Advancing Lithium-Ion Battery Research Using FTIR
App Note / Case Study
Last Updated: July 1, 2024
(+ more)
Published: October 24, 2023
Credit: iStock
The demand for lithium-ion batteries (LIBs) is growing, however, there remains a need to increase energy capacity, reduce charging times, and find cost-effective, safer materials.
Fourier Transform Infrared Spectroscopy (FTIR), a method that measures IR radiation absorption, provide insights into the material such as to the composition, structure, and identity.
This whitepaper highlights how FTIR can be used to enhance the development of LIBs by rapidly characterizing their raw materials and components.
Download this white paper to find out about:
- The role FTIR can play in LIB development and research
- The flexibility FTIR provides during LIB material analysis
- How FTIR advances knowledge of LIB materials
White Paper
Energy and Material
Science Research
Authors
Wesam Alwan and
Fabian Zieschang
Agilent Technologies, Inc.
Introduction
There is increasing demand for lithium-ion batteries (LIBs), especially from
the electric vehicle sector. This uptake is partially due to government policies
and legislation to reduce carbon emissions associated with the use of internal
combustion engines. While commercially available LIBs with higher performance are
becoming cheaper, there are still opportunities for development within the sector.
Researchers around the globe are looking at ways to increase the energy capacity of
batteries, reduce charging times, and find cheaper and safer alternative materials for
LIB components.1
Advancing Research of Lithium-Ion
Batteries Using the Agilent Cary 630
FTIR Spectrometer
Lithium-ion battery studies published by global
research groups
2
This white paper provides examples of how the Agilent Cary
630 FTIR spectrometer has been used by leading research
groups for the analysis and characterization of LIB materials
and components.
FTIR spectroscopy is a well-established and powerful
analytical technique that provides information on the
composition of materials. Even though it is a mature
spectroscopic technique, advances in FTIR sampling
interfaces are continuing to extend its flexibility and use.
The quick and easy qualitative and quantitative analysis of
polymers and electrolytes are example applications where
sampling interfaces have broadened the scope of FTIR.
The Cary 630 FTIR spectrometer
The Cary 630 FTIR spectrometer is an ultra-compact, flexible,
and high-performance benchtop FTIR instrument that
includes many ease-of-use features to simplify operation
by nonexpert users. The innovative Cary 630 FTIR can be
configured with a range of interchangeable sampling modules
that integrate with the optomechanical system of the
instrument (Figure 1).
The versatile modular design means that the Cary 630 FTIR
provides the configuration flexibility needed for the robust and
reliable analysis of materials used in LIBs. Various materials
are used within the main components of a LIB that include
the anode, cathode, electrolyte (e.g., solvents and salts), and
separator materials.
In a multi-user setting, a robust and reliable FTIR instrument
is key to preventing downtime and reducing the risk of
compromised data. A walk-up system that is easy to learn
and that requires minimal training is an asset in a busy lab
environment. The field-proven, robust optomechanical system
of the Cary 630 FTIR has been shown to deliver outstanding
performance and reproducibility.
The Cary 630 FTIR spectrometer is controlled by the
powerful Agilent MicroLab software, which uses an intuitive
pictorial interface to guide users through the steps of the
analysis, from sample introduction to reporting. The software
automatically detects which sampling accessory is installed,
applies the required settings, and loads instructive images
that are specific to the sampling accessory.
Figure 1. Interchangeable sampling modules for the Agilent Cary 630 FTIR facilitates lithium-ion battery research.
3
The software allows analysts to identify unknown
compounds by automatically comparing the FTIR spectrum
of an unknown sample with a library of spectra of known
compounds. The Cary 630 FTIR spectrometer can also
provide quantitative information (e.g., salts concentration in
electrolyte solution). The software automatically performs
all required calculations and provides the analyst with the
final answer. The results are color-coded to help analysts
interpret the data and take appropriate action (Figure 2). The
FTIR spectrum of a sample provides valuable insights for
the characterization of LIB components, which are useful for
research studies.
Figure 3. Analysis of a sheet-material using an Agilent Cary 630 FTIR with
ATR sampling module.
Instantly receive color-coded,
actionable results
Start the analysis Follow picture-driven software guidance
Figure 2. Three simple steps using Agilent MicroLab software and an Agilent Cary 630 FTIR make performing an analysis straightforward and decision making
easier. The picture-driven software also reduces training needs and minimizes the risk of user-based errors.
The Cary 630 FTIR spectrometer with the MicroLab software
form an ideal solution for the analysis of diverse material
types. Once a sampling module has been selected for the
630 FTIR, a method can be tailored to the application. As an
example, Figure 3 shows the Cary 630 FTIR equipped with the
attenuated total reflectance (ATR) module for the analysis of
materials in sheet-form.
