Showing papers on "Conductivity published in 2012"
TL;DR: In this paper, the authors proposed a simple yet robust film treatment method with methanol having only one hydroxyl group to enhance the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) by four orders of magnitude.
Abstract: We proposed a simple yet robust film treatment method with methanol having only one hydroxyl group to enhance the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) by four orders of magnitude. Different methods of film treatment: immersing PEDOT:PSS film in the methanol solution; dropping methanol on the film; and a combination of these are employed and the results are compared. The conductivity of PEDOT:PSS films was enhanced from 0.3 S cm−1 to 1362 S cm−1 after film treatment with methanol. Other alcohols like ethanol and propanol were also used to treat the PEDOT:PSS film and showed inferior conductivity enhancement compared to methanol. The conductivity enhancement was greatly affected by the hydrophilicity and dielectric constant of the alcohols used. The mechanism of conductivity enhancement was investigated through various characterization techniques including FTIR, XPS and AFM. Removal of the insulator PSS from the film, and morphology and conformational changes are the mechanisms for the conductivity enhancement. The treated films also showed high transmittance and low sheet resistance desirable for a standalone electrode. ITO-free polymer solar cells were fabricated using PEDOT:PSS electrodes treated with methanol and showed almost equal performance to ITO electrodes.
697 citations
TL;DR: In this paper, the authors present low temperature electrical transport experiments in five field effect transistor devices consisting of monolayer, bilayer and trilayer MoS2 films, mechanically exfoliated onto Si/SiO2 substrate.
Abstract: We present low temperature electrical transport experiments in five field effect transistor devices consisting of monolayer, bilayer and trilayer MoS2 films, mechanically exfoliated onto Si/SiO2 substrate. Our experiments reveal that the electronic states in all films are localized well up to the room temperature over the experimentally accessible range of gate voltage. This manifests in two dimensional (2D) variable range hopping (VRH) at high temperatures, while below \sim 30 K the conductivity displays oscillatory structures in gate voltage arising from resonant tunneling at the localized sites. From the correlation energy (T0) of VRH and gate voltage dependence of conductivity, we suggest that Coulomb potential from trapped charges in the substrate are the dominant source of disorder in MoS2 field effect devices, which leads to carrier localization as well.
638 citations
TL;DR: In this paper, Li7−xLa3Zr2−xTaxO12 (0 ≤ x ≤ 1) was prepared by conventional solid-state reaction and the phase formation and the lithium-ion conductivity were determined using X-ray diffraction (XRD), neutron diffraction and AC impedance.
Abstract: The garnet-related oxides with the general formula Li7−xLa3Zr2−xTaxO12 (0 ≤ x ≤ 1) were prepared by conventional solid-state reaction. X-ray diffraction (XRD), neutron diffraction and AC impedance were used to determine phase formation and the lithium-ion conductivity. The lattice parameter of Li7−xLa3Zr2−xTaxO12 decreased linearly with increasing x. Optimum Li-ion conductivity in the Li-ion garnets Li7−xLa3Zr2−xTaxO12 is found in the range 0.4 ≤ x ≤ 0.6 for samples fired at 1140 °C in an alumina crucible. A room-temperature σLi ≈ 1.0 × 10−3 S cm−1 for x = 0.6 with an activation energy of 0.35 eV in the temperature range of 298–430 K makes this Li-ion solid electrolyte attractive for a new family of Li-ion rechargeable batteries.
511 citations
TL;DR: A novel class of solid electrolytes with three-dimensional conducting pathways based on lithium-rich anti-perovskites (LiRAP) with ionic conductivity of σ > 10(-3) S/cm at room temperature and activation energy of 0.2-0.3 eV is presented.
Abstract: Lithium ion batteries have shown great promise in electrical energy storage with enhanced energy density, power capacity, charge–discharge rates, and cycling lifetimes. However common fluid electrolytes consisting of lithium salts dissolved in solvents are toxic, corrosive, or flammable. Solid electrolytes with superionic conductivity can avoid those shortcomings and work with a metallic lithium anode, thereby allowing much higher energy densities. Here we present a novel class of solid electrolytes with three-dimensional conducting pathways based on lithium-rich anti-perovskites (LiRAP) with ionic conductivity of σ > 10–3 S/cm at room temperature and activation energy of 0.2–0.3 eV. As temperature approaches the melting point, the ionic conductivity of the anti-perovskites increases to advanced superionic conductivity of σ > 10–2 S/cm and beyond. The new crystalline materials can be readily manipulated via chemical, electronic, and structural means to boost ionic transport and serve as high-performance s...
