Cell for nuclear magnetic resonance measurement

Abstract

Provided is a cell for nuclear magnetic resonance measurement which demonstrate excellent stability over time. The cell for nuclear magnetic resonance measurement includes: a housing part having an opening for accommodating an active material layer and an electrolyte; a first electrode disposed on one surface side of the housing part and having a protrusion inserted into the opening; and a second electrode disposed on the other surface side of the housing part and having a protrusion inserted into the opening. The housing part is formed from ceramics.

Description

Cell for nuclear magnetic resonance measurement

[0001] The present invention relates to a nuclear magnetic resonance (NMS) measurement cell used for operand measurements, and more particularly to a nuclear magnetic resonance measurement cell used for operand measurements of charge and discharge.

[0002] Currently, rechargeable secondary batteries are widely used as power sources for mobile devices such as smartphones, personal computers, various electrical equipment, automobiles, and motorcycles. To evaluate the performance of secondary batteries, analyses of electrode reaction behavior or electrode state during battery operation are performed, and these analyses are desirable to be performed during battery operation, i.e., operands.

[0003] For example, Non-Patent Document 1 describes analyzing a battery using nuclear magnetic resonance (NMR). The experimental battery in Non-Patent Document 1 consists of a halved plastic cylinder made from polyetheretherketone (PEEK), and has cavities for the cathode, separator, and anode, as well as holes for connecting a current connector, which is later pressed together and encapsulated to ensure a constant, sealed pressure.

[0004] Oliver Pecher, et al. “Materials' Methods: NMR in Battery Research” Chem. Mater. 2017, 29, 213-242.

[0005] The experimental battery described in Non-Patent Document 1 above has an outer casing made of PEEK, making the internal cathode, separator, and anode susceptible to external environmental influences such as humidity, resulting in degradation due to the external environment. Therefore, with the experimental battery described in Non-Patent Document 1, for example, when evaluating the performance of the battery after a predetermined period of time, it is not possible to determine whether or not the performance is affected by the external environment, and thus the performance of the battery cannot be properly evaluated. The object of the present invention is to provide a nuclear magnetic resonance measurement cell with excellent aging stability.

[0006] The above objectives can be achieved by the following configurations. Invention [1] is a nuclear magnetic resonance measurement cell comprising a housing portion having an opening for housing an active material layer and an electrolyte, a first electrode disposed on one surface side of the housing portion and having a protrusion inserted into the opening, and a second electrode disposed on the other surface side of the housing portion and having a protrusion inserted into the opening, wherein the housing portion is made of ceramics. Invention [2] is the nuclear magnetic resonance measurement cell according to Invention [1], further comprising a pressing member disposed on at least one of the protrusions of the first electrode and the second electrode. Invention [3] is the nuclear magnetic resonance measurement cell according to Invention [1] or [2], further comprising a sealing portion disposed between the first electrode and the housing portion, and between the second electrode and the housing portion. Invention [4] is the nuclear magnetic resonance measurement cell according to any one of Inventions [1] to [3], wherein the ceramics are machinable ceramics or fine ceramics. Invention [5] is a nuclear magnetic resonance measurement cell according to any one of Inventions [1] to [4], wherein the first electrode and the second electrode are made of a non-magnetic metal. Invention [6] is a nuclear magnetic resonance measurement cell according to any one of Inventions [1] to [5], wherein the first electrode, the housing, and the second electrode are fixed in a stacked state.

[0007] According to the present invention, a nuclear magnetic resonance measurement cell with excellent temporal stability can be provided.

[0008] This is a schematic cross-sectional view showing an example of a nuclear magnetic resonance measurement cell according to an embodiment of the present invention. This is a schematic cross-sectional view showing an example of a nuclear magnetic resonance measurement cell according to an embodiment of the present invention, separated from the original. This is a schematic diagram showing an example of the housing portion of a nuclear magnetic resonance measurement cell according to an embodiment of the present invention. This is a schematic diagram showing an example of the first and second electrodes of a nuclear magnetic resonance measurement cell according to an embodiment of the present invention. This is a schematic perspective view showing an example of operando measurement using a solid-state NMR apparatus for a nuclear magnetic resonance measurement cell according to an embodiment of the present invention. This is a graph showing the charge and discharge results of Example 1. This is a graph showing the charge and discharge results of Comparative Example 1. ７ This graph shows the results of Li NMR measurements.