Agilent also offers advanced FTIR spectroscopy software for
the Cary 630 FTIR; MicroLab Expert provides a higher level
of flexibility and spectral visualization for more sophisticated
data processing.
4
Highly aligned graphene oxide for lithium storage in
lithium-ion battery through a novel microfluidic process:
The pulse freezing2
Yifan Liu and coworkers reported a new method to fabricate
vertically aligned graphene oxide (GO) films as free-standing
carbon lithium hosts for LIBs with enhanced performance.
This process led to increased levels of microstructure
porosity and vertical alignment of the GO films. The alignment
and porous microstructures increase both electron and ion
transfer capabilities across the prepared film. To characterize
these GO films, the Cary 630 FTIR was used to assess the
C–OH groups removal based on thermal treatment. The
removal of the C-OH groups was confirmed by a significant
decrease in the peak intensity at 3,429 cm−1 on thermally
treated GO films compared to non-treated GO films.
Atmospheric moisture and oxygen can significantly affect
the characterization of LIB components such as electrolyte
salts, e.g., lithium hexafluorophosphate (LiPF6
). So, it is
recommended that such experiments should be performed
in an oxygen and moisture-controlled environment. The
small footprint of the Cary 630 FTIR, ease-of-use features,
such as changing modules, and its robustness, make it
ideal for operation in a glovebox-controlled environment, as
represented by Figure 4.
Lithium-ion batteries research
applications using FTIR
Research-groups located around the world have used Agilent
FTIR instrumentation as an integral solution for the analysis
and characterization of LIB components, as summarized in
the following examples:
Figure 4. Agilent Cary 630 FTIR spectrometer inside a glovebox in which the moisture or oxygen level can be controlled. An ideal setup for LIB
research applications.
5
Lithiating magneto-ionics in a rechargeable battery3
Yong Hu and team reported that the reversible
lithiation/delithiation in a molecular magneto-ionic material
(i.e. the cathode in a rechargeable LIB) accurately monitors
its real-time state of charge through a dynamic tunability of
magnetic ordering. In the study, the Cary 630 FTIR was used
to study compound changes due to lithiation. The system was
used to study the vibrational shift of the compound in pristine
condition. A peak at 2,108 cm–1 corresponding to the C≡N
bond was observed, but upon lithiation, the peak disappeared,
and two new peaks emerged at lower wavenumbers of 2,075
and 2,012 cm–1.
ZIF 67 derived Co–Sn composites with N-doped
nanoporous carbon as anode material for
Li-ion batteries4
Sheeraz Ashraf et al., synthesized a composite of SnO2
with nanoporous carbon using ZIF-67, a 2-methylimidazole
cobalt salt. ZIF-67 creates a framework composed of a
Co–Sn alloy and Sn–C network that is responsible for the
enhanced structural stability of the composite material. In
the study, the Cary 630 FTIR was used to analyze the type
of bonding present at the molecular level between the three
synthesized composites.
Novel polymer coating for chemically absorbing CO2
for
safe Li-ion battery5
Jean-Christophe Daigle et al., reported on the utilization of a
mixture of polymers that can chemically absorb CO2
, including
the coating of aluminum foils, which serve as trapping
sheets. The authors concluded that the coating method is
economically viable, industrially applicable, and permits the
fabrication of safe high-power lithium-ion batteries based
on large format cells with significant cycle life potential.
In the study, the Cary 630 FTIR equipped with an ATR was
used to measure the trapping sheets at different times and
temperatures to monitor degradation and the conversion
rates of epoxy groups.
A versatile method for grafting polymers onto Li4
Ti5
O12
particles applicable to lithium-ion batteries6
Jean-Christophe Daigle et al., reported a novel and versatile
method of grafting polymers onto lithium titanium oxide
(LTO) by dispersion mediated interfacial polymerization. The
method can produce thin and homogenous polymer films that
are useful for battery applications. The Cary 630 FTIR system
was used to characterize the polymeric shells by monitoring
the appearance of the polymer's -CH2
-CH characteristic
signals at 2,900 cm–1.
A new method for determining the concentration of
electrolyte components in lithium-ion cells, using Fourier
transform infrared spectroscopy and machine learning7
L. D. Ellis and coworkers introduced a new method for
determining unknown concentrations of major components in
typical LIB electrolytes. A quick, cheap, and accurate method
was generated by utilizing the Cary 630 FTIR equipped
with a germanium attenuated total reflectance (ATR) and
machine learning. Machine learning techniques were used
to match features of the FTIR spectrum of an unknown
electrolyte to the same features of a database of FTIR
spectra with known compositions. The researchers reported
that using the method, the concentration of LiPF6
could be
determined by FTIR with similar accuracy and precision as
an inductively coupled plasma optical emission spectrometry
(ICP-OES) method.
