The blue allotropic form of Co2+:Na2CoP2O7: optical and magnetic properties, correlation with crystallographic data

Beaury, L.; Derouet, J.; Binet, Laurent; Sanz, Francisca; Ruı́z-Valero, C.

doi:10.1016/j.jssc.2003.11.028

Cited by 32 publications

(23 citation statements)

References 19 publications

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“…Also, some compounds in this family show allotropic behavior. For example, Na 2 CoP 2 O 7 could adopt both tetragonal (blue)14, 16 and triclinic (rose)15 structures depending on synthetic procedures. As a comparison, the X‐ray diffraction (XRD) characterization ( Figure a) indicates that Na 2 FeP 2 O 7 , the material of interest in this study, is isostructural with Na 2 CoP 2 O 7 ‐ rose , adopting the triclinic structure under the space group P1 15.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, Na 2 FeP 2 O 7 mimics Li 2 FeP 2 O 7 in that both materials show outstanding thermal stability up to 500 °C even in the partially charged states (NaFeP 2 O 7 ). To date, a variety of Na‐based pyrophosphates such as NaFeP 2 O 7 ,8, 9 NaVP 2 O 7 ,10 NaMoP 2 O 7 ,11 Na 2 MnP 2 O 7 ,12, 13 Na 2 CoP 2 O 7 ,14–16 Na 2 ZnP 2 O 7 17 and Na 2 CuP 2 O 7 18 have been investigated. While these pyrophosphate materials adopt different crystal structures depending on transition metals, most of them contain open frameworks that could facilitate efficient diffusion of Na ions for battery operation.…”

Section: Introductionmentioning

confidence: 99%

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Na₂FeP₂O₇ as a Promising Iron‐Based Pyrophosphate Cathode for Sodium Rechargeable Batteries: A Combined Experimental and Theoretical Study

Kim

Shakoor

Park

et al. 2012

Adv Funct Materials

338

296

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Considering the promising electrochemical performance of the recently reported pyrophosphate family in lithium ion batteries as well as the increasing importance of sodium ion batteries (SIBs) for emerging large‐scale applications, here, the crystal structure, electrochemical properties, and thermal stability of Na2FeP2O7, the first example ever reported in the pyrophosphate family for SIBs, are investigated. Na2FeP2O7 maintains well‐defined channel structures (triclinic framework under the P1 space group) and exhibits a reversible capacity of ≈90 mAh g−1 with good cycling performance. Both quasi‐equilibrium measurements and first‐principles calculations consistently indicate that Na2FeP2O7 undergoes two kinds of reactions over the entire voltage range of 2.0–4.5 V (vs Na/Na+): a single‐phase reaction around 2.5 V and a series of two‐phase reactions in the voltage range of 3.0–3.25 V. Na2FeP2O7 shows excellent thermal stability up to 500 °C, even in the partially desodiated state (NaFeP2O7), which suggests its safe character, a property that is very critical for large‐scale battery applications.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Na₂FeP₂O₇ as a Promising Iron‐Based Pyrophosphate Cathode for Sodium Rechargeable Batteries: A Combined Experimental and Theoretical Study

Kim

Shakoor

Park

et al. 2012

Adv Funct Materials

338

296

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“…For related structures, see: Adam et al (2008); Nishimura et al (2010); Zhou et al (2011). For related materials with Na + and K + cations, see: Erragh et al (1991); Sanz et al (1999); Beaury et al (2004); Gopalakrishna et al (2005); Bih et al (2006); Guesmi et al (2007). For related structural frameworks, see: Beaury et al (2004); Fagginani & Calvo (1976); Sandströ m et al (2003); Etheredge & Hwu (1995);El Maadi et al (1995); Huang & Hwa (1998);Sanz et al (1999); Erragh et al (1998).…”

Section: Related Literaturementioning

confidence: 99%

Lithium cobalt(II) pyrophosphate, Li_1.86CoP₂O₇, from synchrotron X-ray powder data

et al. 2011

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Key indicators: powder synchrotron study; T = 297 K; mean (O-Li) = 0.020 Å; disorder in main residue; R factor = 0.057; wR factor = 0.080; data-to-parameter ratio = 91.1.Structure refinement of high-resolution X-ray powder diffraction data of the title compound gave the composition Li 1.865 CoP 2 O 7 , which is also verified by the ICP measurement. Two Co sites exist in the structure: one is a CoO 5 square pyramid and the other is a CoO 6 octahedron. They share edges and are further interconnected through P 2 O 7 groups, forming a three-dimensional framework, which exhibits different kinds of intersecting tunnels containing Li cations and could be of great interest in Li ion battery chemistry. The structure also exhibits cation disorder with 13.5% Co residing at the lithium (Li1) site. Co seems to have an average oxidation state of 2.135, as obtained from the strutural stochiometry that closely supports the magnetic susceptibility findings. (1998). Pseudovoigt profile coefficients as parameterized in Thompson et al. (1987) and Finger et al. (1994). Related literature ExperimentalCrystal data

