The large Debye–Scherrer camera installed at SPring-8 BL02B2 for charge density studies

Nishibori, Eiji; Takata, Masaki; Kato, Kenichi; Sakata, Makoto; Kubota, Yoshiki; Aoyagi, Shinobu; Kuroiwa, Yoshihiro; Yamakata, Masaaki; Ikeda, Naoshi

doi:10.1016/s0168-9002(01)00639-8

Cited by 447 publications

(275 citation statements)

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“…Synchrotron X-ray diffraction patterns of Na 2 CoPO 4 F were collected at beam line BL02B2, SPring-8 in Japan, equipped with a large Debye-Scherrer camera. 22 To minimize the effect of X-ray absorption by samples, a wavelength of incident X-ray beam was set to 0.5 ¡ using a silicon monochromator, which was calibrated with a CeO 2 standard. For electrochemical tests, coin-type cells (R2032 type) were assembled in an Ar filled glove box to evaluate the electrode performance of Na 2 CoPO 4 F. Positive electrodes consisted of 80 wt% prepared materials (Na 2 CoPO 4 F with carbon), 10 wt% acetylene black, and 10 wt% poly(vinylidene fluoride), which were mixed with NMP solvent, and resultant slurry was pasted onto Al foil, and then dried at 80°C in vacuum.…”

Section: Methodsmentioning

confidence: 99%

Na2CoPO4F as a High-voltage Electrode Material for Na-ion Batteries

et al. 2014

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A sodium-containing layered cobalt fluorophosphate, Na 2 CoPO 4 F, is prepared by a solid-state method. Electrode performance of the Na 2 CoPO 4 F is first examined as a positive electrode material for non-aqueous Na batteries. The carbon-modified Na 2 CoPO 4 F delivers 100 mAh g −1 of initial discharge capacity with a nearly flat voltage plateau at approximately 4.3 V vs. Na metal. The estimated energy density as a positive electrode material reaches 407 Wh kg −1 based on metallic sodium. Na 2 CoPO 4 F exhibits the highest operating voltage in a series of Na 2 MePO 4 F (Me = Fe, Co, and Mn).

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Section: Methodsmentioning

confidence: 99%

Na2CoPO4F as a High-voltage Electrode Material for Na-ion Batteries

et al. 2014

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“…The XRD pattern of the Mn-PBA films were obtained using the synchrotron radiation X-ray source at the BL02B2 beamline [28] of SPring-8. The films were carefully removed by a microspatula in an Ar-filled grove box.…”

Section: X-ray Diffraction and X-ray Absorption Spectroscopymentioning

confidence: 99%

Low Voltage Charge/Discharge Behavior of Manganese Hexacyanoferrate

2017

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Abstract:Recently, Prussian blue analogues (PBAs) have been reported to exhibit a low voltage charge/discharge behavior with high capacity (300-545 mAh/g) in lithium-ion secondary batteries (LIBs). To clarify the mechanism of low voltage behavior, we performed ex situ synchrotron radiation X-ray diffraction (XRD) and ex situ X-ray absorption spectroscopy (XAS) of a film of Na 1.34 Mn[Fe(CN) 6 ] 0.84 ·3.4H 2 O without air exposure. After the 1st discharge process, the XRD patterns and X-ray absorption spectra around the Fe and Mn K edges reveal formation of Fe and Mn metals. After the charge process, the XRD pattern reveals formation of Fe 2 O 3 . Based on these observations, we ascribed the low voltage behavior mainly to the conversion reaction of Fe 2 O 3 : 6e − + Fe 2 O 3 + 6Li + 2Fe +3Li 2 O.