[0009] The nuclear magnetic resonance measurement cell of the present invention will be described in detail below based on the preferred embodiments shown in the attached drawings. The figures described below are illustrative for illustrating the present invention, and the present invention is not limited to the figures shown below. In the following, the "~" indicating a numerical range includes the numerical values ​​indicated on both sides. For example, ε is the numerical value ε α ~ Numerical value ε β Therefore, the range of ε is the numerical value ε α and the numerical value ε β This range includes ε α ≦ε≦ε β Furthermore, unless otherwise specified, all numerical values ​​include the generally acceptable error range in the relevant technical field.

[0010] [Cell for Nuclear Magnetic Resonance Measurement] A cell for nuclear magnetic resonance measurement will be described. Figure 1 is a schematic diagram showing an example of a cell for nuclear magnetic resonance measurement according to an embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing an example of a cell for nuclear magnetic resonance measurement according to an embodiment of the present invention, separated into parts. Figure 3 is a schematic diagram showing an example of the housing portion of a cell for nuclear magnetic resonance measurement according to an embodiment of the present invention. Figure 4 is a schematic diagram showing an example of the first electrode and second electrode of a cell for nuclear magnetic resonance measurement according to an embodiment of the present invention. The cell for nuclear magnetic resonance measurement 10 shown in Figures 1 and 2 has a housing portion 12 having an opening 12c for housing an active material layer and an electrolyte, a first electrode 14 arranged on one surface 12a side of the housing portion 12 and having a protrusion 15 inserted into the opening 12c, and a second electrode 16 arranged on the other surface 12b side of the housing portion 12 and having a protrusion 17 inserted into the opening 12c. The housing portion 12 is made of ceramics. Within the opening 12c of the housing portion 12, the protrusion 15 of the first electrode 14 and the protrusion 17 of the second electrode 16 are positioned opposite each other with a gap between them. A gap 19 is created between the protrusion 15 of the first electrode 14 and the protrusion 17 of the second electrode 16 within the opening 12c of the housing portion 12. The active material layer and the electrolyte are housed in the gap 19 within the opening 12c of the housing portion 12.

[0011] The nuclear magnetic resonance measurement cell 10 has a housing portion 12 made of ceramics and does not use resins such as PEEK. Because the opening 12c of the housing portion 12 is less affected by external environmental factors such as humidity, it exhibits excellent stability over time. "Excellent stability over time" means that even after a predetermined time has elapsed since the nuclear magnetic resonance measurement cell was manufactured, degradation of the battery components due to external environmental factors is less likely to occur, and the state of the battery components after the predetermined time can be accurately evaluated by NMR measurement. For example, even when repeated charging and discharging measurements are performed, degradation of the battery components due to external environmental factors is less likely to occur, and the state of the battery components can be accurately evaluated by NMR measurement.

[0012] As shown in Figure 3, the housing portion 12 has an external shape, for example, a rectangle with an internal angle of 90°. For example, the opening 12c is provided with its center aligned with the center of the external shape. Through holes 12d are provided at each corner of the external shape of the housing portion 12, resulting in four through holes 12d. The four through holes 12d are provided around the opening 12c. The first electrode 14 and the second electrode 16 apply voltage or current to the active material layer and the electrolyte. The first electrode 14 and the second electrode 16, including the terminal 18 described later, are made of a conductor, for example, a non-magnetic metal. Examples of non-magnetic metals that make up the first electrode 14 and the second electrode 16 and the terminal 18 described later include copper, brass, aluminum, and titanium. The first electrode 14 and the second electrode 16 and the terminal 18 described later are made of a metal selected from the group consisting of copper, brass, aluminum, and titanium.

