Lanthanum-doped Strontium Titanate Research Articles

Study on thermoelectric properties and atomic-scale mechanism of B-site molybdenum-modified La0.1Sr0.9TiO3

Extensive studies on strontium titanate thermoelectric materials have shown that their poor conductivity results in a low ZT value. However, elemental doping can effectively improve the thermoelectric properties of these materials. In this study, a two-step sintering process was applied, using physical mixing to introduce 1 % molybdenum powder as a modification to the lanthanum-doped strontium titanate solid powder (La0.1Sr0.9TiO3). The obtained sample exhibited a maximum conductivity of 7830 S/m, with a maximum ZT of 0.12. Furthermore, this study combined experimental data with first-principles simulation calculations to elucidate the mechanism at the atomic scale. The incorporation of Mo6+ in place of Ti4+ at the B-site by molybdenum (Mo) adds two free electrons, leading to an elevated carrier concentration. This change concurrently reduces the Fermi level of the material and improves mobility, collectively resulting in a substantial increase in electrical conductivity. Phonon simulation indicated that Mo doping increased structural defects, thereby reducing lattice thermal conductivity. This significant enhancement in electrical conductivity and decrease in lattice thermal conductivity collectively increased the ZT value of the material.

Heterogeneity in La Distribution in Highly La-Doped SrTiO3 Crystals

Our paper is focused on the investigation of the dopant distribution in lanthanum-doped strontium titanate (LSTO) single crystals with a 5 wt.% doping level of La. Using X-ray diffraction analysis and pycnometric density measurement, we have found a discrepancy between the theoretical density and the experimentally determined value. The origin of this behavior could be either the creation of the voids in the matrix or the intergrowth of secondary phases with La surplus in the crystal. Transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and selected area diffraction (SAD) microscopic investigation have confirmed the second hypothesis, namely, that in different regions of LSTO, the local concentration of La shows a substantial variation on the micro- and nanoscopic scale. In order to study the influence of the La dopants on the electronic structure and, therefore, on the electrical conductivity, we have used the local conductivity atomic force microscopy (LCAFM) method as a local electrical probe to map the in-plane electrical conductivity of the La-doped crystal’s surface. The LCAFM conductivity maps reveal heterogeneous conductivity (here in the form of the bands with higher conductivity than the surroundings), related to band-like inhomogeneities of the La distribution. Using LCAFM measurements with atomic resolution obtained between the conducting and nonconducting regions, we analyzed the spreading (spatial expansion) of doping on the undoped or low-doped part of the STO crystal. The found limitation of the doping effect of La on the dielectric part of the STO crystal to 4–5 lattice constants was in good correlation with ab initio studies from the literature.

Techno-environmental analysis of material substitution in thermoelectric modules: non-oxide (bismuth telluride alloys) vs. oxide-based (lanthanum-doped strontium titanate and calcium cobaltite) materials

Techno-environmental analysis of material substitution in thermoelectric modules: non-oxide (bismuth telluride alloys) vs. oxide-based (lanthanum-doped strontium titanate and calcium cobaltite) materials

Reversible Solid Oxide Cells: Selection of Fuel Electrode Materials for Improved Performance and Durability

Different fuel electrodes for reversible solid oxide cells (r-SOC) are investigated with the aim of improving performance in both solid oxide electrolysis cell (SOEC) and solid oxide fuel cell (SOFC) modes, and durability in reversible operation mode. Electrodes based on gadolinium-doped ceria (GDC) as a mixed ionic electronic conductor, and lanthanum-doped strontium titanate (LST) as an electronic conductor are selected. The current-voltage characteristics of r-SOC single cells, and their cycling durability up to 1000 cycles are evaluated. LST-GDC co-impregnated with Ni and GDC prove to be highly durable in reversible operation, as a suitable fuel electrode material for r-SOCs.

Facile and composition controllable synthesis of lanthanum-doped strontium titanate via peroxide route

ABSTRACT Lanthanum-doped strontium titanate powder, La0.05Sr0.95TiO3+δ, was fabricated by peroxide-based route and calcination of freshly prepared precipitate and precipitate after ageing was carried out. The starting titanium precursor was titanium nitride, which underwent the reaction to form titanium peroxohydroxide and then compound containing strontium and lanthanum. A perovskite structure of strontium titanate with 5 mol-% doped lanthanum was obtained after calcination of the freshly-prepared precipitate at 500°C. However, the ageing powder revealed the presence of the second phase of strontium carbonate after calcination at the same condition. Thermogravimetric results showed that the decomposition of ammonia promoted a reaction to form the pure phase of ceramic oxide only in the freshly calcined sample.

