Low Resistivity Values Research Articles

(Invited) Different Designs for Ta-Doped Llzo Based Solid State Battery Prepared By Tape-Casting

One pathway for moving forward from current Li-ion battery technology based on organic liquid electrolytes to next-generation battery design can be implementation of solid state electrolyte along with Li metal based negative electrode. This step would result in a battery with higher energy density and improved safety.One promising candidate material for ceramic electrolyte is garnet-type oxide LLZO (Li7La3Zr2O12) due to its relatively good chemical stability which allows relaxed requirements for processing and handling. Additionally, the doped LLZO has sufficiently good Li+ ionic conductivity (0.1 – 1 mS/cm at room temperature) and exhibits (electro-)chemical stability with the electrode materials currently under focus. To achieve low resistance values, the LLZO electrolyte needs to be prepared as a thin layer with high density. In order to integrate fabrication of LLZO electrolyte into industrial manufacturing, tape-casting can be considered as one of the low-cost scalable method for producing ceramic layers.In this study tape-casting was used to produce Ta-doped LLZO electrolyte layers with relative density of 98% and total conductivity of 0.3 mS/cm at room temperature. In order to obtain Li/LLZO/Li symmetrical cells, interfacial treatment was used for surface of LLZO to achieve good contact and low interfacial resistance with Li metal electrode. Current densities up to 300 µA/cm2 were achieved during galvanostatic cycling for flat LLZO pellet sample at 40 °C. The cell was galvanostatically cycled with high stability for long term at current density of 100 µA/cm2.Another design that can be considered for LLZO-based solid state battery is porous-dense-porous multilayers. This architecture has the advantage to provide support for electrolyte layer allowing to reduce its thickness and also increases the interfacial surface area which will reduce interfacial resistance. The described design allows to obtain lower resistance for the solid state battery with higher accessible current densities (>1mA/cm2), thus providing higher performance.

Hydrothermal Synthesis of a Graphene‐based Composite Enabling the Fabrication of a Current Collector‐free Microsupercapacitor with Improved Energy Storage Performance

AbstractHerein, the development and the characterization of an all‐solid‐state symmetrical and current collector‐free microsupercapacitor based on a new reduced graphene oxide‐polydopamine (rGO‐PDA) composite are reported. The rGO‐PDA composite is synthesized by a facile, eco‐friendly and scalable hydrothermal approach in the presence of dopamine which can not only contribute to the oxygen functional groups removal from graphene oxide but also polymerize onto the rGO sheets reducing their restacking and improving the wettability of the electrode. The optimized rGO‐PDA composite material exhibits excellent capacitance and cycling stability as well as an improved rate capability compared to the pristine rGO in Na2SO4 solution. This performance enhancement can be linked to the higher transfer kinetic and lower transfer resistance values of the ions involved in the charge storage process of rGO‐PDA, as determined by ac‐electrogravimetry. Furthermore, an all‐solid‐state microsupercapacitor was prepared employing the optimized rGO‐PDA composite as electrode material. Interdigitated electrodes were obtained thanks to a CO2 laser and a Na2SO4/PVA hydrogel was employed, no current collector was used. This device achieves a noteworthy energy density of 6.2 mWh ⋅ cm−3 at a power density of 0.22 W ⋅ cm−3. Moreover, it exhibits exceptional cycling stability, retaining 104 % of its initial capacity even after undergoing 10,000 cycles at 2 V ⋅ s−1.

Adjusting Ag deposition power to improve corrosion resistance of ITO/Ag/ITO film for gate driver on array

Gate Driver on Array (GOA) can fulfil narrow-frame full screen of display device, but may encounter through-hole burnout during operation due to electrochemical corrosion under high-temperature and high-humidity environments. Through-hole burnout originates from vapor that penetrates display sealant and invades signal-conducting through-hole in GOA, and results from action of electrochemistry and Joule heat. In this work, ITO/Ag/ITO films were deposited by direct current (DC) sputtering using ITO and Ag targets. This work attempts to reduce electrical resistivity, while limiting electrochemical corrosion of film by adjusting Ag deposition power. We found that high crystallinity and smooth morphology can inhibit vapor accumulation for Ag film prepared at a power of 8 kW, along with favorable sheet resistance and etching slope angle as low as 0.31 Ω/sq and 73.1°, respectively. Such film can run normally for 200 h in field test at a temperature of 85 °C and a humidity of 85 % with absence of through-hole corrosion. The outcomes of this work pave the way for industrial application of the narrow-frame full screen with virtues of both low resistance value and electrochemical corrosion resistance.

