KR102278258B1 - method of inspection - Google Patents

Abstract

An inspection method for inspecting the surface electronic state of an electrode material for a lithium secondary battery or a solid electrolyte material under atmospheric pressure, wherein the surface electronic state of the electrode material for a lithium secondary battery from an intrinsic ionization potential of the electrode material for a lithium secondary battery or the solid electrolyte material Inspection method to check.

Description

method of inspection

The present invention relates to an inspection method for inspecting the surface electron state of a material for a lithium secondary battery.

This application claims priority based on the patent application 2018-066495 for which it applied to Japan on March 30, 2018, and uses the content here.

BACKGROUND Lithium secondary batteries have already been put to practical use as small power sources for mobile phone applications and notebook computers. Moreover, application is attempted also in a medium-sized or large-sized power supply, such as an automobile use and an electric power storage use. In order to improve and maintain the performance of a lithium secondary battery, various examinations are also made also about the method of test|inspecting the performance of the lithium secondary battery itself or its material.

For example, Patent Document 1 describes a secondary battery inspection method for inspecting an internal short circuit of the secondary battery.

Japanese Patent Application Laid-Open No. 2012-104276

BACKGROUND ART In lithium secondary batteries, powders of lithium composite oxides and non-oxides are used as electrode active materials and solid electrolytes. The surface of the lithium composite oxide deteriorates when exposed to the atmosphere. As an example of a deterioration phenomenon, a resistance layer may be formed on the surface by reacting with moisture in air|atmosphere. Generation|occurrence|production of such a deterioration phenomenon becomes a cause of performance deterioration of a lithium secondary battery. In addition, when the crystal structure is disturbed due to cation mixing or generation of lattice defects, the battery performance is significantly deteriorated.

Therefore, there is a demand for an inspection method that accurately predicts the performance of a material for a lithium secondary battery used as a raw material for a lithium secondary battery in a short time without performing a battery test.

The present invention has been made to solve the above problems, and in a short time, the surface electronic state such as the generation of a 10 nm thick surface resistance layer from the atomic layer level or the crystal structure is disturbed, which influences the performance of lithium secondary battery materials, The purpose of this is to provide a method for accurately inspecting. Thereby, the performance of the material for lithium secondary batteries used as a raw material of a lithium secondary battery can be accurately predicted in a short time, even if it does not conduct a battery test.

The present invention includes the following [1] to [9].

A first aspect of the present invention provides an inspection method described in [1].

[1] An inspection method for inspecting the surface electronic state of an electrode material for a lithium secondary battery or a solid electrolyte material under atmospheric pressure, wherein the electrode material for a lithium secondary battery from the inherent ionization potential of the electrode material for a lithium secondary battery or the solid electrolyte material or inspecting the surface electronic state of the solid electrolyte material.

The first aspect method preferably includes the following features.

[2] The inspection method according to [1], wherein the ionization potential is measured by an atmospheric ultraviolet light electron spectroscopy apparatus.

[3] The inspection step includes a measuring step of measuring the ionization potential of the electrode material for a lithium secondary battery or the solid electrolyte material immediately after exposure to the atmosphere using an ultraviolet photoelectron spectroscopy device in the atmosphere, and thereafter a measuring step of exposing the electrode material or the solid electrolyte material for a lithium secondary battery to the atmosphere again, and measuring the ionization potential of the material again exposed to the atmosphere using the apparatus; A judgment step of judging whether the measured ionization potential has increased than the ionization potential immediately after exposure to the atmosphere, and when it is judged that it has increased, deterioration is observed on the surface of the electrode material for a lithium secondary battery or the solid electrolyte material The inspection method according to [1] or [2], comprising a judgment step of judging.

Moreover, this invention includes the following aspect.

[4] The inspection method according to [3], wherein the measurement immediately after exposure to the atmosphere is performed between 0 minutes and 5 minutes or less after exposing the electrode material for a lithium secondary battery or solid electrolyte material to the atmosphere.

[5] preparing an electrode material or a solid electrolyte material for a lithium secondary battery as a first sample, and performing one or more measurements by changing the exposure time of the first sample to the air by one or more times, Obtaining a value of the above ionization potential, storing the value, preparing a second sample comprising a compound having the same chemical composition as the first sample, and measuring the ionization potential of the second sample In [1], comprising: comparing the stored value of the first sample with the measured value of the second sample; and determining the surface electronic state of the second sample from the result of the comparison described test method.