Performance of Metal Supported SOFCs Operated in Hydrocarbon Fuels and at Low (

Solid oxide cells (SOCs) are a key enabling technology for the required future renewable energy systems by providing an efficient link between the power, gas, and heat sectors. Specifically, solid oxide fuel cells (SOFCs) convert the chemical energy of a fuel into electricity and heat with high electrical efficiencies. Hydrogen is the obvious choice of fuel due to the only emissions being steam, however hydrocarbon fuels are an interesting and safe alternative to hydrogen, especially for mobile applications, facilitating easy integration into existing infrastructure. The state-of-the-art (SoA) Ni:YSZ (yttria-stabilized zirconia) composite fuel electrode is capable of direct oxidation of hydrocarbons or of reforming of hydrocarbon gas mixtures. Unfortunately, the material that facilitates the above reactions, nickel, is also an excellent carbon deposition catalyst. This is problematic, due to the associated volumetric changes and reduction in electrochemically active sites. Ultimately, the fuel electrode can delaminate from the electrolyte, causing a catastrophic failure of the cell.Alternative fuel electrode materials are the key to avoid this. A-site deficient lanthanum doped strontium titanate (La0.4Sr0.4Fe0.03Ni0.03Ti0.94O3, LSFNT) based anodes, coated with Ni:CGO (gadolinium-doped ceria) electrocatalyst are a promising alternative - while avoiding Ni as a major part of the backbone, the infiltrated Ni ensures electrocatalytic activity. The co-infiltrated CGO serves to improve the ionic conductivity. Integrating these anodes into a metal supported (MS) design ensures lower cost and mechanical robustness. Full cells are manufactured through scalable tape casting and screen printing technology, including the metal support. Possible pitfalls for the MS-cell include vulnerability to corrosion of the metal support and decreased reforming activity due to less electrocatalyst (Ni) compared to the SoA-cell.In this study, the reforming activity of methane in 3 different SOFCs is investigated: Cell 1 is with a SoA Ni:YSZ anode, cell 2 is with a LSFNT anode and cell 3 is with a LSFNT-FeCr anode. The investigation involves electrochemical characterization by impedance spectroscopy (EIS) and performance under applied current (I/V-curves) at temperatures 750˚C, 700˚C, 650˚C and 620˚C, so-called fingerprints, with special emphasis on the anode activity for reforming and water gas shift reaction. Furthermore, galvanostatic durability tests are conducted for the MS-cells (cell 2 and cell 3) with focus on the durability at low temperature (650˚C) and corrosion resistance at medium to high fuel utilization (ca. 50%). The degradation of the tested cells is examined by comparing the electrochemical performance before and after durability testing.

Performance of Metal Supported SOFCs Operated in Hydrocarbon Fuels and at Low (

The Ni/YSZ composite electrode is conventionally used for solid oxide cells, in electrolysis (SOEC) as well as fuel cell (SOFC) operation. For enhanced durability and C-tolerance, alternative fuel electrode materials are needed. In this paper, we compare the performance of two distinct Ni:CGO electrocatalyst coated A-site deficient lanthanum doped strontium titanate (La0.4Sr0.4Fe0.03Ni0.03Ti0.94O3, LSFNT) based anodes, integrated into metal supported cells (MSCs), to the SoA Ni/YSZ anode supported cell in fuel cell mode for the first time. The three cells were investigated electrochemically by impedance spectroscopy (EIS) and performance under applied current (iV-curves) at temperatures 750˚C, 700˚C, 650˚C, and at novel 620˚C in steam/hydrogen and methane/steam. Additionally, one of the MSCs was investigated in CO/steam. Furthermore, galvanostatic durability tests were conducted in 4% steam/hydrogen for the MS-cells at low temperature (650˚C) at medium-high fuel utilization (50%).

