Electrical Properties Of Electrodes Research Articles

Fabrication and Characterization of a Marine Wet Solar Cell with Titanium Dioxide and Copper Oxides Electrodes

One of the effective ways of utilizing marine environments is to generate energy, power, and hydrogen via the effect of photocatalysts in the seawater. Since the ocean is vast, we are able to use its large area, but the power generation system must be of low cost and have high durability against both force and corrosion. In order to meet those requirements, this study focuses on the fabrication of a novel marine wet solar cell composed of a titanium dioxide photoanode and a copper oxide photocathode. These electrodes were deposited on type 329J4L stainless steel, which possesses relative durability in marine environments. This study focuses on the characterization of the photocatalytic properties of electrodes in seawater. Low-cost manufacturing processes of screen-printing and vacuum vapor deposition were applied to produce the titanium dioxide and copper oxides electrodes, respectively. We investigated the photopotential of the electrodes, along with the electrochemical properties and cell voltage properties of the cell. X-ray diffraction spectroscopy (XRD) of the copper oxides electrode was analyzed in association with the loss of photocatalytic effect in the copper oxides electrode. Although the conversion efficiency of the wet cell was less than 1%, it showed promising potential for use in marine environments with low-cost production. Electrochemical impedance spectroscopy (EIS) of the cell was also conducted, from which impedance values regarding the electrical properties of electrodes and their interfaces of charge-transfer processes were obtained. This study focuses on the early phase of the marine wet solar cell, which should be further studied for long-term stability and in actual marine environmental applications.

Micro-Flexible-Surface Probe for Determining Spatially Heterogeneous Electronic Conductivity of Lithium-Ion Battery Electrode Films

Lithium-ion battery electrodes are generally made up of porous, thin films that are structurally heterogeneous on multiple length scales due to the manufacturing process. This in turn causes spatial variability in the electrical properties of the film. This work reports development of a low-cost, flexible probe for measurement of film conductivity and contact resistance to the current collector. When mounted on a moveable stage, the probe can quickly produce maps of electrode electrical properties at sub-millimeter resolution. Bulk conductivity and contact resistance are determined by inverting a 2D model of the experiment. The method is validated using a conductive silicone rubber placed on top of plain and corroded steel with significant contact resistance variation. Measurements on commercial quality electrode films, two cathodes and one anode, show statistically significant macro-variations in film properties perpendicular to the rolling direction and micro-variations throughout the film, variations that will impact electrode performance. The flexible-surface probe can be a significant tool to determine and minimize sources of variation in electrode manufacturing.

Electron Density-Change in Semiconductor by Ion-Adsorption at Solid-Liquid Interface.

The change in electrical properties of electrodes by adsorption or desorption at interfaces is a well-known phenomenon required for signal production in electrically transduced sensing technologies. Furthermore, in terms of electrolyte-insulator-semiconductor (EIS) structure, several studies of energy conversion techniques focused on ion-adsorption at the solid-liquid interface have suggested that the electric signal is generated by ionovoltaic phenomena. However, finding substantial clues for the ion-adsorption phenomena in the EIS structure is still a difficult task because direct evidence for carrier accumulation in semiconductors by Coulomb interactions is insufficient. Here, a sophisticated Hall measurement system is demonstrated to quantitatively analyze accumulated electron density-change inside the semiconductor depending on the ion-adsorption at the solid-liquid interface. Also, an enhanced EIS-structured device is designed in an aqueous-soaked system that works with the ionovoltaic principle to monitor the ion-dynamics in liquid electrolyte media, interestingly confirming ion-concentration dependence and ion-specificity by generated peak voltages. This newly introduced peculiar method contributes to an in-depth understanding of the ionovoltaic phenomena in terms of carrier actions in the semiconductors and ionic behaviors in the aqueous-bulk phases, providing informative analysis about interfacial adsorptions that can expand the scope of ion-sensing platforms.

Scratching the electrode surface: Insights into a high-voltage pulsed-field application from in vitro & in silico studies in indifferent fluid

Electroporation is employed ever more frequently and broadly to deliver energy to tissues and liquid media in various applications, thus answering questions on the associated electrochemistry and electrode material alteration is becoming important. The aim of the present study is firstly to introduce and elucidate the basic relations between voltage, current, electrical impedance, and heat generation in the medium, and secondly, to characterize electrode material alteration due to pulse delivery, both by performing an in vitro and an in-silico study. Saline was used as a(n) (over)simplified model medium representing biological tissue, and exposed to high-amplitude, high-current electroporation pulses of varying duration, polarity, and pulse repetition rate. The controlled experiment was conducted by using seven different electrode metals of high purity, delivering pulses using three different protocols, and concurrently or sequentially measuring as many physical properties as available (electric current, voltage, electrode-electrolyte impedance, temperature). The intent is to present a multi-physics approach to what is occurring during procedures such as in vivo electrochemotherapy, gene delivery and in vitro gene transfection, intracardiac irreversible electroporation/pulsed-field ablation, or indeed electroporation in liquid food products such as juice. Modelling is also used to see whether it is possible to detect, via electrical measurements, any alterations in medium properties (e.g. composition) due to electrochemical effects, and if any such effects can be decoupled from the ohmic and thermal effects. Water electrolysis was observed indirectly (gas production), but not detected by electrical measurements during pulse application. Reactions at the electrodes alter the electrode electrical properties depending on the electrode material as expected, which might be important especially in applications where the same electrodes are used for delivery of electroporation pulses and also for sensing small electrical signals such as ECG for example. The demonstrated approach using saline as a model medium allows for rapid validation, and can more easily be developed further, as compared to experiments with more complex electrode materials (e.g. alloys), media (e.g. fluids, growth media, biological cell suspensions), or tissues.

