Microscopy and spectroscopy technologies for battery characterization

Improving and safeguarding product performance and cost efficiency across the battery supply chain.

Electron microscopy and spectroscopy techniques provide valuable chemical and structural information from the microscale to the atomic scale. Using electron microscopy, you can study morphology and structure in 2D and 3D across multiple length scales. Spectroscopy adds the complementary capability to investigate chemical changes at the electrode surface and interfaces. Via streamlined workflows and intuitive, industry-specific software, we make these powerful techniques relevant for battery researchers and manufacturers, enhancing ease of use and maximizing the relevance and value of the data generated. Find out more about what these techniques can do and the information they can deliver.

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Scanning electron microscopy for multiscale imaging and analysis

Scanning electron microscope (SEM) provides high-resolution 2D imaging, elemental analysis, and quantitative structural characterization from the microscale down to the nanoscale. It is widely used as an effective characterization tool among battery materials and cell manufacturers during materials R&D, quality control, and failure analysis. The resulting information elucidates how structural features impact battery chemistry, performance, and failure, helping to establish the understanding needed for progress. The broad applicability of SEM presents scientists and engineers with the challenge of characterizing a range of substantially different materials, from electrically insulating, beam-sensitive separator materials to electrically conductive, air-sensitive electrodes. Workflows and software that address these challenges are crucial to realizing the full value of SEM for the battery industry.

Imaging of Li-ion battery cathode particles using Apreo 2 SEM. Sample courtesy of Prof. Y. Shirley Meng, University of Chicago.

We offer SEM techniques directly meet these needs; whether the goal is high-resolution imaging analysis for materials R&D, automated metal impurity particle analysis for quality control, or structural and elemental quantification for failure analysis. Our software solutions provide advanced automation and image interpretation capabilities to maximize the information density that the microscopes can provide.

 

Features and applications:

  • Live, quantitative, elemental mapping for fast elemental and structural analysis on battery materials
  • Automated SEM/EDS workflow for impurity particle analysis for battery production QA/QC
  • Automated image interpretation for quality assessment and failure analysis
  • Inert gas sample protection solutions to observe sample without water or air contamination
  • Advanced low-keV performance on beam-sensitive samples to enable accurate structural characterization without beam damage

High-quality observation and characterization of battery materials via SEM often require an artifact-free surface, which can be difficult to achieve with traditional polishing techniques like grinding or mechanical polishing. The Thermo Scientific™ CleanMill™ Broad Ion Beam System is the complete ion beam polishing solution for SEM applications in battery characterization, enabling optimal imaging and analysis of battery materials (e.g. cathode, anode) where a pristine surface is required, including beam- and air-sensitive materials. It can be used to precisely polish high-quality sample surfaces and cross-sections while completely protecting sample integrity.

Li-ion battery cathode cross-section prepared via CleanMill system and imaged with Apreo 2 SEM.

Focused ion beam scanning electron microscopy for multi-modal analysis at multi-length scale

In situ sample preparation and microstructural characterization with high-resolution imaging have proven to be the keys to advancing battery technologies, linking multiscale and multi-dimensional structures of battery components to their electrochemical performance.

 

The addition of a focused ion beam column to a scanning electron microscope allows you to mill a sample in situ to expose and observe features of interest below the surface. Our Thermo Scientific focused ion beam scanning electron microscopes (FIB-SEMs), provide 2D and 3D image analysis capabilities to develop understanding of battery structure and performance correlations in multiple dimensions. They enable characterization from the millimeter scale to the nanometer scale with key features for different battery applications. FIB-SEMs have been proven to be increasingly vital tools in the battery field, as they enable both fundamental battery materials research as well as quality control (QC) and failure analysis (FA) in battery production.

(a) and (b) NMC cathode cross-section prepared via Thermo Scientific Helios ™ 5 PFIB DualBeam and phase fraction analysis performed via Avizo2D Software; (c) TOF-SIMS analysis of the lithium distribution in NMC cathode; (d) 3D characterization of Li-ion battery graphite anode, data collected via Auto Slice & View Software in Helios 5 Laser PFIB; structural quantification performed via Avizo Software.

Features and applications:

  • Wide selection of FIB sources (Ga+, plasma ion, and laser) to cover wide range of applications for different battery materials (Li-ion, Li-metal, solid-state batteries) at multiple length scales
  • 2D cross-section and 3D characterization with Thermo Scientific Avizo Software for structural quantification, quality assessment, and failure analysis
  • Thermo Scientific Auto Slice & View 5 Software and Thermo Scientific AutoTEM 5 Software provide automation for 3D data collection and TEM sample preparation to improve efficiency in battery R&D and production
  • In situ detection of lithium distribution within the DualBeam via TOF-SIMS

Transmission electron microscopy for high-resolution analysis at the atomic scale

Transmission electron microscopy (TEM) provides high-resolution characterization at the sub-nanometer scale, delivering information to support the elucidation of behavior at the atomic level. Using TEM, scientists and engineers can delve deeper into the intricate details of material structures such as atomic arrangement and crystal structure to gain insights into the relationship between structure and functionality that are inaccessible with alternative techniques.

