium.

Microstructural Engineering of Flow Battery Electrodes with Non-Solvent Induced Phase Separation

Rising levels of greenhouse gases urge the decarbonization of human activities. Electrification of strategic sectors such as transport, industry, and heating necessitates affordable, safe, and dispatchable large-scale energy storage systems. Redox flow batteries (RFBs) stand as a promising long-duration and large-scale energy storage technology due to their design features[1]. Ongoing research focuses on engineering key cell components (e.g. membranes, electrodes, active materials) to improve cost competitiveness. This work focuses on the fabrication of novel porous carbon electrodes which strongly influence the performance and cost of the technology. The requirements for porous electrodes liquid-phase electrochemical reactors are contradictory: a large surface area is needed to overall exchange current density, but also minimal pressure losses to decrease pumping costs. Additionally, surface properties of the electrode dictate the reaction kinetics whereas its microstructure controls the mass transport of the reactants within the reactor area[2]. However, the current state-of-the-art porous electrodes for RFBs consists of carbon-fiber materials repurposed from other electrochemical technologies (e.g. polymer electrolyte fuel cells) which do not offer a favorable tradeoff between transport properties and surface area. Additionally, their production involves complex manufacturing processes resulting in high cost and limited morphological versatility. Therefore, there is a need to develop alternative synthetic platforms which offer tailorable microstructures and surface properties to match the requirements of emerging electrochemical applications, such as redox flow batteries. In this work, we draw inspiration from the membrane technology and employ non-solvent induced phase separation (NIPS) as a method to synthesize porous carbon electrodes for RFBs[3,4].Here, we present our latest efforts to develop a manufacturing route enabling the control of microstructural features of carbonaceous porous electrodes for RFBs. The microstructure of the carbon scaffold is determined by the nature and composition of the polymer blend used to cast the electrode precursor. We use polyacrylonitrile as scaffold precursor and polyvinylpyrrolidone as a pore forming agent, dissolved in an organic solvent (i.e., dimethylformamide, dimethylsulfoxide or N-methylpyrrolidone). The polymer blends were cast into a mold and immersed in a water coagulation bath prior to being stabilized (270 °C) and carbonized (1050 °C). Various process parameters (e.g. polymer concentration, bath temperature, solvent type) governing the final electrode properties were leveraged to control structural features, opening new opportunities for the fabrication of diverse microstructures (i.e., porosity gradient, isoporosity and with macrovoids). Electrochemical double layer capacitance and pressure drop measurements show an increased design space compared to carbon-fiber electrodes, confirming the versatility of the synthetic route. Microstructural analysis of the prepared NIPS electrodes reveals two porosity domains: large finger-like macrovoids (throat diameter >50 μm) and smaller interconnected microvoids (pore diameter 2-15 μm). Flow cell polarization and electrochemical impedance spectroscopy measurements in two common flow battery electrolytes, an Fe2+/Fe3+ single electrolyte and vanadium full cell, show improvements in performance compared to traditional electrodes. An increase in the polymer concentration of the polymer blend solution produced NIPS electrodes with smaller pores and resulted in better mass transport within the electrode. When the temperature of the coagulation bath was increased to 40 ºC, the electrode has higher electrochemically active surface area, producing a significant power increase in the sluggish vanadium electrolyte. Overall, the NIPS electrodes operate at significantly lower activation and mass transport overpotentials in all-vanadium RFBs, generating higher electrical power at the expense of a slight pressure drop increase. Although preliminary, we demonstrate the potential of NIPS to manufacture electrodes with tailorable microstructures for convection-enhanced electrochemical technologies.[1] T. M. Gür, Energy Environ. Sci. 2018, 11, 2696.[2] A. Forner-Cuenca, E. E. Penn, A. M. Oliveira, F. R. Brushett, J. Electrochem. Soc. 2019, 166, A2230.[3] R. R. Jacquemond, C. T.-C. Wan, Y.-M. Chiang, Z. Borneman, F. R. Brushett, K. Nijmeijer, A. Forner-Cuenca, Cell Reports Physical Science 2022, 3, 100943.[4] C. T.-C. Wan, R. R. Jacquemond, Y.-M. Chiang, K. Nijmeijer, F. R. Brushett, A. Forner-Cuenca, Adv. Mater. 2021, 10. Figure 1