[0013] As shown in Figure 4, the first electrode 14 has an outer shape, for example, a square with an inner angle of 90°. A protrusion 15 is provided on the surface 14a of the first electrode 14. The protrusion 15 is cylindrical, and for example, the center of the protrusion 15 is aligned with the center of the outer shape. A groove 21 is provided on the surface 14a of the first electrode 14 around the entire circumference of the protrusion 15. An O-ring 22 (see Figures 1 and 2) is provided in the groove 21 as a sealing part. Through holes 14d are provided at each corner of the outer shape of the first electrode 14, and there are four through holes 14d. The four through holes 14d are provided around the protrusion 15. A terminal 18 is also provided on the outer surface 14c of the first electrode 14. As shown in Figure 4, the second electrode 16 has an outer shape, for example, a square with an inner angle of 90°. A protrusion 17 is provided on the surface 16a of the second electrode 16. The protrusion 17 is cylindrical, and for example, the protrusion 17 is provided so that its center coincides with the center of the outer shape. A groove 21 is provided on the surface 16a of the second electrode 16 around the entire circumference of the protrusion 17. An O-ring 22 (see Figures 1 and 2) is provided in the groove 21 as a sealing part. Through holes 16d are provided at each corner of the outer shape of the second electrode 16, and there are four through holes 16d. The four through holes 16d are provided around the protrusion 17. In addition, a terminal 18 is provided on the outer surface 16c of the second electrode 16.

[0014] The protrusions 15 of the first electrode 14 and 17 of the second electrode 16 are both inserted into the opening 12c of the housing 12. The shape of the protrusion 15 as viewed from the surface 14a of the first electrode 14 and the shape of the protrusion 17 as viewed from the surface 16a of the second electrode 16 are the same as the shape of the opening 12c of the housing 12. Furthermore, the size of the protrusion 15 as viewed from the surface 14a of the first electrode 14 and the size of the protrusion 17 as viewed from the surface 16a of the second electrode 16 are such that they fit into the opening 12c of the housing 12. Also, for example, the housing 12, the first electrode 14 and the second electrode 16 have the same external shape and size. The terminal 18 is a connection part for applying voltage or current to the first electrode 14 and the second electrode 16 from the outside, and a conductor (not shown) is electrically connected to the terminal 18. A power supply is electrically connected to the conductor, and the power supply applies voltage or current to the first electrode 14 and the second electrode 16, and also applies voltage or current to the active material layer and the electrolyte.

[0015] As shown in Figure 1, the through-hole 12d of the housing portion 12, the through-hole 14d of the first electrode 14, and the through-hole 16d of the second electrode 16 are provided to communicate with each other, and a fixing screw 24 passes through them. The screw 24 is screwed into a nut 25. It is preferable that the screw 24 and nut 25 are non-magnetic. The nuclear magnetic resonance measurement cell 10 consists of three parts stacked together: the first electrode 14, the housing portion 12, and the second electrode 16, and is fixed together, for example, by a screw 24 and a nut 25. If the screw 24 is made of a conductive material such as metal, the screw 24 electrically insulates the first electrode 14 and the second electrode 16, for example. The method of electrically insulating is not particularly limited, but for example, a method of electrically insulating using a resin such as PEEK is exemplified. As described above, by providing an O-ring 22 as a sealing part in the groove 21, the airtightness between the housing portion 12 and the first electrode 14, and between the housing portion 12 and the second electrode 16 are improved. As a result, the overall airtightness of the nuclear magnetic resonance measurement cell 10 can be increased, leakage of electrolyte and other substances can be suppressed, and the influence of external environmental factors such as humidity can also be suppressed, thus improving the time-dependent stability of the nuclear magnetic resonance measurement cell 10. Furthermore, it is preferable that the O-ring 22 be made of a material insoluble in electrolyte and other substances. This further suppresses leakage of electrolyte and other substances. The seal portion is not particularly limited in its configuration as long as it can suppress leakage of electrolyte and other substances, and is not limited to the O-ring 22; for example, a chemical-resistant gasket can be used. An example of a gasket is a polytetrafluoroethylene (PTFE) gasket.

[0016] As described above, the active material layer and the electrolyte are housed in the gap 19 between the protrusion 15 of the first electrode 14 and the protrusion 17 of the second electrode 16 within the opening 12c of the housing portion 12. In the case of a battery, the active material layer is, for example, the positive electrode 30 and the negative electrode 34. In the case of a half-cell, the active material layer is the working electrode (positive or negative electrode) and the counter electrode. The electrolyte is held in the separator 32. In the case of a battery, the separator 32 is placed between the positive electrode 30 and the negative electrode 34. In the case of a half-cell, the separator 32 is placed between the working electrode (positive or negative electrode) and the counter electrode.