420 citations
TL;DR: In this article, the authors investigate the variation of thermal conductivity of hybrid graphene nanostructures: stripe superlattices and BN (graphene) dots embedded in graphene (BN) using equilibrium molecular dynamics.
Abstract: Chemical and structural diversity present in hexagonal boron nitride ($h$-BN) and graphene hybrid nanostructures provide avenues for tuning various properties for their technological applications. In this paper we investigate the variation of thermal conductivity ($\ensuremath{\kappa}$) of hybrid graphene/$h$-BN nanostructures: stripe superlattices and BN (graphene) dots embedded in graphene (BN) are investigated using equilibrium molecular dynamics. To simulate these systems, we have parametrized a Tersoff type interaction potential to reproduce the ab initio energetics of the B-C and N-C bonds for studying the various interfaces that emerge in these hybrid nanostructures. We demonstrate that both the details of the interface, including energetic stability and shape, as well as the spacing of the interfaces in the material, exert strong control on the thermal conductivity of these systems. For stripe superlattices, we find that zigzag configured interfaces produce a higher $\ensuremath{\kappa}$ in the direction parallel to the interface than the armchair configuration, while the perpendicular conductivity is less prone to the details of the interface and is limited by the $\ensuremath{\kappa}$ of $h$-BN. Additionally, the embedded dot structures, having mixed zigzag and armchair interfaces, affect the thermal transport properties more strongly than superlattices. The largest reduction in thermal conductivity is observed at 50$%$ dot concentration, but the dot radius appears to have little effect on the magnitude of reduction around this concentration.
398 citations
TL;DR: Although HKUST-1 is neutral, coordinated water molecules are rendered sufficiently acidic by Cu(II) to contribute protons to pore-filling methanol molecules and thereby enhance the alternating-current conductivity, and substantial proton conductivity with the "as synthesized" version of this material is observed.
Abstract: HKUST-1, a metal–organic framework (MOF) material containing CuII-paddlewheel-type nodes and 1,3,5-benzenetricarboxylate struts, features accessible CuII sites to which solvent or other desired molecules can be intentionally coordinated As part of a broader investigation of ionic conductivity in MOFs, we unexpectedly observed substantial proton conductivity with the “as synthesized” version of this material following sorption of methanol Although HKUST-1 is neutral, coordinated water molecules are rendered sufficiently acidic by CuII to contribute protons to pore-filling methanol molecules and thereby enhance the alternating-current conductivity At ambient temperature, the chemical identities of the node-coordinated and pore-filling molecules can be independently varied, thus enabling the proton conductivity to be reversibly modulated The proton conductivity of HKUST-1 was observed to increase by ∼75-fold, for example, when node-coordinated acetonitrile molecules were replaced by water molecules In c
358 citations
TL;DR: In this paper, the bulk electrical conductivity of most topological insulators is relatively high, masking many of the important characteristics of its protected, surface conducting states, and counter-doping reduces the bulk conductivities of Bi2Se3 significantly, allowing these surface states and their properties to be clearly identified.
Abstract: Despite their name, the bulk electrical conductivity of most topological insulators is relatively high, masking many of the important characteristics of its protected, surface conducting states. Counter-doping reduces the bulk conductivity of Bi2Se3 significantly, allowing these surface states and their properties to be clearly identified.
347 citations
TL;DR: In this paper, a self-assembly in latex and static hot pressing is used to produce a composite with a percolation threshold of ∼ 0.62 vol% and a conductivity of 0.03 S m−1 at a content of 1.78 vol%, which is ∼5 orders of magnitude higher than that of the composites made by conventional methods at the same loading fraction.
Abstract: Vulcanized graphene/natural rubber composites with a conductive segregated network exhibiting good electrical conductivity, water vapor permeability and high mechanical strength are prepared by self-assembly in latex and static hot pressing. The composite exhibits a percolation threshold of ∼0.62 vol% and a conductivity of 0.03 S m−1 at a content of 1.78 vol%, which is ∼5 orders of magnitude higher than that of the composites made by conventional methods at the same loading fraction.
