Study on GDC-LSGM composite electrolytes for intermediate-temperature solid oxide fuel cells

Microstructure and electrical conductivity of La0.9Sr0.1 Ga0.8Mg0.2O2.85‐Ce0.8Gd0.2O1.9 composite electrolytes for SOFCs

“…On the other hand, composite electrolytes, a type of promising alternative electrolyte materials, have been considered to take advantages of single‐component electrolytes in the perspective of conductivity and stability, because they can compensate the weakness of single‐component electrolytes to a certain extent. In literature, Li et al reported that the composite electrolytes of Ce 0.9 Gd 0.1 O 1.9 matrix with the addition of La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 in a content of 5‐15 wt.% had a slightly lower grain bulk conductivity but a far higher grain boundary conductivity than pure Ce 0.9 Gd 0.1 O 1.9 at a temperature of 300 ~ 550°C, because the grain size of Ce 0.9 Gd 0.1 O 1.9 ‐La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 was greatly increased and thus the area of the grain boundary was remarkably decreased. Similar phenomena have been also reported on 90 wt.% Ce 0.85 Sm 0.15 O 1.9 ‐ 10 wt.% (La 0.95 Sr 0.05 ) x Ga 0.9 Mg 0.1 O 3−δ ( x = 0.97‐1.03) and x wt.% Ce 0.8 Nd 0.2 O 1.9 ‐ (100‐ x ) wt.% La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 2.85 ( x = 85‐95) composite electrolytes .…”

“…These phenomena imply that a chemical reaction correlated with the inter‐diffusion of LSGM and GDC components has occurred. The increase in d GDC can be attributed to the substitution of larger La 3+ (0.1160 nm) and Sr 2+ (0.1260 nm) for Ce 4+ (0.097 nm) and Gd +3 (0.1079 nm) in the GDC phase . And the diffusion of La 3+ ions from LSGM to GDC might present a major contribution, which could be further confirmed by the microstructural analysis presented in the next section.…”

Electrical Behavior of Lanthanum Aluminate (LAO) and Gadolinium Doped Ceria (GDG) Composite Electrolyte for Electrochemical Devices

“…The XRD pattern of sintered composite pellets consists of perovskite rhombohedral structure (R-3c) LAO as a major phase along with minor GDC cubic fluorite structure (space group, Fm3m). Peaks were indexed using the above-mentioned space group [16,38]. Using the Archimedes principle, the densities of sintered composite pellets were measured at 6.4, 6.6, and 6.7g/cm 2 for L3G1, L2G2, and L1G3, respectively, which is 97% of the theoretically calculated va;ues.…”

“…Using Scherer's formula, the average crystallite size was calculated to be in the 40-50nm range [16]. The structure with a smaller particle size or a large grain boundary has more oxygen vacancies resulting in higher conductivity [13,19,38]. The Energy-Dispersive Spectroscopy (EDS) study, shown in Figure 4, shows all the atomic constituents and their atomic percentage.…”

Ionic Conductivity of Doped Lanthanum Gallate and Strontium Gallate Composites

“…Recently, composite electrolytes have been investigated as alternative materials for SOFCs taking advantage of specific properties of every component. Most of reported studies involve well-known solid electrolytes as yttria-stabilized zirconia, doped-ceria and doped lanthanum gallate (7)(8)(9). In these previous studies, improvement of the electrical or mechanical properties is claimed.…”