[0017] In the nuclear magnetic resonance measurement cell 10, for example, the pressing member 20 may be disposed on at least one of the convex portion 15 of the first electrode 14 and the convex portion 17 of the second electrode 16. FIGS. 1 and 2 show a configuration in which the pressing members 20 are respectively disposed on the surface 15a of the convex portion 15 of the first electrode 14 and the surface 17a of the convex portion 17 of the second electrode 16. The pressing member 20 on the surface 15a of the convex portion 15 of the first electrode 14 exerts a pressing force in direction D from the convex portion 15 of the first electrode 14 toward the housing portion 12 １ . The pressing member 20 on the surface 17a of the convex portion 17 of the second electrode 16 exerts a pressing force in direction D from the convex portion 17 of the second electrode 16 toward the housing portion 12 ２ . By providing the pressing member 20, pressure can be applied in a direction that narrows the gap 19 in the opening 12c of the housing portion 12 in the stacking direction Ds. That is, the pressing member 20 can apply pressure in the stacking direction Ds to the active material layer and the electrolyte provided in the gap 19, which enables, for example, stable charge-discharge measurement of the nuclear magnetic resonance measurement cell 10. The pressing member 20 is, for example, a disc spring, a leaf spring, or a wave washer. The disc spring, leaf spring, and wave washer are made of, for example, titanium, inconel, or phosphor bronze.

[0018] In the nuclear magnetic resonance measurement cell 10, a metal foil, a metal spacer, or the like may be disposed between the positive electrode 30 or the negative electrode 34 and the pressing member 20. A metal foil, a metal spacer, or the like may be disposed between the working electrode (positive electrode or negative electrode) or the counter electrode and the pressing member 20. The metal foil has, for example, a circular outer shape and is made of Ti. The metal spacer has, for example, a circular outer shape and is made of Cu or Ti.

[0019] The housing portion 12 is made of ceramics as described above. The ceramics are, for example, machinable ceramics or fine ceramics. More specifically, Macol® or Hotover® can be used as the ceramics, and zirconia, which is a fine ceramic, can also be used. The ceramics preferably have a porosity of 1% or less. Furthermore, the ceramics preferably exhibit diamagnetism. The porosity of the ceramics is calculated based on JIS R 1634 "Method for measuring the density and open porosity of sintered fine ceramics". If the housing portion 12 is made of machinable ceramics, it is easy to process it into the configuration of the housing portion 12 shown in Figure 3, for example. Furthermore, if the ceramics have a porosity of 1% or less, gases and liquids will not easily permeate the housing portion 12, the influence of external environmental factors such as humidity on the active material layer and electrolyte housed in the opening 12c can be reduced, and the temporal stability of the nuclear magnetic resonance measurement cell 10 is further improved.

[0020] For example, when performing operando measurements using a solid-state NMR apparatus, the nuclear magnetic resonance (NMS) cell 10 is placed inside the NMR coil 42 provided on the NMR probe head 40, as shown in Figure 5. The terminal 18 of the NMS cell 10 placed inside the NMR coil 42 is electrically connected to the charging terminal 44. Current is applied to the NMS cell 10 via the charging terminal 44 and through the terminal 18. In Figure 5, the same components as those shown in Figure 1 are denoted by the same reference numerals, and their detailed descriptions are omitted. In Figure 5, the screw 24 and nut 25 shown in Figure 1 are omitted from the illustration. When placing the NMS cell 10 inside the NMR coil 42 provided on the NMR probe head 40, the NMS cell 10 is covered with insulating tape that has electrical insulating properties to ensure electrical insulation. This eliminates the need to occupy extra space within the NMR coil 42 for insulation, allowing the nuclear magnetic resonance measurement cell 10 placed inside the NMR coil 42 to be made larger.

[0021] The active material layer and electrolyte are described below. (Active Material Layer) The active material layer is a layer containing active material and may be either a negative electrode active material layer or a positive electrode active material layer. Known materials can be used as the active material in the negative electrode active material layer, for example, silicon-based active materials such as Si, Si alloys, and silicon oxide; carbon-based active materials such as graphite and hard carbon; various oxide-based active materials such as lithium titanate; metallic lithium and lithium alloys. Known materials can be used as the active material in the positive electrode active material layer, for example, lithium transition metal oxides containing transition metal elements such as Co, Mn, and Ni. In addition, in the case of sodium-ion batteries, for example, non-graphitizable carbon (hard carbon), tin, antimony, phosphorus, alloys containing these, and titanium oxide can be used as the active material layer. In the case of potassium-ion batteries, for example, graphite, hard carbon, titanium oxide, potassium phosphate compounds, Prussian blue-based materials, polyanionic materials can be used as the active material layer. For example, in the case of a magnesium-ion battery, the active material layer may be magnesium-bismuth alloy, MgCo2O4, MgMn2O4, etc. For example, in the case of an aluminum-ion battery, the active material layer may be amorphous vanadium oxide, porous graphite, etc. For example, in the case of a calcium-ion battery, the active material layer may be Prussian blue, Prussian blue analogs, etc. For example, in the case of a zinc-ion battery, the active material layer may be zinc hydroxide, etc. The active material layer may also contain other materials besides the active material.