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“…Co 0.1 Zn 0.9 Ga 0.75 Al 1.25 O 4 , [49] SrCo 2 A C H T U N G T R E N N U N G (PO 4 ) 2 , [50] blue polymorph of Na 2 CoP 2 O 7 [51] ), maybe slightly larger. Eventually, the fit gives an expectation value for the spin-allowed transition 4 A 2 !…”

Section: Introductionmentioning

confidence: 99%

Intermediate States on the Way to Edge‐Sharing BO₄ Tetrahedra in M₆B₂₂O₃₉⋅H₂O (M=Fe, Co)

Neumair

Knyrim²,

Oeckler

et al. 2010

Chemistry A European J

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The new borates Fe(II)(6)B(22)O(39)·H(2)O (colourless) and Co(II)(6)B(22)O(39)·H(2)O (dichroic: red/bluish) were synthesised under the high-pressure/high-temperature conditions of 6 GPa and 880 °C (Fe)/950 °C (Co) in a Walker-type multi-anvil apparatus. The compounds crystallise in the orthorhombic space group Pmn2(1) (Z=2) with the lattice parameters a=771.9(2), b=823.4(2), c=1768.0(4) pm, V=1.1237(4) nm(3), R(1)=0.0476, wR(2)=0.0902 (all data) for Fe(6)B(22)O(39)·H(2)O and a=770.1(2), b=817.6(2), c=1746.9(4) pm, V=1.0999(4) nm(3), R(1)=0.0513, wR(2)=0.0939 (all data) for Co(6)B(22)O(39)·H(2)O. The new structure type of M(6)B(22)O(39)·H(2)O (M=Fe, Co) is built up from corner-sharing BO(4) tetrahedra and BO(3) groups, the latter being distorted and close to BO(4) tetrahedra if additional oxygen atoms of the neighbouring BO(4) tetrahedra are considered in the coordination sphere. This situation can be regarded as an intermediate state in the formation of edge-sharing tetrahedra. The structure consists of corrugated multiple layers interconnected by BO(3)/BO(4) groups to form Z-shaped channels. Inside these channels, iron and cobalt show octahedral (M1, M3, M4, M5) and strongly distorted tetrahedral (M2, M6) coordination by oxygen atoms. Co(II)(6)B(22)O(39)·H(2)O is dichroic and the low symmetry of the chromophore [Co(II)O(4)] is reflected by the polarised absorption spectra (Δ(t)=4650 cm(-1), B=878 cm(-1)).

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The blue allotropic form of Co2+:Na2CoP2O7: optical and magnetic properties, correlation with crystallographic data

Cited by 32 publications

References 19 publications

Na₂FeP₂O₇ as a Promising Iron‐Based Pyrophosphate Cathode for Sodium Rechargeable Batteries: A Combined Experimental and Theoretical Study

Na₂FeP₂O₇ as a Promising Iron‐Based Pyrophosphate Cathode for Sodium Rechargeable Batteries: A Combined Experimental and Theoretical Study

Lithium cobalt(II) pyrophosphate, Li_1.86CoP₂O₇, from synchrotron X-ray powder data

Intermediate States on the Way to Edge‐Sharing BO₄ Tetrahedra in M₆B₂₂O₃₉⋅H₂O (M=Fe, Co)

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The blue allotropic form of Co2+:Na2CoP2O7: optical and magnetic properties, correlation with crystallographic data

Cited by 32 publications

References 19 publications

Na2FeP2O7 as a Promising Iron‐Based Pyrophosphate Cathode for Sodium Rechargeable Batteries: A Combined Experimental and Theoretical Study

Na2FeP2O7 as a Promising Iron‐Based Pyrophosphate Cathode for Sodium Rechargeable Batteries: A Combined Experimental and Theoretical Study

Lithium cobalt(II) pyrophosphate, Li1.86CoP2O7, from synchrotron X-ray powder data

Intermediate States on the Way to Edge‐Sharing BO4 Tetrahedra in M6B22O39⋅H2O (M=Fe, Co)

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Na₂FeP₂O₇ as a Promising Iron‐Based Pyrophosphate Cathode for Sodium Rechargeable Batteries: A Combined Experimental and Theoretical Study

Na₂FeP₂O₇ as a Promising Iron‐Based Pyrophosphate Cathode for Sodium Rechargeable Batteries: A Combined Experimental and Theoretical Study

Lithium cobalt(II) pyrophosphate, Li_1.86CoP₂O₇, from synchrotron X-ray powder data

Intermediate States on the Way to Edge‐Sharing BO₄ Tetrahedra in M₆B₂₂O₃₉⋅H₂O (M=Fe, Co)