Electrical Resistivity - Tomography Studies In Determining Shallow Aquifer Potential Zones a Case Study in Different Terrains

The study documents the effectiveness of 2 D (Two Dimensional Electrical Resistivity Survey (Tomography) to map shallow subsurface geological formations namely recent Alluvium, Gondwana deposits and hard rock deposits. 2 dimensional Electrical Resistivity Survey (or tomography) was conducted at 2 locations at Valarpuram and one location Madurantakam areas. Gondwana deposits mask Valarpuram Thandalam, villages (at Kancheepuram District, Tamilnadu). To the east of Valarpuram alluvium thickness increases at shallow depths. Weathered and hard granitic gneiss and hard charnockite rocks overlie topsoil in Madurantakam areas (Chengalpettu District, Tamilandu). The survey was conducted to 12 m depth to decipher shallow permeable zones. Gondwana formations consisting of clays, siltstones are predominant in Valarpuram Thandalam and surrounding areas. Hard rock formations are found in Madurantakam areas. 2 Dimensional Resistivity Survey results indicate 2-D sections with very low resistivity values in the range of 2 to 4 ohm-m in Valarpuram Thandalam areas indicating predominant clay deposits with poor ground water potential. To the east of Valarpuram Thandalam resistivity data is of moderately higher value indicating sand deposits at shallow depths. These are ideal locations for dug wells. Low to moderate values at shallow depths indicating weathered thickness up to 12 m are observed at Madurantakam location. From 12m depth steep rise in resistivity values are observed in hard indicating presence of massive rock from 12m depth and below areas. Thus, 2 D Resistivity Imaging Technique are helpful in delineating shallow aquifer potential and this in turn helps in deciding the depth of open wells with high precision.

Delineating of Groundwater Aquifer Potential Using Vertical Electrical Sounding (VES) Methods in Giriloyo, Wukirsari Village, Imogiri District, Bantul Regency, Special Region of Yogyakarta

The geophysical investigation in Giriloyo, Wukirsari Village, has defined the groundwater potential zones. The research region underwent a geophysical examination utilizing the electrical resistance method, which comprised the vertical electrical sounding (VES) technique and the Schlumberger array system. The study area is surrounded by common rock types such as lava, tuff, agglomerate, and alluvial. In the study region, five lines were explored. Data for subsurface resistivity were gathered with an Oyo McOhm type 2115. IPI2win, a piece of computer software that analyzes data and automatically interprets apparent resistivity, was used to examine the data. The VES data showed the varied nature of the subsurface geological sequence. The geoelectrical cross-sections along the profile of (VES 2-3-4-1) show an aquifer, which stretches from the southeast towards the northwest part of the basin. Tuff is seen to have formed shallow aquifers due to the top weathered part at VES-2 and 3, while Quartz chlorite calcite (VES-4) and Plagioclases (VES-1) are devoid of shallow aquifers. The higher-elevation lithological areas recharge the low-elevation aquifer zones. At VES 2 and 3, relatively low resistivity values (< about 100 Ωm) have been observed. A field observation at these locations reveals that these lithologies are highly fractured with a weathering profile of up to 10 m. Thus, these are the sites where groundwater potential zones can be marked (figure 4). The high resistivity (about 3162 Ωm regions is observed extending at the VES-4; this may be due to the least weathered Quartz chlorite calcite at high elevation. VES-1 is also located on the plagioclase and shows a slight resistivity zone, which could be considered a groundwater recharge zone. This profile shows the high possibility of groundwater potential due to the zone of lineaments.