[0022] (Electrolyte) Any electrolyte may be used as long as it is used as an electrolyte for secondary batteries. Further, the electrolyte may be either a liquid electrolyte or a solid electrolyte. The solvent for the liquid electrolyte is not particularly limited, and examples thereof include organic solvents such as carbonate ester solvents (propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), ethyl methyl carbonate, dimethyl carbonate (DMC), etc.), ether solvents (glyme solvents such as tetraglyme (G4), triglyme, etc.); aliphatic quaternary amines such as pyridinium, piperidinium (N-methyl-N-propyl-piperidinium (PP13), etc.), pyrrolidinium (N,N-dimethylpyrrolidinium (Py11), N-methyl-N-ethylpyrrolidinium (Py12), N-methyl-N-butylpyrrolidinium (Py14), etc.), imidazolium (1-ethyl-3-methylimidazolium (EMI), dimethylimidazole (DMI), propylmethylimidazole (PMI), butylmethylimidazole (BMI), etc.), and ionic liquids composed of fluoride-based anions (bisfluorosulfonylamide (FSA) anion, bistrifluoromethylsulfonylamide (TFSA) anion, fluorotrifluoromethylsulfonylamide (FTA) anion, etc.) are used. One of these organic solvents and ionic liquids may be used alone, or two or more thereof may be used in combination.

[0023] Furthermore, while there are no particular limitations on the electrolyte salt used in the liquid electrolyte, in the case of lithium-ion batteries, highly dissociable lithium salts such as lithium hexafluoride phosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) are used. In the case of sodium-ion batteries, NaLiPF6, NaTFSA, NaFSA, and NaBF4 are used. In the case of potassium-ion batteries, KPF6, KFSA, KTFSA, and KBF4 are examples, and in the case of magnesium-ion batteries, Mg(TFSA)2, etc., and additives such as Mg(BH4)2 and MgCl2 are used. In the case of aluminum-ion batteries, aluminum halides (aluminum chloride (AlCl3), aluminum bromide (AlBr3), etc.) are used. In the case of calcium-ion batteries, Ca(TFSA)2 is used. In the case of zinc-ion batteries, zinc chloride (ZnCl2) and zinc sulfate (ZnSO4) are used.

[0024] As for solid electrolytes, in the case of lithium-ion batteries, La 0.51 Li 0.34 TiO 2.94 Li 1.3 Al 0.3 Ti 1.7 (PO4)3, Li7La3Zr2O 12 , 50Li4SiO4・50Li3BO3, Li 2.9 PO 3.3 N 0.46 (LIPON), Li 3.6 Si 0.6 P 0.4 O4, Li 1.07 Al 0.69 Ti 1.46 (PO4)3, Li 1.5 Al 0.5 Ge 1.5 Oxide-based solid electrolytes such as (PO4); Li 10 GeP2S 12 Li 3.25 Ge 0.25 P 0.75S4, 30Li2S・26B2S3・44LiI, 63Li2S・36SiS2・1Li3PO4, 57Li2S・38SiS2・5Li4SiO4, 70Li2S・30P2S5, 50Li2S・50GeS2, Li7P3S 11 Li 3.25 P 0.95 Sulfide-based solid electrolytes such as S4 are used. In the case of sodium-ion batteries, Na-β-Al2O ３ , NASICON, Na3PS4, Na3SbS4, Na7P3O 11 Na7P3S 11 These are used. In the case of potassium-ion batteries, K 2 / 3 Mg 2 / 3 Te 1 / 3 Examples include O2, and in the case of magnesium ion batteries, MgZr4(PO4)6, β-MgSO4:Mg(NO3)2-0.4MgO, Mg(BH4)(NH2), MgSc2Se4, etc. are used.

