Electrical Capacitance Research Articles

Ultrathin Zincophilic Interphase Regulated Electric Double Layer Enabling Highly Stable Aqueous Zinc-Ion Batteries

HighlightsElectric double-layer regulation enabled by an ultrathin multifunctional solid electrolyte interphase layer with zincophilicity and rapid transport kinetics.Lowered potential drop over the Helmholtz layer and suppressed diffuse layer.Inhibited side reactions and uniform zinc deposition.

Flight-ready Electrical Capacitance Tomography SMARTTS tank for use with cryogenics

The Atout SMARTTS (SMART Tanks for Space) system allows the propellant mass distribution in a storage vessel to be measured accurately under several motion and gravity conditions and at any fill level. Based on Electrical Capacitance Tomography (ECT), SMARTTS systems incorporate electrodes on the inside of the tank, electrical connections to these electrodes, and capacitance measurements. Interpretation of the capacitance measurements is done through the Atout software, providing live images, fill levels and center of mass measurement of the propellant within the tank. The main objective of this work is to demonstrate the successful operation of a flight-ready aluminum tank with integrated SMARTTS electrodes and feedthroughs at cryogenic temperatures. The experiments presented herein consist of three submersion cycles in which the tank is lowered into an open-top dewar filled with liquid nitrogen. During the cycle, the tank is filled with liquid nitrogen when lowered into the dewar, then drained as it is lifted out. Successful operation of the SMARTTS system has been proven via live images of the fluid in the tank, as well as measured fill volume and center of mass of fluid. The materials and sensors have performed satisfactorily with no failures or post-experiment signs of damage.

Synaptic Plasticity Modulation of Neuromorphic Transistors through Phosphorus Concentration in Phosphosilicate Glass Electrolyte Gate.

This study proposes a phosphosilicate glass (PSG)-based electrolyte gate synaptic transistor with varying phosphorus (P) concentrations. A metal oxide semiconductor capacitor structure device was employed to measure the frequency-dependent (C-f) capacitance curve, demonstrating that the PSG electric double-layer capacitance increased at 103 Hz with rising P concentration. Fourier transform infrared spectroscopy spectra analysis facilitated a theoretical understanding of the C-f curve results, examining peak differences in the P-OH structure based on P concentration. Using the proposed synaptic transistors with different P concentrations, changes in the hysteresis window were investigated by measuring the double-sweep transfer curves. Subsequently, alterations in proton movement within the PSG and charge characteristics at the channel/PSG electrolyte interface were observed through excitatory post-synaptic currents, paired-pulse facilitation, signal-filtering functions, resting current levels, and potentiation and depression characteristics. Finally, we demonstrated the proposed neuromorphic system's feasibility based on P concentration using the Modified National Institute of Standards and Technology learning simulations. The study findings suggest that, by adjusting the PSG film's P concentration for the same electrical stimulus, it is possible to selectively mimic the synaptic signal strength of human synapses. Therefore, this approach can positively contribute to the implementation of various neuromorphic systems.

Using electrical impedance spectroscopy to identify equivalent circuit models of lubricated contacts with complex geometry: In-situ application to mini traction machine

Electrical contact resistance or capacitance as measured between a lubricated contact has been used in tribometers, partially reflecting the lubrication condition. In contrast, the electrical impedance provides rich information of magnitude and phase, which can be interpreted using equivalent circuit models, enabling more comprehensive measurements, including the variation of lubricant film thickness and the asperity (metal-to-metal) contact area. An accurate circuit model of the lubricated contact is critical as needed for the electrical impedance analysis. However, existing circuit models are hand derived and suited to interfaces with simple geometry, such as parallel plates, concentric and eccentric cylinders. Circuit model identification of lubricated contacts with complex geometry is challenging. This work takes the ball-on-disc lubricated contact in a Mini Traction Machine (MTM) as an example, where screws on the ball, grooves on the disc, and contact close to the disc edge make the overall interface geometry complicated. The electrical impedance spectroscopy (EIS) is used to capture its frequency response, with a group of load, speed, and temperature varied and tested separately. The results enable an identification of equivalent circuit models by fitting parallel resistor-capacitor models, the dependence on the oil film thickness is further calibrated using a high-accuracy optical interferometry, which is operated under the same lubrication condition as in the MTM. Overall, the proposed method is applicable to general lubricated interfaces for the identification of equivalent circuit models, which in turn facilitates in-situ tribo-contacts with electric impedance measurement of oil film thickness – it does not need transparent materials as optical techniques do, or structural modifications for piezoelectric sensor mounting as ultrasound techniques do.