СОСТОЯНИЕ ДЫХАТЕЛЬНОЙ СИСТЕМЫ У ДЕТЕЙ С ГЕМОДИНАМИКОЙ ФОНТЕНА

Fontan procedure is a surgical operation for patients who were born with one working heart ventricle that involves complete separation of the pulmonary and the systemic circulation systems, which significantly improves their quality of life and becomes the preferred method of palliative surgery for congenital heart defects with univentricular hemodynamics. Despite all of its advantages this procedure is associated with a number of limitations dictated by the unique type of blood circulation. The uniqueness of Fontan hemodynamics lies in the fact that it is based on passive (non-pulsatile) pulmonary blood flow, which ensures gas exchange and preload of a single (systemic) ventricle. Pulmonary blood flow is determined by central venous pressure (CVP) and pulmonary vascular resistance. Therefore, systemic ventricular preload and cardiac output depend on well-running lung function coupled with low values of pulmonary vascular resistance. Various pulmonary anatomical or pathophysiological changes may compromise the optimal Fontan circulation. This bibliographical review represents currently known data on cardiopulmonary interactions within Fontan circulation, the causes for and the variants of the pulmonary dysfunction.

Terahertz bow-tie diode based on asymmetrically shaped AlGaN/GaN heterostructures

Asymmetrical shaping of AlGaN/GaN heterostructures containing a conductive layer of two-dimensional electron gas (2DEG) was used for the development of bow-tie (BT) diodes for room temperature terahertz (THz) detection. Considering operation of the THz BT diode in the unbiased mode as preferable for practical applications, we investigated the diodes with an obvious asymmetry of IV characteristics, which was found to be more pronounced with the decrease of an apex width, resulting in the sensitive THz detection. A nonuniform heating of carriers in a metalized leaf of the BT diode was attributed as the main mechanism that caused the rectification of THz waves. The responsivity and noise-equivalent power (NEP) at the fundamental antenna frequency of 150 GHz were up to 4 V/W and 2 nW/√Hz, respectively. Such high sensitivity of BT diodes allowed us to measure for the first time the response spectrum of the asymmetric BT antenna demonstrating fundamental and higher order resonances in good agreement with finite-difference time-domain simulation data in a broad spectrum range. The detailed investigation of the lowand high-frequency noise characteristics of AlGaN/GaN BT diodes revealed that only thermal noise needs to be considered for the unbiased operation, the value of which was relatively low due to a high density of 2DEG enabling low resistivity values. Moreover, we observed that the responsivity of BT diode scales with its resistance, revealing that tapering of the diode apex below a few microns could be ineffective in applications which require low NEP values.

Three-dimensional Magnetotelluric Inversion and Magnetic for The Characterization of The Geothermal Field Reservoir Zone “X”

Geothermal as an alternative energy source that is renewable and environmentally friendly has an important role in providing domestic energy needs. Exploration is one of the most important stages in the development of geothermal energy because it can minimize the risk at the stage of exploitation and development. Geophysical methods such as geomagnet and magnetotelluric are one of the methods used in exploration. Magnetic method can provide information on the description of rock demagnetization due to the presence of heat source. However, the magnetotelluric method will provide information about rock type resistance on geothermal fields. The existence of heat source using the geomagnetic method is represented by a low anomaly value as an indication of demagnetized rocks. The results of 3D inversion processing show a low value of type resistance in the area and form an updome. The correlation of the two results of processing the data can be seen in the southern part of the "X" geothermal field research area. Based on 3D Inversion modeling it can be seen the depth of the "X" Base of Conductor (BOC) geothermal system ranges from 1000 m to -800 m with resistivity ≤ 10 Ωm which is suspected as volcanic rocks. Geothermal reservoir is at a depth of 1000 m to -2000 m with a moderate resistivity of 40 - 60 Ωm which is suspected as an andesite volcanic rock, with temperature estimates ranging from 218o C to 255o C.