[0025] (Counter electrode) In the case of lithium-ion batteries, positive electrode materials such as metallic lithium, lithium nickelate, lithium cobaltate, and lithium manganeseate, and negative electrode materials pre-doped with lithium are used as the counter electrode. In the case of sodium-ion batteries, metallic sodium, sodium transition metal oxides (NaFeO2, NaCoO2, NaMnO2, etc.), sodium-doped titanium oxide, and hard carbon are used. In the case of potassium-ion batteries, metallic potassium and potassium-doped graphite are used. In the case of magnesium-ion batteries, metallic magnesium and magnesium-bismuth alloys are used. In the case of aluminum-ion batteries, metallic aluminum and porous graphite are used. In the case of calcium-ion batteries, metallic calcium is used. In the case of zinc-ion batteries, metallic zinc, porous carbon, and zinc alloys are used.

[0026] The present invention is basically configured as described above. Although the nuclear magnetic resonance measurement cell of the present invention has been described in detail above, the present invention is not limited to the embodiments described above, and various improvements or modifications may be made without departing from the spirit of the present invention.

[0027] The features of the present invention will be described in more detail below with reference to examples. The processing content, processing procedures, etc., shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below. The measuring battery (cell) of Example 1 and the measuring battery (cell) of Comparative Example 1 were each subjected to 5 charge-discharge cycles. The results are shown in Table 1 and Figures 6 and 7 below. Figure 6 is a graph showing the charge-discharge results of Example 1, and Figure 7 is a graph showing the charge-discharge results of Comparative Example 1. The measuring battery (cell) of Example 1 and the measuring battery (cell) of Comparative Example 1 will be described below.

[0028] (Example 1) Fabrication of a measurement battery (cell) Using the nuclear magnetic resonance measurement cell shown in Figures 1 and 2, a half-cell having a working electrode and a counter electrode was fabricated as a measurement battery (cell). A spherulite graphite electrode (HS-LIB-N-Gr001, manufactured by Hosen Co., Ltd.) coated on copper foil was used as the working electrode. Metallic lithium was used as the counter electrode. LiPF ６ An electrolyte solution was used, prepared by dissolving battery-grade ethylene carbonate (EC) / diethyl carbonate (DEC) (1:1 v / v%) (battery-grade, manufactured by Kishida Chemical Co., Ltd.) in a 1 M solvent. The protrusions of the first and second electrodes were cylindrical with a diameter of 7 mm. The opening of the housing was circular with an inner diameter of 8 mm. O-rings were provided in the grooves of the first and second electrodes. Chemical-resistant fluorine polymer O-rings (manufactured by Sakura Seal Co., Ltd.) that are insoluble in the electrolyte solution were used. The first and second electrodes were made of copper, and the housing was made of Macol®.

[0029] The protrusion (7 mm in diameter) of the first electrode was fitted into the opening (8 mm in diameter) of the housing, and the two components, the first electrode and the housing, were stacked together. The opening formed in the center of the housing was used as the electrode installation area. Inside the opening of the housing, the working electrode (7 mm in diameter), separator (glass filter: Whatman GF / D) (8 mm in diameter), and counter electrode were stacked in this order on the surface of the protrusion of the first electrode. Furthermore, a circular titanium foil, a circular copper spacer, and a titanium disc spring were stacked on top of the counter electrode. Next, 60 μL of the electrolyte solution was injected into the opening of the housing. Finally, the protrusion of the second electrode was fitted into the opening of the housing to install the second electrode. In this state, the through-hole of the first electrode, the through-hole of the housing, and the through-hole of the second electrode are in communication, and there are four communicating through-holes. Non-magnetic screws fitted with insulating bushings were passed through each of the four interconnected through-holes, and then the four non-magnetic screws were tightened with nuts to fix the first electrode, housing, and second electrode in a stacked state. This sealed the space between the first electrode and the housing, and between the second electrode and the housing, with O-rings. In this way, a measuring battery (nuclear magnetic resonance measurement cell) was fabricated. The non-magnetic screws were electrically insulated from the first electrode hole, housing, and second electrode by the insulating bushings.

