JPH1054809A - Method for measuring x-ray absorbing fine structure of battery material and measuring cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform charging and discharging of active material in a tightly closed cell and to perform detailed measurement for the local crystal structure for every active material having the different charging and discharging quantity and the structure change accompanied by the charging and discharging. SOLUTION: A negative pole plate 3 and a positive pole plate 4 are bonded to each other in an airtight pattern through an insulating O ring 5. A cell main body 2, in which a containing part 12 of electrolyte solution 11 is formed, is provided in a space surrounded by the respective plates 3 and 4 and the O ring 5. An x-ray transmitting hole 13, which is communicated to the containing part 12, is formed at the positive pole par plate 4. The positive pole material of battery material is arranged in an airtight state under the state, in which the plate 4 is electrically conducted, in the transmitting hole 13. An X-ray transmitting hole 19, which is communicated to the containing part 12, is formed in the negative pole plate 3. A conducting foil is arranged in the transmitting hole 19 under the state, in which the plate 3 is electrically conducted. Escape holes with bottoms 26 and 27, by which the electrolyte solution 11 intruded into the respective through holes 13 and 19 are made to flow down and the electrolyte solution 11 is discharged through the respective through holes 13 and 19 when the cell main body 2 is arranged in the different up and down directions, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for measuring the structure of a battery material, and more particularly to a method for measuring an X-ray absorption fine structure (XAFS) and a cell for the measurement.

[0002]

2. Description of the Related Art First, a general X-ray absorption fine structure (XA
The measurement of FS) will be described. Light such as IR and UV is absorbed by the substance, but X-rays are also absorbed by the substance without exception, and the energy of the absorbed amount is converted into photoelectrons, fluorescent X-rays,
And converted to heat. At this time, part of the photoelectron wave generated by the absorption of X-rays is reflected as structural information on the amount of X-ray absorption due to scattering and interference by a plurality of atoms. That is, by monitoring the amount of X-ray absorption, information on the interatomic structure can be obtained.

When a substance is placed on an X-ray beam line, the intensity of the X-ray (incident X-ray: Io) irradiated to the substance and the intensity of the X-ray (transmission X-ray: It) passing through the substance are determined. The X-ray absorption amount (X-ray absorption coefficient) of the substance is calculated.

When the X-ray absorption spectrum is measured while changing the X-ray energy (wavelength) while monitoring the increase and decrease of the X-ray absorption coefficient, a sharp rise (absorption edge) of the X-ray absorption coefficient is observed at a certain energy position. You. Since the energy position at the absorption edge is unique to the element, if structural information can be extracted in the energy region near the absorption edge, it means that the information is unique to the element (element of interest).

When an X-ray absorption spectrum is measured with sufficient accuracy in the energy region near the absorption edge of a certain element of interest, a large structural vibration accompanied by attenuation is observed in the energy region of several tens eV from the absorption edge. This is converted to a structure near the X-ray absorption edge (XANES: X-Ray absorption near edge structu).
re), which mainly contains information related to the electronic state and three-dimensional structure of the element of interest.

[0006] In the energy region of several hundred eV on the higher energy side than XANES, fine structural vibration accompanied by similar attenuation is observed. This is called X-ray absorption fine structure (EXAFS: Extended X-Ray absorption fine s).
It contains information about the local structure (interatomic distance and coordination number) near the element of interest.

On the other hand, when the EXAFS spectrum extracted from the X-ray absorption spectrum is subjected to a Fourier transform in an appropriate region, a radial distribution function is obtained. This function is a one-dimensional distribution of electron density centered on the element of interest. Some atoms are located at the distance where the local maximum is shown, and the intensity (area) is proportional to the electron density of the located atom. ing. Therefore, structural information on the element of interest can be obtained by numerically examining the radial distribution function.

In recent years, the above-mentioned XANES and EX
AFS is generally called XAFS. That is,
XAFS is a technique for extracting fine structural vibrations (XAFS vibrations) from an X-ray absorption spectrum measured with high precision, and for embodying latent structural information therein by a calculation technique.