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“…Synchrotron X-ray powder diffraction (SXRPD) data of BaNbO 2 N and SrNbO 2 N were measured at 300 K using monochromatized X-ray [wavelength = 0.399204(1) ¡] at the BL02B2 beamline 31) of SPring-8, Japan. Structure analysis was carried out by the Rietveld method using the program RIETAN-FP.…”

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Crystal-structure and electron-density analyses of the perovskite-type oxynitrides BaNbO<sub>2</sub>N and SrNbO<sub>2</sub>N through synchrotron X-ray powder diffraction

Fujii

Shimada

Yashima

2017

J. Ceram. Soc. Japan

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Crystal structure and electron-density distribution of the perovskite-type oxynitrides BaNbO 2 N and SrNbO 2 N have been analyzed by the synchrotron X-ray powder diffraction, Rietveld and maximum-entropy methods. In both BaNbO 2 N and SrNbO 2 N, the electron-density levels along the Nb(O,N) bonds are significantly higher than those along the Ba(O,N) and Sr(O,N) bonds, which indicates higher covalency of the Nb(O,N) bonds. The Nb(O,N) bonds in SrNbO 2 N have higher electron-density levels than that in BaNbO 2 N, which suggests higher covalency of Nb(O,N) bonds in SrNbO 2 N. The higher covalency of SrNbO 2 N cannot explain its wider band gap E g than E g of BaNbO 2 N. The wider E g of SrNbO 2 N compared to BaNbO 2 N is attributable to the smaller Nb(O,N)Nb¤ angles of SrNbO 2 N.©2017 The Ceramic Society of Japan. All rights reserved.Key-words : Perovskite-type oxynitrides, Synchrotron X-ray powder diffraction, Electron-density distribution, Maximum-entropy method [Received August 29, 2017; Accepted September 15, 2017; Published online October 4, 2017] Perovskite-type oxynitrides (AB(O,N) 3 ; A and B are relatively large-and small-sized cations, respectively.) have received much attention because of their possible applications such as photocatalysts, 1)7) pigments, 8)10) and dielectrics. 11)14) Nitrogen has higher energy level of 2p orbital than oxygen. Therefore, oxynitrides generally have narrower band gaps compared to oxides, which enable visible-light absorption. Furthermore, nitrogen has lower electronegativity than oxygen, and BN bonds are more covalent compared to BO bonds. The higher covalency is known to make wider valence band width resulting in narrower band gap. 15),16) Thus, it is important to understand the covalent character of BO bonds in AB(O,N) 3 . The covalent bonds in crystalline materials can be investigated by (i) theoretical methods such as density functional theory (DFT)-based calculations, 17)20) and (ii) electron-density analysis based on the X-ray diffraction data.19)25) In particular, the latter technique is important, because it provides the experimental evidence for the covalent bonds in the crystal structures.19)25) In this work, we aim to obtain the experimental evidence of the covalent bond characters between Nb and (O,N) in BaNbO 2 N and SrNbO 2 N by electron-density analysis using the synchrotron X-ray powder diffraction data. BaNbO 2 N and SrNbO 2 N are important materials because these are known to exhibit photocatalytic activities by visible light irradiation. 5),7) However, the nature of the covalency of chemical bonds in these materials has not been investigated by the electrondensity analysis, although there were some theoretical investigations of the electronic structures. Synchrotron X-ray powder diffraction (SXRPD) data of BaNbO 2 N and SrNbO 2 N were measured at 300 K using monochromatized X-ray [wavelength = 0.399204(1) ¡] at the BL02B2 beamline 31) of SPring-8, Japan. Structure analysis was carried out by the Rietveld method using the program RIETAN-FP.32) The SXR...

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The large Debye–Scherrer camera installed at SPring-8 BL02B2 for charge density studies

Cited by 447 publications

References 5 publications

Na2CoPO4F as a High-voltage Electrode Material for Na-ion Batteries

Na2CoPO4F as a High-voltage Electrode Material for Na-ion Batteries

Low Voltage Charge/Discharge Behavior of Manganese Hexacyanoferrate

Crystal-structure and electron-density analyses of the perovskite-type oxynitrides BaNbO<sub>2</sub>N and SrNbO<sub>2</sub>N through synchrotron X-ray powder diffraction

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