Preparation, characterization and electrical property of Mn-doped ceria-based oxides

Kang, Ch. Y.; Kusaba, Hajime; Yahiro, Hidenori; Sasaki, Kazunari; Teraoka, Yasutake

doi:10.1016/j.ssi.2006.04.016

Cited by 67 publications

(50 citation statements)

References 3 publications

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“…Journal of The Electrochemical Society, 165 (7) F533-F542 (2018) 52 to < 1 mol% for Mn 34 in ceria). Obviously, the amount of incorporated metal cations as well as their valence in sintered ceria depends strongly on the preparation method, sintering temperature and co-dopant concentrations 28,32,33 which underlines the importance of an investigation of charge carrier transport for materials with a standardized (commercial) ceria host matrix.…”

Section: F534mentioning

confidence: 99%

Assessment of the Effect of Transition Metal Oxide Addition on the Conductivity of Commercial Gd-Doped Ceria

Neuhaus¹,

Dolle²,

Wiemhöfer³

2018

J. Electrochem. Soc.

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The effect of addition of transition metal oxides on the charge transport of commercially available Gd-doped ceria (Ce 0.9 Gd 0.1 O 2-δ ) was assessed with special emphasis on the electronic partial conductivity. The samples were doped by adding 2, 4 or 6 cat% of CoO 3/4 or FeO 2/3 , or 2 mol% of the transition metal oxides V 2 O 5 , MnO 2 , and CuO, respectively. It was found that even small amounts of transition metal oxides severely change the partial electronic conductivity of ceria while the majority oxygen ion conductivity was only mildly affected: for high oxygen ion conductivity, Fe or Mn oxide addition as well as small amounts of Co oxide are beneficial, as especially the grain boundary conductivity is slightly increased. Addition of V or Cu oxide in contrast increases the minority charge carrier conductivity of electrons and thus enhances the mixed ionic-electronic conductivity. For Co oxide addition, an increasing electronic conductivity with decreasing oxygen partial pressure from 10 −8 to 10 −4 bar at temperatures below 600 • C indicates the changing redox state of Co from divalent at low oxygen partial pressures to trivalent under ambient oxygen partial pressure.

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Section: F534mentioning

confidence: 99%

Assessment of the Effect of Transition Metal Oxide Addition on the Conductivity of Commercial Gd-Doped Ceria

Neuhaus¹,

Dolle²,

Wiemhöfer³

2018

J. Electrochem. Soc.

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“…However, the need to produce such cells economically at low temperature remains an issue and has prompted studies into the use of dopants and nano-sized powders to reduce the 1200C traditionally required to densify CGO electrolytes [4,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Objectives and Experimentsmentioning

confidence: 99%

“…Due to it's high oxygen ion conductivity at intermediate (500-700C) temperature and potential use as a commercial solid oxide fuel cell (SOFC) electrolyte, many investigators [4,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]] have sought to densify Ce 0.9 Gd 0.1 O 1.95 (CGO) at low temperature using sintering aids. In Chapter 2, it was argued that a sintering aid's ability to promote densification by 1) increasing the grain boundary oxygen vacancy concentration (an effect commonly known as the undersized dopant effect) and/or 2) forming a liquid or intergranular phase was fundamentally a matter of a dopant's size and charge and could be summarized in terms of a Vegard's Slope quality factor.…”

Section: Introductionmentioning

confidence: 99%

Low Temperature Constrained Sintering of Cerium Gadolinium OxideFilms for Solid Oxide Fuel Cell Applications