Heat treatment of iron/carbon composites for energy storage: effect on physicochemical and electrochemical properties

Carbon materials are widely used as supercapacitor electrodes while iron oxides and other iron compounds are promising electrode materials due to its pseudocapacitive contribution. This work deals with the preparation and electrochemical characterization of iron/carbon composites for supercapacitor electrode applications. The carbon precursor samples were prepared from a carbonization of babassu coconut endocarp, and the iron/carbon nanocomposites were obtained by precipitation synthesis using iron salt, followed by a heat treatment at different temperatures. The electrochemical characterization of the samples show that, at low current density, the sample without iron compounds shows the higher electrical capacitance, up to 98 F g-1 in 2 M H2SO4. This good performance can be associated to a pseudocapacitive contribution of the oxygenated functional groups present in this sample. However, at higher current densities, the best electrochemical behaviour was achieved for the sample treated at 1000 °C. This good performance is may be associated to the Feº and Fe3C nanoparticles present in the sample which can enhance its electrical conductivity. On the other hand, is no there clearly evidence of pseudocapacitive contribution of the iron particles. Future works will seek to improve the surface area of the materials with the aim to increase the double layer capacitance, and also to perform electrochemical studies using other electrolytes.

Synthesis and Electrochemical Properties of Fe3O4/C Nanocomposites for Symmetric Supercapacitors

In the work, nanostructured Fe3O4/C composites based on natural raw materials (beet pulp and corn stalks) are synthesised in various ways. Iron chloride FeCl3 is used as an activator. The synthesised composites are investigated using the following methods, scanning electron microscopy, X-ray diffractometry, nitrogen adsorption/desorption porometry, magnetometry, impedance and galvanostatic measurements. The presence of nanosized Fe3O4 magnetite in the synthesised carbon structures is disclosed. Based on the magnetic measurements, the particle size of Fe3O4 is on average 50 nm for the sample of the composite synthesised from beet pulp in one step, 30 nm for the sample of the composite synthesised from beet pulp in two steps, 33 nm for the composite synthesised from corn stalks in one step, and 29 nm for the composite synthesised from corn stalks in two steps. It is shown that the two-step synthesis using pre-carbonised raw materials gives the specific capacitance of the composite made with beet pulp at 96 F/g, and for the composite made with corn stalks at 95 F/g. The high coulombic efficiency (>95%) and the stability of the electrical capacitance during long-term cycling make it possible to use Fe3O4/C composites for the manufacture of supercapacitor electrodes with aqueous electrolytes.

A Novel Computational Imaging Algorithm for Electrical Capacitance Tomography

High-precision images enable electrical capacitance tomography (ECT) to obtain more reliable measurement results, meaning that the reconstruction algorithm is particularly important. Some excellent numerical algorithms have successfully solved the inverse problem for ECT imaging, but their imaging quality is relatively low. To solve this problem, this paper proposes a new reconstruction algorithm based on regularized extreme learning machines (RELMs). The implementation of the algorithm is mainly divided into two steps: (1) according to a large number of training samples, the RELM model can be obtained by the iterative split Bregman (ISB) algorithm, which can describe the mapping relationship between the capacitance correlation coefficient and the imaging target well, and (2) the capacitance correlation coefficient is calculated, which is then used as input to the RELM model to predict the final imaging. Both simulation and experimental results show that the RELM algorithm achieves greater improvement in imaging quality and robustness, and provides new development ideas for the ECT.

Incorporation of edge-N into La-doped hierarchical carbon framework enables high-efficiency phosphate electrosorption: Boosting accessible active centers and bridging charge transfer paths

Achieving high-efficiency removal of phosphate has been an urgent issue to combat eutrophication and meet ever-stricter emission standards. Electro-assisted adsorption, a mild electrochemical technology, demonstrated great potential for wastewater treatment owing to the merits of considerable removal performance, facile operation, and energy efficiency. Exploring and boosting the properties of electrode materials is exceedingly vital for technological advancement. In this study, the novel edge-N decorated La-doped hierarchical carbon composites (LNPCs) were developed via in-situ nucleation and one-pot pyrolysis strategy as phosphate capture electrodes. The LNPC900 electrode exhibited an ultrahigh phosphate removal capability of 533.06 mg PO43- g−1 at 1.2 V, surpassing most of the reported electrode materials. Furthermore, this electrochemical system also performed well in the purification of natural river water with low phosphate concentration, where the treated concentration was below the first-class emission standard in China (0.5 mg P L−1). Comprehensive analysis and theoretical calculations indicate that the synergistic property of edge-N and small graphitic carbon nanodomains ensured more accessible active centers and conductive efficiency. The superb phosphate removal capability mainly originated from the coupling contribution of the electrical double layer capacitance, ligand exchange, and electrostatic attraction. This study possesses insight into the theoretical basis for the practical application of phosphate electrosorption and provides a new level of the technology.

