Development of Monolithic YSZ Porous and Dense Layers through Multiple Slip Casting for Ceramic Fuel Cell Applications

“…26,27 The effectiveness of using this processed YSZ powder in improving the electrochemical performance of LSM 28 and LSBT (La 0.4 Sr 0.5 Ba 0.1 TiO 3 ) 29,30 infiltrated cells has been shown recently. In addition, Batista and Muccillo 31,32 found that addition of a small amount of NiO to 8YSZ improves the sinterability of the electrolyte without affecting its overall conductivity.…”

Section: Resultsmentioning

confidence: 98%

Development of Redox Resistant Fully Infiltrated Tubular SOFCs

Hanifi

Torabi

Chen

et al. 2014

J. Electrochem. Soc.

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The electrochemical performance of two infiltrated SOFCs (solid oxide fuel cells) and the redox cycling tolerance of such cells are presented. NiO-SDC (Sm 0.2 Ce 0.8 O 1.9 ) was infiltrated into a porous 8YSZ (8 mol% Y 2 O 3 ) support to form the anode of the infiltrated cells and LSM (La 0.80 Sr 0.20 MnO 3 ) or Nd-nickelate (Nd 2 NiO 4 ) was infiltrated into a thin porous YSZ layer to form the cathode. The power density of the Nd-nickelate infiltrated cell is higher than that of the LSM infiltrated cell suggesting it as a suitable cathode for intermediate temperature applications. The microstructure of these infiltrated solid oxide fuel cells shows a reasonable distribution of fine particles (50-100 nm) near the interface of electrodes and electrolyte and within the bulk electrodes. Despite having much lower Ni content than conventional anode supported cells, the infiltrated fuel cells exhibit a reasonable power density at low temperatures and an excellent robustness against redox cycling when air is used as the anode oxidant.Infiltration has been established as an effective method to produce state of the art high performance electrodes for ceramic fuel cells. Infiltration is usually carried out in order to improve the catalytic activity or enhance the ionic or electronic conductivity or both in SOFC electrodes. While the fine dispersed infiltrates introduce catalytic activity, the connected particles with high surface area form the conduction pathways and can boost the fuel cell performance thereby enabling a reduced operating temperature, improving cell stability and reliability. 1,2 The more favorable particle size and surface activity of the infiltrates are a result of a comparatively low heat-treatment temperature needed to decompose the nitrates and form the final phase versus the conventional sintering temperatures required for composite electrodes.A fuel cell may undergo several redox cycles during its lifetime due to possible air or fuel leakage, accidental interruption in the fuel supply or even high fuel utilization which can lead to complete cell failure. Extensive research has been carried out to date to study the effect of redox cycling on the performance and microstructure of Ni based anodes. 3-5 If the fuel supply to the anode is cut off, air can oxidize the Ni metal into NiO which, in theory, is accompanied by 69.2% volume expansion while NiO reduction causes a 40.9% contraction. 6 Due to an expansion mismatch between the cell components, stresses are built up near the interface of electrode and electrolyte during redox cycling. Heo et al. 7 reported that redox cycling led to a decrease in electrical conductivity, cracking of the YSZ network, reduction of OCV and loss of power density in anode supported tubular SOFCs. They correlated the performance degradation to cracks formed within the cell and delamination at the electrode/electrolyte interface which causes contact loss between the electrolyte and the anode functional layer.An important benefit of Ni infiltration is enhancement of the redox...

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“…Infiltration of porous YSZ substrates with anode or cathode materials can provide electrodes with superior electrochemical performance compared with traditionally prepared electrodes [75]. The authors developed different types of porous YSZ microstructures for infiltration by calcination of Tosoh YSZ (a commonly used YSZ powder for SOFC fabrication) at 1300 • C-1500 • C and milling the coarsened powder in an aqueous suspension for 72 h [76][77][78][79][80]. Calcination is an essential method for development of a porous substrate since asreceived YSZ powder normally has fine particles (250 nm), a high surface area (12-13 m 2 g −1 ) and thus high sinterability.…”

Section: Calcination and Milling Of Yszmentioning

confidence: 99%

“…Calcination and subsequent milling lead to the formation of particles with larger size (500-750 nm) and a lower surface area (3-5 m 2 g −1 ). The particle size correlates with the calcination temperature (figure 6) [79]. The reduced surface area of YSZ leads to generation of a porous structure following sintering at 1350 • C-1400 • C which contains interconnected pores (∼20%-25%) even without incorporation of any pore-formers.…”

Section: Calcination and Milling Of Yszmentioning

confidence: 99%

Microstructure and long-term stability of Ni–YSZ anode supported fuel cells: a review

et al. 2022

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Nickel-yttria stabilized zirconia (Ni-YSZ) cermet is the most commonly used anode in solid oxide fuel cells (SOFCs). The current article provides an insight into parameters which affect cell performance and stability by reviewing and discussing the related publications in this field. Understanding the parameters which affect the microstructure of Ni-YSZ such as grain size and ratio of Ni to YSZ, volume fraction of porosity, pore size and its distribution, tortuosity factor, characteristic pathway diameter and density of triple phase boundaries (TPBs) is the key to design a fuel cell which shows high electrochemical performance. Lack of stability has been the main barrier to commercialization of SOFC technology. Parameters influencing the degradation of Ni-YSZ supported SOFCs such as Ni migration inside the anode during prolonged operation are discussed. The longest Ni-supported SOFC tests reported so far are examined and the crucial role of chromium poisoning due to interconnects (ICs), stack design and operating conditions in degradation of SOFCs is highlighted. The importance of calcination and milling of YSZ on development of porous structures suitable for Ni infiltration is explained and several methods to improve the electrochemical performance and stability of Ni-YSZ anode supported SOFCs are suggested.

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Development of Monolithic YSZ Porous and Dense Layers through Multiple Slip Casting for Ceramic Fuel Cell Applications

Cited by 21 publications

References 30 publications

Porous YSZ impregnated with La0.4Sr0.5Ba0.1TiO3 as a possible composite anode for SOFCs fueled with sour feeds

Porous YSZ impregnated with La0.4Sr0.5Ba0.1TiO3 as a possible composite anode for SOFCs fueled with sour feeds

Development of Redox Resistant Fully Infiltrated Tubular SOFCs

Microstructure and long-term stability of Ni–YSZ anode supported fuel cells: a review

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