Crystal structure and ionic conductivity of the new cobalt polyphosphate NaCo(PO3)3

Smida, Youssef Ben; Guesmi, Abderrahmen; Georges, Samuel; Avdeev, Maxim; Zid, Mohamed Faouzi

doi:10.1016/j.jssc.2015.11.029

Cited by 18 publications

(23 citation statements)

References 25 publications

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“…In an effort to increase the electrochemical activity, recently NaCo(PO 3 ) 3 has been reported having an orthorhombic structure (S.G. Pa-3) very similar to NaFe(PO 3 ) 3 . [116] With relatively lower Na + migration barrier of 1.1 eV, it delivers a reversible discharge capacity over 50 mAh g −1 involving a Co 3+ /Co 2+ redox potential at 3.2 V versus Na/Na + . Limited by theoretical capacity, metaphosphates have poor practical application.…”

Section: Metaphosphatesmentioning

confidence: 99%

Polyanionic Insertion Materials for Sodium‐Ion Batteries

Barpanda

Lander

Nishimura

et al. 2018

Advanced Energy Materials

322

185

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future. [1][2][3] To avoid this scenario, Na-ion batteries can play a vital role. Contrary to Li, Na has abundant natural resources with even geographic distribution. In addition to being the fifth-most abundant element in earth's crust, the Na charge carrier is also the second lightest alkali element in the periodic table. In this context, mammoth effort has been geared to build efficient Na-ion batteries. 2D layered oxides are the most important category of cathode materials, which has been proven by their dominance in commercial Li-ion batteries. Although the only difference is the intercalation ion, the electrochemical behavior and structure transformation of Na analogs are very different to that in Li-ion batteries. These are mainly caused by the larger size of Na, which can stabilize the layered structure (empirical stability criterion for ABO 2 : r B /r A <0.86 for α-NaFeO 2 type structure) and thus prevent Na from occupying tetrahedral sites and promote Na cation ordering. [31] NaMO 2 compounds can retain the layered structure for all 3d transition elements M, whereas Co and Ni are the exclusive 3d transition metals that can offer ground state stability of layered structure of LiMO 2 . Thereby, intensive survey for a variety of NaMO 2 compounds was performed. [4][5][6]32] However, even with the inherently stable structural nature of NaMO 2 compounds, they usually suffer from a slopy voltage profile distributed over a wide potential range at lower average voltage (at least 0.3 V and in many cases over 0.5 V) as compared to the Li analog, identifying only a few complicated compounds that can generate >3.5 V versus Na/Na + .Development of high voltage cathode materials is of paramount importance for Na batteries, bearing in mind the relative difference in anode potential of Li/Li + : −3.03 V and Na/ Na + : −2.71 V versus NHE. With an essential lack of high-voltage layered cathode material, polyanion compounds form a major stream toward the stable cathode materials operating over 3.5 V in Na batteries. Light and small polyanion units such as (SO 4 ) 2− , (PO 4 ) 3− , (BO 3 ) 3− , (SiO 4 ) 4− , which have also been widely explored as major components in Li-ion battery cathodes, offer two major functions; i) raising the redox potential largely as compared to the simple oxides with identical redox couple, and ii) providing inherent safety to the battery system. These two very important features led olivine LiFePO 4 to a great commercial success in the Li battery market over a decade ago, [35,37,38,63] proving that additional atoms X (X = P in this case), other than Efficient energy storage is a driving factor propelling myriads of mobile electronics, electric vehicles and stationary electric grid storage. Li-ion batteries have realized these goals in a commercially viable manner with ever increasing penetration to different technology sectors across the globe. While these electronic devices are more evident and appealing to consumers, there has been a growing concern for micro-to-mega grid storage systems. Ove...

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Section: Metaphosphatesmentioning

confidence: 99%

Polyanionic Insertion Materials for Sodium‐Ion Batteries

Barpanda

Lander

Nishimura

et al. 2018

Advanced Energy Materials

322

185

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“…Starting from the higher frequency in the FTIR-spectra, peaks at approximately 1263 (range of 1190 to 1300) cm À1 and 1037 to 1177 cm À1 correspond to n as (PO 2 À ) and n s (PO 2 À ) stretching vibrations, respectively. [16,22] Weak features at 902 to 1019 and 678 to 821 cm À1 are the n as (POP) and n s (POP) stretching vibrations, respectively. Further, phosphate bending motions contributing into a stronger band envelope between 420 and 630 cm À1 .…”

