ChemInform Abstract: Investigations on Bi<sub>25</sub>FeO<sub>40</sub> Powders Synthesized by Hydrothermal and Combustion‐Like Processes.

Koeferstein, Roberto; Buttlar, Toni; Ebbinghaus, Stefan G.

doi:10.1002/chin.201436007

Cited by 3 publications

(3 citation statements)

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“…The optical band gap energies were obtained from diffuse reflectance spectra using the KubelkaÀMunk theory. The optical band gap (E g ) can be described by equation (2) [52]:…”

Section: Sintering Microstructure and Phase Composition Of The Ceramicsmentioning

confidence: 99%

Effect of sintering additives on the densification and dielectric properties of Sr0.5Ba0.5Nb2O6 ceramics synthesized by a soft-chemistry method

Köferstein¹

2022

Preprint

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Nano-crystalline Sr0.5Ba0.5Nb2O6 powders with addition of LiNbO3 or LiF as sintering additives were prepared bya soft-chemistry synthesis using polyethylene glycol. Calcination at 600 ?C results in nanocrystalline powders(dcryst. ? 30 nm) which were sintered between 1000 and 1300 ?C to ceramic bodies. By addition of 10 and 20 mol% LiNbO3, the sintering temperature was reduced by about 200 K and the activation energy of the initial stage ofsintering decreases from 386 to 271 kJ mol?1. The sintering aid improves the grain growth and dense ceramicbodies were obtained after sintering at 1125 ?C for 1 h. A higher LiNbO3 content favors the formation of a pillarlikemicrostructure. XRD patterns of ceramics sintered above 1000 ?C show only reflections of the Sr0.5Ba0.5Nb2O6phase indicating an incorporation of LiNbO3 in the Sr0.5Ba0.5Nb2O6 structure. Dielectric measurements reveal adiffuse phase transition and a relaxor-like behavior. The phase transition temperature (Tm) depends on the sinteringconditions and is between 117 and 127 ?C for 10 mol% LiNbO3, which is very close to pureSr0.5Ba0.5Nb2O6, while addition of 20 mol% shifts Tm to around 200 ?C and the transition becomes slightly morediffuse. The optical band gap of the samples is ? 3.3 eV and depends slightly on the sintering conditions. We alsotried LiF as sintering aid, but this leads to the formation of considerable amounts of secondary phases in theceramics and relative densities of only 82%.

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“…The optical band gap energies were obtained from diffuse reflectance spectra using the KubelkaÀMunk theory. The optical band gap (E g ) can be described by equation (2) [52]:…”

Section: Sintering Microstructure and Phase Composition Of The Ceramicsmentioning

confidence: 99%

Effect of sintering additives on the densification and dielectric properties of Sr0.5Ba0.5Nb2O6 ceramics synthesized by a soft-chemistry method

Köferstein¹

2022

Preprint

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“…Bi 25 FeO 40 is an analogue to γ-Bi 2 O 3 , which typically holds a body centered cubic structure with a space group of I23, where there could have a lot of oxygen and ionic vacancies. 24,25 In this paper, we studied 30% Li-doped Bi 25 FeO 40 as a possible electrode for lithium battery applications and a detailed discharge mechanism was further investigated using a combination of in operando X-ray diffraction (XRD) and X-ray absorption near edge structure analysis (XANES).…”

Section: Introductionmentioning

confidence: 99%

In Situ Studies of 30% Li-Doped Bi₂₅FeO₄₀ Conversion Type Lithium Battery Electrodes

et al. 2019

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One of the important discharge mechanisms for lithium batteries is the conversion reaction mechanism, where a metal oxide (fluoride) can decompose into metallic nanoparticles embedded in a Li 2 O (LiF) matrix. Here, 30% Li-doped Bi 25 FeO 40 is successfully synthesized and displays an electrochemical discharge capacity of ∼300 mAh/g above 1.5 V (vs Li/Li + ). During the electrochemical cycling process, 30% Li-doped Bi 25 FeO 40 is decomposed into metallic Bi. During the subsequent charging process, the metallic bismuth can be first converted into an amorphous bismuth oxide phase, which contributed to the electrochemical discharge activities observed between 2 and 2.5 V. At a higher charging voltage between 3.5 and 5 V, metallic Bi can be oxidized to BiO x 2– O 3–2 x – , which contributes to the discharge activities observed above 2.5 V. Using graphite as current collectors can prevent the corrosion from O – species and the discharge capacity is greatly enhanced at the voltage region between 1.5 and 2.5 V. This work provides a deeper understanding over the role of oxygen ions during the conversion reaction process and is beneficial for the future design of battery systems based on the conversion reaction.

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“…The detailed studies of metal metastannates on different aspects of the manufacturing method have been developed to enhance the applications of metal metastannates prepared by a range of processes, such as a solid-state reaction 6 , a coprecipitation method 7 , sol-gel 8 , a combustion method 9 , a precursor route 10,11 , a microwave synthesis 12 , a polymerized complex method 13 , a molten salt synthesis 14 , a pulsed laser deposition 15 and a self-heat-sustained method 16,17 . The advantages of microwave synthesis are to bring a very short reaction time, a small particle size and a narrow particle size distribution.…”

Section: Introductionmentioning

confidence: 99%

A Solvothermal Process to Synthesize Barium Metastannate Nanoparticles Assisted by Microwave Irradiation

Lim¹

2013

Asian J. Chem.

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Barium metatstannate (BaSnO3) nanoparticles were synthesized successfully using a facile microwave solvothermal route followed by further heat-treatment. Well-crystallized BaSnO3 nanoparticles were formed after heat-treatment at 800 ºC for 3 h showing a fine and homogeneous morphology with particle sizes of 60-80 nm. The synthesized BaSnO3 nanoparticles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy.

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ChemInform Abstract: Investigations on Bi₂₅FeO₄₀ Powders Synthesized by Hydrothermal and Combustion‐Like Processes.

Cited by 3 publications

References 1 publication

Effect of sintering additives on the densification and dielectric properties of Sr0.5Ba0.5Nb2O6 ceramics synthesized by a soft-chemistry method

Effect of sintering additives on the densification and dielectric properties of Sr0.5Ba0.5Nb2O6 ceramics synthesized by a soft-chemistry method

In Situ Studies of 30% Li-Doped Bi₂₅FeO₄₀ Conversion Type Lithium Battery Electrodes

A Solvothermal Process to Synthesize Barium Metastannate Nanoparticles Assisted by Microwave Irradiation

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ChemInform Abstract: Investigations on Bi25FeO40 Powders Synthesized by Hydrothermal and Combustion‐Like Processes.

Cited by 3 publications

References 1 publication

Effect of sintering additives on the densification and dielectric properties of Sr0.5Ba0.5Nb2O6 ceramics synthesized by a soft-chemistry method

Effect of sintering additives on the densification and dielectric properties of Sr0.5Ba0.5Nb2O6 ceramics synthesized by a soft-chemistry method

In Situ Studies of 30% Li-Doped Bi25FeO40 Conversion Type Lithium Battery Electrodes

A Solvothermal Process to Synthesize Barium Metastannate Nanoparticles Assisted by Microwave Irradiation

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ChemInform Abstract: Investigations on Bi₂₅FeO₄₀ Powders Synthesized by Hydrothermal and Combustion‐Like Processes.

In Situ Studies of 30% Li-Doped Bi₂₅FeO₄₀ Conversion Type Lithium Battery Electrodes