Ruddlesden-Popper Lnn+1NinO3n+1 nickelates: structure and properties

Greenblatt, Martha

doi:10.1016/s1359-0286(97)80062-9

Cited by 123 publications

(91 citation statements)

References 60 publications

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“…Starting materials including Pr(NO 3 ) 3 , Nd(NO 3 ) 3 , and Ni(NO 3 ) 2 (99.9%, Alfa Aesar, Haverhill, MA) were standardized using thermogravimetric analysis and used in a glycine nitrate combustion process. The synthesized powders were calcined in air with 3…”

Section: Methodsmentioning

confidence: 99%

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Activity and Stability of (Pr_1-xNd_x)₂NiO₄as Cathodes for Solid Oxide Fuel Cells: Part V. In Situ Studies of Phase Evolution

Dogdibegovic

Alabri

Wright

et al. 2017

J. Electrochem. Soc.

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This study is to complement an early report (the manuscript is attached for review purpose) on the role of interlayer on activity and performance stability in praseodymium nickelates. The aforementioned report showed a remarkable 48% increase in power density while switching from common GDC interlayer to a new interlayer chemistry (PGCO). Furthermore, a stable long-term performance was linked with suppressed reaction between the cathode and PGCO interlayer. In this article, we report in situ studies of the phase evolution. The high energy XRD studies at a synchrotron source showed fully suppressed phase transition in praseodymium nickelates with PGCO interlayer, while the electrodes on the GDC interlayer undergo substantial phase transformation. Furthermore, in operando and post-test XRD analyses shown fully suppressed structural changes in electrodes operated in full cells at 750 • C and 0.80 V for 500 hours. SEM-EDS analysis showed that the formation of PrO x at the cathode-interlayer interface may play a role in a decrease of mechanical integrity of the interfaces, due to thermal expansion mismatch, leading to a local stress between the two phases. Consequently, phase evolution at a narrow interface may propagate toward the electrode bulk, leading to structural changes and performance degradation. The interest for Pr 2 NiO 4 (PNO) electrode stems from the necessity to develop active and stable oxygen electrodes 1-6 for solid oxide fuel cells (SOFCs).7-9 PNO is known for its highly active nature, 7,8,10 originated from its superior oxygen ion diffusion, surface exchange coeffocient 2,7,9-11 and structural flexibility over a wide temperature region (from 500 to 900• C). 3,12 PNO electrode, however, does undergo the structural evolution to form a higher order phase (Pr 3 Ni 2 O 7 ) and Pr 6 O 11 (PrO x ). 8 The structural change has been a major concern because it possibly links with the performance degradation over a long-term operation.7,8 Conventional X-ray diffraction (XRD) has been extensively used to investigate the structural evolution in nickelates in the form of powders or planar electrodes. 8,10 This method has two major limitations due to its low flux and low resolution: (1) it might overlook the presence of additional phases in the system, which is especially true for praseodymium nickelates where XRD diffraction patterns of higher order phase(s) (e.x. Pr 3 Ni 2 O 7 ) may overlap with the parent PNO phase, making quantification challenging; 8 and (2) the quantification of phase evolution in electrochemically operated PNO electrode may show major structural change with almost 100% of the parent phase transition from the conventional XRD analysis, while the transmission electron microscopy (TEM) studies clearly show the regions of preserved PNO phase. 7On the other hand, the high energy and high flux XRD (obtained at a synchrotron source) allows us to detect and resolve the presence of secondary phase(s), and in combination with high resolution capability provides the most accurate measurement regardin...

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Section: Methodsmentioning

confidence: 99%

“…3,12 PNO electrode, however, does undergo the structural evolution to form a higher order phase (Pr 3 Ni 2 O 7 ) and Pr 6 O 11 (PrO x ). 8 The structural change has been a major concern because it possibly links with the performance degradation over a long-term operation.…”

mentioning

confidence: 99%

Activity and Stability of (Pr_1-xNd_x)₂NiO₄as Cathodes for Solid Oxide Fuel Cells: Part V. In Situ Studies of Phase Evolution

Dogdibegovic

Alabri

Wright

et al. 2017

J. Electrochem. Soc.

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“…2+1 . The discovery of the RuddlesdenPopper phases Ln n−1 (NiO 2 ) n Ln 2 O 2 (Ln=La, Pr, Nd; n=1, 2, 3) with n cuprate-like NiO 2 layers reinvigorated the interest in nickelates [2][3][4][5][6][7][8][9] . Within this series, the trilayer La 4 Ni 3 O 8 (La438) and bilayer La 3 Ni 2 O 6 (La326) compounds are ionic but highly unconventional insulators 7,8 .…”

