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The prime goal of this novel work is to investigate the efficacy of spinel zinc ferrite as a thermoelectric material and its performance enhancement for high temperature applications. Zn 1-x Ni x Fe 2 O 4 (0 ≤ x ≤ 0.2) were prepared by sol-gel method and their structural, morphological, and thermoelectric behaviours were examined as functions of composition and temperature. Among the studied compositions, Zn 0.8 Ni 0.2 Fe 2 O 4 exhibits the highest electrical conductivity (σ) of 49.83 S/m, the largest power factor of 6.66 μW/mK2, and the lowest thermal conductivity (κ) of 0.36 W/mK at 947 K, thus extending to an overall enhancement in the thermoelectric figure of merit (zT). Conduction through electron hopping is proven to be the main driving force for the enhancement in electrical and thus thermoelectric properties. Results reveal that thermoelectric properties of ZnFe 2 O 4 can potentially be enhanced by the doping Ni at Zn site and opens up an exciting opportunity for the utilization of this spinel ferrite as a novel thermoelectric material for applications involving elevated temperatures. [Display omitted] • Thermoelectric figure of merit of ZnFe 2 O 4 was considerably enhanced by doping Ni. • Electron hopping is found to be one of the major contributors for the enhancement of electrical conductivity. • The dopant is also effective in reducing the thermal conductivity of ZnFe 2 O 4 at higher temperatures. • The results indicate that the studied material is suitable for high temperature (>700K) thermoelectric applications. [ABSTRACT FROM AUTHOR]

This study investigates the effect of (Co + Al) co−doping on the physical properties of the ZnO nanoparticles, synthesized via the simple co−precipitation method. X−ray diffraction (XRD) analysis revealed a hexagonal structure for all samples, with a formation of Al 2 O 3 phase in both Zn 0.98 Co 0.01 Al 0.01 O and Zn 0.94 Co 0.01 Al 0.05 O nanoparticles. The crystallite size increased from 26.5 nm for ZnO to 16.6 nm for Zn 0.94 Co 0.01 Al 0.05 O nanoparticles. Scanning electron microscopy (SEM) technique showed a notable alteration in the morphology of ZnO upon the incorporation of Al. A transition from spherical nanoparticles in ZnO and Co doped ZnO to irregular, dendritic-like structures in (Co + Al) co−doped nanoparticles is observed. Transmission electron microscopy (TEM) substantiated the presence of the Al 2 O 3 phase in the co−doped samples. Raman and FTIR spectroscopy confirmed the incorporation of Co and Al into the ZnO lattice through the presence of Co–O–Co and Al–O bonds. Optical characterization indicated a decrease in the band gap energy from 3.18 eV in ZnO to 2.84 eV in Zn 0.94 Co 0.01 Al 0.05 O nanoparticles. Electrical conductivity measurements revealed an increase from 1.2 × 10−4 Ω−1 cm−1 to 1.8 × 10−3 Ω−1 cm−1 as the Al content increased from 0 % to 5 % at the frequency of 103 Hz and the temperature of 423K. Likewise, dielectric constant raised from 775 in ZnO to 5455 in Zn 0.94 Co 0.01 Al 0.05 O nanoparticles at the temperature 423K. These results highlight the potential of (Co + Al) co−doped ZnO nanoparticles for advanced optoelectronic applications. [ABSTRACT FROM AUTHOR]

Several strategies have been adopted to enhance the electrochemical features of metal-organic framework structures for water splitting, however, a suitable conditions can effectively boost the electrocatalytic activity. Herein, molybdenum-based zeolite imidazolate frameworks (Mo 2g ZIF-67 and Mo 4g ZIF-67) have been synthesized by solvothermal process and electrocatalytic activity was examined at various elevating temperatures of 1 M KOH electrolyte. Mo 4g ZIF-67 nanorods showed the overpotential (η 10) of 358 mV at 20 °C, which was improved to 221 mV at 80 °C for the oxygen evolution reaction. Mo 4g ZIF-67 nanorods exhibited the Tafel slope of 77 mV dec−1 at 80 °C and followed the Volmer-Heyrovsky mechanism. LSV curves reveal that Mo 4g ZIF-67 nanorods showed a greater current density and a good turnover frequency (TOF) of 221.0 ms−1 at the fixed V RHE of 0.7 V. Similarly, Mo 4g ZIF-67 nanorods revealed the η 10 of 181 and 93 mV at 20 and 80 °C, respectively for the HER process. Mo 4g ZIF-67 nanorods displayed a Tafel slope of 95 mV dec−1 and TOF of 213.50 ms−1. The enhanced electrocatalytic activity may be due to rising temperatures, enhanced electrical conductivity at rising temperatures, well defined nanorods shape and greater ECSA, which provided the active sites and facile the flow of charge carriers for oxygen and hydrogen evolution reaction. The electrocatalyst, Mo 4g ZIF-67 nanorods exhibited a uniform current density during stability tests for 30 h at 20 °C, which was increased at 80 °C. Temperature elevation remarkably enhanced the HER and OER characteristics of the Mo 4g ZIF-67 nanorods and suggested an effective electrocatalyst for water splitting. • Mo 4 gZIF-67 nanorods have been synthesized by solvothermal treatment. • Mo 4g ZIF-67 nanorods showed the η 10 of 221 mV at 80 °C for the OER process. • Mo 4g ZIF-67 nanorods exhibited a Tafel slope of 77 mV dec−1 at 80 °C for OER process. • Mo 4g ZIF-67 nanorods exposed the η 10 of 93 mV at 80 °C for the HER process. • Mo 4g ZIF-67 nanorods displayed a TOF of 213.50 ms−1. [ABSTRACT FROM AUTHOR]

In this study, the objective was to improve the performance of bismuth vanadium oxide Bi 4 V 2 O 11 by synthesizing double substituted compounds using copper ions Cu2+ and tantalum ions Ta5+. Bi 4 V 2-x Cu x/2 Ta x/2 O 11-3x/4 (0.1 ≤ x ≤ 0.5) polycrystalline samples of were prepared via the solid-state route. XRD patterns measured at room temperature revealed the stabilization of the monoclinic α-Bi 4 V 2 O 11 type structure for x = 0.1 and the tetragonal γ or γ' -Bi 4 V 2 O 11 for x > 0.2. This result has been confirmed by thermogravimetric analysis (DTA), FT-IR spectroscopy and Raman scattering measurements. The influence of the composition on the microstructure and grain size of the prepared samples was explored through dilatometric study, density measurements, and scanning electron microscopy (SEM). Thermal Raman spectra evolution was also investigated. The temperature-dependent Raman spectroscopy analysis of the compound α-BiCuTaVOx (x = 0.1) demonstrated variations in the position, intensity, and width of the Raman mode around 850 cm−1, indicating temperature-assisted structural modifications. One defining feature of the tetragonal-dominated phase of the BiMeVOx systems is the increasing merging of the weak band at 930 cm−1 with the dominating band at 850 cm−1. This behavior was also observed for our samples. The V–O bond lengths were calculated using an empirical relation based on the diatomic approximation. Electrochemical impedance spectroscopy (EIS) was used to investigate the changes in electrical conductivity with the substitution rate across the temperature range of 300–720 °C. The sample with x = 0.3 exhibited the highest electrical conductivity at both high and low temperatures. However, the optimal substitution rate to achieve the best conductivity in this series of copper and tantalum-substituted BiCuTaVOx was found to be x = 0.3 (σ = 4 × 10−3 S cm−1 at 600 °C). [ABSTRACT FROM AUTHOR]

In this work, we study the effect of Ni-doping on the structural and impedance spectroscopy properties of the polycrystalline YCrO 3 ceramic sample. The structural analysis shows all the samples crystallize in an orthorhombic structure with the Pnma space group. The depressed and asymmetric semicircle of complex impedance spectra indicates that the relaxation of charge carriers is of non-Debye type, where the thermally activated charge carriers control it. The temperature dependence of relaxation time and electrical conductivity exhibit an anomaly in the vicinity of diffuse-like relaxor transition temperature (T C ∼ 460 K). The analysis of conductivity data shows hopping-type charge conduction. The analysis further indicates that while the dc conductivity increases continuously, the activation energy shows a non-monotonous variation with Ni concentration. [ABSTRACT FROM AUTHOR]