Influence of nanometric microstructural development on thermophysical properties of lanthanum-doped strontium titanate

The evolution of imperfect crystal from a highly amorphous structure to an ordered crystalline structure via sintering has demonstrated a significant development onto the thermophysical properties. Therefore, a series of La-doped strontium titanate with different morphological properties have been synthesized via high energy ball milling with subsequent sintering. Doping of lanthanum tends to inhibit the grain growth where a significant reduction of grain size (range from 34 nm to 0.47 μm) could be observed. A large amount of grain boundaries presence with fine grains, resulting from lanthanum doping, has enhanced phonon scattering, thus yielding a low heat propagation in La-doped SrTiO3. Besides acting as a grain growth inhibitor, lanthanum also acts as a scattering centre due to imperfection created by the doping. The scattering mechanisms significantly decrease the phonon mean free path. Consequently, the thermal diffusivity has been efficiently reduced to 1.1 mm2/s as compared to that of pure SrTiO3 which showed a value of about 3.8 mm2/s, both observed for the complete phase polycrystalline materials. The systematic development of thermophysical and morphological properties of La-doped SrTiO3 can be served as a preliminary guide to engineer thermoelectric materials with low thermal diffusivity.

Plasma-sprayed lanthanum-doped strontium titanate as an interconnect for solid oxide fuel cells: Effects of powder size and process conditions

As a key component of the novel bi-layer interconnect for solid oxide fuel cells (SOFC), La-doped SrTiO3 (LST) has been deposited by atmospheric plasma spraying in this study. The effects of powder particle size, hydrogen flow rate and deposition temperature on stoichiometry, microstructure, and properties of LST deposits have been systematically investigated. The preferential vaporization loss of Sr is quantified by the relationship between the droplet size and splat composition, while the droplet size prior to impact is measured by a confocal laser microscopy and the composition of splat is analyzed by the energy-dispersive spectrum of scanning electron microscopy. Thermogravimetric analysis is used to determine the oxygen non-stoichiometry of the deposit. It is found that when the droplet diameter is smaller than 30 µm, the preferential vaporization induced Sr loss is significantly increased up to 45% with decreasing particle size, while it is greatly reduced if the droplet size is larger than 30 µm. Two mechanisms including diffusion-dominated mass transfer and convection-dominated mass transfer are proposed to explain the particle size effect on Sr loss. With increasing H2 flow in plasma gas, the oxygen deficiency in LST deposit is increased. Moreover, the effective bonding at lamellar interfaces is realized by increasing the deposition temperature to higher than the critical bonding temperature. The electrical conductivity of LST deposits is remarkably improved by decreasing Sr loss, increasing oxygen vacancy concentration, and enhancing the lamellar bonding. The LST coatings prepared at a deposition temperature of 450°C with coarse powder particles exhibits a dense microstructure and a conductivity of ~100 S/cm at 850°C in the reducing atmosphere. The results show that by properly optimizing the process conditions, the plasma-sprayed LST coating is a promising candidate to be a part of the bi-layer interconnect for SOFCs.

The structure of a new nano-phase of lanthanum-doped strontium titanate

A novel ordered phase in La-doped SrTiO3 was determined through three-dimensional electron diffraction studies. An overall stoichiometry of LaSr7Ti8O23 leads to a monoclinic structure with layers of square pyramids of TiO5 localised near the lanthanum substituted positions. The difference in crystal structure of the nanoprecipitates, particularly the connection of the rigid Ti–O frameworks, should affect the phonon interactions in the bulk material and so helps to explain a decrease in the lattice thermal conductivity in the La-doped SrTiO3, which is beneficial towards desired thermoelectric properties.

Lanthanum Doped Strontium Titanate Nanomaterial for Photocatalytic and Supercapacitor Applications

We report the synthesis of lanthanum doped strontium titanate (Sr1-xLaxTiO3,x=0.1) by sol-gel method. The physical properties of the as-synthesized sample were systematically studied through X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDAX). Diffraction peaks in XRD supported the cubic formation of perovskite-type crystal structure. The image analysis of nanomaterial by SEM and TEM techniques disclosed aggregates of nanoparticles with grain size about 20 nm. The study by UV-DRS exposed the band energy gaps (Eg) of 3.4 eV for strontium titanate nanoparticles, respectively. The degradation studies for three days were carried out for three dyes. Malachite green and rhodamine blue, strontium titanate nanoparticles showed utmost photocatalytic activity for rhodamine blue under UV light irradiation (from 0 to 80 min) as compared to malachite green. Properties of electrochemistry were looked into by cyclic voltammetry and galvanostatic charge/discharge in 1M KCl electrolyte. The Sr0.9La0.1TiO3 electrode displayed maximal specific capacitance of 306.74 F g-1 at current 1mA from galvanostatic charge-discharge curve. The rare earth doped perovskite Sr0.9La0.1TiO3 nanomaterial exhibited increased surface area with superior supercapacitance property.