High performance solid polymer electrolyte with
graphene oxide nanosheets8
In this study, Mengying Yuan and co-authors introduced
two-dimensional graphene oxide (GO) sheets with a high
surface area and excellent mechanical properties into
a solid polyethylene oxide/lithium salt electrolyte. The
GO sheets improved ion conductivity and increased the
tensile strength of the polymer electrolyte and appeared to
significantly enhance the performance of the lithium-ion
battery. To measure the lithium salt dissociation fraction,
the Cary 630 FTIR system with MicroLab software was
used. The dissociation fraction was obtained as the ratio
of the respective areas under the peaks located in two
specific ranges: the 620 to 624 cm–1 range, representing the
dissociated "free" ClO4
–1 ions, and the 630 to 635 cm–1, range
representing the ion-pair LiClO4
.
User-friendly freeware for determining the concentration
of electrolyte components in lithium-ion cells using
Fourier transform infrared spectroscopy, Beer's Law, and
machine learning9
Sam Buteau et al., refined the model based on FTIR
measurements7
to determine the concentration of
electrolytes including LiPF6
, ethylene carbonate (EC),
ethyl‑methyl carbonate (EMC), dimethyl-carbonate (DMC),
and diethyl-carbonate (DEC). In the study, the Cary 630 FTIR
equipped with a germanium ATR was used to characterize the
composition of the electrolytes. The model could be applied
to the fast determination of the composition of unknown
electrolyte samples, with a specified set of components.
www.agilent.com/chem/cary630
DE38081608
This information is subject to change without notice.
© Agilent Technologies, Inc. 2023
Printed in the USA, August 9, 2023
5994-6144EN
Conclusion
The Agilent Cary 630 FTIR is an effective spectrometer
for the characterization of various materials of interest to
researchers working on lithium-ion batteries. It can be fitted
with a range of fully-interchangeable sampling technologies,
ensuring that the best sampling technique can be used for
the application.
The summaries of the research papers have shown the
flexibility and usefulness of the Cary 630 FTIR in expanding
knowledge of materials that are needed to improve the
performance and safety of LIBs.
References
1. Masias, A.; Marcicki, J.; Paxton. W. A. Opportunities
and Challenges of Lithium Ion Batteries in Automotive
Applications, ACS Energy Letters, 2021 6(2), 621–630.
2. Liu, Y. et al. Highly Aligned Graphene Oxide for Lithium
Storage in Lithium-Ion Battery Through A Novel
Microfluidic Process: The Pulse Freezing, Adv. Mater.
Interfaces, 2023, 10, 2201612.
3. Hu Y et al. Lithiating Magneto-Ionics in a
Rechargeable Battery, Proc. Natl. Acad. Sci. USA, 2022,
21;119(25):e2122866119.
4. Sheeraz, A. et al, ZIF 67 Derived Co–Sn Composites with
N-doped Nanoporous Carbon as Anode Material for Li-ion
Batteries. Mater. Chem. Phys 2021, 270, 124824.
5. Daigle J. C. et al. Novel Polymer Coating for Chemically
Absorbing CO2
for Safe Li-ion Battery. Sci. Rep. 2020
25;10(1), 10305.
6. Daiglea, J-C. et al, A Versatile Method for Grafting
Polymers onto Li4
Ti5
O12 Particles Applicable to Lithium-Ion
Batteries, J. Power Sources, 421, 2019, 116–123.
7. Ellis, L. D. et al. A New Method for Determining the
Concentration of Electrolyte Components in Lithium-Ion
Cells, Using Fourier Transform Infrared Spectroscopy and
Machine Learning, J. Electrochem. Soc. 2018, 165, A256.
8. Yuan, M. et al. High Performance Solid Polymer
Electrolyte with Graphene Oxide Nanosheets, RSC Adv.,
2014, 4, 59637.
9. Buteau, S. et al, User-Friendly Freeware for Determining
the Concentration of Electrolyte Components in
Lithium‑Ion Cells Using Fourier Transform Infrared
Spectroscopy, Beer's Law, and Machine Learning,
J. Electrochem. Soc., 2019, 166 A3102.
Further information
– Agilent Cary 630 FTIR Spectrometer
– Agilent MicroLab Software
– Agilent MicroLab Expert Software
– FTIR Analysis & Applications Guide
– FTIR Spectroscopy Basics - FAQs
– ATR-FTIR Spectroscopy Overview
Brought to you by
Download This App Note for FREE Now!
Information you provide will be shared with the sponsors for this content. Technology Networks or its sponsors may contact you to offer you content or products based on your interest in this topic. You may opt-out at any time.