Nicholas

2007

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Cerium gadolinium oxide (CGO) has been identified as an acceptable solid oxide fuel cell (SOFC) electrolyte at temperatures (500-700°C) where cheap, rigid, stainless steel interconnect substrates can be used. Unfortunately, both the high sintering temperature of pure CGO, >1200°C, and the fact that constraint during sintering often results in cracked, low density ceramic films, have complicated development of metal supported CGO SOFCs.The aim of this work was to find new sintering aids for Ce 0.9 Gd 0.1 O 1.95 , and to evaluate whether they could be used to produce dense, constrained Ce 0.9 Gd 0.1 O 1.95 films at temperatures below 1000°C. To find the optimal sintering aid, Ce 0.9 Gd 0.1 O 1.95 was doped with a variety of elements, of which lithium was found to be the most effective.Dilatometric studies indicated that by doping CGO with 3mol% lithium nitrate, it was possible to sinter pellets to a relative density of 98.5% at 800C-a full one hundred degrees below the previous low temperature sintering record for CGO. Further, it was also 2 found that a sintering aid's effectiveness could be explained in terms of its size, charge and high temperature mobility.A closer examination of lithium doped Ce 0.9 Gd 0.1 O 1.95 indicated that lithium affects sintering by producing a Li 2 O-Gd 2 O 3 -CeO 2 liquid at the CGO grain boundaries. Due to this liquid phase sintering, it was possible to produce dense, crack-free constrained films of CGO at the record low temperature of 950C using cheap, colloidal spray deposition processes. This is the first time dense constrained CGO films have been produced below 1000C and could help commercialise metal supported ceria based solid oxide fuel cells. Thesis Motivation, Background and Overview MotivationMore efficient technologies are needed if the world is to meet the doubling of energy demand that is projected to occur in the next 25 years. Given the large natural reserves of hydrocarbons and the existing infrastructure, it seems likely that traditional fuels (such as gasoline and liquefied natural gas) will retain their importance, even as alternatives such as bio-fuels enter the marketplace. Thankfully, the efficiency increases possible by electrochemically reacting these fuels inside a fuel cell instead of combusting them are considerable, making it possible to lower the environmental costs associated with their continued use. For instance, solid oxide fuel cells (SOFCs) are expected to achieve first law efficiencies of 80-85% when used with cogeneration [1]; whereas, the mostefficient combustion systems used today only achieve efficiencies of 50% [2]. Fuel Cell BasicsA fuel cell utilizing an oxygen-conducting electrolyte, such as a solid oxide fuel cell, is schematically illustrated in Figure 1. Here an oxidant (usually atmospheric O 2 ) is added to the cathode chamber of the fuel cell where it takes on electrons and destroys oxygen ion vacancies within the electrolyte by filling them with oxygen. At the same time, fuel, such as H 2 , is added to the anode chamber where i...

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“…Mainly Gd 2 O 3 [7,10,11], but in some cases also other oxides [1], were used as main dopants to fix the oxygen vacancy concentration of the material. The solubility limit of Mn in pure ceria has been found to be in the range between 5-10 mol % [7,8,12], or <1 mol % in another study [13]. Also, the solubility was found to be lower in combination with Gd as a co-dopant (≤5 mol %) [12].…”

Section: Introductionmentioning

confidence: 89%

“…The solubility limit of Mn in pure ceria has been found to be in the range between 5-10 mol % [7,8,12], or <1 mol % in another study [13]. Also, the solubility was found to be lower in combination with Gd as a co-dopant (≤5 mol %) [12].…”

Section: Introductionmentioning

confidence: 89%

Effect of MnO2 Concentration on the Conductivity of Ce0.9Gd0.1MnxO2−δ

et al. 2018

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Samples with the composition Ce 0.9 Gd 0.1 Mn x O 2−δ with x = 0.01, 0.02, and 0.05 Mn-addition were prepared by mixed oxide route from Ce 0.9 Gd 0.1 O 2−δ and MnO 2 and sintered at 1300 • C. The electronic conductivity was measured using a modified Hebb-Wagner technique, the electrical conductivity was investigated by impedance spectroscopy, and oxygen permeation was measured for the sample with x = 0.05. An increase of the electronic partial conductivity with increasing Mn addition was observed, which can be attributed to an additional Mn 3d-related state between the top of the valence band and the bottom of the Ce 4f band. The grain boundary conductivity was found to be suppressed for low Mn contents, but enhanced for the sample with x = 0.05.

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Preparation, characterization and electrical property of Mn-doped ceria-based oxides

Cited by 67 publications

References 3 publications

Assessment of the Effect of Transition Metal Oxide Addition on the Conductivity of Commercial Gd-Doped Ceria

Assessment of the Effect of Transition Metal Oxide Addition on the Conductivity of Commercial Gd-Doped Ceria

Low Temperature Constrained Sintering of Cerium Gadolinium OxideFilms for Solid Oxide Fuel Cell Applications

Effect of MnO2 Concentration on the Conductivity of Ce0.9Gd0.1MnxO2−δ

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