This study aims to optimize the Pr 2 NiO 4+δ electrode material for increased phase stability at IT-SOFC operating temperatures while maintaining high electrochemical activity. This is achieved by double doping at both Pr and Ni sites. The series of new Pr 1.6 Ca 0.4 Ni 1–y Cu y O 4+δ complex oxides are synthesized by the pyrolysis of the glycerol-nitrate compositions. The resulting materials are extensively studied by room and high-temperature XRD, XPS, TGA, SEM, dilatometry, DC-four probe method, and impedance spectroscopy. The study has registered the formation of the homogeneous complex oxide phases with an orthorhombic structure (Bmab sp. gr.) throughout the dopant concentration range of y = 0.0–0.4. For the Cu-rich samples, an increased Pr4+ content and the presence of Ni2+ and Cu+1 are observed, resulting in a gradual decrease of both the electroconductivity and the absolute oxygen content (δ ∼ 0 at y ≥ 0.2). Nevertheless, the Pr 1.6 Ca 0.4 Ni 1–y Cu y O 4+δ series materials exhibit excellent phase stability and chemical and thermomechanical compatibility with CeO 2 - and BaCe(Zr)O 3 -based electrolytes. Moreover, Cu-doping enhances the electrochemical activity of the electrodes. The polarization resistance of the Pr 1.6 Ca 0.4 Ni 0.8 Cu 0.2 O 4+δ electrode, is in the range of 0.19–0.27 Ω cm2 (at 700 °C) depending on the electrolyte substrate and shows a low dependence on the water content, demonstrating the applicability of the electrode in fuel cells and electrolysis cells based on both oxygen-ion and proton-conducting electrolytes. [Display omitted] • New Pr 1.6 Ca 0.4 Ni 1–y Cu y O 4+δ (y ≤ 0.4) oxides are obtained by glycerol-nitrate pyrolysis. • These oxides exhibit increased phase stability and compatibility with electrolytes. • Double doping maintains satisfactory conductivity level. • Moderate Cu doping enhances electrochemical activity of the electrodes. • Pr 1.6 Ca 0.4 Ni 0.8 Cu 0.2 O 4+δ is a promising candidate for use in IT SOCs. [ABSTRACT FROM AUTHOR]

Pr 2 NiO 4+δ -based materials are considered as promising air electrodes for proton ceramic electrochemical cells due to their wide range of attractive properties. In the present work, the basic functional properties of Pr 2 NiO 4+δ are optimized by substituting Pr-cations with isovalent La- and Nd-ions. The synthesized samples are characterized by X-ray diffraction analysis, thermogravimetry in oxidizing and reducing environments, dilatometry, and four-probe conductivity measurements. As a result, the relationships between crystal and defect structures on the one hand and their electrotransport and thermomechanical properties on the other hand are revealed. The PrLaNiO 4+δ , Pr 1.5 La 0.5 NiO 4+δ , and PrLa 0.5 Nd 0.5 NiO 4+δ compositions are stabilized by the large lanthanum cation and do not show the phase transition (from Fmmm to I 4/ mmm space group) typical of the other studied compounds. The conductivity values of the studied materials remain practically unchanged for most of the compositions, but the La-doping reduces the activation energies of hole transfer. Based on the obtained data, two optimal compositions (Pr 1.5 La 0.5 NiO 4+δ and PrLa 0.5 Nd 0.5 NiO 4+δ) can be identified for their further application in electrochemical cells. [Display omitted] • (Pr x La y Nd z)PrNiO 4+δ (x + y + z = 1) are synthesized by citrate-nitrate method. • Doped materials obtained have orthorhombic structure of Pr 2 NiO 4+δ. • Doping with La or Nd results in a decrease of oxygen content of Pr 2 NiO 4+δ. • Nd- and La-doping have the opposite effect on thermal expansion of Pr 2 NiO 4+δ. • Doping with lanthanum reduces the activation energy of hole mobility. [ABSTRACT FROM AUTHOR]

Higher Manganese Silicides (HMS) are the best p-type materials beneficial for intermediate-temperature range thermoelectric device applications due to their high thermal stability and inexpensive constituent elements. Although the cost-effective HMS materials possess high thermal stability, they are concerned with high thermal conductivity values. The nanocomposite approach was promised to lower the thermal transport properties without affecting the electrical transport properties, which is experimented in the present work. The higher manganese silicide with varying weight percentages of nano-structured Si 0.8 Ge 0.2 B 0.02 inclusions was experimented to decrease the thermal conductivity and to enhance the electrical properties. The lowest thermal conductivity value of ≃ 2.24 W/mK was reported with 2 wt% Si 0.8 Ge 0.2 B 0.02 addition in HMS material. Also, the HMS-2 wt. % Si 0.8 Ge 0.2 B 0.02 improved the transport properties, electrical conductivity and Seebeck coefficient values of ≃ 4 × 104 S/m and ≃ 220 μV/K respectively. Furthermore, various mathematical models were proposed here to simulate the composite approach results, which were then correlated with experimental results. [ABSTRACT FROM AUTHOR]

Lanthanum nickel oxide (LaNiO 3, LNO) films exhibit excellent electrical conductivity but poor mechanical properties, considerably limiting their further development in the field of flexible electronics. In this study, flexible LNO thin films of different thicknesses were fabricated on a unique two-dimensional (2D) mica platform using a simple metal organic deposition technique. The obtained LNO films exhibited a pseudocubic phase without impurities. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterisations proved that the films were well-crystallised, dense, and flat, with controllable thickness. In addition, the flexible LNO/mica element possesses low resistivity (5 × 10−4 Ω cm), translucency, and good bending resistance. The electrical resistivity can remain stable under various bending radii (r = 10∼2 mm), thousands of bending cycles, and a wide temperature range (28–200 °C), demonstrating good durability, mechanical stability and temperature resistance. Furthermore, a ferroelectric BiFeO 3 film was constructed based on the obtained conductive LNO electrode, which exhibited typical ferroelectric characteristics. This excellent performance suggests that the flexible LNO electrode is promising for flexible electronic applications. [ABSTRACT FROM AUTHOR]

This study investigated the effect of TiO 2 content on the viscosity, free running temperature, electrical conductivity, crystallization behavior, and structure of high-titanium CaO–SiO 2 -10 wt% MgO-13 wt%Al 2 O 3 –TiO 2 -4 wt.% FeO slag by experiments and molecular dynamics simulations. The results revealed that increasing TiO 2 weakened the overall bonding energy and simplified the slag structure, leading to a decrease in viscosity and an increase in electrical conductivity. Thermodynamic calculations revealed a continuous enrichment of the slag towards the pseudobrookite region with increasing TiO 2 content. The precipitation of pseudobrookite phase during cooling resulted in short-slag characteristics and a rising free running temperature. Additionally, the peak intensity of pseudobrookite phase gradually enhanced and its morphology changed from elongated strips to plates with higher TiO 2 concentration. Structural analysis demonstrated that the poorly stabilized [TiO 6 ] octahedron was the major form of Ti atoms in the slag, and its proportion progressively increased with increasing TiO 2 content. [ABSTRACT FROM AUTHOR]

The synthesis of transparent thermoelectric materials, particularly at low processing temperature possesses a good promise for future power generation by renovating waste heat into electrical energy. The fabrication of invisible thermoelectric module is hindered by limited choices of appropriate p-type transparent thermoelectric materials so far. The present study deals with the growth and characterization of optically transparent p-type copper iodide (γ-CuI) thin films. Thermal annealing (maximum up to 200 °C) was performed to tune the electrical and optoelectronic properties for nurturing the thermoelectric performance. Annealing induced microstructural modifications instigated the preferential crystal growth by regulating the surface morphology. Low thermal conductivity is credited to strong phonon scattering leading to improved thermoelectric performance. Consequently, we attain a record Seebeck coefficient of ∼270 μV/K and power factor of ∼20 μW/(m·K2) that is almost two-order of magnitude higher as compared to conventional p-type transparent TE materials, indicating the potential of transparent γ-CuI thin films regarding its practical applicability in transparent thermoelectric devices. [ABSTRACT FROM AUTHOR]

