Electronic Conductivity Measurements Research Articles

Enhanced electrochemical performance of garnet Li7La3Zr2O12 electrolyte by efficient incorporation of LiCl

Garnet-type Ta-doped Li7La3Zr2O12 (LLZO) lithium-ion-conducting ceramic electrolytes has become the promising and critical candidate for developing the high-energy-density all-solid-state lithium batteries, due to the satisfied Li+ conductivity, stability against metallic lithium anode, and the feasible preparation under ambient air. Here, to further increase the lithium-ion conductivity of LLZO comparable to that of the commercial organic liquid electrolytes, lithium chloride (LiCl) is effectively introduced to synthesize the garnet-type ceramic electrolytes with the nominal composition (Li6.5La3Zr1.5Ta0.5O12)1-x–(LiCl)x (x = 0, 5mol%, 10mol%, 15mol%, 20mol%, and 25mol%) via high-temperature calcination process. The cubic structure with highly conductive performance is confirmed from X-ray diffraction measurement as well as Raman spectra analysis. Structural information is observed according to field emission scanning electron microscope equipped with energy dispersive spectrometer and density measurements. Among above investigated ceramic compositions, the prepared (Li6.5La3Zr1.5Ta0.5O12)0.85–(LiCl)0.15 ceramic electrolyte sheet sintered at 1200 °C for 12h presents the room-temperature Li-ion conductivity of 1.22 × 10−3 S·cm−1 by alternating current (AC) impedance analysis along with the corresponding activation energy of 0.262eV through Arrhenius equation calculation. The electronic conductivity measurements are also done by direct-current polarization to confirm the ionic nature for all investigated ceramics. Furthermore, the Li|(Li6.5La3Zr1.5Ta0.5O12)0.85–(LiCl)0.15 |Li symmetric batteries can possess the small interfacial resistance of 92.3 Ω cm2 and stably run for 1000 h at 0.1 mA cm−2 without a short circuit at room temperature. The hybridized lithium-sulfur battery with (Li6.5La3Zr1.5Ta0.5O12)0.85–(LiCl)0.15 electrolyte delivered excellent initial room-temperature discharge capacity of 1204mAh·g−1 and 1152 mAh·g−1 under the current density of 0.1C and 0.2C respectively, large coulombic efficiency, and great cycling stability. Moreover, the lithium-sulfur batteries also can show excellent cycling performances under different current densities and a good capacity recoverability. The above investigation results suggest that the low-melting-point LiCl incorporation in Li6.5La3Zr1.5Ta0.5O12 electrolyte is an effective measurement to synthesize the cubic and dense Li-stuff garnet ceramic sheets for the high-performance rechargeable next-generation solid-state batteries.

(Invited) From Electronic Conductivity Measurement to Its Role on Oxygen Electrode Delamination Phenomena: A Brief Review

Over the past few decades, degradation and stability of SOEC has been a major concern for long term applications. Numerous factors such as cell fabrication, materials selection including both cell components and metallic interconnects, operation voltage and current density, working temperatures, gas compositions, stacking techniques, etc., can all affect the stability. While seemingly it is challenging to separately identify and determine the contribution of each factor, delamination of oxygen electrode was reported as one of the main reasons for this degradation or failure [1-3]. Theoretical analyses, particularly by Anil Virkar, have shown that the actual oxygen chemical potential inside the electrolyte can be well above or below the corresponding values at the two electrodes in a SOEC when using predominantly oxygen ionic conducting membranes, leading to either delamination at oxygen electrode or electro-reduction near the fuel electrode [4-6]. Therefore, it is critical to measure electronic conductivity in the electrolytes.Meanwhile measurement of electronic conductivity in MIEC is typically done by the classical Hebb-Wagner (H-W) polarization method[7, 8]. Over the past decades, it has been realized that the H-W method has some critical limitations or issues that may limit its accuracy or testing feasibility, such as relatively long relaxation time towards steady state, challenges on sealing, violation of true ionic blocking and possible interaction with gas phases. A few modified versions of H-W techniques and also non-H-W type techniques on electronic conductivity measurement have been reported and investigated[9-12] . In this report, a brief review is given to cover both of these topics.

