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Yang, Huai; Xia, Yang; Shi, Youguo; Tian, Hongkun; Xiao, Ru; Liu, X.; Liu, Y. L.; Li, J. Q.

doi:10.1103/physrevb.74.094301

Cited by 30 publications

(7 citation statements)

References 30 publications

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“…At x = 1/2, Na ions arrange themselves in a 2 × √ 3 zigzag pattern, the same as P2-Na 1/2 CoO 2 . This arrangement agrees well with the experimental results [10,28]. With this ordering pattern, a similar charge ordering picture in CoO 2 can be expected as that observed in P2-Na x CoO 2 .…”

Section: Na Ordering In P-type Na X Coosupporting

confidence: 91%

Ground-state phase diagram of Na_xCoO₂: correlation of Na ordering with CoO₂stacking sequences

Wang¹,

Ding²,

Ni³

2008

J. Phys.: Condens. Matter

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We have proposed a Hamiltonian that takes into account both Na-Na interactions and coupling between Na ions and CoO(2) layers. By a combination of the Monte Carlo and first-principles approaches, all the possible stacking sequences of CoO(2) layers together with the Na ordering have been obtained. In particular, an infinite series of ground states of Na ordering has been predicted in P3-Na(x)CoO(2). We have obtained the ground-state phase diagram with the variation of Na concentration, which explains well the complex variation of the CoO(2) stacking sequences. Our calculations show that the ordering of Na ions to minimize the Coulomb interaction is the main cause of the variation of the CoO(2) stacking sequences.

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Section: Na Ordering In P-type Na X Coosupporting

confidence: 91%

Ground-state phase diagram of Na_xCoO₂: correlation of Na ordering with CoO₂stacking sequences

Wang¹,

Ding²,

Ni³

2008

J. Phys.: Condens. Matter

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“…The bands with Raman shifts between 200 cm −1 and 700 cm −1 can be assigned to A 1g , E 1g and E 2g modes of the P2-type material (Iliev et al, 2004). To the best of our knowledge, so far the band assignments for P2-type sodium transition metal layered oxides in literature are not consistent (Iliev et al, 2004;Lemmens et al, 2004;Qu et al, 2006;Yang et al, 2006;Singh et al, 2015;Wang et al, 2016). From the obtained Raman spectra, no change of the local crystal structure is evident over the course of the model storage experiment.…”

Section: Effect Of Storagementioning

confidence: 85%

Layered P2-NaxMn3/4Ni1/4O2 Cathode Materials For Sodium-Ion Batteries: Synthesis, Electrochemistry and Influence of Ambient Storage

et al. 2022

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Sodium-ion batteries promise efficient, affordable and sustainable electrical energy storage that avoids critical raw materials such as lithium, cobalt and copper. In this work, a manganese-based, cobalt-free, layered NaxMn3/4Ni1/4O2 cathode active material for sodium-ion batteries is developed. A synthesis phase diagram was developed by varying the sodium content x and the calcination temperature. The calcination process towards a phase pure P2-Na2/3Mn3/4Ni1/4O2 material was investigated in detail using in-situ XRD and TGA-DSC-MS. The resulting material was characterized with ICP-OES, XRD and SEM. A stacking fault model to account for anisotropic broadening of (10l) reflexes in XRD is presented and discussed with respect to the synthesis process. In electrochemical half-cells, P2-Na2/3Mn3/4Ni1/4O2 delivers an attractive initial specific discharge capacity beyond 200 mAh g−1, when cycled between 4.3 and 1.5 V. The structural transformation during cycling was studied using operando XRD to gain deeper insights into the reaction mechanism. The influence of storage under humid conditions on the crystal structure, particle surface and electrochemistry was investigated using model experiments. Due to the broad scope of this work, raw material questions, fundamental investigations and industrially relevant production processes are addressed.

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“…The two modes in this compound are reported to be predominantly Co-O stretching and O-Co-O bending motions, which are supported by Li isotope substitution experiments as well as a comparison to the isostructural compound NaCoO 2. In this compound, the E g and A 1g Raman modes are at 486 and 586 cm −1 , respectively [47]. Notice that by substituting sodium for lithium, the E g mode does not shift in frequency within experimental resolution.…”

Section: Ambient Pressurementioning

confidence: 69%

LiCrO2 Under Pressure: In-Situ Structural and Vibrational Studies

et al. 2018

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The high-pressure behaviour of LiCrO2, a compound isostructural to the battery compound LiCoO2, has been investigated by synchrotron-based angle-dispersive X-ray powder diffraction, Raman spectroscopy, and resistance measurements up to 41, 30, and 10 Gpa, respectively. The stability of the layered structured compound on a triangular lattice with R-3m space group is confirmed in all three measurements up to the highest pressure reached. The dependence of lattice parameters and unit-cell volume with pressure has been determined from the structural refinements of X-ray diffraction patterns that are used to extract the axial compressibilities and bulk modulus by means of Birch–Murnaghan equation-of-state fits. The pressure coefficients for the two Raman-active modes, A1g and Eg, and their mode-Grüneisen parameters are reported. The electrical resistance measurements indicate that pressure has little influence in the resistivity up to 10 GPa. The obtained results for the vibrational and structural properties of LiCrO2 under pressure are in line with the published results of the similar studies on the related compounds. Research work reported in this article contributes significantly to enhance the understanding on the structural and mechanical properties of LiCrO2 and related lithium compounds.

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Raman spectroscopy study ofα-,β-,γ−NaxCo

Cited by 30 publications

References 30 publications

Ground-state phase diagram of Na_xCoO₂: correlation of Na ordering with CoO₂stacking sequences

Ground-state phase diagram of Na_xCoO₂: correlation of Na ordering with CoO₂stacking sequences

Layered P2-NaxMn3/4Ni1/4O2 Cathode Materials For Sodium-Ion Batteries: Synthesis, Electrochemistry and Influence of Ambient Storage

LiCrO2 Under Pressure: In-Situ Structural and Vibrational Studies

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Raman spectroscopy study ofα-,β-,γ−NaxCo

Cited by 30 publications

References 30 publications

Ground-state phase diagram of NaxCoO2: correlation of Na ordering with CoO2stacking sequences

Ground-state phase diagram of NaxCoO2: correlation of Na ordering with CoO2stacking sequences

Layered P2-NaxMn3/4Ni1/4O2 Cathode Materials For Sodium-Ion Batteries: Synthesis, Electrochemistry and Influence of Ambient Storage

LiCrO2 Under Pressure: In-Situ Structural and Vibrational Studies

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Ground-state phase diagram of Na_xCoO₂: correlation of Na ordering with CoO₂stacking sequences

Ground-state phase diagram of Na_xCoO₂: correlation of Na ordering with CoO₂stacking sequences