Effects of impact conditions on the electrical and mechanical properties of supersonic cold sprayed Cu–Ni electrodes

Supersonic cold sprayed Cu and Ni particles were deposited on Si wafers for potential use as solar-cell front electrodes. Line-printed Ni–Cu electrodes were successfully fabricated with thicknesses between 30 and 50 μm. Choice of carrier gas (nitrogen and air) and effects of particle size and impact velocity on the electrical and mechanical properties of these Ni–Cu electrodes were quantified. The carrier gas had no discernable effect on electrode properties while increased particle sizes slightly decreased electrode specific resistivities. Impact velocity had the most pronounced influence on electrode electrical properties. Both the contact and specific resistivities decreased nearly linearly with increasing impact velocity. Adhesion strength was measured with a STAB-TEST instrument and found sufficient for all measured electrodes. The electrodes were further characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and auger electron spectroscopy.

Synthesis and Dielectric Characterization of Multi-walled Carbon Nanotubes/Polypyrrole/Titanium Dioxide Composites

The development of ternary systems composed of conducting polymers, multi-walled carbon nanotubes (MWCNT), and metal oxides represents an important procedure in the optimization of electrical properties of electrodes to be applied as supercapacitors. Superior electrical properties obtained from electrical double-layer capacitance of CNTs and pseudo/redox capacitance of conducting polymer/metal oxides are associated with mechanical properties of CNT, high level of conductivity of polymer, and a reasonable homogeneous dispersion of metal oxide into the bulk of resulting composite. We have explored a low-cost composite of MWCNT/polypyrrole (PPy) and titanium dioxide (TiO2) in this work from which electrodes with a high level of conductivity are obtained as a result of a synergistic interaction between components.

Electrode of ionic polymer-metal composite sensors: Modeling and experimental investigation

In this study, we theoretically model and experimentally investigate the electrode electrical properties and the mechano-electrical properties of the ionic polymer-metal composite (IPMC) sensor. A physics-based model of the electrode was developed. In addition, based on the Poisson-Nernst-Planck system of equations, the current in the polymer membrane was modeled. By combining the physics of the polymer membrane and the electrode, the model of the surface electrical potential of the IPMC sensor was proposed. Experiments were conducted to test the electrical characteristics of the electrode and validate the model. The results demonstrate that the model can well describe the resistance, capacitance, and surface electrical potential of the IPMC electrode under external oscillation. Based on the model, a parametric study was done to investigate the impact of the parameters on the IPMC electrode properties. The results show that by changing the parameters of the electrode, such as the particle diameter, the electrode thickness, and microstructure, the electrical properties of the electrode can be changed accordingly. The current method of examining the electrode properties may also be applied to the study of electrodes for other smart materials.

A New Bacteriophage-Modified Piezoelectric Sensor for Rapid and Specific detection of Mycobacterium

Detection of tuberculosis and related diseases caused by mycobacteria is costly, time-consuming, and labor-intensive. Here a new phage-modified piezoelectric system for rapid and specific detection of mycobacteria was developed. In this system, interdigital gold electrode immobilized with lytic phage was used as a probe in place of a steel electrode in the multi-channel series piezoelectric quartz crystal (MSPQC) system. The probe was directly connected to the piezoelectric detection system. Mycobacterium was specifically captured to the phage-modified electrode and then lysed by immobilized phage, which caused the electrode electrical properties change. This change can be sensitively monitored by the piezoelectric detection system. The detection time of Mycobacterium smegmatis was less than 2 hours and a detection limit of 103cfu mL−1 was obtained. Additionally, it was successfully used to detect Mycobacterium tuberculosis. The developed system using phage-modified interdigital electrode showed high specificity and reproducibility for mycobacterium detection. Compared with the MSPQC system, the proposed system was faster and more specific.

Interconnection of Multichannel Polyimide Electrodes Using Anisotropic Conductive Films (ACFs) for Biomedical Applications

In this paper, we propose a method for interconnecting soft polyimide (PI) electrodes using anisotropic conductive films (ACFs). Reliable and automated bonding was achieved through development of a desktop thermocompressive bonding device that could simultaneously deliver appropriate temperatures and pressures to the interconnection area. The bonding conditions were optimized by changing the bonding temperature and bonding pressure. The electrical properties were characterized by measuring the contact resistance of the ACF bonding area, yielding a measure that was used to optimize the applied pressure and temperature. The optimal conditions consisted of applying a pressure of 4 kg f/cm(2) and a temperature of 180 °C for 20 s. Although ACF base bonding is widely used in industry (e.g., liquid crystal display manufacturing), this study constitutes the first trial of a biomedical application. We performed a preliminary in vivo biocompatibility investigation of ACF bonded area. Using the optimized temperature and pressure conditions, we interconnected a 40-channel PI multielectrode device for measuring electroencephalography (EEG) signals from the skulls of mice. The electrical properties of electrode were characterized by measuring the impedance. Finally, EEG signals were measured from the mice skulls using the fabricated devices to investigate suitability for application to biomedical devices.