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Li 1+x Al x Ti 2-x (PO 4 ) 3 (LATP) is a promising solid electrolyte for all-solid-state Li ion batteries. In this study, LATP is prepared through a sol-gel method using relatively the inexpensive reagents TiCl 4 . The thermal behavior, structural characteristics, fractured surface morphology, ion conductivity, and activation energy of the LATP sintered bodies are investigated by TG-DTA, X-ray diffraction, FE-SEM, and by an impedance method. A gelation powder was calcined at 500 Key words Li 1+x Al x Ti 2-x (PO 4 ) 3 , sol-gel, ion conductivity, solid electrolyte, activation energy. 서 론

LaCrO3 was prepared by using the polymeric precursor method for use as a receptor material and its NOx sensing characteristics were investigated. Nano-LaCrO3 powders were synthesized at the optimum compositions of the mole ratio of [La-, Cr-source]:[EG]:[AcAc] = [a, a]:[160 a]:[8 a] with 1 wt% polyvinylpyrrolidone (PVP) using ethylene glycol (EG) as a solvent, acetyl acetone (AcAc) as a chelating agent, and PVP as a polymer additive. The thermal decomposition behavior, crystal structure, morphology, and particle sizes of nano powders were characterized by a thermal analysis (TG-DTA), X-ray diffraction (XRD), a field emission scanning electron microscopy (FE-SEM), and a particle size analyzer, respectively LaCrO3 powders were mainly orthorhombic in structure and the primary particle size was 30 nm according to the XRD results. All solid-state compact impedancemetric-type sensor devices composed of Li1.5Al0.5Ti1.5(PO4)3 (LATP) as a transducer and a perovskite-type LaCrO3 nano powder as a receptor, have been investigated for their ability to detect NOx (NO and NO2) in the range of 1-250 ppm at 400 degrees C. The sensor device showed high gas sensitivities at NO gas, but relatively low gas sensitivities for NO2 gas.

KxNa(1−x)NbO3 particles (KNN, 0 < × < 1) were successfully synthesized through a facile glycothermal method by using KOH, NaOH and Nb2O5 as precursors and 1,4-butanediol as solvent at 200 °C for 12 h. The effects of varying the 1,4-butanediol/deionized water (B/W) volume ratio as solvent on the growth behavior, the morphological evolution, and the particle size of the synthesized KNN particles were investigated. In order to obtain K0.5Na0.5NbO3 with the morphotropic phase boundary (MPB) at the potassium content of x ≈ 0.5, the effect of varying K+/Na+ molar ratio on the composition of the obtained KNN particles was investigated. The crystal phase structure, morphology, particle size, chemical composition, and thermal behavior of the obtained particle samples were characterized using XRD, FE-SEM, EDS, TG, FT-IR, PSA, and TEM. The pure orthorhombic KNN particle close to NaNbO3 phase was obtained at the same concentration K+/Na+ of 1.0/1.0 and [K++Na+]/Nb molar ratio of 2.0/0.1. The synthesized K0.01Na0.99NbO3 particle exhibited a hexahedron shape with an average crystallite size of approximately 400 nm by glycothermal treated at 200 °C for 12 h. It is also demonstrated that the size of Na-rich KNN particles was decreased from 15 µm to 400 nm with increasing 1,4-butanediol content at various reaction conditions such as the volume ratio of B/W and can be controlled by 1,4-butanediol with an additive of water. Until the molar ratio of K+/Na+ reaches 1.6/0.4, the obtained particles have produced a Na-rich KNN phase, whereas when the molar ratio of K+/Na+ is 1.8/0.2, the particles could obtain a K-rich KNN phase. The results revealed that single-phase K0.5Na0.5NbO3 particles could be obtained at a relatively narrow molar ratio of K+/Na+ to 1.7/0.3. The particles with weakened agglomerate could obtain the average particle size of approximately 400 nm and a hexahedron shape. In comparison with the traditional hydrothermal method, the glycothermal method has been confirmed to be a more efficient method in controlling the particle size of KNN particles from micro- to sub-micron.

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