Nickel oxide and Sc-doped ZrO2 electrode material with a 1:1 wt % composition of NiO and Zr0.84Sc0.16O1.92 was synthesized via a single-step glycine-nitrate combustion method. Different glycine to nitrate (g/n) molar ratios of 0.27, 0.54, and 1.1 were used to investigate its effect on the structural, morphological, and electrical properties of the heat-treated samples. X-ray diffraction (XRD) patterns of the as-sintered samples for all the g/n ratios were indexed to cubic phases of NiO and ScSZ. Upon reduction at 700 °C, NiO was fully reduced to Ni. In-situ XRD patterns showed that the composite Ni/Zr0.84Sc0.16O1.92 electrode material retains its cubic structure at intermediate temperatures from 500 °C to 800 °C. High magnification scanning electron microscopy (SEM) images revealed that nanoparticles of Ni are also formed and situated at the surfaces of ScSZ grains, apart from agglomerated submicron particles of Ni. SEM and electron-dispersive spectroscopy mapping revealed interconnected grains of ScSZ oxide-ion conducting phase. From the calculated conductivity based on electrochemical impedance spectroscopy results, the 0.27 g/n ratio showed an order of magnitude-higher total conductivity among the other prepared samples.

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In this study, cathode and lithium-ion conducting solid electrolyte composite pellet with 1:1 wt. % composition of LiFePO4 and Li7-3XGaxLa3Zr2O12 (x = 0.1) (LiFePO4|Ga-LLZO) was prepared via solid-state reaction. The aim of the study is to investigate the phase stability between LiFePO4 cathode and Ga-LLZO solid electrolyte material when heat treated at 400 to 600 °C. The as-mixed LiFePO4|Ga-LLZO composite was characterized by TG/DTA and the heat treated sample was then analyzed for its structure using XRD and compared to the just as-mixed composite. XRD patterns of the heat treated composite pellet showed that it retains its as-mixed phases of LiFePO4 and Ga-LLZO when sintered below 500 °C under Ar gas flow environment. However, upon heat treatment at 600 °C, the sample already reacted and decomposed with the formation of other phases.

In this study, bulk lithium-ion conducting solid electrolyte of Ga-doped Li7La3Zr2O12 (Li7-3XGaxLa3Zr2O12) where x = 0.1 (Ga-LLZO) was prepared via hot pressing at 500 °C. Precursor powder for hot-pressing was prepared using conventional solid state reaction method. Planetary ball milling was employed to investigate the particle size effect on the structure and densification of hot-pressed samples. XRD patterns of the bulk hot-pressed sample revealed a crystalline phase of which the major peaks observed can be indexed to a cubic LLZO structure; however, a major impurity phase of La2Zr2O7 was observed for the ball-milled sample. Thermogravimetric and differential thermal analysis showed about 12% weight loss below 900 °C which may have affected the observed hot-pressing structure. Although lower density measurement and an impurity phase of La2Zr2O7 were observed for the ball-milled sample, ball-milling also resulted to a more homogeneous and finer particle size as shown by SEM images results.

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