Developing solid-state ionic conductors with desirable charge-transport efficiency and reasonable durability is a fundamental and long-lasting challenge for solid-oxide fuel cells (SOFCs). Ceria-based electrolytes, as one of the most common types of electrolytes for intermediate-temperature solid-oxide fuel cells (IT-SOFCs), offer a high surface-exchange coefficient and faster kinetics in the triple phase boundaries (TPBs); however, they suffer to some extent of electronic conductivity in the reducing atmosphere and gradual phase transitions. Here in this work, we have reported a novel co-doped IT-SOFC electrolyte composite combining the apatite structure of Lanthanum Silicate (LSO) with the fluorite structure of Gadolinium-doped Ceria (GDC), which showed a high ionic conductivity and a minimal electronic leak. The resulting GDC-LSO composite electrolyte also achieved an OCV (open-circuit voltage) of 1 V at 800 °C, implying a significant improvement in the OCV values reported for the typical ceria-based electrolytes (∼0.75 V). The sample was prepared using 40 wt% GDC and 60 wt% LSO (40GDC-60LSO) showed a maximum electrical conductivity of 25 mS cm−1 at 800 °C with good densification properties (>95 % relative density). The cell electrochemical performance measurement was conducted using a 3.0 vol% humified H 2 stream at the anode side while the cathode side was exposed to the air at 800 °C. The interdiffusion of cations between La3+ in the LSO phase and Ce4+ and Gd3+ in the GDC phase was detected by XRD and EDX results after sintering samples at 1500 °C for 4 h using 0.5 wt% PVA or 0.5 wt% Ethyl cellulose (EC) as the binder. The proposed GDC-LSO composite could help better understand the influence of compositional constituents and processing variables on the densification and electrical properties of the electrolyte materials for the IT-SOFCs. [ABSTRACT FROM AUTHOR]

Most oxidation studies involving interconnects are conducted in air under isothermal conditions, but during real-life solid oxide cell (SOC) operation, cells are also exposed a mixture of hydrogen and water vapor. For this study, an Fe–16Cr low-chromium ferritic stainless steel was coated with different reactive element oxides – Gd 2 O 3 , CeO 2 , Ce 0.9 Y 0.1 O 2 – using an array of methods: dip coating, electrodeposition and spray pyrolysis. The samples underwent oxidation experiments carried out over 100 h in three different atmospheres at 800 °C: air, an air/H 2 O mixture, and an Ar/H 2 /H 2 O mixture. The influence of different atmospheres on the corrosion of the Fe–16Cr steel was determined via oxidation kinetics studies; the corrosion product was evaluated using X-ray diffraction, scanning electron microscopy and area-specific resistance (ASR) measurements. All coated samples exhibited lower parabolic oxidation rate constants than bare steel and most also had lower ASR. The applied modifications were found to be sufficiently effective to allow the investigated low-chromium steel to be considered for application as an interconnect material for SOCs. [Display omitted] • Gd 2 O 3 -based thin layers improved corrosion resistance for all oxidation atmospheres. • Under some conditions RE perovskite phases were formed. • The thinnest scale was observed after oxidation in H 2 –H 2 O atmosphere. • Gd 2 O 3 -based thin layers significantly reduced ASR for all oxidation atmospheres. • Addition of Y to CeO 2 improves its electrical conductivity. [ABSTRACT FROM AUTHOR]

This study centers on the synthesis and characterization of a novel double perovskite, termed Sr 2 TiZrO 6 (STZO), which was synthesized using the conventional solid-state reaction method and subsequently calcined at 1000 °C for 12 h. X-ray diffraction (XRD) pattern refinement confirmed the formation of the tetragonal phase Sr 2 TiZrO 6 (space group P 4 mm), while both XRD and scanning electron microscope (SEM) analyses revealed that the resulting STZO displaying spherical-like grains with nanometric diameters. Thermogravimetric analysis revealed a minor weight loss attributed to the emergence of the ZrO 2 phase and the formation of the STZO double perovskite. The diffuse reflectance spectroscopy (DRS) results demonstrated strong UV-light absorption, with an optical absorption onset below 400 nm. The obtained band gap for direct transitions of the STZO sample is equal to 3.26 eV. The conductance and impedance study of the STZO sample are investigated. The present properties provide crucial insights to enhance comprehension of the STZO double perovskite material, which holds promise as a viable candidate for a range of applications, such as solar cells and photodiodes. [ABSTRACT FROM AUTHOR]

A series of Ba 0.75 Sr 0.25 Ti 1-x Zr x O 3 (x = 0, 0.01, 0.03, 0.05, and 0.1) ceramics were synthesized via a facile sol-gel route. The confirmation of a tetragonal structure was achieved through Rietveld refinement of the powder X-ray diffraction (XRD), and the finding was subsequently corroborated by Raman spectroscopy. The Scanning electron microscopy (SEM) confirmed the roughly cubical-shaped grains and average grain size is 0.31 μm for x = 0 and 0.70 μm for x = 0.05. The electrical properties such as dielectric constant, dielectric loss and ac/dc conductivity were investigated as a function of temperature and frequency. The Jonscher's universal power law (JPL) and Arrhenius equation have been used for the analysis of conductivity. The electrical conductivity variation at intermediate frequencies was explained using JPL. The Super-linear power law (SPL) explains the electrical response at higher frequencies. The temperature-dependent frequency exponents 's 1 ' and 's 2 ' were employed to predict the quantum mechanical tunneling (QMT), non-overlapping small polarons hopping (NSPT), and correlated barrier hopping (CBH) conduction mechanisms. [ABSTRACT FROM AUTHOR]

PrBaFe 2 O 6–δ (PBF) is considered as a promising material for mixed ionic-electronic conductors used in high-temperature applications. In the present work, PBF was used as a basis for two chemical modification approaches, including doping with cobalt, nickel and copper, as well as composite design with the addition of a BaCe 0.8 Sm 0.2 O 3–δ phase. The single-phase and composite materials were successfully prepared and characterized in terms of their functional properties. The two approaches were found to synergistically affect the functional properties of PBF, allowing a trade-off between thermomechanical and transport properties to be achieved. As a result, the prepared 70 wt% PrBaFe 1.9 M 0.1 O 6–δ (M = Co, Ni, Cu) + 30 wt% BaCe 0.8 Sm 0.2 O 3–δ composites exhibit acceptable electrochemical activity in the intermediate-temperature range. The best electrochemical activity was found for the sample with M = Cu, whose polarization resistance at 700 °C reaches 1.7 Ω cm2. Therefore, the designed PBF-based composites can be considered as promising electrode materials for solid oxide fuel cell applications. [Display omitted] • Homogeneous and heterogeneous doping strategies were used for PrBaFe 2 O 6–δ (PBF). • A partial substitution of iron-ions in PBF with nickel, cobalt or copper is made. • The Cu- and Ni-containing PBF samples exhibit better conductivity and reduced TECs. • Further modification of doped PBF is performed to create composite materials. • The as-prepared composites show acceptable polarization resistance values. [ABSTRACT FROM AUTHOR]

Highly conducting undoped ZnO ceramics were fabricated by flash sintering using commercial pure ZnO powder as a model system. The flash-sintered samples with diameters of 15 mm and heights of 2 mm exhibited relative densities ranging from 93.6% to 97.1% and room-temperature electrical conductivities between 205 and 590 S/cm. X-ray diffraction and Raman spectra indicated a high concentration of oxygen vacancies and zinc interstitials in the flash-sintered samples, increasing the carrier concentration. Detailed microstructural analyses show that clean grain boundaries and the morphology and distribution of impurities in flash-sintered samples are favorable for improving carrier mobility. Additionally, flash sintering has the advantage of reducing conditions, which reduces acceptor defects at ZnO grain boundaries, lowers Schottky barriers, and increases carrier mobility. The results show that flash sintering can synergistically enhance the carrier concentration and mobility in ZnO ceramics, making it a promising technique for fabricating highly conducting ZnO ceramics. [ABSTRACT FROM AUTHOR]

Ionic thermoelectric effect based on thermal migration of ion in the pore solution is emerging as a new branch of research on the thermoelectric effect of cement-based materials. However, the dense and tortuous pore structure of the cementitious materials may limit the ionic electrical conductivity and reduce the ionic thermal migration in pore solutions. Therefore, improving the pore structure may be a promising direction to enhance the thermoelectric effect of pore solution in cementitious materials. In this study, the pure cement paste with three water-cement ratios (w / c ratio = 0.3, 0.4, 0.5) and two curing methods (sealed curing and wet curing) are used. The effects of the ion concentration of the pore solution on the electrical conductivity and the Seebeck coefficient are investigated by the treatment of the vacuum saturation and the leaching process of the cement pastes. In addition, the pore structure of the cement paste is measured by mercury intrusion porosimetry (MIP). The effect of pore structure on the ionic thermoelectric effect of the cement pastes is studied. The results show not only the porosity and pore connectivity, but also the higher specific surface area of cement matrix is an important parameter for improving the ionic Seebeck coefficient of cementitious materials. The finer pore distribution in the cement matrix will cause a larger thermoelectric voltage. By improving the pore structure, the power factor (PF) of cement paste has been improved by two orders of magnitude, from 0.0027 μWm−1K−2 to 0.178 μWm−1K−2. The findings of this study can guide further understanding of the ionic thermoelectric effect of cementitious materials and provide a method for enhancing the thermoelectric effect of high-efficiency ionic thermoelectric materials (such as polyelectrolytes and ionic liquid) in cement matrix, which can develop ultra-high performance ionic thermoelectric cement-based materials for zero energy buildings. [ABSTRACT FROM AUTHOR]

