Premium
Mechanical properties of SiLi x thin films at different stages of electrochemical Li insertion
Author(s) -
Zinn ArndtHendrik,
BorhaniHaghighi Sara,
Ventosa Edgar,
PfetzingMicklich Janine,
Wieczorek Nikolai,
Schuhmann Wolfgang,
Ludwig Alfred
Publication year - 2014
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201431303
Subject(s) - nanoindentation , materials science , amorphous solid , modulus , x ray photoelectron spectroscopy , thin film , electrochemistry , composite material , young's modulus , elastic modulus , analytical chemistry (journal) , nanotechnology , chemical engineering , crystallography , chemistry , electrode , chromatography , engineering
The mechanical properties of amorphous Si thin films, lithiated electrochemically to different SiLi compositions are studied by ex situ nanoindentation. The compositions of the films are adjusted using an electrochemical routine that corrects for the Li consumed by SEI layer growth during initial lithiation. The mechanical properties such as Young's modulus and hardness are derived from nanoindentation. For compositions between Si and SiLi 2.5 the Young's modulus decreases with increasing Li content from ∼160 GPa to ∼8 GPa and the hardness decreases from ∼14 GPa to ∼0.1 GPa. The yield strength values, as deduced from hardness measurements, decrease from ∼5 GPa to 0.05 GPa. AFM imaging is used on the electrochemically cycled films to assess the SEIs impact on the nanomechanical measurements. XPS depth‐profiling of the electrochemically cycled sample indicated a Li concentration gradient across the film thickness.