Combined plasmonic Au-nanoparticle and conducting metal oxide high-temperature optical sensing with LSTO.

Fiber optic sensor technology offers several advantages for harsh-environment applications. However, the development of optical gas sensing layers that are stable under harsh environmental conditions is an ongoing research challenge. In this work, electronically conducting metal oxide lanthanum-doped strontium titanate (LSTO) films embedded with gold nanoparticles are examined as a sensing layer for application in reducing gas flows at high temperature (600-800 °C). A strong localized surface plasmon resonance (LSPR) based response to hydrogen is demonstrated in the visible region of the spectrum, while a Drude free electron-based response is observed in the near-IR. Characteristics of these responses are studied both on planar glass substrates and on silica fibers. Charge transfer between the oxide film and the gold nanoparticles is explored as a possible mechanism governing the Au LSPR response and is considered in terms of the corresponding properties of the conducting metal oxide-based matrix phase. Principal component analysis is applied to the combined plasmonic and free-carrier based response over a range of temperatures and hydrogen concentrations. It is demonstrated that the combined visible and near-IR response of these films provides improved versatility for multiwavelength interrogation, as well as improved discrimination of important process parameters (concentration and temperature) through application of multivariate analysis techniques.

Thermoelectric properties of A-site deficient La-doped SrTiO3 at 100–900 °C under reducing conditions

Lanthanum doped strontium titanate is a potential n-type thermoelectric material at moderate and high temperatures. (La0.12Sr0.88)0.95TiO3 ceramics were prepared by two different routes, conventional sintering at 1500 °C and spark plasma sintering at temperatures between 925 and 1200 °C. Samples with grain size between 40 nm and 1.4 μm were prepared and characterized with respect to their thermoelectric transport properties at temperatures between 100 and 900 °C under reducing conditions (H2/H2O-buffer mixtures). The thermal conductivity was significantly reduced with decreasing grain size reaching a value of 1.3 W m−1. K−1 at 600 °C for grain size of 40 nm and porosity of 19%. Electrical conductivity increased with increasing grain size showing a maximum of 500 S cm−1 at 200 °C for a grain size of 1.4 μm. The highest figure-of-merit (zT) was measured for samples with 1.4 μm average grain size reaching 0.2 at 500 °C.

Application of solid electrolyte cells in ion pump and electrolyzer modes to promote catalytic reactions: An overview

Solid electrolyte cells can be operated in three basic modes: fuel cell, electrolyzer and ion pump. In the fuel cell mode, a fuel such as hydrogen, CO and light hydrocarbons is electrochemically oxidized to generate power. Electrolyzer and ion pump modes, however, need application of power from an external source in order to perform the desired tasks. In this article, we present a brief overview of the studies that use an oxygen ion conducting electrolyte for catalytic applications, with two specific examples from our own studies: use of a solid electrolyte cell in the ion pump mode for alkane oxidative dehydrogenation and in the electrolyzer mode for CO2 reduction. The solid electrolyte cell assembly used in these studies consists of a button cell containing yttria-stabilized zirconia solid oxide electrolyte, a modified strontium titanate (ST) catalyst as the working electrode, i.e., anode for the ODH reaction and cathode for the CO2 reduction reaction, and a lanthanum strontium manganite (LSM) catalyst as the counter electrode.Physical properties of the titanate materials were studied using XRD, conductivity measurement and temperature-programmed oxidation with CO2. Lanthanum doped strontium titanate (La0.2Sr0.8TiO3±δ), with or without Cl, was seen to have a higher electrical conductivity compared to un-doped strontium titanate (SrTiO3). Cl doping, however, was seen to improve the electrocatalytic activity for both ODH and CO2 reduction reactions, giving higher yields of ethylene and CO compared to Cl-free La0.2Sr0.8TiO3±δ. The comparison of the catalytic and electrocatalytic ODH reactions clearly pointed out that oxygen in ionic form was more selective to ethylene than molecular oxygen at similar conversion values.