In order to search for a high-performance active material in, for example, a lithium secondary battery, the local crystal structure of each active material having a different charge / discharge amount and details of the structural change due to charge / discharge are measured. It will be an effective guideline to clarify this. To make such a measurement with XAFS,
For example, X-ray transmitting windows are provided concentrically on both walls of a sealed housing, and an active material charged and discharged to a predetermined charge / discharge amount is arranged in the housing, and X-rays are applied to the active material.
A method of transmitting a line is conceivable.

[0010]

However, in such a measurement method using XAFS, when the active material is taken out from the sealed type cell for charge / discharge and moved into the cell for XAFS measurement, careless contact with air occurs. For example, the physical properties of the active material may change, and as a result, accurate measurement may not be performed.

In addition, it is necessary to perform charging and discharging of the active material in another place, and since it is necessary to prepare various kinds of active materials having different charging and discharging amounts, there is a disadvantage that the measurement is troublesome. .

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is possible to charge and discharge an active material in a sealed cell and to locally charge and discharge each active material having a different charge and discharge amount. An object of the present invention is to provide a method for measuring an X-ray absorption fine structure of a battery material and a cell for the measurement, which can easily and accurately measure a crystal structure and details of a structural change due to charge and discharge.

[0013]

In order to achieve the above object, a method for measuring an X-ray absorption fine structure of a battery material according to the present invention is directed to a method for measuring a fine structure of a positive electrode plate and a negative electrode plate via an annular insulating seal member. The positive electrode and the negative electrode are hermetically bonded to each other to form an electrolyte solution accommodating portion in a space surrounded by the insulating and sealing members, and the accommodating portion is accommodated in one of the positive electrode plate and the negative electrode plate. A first X-ray transmitting hole communicating with the portion, and the first X-ray transmitting hole is hermetically disposed in a state in which the active material of the battery material is electrically connected to the plate; Forming a second X-ray transmission hole communicating with the accommodation portion in the second portion;
An X-ray absorption fine structure measurement cell in which a foil is air-tightly arranged in the X-ray transmission hole is prepared, and in a state where the electrolyte accommodated in the accommodation section has entered the first and second X-ray transmission holes. An electric current is applied to the positive and negative plates to charge and discharge the active material, and then the first and second X-ray transmission electrodes are discharged in a state where the electrolyte is discharged from the first and second X-ray transmission holes. The structure of the active material is measured by transmitting X-rays through the holes.

According to a second aspect of the present invention, there is provided a cell for measuring an X-ray absorption fine structure of a battery material, wherein a positive electrode plate and a negative electrode plate are hermetically bonded to each other via an annular insulating sealing member, and the positive electrode plate and the negative electrode plate are connected to each other. A first X-ray including a cell main body having an electrolyte solution accommodating portion formed in a space surrounded by the insulating sealing member and communicating with the accommodating portion on one of the positive electrode plate and the negative electrode plate; The second X-ray transmission hole is formed, and the first X-ray transmission hole is hermetically disposed in a state where the active material of the battery material is electrically connected to the plate, and the second X-ray transmission hole communicates with the receiving portion. Forming an X-ray transmitting hole, and placing a foil in the second X-ray transmitting hole in an airtight manner. Further, when the orientation of the cell body is changed, the first and second X-ray transmitting holes are formed. The first and second X-ray transmission holes are filled with the infiltrated electrolyte. Characterized by flowing on the side et spaced from the first and second X-ray transmission hole providing the relief portion for discharging the electrolyte.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a front view of a cell for measuring an X-ray absorption fine structure of a battery material according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line II-II of FIG.
2 is a partially detailed view of FIG. 2, and FIG. 4 is an explanatory sectional view for explaining a method for measuring the X-ray absorption fine structure of the battery material.

1 and 2, reference numeral 1 denotes a cell for measuring an X-ray absorption fine structure (hereinafter abbreviated as a cell for measuring XAFS). The cell 1 for measuring XAFS is a cell body 2.
Is provided. The cell body 2 includes a square negative electrode plate 3 made of, for example, stainless steel, a square positive plate 4 made of, for example, stainless steel, and a negative electrode plate 3 that are arranged facing the negative electrode plate 3 at a predetermined interval. An O-ring (insulating sealing member) 5 is interposed between the positive electrode plate 4 and the positive electrode plate 4. PFA on O-ring 5
(Ethylene tetrafluoride / perfluoroalkyl vinyl ether copolymer) and is disposed substantially concentrically with the centers of the negative electrode plate 3 and the positive electrode plate 4. In this embodiment, a circular O-ring is used as the insulating seal member. However, the present invention is not limited to this, and a rectangular or other shape may be used.

