A high temperature study on thermodynamic, thermal expansion and electrical properties of BaCe0.4Zr0.4Y0.2O3−δ proton conductor

Basbus, Juan Felipe; Arce, Mauricio D.; Prado, F.; Caneiro, A.; Mogni, L.

doi:10.1016/j.jpowsour.2016.08.083

Cited by 25 publications

(42 citation statements)

References 37 publications

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“…The high-frequency arc corresponds to the total BCZY impedance due to the overlap between bulk and grain boundary conductivity contributions. 13 The conductivity σ was obtained from the real axis interception of the high frequency arc (see σ −1 in Figure 1a), normalized by geometry and then corrected for the sample porosity (∼22%) according to our previous work. 13 So, for instance, at 400°C in wet synthetic air, BCZY displayed a high frequency arc with σ ≈ 0.002 S cm −1 , a relaxation frequency f max = 100 kHz, and capacitance C = 8 nFcm −1 .…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Revisiting the Crystal Structure of BaCe_0.4Zr_0.4Y_0.2O_3−δ Proton Conducting Perovskite and Its Correlation with Transport Properties

Basbus

Arce

Napolitano

et al. 2020

ACS Appl. Energy Mater.

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Oxides with proton conductivity have a great potential for applications in environmental energy technology. Despite the Ba-Ce 0.4 Zr 0.4 Y 0.2 O 3−δ (BCZY) perovskites being well-known proton conductors, it is a challenge to determine the optimal operating temperature range where the energy applications benefit most from this unique property. The protonic transport properties strongly depend on crystal structure and local distortions in the participating cation coordination sphere, according to related temperatures and gas feed. The transport and crystallographic properties of BCZY were simultaneously studied by impedance spectroscopy (IS) and synchrotron X-ray diffraction (S-XRD). A strong correlation between conductivity and the lattice parameter, corresponding in principle to a cubic symmetry, was observed, mainly between 400 and 700°C. The protonic conductivity range was analyzed by the H/D isotopic effect on the impedance spectra, which helped to identify protonic conduction as the governing transport mechanism below 600°C, while the transport via oxygen vacancies dominates above this temperature. In order to assess the real crystallographic structure, the simultaneous refinement of laboratory XRD and neutron diffraction (ND) patterns was performed. According to this, BCZY changes from rhombohedral symmetry below 400°C to cubic at 600°C in a second-order phase transition. Complementary quasielastic neutron scattering (QENS) enables us to determine a protonic jump length of 3.1 Å, which matches the O−O distances in the octahedral oxygen coordination sphere around the cations. These results support the protonic self-diffusion through proton hopping between intraoctahedral O sites as the main transport mechanism up to 600°C.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Revisiting the Crystal Structure of BaCe_0.4Zr_0.4Y_0.2O_3−δ Proton Conducting Perovskite and Its Correlation with Transport Properties

Basbus

Arce

Napolitano

et al. 2020

ACS Appl. Energy Mater.

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“…The density of fresh dense pellet of BCZP was measured by Archimedes method through hydrostatic weighing using the same electrobalance and diethyl phthalate as the immersion uid [30,31]. CO 2 tolerance must be evaluated through accelerated ageing tests due to Ba basicity and some gas impurities could affect the performance of the material under operating conditions.…”

Section: Methodsmentioning

confidence: 99%

“…Previous results demonstrated that the loss or incorporation of interstitial protons into the crystal structure cause distortions of lattice parameters and ionic conductivity [31]. BCZP was studied by HT-XRD under dry synthetic air to determine if such distortions are present in this compound.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Characterization of BaCe0.4Zr0.4Pr0.2O3−δ Mixed Conductor Perovskite