In this research, Al/18Cu/3WC/3MoS 2 (wt.%) multilayered hybrid composites were fabricated by accumulative roll bonding (ARB), and their electrical and mechanical properties were investigated. After seven ARB cycles, an Al-matrix multilayered hybrid composite with a uniform distribution of WC-MoS 2 particles and Cu islands was achieved. The presence of the WC-MoS 2 particles and Cu islands significantly affected the electrical and mechanical properties of the fabricated composites. The composite obtained after seven ARB cycles showed an enhanced strength of 259 MPa. Also, it was found that the electrical conductivity of the Al matrix decreased by applied strain (about 19 % IACS) and the presence of the WC-MoS 2 particles. By annealing the fabricated composite obtained from final cycles, the electrical conductivity increased from 54 % IACS to 71 % IACS. [ABSTRACT FROM AUTHOR]

The concurrent enhancement of toughness, electrical conductivity, and thermal stability in polycrystalline diamond composites represents a formidable challenge. Here, a novel diamond-TiC composites (referred to as DTC) with high fracture toughness and conductivity were synthesized through a high-temperature and high-pressure reaction sintering process utilizing two precursors: diamond mixtures containing TiH 2 and Ti-coated diamonds. On the one hand, the inherent bonding and encasing of TiC onto the diamond matrix form a heterogeneous structure, providing high strength and excellent fracture toughness up to 11.6 MPa·m1/2. On the other hand, the established oxygen barrier and current pathway offer a thermal stability of 765 °C and high conductivity up to 837 S·m−1. Remarkably, this rare combination of mechanical, electrical, and thermal properties has been realized within a single material under relatively moderate sintering conditions, thus positioning diamond-TiC composites as a promising ceramic for electrical applications in high-stress environments. [ABSTRACT FROM AUTHOR]

In this study, layered perovskites were synthesized using a non-stoichiometric synthesis strategy that allowed the variation of the amount of Co substitution in the basic composition of SmBa 0.5 Sr 0.5 Co 2 O 5+d (SBSCO), used as a cathode material for Intermediate Temperature-operating Solid Oxide Fuel Cells (IT-SOFCs). SmBa 0.5 Sr 0.5 Co x O 5+d (x = 1.9–2.1, SBSCO-1.9–2.1), B-site non-stoichiometric layered perovskites, were analyzed to characterize the electrical and electrochemical properties with respect to the Co substitution. Among them, SmBa 0.5 Sr 0.5 Co 2.05 O 5+d (SBSCO-2.05) exhibited the best electrical and electrochemical properties with an ASR of 0.082 Ωcm2 and an electrical conductivity of 268.42 S/cm at 700 °C (measured in air within a series of measurements of increasing measuring temperature). Therefore, B-site non-stoichiometric perovskite compositions with increased Co substitution on their B sites represent a key strategy for achieving high performance cathodes compared to cathodes with stoichiometric compositions. • Layered perovskites with non-stoichiometric compositions achieved by variation of the Co amount at B-site were selected. • SmBa 0.5 Sr 0.5 Co 2.05 O 5+d shows the lowest ASR of 0.082 Ωcm2 at 700 °C. • SmBa 0.5 Sr 0.5 Co 2.05 O 5+d shows the highest electrical conductivity of 268.42 S/cm at 700 °C. • Non-stoichiometric compositions with increased Co substitution can enhance both electrochemical and electrical properties. [ABSTRACT FROM AUTHOR]

Planar heating elements employ carbon nanotubes, graphene, and metals. However, the high-temperature (300–500 °C) applications of heating elements based on metallic and organic materials are limited because they oxidize at high temperatures. Oxide materials such as RuO 2 are promising alternatives. The electrical conductivity of heating elements are strongly dependent on the aspect ratios of fillers; thus, RuO 2 nanosheets are suitable fillers for high-temperature planar heating elements because RuO 2 remains stable at high temperatures, and RuO 2 nanosheets have high aspect ratios of over 1000, as the lateral sizes and thicknesses of the RuO 2 nanosheets are 2∼5 μm and 1–3 nm, respectively. Consequently, the electrical conductivity of planar heating elements using RuO 2 nanosheets as fillers is 940 times higher than that of heating elements using conventional granular RuO 2 nanoparticles. Therefore, the RuO 2 nanosheet-based heating elements will be suitable in various applications requiring high temperatures and high uniformity. [ABSTRACT FROM AUTHOR]

Heat-assisted forming is gaining increasing attention for its potential in improving the formability and quality of metallic bipolar plate (BPP) of proton exchange membrane fuel cell (PEMFC). However, the effects of heat-assisted forming and the subsequent coating process on corrosion resistance and electrical conductivity of stainless steel BPP still remain unclear. This work proposes a way to improve simultaneously the corrosion resistance and electrical conductivity of heat-assisted forming stainless steel BPP by depositing a Cr–C coating directly on its surface without removing the oxide layer using the magnetron sputtering method. Potentiodynamic tests indicate that self-corrosion current density and corrosion current density at 1.0 V (vs. Ag/AgCl) of the Cr–C coated heat-assisted forming SS316L BPP prepared under 900 °C for 10 min are 0.021–0.040 μA cm−2 and 77.54 μA cm−2, respectively, both of which are smaller than those of coated SS316L BPP formed under room temperature. In addition, the contact resistance is close to that of the gold-plated copper plate under the same pressure. The corrosion resistant intermediate oxide layer and conductive network formed between Cr–C coating and metal substrate through defects of oxide layer may be the main reason for improvement of its corrosion resistance and electrical conductivity, respectively. [Display omitted] • A Cr–C coated heat-assisted forming bipolar plate with high performance is proposed. • Self-current densities of 0.022–0.056 μA cm−2 in fuel cell environment is obtained. • The retained intermediate oxide can contribute to a better corrosion resistance. • A lower electrical contact resistance approaching the gold coated copper is achieved. • The conductive network formed is beneficial for electrical conductivity improvement. [ABSTRACT FROM AUTHOR]

High electrical conductivity and low thermal conductivity are beneficial for the electrical discharge machining performance of ceramics. In this work, B 4 C–TiB 2 composites were prepared by spark plasma sintering of B 4 C–TiC–B powder mixture. The chemical reaction between TiC and B, together with subsequent selective matrix grain growth, expelled small in-situ generated TiB 2 grains to form conductive interlayers around large B 4 C grains. The unique microstructure significantly enhances the electrical conductivity of B 4 C–TiB 2 composites, especially at low TiB 2 content, while the ultrafine in-situ formed TiB 2 grains endow the composites with low thermal conductivity. The effects of TiB 2 content on the microstructure, mechanical properties, thermal & electrical conductivity of the composites were investigated. B 4 C–20 vol% TiB 2 composite exhibits excellent comprehensive performance, including a relative density, Vickers hardness, flexural strength, fracture toughness, room electrical and thermal conductivity of 98.6%, 28.15 GPa, 656 MPa, 5.46 MPa⋅m1/2, 1.08 × 105 S/m and 19.37 W/m⋅K, respectively. [ABSTRACT FROM AUTHOR]

