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@INPROCEEDINGS{Valencia:1021020,
      author       = {Valencia, Helen and Rapp, Philip and Graf, Maximilian and
                      Gasteiger, Hubert A. and Basak, Shibabrata and Eichel,
                      Rüdiger-A. and Mayer, Joachim},
      title        = {{S}ilicon microparticles for {L}i-ion batteries: {T}racking
                      {C}rystalline-{A}morphous transition},
      reportid     = {FZJ-2024-00480},
      year         = {2023},
      abstract     = {The improvement of modern Li-ion batteries (LIBs) is an
                      important step in the development of energy storage systems
                      with regard to the growing market of electric vehicles and
                      the realization of the European goal for climate neutrality
                      by 2050 [1].Silicon (Si) is one of the most promising anodes
                      for next-generation LIBs, with its bestselling point being
                      the theoretical capacity of 3579 mAh/g which is
                      approximately ten-fold than that of the commonly used
                      graphite-based materials used nowadays [2-4]. However, the
                      $~300\%$ volume change during (de)lithiation, which also
                      results in crystalline-amorphous transition, limits the
                      commercialization of Si-based anodes, particularly the Si
                      microparticles. The crystalline-amorphous transitions during
                      (de)lithiation, caused by Li-ions that travel into and out
                      of the crystalline Si, caused degradation. One approach to
                      reducing the degradation is to operate the Si anode under
                      its capacity limit, e.g., by using only ~30 $\%$ of the
                      capacity the volume expansion is reduced to only one-third
                      of the maximal expansion and leaving part of the crystalline
                      Si phase unchanged during lithiation. This allows the Si
                      anode to cycle over 200 times. [5] In order to further
                      understand the lithiation process and the resulting capacity
                      fading due to degradation within the Si microparticles, one
                      needs to have an in-depth insight into the structural
                      arrangements within the Si microparticles. Transmission
                      electron microscopy (TEM) is the method of choice to study
                      morphology and chemical composition of the crystalline and
                      amorphous phases within partially lithiated polycrystalline
                      Si microparticles. For the TEM investigation, FIB lamellas
                      are prepared from the 5-10 µm pristine and cycled
                      (lithiated/delithiated) particles. Bright-field (BF)
                      imaging, selected area electron diffraction (SAED) and
                      energy dispersive X-ray spectroscopy (EDX) revealed the
                      presence of the crystalline phase and the complex vein-like
                      amorphous Si phase within the cycled microparticles, the
                      latter not being present in the pristine Si microparticles
                      (Figure 1). This shows the complex expansion of the
                      amorphous phase not only present at the Si microparticle
                      shell but also along stacking faults and grain boundaries.},
      month         = {Feb},
      date          = {2023-02-26},
      organization  = {Microscopy Conference 2023, Dramstadt
                       (Fed Rep Germany), 26 Feb 2023 - 2 Mar
                       2023},
      subtyp        = {After Call},
      cin          = {IEK-9 / ER-C-2},
      cid          = {I:(DE-Juel1)IEK-9-20110218 / I:(DE-Juel1)ER-C-2-20170209},
      pnm          = {1223 - Batteries in Application (POF4-122)},
      pid          = {G:(DE-HGF)POF4-1223},
      typ          = {PUB:(DE-HGF)6},
      url          = {https://juser.fz-juelich.de/record/1021020},
}