[6] STEM-ADF measurement of the electrode material for a lithium secondary battery or the solid electrolyte material exposed to the atmosphere and the ionization potential thereof is measured, and the electrode material for a lithium secondary battery or solid electrolyte material exposed to the atmosphere and comparing one or more results of the EELS measurement, and ascertaining a surface electronic state of the electrode material for a lithium secondary battery or a solid electrolyte material from the comparison result.

[7] comparing the value of the ionization potential of the first sample exposed to the atmosphere and the STEM-ADF measurement and the EELS measurement of the first sample exposed to the atmosphere; The inspection method according to [5], comprising the step of determining the surface electronic state of the sample.

[8] The result of measuring the ionization potential of the electrode material or the solid electrolyte material for a lithium secondary battery by exposing it to the atmosphere, and the discharge capacity by using the electrode material or the solid electrolyte material for the lithium secondary battery in the battery The inspection method according to [1], comprising the steps of comparing the measured measurement results, and determining the surface electronic state of the electrode material for a lithium secondary battery or the solid electrolyte material from the comparison result.

[9] The second sample is a separately stored material, and the step of comparing the stored value of the first sample with the measured value of the second sample determines whether the second sample can be used for manufacturing a battery , or the step of determining whether it is unusable, the inspection method according to [5].

ADVANTAGE OF THE INVENTION According to this invention, the method of accurately inspecting the surface electronic state closely related to the performance of the material for lithium secondary batteries used for a lithium secondary battery, or a solid electrolyte material in a short time can be provided.

1 is LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ It is a figure which shows the powder X-ray diffraction measurement result measured immediately after exposing particle|grains to the atmosphere and every predetermined time thereafter.
2 is LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ It is a figure which shows the measurement result of the ionization potential measured immediately after exposing a particle to the atmosphere, and every predetermined time thereafter.
3 is LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ A diagram showing the results of the EELS measurement measured after the particles were exposed to the atmosphere for 3 hours.
4 is LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ A diagram showing the results of STEM-ADF observation measured after the particles were exposed to the atmosphere for 3 hours.

Hereinafter, preferred examples for carrying out the present invention will be described in detail. The following description is given specifically for better understanding of the gist of the invention, and unless otherwise specified, does not limit the present invention. Within the scope of the present invention, it is also possible to change, add, and/or omit time, number, timing, number, amount, material, shape, position, kind, etc. as needed, unless there is a particular limitation.

<　Inspection method>

The present invention is an inspection method for inspecting the surface electronic state of an electrode material for a lithium secondary battery or a solid electrolyte material in the atmosphere.

The present invention measures the ionization potential of an electrode material for a lithium secondary battery or a solid electrolyte material. In the present invention, the ionization potential inherent to the electrode material for a lithium secondary battery or the solid electrolyte material, that is, the material itself, is measured. In addition, the intrinsic ionization potential may be, for example, an ionization potential under the condition that the time exposed to the atmosphere is very short.

According to the present invention, lithium secondary battery materials such as electrodes and electrolytes are not subjected to special pretreatment, etc., in a relatively short time under the atmosphere, for example, within 5 minutes per sample, can be inspected. In addition, in this invention, although lower atmospheric pressure may mean standard atmospheric pressure, the state which is not carrying out the pressure reduction or pressurization by a special apparatus may be meant. Under atmospheric conditions may mean that it is under atmospheric atmosphere.

It is preferable to measure an ionization potential measurement with the ultraviolet light electron spectroscopy apparatus in air|atmosphere.

In this embodiment, with the "electrode material for lithium secondary batteries", the positive electrode active material for lithium secondary batteries, and the negative electrode active material for lithium secondary batteries are mentioned. As a specific example, the lithium composite metal oxide which has lithium and 1 type of element selected from the group of cobalt, nickel, manganese, and aluminum as a main component is mentioned.

When a more specific example of a lithium composite metal oxide is given, lithium nickel cobalt aluminum composite oxide, lithium nickel manganese composite oxide, etc. are mentioned, for example.