(Keynote) Experimental and Computational Insights into Electronic Structure and Redox Properties of Bare and Doped Co3O4 Nanocrystals of Euhedral Morphology and Their Heterojunctions with Alien Oxides and Carbon Materials

One of the most attractive oxide materials with remarkable record of widespread applications are cobalt spinels and their derivatives obtained by doping with alien redox (3dn) and nonredox (Li) cations or via hybridization with other oxides (CeO2, TiO2, a-Al2O3) or carbon support. They have recently received a great deal of theoretical and practical attention because of an outstanding activity in many redox processes important for photo/electro/catalysis. Among many potential applications, their relevance as promising substitutes for platinum in oxygen reduction reaction (ORR) or oxygen evolution reaction (OER) can be mentioned, in particular. The properties of nanostructured cobalt spinel materials depend on their size, shape, doping and interfacing features. In this context, euhedral spinel nanocrystals that expose well defined crystallographic planes, allow for sensible investigations into establishment of the surface/bulk structure-redox reactivity relationships in real conditions.In this presentation application of S/TEM and inverse Wulff hull matching techniques supported by image simulation was discussed for elucidation the mechanism of hydrothermal synthesis of euhedral cobalt spinel nanocrystals the their shape retrieving. Periodic spin unrestricted DFT-PW91+U and hybrid DFT/HSE06 calculations were applied for modeling the morphology, structure and electronic properties (DOS structure) relevant for redox behavior of bare and doped cobalt spinel nanocrystals. The results allowed for thorough characterization of the structure and reconstruction of the exposed low index (100), (110), and (111) planes, and explain the influence of dopants. The effect of the valence state of lithium (Li+ or Li0), and its locus on the valence pining of the cobalt cations was determined. DFT calculations together with the ab initio thermodynamic modeling were used to study the electronic structure of the created defects, and stability of different terminations of cobalt spinel and Li-doped Co3O4 under various redox conditions. The associated electronic and spin relaxation processes were discussed as well. For the most stable stoichiometric (100) and (111) facets, the surface redox state diagrams in a wide stoichiometry range were constructed, and analyzed in detail. Intrinsic charge transfer processes involving electron (n-conductivity) and hole (p-conductivity) transfer between the octahedral and tetrahedral cobalt cations were modeled using a small polaron approximation (Marcus-Dupuis model). Formation of n-p junctions (Co3O4|CeO2, Li-Co3O4|CeO2) and MxCo3-xO4/carbon hybrids were analyzed by S/TEM, XPS spectroscopy (band alignment), contactless electronic conductivity and work function measurements, corroborated by DFT modeling. The redox properties of the interface and spinel faceting, and the role of electric conductivity and the nature of the carbon support functional groups were discussed in the context of the ORR, OER performance, and catalytic redox reactivity (activation of O2).AcknowledgmentsS.W. thanks for the financial support of the project “High-performance electrocatalyst for oxygen reduction reaction with low platinum content” carried on within the Program “Pearls of Science” of the Ministry of Education and Science of Poland.

Synthesis and Application of Polypyrrole/DBSA/Boron Nitride Ternary Composite as a Potential Chemical Sensor for Ammonia Gas Detection

The present study demonstrates the self-assembly method of chemical oxidative polymerization of polypyrrole (PPy), polypyrrole/boron nitride (PPy/BN), and polypyrrole/dodecylbenzene sulfonic acid/boron nitride (PPy/DBSA/BN) thin films for ammonia (NH3) gas detection. The PPy, PPy/BN, and PPy/DBSA/BN thin films were comprehensively characterized using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), X-ray diffractometry (XRD) and conductivity measurement. ATR-FTIR revealed all the pertinent peaks of PPy, BN, and DBSA present in the PPy/DBSA/BN. SEM images of PPy/DBSA/BN depict well-organized morphology. PPy/DBSA/BN recorded the highest conductivity of 4.771 x 10-6 S cm-1 among the prepared polymer thin films. The obtained characterization results are in good agreement with the NH3 gas sensor measurements conducted on the PPy/DBSA/BN composite. The linear correlation coefficient between the two was found to be R2 = 0.9916, indicating a strong relationship. Furthermore, the PPy/DBSA/BN thin film demonstrated a low limit of detection (LOD) of 5.8 ppm, surpassing the OSHA threshold value for NH3 gas. This suggests that the sensor is highly sensitive to trace amounts of NH3 gas. Moreover, the PPy/DBSA/BN thin film exhibited exceptional reusability, with the ability to be used for up to 10 cycles without a significant decrease in performance. The sensor also demonstrated selectivity towards NH3 gas in the presence of common interfering species. Additionally, it exhibited long-term stability, maintaining its performance over a period of 7 days. The proposed self-assembled gas sensor has showcased remarkable performance in detecting NH3 gas at room temperature, making it a promising candidate for industrial applications.