Lanthanum doped strontium titanate - ceria anodes: deconvolution of impedance spectra and relationship with composition and microstructure

Electrochemical performance of ceramic (Ni-free) SOFC anodes based on La0.2Sr0.7TiO3-δ (LST) and Gd0.1Ce0.9O1.95-δ (CGO) is thoroughly investigated. Microstructures and compositions are systematically varied around the percolation thresholds of both phases by modification of phase volume fractions, particle size distributions and firing temperature. Differential impedance spectroscopy was performed while varying gas composition, electrical potential and operating temperature, which allows determining four distinct electrode processes. Significant anode impedances are measured at low frequencies, which in contrast to the literature cannot be linked with gas concentration impedance. The dominant low frequency process (∼1 Hz) is attributed to the chemical capacitance. Combined EIS and microstructure investigations show that the chemical capacitance correlates inversely with the available surface area of CGO, indicating CGO surface reactions as the kinetic limitation for the dominant anode process and for the associated chemical capacitance. In anodes with a fine-grained microstructure this limitation is significantly smaller, which results in an impressive power output as high as 0.34 Wcm−2. The anodes show high redox stability by not only withstanding 30 isothermal redox cycles, but even improving the performance. Hence, compared to conventional Ni-cermet anodes the new LST-CGO material represents an interesting alternative with much improved redox-stability.

Infiltrated La0.4Sr0.4Fe0.03Ni0.03Ti0.94O3 based anodes for all ceramic and metal supported solid oxide fuel cells

For improved robustness, durability and to avoid severe processing challenges alternatives to the Ni:YSZ composite electrode is highly desirable. The Ni:YSZ composite electrode is conventionally used for solid oxide fuel cell and solid oxide electrolysis cell. In the present study we report on high performing nanostructured Ni:CGO electrocatalyst coated A site deficient Lanthanum doped Strontium Titanate (La0.4Sr0.4Fe0.03Ni0.03Ti0.94O3) based anodes. The anodes were incorporated into the co-sintered DTU metal supported solid oxide fuel cell design and large sized 12 cm × 12 cm cells were fabricated. The titanate material showed good processing characteristics and surface wetting properties towards the Ni:CGO electrocatalyst coating. The cell performances were evaluated on single cell level (active area 16 cm2) and a power density at 0.7 V and 700 °C of 0.650 Wcm−2 with a fuel utilization of 31% was achieved. Taking the temperature into account the performances of the studied anodes are among the best reported for redox stable and corrosion resistant alternatives to the conventional Ni:YSZ composite solid oxide cell electrode.

Electronic structural, optical and phonon lattice dynamical properties of pure- and La-doped SrTiO3: An ab initio thermodynamics study

To better understand the electronic, optical, and thermodynamic behaviors of lanthanum doped strontium titanate (La-STO) with different doping levels at high temperature, ab initio thermodynamics have been employed to investigate their electronic structures and thermodynamic evolutions versus temperatures. The results show that with increasing La-doping level, the corresponding structures of La-STO become less stable with an increasing number of phonon soft modes. The calculated thermodynamic properties show that with increasing La-doping levels, the free energy and enthalpy changes of La-STOs are decreased at given temperature. For all La-STOs with different La-doping levels investigated, we found that in three cases doping with 25%, 37.5% and 75% La substituted for Sr, the diagonal elements of their dielectric constant matrix are not all equal, which means these crystal structures are uniaxial and anisotropic. Our results indicate that doping La into STO could alter the optical properties of pure STO to be birefringent.

On the manufacturing of low temperature activated Sr0.9La0.1TiO3-δ-Ce1-xGdxO2-δ anodes for solid oxide fuel cell

Lanthanum doped strontium titanate–gadolinium doped cerium oxide (LST-GDC) anodic layers are sintered in air and further reduced in-situ at low temperature (750°C) avoiding usually performed pre-reduction treatment at high temperature. The influence of various milling techniques and of powders with different specific surface area, on the microstructures of screen-printed anodes, is investigated. The combination of milling and sonication processes is efficient in reducing aggregation of the anode powders. The anode performance is improved when a planetary milling step is involved in the preparation of the screen printing inks. The use of gadolinium doped cerium oxide with high specific surface area decreases the polarization resistance. The rate of hydrogen oxidation is also enhanced by increasing porosity.

