Intrinsic blocking effect of SiOx on the side reaction with a LiPF6-based electrolyte

Xiao, Zhexi; Yu, Chunhui; Lin, Xianqing; Chen, Xiao; Zhang, Chenxi; Jiang, Helen; Wei, Fei

doi:10.1016/j.cattod.2020.05.023

Cited by 13 publications

(9 citation statements)

References 38 publications

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“…SiO x undergoes a volume change during lithiation and delithiation. Our previous work [ 32–34 ] also found that the occurrence of side reactions with the electrolyte results in a thick SEI. These changes squeeze the CNTs and produce significant stress changes, which may lead to the loss of electrical contact between SiO x and the conductive network.…”

Section: Introductionmentioning

confidence: 97%

Single‐Walled Carbon Nanotube Film as an Efficient Conductive Network for Si‐Based Anodes

Zhu

Xiao

Yue

et al. 2023

Adv Funct Materials

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Silicon-based anodes are considered ideal candidate materials for nextgeneration lithium-ion batteries due to their high capacity. However, the low conductivity and large volume variations during cycling inevitably result in inferior cyclic stability. Herein, a dry method without binders is designed to fabricate Si-based electrodes with single-walled carbon nanotubes (SWCNTs) network and to explore the different mechanisms between SWCNT and multiwalled carbon nanotubes (MWCNTs) as a conductive network. As expected, higher initial discharge capacity (1785 mAh g −1 ), higher initial Coulombic efficiency (ICE, 81.52%) and outstanding cyclic stability are obtained from the SiO x @C|SWCNT anodes. Furthermore, its lithium-ion diffusion coefficient (D Li+ ) is 3-4 orders of magnitude higher than that of SiO x @C|MWCNT. The underlying mechanism is clarified by in situ Raman spectroscopy and theoretical analysis. It is found that the SWCNTs can maintain good contact with SiO x @C even under tensile stresses up to 6.2 GPa, while the MWCNTs lose electrical contact due to alternating compressive stress up to 8.9 GPa and tensile stress up to 2.5 GPa during long-term cycling. Under such very large stresses, the more flexible SWCNTs and their stronger van der Waals forces ensure that SiO x @C still has good contact with SWCNTs.

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Section: Introductionmentioning

confidence: 97%

Single‐Walled Carbon Nanotube Film as an Efficient Conductive Network for Si‐Based Anodes

Zhu

Xiao

Yue

et al. 2023

Adv Funct Materials

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“…The presence of the F element, combined with the analysis of XRD patterns, initially determined that the new substance generated by SEM was a Li 2 SiF 6 crystal. As reported in the literature, , the main product of the reaction of SiO with LiPF 6 -based electrolyte is Li 2 SiF 6 , which is one of the main components of the solid electrolyte interface (SEI) that prevents electron diffusion and slows down the Li + transport rate. To some extent, Li 2 SiF 6 can inhibit the occurrence of side reactions between SiO and the electrolyte.…”

Section: Resultsmentioning

confidence: 97%

Li₂SiF₆ In Situ Embedded in an Amorphous SiO Matrix to Inhibit Volume Expansion during Prelithiation

Zhang,

Zhong,

Yan

et al. 2024

ACS Appl. Nano Mater.

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Direct contact prelithiation is considered an important means of addressing the low Coulombic efficiency of Si-based anodes. However, few studies have been conducted on the inhibition of volume expansion of Si-based materials and the reduction of side reactions during direct contact prelithiation. In this paper, Li 2 SiF 6 crystals are generated in situ in an amorphous SiO matrix by a thermodynamic reaction between SiO and LiPF 6 , which is from the viewpoint of contact state at the interface between lithium source and negative electrode as well as the construction of mechanical buffer phase. On the one hand, Li 2 SiF 6 crystals can inhibit the volume expansion of SiO during prelithiation. On the other hand, Li 2 SiF 6 crystals act as an interfacial passivation layer to reduce local currents and inhibit the occurrence of side reactions during direct contact prelithiation. The analysis of the results showed that Li 2 SiF 6 crystals were embedded in an amorphous SiO matrix to prepare the SiO/C composite anode, and the strength of the crystals was utilized to inhibit the volume expansion of SiO during the direct contact prelithiation process. Meanwhile, due to its good ionic conductivity, a strong and tough LiF-rich solid electrolyte interphase (SEI) was constructed, which suppressed the volume expansion of the composite anode for the prelithiation process. The full battery assembled with NCM111 positive electrode still exhibits 94.5% capacity retention after 150 cycles at 0.5C current density.

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“…8). [139][140][141][142] Yu et al demonstrated the generation of PF 3 in a reaction between a LiPF 6 -based electrolyte and a silicon anode inside a reactor at 90 °C and conrmed the formation of crystalline Li 2 SiF 6 on the silicon anode by mass spectrometry and X-ray diffraction analysis. 143 The electrically insulating Li 2 SiF 6 (conductivity <10 −10 S cm −1 ) formed on the surface of silicon anodes impedes both lithium-ion and electron transport (Fig.…”

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confidence: 99%

“…143,[145][146][147] However, the carbon coating layer on silicon may catalyze its reaction with LiPF 6 and aggravate the formation of Li 2 SiF 6 . 139,147 To inhibit Li 2 SiF 6 formation, coatings such as titanium nitride and silicon carbide have been proposed. 143,147 Another method of mitigating Li 2 SiF 6 generation and thus securing a long cycle life is the replacement of LiPF 6 with LiFSI or LiTFSI.…”

mentioning

confidence: 99%

Liquid electrolyte chemistries for solid electrolyte interphase construction on silicon and lithium-metal anodes

Choi¹,

Park²,

Kim³

et al. 2023

Chem. Sci.

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Intrinsic blocking effect of SiOx on the side reaction with a LiPF6-based electrolyte

Cited by 13 publications

References 38 publications

Single‐Walled Carbon Nanotube Film as an Efficient Conductive Network for Si‐Based Anodes

Single‐Walled Carbon Nanotube Film as an Efficient Conductive Network for Si‐Based Anodes

Li₂SiF₆ In Situ Embedded in an Amorphous SiO Matrix to Inhibit Volume Expansion during Prelithiation

Liquid electrolyte chemistries for solid electrolyte interphase construction on silicon and lithium-metal anodes

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Intrinsic blocking effect of SiOx on the side reaction with a LiPF6-based electrolyte

Cited by 13 publications

References 38 publications

Single‐Walled Carbon Nanotube Film as an Efficient Conductive Network for Si‐Based Anodes

Single‐Walled Carbon Nanotube Film as an Efficient Conductive Network for Si‐Based Anodes

Li2SiF6 In Situ Embedded in an Amorphous SiO Matrix to Inhibit Volume Expansion during Prelithiation

Liquid electrolyte chemistries for solid electrolyte interphase construction on silicon and lithium-metal anodes

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Product

Resources

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Li₂SiF₆ In Situ Embedded in an Amorphous SiO Matrix to Inhibit Volume Expansion during Prelithiation