一般財団法人材料科学技術振興財団　MST List of Products and Services

The characteristics and reliability of lithium-ion secondary batteries are greatly influenced by materials, among which the impact of the electrolyte is said to be significant. Commercial products in various shapes, such as cylindrical and laminated types, can have their electrolytes extracted using appropriate methods, allowing for the identification of organic solvents and additives. The following case involves extracts from prismatic batteries, confirming the use of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) as organic solvents, and fluoroethylene carbonate (FEC) as an additive.

The separator, which is a key component material of batteries, influences the characteristics and safety of the battery due to its porosity, shape, and other factors. Currently, mainstream polymer materials such as polyethylene (PE), polypropylene (PP), or their composite materials have low softening points, with PE being around 125°C and PP around 155°C. We will introduce a case where the structure of a PP separator with a low softening point was observed, and cooling was performed during cross-section processing to suppress degradation for evaluation.

High-resolution HAADF-STEM images reflect the atomic arrangement of crystals, and by simulating STEM images corresponding to various crystal orientations, they help in accurately understanding the relative orientations between crystal grains and the observed images in polycrystalline materials. This document presents a case where STEM images were simulated from the crystal orientation information obtained by the EBSD method for the crystal grains in a polycrystalline neodymium magnet, and compares them with actual high-resolution HAADF-STEM images.

This document presents a case study of Rietveld analysis applied to the powder X-ray diffraction data of Li(Ni, Mn, Co)O2, which is used as a positive electrode active material in lithium-ion secondary batteries. By seeking a crystal structure model that reproduces the measured powder X-ray diffraction data through simulation, it is possible to precisely calculate crystal structure parameters such as lattice constants, site occupancy rates, and the proportion of cation mixing, which can then be used to discuss the material properties.

The electrolyte used in lithium-ion batteries is generally composed of a solvent and an electrolyte salt, and is considered a homogeneous system on a macroscopic scale. However, from a microscopic perspective, phenomena such as solvation occur. Understanding the local structure of lithium-ion solvation and the reactions that occur when inserting into the positive and negative electrodes is important for the design of high-performance battery materials. This document presents a case study that evaluates the microscopic structure of lithium-ion solvation in the electrolyte of lithium-ion batteries using molecular dynamics simulations.

The segregation of components and the formation of films on the surface of the positive electrode of lithium-ion secondary batteries are factors that influence the electric capacity. We will introduce a case study on Li(NiCoMn)O2 (NCM), which is used as a positive electrode, where micro-region mapping was conducted using AES, and qualitative analysis of organic components (binder) and active material surface films was performed using XPS and TOF-SIMS. These methods allow for analysis with a series of treatments conducted under an Ar atmosphere, which helps to suppress the alteration of the sample.

In lithium-ion secondary batteries, Li(NiCoMn)O2 (NCM) used as the positive electrode can achieve higher capacity by increasing the Ni ratio, and it also excels in high-temperature storage, making it suitable for mass production for automotive applications. On the other hand, cation mixing, where Ni ions occupy Li sites, is considered one of the factors contributing to the degradation of secondary batteries. This presentation will introduce a case where the metal content of the positive electrode active material was evaluated using ICP-MS, the crystal structure was assessed using XRD, and the results were used to perform Rietveld analysis to evaluate the proportion of cation mixing.

Next-generation all-solid-state batteries, which are lithium-ion batteries, are expected to have high safety, high energy density, high output, and a wide operating temperature range. In recent years, research and development aimed at practical application has been actively conducted, but there are various development challenges. At MST, we propose evaluation content suitable for solving development challenges based on comprehensive analysis and evaluation of structure, composition, and electrical properties. This document introduces specific examples of development challenges for all-solid-state batteries, their evaluation content, and representative evaluation methods for each component.

The binder for lithium-ion secondary batteries not only serves as an adhesive between active materials but also needs to be insoluble in the electrolyte. Therefore, the selection of suitable materials for both the positive and negative electrodes is crucial. This document presents cases where the components of the binders used in each electrode sheet were identified by measuring the positive electrode binder using TOF-SIMS and the negative electrode binder using GC/MS, and then comparing the results with a materials library database.

In the electrolyte of lithium-ion secondary batteries, a combination of high dielectric constant solvents and low viscosity solvents is used to improve electrical conductivity. Additionally, additives and electrolytes (supporting salts) not only facilitate the transport of Li ions but also have the function of forming a film on the electrode surface, requiring various performance characteristics. This paper presents examples of qualitative and quantitative analysis of various components such as solvents, electrolytes, and additives by evaluating the electrolyte itself using ICP-MS, volatile components during electrolyte heating using GC/MS, and the dry residue of the electrolyte using TOF-SIMS.

The separator in lithium-ion secondary batteries not only serves the role of isolating the positive and negative electrodes to prevent internal short circuits, but in automotive batteries, it is also required to have heat resistance to prevent a decrease in strength or melting even in high-temperature environments. This report introduces a case study on separators used in overseas automotive batteries, where heat resistance and thermal decomposition behavior were investigated using TG-DTA, and structural and compositional evaluations were conducted using SEM-EDX, FT-IR, XPS, TOF-SIMS, and XRD. It was found that the separator used in the battery consists of a porous polyethylene and a layered structure of polygonal AlO(OH) aimed at heat resistance.

The charge and discharge characteristics of lithium-ion secondary batteries are influenced by electronic conductivity. I will introduce a case where the decreased conductivity of active materials, due to degradation or blockage of conduction paths, was visualized as a resistance value distribution using SSRM. By comparing the results obtained from SSRM with the elemental distribution of Li and other elements measured by TOF-SIMS, it is possible to confirm the correlation between resistance values and elemental distribution. Additionally, it is feasible to classify conductive additives and binders based on resistance values, perform statistical processing, and quantify the mixing degree for each material.

