In Situ Transmission Electron Microsopy of Oxide Shell-Induced Pore Formation in (De)lithiated Silicon Nanowires

Adkins, Emily R.; Jiang, Taizhi; Luo, Langli; Wang, Chong -Min; Korgel, Brian A.

doi:10.1021/acsenergylett.8b01904

Title: In Situ Transmission Electron Microsopy of Oxide Shell-Induced Pore Formation in (De)lithiated Silicon Nanowires

Journal Article · Fri Oct 19 00:00:00 EDT 2018 · ACS Energy Letters

DOI:https://doi.org/10.1021/acsenergylett.8b01904· OSTI ID:1479093

Adkins, Emily R. ^[1]; Jiang, Taizhi ^[1];

^[2];

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Univ. of Texas at Austin, Austin, TX (United States)
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Silicon (Si) nanowires with a silicon oxide (SiO_x) shell undergoing lithiation and delithiation were examined by in situ transmission electron microscopy (TEM). Large pores formed in the nanowires during the delithiation cycle. We found that the oxide shell constrains the expansion of the Si nanowires during lithitation and then induces pore formation in the nanowires. We propose that the SiO_x shell prevents the vacancies that result from the loss of lithium from escaping the Si core, leading to pore nucleation and growth. It is also possible that the difference in mechanical properties of the expanding and contracting Si nanowire and SiO_x shell contribute to the observed pore formation. Furthermore, this in situ study reaffirms the need to directly observe structural changes that occur during cycling in battery materials, especially when modified by coatings.

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