An interface clusters mixture model for the structure of amorphous silicon monoxide (SiO)

Hohl, A.; Wieder, Thomas; Aken, Peter A. van; Weirich, Thomas E.; Denninger, G.; Vidal, M. A.; Oswald, Steffen; Deneke, Christoph; Mayer, J.; Fuess, Harald

doi:10.1016/s0022-3093(03)00031-0

Cited by 253 publications

(214 citation statements)

References 101 publications

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“…10,11 Kim et al verified the above reaction mechanism by a solid-state 29 Si and 7 Li nuclear magnetic resonance technique, electrochemical dilatometry, and charge-discharge measurement. 12 A reaction at amorphous Si domains is an alloying reaction that occurs reversibly to give the charge-discharge capacity.…”

Section: Resultsmentioning

confidence: 90%

Kinetics of Electrochemical Insertion and Extraction of Lithium Ion at SiO

Yamada

Iriyama

Abe

et al. 2010

J. Electrochem. Soc.

137

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The kinetics of the electrochemical insertion and extraction of lithium ion at silicon monoxide ͑SiO͒ were investigated by ac impedance spectroscopy. The resultant Nyquist plots showed two semicircles at high and middle frequency regions. These two semicircles were attributed to lithium-ion transport resistance in a surface film and alloying reaction resistance ͑charge-transfer resistance͒, respectively. We evaluated the activation energies of the charge-transfer reaction from the temperature dependences of the interfacial conductivities. When an ethylene-carbonate-based electrolyte was used, the activation energy of the charge transfer was 32 kJ mol −1 . This activation energy was much smaller than those at graphite electrode or positive electrode materials ͑around 50 kJ mol −1 or more͒. Based on these results, the charge transfer at SiO is exceptionally fast compared to those at other insertion materials. Furthermore, the activation energies of the charge transfer at SiO remained unchanged in various electrolytes. These results suggest that the charge-transfer kinetics at SiO is not influenced by the desolvation of lithium ion from solvent molecules. Lithium-ion batteries have recently attracted much attention as a power source for electric vehicles ͑EVs͒ and plug-in hybrid EVs. These applications of lithium-ion batteries give severe requirements to electrode materials. One such requirement is a significant improvement in the energy density of electrode materials. Therefore, an alternative electrode material has been explored for a much higher energy density. Among the candidates for a new negative electrode are alloying materials such as Si and Sn.1,2 These materials electrochemically react with lithium to form a lithium alloy that has an extremely high energy density compared to graphite. However, the alloying reaction shows a large volume change in the materials, 3 which leads to capacity fade during charge-discharge cycles. 4 To overcome the problem, silicon monoxide ͑SiO͒ has recently attracted much attention as a next generation negative electrode. 5-13SiO shows a small volume change because it contains a relatively small amount of Si element that is active for the alloying reaction. The discharge capacity of SiO electrodes was reported to be over 600 mAh g −1 in several papers, 9-12 which is much higher than that of a graphite electrode ͑372 mAh g −1 ͒. To commercialize the SiO electrode, we need to consider the rate performance in addition to the energy density. However, there are few reports on the kinetic aspect of alloying materials. Our group focused on the kinetics of charge ͑lithium ion͒-transfer reactions at a graphite/electrolyte interface 14,15 and other interfaces. [16][17][18][19] The activation energies of the charge-transfer reactions were around 50 kJ mol −1 or more, which were higher compared to those of lithium-ion transport in solid [20][21][22][23] or liquid [24][25][26] electrolytes. This is because the desolvation of lithium ion from solvents occurs during the charge transfer at the...

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Section: Resultsmentioning

confidence: 90%

Kinetics of Electrochemical Insertion and Extraction of Lithium Ion at SiO

Yamada

Iriyama

Abe

et al. 2010

J. Electrochem. Soc.

137

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“…During the thermal treatment, the broad PXRD peak around 51 degrees gradually diminished and is most likely associated with amorphous Si clusters or a SiO x interface between domains of ncSi and SiO 2 . 18 Note that with increasing reaction time further coarsening 35 or "pseudo-Ostwald ripening" 23 of ncSi is not rare. We observe that longer heating times at the same temperature result in larger size ncSi, revealed by sharper peaks in PXRD and a red-shifted peak in PL spectra (see ESI †).…”

Section: Dependence Of Ncsi Formation On Thermal Treatment Temperaturementioning

confidence: 99%

“…It has however received very little attention for the batch synthesis of freestanding ncSi. 18 In this context, Liu et al…”

Section: Introductionmentioning

confidence: 99%

Silicon monoxide – a convenient precursor for large scale synthesis of near infrared emitting monodisperse silicon nanocrystals