A review on effect of conducting polymers on carbon-based electrode materials for electrochemical supercapacitors

Supercapacitors, commonly referred to as electrochemical capacitors, are a significant type of energy storage devices with more energy density than capacitors, greater power density, and longer cycle life than batteries. Conventionally, the electrode material of supercapacitors is composed of metal oxides, inorganic complexes, carbon-based materials, and conducting polymers. Researchers have attempted numerous combinations of aforementioned materials to create electrode material with enhanced electrochemical properties. However, supercapacitor (SC) electrodes constructed with pure conducting polymers (CPs) have poor cycling stability, resulting in a rapid decrease in specific capacitance. To improve the electrochemical property of such materials, researchers have attempted to construct binary and ternary composites of various CPs by mixing them with carbonaceous materials and metal oxides. In this review, SC electrode materials prepared from CPs, such as polyaniline (PANI), polythiophene (PTh), polypyrrole (PPy) and their composites with carbonaceous materials such as activated carbon (AC), carbon nanotubes (CNTs), reduced graphene oxide (rGO), graphene and carbon quantum dots have been discussed.

G-C3N4/WO3(H2O)0.33 nanostructured electrode for hybrid asymmetric-supercapacitor

The demand for high-energy storage supercapacitors with appropriate designs has been emerging in recent times. Aimed at enhancing the electrochemical storage performance of supercapacitors, g-C3N4/WO3(H2O)0.33 (GCN/WO) nanostructures have been prepared in a simple wet impregnation process by mixing the synthesized g-C3N4, and WO3(H2O)0.33 materials and their performances were compared systematically with their individual components. The successful formation of C3N4/WO3(H2O)0.33 nanostructure has been confirmed by the XRD, SEM, EDS, HR-TEM, HAADF and XPS spectroscopy analyses. The prepared GCN/WO nanostructures showed greater specific capacitance of 466.88C g−1 at 1.5 A g−1 than their counterparts (GCN 87.87C g−1 and WO 140.64C g−1) with remarkable cyclic stability of 98.6% over 10000 cycles. Notably, the fabricated hybrid asymmetric supercapacitor devices (HASDs) exhibited ultrahigh power density of 255.23 W kg−1 at energy density of 10.07 Wh kg−1. The enhanced electrochemical capacitor characteristics of GCN/WO nanostructures could be attributed to the positive synergistic effect of GCN and WO. Thus, the strategy utilizing this synergistic effect between GCN and WO in a simple impregnation process is a viable alternative to fabricate the high capacitance electrodes for application in supercapacitors.

Electrochemical capacitance spectroscopy based determination of antibodies against SARS-CoV-2 virus spike protein

In this study, we are reporting a novel electrochemical capacitance spectroscopy (ECS) platform designed for the sensitive and label-free detection of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus spike protein (anti-rS) in diluted blood serum. The determination of anti-rS is crucial for identification individuals who have been infected by SARS-CoV-2 virus and may have acquired immunity. The rS protein was immobilized on a screen-printed carbon electrode, which was incubated in diluted blood serum containing anti-rS antibodies. Label-free ECS was applied for the determination of interaction between immobilized rS and free-standing anti-rS. Here reported bioanalytical platform demonstrated high sensitivity and specificity in detecting anti-rS, achieving a limit of detection of 4.38 nM. This versatile platform could be further enhanced by applying various electrode materials and adapting this platform to detect antibodies against some other proteins. Our findings have significant implications for the development of affordable, scalable biosensing platforms capable to provide rapid and accurate public health screening and monitoring, particularly in the context of the coronavirus disease 2019 (COVID-19) pandemic.