Electrochemical co-deposition is a highly effective approach for achieving composites with specific composition and homogeneous distribution of reinforcement by manipulating electrolysis parameters. In this study, laminated carbon nanotubes reinforced copper composites (CNTs/Cu) were prepared through co-deposition and subsequent spark plasma sintering (SPS). In contrast to conventional powder metallurgy, the co-deposition method enables simultaneous deposition of CNTs and Cu particles while preserving the structural integrity of CNTs. It was observed that the CNTs were embedded within the growing Cu grains, resulting in a tightly bonded interface between them. The content of CNTs in composite deposited under current density of 0.5, 1.0 and 1.5 A⋅dm-2 is measured to be 0.51 vol%, 1.05 vol% and 1.31 vol%, respectively. The average grain size exhibited a significant reduction, decreasing from approximately 33.4 μm for pure Cu to 3.3 μm for the CNTs/Cu composite deposited under current density of 1.5 A⋅dm-2. Compared to pure Cu, the composite exhibited a significantly enhanced yield strength of 254 MPa, which is approximately 5 times that of pure Cu, the ultimate tensile strength improved to 290 MPa with an elongation of 15%, and the strengthening efficiency was calculated to be as high as 476. Load transfer is the primary contribution to the strength of the composites, followed by an increase in dislocation density and grain refinement. Meanwhile, the electrical conductivity of the composite with optimized condition demonstrated a high value of 94.4% IACS. The co-deposition method can facilitate the homogeneous dispersion of CNTs, enhance interfacial bonding, improve the structural integrity of CNTs, thereby enabling synergistic optimization of the properties of laminated CNTs/Cu composites. [ABSTRACT FROM AUTHOR]

The ceramic samples of Y 1-x Ca x Fe 0.5 Co 0 · 5 O 3 (x = 0.15, 0.25, 0.35) has been synthesized using solid-state reaction method. These samples exhibited orthorhombic perovskite structure and belonged to the Pbnm space group. X-ray analysis confirmed that Ca2+ ions replaced Y3+ ions at the A-site of perovskite structured YFe 0 · 5 Co 0 · 5 O 3 compound, while XPS studies confirmed the oxidation states of the constituent atoms. SEM micrographs and Williamson-Hall analysis showed that the crystallite size reduces with increasing Ca content, resulting in a strain-free, accommodated and stable microstructure. Complex impedance spectroscopic investigations established that the dispersion behaviors exhibited by the samples are due to Interfacial and Bulk polarizations. These phenomena are attributed to the accumulation of space charges and the hopping of electrons, respectively. Study further explore the semiconducting nature and negative temperature coefficient behavior of the material. Nyquist plots showed that grain interior is the major contributor to the conduction mechanism, while grain boundaries playing a secondary role. Correlated Barrier Hopping (CBH) has emerged as a suitable model to elucidate the conduction mechanism. The conduction process facilitated by CBH could potentially account for the observed negative permittivity in the material. [ABSTRACT FROM AUTHOR]

In the last decades, NiO-GDC and NiO-SDC composites have emerged as interesting anodic materials for low and intermediate-temperature Solid Oxide Fuel Cells (SOFC) due to their high electrical conductivities and low activation energies. In this work, we report a simple and efficient Solution Combustion Synthesis (SCS) procedure for fabricating NiO-GDC and NiO-SDC nanocomposites with attractive physical properties for applications in low-temperature SOFC. The nitrate-fuel combustion method using citric acid as organic fuel was chosen due to its relatively low cost and good efficiency. Their potential electrical and mechanical performance for competitive SOFC anode technologies was assessed by characterizing disk-like compacted powders obtained by SCS. Two structurally optimized NiO-GDC and NiO-SDC disks were considered for the study of these properties, which presented good porosity and compaction degree. Vickers hardness tests show the good mechanical properties of both samples, achieving maximum hardness values of 4.7–6.7 [GPa] and validating the efficiency of the used compaction process. Electrical conductivity studies suggest an insulating-like behavior for both samples, evidenced by an increase in conductivity as the temperature increases. Good conductivities and low activation energies about of 10−2 [S/cm] and 0.18 [eV] were estimated for a low-temperature operation regime (400–600 °C), respectively, representing a highly competitive performance concerning similar composites typically reported in the literature. Results show the efficiency of our fabrication procedures to produce efficient and competitive NiO-GDC and NiO-SDC composites with projections for future large-scale manufacturing of low-temperature SOFC anodes. [ABSTRACT FROM AUTHOR]

ZnO is one of the most promising mid-high temperature thermoelectric materials because of low cost, easy preparation and favorable chemical stability. Herein, the influence mechanism of Alkaline earth metal Ba doping on the thermoelectric properties of ZnO was studied. It is found that Ba doping can effectively improve the carrier mobility and electrical conductivity for that Ba doping can shorten the Zn–O bond and enhance the overlap and hybridization of electron orbitals. The electronic density of states of Zn and O is significantly enhanced. The highest power factor of ∼7.95 μWcm−1K−2 was obtained at 873 K, which is ∼1.4 times higher than that of the undoped sample. Due to the decrease of Young's modulus caused by Ba doping and the enhancement of phonon scattering of heavy element, the thermal conductivity decreases obviously in the whole temperature range. Ba doping enhanced the effect of phonon glass-electron crystal, and the ZT value of ∼0.345 was obtained at 873 K, which is ∼3.52 times as that of the pristine ZnO. The results indicated that alkaline earth metal doping is an effective way to improve the thermoelectric properties of ZnO functional materials. [ABSTRACT FROM AUTHOR]

Ternary B 4 C-SiC-ZrB 2 ceramics with eutectic compositions were prepared in situ by reactive spark plasma sintering at 1600–1800 °C. The two-step sintering, including an in situ reaction 2ZrSi 2 + 5B 4 C+ 3 C= 4B 4 C+ 4SiC+ 2ZrB 2 at 1600 °C and sintering at 1800 °C, is superior to combined one-step sintering at 1800 °C. The as-sintered 40B 4 C-40SiC-20ZrB 2 composites (sample 16R18) had grain sizes of microns with a density over 97%. The Vickers hardness, bending strength and fracture toughness of the ternary ceramic reached 28.6 GPa, 631 MPa and 5.50 MPa m1/2 respectively. Crack deflection and branching were ascribed to improved fracture toughness. The elongated plate-like ZrB 2 grains not only had toughening effects but also helped to lower the percolation threshold of the electrical conductivity. The 16R18 sample possessed an electrical conductivity of 5.38 × 104 S/m, owing to the tiny conductive ZrB 2 grains with aspect ratios of 3–4, which is beneficial for the electro-discharge machining of the B 4 C-SiC based composites. • The solid phase reaction at 1600 °C and densification at 1800 °C is advanced in obtaining B 4 C-SiC-ZrB 2 composites. • The two-step RSPS-ed B 4 C-SiC-ZrB 2 composite has grain sizes of 0.5–3 µm with an enhanced density of 97.6%. • The in situ elongated ZrB 2 grains are helpful to good comprehensive mechanical properties and electrical conductivity. [ABSTRACT FROM AUTHOR]

The issues related to microstructure and its effects on functional properties of electroceramics become increasingly prominent with the progressive downscaling of electronics. In this study, temperature-dependent dielectric and impedance data of BaTiO 3 (BT), Sr-doped BT (BST) and layer-structured BaBi 4 Ti 4 O 15 (BBTO) ceramics are systematically investigated to reveal the effects of doping and perovskite layering on the dielectric relaxation and conduction processes at high temperatures. By using complex impedance spectroscopy, it is demonstrated that the ceramics are electrically heterogeneous structures displaying a non-ideal Debye-like behavior at high temperatures. Using a suitable equivalent circuit model, the impedance diagrams at different temperatures are simulated and the refined values of macroscopic resistance and capacitance are used for the identification and characterization of particular microstructural regions (grains, grain boundaries, interfaces, etc.). The approach of combining the impedance, electric modulus and permittivity formalisms is demonstrated to be effective in explaining the peculiarities of the electrical charge transport mechanism and relaxation in the grains, grain boundaries and interface layers of the ceramics. • Electrical response of ferroelectric ceramics is described by the impedance, electric modulus and permittivity formalisms. • Band transport dominates long-range (non-localized) DC conduction in grains and grain boundaries. • Short-range transport occurs predominantly at interfaces through thermally activated hopping. • Sr-doping and perovskite layering reduce activation energies for the band conduction and dielectric relaxation. • Hopping mechanism is responsible for AC conductivity and low-frequency Maxwell-Wagner-type relaxation. [ABSTRACT FROM AUTHOR]