 

For battery applications, TEM techniques such as high-resolution imaging, electron diffraction, EDS, and EELS, can provide you valuable insights into the morphology, crystal structure, and chemical information of battery components. It is well-suited for nanoscale characterization of beam-sensitive materials commonly found in battery research, such as solid-electrolyte interphases (SEI). Resolving the SEI’s composition and structure is essential for understanding how lithium ions move in and out of the electrode, providing information on how the capacity retention drops over battery cycling. Such insights are crucial for developing next-gen batteries and gaining a mechanistic understanding of aging and failure mechanisms. Our TEM systems for the battery industry incorporate sample holders designed specifically for materials of interest. They also feature integrated workflows for the analysis of air-sensitive and beam-sensitive battery materials in their native electrochemical states.

2D and 3D elemental distribution of the SEI in nanosized Si electrode wires after different battery cycles. Acquired on a Talos TEM with Thermo Scientific Super-X™ EDS Detector under cryogenic conditions to preserve structural and chemical information. Sample courtesy of Dr. Chongmin Wang, Pacific Northwest National Laboratory.

Features and applications:

  • Fast, precise, quantitative, high-resolution characterization of microstructure, composition, and chemical state in battery materials
  • X-CFEG provides better, faster S/TEM and analytics, as well as much better energy resolution
  • Thermo Scientific Velox Software for fast, easy, multi-mode data acquisition and analysis
  • High-performance EDS under cryo condition for SEI characterization

X-ray photoelectron spectroscopy for quantitative surface chemistry analysis

X-ray photoelectron spectroscopy (XPS) is a surface analysis technique that provides quantitative elemental, electronic state, chemical state, and bonding information for the uppermost layers of a sample. For the battery industry, it is especially useful for studying surface phenomena, such as interface reactions, surface contamination, and notably, for elucidating the mechanisms associated with the formation of the SEI. For example, cathode and anode materials of Li-ion cells can be studied to confirm post-cycling changes in composition, to understand the changes in the chemistry of the electrode components, and to determine how the solid electrolyte interface (SEI) layer varies in depth as it develops. XPS has proved useful in studying surface pre-treatment of graphite electrode materials to significantly slow the irreversible consumption of material during battery charging.

Survey spectra from pristine cathode (blue) and cycled cathode (red) samples.

Our XPS instruments incorporate a variety of capabilities dedicated to battery research.

 

  • Effective detection of lithium in the battery materials, such as SEI characterization
  • Sample transfer from a glove box to the instrument without air exposure via vacuum transfer module
  • Ar cluster-ion depth profiling permits analysis of electrodes and separators without affecting chemistry
  • Sample heating, cooling, and electrical biasing possible in situ for various battery materials and system evaluation within XPS

Inert Gas Sample Transfer Workflow for the analysis of battery materials in their native state

Most battery materials, including lithium metal and salts, solid-state electrolytes, and cycled electrodes are air- and moisture-sensitive. Therefore, optimized sample preparation strategies are crucial to analyze such samples in their native electrochemical states and access accurate, representative insights.

 

IGST Workflow for nanoscale analysis using Thermo Scientific DualBeam and TEM systems.

The Thermo Scientific IGST (Inert Gas Sample Transfer) Workflow uses proprietary tools such as the Thermo Scientific CleanConnect Sample Transfer System to provide inert gas protection that preserves the integrity of delicate samples by avoiding contamination by either air or moisture. The CleanConnect System has multiple features designed for battery applications.

 

  • Sample integrity is preserved, resulting in high-end battery material characterization in its native state
  • Ergonomic and modular design of the CleanConnect System
  • In-house design of the CleanConnect System enables seamless connectivity and automatic integration with a variety of Thermo Scientific SEMs and DualBeams and the CleanMill Broad Ion Beam System
  • Compatibility with cryo-stage allows sample integrity while milling against heat damage

Li-metal is one of the most important anode materials for next-generation batteries. However, due to its intrinsic properties of air, moisture, and beam sensitivity, characterizing it via scanning transmission electron microscopy (S/TEM) analysis is one of the most critical, while challenging, tasks. The IGST Workflow enables high-resolution atomic-scale analysis on Li- metal samples. It allows you to focus on your research rather than worry about contaminating the sample.

LI-metal TEM lamella prepared via IGST workflow

For Research Use Only. Not for use in diagnostic procedures.