In the present embodiment, the "solid electrolyte material" is a material used for the electrolyte material of an all-solid-state battery. Specific examples include a sulfide solid electrolyte, an oxide solid electrolyte, a lithium-containing sulfide, a lithium-containing metal oxide, a lithium-containing nitride, and a lithium phosphate.

Although the shape and size of the said electrode material or solid electrolyte material are not specifically limited, Particles and a lump may be sufficient.

«First embodiment»

In the inspection method of this embodiment, the ionization potential of the electrode material for lithium secondary batteries or the solid electrolyte material is measured using the ultraviolet photoelectron spectroscopy apparatus in air|atmosphere. For example, the ionization potential of the material immediately after exposure to the atmosphere is also measured in advance, and whether the measured ionization potential is increasing compared to the ionization potential immediately after exposure to the atmosphere is compared and judged. And when it increases, it determines with deterioration seen on the surface of the electrode material for lithium secondary batteries. In the present invention, the length of the exposure time can be arbitrarily set each time. For example, using one sample, exposure is performed continuously or intermittently, and evaluation is performed whenever predetermined time passes. Alternatively, one or more samples of the same type or different types may be prepared, and the conditions may be changed for evaluation. In addition, these data may be stored and used for comparison. For example, with respect to the product of a specific compound, you may measure and store the data of the ionization potential in the case where the length of exposure time differs for reference in advance in advance. Thereafter, when there is a product of the same kind of compound to determine whether there is no deterioration, the ionization potential of the product is measured and compared with the stored data.

For a specific example, an electrode material or a solid electrolyte material for a lithium secondary battery is prepared as a first sample, the material is subjected to one or more measurements by changing the exposure time to the air by one or more times, and one or more ionization You can get the value of the potential and store this value. You may measure the said measurement only immediately after exposure. Then, separately, prepare a second sample comprising a compound having the same chemical composition and/or other characteristics as the first sample, measure its ionization potential, and compare the stored value of the first sample and the second sample The measured values may be compared, and the surface electronic state of the second sample may be determined from the result.

And, in the ultraviolet photoelectron spectroscopy apparatus in the air, the sample is irradiated with ultraviolet rays while changing the energy of the ultraviolet rays. The range of energy of ultraviolet light used for measurement can be arbitrarily selected. The number of photoelectrons emitted from the material is measured with an open counter capable of electronic counting in the atmosphere. Thereby, the ionization potential can be measured in air|atmosphere.

In the present embodiment, immediately after exposure of the electrode material for a lithium secondary battery or the solid electrolyte material to the atmosphere is defined as 0 hours. And ionization potential measurement is performed every time arbitrarily set, for example, every 1 hour. The electrode material for a lithium secondary battery and the solid electrolyte material in front of the measurement can be stored so as not to come into contact with the atmosphere.

From the ionization potential of 0 hours, when 0.1 eV or more increases, it determines with the surface of the electrode material for lithium secondary batteries or the surface of a solid electrolyte material that deterioration was seen. In addition, immediately after exposure to air|atmosphere may be time selected arbitrarily. For example, it may take out in air|atmosphere, and 15 minutes from 0 minutes may be sufficient, 10 minutes from 0 minutes, 5 minutes from 0 minutes, or 3 minutes from 0 minutes may be sufficient.

By measuring the ionization potential, changes from an ideal structure, such as whether or not a resistance layer is formed on the surface of the lithium secondary battery material, in particular, changes in the surface electronic state closely related to battery characteristics are determined in a short time can do.

According to the present invention, for example, a separately stored material is compared with data of the ionization potential of a material of the same type that has been previously measured and stored to determine whether the stored material can be used for manufacturing a battery; Or it can be easily determined whether it is usable.