Sun

Qian

et al. 2016

Nanoscale

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While silicon nanocrystals (ncSi) embedded in silicon dioxide thin films have been intensively studied in physics, the potential of batch synthesis of silicon nanocrystals from the solid-state disproportionation of SiO powder has not drawn much attention in chemistry. Herein we describe some remarkable effects observed in the diffraction, microscopy and spectroscopy of SiO powder upon thermal processing in the temperature range 850-1100 °C. Quantum confinement effects and structural changes of the material related to the size of the silicon nanocrystals nucleated and grown in this way were established by Photoluminescence (PL), Raman, FTIR and UV-Visible spectroscopy, PXRD and STEM, pinpointing that the most significant disproportionation transformations happened in the temperature range between 900 and 950 °C. With this know-how a high yield synthesis was developed that produced polydispersions of decyl-capped, hexanesoluble silicon nanocrystals predominantly with near infrared (NIR) PL. Using size-selective precipitation, these polydispersions were separated into monodisperse fractions, which allowed their PL absolute quantum yield (AQY) to be studied as a function of silicon nanocrystal size. This investigation yielded volcano-shaped plots for the AQY confirming the most efficient PL wavelength for ncSi to be located at around 820-830 nm, which corresponded to a size of 3.5-4.0 nm. This work provides opportunities for applications of size-selected near infrared emitting silicon nanocrystals in biomedical imaging and photothermal therapy. While silicon nanocrystals (ncSi) embedded in silicon dioxide thin films have been intensively studied in physics, the potential of batch synthesis of silicon nanocrystals from the solid-state disproportionation of SiO powder has not drawn much attention in chemistry. Herein we describe some remarkable effects observed in the diffraction, microscopy and spectroscopy of SiO powder upon thermal processing in the temperature range 850-1100°C. Quantum confinement effects and structural changes of the material related to the size of the silicon nanocrystals nucleated and grown in this way were established by Photoluminescence (PL), Raman, FTIR and UV-Visible spectroscopy, PXRD and STEM, pinpointing that the most significant disproportionation transformations happened in the temperature range between 900 and 950°C. With this know-how a high yield synthesis was developed that produced polydispersions of decyl-capped, hexane-soluble silicon nanocrystals predominantly with near infrared (NIR) PL. Using sizeselective precipitation, these polydispersions were separated into monodisperse fractions, which allowed their PL absolute quantum yield (AQY) to be studied as a function of silicon nanocrystal size. This investigation yielded volcano-shaped plots for the AQY confirming the most efficient PL wavelength for ncSi to be located at around 820-830 nm, which corresponded to a size of 3.5-4.0 nm. This work provides opportunities for applications of size-selected near infrared emit...

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“…The two techniques, however, have limitations and our equipment would not allow us to distinguish amorphous concentrations of Si atoms or even crystalline domains if the latter were as small as 1 nm. The question arises because commercial SiO, such as the powder we pressed to prepare our pellets, has been found to be disproportionated into Si and SiO 2 nanometer-sized domains [13,14].…”

Section: Experiments With Ne Matricesmentioning

confidence: 99%

Cosmic dust formation at cryogenic temperatures

Rouillé¹,

Krasnokutski²,

Krebsz³

et al. 2014

Proceedings of the Life Cycle of Dust in the Universe: Observations, Theory, and Laboratory Experiments — PoS(LCDU2013)

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Within a project aimed at studying the formation of interstellar silicates in dense molecular clouds, we have carried out experiments on the accretion of SiO molecules at cryogenic temperatures using SiO-doped superfluid He nanodroplets and solid Ne matrices. Mass spectrometry revealed the formation of Si x O x oligomers in the doped droplets, i.e., at a temperature of 0.37 K. Therefore the reactions that produce the oligomers have no energy barrier at their entrance channel. Reaction energies were experimentally determined and the results of theoretical calculations were found to be consistent with the measurements. Absorption spectroscopy at UV and mid-IR wavelengths was performed at various stages of the annealing of SiO-doped Ne matrices and after their complete evaporation. It showed that the matrices were actually doped with Si x O x (x = 1-3) species which disappeared during annealing to be replaced with a condensate characterized by a broad IR spectrum peaking near 9.5 µm. High-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy investigations showed that the condensate had on the whole a homogeneous, amorphous structure and the formula SiO. Still, the study of the IR spectra indicated some degree of disproportionation which increased during warming from 8 to 294 K. We have concluded that SiO molecules can accrete at temperatures as low as 13 K into a solid compound. These preliminary experiments have demonstrated the relevance of the techniques to the study of accretion at low temperature. More particularly their results allow us to envisage the formation of silicates in the interstellar medium.

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An interface clusters mixture model for the structure of amorphous silicon monoxide (SiO)

Cited by 253 publications

References 101 publications

Kinetics of Electrochemical Insertion and Extraction of Lithium Ion at SiO

Kinetics of Electrochemical Insertion and Extraction of Lithium Ion at SiO

Silicon monoxide – a convenient precursor for large scale synthesis of near infrared emitting monodisperse silicon nanocrystals

Cosmic dust formation at cryogenic temperatures

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