A plurality of bolt insertion holes 6 are formed at a radially outer position of the O-ring 5 of the positive electrode plate 4 at equal intervals in a circumferential direction, and an insulating sleeve 7 made of phenol resin or the like is formed in the bolt insertion holes 6. It is inserted. The head of the bolt 9 is in contact with the flange 8 of the insulating sleeve 7. A plurality of screw holes 10 corresponding to the bolt insertion holes 6 are formed at equal intervals in the circumferential direction on the radially outer side of the O-ring 5 of the negative electrode plate 3. By inserting a bolt 9 into the hole of the insulating sleeve 7 from the side of the positive electrode plate 4 and tightening it into the screw hole 10, the negative electrode plate 3 and the positive electrode plate 4 are air-tightly joined to each other via the O-ring 5. An accommodating portion 12 for the electrolytic solution 11 is formed in a circular space surrounded by the plates 4 and 3 of the negative electrode and the O-ring 5.

A first X-ray transmission hole 13 communicating with the housing 12 is formed in the positive electrode plate 4 at a position eccentric below the center of the housing 12. As shown in FIG. 3, the outer end of the first X-ray transmission hole 13 is made of, for example, LiNi.
A metal foil 15 such as aluminum having a positive electrode active material 14 of a battery material such as O ₂ adhered to one surface thereof has the first positive electrode active material 14 facing inward (toward the first X-ray transmitting hole 13). Are arranged so as to cover the X-ray transmission holes 13. Metal foil 1
5 is in contact with the outer surface of the positive electrode plate 4, whereby the positive electrode active material 14 is electrically connected to the positive electrode plate 4 via the metal foil 15.

An O-ring 16 is arranged on the outer periphery of the metal foil 15 of the positive electrode plate 4, and the O-ring 16 and the metal foil 15 are covered from the outside with, for example, a polyimide film 16a. Outside the polyimide film 16a, a circular member 17 in which a hole 17a having the same diameter as the first X-ray transmission hole 13 is formed at the center is arranged. Circular member 17
Are fixed to the positive electrode plate 4 by bolts 18 in a detachable manner with the holes 17a aligned with the first X-ray transmitting holes 13. A plurality of bolts 18 are arranged at regular intervals in the circumferential direction at a position radially outside the O-ring 16,
Thus, the positive electrode active material 14 is arranged in the first X-ray transmission hole 13 in an airtight manner.

A second X-ray transmission hole 19 communicating with the housing 12 is formed in the negative electrode plate 3 so as to be concentric with the first X-ray transmission hole 13 and have the same diameter. As shown in FIG. 3, for example, a metal foil such as lithium, a metal foil coated with a negative electrode active material, a foil made of a conductive material other than a metal, or the like is provided on the outer end of the second X-ray transmission hole 19. The conductive foil 20 is arranged so as to cover the second X-ray transmission hole 19. The peripheral portion of the conductive foil 20 is in contact with the outer surface of the negative electrode plate 3, whereby the conductive foil 20 is electrically connected to the negative electrode plate 3. In this embodiment, the conductive foil 20 is used. However, the present invention is not limited to this. For example, a resin film other than metal may be used.

An O-ring 16 is arranged around the outer periphery of the conductive foil 20 of the negative electrode plate 3, and the O-ring 16 and the conductive foil 20 are covered from the outside with, for example, a polyimide film 16a. Outside the polyimide film 16a, a circular member 17 in which a hole 17a having the same diameter as the second X-ray transmission hole 19 is formed at the center is arranged. Circular member 17
Is removably fastened and fixed to the negative electrode plate 3 by bolts 18 with the holes 17 a aligned with the second X-ray transmission holes 19. A plurality of bolts 18 are arranged at regular intervals in the circumferential direction at a position radially outside the O-ring 16,
As a result, the conductive foil 20 is arranged in the second X-ray transmission hole 19 in an airtight manner.

