10.1021/acsaem.8b00608.s001
F. Jeschull
F.
Jeschull
J. Maibach
J.
Maibach
R. Félix
R.
Félix
M. Wohlfahrt-Mehrens
M.
Wohlfahrt-Mehrens
K. Edström
K.
Edström
M. Memm
M.
Memm
D. Brandell
D.
Brandell
Solid
Electrolyte Interphase (SEI) of Water-Processed
Graphite Electrodes Examined in a 65 mAh Full Cell Configuration
American Chemical Society
2018
SEI layer components
binder materials
polymer depletion
counter electrode
sodium carboxymethyl cellulose
Solid Electrolyte Interphase
CMC-Na
electrolyte salt degradation
ion migration
SEI composition
Water-Processed Graphite Electrodes Examined
water-processed graphite electrodes
PES
11 nm
photoelectron spectroscopy
Cell Configuration Electrode binders
binder impact
65 mAh
surface concentration
surface layer
SBR
NMP
SEI layer thickness
SEI thickness correlates
pilot scale
sodium salt deposits
LiFePO 4
PAA-Na component
production costs
2018-09-05 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Solid_Electrolyte_Interphase_SEI_of_Water-Processed_Graphite_Electrodes_Examined_in_a_65_mAh_Full_Cell_Configuration/7098770
Electrode
binders, such as sodium carboxymethyl cellulose (CMC-Na),
styrene–butadiene rubber (SBR) and poly(sodium acrylate) (PAA-Na)
are commonly applied binder materials for the manufacture of electrodes
from aqueous slurries. Their processability in water has considerable
advantages over slurries based on <i>N</i>-methylpyrrolidone
(NMP) considering toxicity, environment and production costs. In this
study, water-processed graphite electrodes containing either CMC-Na:SBR,
PAA-Na, or CMC-Na:PAA-Na as binders have been prepared on a pilot
scale, cycled in graphite||LiFePO<sub>4</sub> Li-ion battery cells
and analyzed post-mortem with respect to the binder impact on the
SEI composition, using in-house (1486.6 eV) and synchrotron-based
(2300 eV) photoelectron spectroscopy (PES). The estimated SEI layer
thickness was smaller than 11 nm for all samples and decreased in
the order: PAA-Na > CMC-Na:SBR > CMC-Na:PAA-Na. The SEI thickness
correlates with the surface concentration of CMC-Na, for example,
the CMC-Na:PAA-Na mixture showed signs of polymer depletion of the
PAA-Na component. The SEI layer components are largely comparable
to those formed on a conventional graphite:poly(vinylidene difluoride)
(PVdF) electrode. However, the SEI is complemented, by notable amounts
of carboxylates and alkoxides, whose formation is favored in water-based
negative electrodes. Additionally, more electrolyte salt degradation
is observed in formulations comprising PAA-Na. The choice of the binder
for the negative electrode had little impact on the surface layer
formed on the LiFePO<sub>4</sub> positive electrode, except for different
contents of sodium salt deposits, as a result of ion migration from
the counter electrode.