The result of the obtained ionization potential is judged by combining the result in the second embodiment described below, the result of STEM-ADF measurement or EELS measurement, and the result of the discharge capacity obtained by actually using the battery material for the battery. may be done

«Second embodiment»

When this embodiment synthesize|combines the electrode material for lithium secondary batteries, it measures the ionization potential of the synthesize|combined electrode material for lithium secondary batteries. And it is compared and judged whether the measured ionization potential has increased more than that of the standard electrode material for lithium secondary batteries of the same composition measured separately. And when it increases, it is an inspection method which determines with what kind of change generation|occurrence|production, for example, whether or not cation mixing is occurring, etc. that the surface of the electrode material for lithium secondary batteries was disturbed in crystal structure was seen. For example, while using the same material or material composition, the ionization potential values of a plurality of battery materials obtained by changing the conditions of the manufacturing conditions and manufacturing methods are measured and compared. Further, as in the first implementation, the obtained material may be evaluated for an ionization potential value according to a difference in exposure time to the atmosphere, and may be used for judgment. You may judge by combining the result of STEM-ADF measurement and EELS measurement, the result of the discharge capacity obtained by actually using a battery material for a battery, etc.

≪STEM-ADF, EELS measurement≫

You may use STEM-ADF measurement and EELS measurement in combination with the measurement of 1st Embodiment or 2nd Embodiment. You may implement the STEM-ADF(Annular Dark Field Scanning Transmission Electron Microscope) measuring method as follows. The electrode material for a lithium secondary battery is processed into a thin film for cross section measurement by CP (cross section polisher), FIB (focused ion beam), or the like. Then, an electron beam is applied so as to pass through the cross section of the sample, scattered electrons are measured, and the intensity is displayed as a phase. In addition, EELS measurement is a method of measuring the energy lost by electrons passing through the same sample plane by interaction with atoms.

In the image obtained by the method described above, when no lattice fringes corresponding to the crystal structure are observed on the surface of the electrode material for a lithium secondary battery or the solid electrolyte material, it can be determined that a resistance layer is formed.

By combining the measurement values obtained by the first and second embodiments and the surface observation results by either or both of the STEM-ADF measurement method and the EELS measurement, the outermost surface layer that is difficult to detect in X-ray diffraction measurement The electronic state change in , from the result of the ionization potential measurement, can be better predicted. By collecting and accumulating such data, the surface electronic state of the lithium secondary battery material can be inspected in detail based on a short-time inspection result.

[Example]

Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to the following Example.

(Example 1): LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ Predicting performance degradation due to the generation of a resistive layer on the particle surface

_{LiNi 0} synthesized by reacting a precursor synthesized by an air-core method with lithium hydroxide _{. 82} Co _{0 . 15} Al _{0 . 03} O ₂ The particles were exposed to the atmosphere. Immediately after this and every predetermined time thereafter, powder X-ray diffraction measurement and ionization potential measurement were performed.

The change in the peak position and the relative intensity in the obtained X-ray diffraction result, and the change in the ionization potential were investigated.

Ionization Potential Measurement

The change in the ionization potential was measured using an atmospheric photoelectron spectrometer (manufactured by Riken Instruments Co., Ltd., AC-3, Japan). The atmospheric photoelectron spectroscopy device is an atmospheric ultraviolet photoelectron spectroscopy device. Specifically, LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ About 100 mg of a powder sample of particles was prepared on a dedicated sample stand, and was measured in an energy range of 4.2-7.0 eV. Until just before the measurement, the sample was stored in an argon atmosphere with controlled dew point and in a pouch filled with dry argon gas. Samples were exposed to the atmosphere only during exposure treatment or measurement.

The time applied to the measurement of one sample was within 5 minutes. With respect to the obtained results, energy is plotted on the horizontal axis, and the square root of the normalized photoelectron yield is plotted on the vertical axis. It was estimated as an ionization potential from the intersection of the external insertion straight line obtained by the least squares method and the ground level. The ionization potential obtained as a result of the ionization potential of the sample immediately after exposure and after 3 hours is shown in FIG. 2 as the horizontal axis (unit: eV), and the normalized intensity as the vertical axis (in FIG. 2, described as “Count (%)”) do.

Powder X-ray diffraction measurement

In general, LiNi _{0 . 82} Co _{0 . 15} Al _{0 . In} the lithium nickel-containing composite oxide represented by 03 O ₂ , in the layered rock salt crystal structure, the (003) plane obtained from powder X-ray diffraction using Cu-Kα rays as an X-ray source and the ratio of the diffraction line peak intensities attributed to the (104) plane is 1.2 or more.

From this ratio of peak intensities, the disturbance of the crystal structure was judged. When cation mixing is occurring, that is, when the crystal structure approaches from the layered rock salt type to the rock salt type, the X-ray diffraction intensity attributable to the (003) plane becomes small. Therefore, it means that the layered rock salt structure with few disturbances is, so that this ratio of this peak intensity is large.