A screw hole 21 is formed in the positive electrode plate 4 at a position horizontally separated from the center of the housing 12 by a predetermined distance. The screw hole 21 is a hole for injecting the electrolytic solution 11 and is removably closed by the lid 22. The lid portion 22 includes a screw portion 23 to be screwed into the screw hole 21 and a flange 24 provided at an end of the screw portion 23. The screw portion 23 is screwed by turning the flange 24 by hand or the like. The screw hole 21 is closed by tightening the screw hole 21. In such a blockage, the flange 24
The O-ring 25 interposed between the O-ring 25 and the positive electrode plate 4 is pressed by the flange 24 to seal the screw hole 21.

In the receiving part 12, a bottomed escape hole (a relief part) 26 for the electrolytic solution 11 is provided at a portion facing the negative electrode plate 3 and the positive electrode plate 4 separated from the center of the receiving part 12 by a predetermined distance upward. Is formed. A bottomed escape hole 27 for the electrolyte solution 11 is also formed in a portion of the negative electrode plate 3 facing the inner end of the screw hole 21. As shown in FIG. 4, the bottomed escape holes 26 and 27 move downward from the inside of the first and second X-ray transmission holes 13 and 19 when the cell body 2 is placed with its vertical direction changed. Flowing electrolyte 1
1 is stored in the first and second X-ray transmitting holes 13 and 19.
This is for preventing the electrolytic solution 11 that lowers the strength of the wire from remaining. 1 and FIG.
8 is a positioning pin, 29 and 30 are negative electrode terminals,
This is a positive electrode terminal.

Next, the cell 1 for XAFS measurement having the above configuration
The measurement method using is described. First, the accommodation unit 12
And the first and second X-ray transmitting holes 13 and 19 below the center of the
Is placed so that is placed. At this time, as shown in FIG. 2, a predetermined amount of the electrolytic solution 11 is contained in the containing section 12, and the first and second X-ray transmitting holes 13 and 19 are contained.
Is filled with the electrolyte 11. Next, in this state, a current is applied to the negative electrode plate 3 and the positive electrode plate 4,
The positive electrode active material 14 arranged on the positive electrode plate 4 side is charged and discharged.

After the completion of charging and discharging, as shown in FIG.
Is placed in the vertical direction, and the electrolyte 11 in the first and second X-ray transmitting holes 13 and 19 is caused to flow downward to be collected in the bottomed escape holes 26 and 27, and the first and second X-ray transmitting holes 13 and 19 are stored. X-ray transmission hole 1
The electrolyte solution 11 is discharged from 3,19. Thereby, it is possible to avoid a decrease in X-ray intensity due to the electrolytic solution 11.
Next, in this state, the first and second X-ray transmission holes 13,
X-ray is transmitted through 19. First and second X-ray transmitting holes 1
X-rays transmitted through 3, 19 are the semiconductor detectors (not shown) (S
SD) and the like, and the X-ray absorption coefficient is calculated based on the measured values, thereby clarifying the local crystal structure of the positive electrode active material 14 and the details of the structural change due to charge and discharge. be able to.

When measuring the positive electrode active materials 14 having different charge / discharge amounts, the charge / discharge amount of the positive electrode active materials 14 is changed by, for example, changing the current supply time or the magnitude of the current during the charge / discharge described above. Measurement after charging / discharging, measurement while charging / discharging, or a constant current (for example, 1 m
A) is responded by integrating and supplying A) for a certain period of time (for example, 10 minutes) and performing measurement.

As described above, in this embodiment, since the positive electrode active material 14 of the battery material can be charged and discharged in the sealed cell 1, the charge and discharge amount of the positive electrode active material 14 can be changed. Same cell 1 and same positive electrode active material 14
XAFS measurement of the positive electrode active materials 14 having different charge / discharge amounts can be performed by using the method. As a result, the local crystal structure of each active material having different charge / discharge amounts and the details of the structural change due to the charge / discharge can be easily and accurately determined. Can be measured.

Further, the electrolyte solution 11 for reducing the intensity of X-rays can be discharged from the first and second X-ray transmission holes 13 and 19 simply by placing the cell 1 in a vertical direction. Therefore, X-ray transmission after charge / discharge can be quickly performed.