Comparative electrochemical properties of polyaniline/carbon quantum dots nanocomposites modified screen-printed carbon and gold electrodes

In this study, carbon quantum dots (Cdots) synthesized from a pencil graphite precursor using a bottom-up method were incorporated into polyaniline (PANI) to form Cdots-PANI nanocomposite. Cdots, PANI and Cdots-PANI nanocomposites were characterized using the Fourier-Transform infrared spectroscopy (FT-IR), UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The FT-IR spectra of graphene and Cdots show the emergence of a peak at 3500 cm−1, which was initially absent in graphene, after the formation of Cdots, among other peaks. The peak at 3500 cm−1 and the stretching vibration at 1647 cm−1 suggest the presence of –OH and C=C in the Cdots. The FT-IR spectra of PANI/Cdots and PANI show that the peaks in PANI shifted to higher wavenumbers after composite formation. Similarly, the UV–visible spectra of the PANI/Cdots composite revealed a hypsochromic shift of the characteristic PANI peaks at 320 and 600 nm to 300 and 560 nm, respectively. Electrochemical characterization of Cdots, PANI and Cdots-PANI nanocomposites was done with screen-printed carbon electrodes (SPCE) and screen-printed gold electrodes (SPAuE) modified with the nanomaterials and the nanocomposites. The electrochemical properties of the as-synthesized nanomaterials and the nanocomposite were investigated with Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) in 10 mM K3[Fe(CN)6] solution using the bare screen-printed electrodes and the modified electrodes. The modified electrodes gave higher anodic peak current (Ipa) responses and lower charge transfer resistance (Rct) values in the redox probe than the bare electrodes. The SPCE-Cdots-PANI nanocomposite-modified electrode exhibited better redox potentials, faster electron transfer kinetics, larger surface area, and greater stability than the bare electrodes and the other modified electrodes. The outstanding electrochemical properties of SPCE-Cdots/PANI underscores its potentials as a sensitive electrochemical sensor for a wide range of analytes.

Enhancing surface area, morphology, and electrocatalytic activity favouring triiodide reduction via surface sulfurization of metal oxide

Herein, a direct anionic exchange method was employed using Thioacetamide (TAA) and Phosphorous Pentasulfide (P2S5) by facile hydrothermal method. The preliminary results confirm that the sulfurization leads to amorphization and formation of MoS2. BET analysis demonstrates the substantial improvement in the surface area from 72.046 m²/g for pristine MoO3 to 104.402 m²/g, and 140.802 m²/g, for TAA and P2S5 treated MoO3 respectively, was achieved upon sulfurization. Cyclic Voltammetry (CV) studies show an excellent triiodide reduction ability in LiI/I redox system which is due to the improvement in electrocatalytically active sites and stability across the CE/electrolyte interface. The lower charge transfer resistance (Rct) values obtained from Electrochemical impedance spectroscopy (EIS) confirm the effective charge carrier transport that improved the conductivity across electrode/electrolyte interface. The power conversion efficiency (PCE) measured under our lab conditions found an improvement for pristine MoO3 i.e. 0.78% to a maximum PCE of 5.48% and 4.12% for the P2S5 and TAA sulfurized MoO3 respectively. In general, this work highlights the use of phosphorous pentasulfide which can also be utilized for direct anionic exchange with the advantage of phosphorous content in resultant products which could greatly improve various physio-chemical properties of the material.

Detection of Seepage Paths in Dam by Electrical Resistivity Tomography

The stability of the dam can be compromised by water erosion and seepage, which primarily affect the resistivity distribution underground. Seepage pathways in the dam are detected through electrical resistivity tomography (ERT), utilizing variations in resistivity for delineation. The 2D profiles show that the resistivity structure of the dam is relatively higher resistivity values (100~400Ωm), while the seepage paths exhibit significantly lower resistivity values (10–50 Ω m). it can outline five seepage paths.

Fabrication of easily separated biochar balls and their catalytic mechanism for PMS

In this work, N-doped biochar balls NBC3800 were prepared from waste biomass corn straw. The biochar balls supported by clay have an obvious spherical structure. Clay can enhance the adsorption capacity of the biochar balls to pollutants by its excellent adsorption property. Thus, the clay can speed up the catalytic reaction by strengthening the adsorption function. The biochar balls NBC3800 have the best catalytic performance and the removal rate of NC can reach 100% within 100 min. The electron transfer resistance of NBC3800 is only 36 Ω indicating a lower resistance value and higher conductivity to transfer electrons compared with carbon nanotube. Electron paramagnetic resonance (EPR) and electrochemical analysis show that sulfate radical (SO4•−), hydroxyl radical (·OH), singlet oxygen (1O2), and electron transfer are all involved in the reaction. The removal rate of NC can still be maintained at 83.41% after being reused five times. Besides, it can be further improved to 100% by high temperature regeneration at 800 ℃. Most importantly, the biochar balls can be separated from the solution very easily which not only extremely improves the recyclability but also avoids secondary pollution to the water body.

