Composition and Evolution
of the Solid-Electrolyte Interphase in Na<sub>2</sub>Ti<sub>3</sub>O<sub>7</sub> Electrodes for Na-Ion Batteries: XPS and Auger Parameter
Analysis
Miguel A. Muñoz-Márquez
Maider Zarrabeitia
Elizabeth Castillo-Martínez
Aitor Eguía-Barrio
Teófilo Rojo
Montse Casas-Cabanas
10.1021/acsami.5b01375.s001
https://acs.figshare.com/articles/journal_contribution/Composition_and_Evolution_of_the_Solid_Electrolyte_Interphase_in_Na_sub_2_sub_Ti_sub_3_sub_O_sub_7_sub_Electrodes_for_Na_Ion_Batteries_XPS_and_Auger_Parameter_Analysis/2176378
Na<sub>2</sub>Ti<sub>3</sub>O<sub>7</sub> is considered a promising negative electrode for Na-ion batteries;
however, poor capacity retention has been reported and the stability
of the solid-electrolyte interphase (SEI) could be one of the main
actors of this underperformance. The composition and evolution of
the SEI in Na<sub>2</sub>Ti<sub>3</sub>O<sub>7</sub> electrodes is
hereby studied by means of X-ray photoelectron spectroscopy (XPS).
To overcome typical XPS limitations in the photoelectron energy assignments,
the analysis of the Auger parameter is here proposed for the first
time in battery materials characterization. We have found that the
electrode/electrolyte interface formed upon discharge, mostly composed
by carbonates and semicarbonates (Na<sub>2</sub>CO<sub>3</sub>, NaCO<sub>3</sub>R), fluorides (NaF), chlorides (NaCl) and poly(ethylene oxide)s,
is unstable upon electrochemical cycling. Additionally, solid state
nuclear magnetic resonance (NMR) studies prove the reaction of the
polyvinylidene difluoride (PVdF) binder with sodium. The powerful
approach used in this work, namely Auger parameter study, enables
us to correctly determine the composition of the electrode surface
layer without any interference from surface charging or absolute binding
energy calibration effects. As a result, the suitability for Na-ion
batteries of binders and electrolytes widely used for Li-ion batteries
is questioned here.
2015-04-15 00:00:00
Na 2Ti Electrodes
Auger parameter
electrochemical cycling
Auger Parameter AnalysisNa 2Ti
Na 2Ti electrodes
Na 2CO NaCO 3R fluorides
batterie
binder
photoelectron energy assignments
Auger parameter study
SEI
electrode surface layer
NMR
capacity retention
battery materials characterization
binding energy calibration effects
XPS limitations
polyvinylidene difluoride