In the above-mentioned embodiment, the bottomed escape holes 26 and 27 are taken as an example of the escape portion. However, the present invention is not limited to this. Is adjusted so that when the direction of the cell 1 is changed, the first
Alternatively, the electrolyte in the second X-ray transmission holes 13 and 19 may be discharged.

FIG. 5 shows a circular member 17 in which a tapered notch 31 is provided on the outer peripheral edge of the hole 17a. When the notch 31 is provided in this manner, it can be used also as a reflection-type XRD measurement cell or a reflection-type XAFS measurement cell in which X-rays are incident obliquely, and the transmission as shown in FIG. It can also be used as a type XRD measurement cell.

[0031]

As is apparent from the above description, according to the present invention, the active material of the battery material can be charged and discharged in a sealed cell. Thereby, it is possible to perform XAFS measurement of active materials having different charge / discharge amounts using the same cell and the same active material,
As a result, it is possible to easily and accurately measure the local crystal structure of each active material having different charge / discharge amounts and the details of the structural change due to charge / discharge.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a battery material X according to an embodiment of the present invention.
It is a front view of the cell for line absorption fine structure measurement.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partial detailed view of FIG. 2;

FIG. 4 is an explanatory cross-sectional view for explaining a method for measuring an X-ray absorption fine structure of a battery material.

FIG. 5 is an explanatory cross-sectional view illustrating a cell for measuring an X-ray absorption fine structure of a battery material according to another embodiment of the present invention.

FIG. 6 is an explanatory cross-sectional view illustrating a cell for measuring an X-ray absorption fine structure of a battery material according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cell for X-ray absorption fine structure measurement 2 ... Cell main body 3 ... Negative electrode plate 4 ... Positive electrode plate 5 ... O-ring (insulating sealing member) 11 ... Electrolyte solution 12 ... Accommodating part 13 ... First X-ray transmission hole 14 ... Positive electrode active material 19 ... Second X-ray transmission hole 20 ... Conductive foil 26,27 ... Escape hole with bottom (escape part)

Claims (2)

[Claims] 1. A positive electrode plate and a negative electrode plate are hermetically joined to each other via an annular insulating seal member, and an electrolytic solution containing portion is provided in a space surrounded by each of the positive and negative plates and the insulating seal member. And forming a first X-ray transmission hole communicating with the housing portion in one of the positive electrode plate and the negative electrode plate, and forming an active material of a battery material in the first X-ray transmission hole. Is electrically sealed with the plate, and a second X-ray transmitting hole communicating with the housing portion is formed on the other plate, and a foil is formed on the second X-ray transmitting hole. An X-ray absorption fine structure measurement cell arranged in an airtight manner is prepared, and the electrolytic solution accommodated in the accommodating portion is filled with the first and second X-rays.
An electric current is applied to the positive and negative plates while penetrating the X-ray transmission holes to charge and discharge the active material. Then, the electrolyte is discharged from the first and second X-ray transmission holes while the electrolyte is discharged. A method for measuring an X-ray absorption fine structure of a battery material, wherein the structure of the active material is measured by transmitting X-rays through first and second X-ray transmission holes. 2. A positive electrode plate and a negative electrode plate are hermetically joined to each other via an annular insulating sealing member to form an electrolyte solution accommodating portion in a space surrounded by the positive and negative electrode plates and the sealing member. A first X-ray transmitting hole communicating with the housing portion is formed in one of the positive electrode plate and the negative electrode plate, and the first X-ray transmitting hole is provided with a battery material. The active material is placed in an airtight manner in a state of being electrically connected to the plate, and a second X-ray transmitting hole communicating with the housing portion is formed in the other plate, and the second X-ray transmitting hole is formed in the second plate. When the foil is arranged in an airtight manner and the orientation of the cell body is changed, the electrolytic solution that has penetrated the first and second X-ray transmitting holes is subjected to the first and second X-rays.
A cell for measuring an X-ray absorption fine structure of a battery material, comprising a relief portion for flowing to a side away from the X-ray transmission hole and discharging an electrolyte from the first and second X-ray transmission holes.