1 , LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ The powder X-ray diffraction measurement results, which were measured by exposing the particles to the atmosphere immediately after exposure, and thereafter, every hour thereafter for up to 5 hours, are shown. As is also apparent from Fig. 1, the lines showing the results overlap, and no change was observed in the positions of the diffraction lines or in the ratio of the peak intensities of the diffraction lines attributed to the (003) plane and the (104) plane. No change could be detected in powder X-ray diffraction measurements.

2 , LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ The measurement results of the change in the ionization potential, measured immediately after the particles were exposed to the atmosphere, and every predetermined time thereafter are shown.

As is also apparent from Fig. 2, it can be seen that the ionization potential significantly increased from the intersection of the external interpolation straight line obtained by the least squares method and the ground level after 3 hours had elapsed after exposure to the atmosphere.

3 , LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ The results of the EELS measurements, which were measured after the particles were exposed to the atmosphere for 3 hours, are shown. 4 , LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ The results of STEM-ADF observation, which were measured after the particles were exposed to the atmosphere for 3 hours, are shown. In these, the measurement time of 2 days or more was required for the measurement of one sample. From the STEM-ADF observation photograph, the formation of a layer having a shape different from that of a lattice stripe was seen, suggesting that the surface layer had a different shape. In addition, the EELS spectrum shows a shift of the peak derived from Ni in a layer with a thickness of about 10 nm from the surface. This suggests generation of a rock salt type (resistance layer) of the surface layer. These results correspond to the measurement results of the ionization potential.

_{The LiNi 0} after no air exposure and 3 hours of air exposure _{. 82} Co _{0 . 15} Al _{0 . 03} O ₂ An R2032-type half cell using particles as an electrode active material was produced.

After the open circuit voltage is stabilized, the current density for the positive electrode at 25° C. is 10 mAh/g with respect to the weight of the positive electrode active material, and charging is performed until it reaches 4.3 V, and thereafter until it reaches 3.0 V. A charge-discharge test was performed to measure the discharge capacity when discharged, and the initial discharge capacity was determined.

As a result, LiNi _{0 of unexposed atmosphere. 82} Co _{0 . 15} Al _{0 . 03} O ₂ In a battery using particles as a positive electrode active material, an initial capacity of 200 mAh/g was obtained. In contrast, LiNi _{0 . 82} Co _{0 . 15} Al _{0 . 03} O ₂ In the case of a battery using particles as a positive electrode active material, it was found that it decreased to 180 mAh/g or less. Although all of the active materials had a lithium occupancy rate of about 98%, there was a difference in initial discharge capacity. The result is thought to depend on the difference in the presence or absence of the resistance layer formed on the particle|grain surface.

As described above, it was found that the performance degradation predicted from STEM-ADF observation and EELS measurement required for measurement for two days or more could be predicted within 5 minutes of measurement time by ionization potential measurement.

(Example 2): Prediction of performance degradation by cation mixing on the surface of LiCoO2 single crystal grains

_{The ionization potential of eight LiCoO 2} single crystal grains synthesized by different methods was measured using an atmospheric photoelectron spectrometer (manufactured by Riken Instruments Co., Ltd., AC-3, Japan) in the air. About 100 mg of a powder sample of the isolated LiCoO ₂ single crystal grains was prepared on a dedicated sample stage, and it was measured in an energy range of 4.2-7.0 eV. Until immediately before measurement, the sample was stored in an argon atmosphere with controlled dew point and in a pouch filled with dry argon gas. It was exposed to air only during the measurement. The time applied to the measurement of one sample was within 5 minutes. In the determination method of this invention, determination can be performed according to the high and low of the obtained ionization potential value.

With respect to the obtained results, energy is plotted on the horizontal axis, and the square root of the normalized photoelectron yield is plotted on the vertical axis. It was estimated as an ionization potential from the intersection of the external insertion straight line obtained by the least squares method, and the ground level.

Table 1 shows the ionization potential and initial discharge capacity for eight samples.