Pengaruh Suhu Terhadap Sifat Listrik Polimer Konduktif Polianilin TiO2 Berpenguat Nano Serat Pinang

This research serves to see the effect of temperature on conductive polymers, and the temperature variations used are 27 ℃, 37 ℃, 47 ℃, 55 ℃, 67 ℃, and 77 ℃. The polyaniline used is pure polyaniline and a mixture of polyaniline, TiO2, and nano areca fiber with a mixture percentage of 70%: 27%: 3%. Polyaniline is produced from polymerization of aniline monomer and ammonium peroxydisulfate and nano arecafibers are used from nano arecafibers that have been produced in previous research. Electrical properties testing consisted of electrical conductivity and capacitance tests using an LCR meter. The results showed the lowest conductivity value at 27 ℃ was 0.18 × 10-2 S /cm, and the highest conductivity value at 77 ℃ was 1.22 × 10-2 S/cm for pure polyaniline, while the mixed polyaniline obtained the lowest conductivity value at 27 ℃ was 0,85 × 10-2 S/cm, and the highest value at 77 ℃ was 3.61 × 10-2 S/cm. For the capacitance test, the highest value was obtained at 6.8 μF and 18.9 μF. From the results obtained, the higher the temperature, the higher the conductivity value produced, while the capacitance results show that the higher the temperature used, the lower the capacitance value.

Higher hydrogen fractions in dielectric polymers boost self-healing in electrical capacitors.

Electrical capacitors are omnipresent in modern electronic devices, in which they swiftly release large portions of energy on demand. The capacitors may suffer from arc discharges due to local structural heterogeneities in their components and inappropriate exploitation practices. High energies of the arc discharge are transferred as phonons to the electrode and dielectric film, which burn out locally. The dielectric breakdown takes place. The complete burnout leads to the isolation of the failed region and the capacitor's self-healing. The emerging soot can form a semiconducting channel and damage the capacitor. The efficiency of self-healing depends on the dielectric properties of the soot and its amount. We employ reactive molecular dynamics simulations to reveal the regularities of the high-temperature polymer destruction and record by-products emerging during this process. We found the formation of multiple volatile low-molecular compounds and contaminated quantum carbon dots (CQD) designated as soot. The percentage of carbon in soot is higher compared to the polymer. Furthermore, the CQD contains numerous unsaturated C-C bonds and aromatic C6-rings suggesting an enhanced electrical conductivity. The size of the CQD depends on the available volume, i.e., on the spatial scale of the dielectric breakdown. The elemental composition of the soot is unique for each polymer. Polypropylene undergoes the most efficient self-healing thanks to containing a large molar fraction of hydrogen atoms. The results are addressed to the experts in electrical engineering and polymer fine-tuning.

Well-modulated interfacial ion transport enables D-sorbitol/PEDOT:PSS fibers to sense brain electrophysiological signals in vivo.

A neuroelectrode can be easily prepared using a wet-spun fiber of D-sorbitol/PEDOT:PSS. At a D-sorbitol/PEDOT:PSS weight ratio of 6, the fiber is well-modulated with suitable characters, including the morphology, crystallization, diffusion resistance (179 kΩ), and electric double-layer capacitance (2.72 μF), for sensitive recording of brain activity during somatosensory stimulation and seizures. Additionally, the fiber is highly biocompatible with the brain. This study presents a simple and controllable strategy for the chemical construction of conducting polymer-based neurosensors.

Impact of gate electrode on free chlorine sensing performance in solution-gated graphene field-effect transistors.

Free chlorine is widely used to disinfect water used for drinking and food processing. This requires highly sensitive, simple, and capable continuous-measurement sensors to enable the concentration of free chlorine in water to be monitored and controlled. Free chlorine sensors based on solution-gated graphene field-effect transistors (GFETs) are a suitable platform for highly sensitive and continuous measurements. However, their sensing mechanisms require further elucidation to improve their performance. In this study, we focused on the gate electrode and investigated its influence on the sensing performance. Using the free chlorine sensor based on the solution-gate GFET, we showed that the Dirac point voltage in the transfer curve changed significantly as the free chlorine concentration changed, and the electric double-layer capacitance of the gate electrode decreased. Furthermore, we demonstrated that a solution-gated GFET using graphene or boron-doped diamond as the gate electrode could be used to detect changes in the free chlorine concentration in the concentration range of tap water. The sensing performance in the low concentration range benefits from the wide potential window of carbon-based electrodes, which do not have electrochemically active sites. Using these carbon-based materials as gate electrodes, GFETs have the potential to be used as durable sensors that are resistant to surface fouling and oxidation.

Ultrahigh energy storage in multilayer BiFeO3–BaTiO3–NaTaO3 relaxor ferroelectric ceramics

The rising challenge of high-density electric energy storage has accelerated the research of electric energy-storage capacitors due to their high power density and voltage resistance, excellent temperature stability, and environmental friendliness.

Electrical Capacitance Tomography of Cell Cultures on a CMOS Microelectrode Array.