Integrated geophysical methods used to explore geothermal potential areas in Siogung-Ogung, North Sumatra, Indonesia

The manifestations of some hot springs in Siogung-Ogung, North Sumatra, Indonesia have increased speculation of likely geothermal sources. Therefore, integrated geochemical and geophysical methods were employed to identify the geothermal prospect of the area. Two-dimensional electrical resistivity and geomagnetic methods were used for the geophysical survey. The geochemical survey used three concentration measurements: geothermometer silica (SiO2), geothermometer Na-K, and geothermometer Na-K-Ca. A Wenner Schlumberger array with a 5-meter electrode spacing was used to acquire the 2-D resistivity data, which was processed using Res2Dinv software. The geomagnetic method was performed with a proton precession magnetometer, and the data were processed using Surfer to produce the magnetic residual map. The 2-D electrical resistivity results show that the area has low resistivity values (1-700 Ωm). The resistivity values from 1 to 100 Ωm could be due to the presence of hot waters in alluvium, and the resistivity values > 400 indicate andesite rock, which can function as a hot water conductor from the source. The magnetic residual map shows geomagnetic values from 150 nT to 360 nT, which infer the potentiality of geothermal within the study area. The geochemical results show that the reservoir temperature is 572 °C. Based on the integrated results, the study area has promising geothermal potential.

β-Cyclodextrin-Stabilized CuO/MXene Nanocomposite as an Electrode Material for High-Performance Supercapacitors.

Supercapacitors are the best energy storage systems due to their high power density, quick charge/discharge rate, and long-term reliability. In this study, β-cyclodextrin-stabilized CuO nanoparticles (CuO@βCD NPs) were synthesized through a simple reduction method and anchored on the surface of MXene nanosheets in three different proportions (1:1, 4:1, and 1:4) to obtain CuO@βCD/MXene nanocomposites through the wet-impregnation method. The formation of CuO@βCD NPs and their physicochemical characteristics were verified by XRD, XPS, FE-SEM, and HR-TEM analysis. The actual focus is on the evaluation of the electrochemical performances of CuO@βCD, MXene, and CuO@βCD/MXene nanocomposites for supercapacitor applications. The cyclic voltammetry and galvanostatic charge-discharge analysis revealed the pseudocapacitance and an improved specific capacitance of 1693.43 F g-1 at 0.90 A g-1 for the CuO@βCD/MXene (1:1) nanocomposite. The electrochemical impedance analysis displays superior electrical conductivity with a low charge transfer resistance value on incorporating CuO@βCD between the MXene layers. Furthermore, the CuO@βCD/MXene (1:1) nanocomposite exhibited improved long-term cycling stability by retaining 86% of its initial specific capacitance even after the 10,000th cycle at the current density of 4.54 A g-1. Based on the electrochemical performance, the CuO@βCD/MXene (1:1) nanocomposite proves its suitability as an electrode material for supercapacitor application with long-term cycling stability and rate capability.

Delineation of Subsurface Migration Pathways of Petroleum Contaminants in Ikarama, Okordia Clan of Bayelsa State, Nigeria

One well-known cause of groundwater contamination in developing nations that produce oil is oil leaks. Oil leaks are typically caused by a variety of circumstances, such as inadequate management and upkeep of oil facilities, equipment failure, and pipeline vandalism by oil criminals. This research evaluates the movement of underground oil contaminants in an oil production field at the Okordia clan's Ikarama hamlet in the Yenagoa Local Government Area in the state of Bayelsa. Schlumberger array was utilized in order to apply the electrical resistivity tomography technique along three (3) VES surrounding the oil spill spot. Values for resistivity were found. In the locations under study, three (3) vertical electrical soundings (VES) were conducted. Comparison of theoretical soil resistivity to measured fluid resistivity for various caption exchange Values of capacity have been researched. The resistivity values, when reversed, ranged from 0.17 m to 146.8 m. The hydrocarbon contamination (oil plumes) is the cause of the high resistivity values (21.54 – 146.8 Ωm) and the low resistivity values (0.1–15.8 Ωm). The 2D resistivity approach is an effective tool for examining pollution caused by hydrocarbon in a coastal environment, as this study has proven.

