Effect of Strontium the phase structure of Ba1−xSrxCe0.65Zr0.2Y0.15O3−δ (0 ≤ x ≤ 0.25) proton conductor by citrate–EDTA complexing sol–gel method

Proton conducting oxides Ba1−xSrxCe0.65Zr0.2Y0.15O3−δ (0 ≤ x ≤ 0.25) are prepared using the citrate–EDTA complexing sol–gel method. The effect of strontium and yttrium doping on the material properties is systematically investigated. The phase formation, thermal analysis, morphology, stability and conductivity measurements are performed on the sintered powders through TG–DTA, XRD, SEM, EDAX, FTIR, Raman and LCR measurements. The results indicated a single-phase orthorhombic system. Strontium incorporation helped in increasing the grain size up to 20% of strontium doping while reducing the lattice parameters and unit cell volume. The ionic conductivities of the Ba1−xSrxCe0.65Zr0.2Y0.15O3−δ sintered oxides increased with increase in the concentration of Sr2+ along with the co-doping strategy of trivalent Y3+ in the B site. Among the synthesized samples, Ba0.8Sr0.2Ce0.65Zr0.2Y0.15O3−δ pellet with orthorhombic structure showed highest conductivity with a value of 2.35 × 10−1 S/cm and 2.41 × 10−1 S/cm at 500 °C due to its smaller lattice volume, larger grain size and lower activation energy that led to excessive increase in conductivity. All pellets exhibited good chemical stability when exposed to air and H2O atmospheres. These results indicate that this composition can be used as a potential electrolyte if synthesis conditions and temperature are well maintained

Effect of strontium on Nd doped Ba1−xSrxCe0.65Zr0.25Nd0.1O3−δ proton conductor as an electrolyte for solid oxide fuel cells

This paper investigated the Sr doping effect on the microstructure, chemical stability, and conductivity of Ba1−xSrxCe0.65Zr0.25Nd0.1O3−δ (0 ⩽ x ⩽ 0.2) electrolyte prepared by sol-gel method. The lattice constants and unit cell volumes were found to decrease as Sr atomic percentage increased in accordance with the Vegard law, confirming the formation of solid solution. Incorporation of Sr into the composition resulted in smaller grains besides suppressing the formation of secondary phases of SrCeO3. Among the synthesized samples BaCe0.65Zr0.25Nd0.1O3−δ pellet with orthorhombic structure showed highest conductivity with a value of 2.08 × 10−3 S/cm(dry air) and 2.12 × 10−3 S/cm (wet air with 3% relative humidity) at 500 °C due to its smaller lattice volume, larger grain size, and lower activation energy that led to excessive increase in conductivity. Ba0.8Sr0.2Ce0.65Zr0.25Nd0.1O3−δ recorded lower conductivity with a value of 4.62 × 10−4 S/cm (dry air) and 4.83 × 10−4 S/cm (wet air with 3% relative humidity) at 500 °C than Sr undoped but exhibited better chemical stability when exposed to air and H2O atmospheres. Comparisons with the literature showed the importance of the synthesis method on the properties of the powders. Hence this composition can be a promising electrolyte if all the values such as sintering temperature, Sr dopant concentration, and time are proportionally controlled

Synthesis, structural and electrical studies of Ba1−xSrxCe0.65Zr0.25Pr0.1O3−δ electrolyte materials for solid oxide fuel cells

This paper is discussed Sr doping effect on the microstructure, chemical stability and conductivity of Ba1−xSrxCe0.65Zr0.25Pr0.1O3−δ (0 ≤ x ≤ 0.2) electrolyte prepared by sol–gel method. The lattice constants and unit cell volumes are found to decrease as Sr atomic percentage increased in accordance with the Vegard law, confirming the formation of solid solution with orthorhombic structure. Among them all the synthesized samples are showed a conductivity with different atmosphere values at 500 °C. Ba0.92Sr0.08Ce0.65Zr0.25Pr0.1O3−δ recorded highest conductivity with a value of 3.3 × 10−6 S/cm (dry air) & 3.41 × 10−6 S/cm (wet air with 3% relative humidity) at 500 °C due to its smaller lattice volume, larger grain size and lower activation energy that led to excessive increase in conductivity. All pellets exhibited good chemical stability when exposed to air and H2O atmospheres. This study elucidates that the composition will be a promising electrolyte material for use as SOFC at intermediate temperatures if Sr doping is limited to small amounts. Keywords: Solid oxide fuel cell, Proton conducting electrolyte, Chemical stability, Sol–gel synthesis, BaCeO

Chemically stable proton conducting doped BaCeO3 by citrate-EDTA complexing sol-gel process for solid oxide fuel cell

Proton conducting oxides Ba1-xSrxCe0.65Zr0.25Y0.1O3-δ are prepared using the citrate-EDTA complexing sol-gel method. The effect of strontium and yttrium doping on the material properties are systematically investigated using TG/DTA, XRD, SEM, EDAX, FTIR, RAMAN and LCR measurments. The results indicated a single phase orthorhombic system. Strontium incorporation helped in increasing the grain size while reducing the lattice parameters and unit cell volume. The ionic conductivities of the sintered oxides increased with increase in the concentration of Sr2+ along with the co doping strategy of trivalent Y3+ in B site. In the present work at 500 °C, exhibited high conductivity value of 2.25 × 10−3 S/cm with activation energy of 0.38 eV in wet atmosphere. These results indicate that this composition can be used as a potential electrolyte if synthesis conditions and temperature are well maintained. Keywords: Solid oxide fuel cell, Proton conducting electrolyte, Chemical stability sol-gel synthesis, Ba1-xSrxCe0.65Zr0.25Y0.1O3-δ, Perovskit

Structural, morphological, impedance and magnetic studies of nanostructured LiNi0.45M0.1Mn0.45O2 (MCu and Al) cathode materials for lithium-ion batteries

Layered structure LiNi0.45M0.1Mn0.45O2 (MCu and Al) cathode materials for lithium-ion batteries are synthesized by solâgel auto combustion method. The structural, morphological, electrical and magnetic properties are examined by X-ray diffraction (XRD), field effect scanning electron microscope FESEM, FT-IR, EIS and ESR. XRD data revealed the rhombohedral and α-NaFeO2 structure with a space group R-3m. The electrical conductivity, dielectric constant, and dielectric loss are measured in the room temperature at a frequency ranging from 20 Hz to 1 MHz. The electrical conductivity of the compound is measured by AC impedance. An effective improvement in the electrical conductivity of order 5.42 Ã 10â6 S/cm is observed for the copper doped LNMO compounds. ESR spectra is recorded at room temperature on a Bruker EMX model X-band spectrometer operating at a frequency of 9.50 GHz. The critical dopants of Cu, with minimum g-factor and maximum line-width (W) are observed. Keywords: Solâgel, FESEM, AC impedance, ES