Electrical capacitance tomography (ECT) can be used to predict information about the interior volume of an object based on measured capacitance at its boundaries. Here, we present a microscale capacitance tomography system with a spatial resolution of 10 microns using an active CMOS microelectrode array. We introduce a deep learning model for reconstructing 3-D volumes of cell cultures using the boundary capacitance measurements acquired from the sensor array, which is trained using a multi-objective loss function that combines a pixel-wise loss function, a distribution-based loss function, and a region-based loss function to improve model's reconstruction accuracy. The multi-objective loss function enhances the model's reconstruction accuracy by 3.2% compared to training only with a pixel-wise loss function. Compared to baseline computational methods, our model achieves an average of 4.6% improvement on the datasets evaluated. We demonstrate our approach on experimental datasets of bacterial biofilms, showcasing the system's ability to resolve microscopic spatial features of cell cultures in three dimensions. Microscale capacitance tomography can be a low-cost, low-power, label-free tool for 3-D imaging of biological samples.

Digital twin-assisted three-dimensional electrical capacitance tomography for multiphase flow imaging

Digital twin-assisted three-dimensional electrical capacitance tomography for multiphase flow imaging

High-Speed Flow Imaging With Adaptive Electrical Capacitance Tomography for Improved Accuracy

High-Speed Flow Imaging With Adaptive Electrical Capacitance Tomography for Improved Accuracy

Supplementary comparisons of reference measuring systems of electric capacitance and loss dissipation factor on AC high voltage of power frequency COOMET 604/RU-a/13 (COOMET.EM-S18)

Main textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Fractional Optimization With the Learnable Prior for Electrical Capacitance Tomography

Fractional Optimization With the Learnable Prior for Electrical Capacitance Tomography

АНАЛИЗ ЭКСПЛУАТАЦИОННЫХ ХАРАКТЕРИСТИК ПРИБОРОВ УЧЕТА МОЛОКА

The foreign and domestic individual milk yield accounting devices analysis is carried out. The dairy industry development’s main directions for production rate’s and milk quality increasing are given. The development of these areas is impossible without for milk collecting, accounting and primary processing. Milk accounting on modern domestic and foreign farms can be both group and individual. At group accounting, milk from cows enters into a cooling tanker, and then, through a metering device, into the tanks of vehicles for transportation for enterprises and plants processing. This is a simple and convenient method using only one milk meter, however, by this accounting method, the milking process control impossible. The individual milk yield counters’ using is important for particular cow milk yield predicting for cow health preserving due to milking cups’ absence overexposing. Also, individual milk accounting allows to separate mastitis infected milk from the healthy cows’ milk, that allows to reject only part of farmer milk producing, and not the entire batch, as it would be in the case with group accounting. A brief description of the types of sensors for individual and group milk metering from foreign and domestic producers is presented. An advantages and disadvantages of the considered milk metering devices comparative assessment is given. It is concluded that there is a necessity developing for a system that will meet the following requirements: the ability with a milk-and-air mixture working; device’s high autonomy; construction’s simplicity; high accuracy. Based on the analysis of milk meter designs, it can be argued that the most design promising should be based on the capacitive principle, when the milk-and-air mixture flow will change the electrical capacitance

Estimating the long-term drift of travelling measurement standards for comparisons

In metrology, it is essential to analyse the instrumental drift of measuring instruments and measurement standards. Each reference instrument is periodically calibrated according to a frequency determined by the laboratory. Calibration establishes the metrological state of the instrument on a certain date of calibration. However, it is necessary to know the state of the measuring instrument during or after the calibration.
 Reliable accounting for drift plays an important role in maintaining measurement accuracy. Otherwise, it can lead to significant measurement errors. Accounting for time drift is mandatory when conducting international comparisons of national measurement standards. The drift uncertainty can be evaluated from its history of successive calibrations. In the absence of such a history, the magnitude order of the calibration uncertainty can be estimated.
 The analysis of the long-term drift of travelling measurement standards is limited to examples of key and supplementary comparisons of measurement standards of electrical capacitance. Quite a lot of such comparisons were conducted both by the Consultative Committee for Electricity and Magnetism (CCEM) and by most of the Regional Metrology Organizations (RMOs). There are international standards and guides that describe various statistical methods of analysing the measurement results.
 For capacitance measurement standards, time drift is predictable and nearly linear. For comparisons of measurement standards, a linear model is more than often applied, as a travelling measurement standard with excellent stability characteristics is used. The consistent results have been obtained. The linear model was applied to estimate the drift of travelling measurement standards during the key and supplementary comparisons (COOMET.EM-K4, COOMET.EM-S4, and COOMET.EM-S13) of measurement standards of electrical capacitance. The estimation of the long-term drift of measurement standards of electrical capacitance as travelling measurement standards for comparisons using a polynomial regression are presented.