Analysis of the intermediate states of an electrode slurry by electronic conductivity measurements

Analysis of the intermediate states of an electrode slurry by electronic conductivity measurements

Effect of flux activator in reflow process related flux residue on the climatic reliability of surface-mount electronic devices

This paper investigated the effect of flux activator used in reflow flux formulation on the electrochemical reliability of electronic devices. The focuses were placed on the perspective of surface insulation resistance (SIR), cleanliness, and its morphology transformation and redistribution behavior of flux residue under climatic exposure. Standardized accelerated climatic test on SIR comb-structure pattern was performed to benchmark the humidity interaction of the tested flux formulations used in solder paste. The influence of stand-off height for the surface-mount component on the humidity robustness was analyzed using an in-house designed dummy test rig and electrochemical impedance spectroscopy. Scanning electron microscopy and conductivity measurement was used to understand the hydrolytic degradation of the flux residue and the release of the conductive ionic residues during climatic exposure. Results indicate the spreading area and the hydrolytic degradation behavior of the flux residue were influenced by the type of flux activators used in flux formulation. The climatic reliability was influenced by the combined effect of the aggressiveness of flux activator and the spreading of the flux residue. However, result also shows that the climatic reliability of the surface-mount device can be improved by increasing the stand-off height of the components together with selected flux formulation.

Measurement of electronic conductivity in mixed ionic and electronic conductor (MIEC) via a novel embedded microcontact method

Electronic conductivity plays an important role on the performance and durability of energy devices containing mixed ionic and electronic conductors (MIEC). Over the past decades, it has been realized that the classical Hebb-Wagner(H-W) method has some critical limitations or issues that may limit its accuracy or testing feasibility, such as relatively long relaxation time towards steady state and challenges on sealing. In this study, we reported an embedded microcontact ionic blocking electrode to minimize these issues. Using this method, the activation energy in Ce0.9Gd0.1O1.95 (GDC10) are measured, respectively as, 2.51 and 1.44 eV, for n type electronic and p type hole conductivity. The values are similar to those reported in literature as 2.51 and 1.45 eV, respectively, for n and p type conduction also in GDC10 via non-embedded ionic-blocking electrode. At a refence oxygen partial pressure of 0.21 atm, the n type conductivity, σe(0), is obtained as 1.05×10−7, 2.81×10−6, 4.28×10−5 S cm−1 at 600, 700, and 800 °C, respectively, and the p type conductivity, σh(0), is obtained as 1.18×10−4, 5.86×10−4, 3.51×10−3 S cm−1 at 600, 700, and 800 °C, respectively. The new method could be an effective technique to determine electronic conduction in other MIECs.

Triazole based Schiff bases and their oxovanadium(IV) complexes: Synthesis, characterization, antibacterial assay, and computational assessments

The synthesis and characterization of two new Schiff base ligands containing 1,2,4-triazole moieties and their oxovanadium(IV) complexes have been reported. The ligands and their complexes were studied by ultraviolet–visible (UV–Vis), Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), electron paramagnetic resonance (EPR), X-ray diffraction (XRD), conductivity measurement, cyclic voltammetry (CV), and elemental analyses. The molar conductance of oxovanadium(IV) complexes were found to be relatively low, depicting their non-electrolytic nature. The XRD patterns reveal the size of particles to be 47.53 nm and 26.28 nm for the two complexes in the monoclinic crystal system. The molecular structures, geometrical parameters, chemical reactivity, stability, and frontier molecular orbital pictures were determined by density functional theory (DFT) calculations. The theoretical vibrational frequencies and EPR g-factors (1.98) were found to correlate well with the experimental values. A distorted square pyramidal geometry with C2 symmetry of the complexes has been proposed from experimental and theoretical results in a synergistic manner. The antimicrobial sensitivity of the ligands and their metal complexes assayed in vitro against four bacterial pathogens viz. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Salmonella Typhi showed that the oxovanadium(IV) complexes are slightly stronger antibacterial agents than their corresponding Schiff base precursors. The binding affinities obtained from the molecular docking calculations with the receptor proteins of bacterial strains (2EUG, 3UWZ, 4GVF, and 4JVD) showed that the Schiff bases and their oxovanadium(IV) complexes have considerable capacity inferring activeness for effective inhibition. The molecular dynamics simulation of a protein-ligand (4JVD-HL2) complex with the best binding affinity of −12.8 kcal/mol for 100 ns showed acceptable stability of the docked pose and binding free energy of −15.17 ± 2.29 kcal/mol from molecular mechanics-generalized Born surface area (MM-GBSA) calculations indicated spontaneity of the reaction. The outcome of the research shows the complementary role of computational methods in material characterization and provides an interesting avenue to pursue for exploring new triazole based Schiff's bases and their vanadium compounds for better properties.

