Development by Mechanochemistry of La0.8Sr0.2Ga0.8Mg0.2O2.8 Electrolyte for SOFCs

Abstract

In this work, a mechanochemical process using high-energy milling conditions was employed to synthesize La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ (LSGM) powders from the corresponding stoichiometric amounts of La 2 O 3 , SrO, Ga 2 O 3 , and MgO in a short time. After 60 min of milling, the desired final product was obtained without the need for any subsequent annealing treatment. A half solid oxide fuel cell (SOFC) was then developed using LSGM as an electrolyte and La 0.8 Sr 0.2 MnO 3 (LSM) as an electrode, both obtained by mechanochemistry. The characterization by X-ray diffraction of as-prepared powders showed that LSGM and LSM present a perovskite structure and pseudo-cubic symmetry. The thermal and chemical stability between the electrolyte (LSGM) and the electrode (LSM) were analyzed by dynamic X-ray diffraction as a function of temperature. The electrolyte (LSGM) is thermally stable up to 800 and from 900 • C, where the secondary phases of LaSrGa 3 O 7 and LaSrGaO 4 appear. The best sintering temperature for the electrolyte is 1400 • C, since at this temperature, LaSrGaO 4 disappears and the percentage of LaSrGa 3 O 7 is minimized . The electrolyte is chemically compatible with the electrode up to 800 • C. The powder sample of the electrolyte (LSGM) at 1400 • C observed by HRTEM indicates that the cubic symmetry Pm-3m is preserved. The SOFC was constructed using the brush-painting technique; the electrode-electrolyte interface characterized by SEM presented good adhesion at 800 • C. The electrical properties of the electrolyte and the half-cell were analyzed by complex impedance spectroscopy. It was found that LSGM is a good candidate to be used as an electrolyte in SOFC, with an Ea value of 0.9 eV, and the LSM sample is a good candidate to be used as cathode.

Electrical and reaction performances of packed‐bed plasma reactors moderated with ferroelectric or dielectric materials

“…The inset shows photographs of real barriers utilized in this study voltage of 0.2 × V rms applied between the two SS electrodes. Nyquist plots [27,28] were obtained for each examined moderator material, based on the data retrieved from these experiments. Impedance measurements and Nyquist plots were taken at different imposed temperatures, from 25°C up to 144°C, that is, at temperatures lower and higher than the Curie temperature of BaTiO 3 , respectively.…”

Recent Progress in the Design, Characterisation and Application of LaAlO3- and LaGaO3-Based Solid Oxide Fuel Cell Electrolytes

“…The chemical compatibility of La 1−x Sr x Ga 1−y Mg y O 3−δ was investigated with oxide materials used in SOFCs, cathodes [141][142][143][144][145][146][147][148][149][150][151][152] and anodes [153][154][155][156][157][158][159][160][161][162][163][164][165][166][167]: this is presented in the corresponding reviews [28,56,153].…”

A Novel, Simple and Highly Efficient Route to Obtain PrBaMn2O5+δ Double Perovskite: Mechanochemical Synthesis

“…Mechanochemistry has shown to be an efficient, reproducible, and relatively simple way to obtain mixed oxides with simple perovskite structure that can be used as components in SOFCs [28][29][30][31][32][33]. This methodology is based on the induction of solid-state reactions at room temperature by applying mechanical energy (instead of heating) to a reactant powder mixture using primarily high-energy ball milling equipment.…”