Structural Analysis of Pure and Electrochemically Lithiated SiO Using Neutron Elastic Scattering

Nagao, Yasutaka; Sakaguchi, Hiroki; Honda, Hitohiko; Fukunaga, Toshiharu; Esaka, Takao

doi:10.1149/1.1787173

Cited by 123 publications

(112 citation statements)

References 17 publications

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“…25,33,34,36 Additionally, peaks of Li x Si at 98.4 eV and 98.9 eV are clearly identifiable. 25,33,34,36 The presence of Li-Si bonds is not attributed to a Li-Si alloying reaction because it happens at potentials above 0.5 V. 17 However, the intrinsic SiO 2 layer on Si(100) reacts with Li + , resulting in a partial conversion of the surface oxide to Li 2 O and lithium silicates Li 2 Si 2 O 5 at 0.5 V. [37][38][39][40] The presence of SiOF in the samples from FEC-and VC-containing electrolytes as indicated by the signals at 105.1 and 105.6 eV, is fully consistent with the corresponding F 1s XPS spectra ( Figure 6). 33,34,36 The Si-O peaks from SiO 2 at 103.6 and 104.2 eV 19,33,34,36 and a small amount of lithium silicates at 101.0 and 101.6 eV 33,34,36 can also be observed.…”

Section: Resultsmentioning

confidence: 99%

The Mechanism of SEI Formation on a Single Crystal Si(100) Electrode

Vogl

Lux

Crumlin

et al. 2015

J. Electrochem. Soc.

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A fundamental study of interfacial phenomena on a Si(100) single crystal electrode in organic carbonate-based electrolytes was carried out. The SEI formation on the Si(100) single crystal electrode was investigated as a function of the electrolyte composition, electrode potential and Li x Si lithiation degree. Fourier transform infrared spectroscopy (FTIR) and X-ray photon spectroscopy (XPS) studies of the SEI layer during early stages of SEI formation indicate a strong dependence of the SEI composition on the electrolyte composition. However, the influence of the electrolyte composition becomes negligible at low potentials, when lithium alloys with Si and forms amorphous Li Currently, graphite is the most common negative electrode material in commercial lithium ion batteries for portable electronics. [1][2][3] However, lithium ion batteries for large-scale transportation applications require new inexpensive electrode materials with higher specific capacity. For decades, silicon has been considered as a promising negative electrode material, mainly because of its high specific capacity of ca. 3500 mAh/g 4 and its abundance in the earth crust. [4][5][6] The key problems that prevent its widespread use are large, up to ∼300 % volumetric changes during lithiation/delithiation processes and interfacial instability of lithium silicides in organic solvent based electrolytes. 6-12The resultant poor electrochemical cycling performance and large irreversible capacities during formation and operation of the Si negative electrode contribute to rapid degradation and failure of the battery. 6,7,13 The solid electrolyte interphase (SEI) layer, which forms at the electrode/electrolyte interface during the initial charge/discharge cycles, is the key component that determines the long-term stability and cycling behavior of carbonaceous and intermetallic negative Li-ion battery electrodes.14-16 Electrolyte reduction and SEI layer formation on a Si electrode usually take place at potentials below 1.8 V vs. Li/Li + and accompany the formation of Li-Si phases, the so-called "Si-Li alloying" process at E <0.4 V vs. Li/Li + . 17 The exact mechanism of the SEI formation processes on Si, the SEI composition and the effect on the Si electrode electrochemical cycling performance is not well understood. 18 On the other hand, SEI-forming electrolyte additives such as vinylene carbonate (VC) and fluoroethylene carbonate (FEC) are known to alter the composition and properties of the SEI on Si and improve the electrode electrochemical performance. [19][20][21] Interestingly, recent model studies on Sn single crystal electrodes in organic carbonate electrolytes revealed a strong correlation between the crystal surface orientation and the SEI composition.22,23 A similar study of the composition of the SEI on a silicon monocrystal electrode showed strong effects of different SEI formation protocols, presence/absence of intrinsic SiO 2 , electrolyte composition and impurities e.g., HF. [24][25][26] Also graphite exhibits different SEI layer compos...

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Section: Resultsmentioning

confidence: 99%

The Mechanism of SEI Formation on a Single Crystal Si(100) Electrode

Vogl

Lux

Crumlin

et al. 2015

J. Electrochem. Soc.

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“…Nagao et al reported the formation of Li-Si alloys and Li 2 O after the electrochemical insertion of lithium ion by neutron elastic scattering measurements. 8 Miyachi et al used X-ray photoelectron spectroscopy to elucidate that Li-Si alloys, Li 2 O, and lithium silicates were formed after the first charge.…”

Section: Resultsmentioning

confidence: 99%

Kinetics of Electrochemical Insertion and Extraction of Lithium Ion at SiO

Yamada

Iriyama

Abe

et al. 2010

J. Electrochem. Soc.

135

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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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“…2.1 SiO-C electrodes prepared by the addition of LiMgPO 4 powder Carbon-coated SiO (SiO-C) particles with average diameters of ca. 6 µm were used in the present work.…”

Section: Methodsmentioning

confidence: 99%

“…1 In recent years, many researchers have focused on the development of SiO-based anode materials. [2][3][4][5][6][7][8][9][10][11][12][13] We have reported that SiO-C electrodes containing a small amount of A-Fe 2 O 3 fine powder as conversion electrodes exhibited high capacity (ca. 1300 mAh g ¹1 ) and good performance as compared with SiO-C electrodes.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of High-capacity SiO-C Anodes Containing Olivine-type LiMgPO<sub>4</sub> Compounds for Lithium Secondary Batteries

2015

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The anode properties of carbon-coated SiO (SiO-C) electrode materials containing a small amount of olivine-type LiMgPO 4 powder as the additive were investigated in a lithium cell. The 2 wt% LiMgPO 4 (LMP)-containing SiO-C anode exhibited a high charge/discharge capacity of 1500 mAh g −1 (versus SiO) and good cycle performance. In addition, the high-rate discharge performance was improved by the addition of LMP. The thermal stability of the electrode material was studied by differential scanning calorimetry (DSC). The thermal stability of the SiO-C anode material was improved by the addition of LMP powder.

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Structural Analysis of Pure and Electrochemically Lithiated SiO Using Neutron Elastic Scattering

Cited by 123 publications

References 17 publications

The Mechanism of SEI Formation on a Single Crystal Si(100) Electrode

The Mechanism of SEI Formation on a Single Crystal Si(100) Electrode

Kinetics of Electrochemical Insertion and Extraction of Lithium Ion at SiO

Characteristics of High-capacity SiO-C Anodes Containing Olivine-type LiMgPO<sub>4</sub> Compounds for Lithium Secondary Batteries

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