Impedance modeling for excluding contact resistance from cross-plane electronic conductivity measurement of anisotropic two-dimensional Ti3C2Tx MXenes

We propose impedance spectroscopy modeling as a convenient tool for estimating the cross-plane conductivity of anisotropic two-dimensional materials by excluding contact resistance with the underlying metal electrodes. We showcase this idea on two types of titanium carbide Ti3C2Tx MXenes, wherein Tx represents surface functional termination. These MXenes are synthesized from the same parent MAX phase material (Ti3AlC2) by different synthesis protocols and are studied in their plain as-synthesized states as well as after short annealing. The cross-plane conductivity of MXenes estimated by our approach appears to be up to an order of magnitude higher than is estimated by a conventional one. We validate our impedance modeling approach by comparing the specific contact resistance results derived from it to a direct estimation by transmission line measurement. We also deduce which functional group has a dominant footprint on the conductivity in each studied MXene by performing numerical simulations on cross-plane conductivity as well as on electronic band structures. The novel equivalent circuit developed herein may be extended to other anisotropic thin films to aid their application in various electronic devices.

Li4Ti5O12-Hard carbon composite anode for fast-charging Li-Ion batteries

The fast charge of lithium-ion batteries (LIBs) needs anode and cathode materials operating at high current densities and thus require special consideration for the electrode materials. This work studies the effect of the loading ratio of Hard Carbon (HC) and Li4Ti5O12 (LTO) on the electrochemical behavior of fast-charging LIBs. The formation of LTO/HC composites is confirmed with structural characterizations and electronic conductivity measurement. Galvanostatic charge–discharge cycling testing shows that superior cycling stability and specific capacity are achieved for the LTO/HC composite electrode with 20 wt% HC (LTO-HC20). Electrochemical impedance spectroscopy study reveals the improved lithium diffusion coefficient of LTO-HC compared to LTO only. Post-mortem analysis suggests that the LTO-HC composite electrodes, with an optimized LTO to HC ratio, can effectively contribute to improved Li-ion storage and electronic conductivity and robust solid electrolyte interphase on the electrode surface. Finally, full cells consisting of the optimized anode (LTO-HC20) and cathode (NMC 333) are fabricated and evaluated. It is found that a full cell of NCM/LTO-HC20 exhibits capacity retention of 82% and 79% over 300 cycles and specific energy of 130 and 89 Wh kg−1 at 1C and 3C, respectively. Therefore, a specific ratio of HC in the LTO-HC composite anode can dramatically improve the battery performance and specific energy while reducing the cost.

Integrated Thermo-Electric Measurement of Electrospun Nanofiber for Polymer Electrolyte Fuel Cell