Specifically, _{eight R2032-type half cells each using LiCoO 2} single crystal grains as an electrode active material were prepared, and after the open circuit voltage was stabilized for these, the open circuit voltage was stabilized at 25° C. at 0.5 C until 4.2. The charge-discharge test which measures the discharge capacity at the time of charging and discharging at 10C until it becomes 2.8V after that was done. Table 1 shows the initial discharge capacity and the ionization potential corresponding to the LiCoO2 particles.

The eight samples had the same particle shape, composition, and X-ray diffraction pattern as in the experiment of Example 1. _{Nevertheless, only a secondary battery using LiCoO 2} single crystal grains having an ionization potential of 5.75 eV or less for the positive electrode as a positive electrode active material, but 130 mAh/g or more exhibits good initial discharge capacity (Samples 1, 3, 5, 7, 8). _{Cationic mixing on the surface of the LiCoO 2} crystal grains is considered to be a factor in the difference in these physical properties. From the result, it turns out that the superiority of this invention is shown remarkably.

As described above, according to the present invention, it is possible to provide a method for accurately inspecting the performance of an electrode material for a lithium secondary battery used as a raw material for a lithium secondary battery in a short time.

Claims (9)

An inspection method for inspecting the surface electron state of an electrode material for a lithium secondary battery or a solid electrolyte material under atmospheric pressure, comprising:
An inspection method comprising an inspection step of inspecting a surface electronic state of an electrode material for a lithium secondary battery or a solid electrolyte material from an intrinsic ionization potential of the electrode material for a lithium secondary battery or the solid electrolyte material,
The inspection step is
a measuring step of measuring an ionization potential of an electrode material for a lithium secondary battery or a solid electrolyte material immediately after exposure to the atmosphere, using an atmospheric ultraviolet light electron spectroscopy apparatus;
thereafter, exposing the electrode material or the solid electrolyte material for a lithium secondary battery to the atmosphere again, and measuring the ionization potential of the material exposed to the atmosphere again using the apparatus;
a judging step of determining whether the ionization potential measured for the material again exposed to the atmosphere is increased than the ionization potential immediately after exposure to the atmosphere; and
a judgment step of judging that deterioration is seen on the surface of the electrode material for a lithium secondary battery or the solid electrolyte material when it is judged that there is an increase;
including,
The measurement immediately after exposure to the atmosphere is performed between 0 minutes and more and 5 minutes or less after exposing the electrode material for a lithium secondary battery or solid electrolyte material to the atmosphere,
method of inspection. According to claim 1,
preparing an electrode material or a solid electrolyte material for a lithium secondary battery as a first sample;
changing the exposure time of the first sample to the air by one or more times, performing one or more measurements, and obtaining one or more values of ionization potentials;
storing the value;
preparing a second sample comprising a compound having the same chemical composition as the first sample;
measuring an ionization potential of the second sample;
comparing the stored value of the first sample with the measured value of the second sample; and
determining a surface electronic state of the second sample from the result of the comparison;
Further comprising, an inspection method. According to claim 1,
A measurement result of measuring the ionization potential of the electrode material for a lithium secondary battery or the solid electrolyte material exposed to the atmosphere, STEM-ADF measurement of the electrode material for a lithium secondary battery or the solid electrolyte material exposed to the atmosphere, and comparing results of one or more of the EELS measurements; and
From the comparison result, determining the surface electronic state of the electrode material for the lithium secondary battery or the solid electrolyte material; further comprising, the inspection method. 3. The method of claim 2,
comparing the value of the ionization potential of the first sample exposed to the atmosphere with a result of at least one of a STEM-ADF measurement and an EELS measurement of the first sample exposed to the atmosphere; and
The method further comprising: determining a surface electronic state of the second sample from the comparison result. According to claim 1,
The result of measuring the ionization potential of the electrode material or the solid electrolyte material for a lithium secondary battery by exposing it to the atmosphere, and the discharge capacity by using the electrode material for the lithium secondary battery or the solid electrolyte material in the battery comparing the measurement results; and
From the comparison result, determining the surface electronic state of the electrode material for the lithium secondary battery or the solid electrolyte material; further comprising, an inspection method. 3. The method of claim 2,
The second sample is a material stored separately,
Comparing the stored value of the first sample with the measured value of the second sample comprises determining whether the second sample can be used for manufacturing a battery or not. delete delete delete

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