mentioning

confidence: 99%

Charge ordering inNi1+/Ni2+nickelates:La4
Botana
¹
,
Pardo
²
,
Pickett
³

et al. 2016
Phys. Rev. B
55
4
46
1
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Ab initio calculations allow us to establish a close connection between the Ruddlesden-Popper layered nickelates and cuprates not only in terms of filling of d-levels (close to d 9 ) but also because they show Ni 1+ (S=1/2)/Ni 2+ (S=0) stripe ordering. The insulating charge ordered ground state is obtained from a combination of structural distortions and magnetic order. The Ni 2+ ions are in a low-spin configuration (S=0) yielding an antiferromagnetic arrangement of Ni 1+ S=1/2 ions like the long-sought spin-1/2 antiferromagnetic insulator analog of the cuprate parent materials. The analogy extends further with the main contribution to the bands near the Fermi energy coming from hybridized Ni-d x 2 −y 2 and O-p states. 7,8 . As the n=3 and n=2 members of the series, they have a formal Ni valence of +1.33 and +1.5, respectively, which being noninteger should correspond to metallic behavior, yet both are insulating. The NiO 2 slabs are separated by fluorite structure LaO blocking layers that make the inter-trilayer/bilayer coupling very weak. The lack of apical oxygen ions reduces the interplane separation substantially and opens a large crystal field splitting for the e g states with the d x 2 −y 2 state lying higher in energy than d z 2 . The d z 2 orbitals hybridize along the z direction giving rise to n molecular subbands. Depending on the relative magnitude of the crystal field splitting and Hund's rule coupling, the ground state can be either high spin (HS) and insulating or low spin (LS) and metallic as depicted in Fig.

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“…The latter (ABO 3 ) n /(AO) (also denoted as A n þ 1 B n O 3n þ 1 ) RP structure has n ABO 3 perovskite blocks stacked along the [001] direction with an extra sheet of AO rocksalt layers interleaved every n perovskite layers. This geometry disconnects the BO 6 octahedra along one direction and imposes severe constraints on the nearest-neighbour interactions 16 , promoting anisotropy in the structure-derived electronic, transport and magnetic properties, which contrasts sharply with the 3D perovskite analogues [17][18][19][20] . Indeed, the RP structure dimensionality 21,22 , that is, systematic stacking of the n layers along [001] direction, has recently been exploited 23 in combination with epitaxial strain to achieve highly tunable low-loss dielectrics.…”

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confidence: 99%

Massive band gap variation in layered oxides through cation ordering

Balachandran

Rondinelli

2015

Nat Commun

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The electronic band gap is a fundamental material parameter requiring control for light harvesting, conversion and transport technologies, including photovoltaics, lasers and sensors. Although traditional methods to tune band gaps rely on chemical alloying, quantum size effects, lattice mismatch or superlattice formation, the spectral variation is often limited to o1 eV, unless marked changes to composition or structure occur. Here we report large band gap changes of up to 200% or B2 eV without modifying chemical composition or use of epitaxial strain in the LaSrAlO 4 Ruddlesden-Popper oxide. First-principles calculations show that ordering electrically charged [LaO] 1 þ and neutral [SrO] 0 monoxide planes imposes internal electric fields in the layered oxides. These fields drive local atomic displacements and bond distortions that control the energy levels at the valence and conduction band edges, providing a path towards electronic structure engineering in complex oxides.

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Ruddlesden-Popper Lnn+1NinO3n+1 nickelates: structure and properties

Cited by 123 publications

References 60 publications

Activity and Stability of (Pr_1-xNd_x)₂NiO₄as Cathodes for Solid Oxide Fuel Cells: Part V. In Situ Studies of Phase Evolution

Activity and Stability of (Pr_1-xNd_x)₂NiO₄as Cathodes for Solid Oxide Fuel Cells: Part V. In Situ Studies of Phase Evolution

Charge ordering inNi1+/Ni2+nickelates:La4
Botana
¹
,
Pardo
²
,
Pickett
³

et al. 2016
Phys. Rev. B
55
4
46
1
View full text Add to dashboard Cite

Massive band gap variation in layered oxides through cation ordering

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Ruddlesden-Popper Lnn+1NinO3n+1 nickelates: structure and properties

Cited by 123 publications

References 60 publications

Activity and Stability of (Pr1-xNdx)2NiO4as Cathodes for Solid Oxide Fuel Cells: Part V. In Situ Studies of Phase Evolution

Activity and Stability of (Pr1-xNdx)2NiO4as Cathodes for Solid Oxide Fuel Cells: Part V. In Situ Studies of Phase Evolution

Charge ordering inNi1+/Ni2+nickelates:La4Botana1, Pardo2, Pickett3 et al. 2016Phys. Rev. B554461View full textAdd to dashboardCite

Massive band gap variation in layered oxides through cation ordering

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Activity and Stability of (Pr_1-xNd_x)₂NiO₄as Cathodes for Solid Oxide Fuel Cells: Part V. In Situ Studies of Phase Evolution

Activity and Stability of (Pr_1-xNd_x)₂NiO₄as Cathodes for Solid Oxide Fuel Cells: Part V. In Situ Studies of Phase Evolution

Charge ordering inNi1+/Ni2+nickelates:La4
Botana
¹
,
Pardo
²
,
Pickett
³

et al. 2016
Phys. Rev. B
55
4
46
1
View full text Add to dashboard Cite