Polymer electrolyte fuel cell (PEFC), as an efficient hydrogen energy conversion device, has been developed for decades. Catalyst layer (CL), where the oxygen reduction reaction occurs, predominantly determines the performance of PEFC. Since 1889, the mass activity of catalyst layer has been improved for more than three orders of magnitudes, thanks to the invention of PFSA ionomer and highly dispersed catalyst on nano-sized carbon support. In recent years, introducing order into CL is bringing the CL performance to a higher level. The CLs with state-of-the-art performance feature nanofiber structures. One type of is ionomer nanofibers deposited with Pt/C catalyst on the surface, and another type is composite nanofiber containing ionomer, Pt/C catalyst, and binding polymer. Their superior performance may come from the ordered mass transport network and the size effect of nanofiber conductivity. To further improve the CL performance, the structure-property-performance relationship of ionomer nanofibers or composite nanofibers needs to be clarified.In this work, we designed a setup to measure the proton, electron and thermal conductivity as well as the performance of a single ionomer or composite nanofiber. We developed a self-bonding method to fix the nanofiber on the micro-electrode. For proton and electron conductivity measurement, four-probe method was adopted to eliminate the electrical contact resistance and interfacial effect. For thermal conductivity measurement, Raman assisted steady state method was used to directly measure the temperature profile along the nanofiber. So, the measurement error resulting from the thermal contact resistance between the sample and the temperature sensor/heat sink can be eliminated. For performance measurement, three-electrode system was adopted using the Ag/AgCl electrode as the reference electrode and the Zn/ZnCl2 electrode as the counter electrode. We prepared nanofibers with different size, polymer content, and cross-sectional component distribution by controlling the ink recipe and electrospinning parameters. The integrated thermo-electric measurement found that the proton and thermal conductivity of nanofiber are one order of magnitude higher than bulk properties and increases with decreasing fiber radius. This is attributed to the oriented ionic morphology along the nanofiber. Furthermore, a nanofiber model was developed to extract the catalytic activity and gas diffusion coefficient of nanofiber. These characterization and modelling work can provide guidance to the design and optimization of catalyst layer with electrospun ionomer or composite nanofibers.

Electronic thermal transport measurement in low-dimensional materials with graphene non-local noise thermometry.

In low-dimensional systems, the combination of reduced dimensionality, strong interactions and topology has led to a growing number of many-body quantum phenomena. Thermal transport, which is sensitive to all energy-carrying degrees of freedom, provides a discriminating probe of emergent excitations in quantum materials and devices. However, thermal transport measurements in low dimensions are dominated by the phonon contribution of the lattice, requiring an experimental approach to isolate the electronic thermal conductance. Here we measured non-local voltage fluctuations in a multi-terminal device to reveal the electronic heat transported across a mesoscopic bridge made of low-dimensional materials. Using two-dimensional graphene as a noise thermometer, we measured the quantitative electronic thermal conductance of graphene and carbon nanotubes up to 70 K, achieving a precision of ~1% of the thermal conductance quantum at 5 K. Employing linear and nonlinear thermal transport, we observed signatures of energy transport mediated by long-range interactions in one-dimensional electron systems, in agreement with a theoretical model.

Synthesis, spectroscopic characterization, computational and biological evaluation of organometallic Re(I) complexes with 5-(2-butyl-5-chloro-1H-imidazol-4-yl)-1,3-diaryl- 4,5-dihydro-1H-pyrazole

Organometallic rhenium(I) complexes (I-VI) using substituted 5-(2-butyl-5-chloro-1H-imidazol-4-yl)-1,3-diaryl-4,5-dihydro-1H-pyrazole were synthesized and characterized by the spectroscopic method. For evaluation of HOMO-LUMO energy gap, estimation of bond angle, bond length data and Mulliken charge analysis DFT studies were performed. The interactions between synthesized compounds and HS-DNA were carried out by viscosity measurements and absorption titration gives information about modes of binding and the nucleolytic efficiency of compounds. Molecular docking study was performed to support the results of the viscosity measurements and absorption titration, Groove binding was suggested as the most possible mode and the DNA-binding (Kb) constants of the complexes were between 1.7 × 106 to 8.8 × 106 M−1. Thermodynamic parameter ΔG0 value ranging from −7227.0 to −9463.0 J/mole.K. According to the thermodynamic parameter, the main binding force could be judged. In vivo and in vitro cytotoxicity against the eukaryotic and prokaryotic cells gives the toxic nature of the synthesized compounds. An antimicrobial study was carried out by estimating MIC against two Gram-positive and three Gram-negative bacteria. the Electronic spectra and conductivity measurement confirm the different transition and non-electrolytic nature of the metal complexes.