Theoretical Investigation of the Electronic, Structural, Optical and Thermodynamic Properties of LaxSr1-xTiO3 (x=0, 0.125, 0.25)

Lanthanum doped strontium titanate (La1-xSrxTiO­3, La-STO) materials are essential for solid oxide fuel cell (SOFC) electrodes and high-temperature gas sensors.[1] In the literature, their electronic structures and optical properties have been investigated intensively by density functional theory (DFT). However, the obtained information is theoretically limited to low temperature because the traditional DFT approach doesn’t include temperature effects. Since many of the applications of these materials for SOFCs and sensors are 400-800°C range, it is very important to know how their properties change when operating at high-temperatures. To better understand the thermodynamic behavior of La-STO with different La-doping levels at high temperatures, the ab initio thermodynamics calculations which combine first-principles DFT with lattice phonon dynamics have been employed in this study to calculate their electronic structures and thermodynamic evolutions versus temperature.[2-5] The obtained results show that with increasing La-doping level, the corresponding structures of La-STO become unstable with an increasing number of soft modes, especially when the La content over Sr is higher than 25%.[6] The La-STOs are conductors even at T=0K due to the electron of La filling in the conduction band of STO, which is consistent with experimental results. The results also reveal that although the GGA+U method could predict the band-gap of STO closer to the experimental measurements, the predicted lattice parameters of La-STO are larger than experimental values and result in more phonon soft modes. These deviations demonstrate the limitations of such U corrections for property extrapolation to high temperatures in comparison with the standard GGA approach. From the calculated optical dielectric tensors of La-STO, one can see that in the optical frequency range, there is a major difference between pure STO and La-doped STO consistent with the dielectric nature of STO and the finite electrical conductivity in La-doped STO associated with electrons in the conduction band, and consistent with expectations from experiments and simple Drude theory arguments. The reason is that STO possesses a band-gap, while La-doped STOs do not have a band-gap, as the extra electrons occupy the conduction band of STO. Due to the reduced symmetry for the La-doped STO systems, the diagonal elements (εXX, εYY, εZZ) of the dielectric matrix are not equal for some of La-STOs. Related to the DFT energy of pure STO, the calculated thermodynamic properties show that with increasing La-doping levels, the ΔH(T) and ΔG(T) decrease at given temperature T. With increasing T, the ΔH(T) of each La-STO increases while its ΔG(T) decreases because of the effects of TΔS(T) term. These results are useful for understanding the thermodynamic behaviors of La-STO materials at high temperatures and guide further studies of SOFC electrodes and sensor materials.

Atmospheric Plasma-Sprayed La0.3Sr0.7TiO3 - δ Interconnect for High-Temperature Solid Oxide Fuel Cells

Lanthanum-doped strontium titanate (La0.3Sr0.7TiO3 - δ, LST) perovskite is regarded as a promising candidate for high-temperature solid oxide fuel cells (HT-SOFCs) interconnect material due to its good phase stability, good thermal expansion matching to other components, as well as high electrical conductivity in reducing atmosphere. Atmospheric plasma spraying (APS) is a cost-effective processing method to fabricate membranes in SOFCs. However, the LST coatings deposited following the conventional routine exhibit a typical lamellar structure with a limited interlamellar bonding, which dominates the properties of interconnect including gas tightness and electrical conductivity. Besides, the preferential evaporation of Sr during plasma spraying may degrade the performance of LST coatings as interconnect for HT-SOFCs. In this paper, dense LST membranes were deposited on YSZ substrates at preheated conditions by APS. The effect of particle size of LST powders on the chemical composition, phase composition, and electrical conductivity of LST coatings were studied. It was found that the columnar grain growth across lamellar interfaces in LST coatings at the deposition temperature of ~500 °C was highly enhanced with increased interlamellar bonding ratio. Moreover, when the LST particle size is <30 μm, the evaporation of Sr increased remarkably with the decreasing of particle size. When the the LST particle size is ＞30 μm, the evaporation loss of Sr in LST coatings was greatly reduced. A vortex convection model of LST droplets during the spraying process was built to explain the effect of particle size on Sr evaporation. The electrical conductivity and stability of the LST interconnects were tested at controlled atmospheres at an operating temperature of 850 °C. The results show that the electrical conductivity of dense LST coatings prepared with large particles was greatly improved. The LST coatings exhibited excellent phase stability in both reducing and oxidizing atmospheres. Results suggest that LST interconnect with high performance can be deposited by APS through optimizing the microstructure and controlling the chemical composition.