LaMnO3 air cathodes containing ZrO2 electrolyte for high temperature solid oxide fuel cells

Kenjo, T.; Nishiya, Manami

doi:10.1016/0167-2738(92)90161-h

Cited by 246 publications

(127 citation statements)

References 5 publications

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“…25 As A-site deficient composition is used in the present study, the formation of lanthanum zirconate will be depressed as compared to the stoichiometrical LSM. 46 After cathodic polarization treatment for 3 h, the sharp edge of the crater rings disappears and rings are flattened and grow outward. The growth and widening of the convex rings increases with the increase of the cathodic polarization current densities (see Fig.…”

Section: Resultsmentioning

confidence: 99%

Thermally and Electrochemically Induced Electrode/Electrolyte Interfaces in Solid Oxide Fuel Cells: An AFM and EIS Study

Jiang

2015

J. Electrochem. Soc.

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In high temperature solid oxide fuel cells (SOFCs), electrode/electrolyte interfaces play a critical role in the electrocatalytic activity and durability of the cells. In this study, thermally and electrochemically induced electrode/electrolyte interfaces were investigated on pre-sintered and in situ assembled (La 0.8 Sr 0.2 ) 0.90 MnO 3 (LSM) and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) electrodes on Y 2 O 3 -ZrO 2 (YSZ) and Gd 0.2 Ce 0.8 O 2 (GDC) electrolytes, using atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The results indicate that thermally induced interface is characterized by convex contact rings with depth of 100-400 nm and diameter in agreement with the particle size of pre-sintered LSM and LSCF electrodes, while the electrochemically induced interfaces under cathodic polarization conditions on in situ assembled electrodes are characterized by particle-shaped contact marks or clusters (50-100 nm in diameter). The number and distribution of contact clusters depend on the cathodic current density as well as the electrode and electrolyte materials. The contact clusters on the in situ assembled LSCF/GDC interface are substantially smaller than that on the in situ assembled LSM/GDC interface likely due to the high mixed ionic and electronic conductivities of LSCF materials. The results show that the electrochemically induced interface is most likely resulting from the incorporation of oxygen species and cation interdiffusion under cathodic polarization conditions. However, the electrocatalytic activity of electrochemically induced electrode/electrolyte interfaces is comparable to the thermally induced interfaces for the O 2 reduction reaction under SOFC operation conditions. © The Author Solid oxide fuel cell (SOFC) is one of the most efficient technologies for the conversion of chemical energy of fuels such as hydrogen and natural gas directly into electrical power. It employs a solid oxide electrolyte such as yttria-stabilized zirconia (YSZ) that serves as an ionic conductor in the temperature range between 600• C to 1000• C. The electrolyte separates the cathode from the anode and conducts oxygen ions from the cathode to the anode where they react electrochemically with the fuel. Electrons are then released to an external circuit, which provides a useful source of electrical power. The electrochemical reactions such as O 2 reduction at the cathode and H 2 oxidation at the anodes occur at the electrode/electrolyte interface regions.1-3 Thus, in SOFCs, electrode/electrolyte interfaces play a vital role in the mechanism and kinetics of the electrochemical reactions and in the fundamental understanding of the relationship between the electrochemical processes and microstructure.4-10 The cell performance and durability also depend strongly on the microstructural change at the interface under SOFC operation conditions. 11,12Lanthanum strontium manganite (LSM) is one of the most common cathode materials for SOFCs because of high electrical conductivity, good thermal and chem...

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Section: Resultsmentioning

confidence: 99%

Thermally and Electrochemically Induced Electrode/Electrolyte Interfaces in Solid Oxide Fuel Cells: An AFM and EIS Study

Jiang

2015

J. Electrochem. Soc.

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“…Alguns pesquisadores observaram que a resistência de polarização do material diminui com o aumento da proporção ZEI/ MLS (em peso) [8]. Adições de ZEI de 40%, em peso, acarretam melhoras no desempenho do catodo devido a boa adesão compósito/eletrólito e a um aumento na concentração dos TPB nesta região [1].…”

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A importância da camada funcional em meia células catódicas para pilhas PaCOS

Belardi¹,

Domingues²,

Matencio³

et al. 2008

Matéria (Rio J.)