Caprock integrity at Çanakkale-Tuzla hydrothermal system inferred from magnetotelluric modeling using particle swarm optimization

The impermeable caprock within a geothermal system serves the purpose of effectively sealing the reservoir, resulting in the elevation of both pressure and temperature. This sealing mechanism plays a crucial role in the long-term preservation of the system, while also contributing to its overall sustainability. Caprock failure subsequent to seismic activity near a geothermal site can lead to the permeation of the caprock structure, resulting in diminished sealing capabilities and a decline in the reservoir temperature. Additionally, this process alters the geochemical composition of the water by creating a hydrothermal mixture zone that disrupts the resistivity structure of the caprock, which is typically characterized by low resistivity values due to its substantial clay content and mineral alteration. This study focuses on investigating the integrity of the caprock at ơnakkale-Tuzla geothermal field in Turkey, where the water temperature and conductivity were reported to have decreased after a moderate magnitude earthquake and subsequent aftershocks. For this purpose, we performed magnetotelluric (MT) measurements, a method known for its sensitivity to geochemical reactions. These measurements were conducted along two parallel profiles that encompassed a total of 32 stations. Particle swarm optimization (PSO) technique was employed to overcome subtle difficulties associated with conventional inversion methods when modeling the MT data of complex formations. This is the first study that overcomes the difficulties emanating from the caprock failure by modeling MT data using PSO. Our modeling approach produced resistivity images that we interpreted as the signature of the failed caprock following the earthquake at the study site. Our results appear to confirm the documented geochemical changes or hydrothermal mixture zone about caprock structure.

Carbon nanotube/castor oil‐based waterborne polyurethane films with gradient structure for absorption‐dominated electromagnetic interference shielding and Joule heating

AbstractConductive polymer composites are highly demanded for practical application in electromagnetic interference shielding and Joule heating owing to their excellent flexibility and adjustable conductivity. Herein, a thin film with a gradient structure, comprising carbon nanotube/castor oil‐based waterborne polyurethane (CNT/WPU), has been fabricated through solution mixing utilizing casting technology. Scanning electron microscopy images confirm that CNTs are enriched at the top of the obtained CNT/WPU film, leading to a low resistance value. Consequently, the resultant gradient CNT/WPU films exhibit shielding effectiveness, specific shielding effectiveness, and an absorption coefficient of 22.8 dB, 1091 dB/cm, and 0.697, respectively, indicating a predominance of absorption in the shielding capacity. The temperature at the surface of the resultant gradient CNT/WPU film reaches ~77°C at a voltage of 20 V. The film with a CNT content of 14.1 wt% exhibits a good stress of 11.7 MPa and a high module of 39.9 MPa. Therefore, the obtained CNT/WPU films can be applied as thin shielding materials or coating.Highlights Fabricating a gradient CNT/castor oil–based waterborne polyurethane films. Exhibiting shielding effectiveness of 22.8 dB and A‐value of 0.697. Steady‐state temperature of CNT/WPU reaches 77°C at 20 V. Possessing green EMI shielding capability.

