EV Battery Innovation Special Report - November 2023 - 18
Emerging Plasma FIB-SEM Techniques
details this method can reveal to guide
the next generation of Li-ion batteries.2,3
Battery Analysis and Imaging
Typical approaches for electrode
characterization utilize some combination
of multi-scale imaging and elemental
analysis techniques. For instance, X-ray
tomography is capable of generating
3D reconstructions of whole electrode
volumes, but its limited resolution makes
it difficult to resolve porous electrode
structures and other phases within the
electrode, such as binder and carbon.
However, as a nondestructive method,
(A)
(B)
it can identify regions of interest in
the large electrode volume for further
analysis with other higher-resolution
techniques. Scanning electron microscopy
(SEM), for example, provides highresolution
2D images of electrodes, and
can be paired with focused ion beam
(FIB) serial sectioning to produce a
series of sequential 2D cross-section
images that are recombined into a
3D representation of the electrode.
Traditionally, this serial sectioning is
accomplished by a gallium FIB. With
such liquid-metal ion sources (LMIS),
field emission at a fine tungsten tip
(C)
20
40
60
80
100
50 μm
(D)
(E)
50 μm
(F)
O
O
20
40
60
80
100
50 μm
(G)
(H)
50 μm
(I)
O
O
20
40
60
80
100
50 μm
50 μm
O
O
20 40 60 80 100120
Distance from the Current Collector (μm)
Figure 2: Visualization of phase distribution in LNMO electrodes, comparing dry and slurry-based
methods for electrode manufacturing. PFIB cross-sections show (A) Dry-LNMO along with slurry-based
LNMO produced with (D) Super C65 carbon or (G) VGCF. Corresponding color segmentation and phase.
20 40 60 80 100
Distance from the Current Collector (μm)
20 40
60
80
Distance from the Current Collector (μm)
is used to produce a beam of ionized
liquid metal gallium. The impact of the
high-energy gallium ions then mills
away surface atoms from the sample.
Unfortunately, Ga-FIB produces a
relative low collision energy, and it
would take an impractical amount
of time to section the large volumes
needed to fully analyze thick electrodes.
Additionally, gallium ions can interact
adversely with a number of materials
(i.e., lithium metal, forming Li-Ga
alloys),4
potentially distorting results.
LNMO
VGCF
Porosity
Plasma FIB, meanwhile, utilizes a range
of gas sources to form a high-energy
beam of plasma ions. The higher collision
energy of these ions compared to Ga+
results in more efficient material removal.
Additionally, the flexibility to choose
from several gas species (Xe+, Ar+, N+,
and O+) allows the milling conditions
to be tailored to the material, ensuring
the surface created by the PFIB is
optimized for subsequent SEM imaging.
LNMO
VGCF
Porosity
Recent Applications of PFIB-SEM
Analysis in Batteries
PFIB-SEM analysis of novel battery
LNMO
VGCF
Porosity
electrodes was recently demonstrated
in a collaboration between Thermo
Fisher Scientific and Professor Shirley
Meng's group at the University of
Chicago. Large-area 2D imaging was
paired with 3D tomography to reveal
critical microstructural details for
thick Li-ion electrodes across their
lifetime, particularly for different LNMO
electrode manufacturing methods.2,3
Processing Methods
There are two main approaches
Figure 4: As next-generation EVs arrive on the market, safer and cheaper battery materials with
high energy density will be needed.
18 NOVEMBER 2023
currently being used for electrode
manufacturing: wet and dry processing.
The conventional slurry-based wetprocessing
approach applies the
electrode materials in a liquid suspension
that is subsequently dried to form the
electrode layer. Scalability and cost
continue to challenge industrial-scale
slurry deposition, however, as the
solvents necessary (i.e., NMP, N-methyl2-pyrrolidone)
are toxic and must be
carefully recycled, this results in a lengthy
and expensive process.5
In dry coating,
the electrode materials are instead
EV BATTERY INNOVATION SPECIAL REPORT
Slurry-VGCF
Slurry-SC65
Dry-VGCF
Phase Percentage (%)
Phase Percentage (%)
Phase Percentage (%)
EV Battery Innovation Special Report - November 2023
Table of Contents for the Digital Edition of EV Battery Innovation Special Report - November 2023
EV Battery Innovation Special Report - November 2023 - Cov1
EV Battery Innovation Special Report - November 2023 - Cov2
EV Battery Innovation Special Report - November 2023 - 1
EV Battery Innovation Special Report - November 2023 - 2
EV Battery Innovation Special Report - November 2023 - 3
EV Battery Innovation Special Report - November 2023 - 4
EV Battery Innovation Special Report - November 2023 - 5
EV Battery Innovation Special Report - November 2023 - 6
EV Battery Innovation Special Report - November 2023 - 7
EV Battery Innovation Special Report - November 2023 - 8
EV Battery Innovation Special Report - November 2023 - 9
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EV Battery Innovation Special Report - November 2023 - 11
EV Battery Innovation Special Report - November 2023 - 12
EV Battery Innovation Special Report - November 2023 - 13
EV Battery Innovation Special Report - November 2023 - 14
EV Battery Innovation Special Report - November 2023 - 15
EV Battery Innovation Special Report - November 2023 - 16
EV Battery Innovation Special Report - November 2023 - 17
EV Battery Innovation Special Report - November 2023 - 18
EV Battery Innovation Special Report - November 2023 - 19
EV Battery Innovation Special Report - November 2023 - 20
EV Battery Innovation Special Report - November 2023 - 21
EV Battery Innovation Special Report - November 2023 - 22
EV Battery Innovation Special Report - November 2023 - 23
EV Battery Innovation Special Report - November 2023 - 24
EV Battery Innovation Special Report - November 2023 - 25
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EV Battery Innovation Special Report - November 2023 - 28
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