Basbus

Arce

Prado

et al. 2020

Preprint

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Abstract Compounds based on barium cerates and zirconates Ba(Ce,Zr)O3−δ are oxides able to transport protons through their crystal lattice by proton hopping between oxygen sites. This feature makes them potential candidates as hydrogen sensors, membranes for hydrogen purification and isotopic exchange, and electrolyte for Proton Conducting Solid Oxide Fuel Cell (PC-SOFC) and Solid Oxide Electrolyzer Cells (PC-SOEC). Pr-doping on these family compounds decreases sintering temperature and introduces electronic conductivity. This work presents a systematic study of the high temperature properties of the BaCe0.4Zr0.4Pr0.2O3−δ (BCZP) perovskite in view of its potential use for these applications. At room temperature, BCZP presents rhombohedral structure, which transforms reversibly to cubic at 550 °C in dry air. Electrochemical measurements under dry air, wet air with water vapor (~ 2% H2O) and heavy water vapor (~ 2% D2O) were employed to describe bulk ionic and electronic transport above 200 °C. The total conductivity data exhibit behavior changes between 400 and 600 °C which could be associated to a crystal structure transition. Below 600 ºC BCZP presents low total conductivity, which limits its applications as single phase cathode material for electrochemical applications. However, the material has good thermomechanical compatibility with electrolytes (~ 11 × 10− 6 K− 1) and high CO2 tolerance (T > 900 ºC). These properties suggest that this compound could be used as oxide support for composite or impregnated electrodes, buffer layer to improve the performance of another cathode material or gas separation co-ionic membranes.

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“…BaZr-or/and BaCe-based oxides. BaCe-and BaZr-based oxides have structures that allow transporting protons through their crystal lattice, which makes them attractive protonic conductor electrolytes [92]. While BaCeO 3 -based compounds present high conductivity and low chemical stability, BaZrO 3based ones exhibit the exact opposite [93,94].…”

Section: Protonic Conductorsmentioning

confidence: 99%

“…Oxides containing both Ce and Zr are also present in literature. Basbus et al [92] reported a study on BaCe 0.4 Zr 0.4 Y 0.2 O 3-d (BCZY) which was synthesized by a solid state reaction with amounts of BaCO 3 , CeO 2 , ZrO 2 and Y 2 O 3 . A crystal structure with cubic symmetry was observed.…”

Section: Protonic Conductorsmentioning

confidence: 99%

Novel materials for solid oxide fuel cell technologies: A literature review

Silva

Souza

2017

International Journal of Hydrogen Energy

331

110

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This study aims to review novel materials for solid oxide fuel cell (SOFC) applications covered in literature. Thence, it was found that current SOFC operating conditions lead to issues, such as carbon surface deposition, sulfur poisoning and quick component degradation at high temperatures, which make it unsuitable for a few applications. Therefore, many researches are focused on cell performance enhancement through replacing the materials being used in order to improve properties and/or reduce operating temperatures. Most modifications in the anode aim to avoid some issues concerning conventionally used Ni-based materials, such as carbon deposition and sulfur poisoning, besides enhancing catalytic activity, once this component is directly exposed to the fuel. It was also found literature about the cathode with the aim of developing a material with enhanced properties in a wider temperature range, which has been compared to the currently used one: LSM perovskite (La 1-x Sr x MnO 3). Novel electrolyte materials can have ionic or protonic conductivity, thus performance degradation must be avoided at several operating conditions. In order to enhance its electrochemical performance, different materials for electrodes (cathode and anode) and electrolytes have been assessed herein.

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A high temperature study on thermodynamic, thermal expansion and electrical properties of BaCe0.4Zr0.4Y0.2O3−δ proton conductor

Cited by 25 publications

References 37 publications

Revisiting the Crystal Structure of BaCe_0.4Zr_0.4Y_0.2O_3−δ Proton Conducting Perovskite and Its Correlation with Transport Properties

Revisiting the Crystal Structure of BaCe_0.4Zr_0.4Y_0.2O_3−δ Proton Conducting Perovskite and Its Correlation with Transport Properties

Synthesis and Characterization of BaCe0.4Zr0.4Pr0.2O3−δ Mixed Conductor Perovskite

Novel materials for solid oxide fuel cell technologies: A literature review

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A high temperature study on thermodynamic, thermal expansion and electrical properties of BaCe0.4Zr0.4Y0.2O3−δ proton conductor

Cited by 25 publications

References 37 publications

Revisiting the Crystal Structure of BaCe0.4Zr0.4Y0.2O3−δ Proton Conducting Perovskite and Its Correlation with Transport Properties

Revisiting the Crystal Structure of BaCe0.4Zr0.4Y0.2O3−δ Proton Conducting Perovskite and Its Correlation with Transport Properties

Synthesis and Characterization of BaCe0.4Zr0.4Pr0.2O3−δ Mixed Conductor Perovskite

Novel materials for solid oxide fuel cell technologies: A literature review

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Revisiting the Crystal Structure of BaCe_0.4Zr_0.4Y_0.2O_3−δ Proton Conducting Perovskite and Its Correlation with Transport Properties

Revisiting the Crystal Structure of BaCe_0.4Zr_0.4Y_0.2O_3−δ Proton Conducting Perovskite and Its Correlation with Transport Properties