| Since the broad application prospects of oxygen ion conductor in fuel cells, oxygensensors and solid-state devices, people carried out theoretical and experimental studiesare getting more depth and detailed, and has made many breakthroughs. Sr andMg-doped LaGaO3(LSGM) has a high ionic conductivity and good tolerance of theoxygen partial pressure in the low temperature region. The solid electrolyte material isconsidered to have great potential for development. Mg is introduced to improveconductivity in LaGaO3-based electrolyte. Because Mg2+radius is very close to Ga3+,making it easier to enter the crystal lattice; Mg2+is a divalent cation and excess oxygenvacancies can be produced. Mg2+is introduced to increase the solubility of Sr in Lasite.The series of LSGM has a high ionic conductivity in low temperature, can be morereadily applied to social production, but LSGM has a higher conductivity activationenergy itself, LaSrGa3O7and LaSrGaO4appear easily in the synthesis process etc.which need to be further studied. Only rare earth gallates LaGaO3, PrGaO3, NdGaO3can be synthesized at atmospheric pressure, while the doping PrGaO3and NdGaO3conductive dopant is smaller than the activation energy LaGaO3, Nd doped LaGaO3higher ionic transport number, it can be a Nd incorporated in the bit LSGM reduce itsconductivity activation energy, the electrical conductivity of the low-temperature regionLSGM.This paper was consider in solid state reaction of the LSGM and Nd-doped LSGMsolid electrolyte material and explores the microscopic mechanism of oxygen ionmigration in LaGaO3lattice.Step-scan XRD of La0.9Sr0.1Ga0.8Mg0.2O2.85showed its perovskite phase had beenformed which could be well fitted with the Pbnm group, and the corresponding latticeconstant were listed out. With increasing concentrations of Nd doped in LaGaO3thepeaks of XRD gradually toward the direction of high angle, since the Nd3+<La3+, whichresulted in the introduction of a lattice spacing of LaGaO3smaller, thus Nd had beenintroduced into the lattice of LaGaO3successfully.Sintering conditions such as temperature and holding time had a great influence onthe conductivity of the electrolyte LSGM system, sintered at temperatures between1300-1450°C impurity is easily produced, for different ratios of the samples, withdifferent sintering conditions suitable. Where in the conductive sampleLa0.9Sr0.1Ga0.8Mg0.2O31400°C,4h had the lowest activation energy as52.93kJ/mol,corresponding to the conductivity was higher than the other two sample which hold thetemperature for8or20hours. Dc conductivity activation energy was greater than the activation energy of the transition lattice needed. For La0.7Nd0.2Sr0.1Ga0.9Mg0.1O3conductivity at800°C are0.033S/cm,700°C,0.015S/cm, conductivity activationenergy of84.76kJ/mol, activation energy68.16kJ/mol.Solid electrolyte of LNSGM had a typical dielectric relaxation phenomena under theinfluence of an external electric field and the loss peak size did not change but shifted tohigher temperature with frequency increasing, the dynamic changed in the dielectricconstant sharp peak. For the series of Mg-10%, the Nd doped concentration had a littleinfluence on the low temperature of the loss peak, but larger peak on the hightemperature loss, as the doping concentration increasing of A and B sites, the dielectricloss summit splitting occured, this was due to the change of symmetry in the dopedoctahedral symmetry GaO6. |
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