Section: Angewandte Chemiementioning

confidence: 99%

“…The Na-Co-P-O (1:1:3:9) compositional ratio was maintained after combustion as well as after the solid-state method, both cases are accompanied by final annealing of the intermediates in air as well as in Ar (refer to the Supporting Information for experimental procedures). [15,16] All the catalysts processed in this way are found to exhibit good OER activity with respectable current density. NCoM-Cb-Ar manifested surprisingly high OER performance in alkaline solution, arising from its local structure with chemical coupling between NaCo(PO 3 ) 3 and partially graphitized carbon resulted from the oxygen-deprived annealing.…”

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confidence: 95%

“…The features of vibrational interactions and band overlapping of the phosphate network for all four samples are stacked and shown in Figure S5a. [16,22] Weak features at 902 to 1019 and 678 to 821 cm À1 are the n as (POP) and n s (POP) stretching vibrations, respectively. [18][19][20] The Raman spectrum of the NCoM-Cb-Ar sample has D and G bands ( Figure S5b) suggesting the presence of partially graphitized carbon.…”

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Sodium Cobalt Metaphosphate as an Efficient Oxygen Evolution Reaction Catalyst in Alkaline Solution

et al. 2019

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Sodium cobalt metaphosphate [NaCo(PO3)3] has CoO octahedra (CoO6) and shows superior oxygen evolution reaction (OER) activity in alkaline solution, comparable with the state‐of‐the‐art precious‐metal RuO2 catalyst. OER catalysts of this metaphosphate are prepared by combustion (Cb) and solid‐state (SS) methods. The combustion‐assisted method offers a facile synthesis and one‐step carbon composite formation. Unusually high catalytic activity was observed in NCoM‐Cb‐Ar and could be due to chemical coupling effects between NaCo(PO3)3 and partially graphitized carbon. This novel electrocatalyst exhibits very small overpotential of 340 mV with high mass activity of 532 A g−1. Good charge transfer abilities and chemical coupling between NaCo(PO3)3 and amorphous carbon gives the OER activity in NCoM‐Cb‐Ar.

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“…Besides, if the electrical properties of many phosphate or arsenate materials have been largely investigated, only few studies were devoted to the samples densification and then the relative density and to the different parameters that can have an effect on. Indeed, it has been demonstrated in many previous studies [13][14][15][16][17] that the electrical behavior is closely related to the relative density, which points out the importance of its control. Moreover, it has been shown in many works that the best densities were obtained for arsenates rather than phosphates [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

The electrical behaviors of the melilite-like solid solutions Na2Co(P2−xAsx)O7 (x = 0.5; 1): effect of the P/As substitution on structure and electrical properties

et al. 2019

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The melilite-like Na 2 CoP 2 O 7 diphosphate, due to its structural features, is a promising material for sodium-ion battery cathodes. Aiming at improving the conduction properties of this phase, the P 5+ ions were partially substituted by As 5+ ones, and two Na 2 Co(P 2−x As x)O 7 (x = 0.5 and x = 1) solid solutions were synthesized. The purity of the obtained solid solutions was confirmed by powder X-ray diffraction, and their electrical properties were investigated using complex impedance spectroscopy. The effects of the P/As substitution on sintering temperature, relative density and ionic conductivity were studied. The mean particle size was reduced by ball milling. The sintering temperature decreased from 680 to 640 °C from the pure phosphate to the arsenic richest solid solution, respectively, and the relative density of the pellets obtained after 120-min ball milling of the three samples showed an increase from 90 to 94%. The conductivity of the samples with the same relative density 90% was compared. The main effect of the substitution is a strong increase in the electrical conductivity, by about 10 4 , and a significant decrease in the activation energy. Further studies involving simulations will be carried out to correlate these observations with the structural features of the substituted phases. The obtained results may be significant for overall sodium-ion battery performance. Keywords Na 2 Co(P 2−x As x)O 7 solid solutions • X-ray diffraction • Ball milling • Structure • Ionic conductivity * Hammouda Chebbi,

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Crystal structure and ionic conductivity of the new cobalt polyphosphate NaCo(PO3)3

Cited by 18 publications

References 25 publications

Polyanionic Insertion Materials for Sodium‐Ion Batteries

Polyanionic Insertion Materials for Sodium‐Ion Batteries

Sodium Cobalt Metaphosphate as an Efficient Oxygen Evolution Reaction Catalyst in Alkaline Solution

The electrical behaviors of the melilite-like solid solutions Na2Co(P2−xAsx)O7 (x = 0.5; 1): effect of the P/As substitution on structure and electrical properties

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