Densification, morphological and transport properties of functional La1–xBaxYbO3– ceramic materials

Abstract

The effective operation of protonic ceramic electrochemical cells requires the design of electrolytes having not only high ionic conductivity, but also excellent stability with respect to carbonisation. In the present work, the La-based oxides (La 1-x Ba x YbO 3-δ, 0.03 ≤ x ≤ 0.10) are proposed as a possible alternative to the convenient Ba (Ce,Zr)O 3-based electrolytes due to their high chemical stability. It was discovered that Ba-doping results in a deterioration of sintering behaviour; as a result, the relative density decreases and open porosity appears (for x = 0.10). A thorough analysis of transport properties by means of AC and DC measurement techniques enables a selection of the La 0.97 Ba 0.03 YbO 3-δ sample, which demonstrates the highest conductivity compared with those samples where x = 0.5 and 0.10. Due to its excellent densification behaviour, stability and ionic conductivity, La 0.97 Ba 0.03 YbO 3-δ can be considered as a promising proton-conducting electrolyte in the La-based family.

Densification and Proton Conductivity of La1-xBaxScO3-δ Electrolyte Membranes

“…where Ba / are Ba dopant atoms in La regular lattice positions, O are oxygen atoms in regular lattice positions, V •• are oxygen vacancies, and OH • are proton defects. The perovskite group of the A 3+ B 3+ O3 type, such as La1-xMxBO3-δ (where M = Ca, Sr, Ba; B = Y, Yb, Sc, In) [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], are promising ceramic proton conductors because they have…”

“…a significant advantage over the widely studied materials based on Ba(Zr,Ce)O3 due to the tendency of Ba to carbonize [28][29][30]. Systematic studies of the transport properties of La1-xMxBO3-δ demonstrate a tendency for an increase in proton conductivity with an increase in the ionic radius of the dopant and a decrease in the ionic radius of the B-cation [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]; thus, the highest proton conductivity should be realized in La1-xBaxScO3-δ.…”

“…On the example of La1-xBaxYbO3-δ, it was shown that even the use of a small amount of Ba can complicate the sintering of ceramics. Kasyanova et al [26] showed that the sintering of La1-xBaxYbO3-δ (x = 0.03-0.1) ceramics significantly deteriorates at 1400 °C (5 h) at a concentration of Ba х ≥ 0.05. On the other hand, Obukuro et al [27] demonstrated the production of high-density ceramics (more than 95%) of La1-xBaxYbO3-δ (x = 0.02-0.1) after multistage synthesis and long-term sintering (10 h) at 1700 °C, although the authors did not check the Ba losses.…”

Tailoring Phase Fraction Induced Saturation Polarization Delay for High-Performance BaTiO3-Based Relaxed Ferroelectric Capacitors

“…46 Additionally, as the temperature increased, the Raman peaks gradually shift toward lower frequencies and a decrease in intensity, indicating a gradual decrease in the polarizability of the perovskite crystal cell. 47,48 However, over a very wide temperature range of 25 to 300 °C, the structural is almost unchanged, indicating excellent structural stability. Similarly, the 0.85BBNT-0.15BLTT ceramic also exhibits excellent frequency stability (W rec ∼ 3.6 J cm −3 ± 5% and η ∼ 87% ± 5%, from 1 to 200 Hz) and fatigue characteristics (W rec ∼ 3.6 J cm −3 ± 5% and η ∼ 87% ± 5%, over 10 4 cycles) (Figure The underdamped and overdamped behaviors of the 0.85BBNT-0.15BLTT ceramic are tested to evaluate charging/discharging performances.…”

Determination of Oxide Ion Conductivity in Ba-Doped LaYbO3 Proton-Conducting Perovskites via an Oxygen Isotope Exchange Method

“…The alkaline-earth-doped LaYbO 3 perovskites are considered as one of the candidates for CO 2 -tolerant proton-conducting electrolytes. − They possess relatively high proton conductivity with a high transport number of protons. ,, However, oxide ion conductivity in LaYbO 3 -based proton conductors is not quantified. The difficulty in determining the minor carrier conductivity always lies in the detection of smaller partial conductivity hidden in the major carriers.…”