264 citations
TL;DR: It is shown that nanotubes can be packaged within insulating clay layers to form effective 3D nanofillers that increase the lithium ion conductivity of PEO electrolyte by almost 2 orders of magnitude.
Abstract: There is a growing shift from liquid electrolytes toward solid polymer electrolytes, in energy storage devices, due to the many advantages of the latter such as enhanced safety, flexibility, and manufacturability. The main issue with polymer electrolytes is their lower ionic conductivity compared to that of liquid electrolytes. Nanoscale fillers such as silica and alumina nanoparticles are known to enhance the ionic conductivity of polymer electrolytes. Although carbon nanotubes have been used as fillers for polymers in various applications, they have not yet been used in polymer electrolytes as they are conductive and can pose the risk of electrical shorting. In this study, we show that nanotubes can be packaged within insulating clay layers to form effective 3D nanofillers. We show that such hybrid nanofillers increase the lithium ion conductivity of PEO electrolyte by almost 2 orders of magnitude. Furthermore, significant improvement in mechanical properties were observed where only 5 wt % addition of the filler led to 160% increase in the tensile strength of the polymer. This new approach of embedding conducting-insulating hybrid nanofillers could lead to the development of a new generation of polymer nanocomposite electrolytes with high ion conductivity and improved mechanical properties.
258 citations
TL;DR: In this paper, a facile and environmentally friendly approach to prepare well-dispersed graphene sheets by γ-ray induced reduction of a graphene oxide (GO) suspension in N,N-dimethyl formamide (DMF) at room temperature is demonstrated.
Abstract: We demonstrate a facile and environmentally friendly approach to prepare well-dispersed graphene sheets by γ-ray induced reduction of a graphene oxide (GO) suspension in N,N-dimethyl formamide (DMF) at room temperature. GO is reduced by the electrons generated from the radiolysis of DMF under γ-ray irradiation. The reduced GO by γ-ray irradiation (G-RGO) can be re-dispersed in many organic solvents, and the resulting suspensions are stable for two weeks due to the stabilization of N(CH3)2+ groups on G-RGO. Additionally, G-RGO is efficient in improving the conductivity of polystyrene (PS). Its PS nanocomposites exhibit a sharp transition from electrically insulating to conducting with a low percolation threshold of 0.24 vol% and a high electrical conductivity of 45 S m−1 is obtained with only 2.3 vol% of G-RGO. The superior electrical conductivity is attributed to the uniform dispersion of the G-RGO sheets in the PS matrix.
233 citations
TL;DR: A group IVA based nanotube heterostructure array, consisting of a high-capacity Si inner layer and a highly conductive Ge outer layer, to yield both favorable mechanics and kinetics in battery applications.
Abstract: Problems related to tremendous volume changes associated with cycling and the low electron conductivity and ion diffusivity of Si represent major obstacles to its use in high-capacity anodes for lithium ion batteries. We have developed a group IVA based nanotube heterostructure array, consisting of a high-capacity Si inner layer and a highly conductive Ge outer layer, to yield both favorable mechanics and kinetics in battery applications. This type of Si/Ge double-layered nanotube array electrode exhibits improved electrochemical performances over the analogous homogeneous Si system, including stable capacity retention (85% after 50 cycles) and doubled capacity at a 3C rate. These results stem from reduced maximum hoop strain in the nanotubes, supported by theoretical mechanics modeling, and lowered activation energy barrier for Li diffusion. This electrode technology creates opportunities in the development of group IVA nanotube heterostructures for next generation lithium ion batteries.
TL;DR: In this article, the phase formation of cubic tantalum substituted LLZTO ceramics was studied by X-ray powder diffraction, where Ta substitution was found to facilitate the formation of the cubic garnet modification at lower synthesis temperature.
TL;DR: An ionic coordination network consisting of protonated imidazole and anionic one-dimensional chains of Zn(2+) phosphate was synthesized and possesses highly mobile ions in the crystal lattice and behaves as an ionic plastic crystal.
Abstract: An ionic coordination network consisting of protonated imidazole and anionic one-dimensional chains of Zn2+ phosphate was synthesized. The compound possesses highly mobile ions in the crystal lattice and behaves as an ionic plastic crystal. The dynamic behavior provides a proton conductivity of 2.6 × 10–4 S cm–1 at 130 °C without humidity.