In Situ Synthesis of Molybdenum Carbide Nanoparticles Incorporated into Laser‐Patterned Nitrogen‐Doped Carbon for Room Temperature VOC Sensing

AbstractCarbon laser‐patterning (CLaP) is emerging as a new tool for the precise and selective synthesis of functional carbon‐based materials for on‐chip applications. The aim of this work is to demonstrate the applicability of laser‐patterned nitrogen‐doped carbon (LP‐NC) for resistive gas‐sensing applications. Films of pre‐carbonized organic nanoparticles on polyethylenetherephthalate are carbonized with a CO2‐laser. Upon laser‐irradiation a compositional and morphological gradient in the films is generated with a carbon content of 92% near the top surface. The specific surface areas of the LP‐NC are increased by introducing sodium iodide (NaI) as a porogen. Electronic conductivity and surface area measurements corroborate the deeper penetration of the laser‐energy into the film in the presence of NaI. Furthermore, impregnation of LP‐NC with MoC1−x (<10 nm) nanoparticles is achieved by addition of ammonium heptamolybdate into the precursor film. The resulting doping‐sensitive nano‐grain boundaries between p‐type carbon and metallic MoC1−x lead to an improvement of the volatile organic compounds sensing response of ΔR/R0 = −3.7% or −0.8% for 1250 ppm acetone or 900 ppm toluene at room temperature, respectively, which is competitive with carbon‐based sensor materials. Further advances in sensitivity and in situ functionalization are expected to make CLaP a useful method for printing selective sensor arrays.

The effect of electrodeposition applied potential on the electrochemical performance of polyaniline films

Polyaniline (PANI) has been widely studied and used for the energy storage applications, especially in supercapacitors, this is due to their good pseudocapacitance properties, and it is easy for synthesis. In this study, we describe the effects of the electrodeposition applied potential on the electrochemical performance of polyaniline films. The electrodeposition of PANI films on fluorine-doped tin oxide (FTO) glass substrate is released by chronoamperometry technique using an electrolytic solution containing 0.3 M of aniline in 1 M H2SO4 at different applied potentials (i.e., + 0.8 V, + 0.9 V and + 1 V vs. SCE) for 300 sin time. All prepared films are characterized by different techniques scanning electronic microscopy, infrared spectroscopy, thermogravimetric analysis, and electrical conductivity measurement. For the application, the FTO/PANI films are used as material electrode in supercapacitor. The electrochemical performances are evaluated by cyclic voltammetry, galvanostatic charge–discharge tests, and electrochemical impedance spectroscopy. An important increase in specific capacitances is observed at 0.2 A g−1 from 54.8 F g−1 for FTO/PANI 0.8 film to 157.42 F g−1 for FTO/PANI 0.9 and 195.94 F g−1 for FTO/PANI 1.

Intrinsic electronic conductivity of individual atomically resolved amyloid crystals reveals micrometer-long hole hopping via tyrosines

Proteins are commonly known to transfer electrons over distances limited to a few nanometers. However, many biological processes require electron transport over far longer distances. For example, soil and sediment bacteria transport electrons, over hundreds of micrometers to even centimeters, via putative filamentous proteins rich in aromatic residues. However, measurements of true protein conductivity have been hampered by artifacts due to large contact resistances between proteins and electrodes. Using individual amyloid protein crystals with atomic-resolution structures as a model system, we perform contact-free measurements of intrinsic electronic conductivity using a four-electrode approach. We find hole transport through micrometer-long stacked tyrosines at physiologically relevant potentials. Notably, the transport rate through tyrosines (105 s-1) is comparable to cytochromes. Our studies therefore show that amyloid proteins can efficiently transport charges, under ordinary thermal conditions, without any need for redox-active metal cofactors, large driving force, or photosensitizers to generate a high oxidation state for charge injection. By measuring conductivity as a function of molecular length, voltage, and temperature, while eliminating the dominant contribution of contact resistances, we show that a multistep hopping mechanism (composed of multiple tunneling steps), not single-step tunneling, explains the measured conductivity. Combined experimental and computational studies reveal that proton-coupled electron transfer confers conductivity; both the energetics of the proton acceptor, a neighboring glutamine, and its proximity to tyrosine influence the hole transport rate through a proton rocking mechanism. Surprisingly, conductivity increases 200-fold upon cooling due to higher availability of the proton acceptor by increased hydrogen bonding.