The perovskite ceramics La 1- x Gd x BaCo 2 O 5+ δ with double lanthanide at A site was synthesized by a traditional solid phase reaction method. The structure and properties of La 1- x Gd x BaCo 2 O 5+ δ were investigated by experiment and analysis. It can be seen from the X-ray diffraction (XRD) that the crystal structure changes from single perovskite to double perovskite with the increase of Gd3+ content. Refined by Rietveld method, it is found that with the increase of Gd, the crystal structure of La 1- x Gd x BaCo 2 O 5+ δ oxides changes from cubic phase for x = 0 to tetragonal phase for x = 0.5 and then to orthorhombic for x = 1.0. The La 1- x Gd x BaCo 2 O 5+ δ ceramics shows good toxicity resistance in CO 2 and good thermal compatibility with Ce 0.9 Gd 0.1 O 2- δ (GDC) at 1100 °C. Through the X-ray photoelectron spectroscopy (XPS) test, it is found that this series of ceramic materials have good oxygen catalytic reduction activity, and the electronic conductivity is better than LaBaCo 2 O 5+ δ (LBCO) and GdBaCo 2 O 5+ δ (GBCO). Combined with the thermal expansion test and the electrochemical AC impedance analysis, it is found that the thermal expansion coefficient (TEC) of La 0.5 Gd 0.5 BaCo 2 O 5+ δ (LG-55) is closer to that of GDC electrolyte than LBCO, and the specific area resistance is smaller than GBCO. All these findings indicate that it can be used as a potential cathode material for intermediate-temperature solid oxide fuel cell (IT-SOFC). • A-site double-lanthanide La 1- x Gd x BaCo 2 O 5+ δ was prepared to integrate the merits of LaBaCo 2 O 5+ δ (LBCO) and GdBaCo 2 O 5+ δ (GBCO). • The prepared perovskite materials La 1- x Gd x BaCo 2 O 5+ δ demonstrate high electrical conductivity. • La 1- x Gd x BaCo 2 O 5+ δ (x ≤ 0.5) samples showed good thermal compatibility with Gd 0.2 Ce 0.8 O 2- δ (GDC) electrolyte. • La 0.5 Gd 0.5 BaCo 2 O 5+ δ has relatively best corrosion resistance to CO 2. [ABSTRACT FROM AUTHOR]

The common assessment of soil salinity posits a linear function, which transfers the electrical conductivity (EC) of highly diluted extracts to the standard state of soil paste. Our study examines this assumption and explains its limitations in a wide range of EC for highly saline soils of the Aral region in Uzbekistan. For a comparative EC assessment in the liquid phase from standard soil pastes and 1:5 aqueous extracts we used portable EC–meters. The dependences of EC, total dissolved solids (TDS), and soil–water potential on the pore water content were evaluated using centrifugation to separate the liquid phase from the soil matrix. The non-linearity of the relationship between the EC of water from soil pastes and 1:5 water extracts for both average and median data over a broad (0.4–160 dS/m) range of their variation is detected. A strong retention and concentration of electrolytes in fine pores and water films resistant to vacuum extraction, as well as the nonlinear EC versus TDS relationship in highly saline soils are attributed to this nonlinearity. A comprehensive statistical analysis showed that despite the general non-linearity, in the EC range from 0 to 30–35 dS/m, the results for 1:5 extract can be reliably converted to the standard state using the dilution model for the liquid phase of the soil with one basic parameter of soil bulk density. For hypersaline soils (EC > 30–35 dS/m), conversion based on the dilution theory is unacceptable due to a strong underestimation of TDS. [ABSTRACT FROM AUTHOR]

Three borosilicate glass samples of 25 % Si 2 O – 30 % Na 2 O – 45 % B 2 O 3 doped with x Dy 2 O 3 (where x = 0, 2, and 4 mol %) were prepared using the melt quenching technique. Photoluminescence spectra for glass samples were studied when excited by 350 nm in the 400–800 nm range, where emission sharply increases for samples doped with 2 % Dy 2 O 3 (BSNDy2) at 580 nm after exposed to 30 kGy. Also, glass containing 2 % Dy photoluminescence constants, such as decay curves CIE chromaticity, was measured for all samples that gave three decay behaviors: slow, intermediate, and fast. Experimental lifetime (τ exp.), color coordination (X, Y), and yellow/blue intensity ratio (y/b) beside the color correlated temperature (CCT) were determined before and after being irradiated by 30 and 60 kGy from γ ray source where the y/b ratio of BSNDy2 increase by increasing exposure to gamma doses and were >1. In addition, electrical conductivity at different temperatures was investigated as the BSNDy2 sample gave the highest conductivity and decreased by BSNDy4. Moreover, shielding parameters such as the tenth value layer, half value layer, mean free path and mass attenuation coefficient values were calculated at different gamma-ray energies via the Phy-X program, showing the highest values for MAC, Z eff , N eff, and C eff for BSNDy4 sample. The findings showed that adding Dy 2 O 3 to the glass gave a fortified shielding character. [ABSTRACT FROM AUTHOR]

This manuscript proposes a method for effective discharging method of pulsed energy in industrial effluents. The proposed approach is based on the dielectric barrier discharge (DBD) and Electro hydraulic Plasma Discharge (EHPD). The objective function of the proposed approach is minimizing the concentration of the ethylene blue (MB) dye in the industrial waste water. Using DBD and EHPD technique, treating such industrial effluents before mixing to the running water can effectively prevent polluting the water bodies and human health. It is one of the tertiary waste water treatments, which can also degrade biological substances. DBD technique is one of the advanced oxidation technique to de-color MB dye and the EHPD reactor is a strong and extremely efficient method for the degradation of MB. By then, the proposed model is implemented in the MATLAB platform and the implementation is calculated with the present procedure. The study concludes that the DBD and EHPD method outperforms other methods in terms of degradation efficiency. De-colorization of methylene blue (MB) took just 15 s using a 3 KV, 50μs pulse. • Hybrid method using optimal power quality enhancement. • Honey Badger Algorithm (HBA). • Golden Jackal optimization (GJO). • Electro hydraulic Plasma Discharge (EHPD). [ABSTRACT FROM AUTHOR]

Electrical conductivity is one of the most important concerns in spinel-structured antioxidant films coated on a solid oxide fuel cell separator, and the mechanism of electrical conduction involves the small polaron hopping through corner-shared octahedral sites. Arranging favorable ions in the octahedral sites rather than in the tetrahedral sites is better for achieving higher electrical conduction. In this study, Zn, which prefers the tetrahedral site, was substituted for the Mn 1.5 Co 1.5 O 4 spinel to arrange site distribution. The crystal structure, electrical conductivity, and thermal expansion behavior of Zn-substituted ZMCOs [Zn x Mn 1.5−0.5x Co 1.5−0.5x O 4 (0.0 ≤ x ≤ 0.6)] were investigated. At Zn = 0.2, the highest electrical conductivity of 42.1 S/cm was observed, while at Zn > 0.2, the electrical conductivity decreased due to decreased Co2+/CoIII and Mn3+/Mn4+ pair concentration because Zn ions started to occupy the octahedral site. The higher the Zn concentration of ZMCO, the lower the distortion of the MnO 6 octahedron via the Jahn–Teller effect, resulting in a higher symmetry of the crystal structure. Therefore, with the increase in the Zn concentration, a mixture of tetragonal-cubic phase changed to cubic phase. In addition, the phase transition temperature of the tetragonal-cubic phase decreased. [ABSTRACT FROM AUTHOR]

The performance of proton exchange membrane fuel cells (PEMFCs) is influenced by the clamping force applied during assembly. However, the mechanisms are complex and many remain unveiled. This study addresses the effects of structural deformation and electrical contact resistance (ECR) caused by clamping force on the PEMFC performance. The individual and coupled effects of the structural deformation of the gas diffusion layer (GDL) and the ECR between the GDL and bipolar plate (BP) are discussed in detail, and positive and negative factors influencing the PEMFC performance and their competition relations are revealed. The optimal clamping force is determined by both the structural deformation and ECR. The optimal clamping force for PEMFC varies across different operating voltage ranges. The optimal clamping force is between 0.5 MPa and 1 MPa for low voltage range, and it is 2 MPa for medium voltage range, and the clamping force has minimal impact on PEMFC performance for high voltage range. The influence of clamping force remains consistent across various PEMFC operating temperatures and relative humidity levels. [Display omitted] • A fuel cell performance model under clamping force is developed. • Effects of structural deformation and contact resistance are investigated. • Mechanisms of fuel cell performance variations under the clamping force are revealed. • Optimal clamping forces for different fuel cell voltage ranges are determined. • The results can guide the design and assembly process of fuel cell. [ABSTRACT FROM AUTHOR]

