Development of Doped Lanthanum Gallate Solid Electrolytes

Development of the doped lanthanum gallate solid electrolytes in the recent years was reviewed. The structure and oxygen ion transference mechanism were discussed. Effects of alkali earths, transition metals, and impurities on electrical conductivity of the doped lanthanum gallates were also discussed. The applications of doped lanthanum gallate were described. The current problems and corresponding strategies were explored.

Preparation and Properties of Doped Lanthanum Gallate Film on a Ni/SDC Porous Anode Support

A 65. 8-μm dense doped lanthanum gallate La0.8Sr0.2 Ga0.85 Mg0.15 O2.825（LSGM）film was prepared on a porous Ni/SDC（samarium doped ceria, Ce0.8Sm0.2O1.9 ） anode support by colloid susponsion deposition with incomplete crystallization LSGM powder as a starting material. The phase composition and micromorphology of the LSGM film were characterized by X-ray diffraction and scanning electron microscopy. The electrical properties of the LSGM film and the performances of the LSGM film solid oxide fuel cell were also analyzed. The results show that beth the dense LSGM film on the porous anode support, and the required phase composition of the LSGM film were obtained simultaneously by sintering at 1400 ℃ for 6 h. The adhesion between the LSGM film and the porous anode support is very strong. The electrical conductivities of the LSGM film on the porous anode support are 0. 113 and 0. 173 S/cm at 800 and 850℃, respectively. The maximum output power density of the LSGM film cell is 177 mW/cm^2 at 700℃.

Structure and Electrical Conductivity of Compositely Doped Oxide Solid Electrolyte La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.12)Co_(0.08)O_(2.8)

(La, Sr)(Ga, Mg)O3-δ, (LSGM) perovskite compositions doped with transition metal Co on the B-site were prepared by solid state reaction. The effect of partial substitution of Ga for Co, La0.8Sr0.2Ga0.8Mg0.12Co0.08O2.8 (LSGMC2008) on the electrical conductivity was discussed. The results showed the compacted samples sintered at 1350 ℃ possesses increased electrical conductivity at low temperatures. The XRD patterns of the title materials indicated that LSGMC2008 possessed orthorhombic perovskite-type structure. The grains distributed relatively uniform from SEM photo. The Arrhenius plots of ionic conductivity in air of the LSGMC2008 exhibited differing slopes in the low-and high-temperature regions, and the corresponding Ea values were much lower than that of LSGM2020. All of these suggested that even at low sintering temperature, proper amount Co doped was beneficial to improve ionic conductivity of LSGM.

Oxygen ion conductivity of La_(0.8)Sr_(0.2)Ga_(0.83)Mg_(0.17-x)Co_xO_(3-δ) synthesized by laser rapid solidification

Materials Lao.8Sro.2Gao.83Mgo.17_xCox03_6 with x = 0, 0.05, 0.085, 0.10, and 0.15 are synthesized by laser rapid solidification. It is shown that the samples prepared by laser rapid solidification give rise to unique spear-like or leaf-like microstructures which are orderly arranged and densely packed. Their electrical properties each show a general depen dence of the Co content and the total conductivities of Lao.8Sro.2Gao.83Mgo.085Coo.08503_6 prepared by laser rapid solidification are measured to be 0.067, 0.124, and 0.202 S.cm-1 at 600, 700, and 800 ℃, respectively, which are much higher than by conventional solid state reactions. Moreover, the electrical conductivities each as a function of the oxy gen partial pressure are also measured. It is shown that the samples with the Co content values 〈 8.5 mol% each exhibit basically ionic conduction while those for Co content values 〉 10 mol % each show ionic mixed electronic conduction under oxygen partial pressures from 10-16 atm （1 atm = 1.01325 x 105 Pa） to 0.98 atm. The improved ionic conductivity of Lao.sSro.2Gao.83Mgo.085Coo.08503 prepared by laser rapid solidification compared with by solid state reactions is attributed to the unique microstructure of the sample generated during laser rapid solidification.

Optical,thermal and luminescence properties of La2O3-Ga2O3-ZrO2 glasses co-doped with Tm3+/Yb3+prepared by containerless technique

Bulk LaO-GaO-ZrO(LGZ)glass and Tm/Ybco-doped LGZ glasses were synthesized successfully using containerless technique.Raman spectra result reveals that the matrix sample possesses the low maximum phonon energy of~642 cm.The glasses show good compatibility between large Abbe numbers(>31)and high refractive indices(n>1.93).Moreover,transmittance measurements reflect that the glasses have high infrared transmittance of-81.9%,small OHabsorption coefficient and long mid-infrared cut-off wavelengths(-7.5μm).The surface morphology of host glass was characterized by scanning electron microscopy(SEM)micrograph and energy dispersive spectroscopy(EDS)tests reflect that the doped compositions are distributed into the matrix glass homogeneously.The results of thermal analysis show that the glasses have good thermal properties(T>769℃).Excited by 980 am laser,an intense 1810 am fluorescence is obtained originating from the transition:~3 E→~3 Hof Tmion,accompanied by upconversion emission.It can be observed that 1810 nm fluorescence has the highest intensity at 1 mol%YbOand owns broad full width at half-maximum(>245 nm),the luminescence intensity of~3 F→~3 Htransition increases with rising temperature from 300 to 550 K.Furthermore,the value of energy transfer efficiency shows that Ybcan transfer energy to Tmeffectively.By fitting the attenuation curves,the lifetimes of 1810 and 474 nm emission can be acquired.