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RESUMOO grande desafio para se melhorar o desenvolvimento de pilhas a combustível de óxido sólido (PACOS) é diminuir as resistências de polarização ôhmica e de polarização de concentração, sobretudo no catodo. Uma alternativa efetiva é a introdução de uma camada catódica funcional entre o eletrólito e o catodo convencional. Esta camada funcional é um compósito constituído pelos materiais de eletrólito e catodo que neste caso são a zircônia estabilizada com ítria (ZEI) e a manganita de lantânio e estrôncio (MSL). Esta camada melhora o contato entre o catodo e o eletrólito diminuindo a resistência ôhmica de polarização de concentração devido ao aumento do número de pontos de contato triplo (PCT) no volume do material.Neste trabalho, duas meias células foram preparadas: a primeira é constituída por um filme catódico funcional (50% p/p) e a camada coletora de corrente depositados sobre uma pastilha de ZEI. A segunda meia célula é composta apenas pela camada catódica de MSL também depositada sobre a pastilha de ZEI.O estudo elétrico foi realizado por espectroscopia de impedância na faixa de temperatura entre 700 e 900 °C. As resistências das amostras diminuíram com o aumento da temperatura e, foi observado que a meia célula que possuía o catodo funcional apresentou menores resistências elétricas. Após tratamento térmico a 750°C por 3 dias foi verificado que a amostra sem a camada funcional apresentou um semicírculo adicional no diagrama de impedância caracterizado como uma resistência devida a baixa aderência eletrólito/catodo. Este fenômeno foi confirmado por imagens de microscopia eletrônica de varredura (MEV). Palavras-chaves: MLS, Espectroscopia de impedância, catodo funcional. The importance of the functional layer in SOFC half cathodic cell ABSTRACTThe greatest challenge to improve SOCF (Solid Oxide Fuel Cell) development is to decrease polarization and ohmic concentration resistances mainly for the cathode. One effective alternative is the introduction of a functional cathode layer between the electrolyte and the conventional cathode. This functional cathode layer is a composite constituted by the electrolyte and cathode materials, in this case, yttria stabilized zirconia (YSZ) and lanthanum doped strontium (LSM). This layer improves the contact between the cathode and the electrolyte decreasing the ohmic concentration polarization due to the increasing of triple contact points (TPB) in the bulk concentration.In this work, two half cells were prepared: the first one is constituted by a functional cathode film (50% in weight), and a collecting current layer (LSM) both deposited on a YSZ pellet. The second half cell is composed by a LSM cathode layer deposited on the YSZ Tosoh pellet.The electric study has been realized by Impedance Spectroscopy varying the temperature from 700 to 900 ºC. The two half cells resistance decreased with increasing the temperature, and it has noted that the half cell with the functional cathode layer presented the lowest resistance. After annealing at 750 °C for 3 days, the sample wi...

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“…In general, two phase composite cathodes are introduced to improve electrode performance. 1),2) The two phase composite cathode is composed by electrolyte material such as yttria stabilized zirconia (YSZ) or scandia doped zirconia (ScSZ) and electrocatalyst such as strontium doped lanthanum manganite (LSM). It has a well-controlled structure with mutually intertwined ionic and electronic conduction network paths in an attempt to three-dimensionally extend active sites for oxygen reduction.…”

Section: Introductionmentioning

confidence: 99%

The effects of preparation conditions on mechanically fabricated composite particles for solid oxide fuel cells

Hobara

Abe

Naito

et al. 2011

J. Ceram. Soc. Japan

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The present paper discusses the effect of material charging in a mechano-chemical particle fabrication process for the production of LSM/ScSZ composite particle material developed for solid oxide fuel cells. The composite particle considered here has a structure where coarse electro-catalyst particles are coated with fine electrolyte particles so that they can be used as "pre-fabricated" electrode microstructure elements. The study reveals that the intended composite particle material can be the most successfully fabricated by repeatedly charging a small amount of fine ScSZ particles and that the electrochemical performance can be improved to a substantial degree when the particle fabrication process is carefully controlled.

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LaMnO3 air cathodes containing ZrO2 electrolyte for high temperature solid oxide fuel cells

Cited by 246 publications

References 5 publications

Thermally and Electrochemically Induced Electrode/Electrolyte Interfaces in Solid Oxide Fuel Cells: An AFM and EIS Study

Thermally and Electrochemically Induced Electrode/Electrolyte Interfaces in Solid Oxide Fuel Cells: An AFM and EIS Study

A importância da camada funcional em meia células catódicas para pilhas PaCOS

The effects of preparation conditions on mechanically fabricated composite particles for solid oxide fuel cells

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