Experimental measurement of proton conductivity and electronic conductivity of membrane electrode assembly for proton exchange membrane fuel cells

Charge transport processes involving the proton migration and electron transfer for different parts of membrane electrode assemble (MEA) play an essential role for developing the novel electrode and enhancing the electrochemical performance towards proton exchange membrane fuel cells (PEMFCs). However, the coupled charge transport processes make it difficult for evaluating proton conductivity and electronic conductivity of different parts in MEAs under operation conditions of fuel cells. Here in this work, we propose an experiment approach for separating the electronic conductivity and proton conductivity of different components of MEA at the operating conditions of PEMFCs. This approach involves two different measuring devices, which both consist of electron or proton conducting layers, sealing layers and sample layer, followed by tailoring the thickness of sample layers and via electrochemical impedance spectroscopy (EIS) to quantity the electronic conductivity and proton conductivity of different layers. These experiment results show the great potential in the development of different components of MEA.

Strengthening of multiferroicity in nickel titanate by modifying with bismuth and lead titanate

This article demonstrates that both ferroelectric and magneto-electric responses can be attained simultaneously in the ceramics of NiTiO3, Bi-modified NiTiO3, Bi- and PbTiO3 -modified NiTiO3 synthesized by the precursor solution method. The samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV–Vis) spectroscopy, electric field dependent polarisation (P-E hysteresis measurement), magneto-electric coefficient measurement, impedance spectroscopy, and electronic conductivity measurement techniques in different experimental conditions. The modifications of NiTiO3 with bismuth and then with lead titanate (PbTiO3) have provided a pure-phase perovskite structure with an excellent crystalline morphology, featuring a high relative permittivity and enhanced ferroelectricity and magneto-electric effect. It also exhibits that not only the magneto-electric effect is enhanced, but also the leakage current is reduced with the modifications.

Analysis of Important Fabrication Factors That Determine the Sensitivity of MWCNT/Epoxy Composite Strain Sensors.

Composite sensors based on carbon nanotubes have been leading to significant research providing interesting aspects for realizing cost-effective and sensitive piezoresistive strain sensors. Here, we report a wide range of piezoresistive performance investigations by modifying fabrication factors such as multi-wall carbon nanotubes (MWCNT) concentration and sensor dimensions for MWCNT/epoxy composites. The resistance change measurement analyzed the influence of the fabrication factors on the changes in the gauge factor. The dispersion quality of MWCNTs in the epoxy polymer matrix was investigated by scanning electron microscopy (SEM) images and conductivity measurement results. A configuration circuit was designed to use the composite sensor effectively. It has been shown that, in comparison with commercially available strain gauges, composites with CNT fillers have the potential to attain structural health monitoring capabilities by utilizing the variation of electrical conductivity and its relation to strain or damage within the composite. Based on the characteristics of the MWCNT, we predicted the range of conductivity that can be seen in the fabricated composite. The sensor may require a large surface area and a thin thickness as fabrication factors at minimum filler concentration capable of exhibiting a tunneling effect, in order to fabricate a sensor with high sensitivity. The proposed composite sensors will be suitable in various potential strain sensor applications, including structural health monitoring.

Synthesis and Characterization of LiFePO4 By Variation Addition Of (Li3PO4)0.5(AgI)0.25(LiI)0.25 as Cathode Material For All-Solid-State Li-ion Battery

The safety of lihium-ion batteries have always been a concerned for industrial application. Therefore, there is a strong interest to produce an all-solid-state battery. An all-solid-state battery has several advantages, including easy fabrication, non-flammable, low leakage, but mainly because it is safer. In this study, (Li3PO4)0.5(AgI)0.5(LiI)0.25 was synthesized as solid electrolyte. Meanwhile, as cathode, LiFePO4 was added by variations of: 0%, 10%, and 30% of (Li3PO4)0.5(AgI)0.5(LiI)0.25 to minimize the presence of solid state interface between solid electrolyte and cathode. The samples were characterized using Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and conductivity measurement. For SEM images, the particle distribution was not thoroughly homogeneous because it was prepared manually by only grinding the samples. The X-ray data showed that (Li3PO4)0.5(AgI)0.5(LiI)0.25 has halo pattern and the crystal structure of synthesized cathode belongs to P m n a space group (Olivine Structure). The range of measured AC conductivity was around 10−4 S/cm - 10−8 S/cm.