This article introduces a case study evaluating the surface morphology, cross-sectional structure, components, composition, crystal structure, and resistance value distribution of Li(NiCoMn)O2 (NCM), which is used as a positive electrode in lithium-ion secondary batteries. Based on a comprehensive evaluation of structure, composition, and electrical properties, MST proposes assessments suitable for solving development challenges aimed at improving characteristics and enhancing reliability.

We have launched a new service using XPS/HAXPES starting in June! For increasingly complex materials and fine structure samples, we can evaluate the composition and chemical bonding states from the surface to the interior of the material (up to ~30nm) at the same location and in a non-destructive manner. - Depending on the elements of interest and the analysis area and depth, we can select the appropriate X-ray source (Al Kα/Mg Kα/Ga Kα/Cr Kα) to achieve evaluation under suitable measurement conditions. - Non-exposure measurements to the atmosphere, Ar monomer/GCIB sputter etching, and heating pretreatment can be combined. - It is possible to evaluate the electronic states of semiconductor samples using UPS/LEIPS (ionization potential/electron affinity/band gap).

Our organization has established a system that suppresses atmospheric exposure through atmosphere control, and further cools the samples for processing, observation, and analysis. We can produce TEM thin samples while maintaining the original structure of the specimen, allowing for observation and analysis. Even with unstable materials, we can perform thinning processing while cooling, and by maintaining a vacuum during the transfer between processing and observation devices, we enable cross-sectional TEM/SEM observation that minimizes atmospheric exposure and thermal alteration. 【Measurement and Processing Methods】 ■ [(S)TEM] Scanning Transmission Electron Microscopy ■ Processing under atmosphere control ■ Cryo-processing *For more details, please download the PDF or feel free to contact us.

We offer particle size analysis of Au nanoparticles using small-angle X-ray scattering (SAXS) method. Metal nanoparticles are known to exhibit unique properties not found in bulk metals. Due to their high catalytic activity and optical properties such as surface plasmon resonance, they are used in applications like fuel cell electrode catalysts and biosensors. To control these properties, it is necessary to understand their structure and composition. By using TEM and SAXS complementarily, it is possible to conduct reliable particle size analysis. [Measurement and Processing Methods] ■ [(S)TEM] Scanning Transmission Electron Microscopy ■ [SAXS] Small-Angle X-ray Scattering *For more details, please download the PDF or feel free to contact us.

Our company conducts local area evaluation of positive electrode active materials for secondary batteries (C0614). It is known that in lithium-ion secondary batteries, the crystal structure of the active material surface and the valence of metal elements change due to ion extraction and insertion during charge and discharge, as well as degradation. In a case where TEM was used for local area evaluation to assess composition, crystal structure, and chemical state, it was found through EDX that AlOx is coated on the outermost layer. Additionally, electron diffraction and EELS revealed that the crystal structure and valence differ between the surface and the interior of the active material. [Measurement and Processing Methods] ■ [(S)TEM] Scanning Transmission Electron Microscopy ■ [TEM-EDX] Energy Dispersive X-ray Spectroscopy (TEM) ■ [TEM-EELS] Electron Energy Loss Spectroscopy *For more details, please download the PDF or feel free to contact us.

Our organization offers structural evaluation of lithium-ion secondary battery anode materials. The structural state of the anode materials, such as the dispersion of active substances and porosity, affects performance. In this case, we observed the internal structure of the anode material using X-ray CT, which allows for non-destructive and high-resolution measurement of the three-dimensional structure. By analyzing the results obtained from X-ray CT, it is also possible to detect foreign substances within the electrode material and evaluate the porosity of the active substance layer. [Measurement Method / Processing Method] ■ X-ray CT Method *For more details, please download the PDF or feel free to contact us.

Our organization provides the energy profile of the Li-ion insertion and extraction process in LIB anodes/electrolytes using the ESM-RISM method. During the charge and discharge processes of lithium-ion secondary batteries (LIB), various phenomena occur near the interface with the electrolyte and the anode, including the formation of solvation, desolvation, the formation of the electric double layer, and the insertion and extraction of Li ions. This document introduces a case study that evaluates the energy profile and solvation structure during the Li-ion insertion and extraction process from graphite anodes using the hybrid ESM-RISM method, which combines Effective Screening Medium (ESM) and Reference Interaction Site Model (RISM) through simulation. [Measurement and Processing Methods] ■ Computational Science, AI, Data Analysis *For more details, please download the PDF or feel free to contact us.

Our organization conducts evaluations of the bonding state of cathodes in secondary batteries. X-ray photoelectron spectroscopy (XPS), which is one of the methods for analyzing surface states, is suitable for evaluating binders and conductive additives due to its shallow detection depth (approximately 10 nm). Hard X-ray photoelectron spectroscopy (HAXPES), which uses hard X-rays (Ga rays) for excitation, allows us to obtain information about active materials buried under binders without causing damage, thanks to its deeper detection depth. 【Measurement and Processing Methods】 ■ [XPS] X-ray Photoelectron Spectroscopy ■ [HAXPES] Hard X-ray Photoelectron Spectroscopy ■ Processing under controlled atmosphere *For more details, please download the PDF or feel free to contact us.

Our organization conducts analyses of the thermal decomposition reactions of ionic liquids using quantum chemical calculations. Since ionic liquids are often used at high temperatures for extended periods, understanding their reactivity, such as thermal decomposition, is essential. We will introduce examples of evaluating the likelihood of thermal decomposition reactions of ionic liquids through quantum chemical calculations. 【Measurement Methods and Processing Methods】 ■Computational Science, AI, Data Analysis *For more details, please download the PDF or feel free to contact us.