TL;DR: In this article, the conductivity and viscosity of PEO/LiTFSI complexes are determined as a function of temperature, molecular weight (Mn) and the end group nature in view of the design of future polymer electrolytes.
TL;DR: In this article, the authors developed a new model called POLARIS to describe the complex conductivity of (pyrite-free) shaly poorly sorted sands, based on the solution given by the effective medium theory for grains coated by an electrical double layer and immersed in a background electrolyte.
Abstract: [1] I developed a new model named POLARIS describing the complex conductivity of (pyrite-free) shaly poorly sorted sands. This model is based on the solution given by the effective medium theory for grains coated by an electrical double layer and immersed in a background electrolyte. The electrical double layer comprises the Stern layer and the diffuse layer. Both layers play very distinct roles in the in-phase and quadrature conductivities. The polarization of the shaly sands is mainly controlled by the polarization of the Stern layer (except at very high salinities) with a very small mobility of the counterions contained in this layer. The in-phase component of the conductivity is controlled by the conductivity of the pore water with a contribution associated with the diffuse layer (the contribution of the Stern layer seems negligible). The fraction of counterions in the Stern layer is computed from a simple sorption isotherm and is used to infer the quadrature conductivity. The quadrature conductivity is assumed to be frequency independent, which is a reasonable approximation in clayey sands and sandstones, in agreement with observations. The polarization model is also based on the assumption that the Stern layer is discontinuous between grains, an assumption that is consistent with recent models of ionic transport in clayey sands. POLARIS explains the dependence of the quadrature conductivity on the salinity, cation exchange capacity, specific surface area (or specific surface per unit pore volume), and temperature. It can be used to predict the saturation and the permeability (inside 1 order of magnitude).
TL;DR: Liu et al. as discussed by the authors investigated lithium-ion electrode laminates as polymer composites to explain their performance variation due to changes in formulation and introduced a physical model in which AB and AM particles compete for polymer binder, which forms fixed layers of polymer on their surfaces.
Abstract: Author(s): Liu, G; Zheng, H; Song, X; Battaglia, VS | Abstract: This paper investigates lithium-ion electrode laminates as polymer composites to explain their performance variation due to changes in formulation. There are three essential components in a positive electrode laminate: active material (AM) particles, acetylene black (AB) particles, and the polymer binder. The high filler content and discrete particle sizes make the electrode laminate a very unique polymer composite. This work introduces a physical model in which AB and AM particles compete for polymer binder, which forms fixed layers of polymer on their surfaces. This competition leads to the observed variations in electrode morphology and performance for different electrode formulations. The electronic conductivities of the cathode laminates were measured and compared to an effective conductivity calculation based on the physical model to probe the interaction among the three components to reveal the critical factors controlling electrode conductivity and electrochemical performance. The data and effective conductivity calculation results agree very well with each other. This developed physical model provides a theoretical guideline for optimization of electrode composition for most polymer binder-based Li-ion battery electrodes. © 2012 The Electrochemical Society.
TL;DR: In this paper, the electrical transport properties of poly(3,4-ethylenedioxythiophen)/poly(4-styrene-sulfonate) (PEDOT:PSS) with PEDOT-to-PSS ratios from 1:1 to 1:30 were investigated.
Abstract: We have investigated the electrical transport properties of poly(3,4-ethylenedioxythiophen)/poly(4-styrene-sulfonate) (PEDOT:PSS) with PEDOT-to-PSS ratios from 1:1 to 1:30. By combining impedance spectroscopy with thermoelectric measurements, we are able to independently determine the variation of electrical conductivity and charge carrier density with PSS content. We find the charge carrier density to be independent of the PSS content. Using a generalized effective media theory, we show that the electrical conductivity in PEDOT:PSS can be understood as percolation between sites of highly conducting PEDOT:PSS complexes with a conductivity of 2.3 (Ωcm)−1 in a matrix of excess PSS with a low conductivity of 10−3 (Ω cm)−1. In addition to the transport properties, the thermoelectric power factors and Seebeck coefficients have been determined. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
TL;DR: In this article, a Pechini method was used to synthesize barium zirconate powders with high proton conductivity but poor chemical stability in presence of CO 2 as well as H 2 O.