Proton exchange membrane fuel cells (PEMFCs) with ultrahigh power density are highly required in recent years. In this work, breakthrough is achieved in electrical conductivity and anticorrosion capacity for the graphite-resin composite bipolar plates (BPs) under the limitation of greatly reduced thickness by high molding and high impregnation pressures (HH-BP). Interconnected laminar structure of expanded graphite (EG) is well preserved during the resin impregnation process. The power density (>1 W/cm2@ 2.75 A/cm2, 75 % RH) and limiting current density (∼3.25 A/cm2@ 0.3 V, 75 % RH) are much higher for fuel cells assembled with HH-BP compared to those under other different combinations of molding and impregnation pressures. The enhancement in power density is attributed to the decreased ohmic resistance induced by the ultrahigh electrical conductivity as confirmed in electrochemical impedance spectroscopy (EIS). Ultrathin composite BPs with high electrical conductivity provide an effective approach for enhancing the power density of PEMFCs. [Display omitted] • Graphite-resin composite bipolar plate (BP) was prepared by molding and impregnation process. • Ultrathin BP was obtained using high molding pressure and high impregnation pressure (HH-BP). • The electrical conductivities and anti-corrosion capacity were greatly enhanced for the HH-BP. • The power density and limiting current density were enhanced for fuel cell assembled with HH-BP. • Enhanced fuel cell electrochemical performance is due to high electrical conductivity of HH-BP. [ABSTRACT FROM AUTHOR]

The Fe/Mn-modified Mn–Co spinel oxides (MCO) are coated on SUS430 interconnect to protect against oxidation and chromium diffusion by wet spray followed by nitrate solution impregnation for intermediate-temperature solid oxide fuel cell (IT-SOFC) application. 1000 h oxidation tests at 800 °C show that the FeMCO-coated sample have the minimum parabolic rate constant (9.02 × 10−7 mg2cm−4s−1), which is lower than half of the uncoated sample. The area-specific resistance (ASR) of the FeMCO-coated sample is 6.41 mΩcm2 at 800 °C after 1000 h oxidation, which is much lower than the MCO sample (19.38 mΩ cm2) and the uncoated sample (186.84 mΩ cm2). The samples microstructures are examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Based on a novel approach, the dimensionless fluid numbers are related to the high-temperature conductivity of coated interconnects, and the inward diffusion of oxygen is introduced as the limiting factor for oxide-scale growth of coated interconnects. • Fe/Mn-modified Mn–Co-spinel coatings are formed via spraying and impregnation. • Coated samples are oxidized for 1000 h at 800 °C in air. • Fe-modified Mn–Co coating shows the lowest oxidation rate and ASR. • A fluid-flow based model is proposed to predict ASR with scale growth. [ABSTRACT FROM AUTHOR]

Presently, the formation of oxide films on the surface of Ti-based bipolar plates results in decreased electrical conductivity. This limitation frequently curtails the operational lifespan of proton exchange membrane fuel cells (PEMFCs). In this study, we engineered Ti alloy bipolar plate materials using an elemental screening process and validated their performance through experimentation. The elemental screening results identified eight elements, specifically Ni, Cr, Mo, Ta, W, Fe, Co, and Zn, as promising candidates for bipolar plate materials. Among these, Mo exhibited a pronounced affinity for incorporation into the TiO 2 oxide film. Conductivity measurements of passivated bipolar plates indicated that the Ti–Mo alloy displayed excellent electrical conductivity (1.699 × 1020 Ω m−1). Notably, the introduction of Mo (with an energy level of 1.64 eV) significantly reduced the band gap of the oxide film. Importantly, even after continuous potential oxidation for 10,000 s, the interfacial contact resistance (ICR) of Ti-0.35Mo (9.80 mΩ cm2) remained below the threshold set by the American DOE standard (ICR <10 mΩ cm2). Consequently, this research successfully devised a bipolar plate material utilizing a Ti–Mo alloy and proposed an innovative strategy for improving the conductivity of oxide films in bipolar plate materials via an elemental screening approach. [ABSTRACT FROM AUTHOR]

Soft ferrite nanoparticles with the composition Cd 0.4 Zn 0.6-x Co x Fe 1.9 Sm 0.1 O 4 , where x = 0.0, 0.2, 0.4, and 0.6, were effectively prepared using the green synthesis method. The cubic spinel structure of the produced soft ferrite was verified by X-ray diffraction investigation. For the various values of x, it was found that the average crystallite size and lattice constant varied between 34.50 nm and 27.28 nm and 8.5942 Å and 8.4479 Å, respectively. Images from scanning electron microscopy revealed the occurrence of aggregation and fine grain growth. An energy-dispersive X-ray spectroscopy investigation was employed to further confirm the ferrites composition. Tetrahedral absorption bands and metal ion-related absorption modes were found in Fourier-transform infrared spectra. As x changed from 0.0 to 0.6, the optical band gap energy (E g) showed a declining trend from 3.50 eV to 2.57 eV. Additionally, when the quantity of Co2+ increased, the DC electrical resistivity dropped from 5.0475 × 107 Ω cm to 4.3143 × 106 Ω cm. The dielectric characteristics, such as impedance, dielectric losses, and dielectric constant, showed a progressive decline with frequency. Notably, at high frequencies, the specimen Cd 0.4 Zn 0.2 Co 0.4 Fe 1.9 Sm 0.1 O 4 showed the greatest dielectric constant. The behavior of saturation magnetization was growing, and the estimated squareness values (S.Q., or Mr/Ms < 0.5) represent the ability of magneto-static interaction. Based on these characterization results, the synthesized soft ferrites are suitable for use in transformer cores, telecommunications equipment, and microwave devices. [ABSTRACT FROM AUTHOR]

Double perovskite materials are greatly appealing because of their multiferroic properties. Among such materials, double perovskite with rare earth metals are widely studied by researchers. Presently, the double perovskite La 2 NiMnO 6 (LNMO) samples are synthesized using the hydrothermal method by varying the concentration of the solvent (NaOH). The Powder X-ray diffraction analysis confirmed the formation of monoclinic structure with the P2 1 /n space group for prepared LNMO samples. The SEM image of the prepared samples revealed a cube-like structure. The impedance, dielectric, AC conductivity and modulus are studied in a wide frequency range from 100 Hz to 5 MHz to analyse the electrical and microstructure properties of the synthesized LNMO samples. The presence of a non- Debye type of relaxation peak is confirmed by impedance, dielectric and modulus studies. The effect of grains and grain boundaries are analysed by the Nyquist plot and the polarization of the materials are explained by the Maxwell-Wagner interfacial polarization model and Koop's theory. Using a three electrode system, the electrochemical behaviour of prepared LNMO samples are studied in various concentration of electrolyte (KOH) at different scan rates and found to have a pseudocapacitive nature. The highest specific capacitance value for LNMO10 is 44.60 F/g, LNMO20 is 50.14 F/g and LNMO30 is 25.81 F/g at a scan rate of 10 mV/s for 3 M KOH. The room temperature magnetic behaviour of synthesized LNMO samples analysed by Vibrating Sample Magnetometer paves way for magnetic storage applications. [ABSTRACT FROM AUTHOR]

In the buffalo dairy sector, a huge effort is still needed to improve mastitis prevention, detection, and management. Electrical conductivity (EC) and total somatic cell count (SCC) are well-known indirect indicators of mastitis. Differential somatic cell count (DSCC), which represents the proportion of neutrophils and lymphocytes on the total SCC, is instead a novel phenotype collected in the dairy cattle sector in the last lustrum. As little is known about this novel trait in dairy buffalo, in the present study we explored the nongenetic factors affecting DSCC, as well as EC and total somatic cell score (SCS), in the Italian Mediterranean buffalo. The data set used for the analysis included 14,571 test-day (TD) records of 1,501 animals from 6 herds, and climatic information of the sampling locations. The original data were filtered to exclude animals with less than 3 TD per lactation and, for the investigated traits, outliers beyond 4 standard deviations. In the statistical model we included the fixed effects of herd (6 classes), days in milk (DIM; 10 classes of 30 d, with the last being an open class until 360 d), parity (6 classes, from 1 to 6+), year-season of calving (11 classes, from summer 2019 to winter 2021/2022), year-season of sampling (9 classes, from spring 2020 to spring 2022), production level (4 classes based on quartiles of average milk yield by herd), and temperature-humidity index (THI; 4 classes based on quartiles, calculated using the average temperature and relative humidity of the 5 d before sampling). Average EC, SCS, and DSCC vary across herds. Considering DIM, greater EC values were observed at the beginning and the end of lactation; SCS was slightly lower, but DSCC was greater around the lactation peak. Increased EC, SCS, and DSCC levels with increasing parity were reported. Year-season calving and year-season sampling only slightly affected the variation of the investigated traits. Milk of high-producing buffaloes was characterized by lower EC and SCS mean values, nevertheless it had slightly greater DSCC percentages. Buffaloes grouped in the highest THI classes (classes 3 and 4) showed, on average, greater EC, SCS, and DSCC in comparison to the lower classes, especially to class 2. Results of the present study represent a preliminary as well as necessary step for the possible future inclusion of EC, SCS, or DSCC in breeding programs aimed to improve mastitis resistance in dairy buffaloes. [ABSTRACT FROM AUTHOR]

