Structural studies of the new carbon-coated silicon anode materials using synchrotron-based in situ XRD

Yang, Xiao‐Qing; McBreen, J.; Yoon, Won‐Sub; Yoshio, Masaki; Wang, Hongyu; Fukuda, Kenji; Umeno, Tatsuo

doi:10.1016/s1388-2481(02)00483-6

Cited by 68 publications

(29 citation statements)

References 9 publications

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“…A single plateau was seen in the charge-discharge curve, which did not correspond to any of the four Li-Si phases. From the differential capacity curves [79] and in-situ XRD studies [80] during Li insertion/extraction, it was concluded that during the first insertion process, Li + saturates the carbons first and then starts to alloy with Si, so Li-saturated carbon and amorphous Li-Si alloy coexist. During the second cycle, Li alloys with C and amorphous Si simultaneously.…”

Section: Si/c Composite Anodes Prepared By Pyrolysis Reactions or Tvdmentioning

confidence: 99%

Nano- and bulk-silicon-based insertion anodes for lithium-ion secondary cells

Kasavajjula

Wang

Appleby

2007

Journal of Power Sources

2,393

1,914

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Section: Si/c Composite Anodes Prepared By Pyrolysis Reactions or Tvdmentioning

confidence: 99%

Nano- and bulk-silicon-based insertion anodes for lithium-ion secondary cells

Kasavajjula

Wang

Appleby

2007

Journal of Power Sources

2,393

1,914

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“…Especially, lithium-alloys with silicon 25 and aluminum 26 attracted the interested of researchers because of their high specific capacity, good reversibility and mitigation of lithium dendrites. The morphological changes of silicon caused by (de-)alloying have been investigated, e.g., by means of in situ lab or synchrotron based X-ray diffraction (XRD), [27][28][29][30] nuclear magnetic resonance spectroscopy (NMR), 11,[31][32][33][34] and in situ transmission electron microscopy (TEM), 12,[35][36][37][38] which provided valuable insights into the phase transition of crystalline silicon as well as the volumetric expansion and strain-induced fracture of silicon particles within the first cycles. As pointed out by McDowell et al, 13 most of the these studies either deal with the degradation of individual particles or investigate primarily the first few cycles.…”

Section: −1mentioning

confidence: 99%

Morphological Changes of Silicon Nanoparticles and the Influence of Cutoff Potentials in Silicon-Graphite Electrodes

Wetjen

Solchenbach

Pritzl

et al. 2018

J. Electrochem. Soc.

114

135

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Silicon-graphite electrodes usually exhibit improved cycling stability when limiting the capacity exchanged by the silicon particles per cycle. Yet, the influence of the upper and the lower cutoff potential was repeatedly shown to differ significantly. In the present study, we address this discrepancy by investigating two distinct degradation phenomena occurring in silicon-graphite electrodes, namely (i) the roughening of the silicon particles upon repeated (de-)lithiation which leads to increased irreversible capacity losses, and (ii) the decay in the reversible capacity which mainly originates from increased electronic interparticle resistances between the silicon particles. First, we investigate the cycling stability and polarization of the silicon-graphite electrodes in dependence on different cutoff potentials using pseudo full-cells with capacitively oversized LiFePO 4 cathodes. Further, we characterize postmortem the morphological changes of the silicon nanoparticles by means of scanning transmission electron microscopy (STEM) and energy dispersive spectroscopy (EDS) as a function of the cycle number. To evaluate the degradation of the entire electrode coating, we finally complement our investigation by impedance spectroscopy (EIS) with a gold-wire micro-reference electrode and post-mortem analyses of the electrode structure and coating thickness by cross-sectional SEM. Silicon is among the most promising anode materials for future lithium-ion batteries.1,2 For example, a prismatic hard case cell comprising a silicon-carbon anode with 1000 mAh gand an NMC811 cathode would offer a specific energy of up to ∼280 Wh kgcell . 3 In contrast to state-of-the-art graphite electrodes, where lithium is inserted into the interlayers between the graphene sheets, silicon reacts with lithium and forms Li x Si alloys.4-6 Because the (de-)alloying reaction allows a higher lithium uptake per silicon atom (3579 mAh g −1Si , Li 15 Si 4 ) compared to the intercalation of lithium into the graphite host structure (372 mAh g −1 C , LiC 6 ), silicon offers an about ∼10 times larger theoretical specific capacity. However, while the intercalation chemistry reveals excellent cycling stability with only minor irreversible changes of the graphite's morphology (ca. +10%), 8 the (de-)alloying reaction causes significant morphological and chemical changes to the silicon particles, including (i) a large volume expansion of up to +280% and (ii) repeated breakage and formation of Si-Si bonds, which leads to severe mechanical stress and particle fracturing. [9][10][11][12] Upon continued cycling, these morphological changes cause a rapid capacity decay of silicon-based electrodes, which is largely driven by the electrical isolation of the fractured silicon particles.13-17 Nanometer-sized structures, including nanoparticles and nanowires, were shown to mitigate the mechanical stress which results from volumetric changes during the (de-)alloying reaction.12,18-20 However, there exists a trade-off, because the reduction of the particle size als...

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“…Furthermore, the doping of phosphorus is found to be the key process for the improvement of the cycle retention through the enhancement of the conductivity of the composite [14]. However, in the case of the material containing silicon, the degradation of the cycle performance is still observed, due to the volume changes during cycling, even though the graphite phase mitigates the electrode cyclability by acting as a mechanical and electrochemical buffer in the composite [15]. The volume expansion of silicon during its alloying with lithium, leading to the formation of cracks which generate a dead volume, and the subsequent volume shrinkage during de-alloying, generate an electronically inactive zone which is isolated from the electron transport path [16,17].…”

Section: Resultsmentioning

confidence: 99%

Electrochemical characteristics of phosphorus doped silicon and graphite composite for the anode materials of lithium secondary batteries

et al. 2008

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Poly-crystalline silicon particles with a diameter of 80∼100 nm were synthesized by the plasma arc discharge method. Natural graphite, poly-crystalline silicon, poly-crystalline silicon/graphite composite and phosphorus doped poly-crystalline silicon/graphite composite particles were used as the anode materials of lithium secondary batteries and their electrochemical performances were compared. The phosphorus component on the surface and internal structure of the silicon particles were observed by XPS and SIMS analyses, respectively. In our experiments, the phosphorus doped silicon/graphite composite electrode exhibited better cycle performance than the intrinsic silicon/ graphite composite electrode. The discharge capacity retention efficiency of the intrinsic silicon/graphite composite and phosphorus doped silicon/graphite composite electrodes after 20 cycles were 8.5% and 75%, respectively. The doping of phosphorus leads to an increase in the electrical conductivity of silicon, which plays an important role in enhancing the cycle performance. The incorporation of silicon into graphite has a synergetic effect on the mitigation of the volume change and conducting medium in the composite electrode during the charge-discharge reaction.

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Structural studies of the new carbon-coated silicon anode materials using synchrotron-based in situ XRD

Cited by 68 publications

References 9 publications

Nano- and bulk-silicon-based insertion anodes for lithium-ion secondary cells

Nano- and bulk-silicon-based insertion anodes for lithium-ion secondary cells

Morphological Changes of Silicon Nanoparticles and the Influence of Cutoff Potentials in Silicon-Graphite Electrodes

Electrochemical characteristics of phosphorus doped silicon and graphite composite for the anode materials of lithium secondary batteries

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