TL;DR: In this paper, Cubic Li 6.25 La 3 Zr 2 Ga 0.25 O 12 powders were prepared from co-precipitated nitrate precursor and consolidated by hot-pressing to a relative density of ∼91%.
TL;DR: In this article, the formation and growth of argyrodite-type Li6PS5X (X = Cl, Br, I) using mechanical milling followed by annealing is investigated.
Abstract: All-solid-state rechargeable lithium-ion batteries (AS-LIBs) are attractive power sources for electrochemical applications due to their potentiality in improving safety and stability over conventional batteries with liquid electrolytes. Finding a solid electrolyte with high ionic conductivity and compatibility with other battery components is a key factor in raising the performance of AS-LIBs. In this work, we prepare argyrodite-type Li6PS5X (X = Cl, Br, I) using mechanical milling followed by annealing. X-ray diffraction characterization reveals the formation and growth of crystalline Li6PS5X in all cases. Ionic conductivity of the order of 7 × 10−4 S cm−1 in Li6PS5Cl and Li6PS5Br renders these phases suitable for AS-LIBs. Joint structure refinements using high-resolution neutron and laboratory X-ray diffraction provide insight into the influence of disorder on the fast ionic conductivity. Besides the disorder in the lithium distribution, it is the disorder in the S2−/Cl− or S2−/Br− distribution that we find to promote ion mobility, whereas the large I− cannot be exchanged for S2− and the resulting more ordered Li6PS5I exhibits only a moderate conductivity. Li+ ion migration pathways in the crystalline compounds are modelled using the bond valence approach to interpret the differences between argyrodites containing different halide ions.
TL;DR: In this article, the effects of the reaction time, the size of the interfacial area, scale ratio, and concentration of reactant on the crystalline structure, thermal stability, morphology, electrical conductivity and dielectric permittivity are systematically studied.
TL;DR: In this paper, the authors investigated the thermal conductivity of both zigzag and armchair graphene nanoribbons possessing different densities of Stone-Thrower-Wales (STW) defects.
TL;DR: In this article, the effect of water adsorption on the electrical properties of graphene oxide (GO) films using the direct current measurement and alternating current (AC) complex impedance spectroscopy was investigated.
Abstract: We investigate the effect of water adsorption on the electrical properties of graphene oxide (GO) films using the direct current (DC) measurement and alternating current (AC) complex impedance spectroscopy. GO suspension synthesized by a modified Hummer's method is deposited on Au interdigitated electrodes. The strong electrical interaction of water molecules with GO films was observed through electrical characterizations. The DC measurement results show that the electrical properties of GO films are humidity- and applied voltage amplitude-dependent. The AC complex impedance spectroscopy method is used to analyze the mechanism of electrical interaction between water molecules and GO films in detail. At low humidity, GO films exhibit poor conductivity and can be seen as an insulator. However, at high humidity, the conductivity of GO films increases due to the enhancement of ion conduction. Our systematic research on this effect provides the fundamental supports for the development of graphene devices originating from solution-processed graphene oxide.
TL;DR: A facile redox reaction between KMnO4 and MnSO4 was carried out to investigate the dielectric response and microwave absorbing properties of Ni/Co-doped MnO2 as discussed by the authors.
Abstract: A facile redox reaction between KMnO4 and MnSO4 was carried out to investigate the dielectric response and microwave absorbing properties of Ni/Co-doped MnO2. The samples were characterized by X-ray powder diffraction (XRD), X-ray fluorescence spectrometry (XRF), scanning electron microscopy (SEM), and vector network analysis. The analysis results revealed that the powders were α-MnO2 with one-dimensional nanostructure. The doping of Ni/Co had a certain effect on the dielectric properties: the relative complex permittivity showed a more distinct dielectric response characteristic, and the imaginary part exhibited a great enhancement of 2–18 GHz, which resulted in controllable wave-absorbing properties. The microwave absorbing bandwidth (RL < −10 dB) for Co-doped MnO2 was located at 10.96–16.13 GHz with a thickness of 2 mm. Furthermore, the Debye equation was introduced to explain the novel microwave dielectric response of doped MnO2. Some other properties derived from dielectric performances were also investigated, such as dielectric loss tangent and dielectric conductivity. In particular, first-principles calculations based on density functional theory (DFT) were used to uncover the relationship of electronic structure and dielectric properties on the microscopic scale.