Material Extrusion (MEX) Additive Manufacturing of metal components is increasingly applied in recent years due to its low cost and potential for multi-material printing, with filament-based MEX being widely developed among all subdivisions of MEX. This technology utilises a compounded filament of polymeric binders and metal powder. The printing process involves hot extrusion of the compounded filament, which acts as a carrier of the metal powder and is deposited along a programmed print path to construct a 3D part. The as-printed parts are debound in several steps to ensure complete binder removal and pressureless sintered, targeting high densification levels. In this work, a copper-based filament was utilised as feedstock material and a full factorial design of experiments was performed to study the effect of layer height, volumetric speed and flowrate multiplier on the density of the as-printed part. Selected specimens from the DoE were debound and sintered and characterised. Various tests including density measurements, SEM, optical microscopy, micro-CT, etc., were applied at different stages to evaluate the porosity in the filament and printed parts. As a result, a relative density of 94% and an electrical conductivity of 63 %IACS (international annealed copper standard) were achieved for the sintered copper, which could be directly linked to the purity of the feedstock material. [ABSTRACT FROM AUTHOR]

This study investigates the influence of the sintering temperature on the properties of the screen-printed anode of the La 0.6 Sr 1.4 MnO 4 (LSMO 4) Ruddlesden‒Popper (R–P) perovskite for intermediate-temperature solid oxide fuel cell applications. LSMO 4 precursor powders with a K 2 NiF 4 -type (I4/mmm space group) tetragonal structure, density of 5.823 g/cm3, and specific surface area of 2.121 m2/g were successfully synthesised through the citrate-nitrate method. Initially, the characterisation of LSMO 4 anode powders was analyzed by X-ray diffraction, field emission scanning electron microscopy (FESEM), and Brunauer-Emmett-Teller analysis. Subsequently, an LSMO 4 film was screen-printed onto LSGM substrates and sintered at four different temperatures: 1000 °C, 1100 °C, 1200 °C, and 1300 °C. The effect of the sintering temperature on the microstructure, electronic conductivity, and electrochemical performance of the screen-printed anode film was analyzed by FESEM, DC 4-point probe method, and electrochemical impedance spectroscopy (EIS). The different values of average surface porosities (21–35%) and anode film thickness (14–41 μm) resulting from various sintering temperatures significantly influenced the electronic conductivity and electrochemical performance of the anode films. The electrical conductivities of the anode films sintered at 1000 °C, 1100 °C, 1200 °C, and 1300 °C were found to be 1.53 S/cm, 1.95 S/cm, 3.30 S/cm, and 3.73 S/cm at 800 °C, respectively. The activation energy of anodes sintered at 1000–1300 °C was in the range of 0.61–0.72 eV. The EIS analysis showed that the LSMO 4 anode film sintered at 1000 °C possessed the lowest ASR of 1.52 Ωcm2 at 800 °C under a wet gas mixture environment, 3 vol% H 2 O – 97 vol% (H 2 : N 2 = 10 : 90). The findings of this study provide valuable insights into the design and optimization of R–P perovskite based anode materials. [Display omitted] • L 0.6 Sr 1.4 MnO 4 (LSMO 4) is a potential Ruddlesden‒popper (RP) perovskite for IT-SOFC. • Sintering temperature influenced the properties of screen-printed LSMO 4 anode films. • LSMO 4 sintered at 1300 °C showed the highest conductivity of 3.73 S/cm at 800 °C. • Activation energy of LSMO 4 sintered at 1000–1300 °C was in the range of 0.61–0.72 eV. • LSMO 4 sintered at 1000 °C showed the lowest ASR at 800 °C in this work. [ABSTRACT FROM AUTHOR]

Due to its excellent electrical conductivity and stable Magnéli phase structures, cermet Ti 4 O 7 has emerged as one of the most promising materials in the fields of electrochemical application. However, the difficulties in creating high specific surface area structures, having room for conductivity enhancement when used as a conductive additive, and passivation forming TiO 2 under sufficiently oxidizing conditions limit the development of Ti 4 O 7 for practical applications. In this work, the V-doped Ti 4 O 7 hollow spheres with improved electrical conductivity and thermal stability were synthesized by the three-step approach of solvothermal reaction, oxidative crystallization, and hydrogen reduction without any surfactant or template. The formation mechanism of hollow (Ti,V) 4 O 7 was revealed by analyzing the valence evolution of V and comparing the morphology of Ti 4 O 7. The conductivity of Ti 4 O 7 and (Ti,V) 4 O 7 was compared and contrasted as functions of pressure, demonstrating the superiority of (Ti,V) 4 O 7 in terms of conductivity. Thermograms showed that the addition of V increased the complete oxidation temperature of Ti 4 O 7. Moreover, the reason for the enhanced electrical conductivity and thermal stability of V-doped Ti 4 O 7 was also revealed based on density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

This research is focused on designing new ceramic oxides with the spinel structure for a potential application as sensitive temperature and magnetic field sensors. In this respect, the mixtures of ferrimagnetic NiFe 2 O 4 with low-resistive Ni 0.66 Cu 0.41 Mn 1.93 O 4 semiconductor (molar coefficient α = 1 / 5 and 1 / 2) were prepared using the chemical co-precipitation technique followed by a low-temperature sintering of the cold-pressed powders. For the prepared materials, a variation of the electrical conductivity σ dc with temperature T (in the range 50 K–400 K) is quantitatively analyzed using different theoretical concepts of the charge carrier hopping transport occurring in disordered materials with strong electron-phonon interaction. It has been shown that an increase in α from 0 to 1 / 2 causes a step-like change of the dc electrical conductivity and, simultaneously, a gradual change in the magnetization M determined in the saturation state. The temperature coefficient of resistance T C R of the prepared ceramics takes the values from −0.6%/K (at 400 K) to −19.6%/K (below 100 K). The highest absolute value of the magneto-resistance coefficient M R determined at 150 K (and at magnetic field 7 T) registered for ceramic oxide with α = 1 / 2 was found to be 3.4%. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) based alloys are the most promising hydrogen storage and fuel cell alloys due to their high hydrogen content. In the present work, multilayer thin films (Mg/Ti/Ni) were prepared using direct current (DC) magnetron sputtering method. Multilayered Mg/Ti/Ni thin films were investigated by analyzing the data of different characterizations such as surface, structural, optical and electrical. Uniformity of the deposited thin films was analyzed by Field Emission Scanning Electron Microscope (FE-SEM) and Energy Dispersive Spectrometry (EDS) confirmed the presence of elemental composition. X-ray Diffractometer (XRD) was used to analyze structural characteristics of annealed thin films before and after hydrogenation. The variation in optical absorption and band gap has been observed, with the hydrogenation of thin film and having a larger band gap (3.27 eV) as compared to annealed thin films (2.81 eV). The semiconducting behavior of films is revealed by current voltage (I–V) characteristics of the films, and conductivity reduces after annealing and hydrogenation i.e. from 6.36 to 1.41 kΩ−1cm−1. Furthermore, Hall mobility of annealed without hydrogenated and annealed with hydrogenated thin film was improved (in the order of 103) as compared with as-deposited film. Improvement certainly helps the movement of hydrogen particularly after hydrogenation, the accumulation of hydrogen, particularly at the thin film's interface, obstructs the flow of electrons, resulting in a decrease in thin film conductivity. As a result, multilayer Mg/Ti/NI thin films are the good choice in the consideration for solid state hydrogen storage purpose. [Display omitted] • Investigations of direct current (DC) magnetron sputtered Mg/Ti/Ni multilayer. • Hydrogenation impact on the conductivity and energy bandgap of Mg/Ti/Ni multilayer. • XRD and SEM-EDS study for uniformly deposition and elemental composition of thin film. • Hall Effect measurements to elaborate the n-type conduction of prepared Mg/Ti/Ni multilayer. [ABSTRACT FROM AUTHOR]