Improved performance in asymmetric supercapacitors using SnO2–MoS2 composite microspheres

This paper reported the facile synthesis of SnO2, MoS2, and SnO2−MoS2 composite material via sol-gel method with ex-situ hydrothermal method and utilized for supercapacitor applications. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis confirmed the structural and morphological features. At the same time, the electrochemical performance was analyzed by CV, CD, and well-known impedance analysis via a Nyquist plot in three-electrode assembly in KOH solution. The outcomes from the three-electrode assembly demonstrated that the SnO2−MoS2 composite material yields a high capacitance value of 415 F/g than pure SnO2 and MoS2 electrodes with the lowest resistance values, indicating the fast transportation of ions during the electrochemical process. Inspired by the optimized performance of SnO2−MoS2 composite material, an asymmetric supercapacitor was further developed with GO (graphene oxide) severed as the negative electrode and symbolized as “SnO2−MoS2||GO–KOH asymmetric supercapacitor” in aqueous solution as the electrolyte. Remarkably, a high output voltage of 1.6 V was realized coupled with a high capacitance of 102 F/g, which can be attributed to the combined energy storage performance of pseudocapacitive, and double-layer capacitance arises from SnO2−MoS2 and graphene oxide (GO), respectively. Moreover, a high specific energy of 32 Wh/kg at a maximum specific power of 5520 W/kg was achieved at excellent cycling stability of 92.2 % capacitance retention after 5000 cycles at 10 A/g. Therefore, we summarize that metal oxide can composite with metal oxide, and graphene oxide (GO) collectively boosts the overall performance of high-performance supercapacitors.

Effect of Process Pressure on Carbon-Based Thin Films Deposited by Cathodic Arc on Stainless Steel for Bipolar Plates

In this study, three carbon-based coating variants were deposited onto stainless steel substrates, and the process pressure during the carbon layer deposition was varied. We conducted Raman spectroscopy, transmission electron microscopy, interfacial contact resistance measurements, and potentiodynamic polarization tests to examine the effect of the process pressure on the properties of the coatings. The structural characterization revealed that all specimens exhibit a highly sp2-bonded structure. However, some structural differences could also be identified. In the TEM cross-section images of the carbon layer variants, these structural differences could be observed. The carbon layer deposited at 0.98 Pa has some distortions in the mainly perpendicular graphitic structure, which agrees with the Raman results. Almost completely vertically oriented graphitic layers exhibit the 0.1 Pa coating variant with a d-spacing similar to pure graphite. Regarding the contact resistance, the process pressure has only minor influence. All coatings variants have very low resistance values below 3 mΩ cm2, even at a compaction force of 50 N cm−2, which can be attributed to the graphite-like structure. The polarization tests show that the corrosion resistance increases with increasing process pressure. The best coating variant has a corrosion current density of approximately 10−8 A cm−2 and almost 10−6 A cm−2 at room temperature and 80 °C, respectively.

Superior Conductivity of Transparent ZnO/MoS2 Composite Films for Optoelectronic and Solar Cell Applications.

The use of transparent conductive oxides in optoelectronics created a revolution where new-generation materials with high transmittance, low sheet resistance values, durability, and portability can be achieved without decreasing efficiency or increasing costs. Transparent ZnO/MoS2 sandwich-structured conductive composite films were produced in this study via the sol-gel method, which is considered the most efficient method due to its simple process and low cost. The crystal structure properties of ZnO/MoS2 were characterized via X-ray diffraction (XRD) patterns. The crystal sizes of ZnO films doped with different amounts of MoS2 were determined. A UV-visible absorption spectrometer was used to perform the spectroscopic analysis of the film. The area under the absorption curve and the full width of the half-maxima of absorbance data were calculated. Using these values, the optimum amount of MoS2 was determined for the best additive distribution. In addition, in order to determine the best transparent conductive material, resistance values measured via the four-point probe method were compared for different MoS2 additive amounts. The optical and electrical characterizations of transparent ZnO/MoS2 conductive oxide films were investigated. According to the parameters obtained via UV-vis spectroscopy, XRD, and four-point probe measurements, the most effective dispersion that exhibits a low width ratio and high resonance ratio was found for ZnO/MoS2 with a doping amount of 4 mg, the crystallite size of the films was found to be within the range of 21.5 and 24.6 nm, and these observations demonstrated a figure-of-merit value of more than 4.8 × 10-2 with respect to these sandwich-structured films. Compared to the values of previous studies on various transparent ZnO-doped conductive oxide materials, it is possible to claim that these new films have a structure that is very similar to the transparent conductivity characteristics of other films, and they may even be superior relative to some MoS2 amounts.