TL;DR: The conductivity of Ca-doped BiFeO3 ceramics varies by many orders of magnitude, depending on the oxygen partial pressure during processing as mentioned in this paper, and it is known that the conductivity varies with the temperature.
Abstract: The conductivity of Ca-doped BiFeO3 ceramics varies by many orders of magnitude, depending on the oxygen partial pressure during processing. Bi1–xCaxFeO3–(x/2)+δ ceramics are mixed oxide ion/electr...
TL;DR: In this paper, the authors investigated the intrinsic defects in bulk multiferroic BiFeO3 and explore their implication for magnetization using a first-principles approach based on density functional theory.
Abstract: We investigate the energetics of the intrinsic defects in bulk multiferroic BiFeO3 and explore their implication for magnetization using a first-principles approach based on density functional theory. We find that the dominant defects in oxidizing (oxygen-rich) conditions are Bi and Fe vacancies and in reducing (oxygen-poor) conditions are O and Bi vacancies. The calculated carrier concentration shows that the BiFeO3 grown in oxidizing conditions has p-type conductivity. The conductivity decreases with oxygen partial pressure, and the material becomes insulating with a tendency for n-type conductivity. We find that the Bi and Fe vacancies produce a magnetic moment of ∼1μB and 5μB per vacancy, respectively, for p-type BiFeO3 and none for insulating BiFeO3 .O vacancies do not introduce any moment for both p-type and insulating BiFeO3. Calculated magnetic moments due to intrinsic defects are consistent with those reported experimentally for bulk BiFeO3.
TL;DR: In this article, the frequency dependence of dielectric and electric modulus as well as morphological characteristics of poly (∆-caprolactone) (PCL)-ammonium thiocyanate (NH 4 SCN) polymer electrolyte are investigated.
15 Feb 2012
TL;DR: Liu et al. as discussed by the authors investigated lithium-ion electrode laminates as polymer composites to explain their performance variation due to changes in formulation and introduced a physical model in which AB and AM particles compete for polymer binder, which forms fixed layers of polymer on their surfaces.
Abstract: Author(s): Liu, G; Zheng, H; Song, X; Battaglia, VS | Abstract: This paper investigates lithium-ion electrode laminates as polymer composites to explain their performance variation due to changes in formulation. There are three essential components in a positive electrode laminate: active material (AM) particles, acetylene black (AB) particles, and the polymer binder. The high filler content and discrete particle sizes make the electrode laminate a very unique polymer composite. This work introduces a physical model in which AB and AM particles compete for polymer binder, which forms fixed layers of polymer on their surfaces. This competition leads to the observed variations in electrode morphology and performance for different electrode formulations. The electronic conductivities of the cathode laminates were measured and compared to an effective conductivity calculation based on the physical model to probe the interaction among the three components to reveal the critical factors controlling electrode conductivity and electrochemical performance. The data and effective conductivity calculation results agree very well with each other. This developed physical model provides a theoretical guideline for optimization of electrode composition for most polymer binder-based Li-ion battery electrodes. © 2012 The Electrochemical Society.
TL;DR: In this article, the modulus data have been fitted using non-exponential Kohlrausch-Williams-Watts (KWW) function φ(t), and the value of the nonexponential parameter (β) is fairly low and nearly constant for different salt concentrations.
TL;DR: The effect of Mo doping on the crystal structure and thermal, electrical, and electrochemical properties of the SrCo1−xMoxO3−δ (x = 0.05, 0.1) system has been studied in this paper.
Abstract: The effect of Mo doping on the crystal structure and thermal, electrical, and electrochemical properties of the SrCo1–xMoxO3−δ (x = 0.05, 0.1) system has been studied. The introduction of Mo as a substitution for Co in SrCoO3−δ leads to a change from a hexagonal to a tetragonal perovskite structure at room temperature. The electrical conductivity is largely enhanced by the introduction of Mo at intermediate temperature due to the stabilization of the 3D-perovskite structure. However, the increase in Mo content decreases the total conductivity probably due to partial disruption of the electronic pathway. The use of these materials as cathodes in a solid-oxide fuel cell (SOFC) and as anodes in a solid oxide electrolyzer (SOE) has been evaluated, showing low values of electrode polarization resistances in both configurations over the intermediate temperature range. Interestingly, better performance was obtained under anodic polarization conditions reaching overpotential values as low as 28 mV for a current d...