[0030] Next, the fabricated measurement battery (nuclear magnetic resonance measurement cell) was subjected to constant current charge / discharge (CC) settings. The current density was set to 37.2 mA / g, and discharge (lithium insertion) and charge (lithium desorption) were performed within a sweep range of 0V to 2.5V. This charge / discharge process was repeated five times, and the charge / discharge capacity was recorded. The results are shown in Figure 6 and Table 1 below. The time required for five charge / discharge cycles was approximately five days. Regarding the measurement battery (nuclear magnetic resonance measurement cell) after five discharge cycles, ７ Li NMR measurements were performed to observe the state of Li inside the measurement battery (nuclear magnetic resonance measurement cell). The results are shown in Figure 8. Figure 8 is from Example 1. ７ This is a graph showing the results of Li NMR measurement. Example 1 is LiC around 44 ppm as shown in the NMR spectrum 50 in Figure 8. ６ (Li ＋A signal (in graphite) was observed. The NMR measurement was performed with a measurement battery (nuclear magnetic resonance cell) placed inside the NMR coil 42 provided in the NMR probe head 40, as shown in Figure 5, and with the charging terminal 44 electrically connected to the terminal. A solid-state NMR spectrometer (Bruker AVANCE III 500 NMR) was used for the NMR measurement.

[0031] (Comparative Example 1) Fabrication of a Measurement Battery (Cell) Comparative Example 1 differs from Example 1 in that the first electrode, housing, and second electrode are all made of PEEK. Furthermore, Comparative Example 1 has copper plates on the surface of the cylindrical protrusion of the first electrode and the surface of the cylindrical protrusion of the second electrode. Each copper plate is for applying current to the working electrode and counter electrode in the opening of the housing. A conductor for connecting to an external power source was connected to each copper plate. In Comparative Example 1, the measurement battery (nuclear magnetic resonance measurement cell) fabricated under the same conditions as Example 1 was charged and discharged with constant current charge / discharge (CC) settings. The results are shown in Figure 7 and Table 1 below. The period required for 5 charge / discharge cycles was approximately 5 days. For the measurement battery (nuclear magnetic resonance measurement cell) after 5 discharge cycles, ７ Li NMR measurements were performed to observe the state of Li inside the measurement battery (nuclear magnetic resonance measurement cell). As a result, Comparative Example 1 showed LiC at around 44 ppm. ６ (Li ＋ The signal (in graphite) could not be observed. This is thought to be because, in Comparative Example 1, the charging capacity became extremely small after 5 cycles, and Li no longer entered the graphite after 5 cycles. The NMR measurement of Comparative Example 1 was performed in the same manner as the NMR measurement of Example 1 described above.

[0032]

[0033] Although it took approximately 5 days to complete 5 charge-discharge cycles, as shown in Table 1 and Figure 6 above, Example 1 showed excellent stability over time, with the charge capacity (amount of lithium released) remaining almost constant at 322-324 mAh / g throughout the 5 cycles. On the other hand, as shown in Table 1 and Figure 7 above, when Comparative Example 1 underwent 5 charge-discharge cycles, the charge capacity (amount of lithium released) decreased with each cycle, resulting in large changes in charge capacity (amount of lithium released) throughout the 5 cycles and poor stability over time.

[0034] 10 Nuclear magnetic resonance measurement cell 12 Housing 12a One surface 12b Other surface 12c Opening 12d, 14d, 16d Through hole 14 First electrode 14a, 15a, 16a, 17a Surface 14c, 16c Outer surface 15, 17 Protrusion 16 Second electrode 18 Terminal 19 Gap 20 Pressing member 21 Groove 22 O-ring 24 Screw 25 Nut 30 Positive electrode 32 Separator 34 Negative electrode 40 NMR probe head 42 NMR coil 44 Terminal for charging 50 NMR spectrum D １ Direction D ２ Direction Ds stacking direction

Claims

1. A nuclear magnetic resonance (NMU) cell comprising: a housing portion having an opening for housing an active material layer and an electrolyte; a first electrode disposed on one surface of the housing portion and having a protrusion inserted into the opening; and a second electrode disposed on the other surface of the housing portion and having a protrusion inserted into the opening, wherein the housing portion is made of ceramics.

2. A nuclear magnetic resonance measurement cell according to claim 1, further comprising a pressing member disposed on at least one of the protrusions of the first electrode and the protrusions of the second electrode.

3. A magnetic resonance measuring cell according to claim 1, having a sealing portion disposed between the first electrode and the housing portion, and at least one of the spaces between the second electrode and the housing portion.

4. The magnetic resonance measurement cell according to claim 1, wherein the ceramics are machinable ceramics or fine ceramics.

5. The magnetic resonance measurement cell according to claim 1, wherein the first electrode and the second electrode are made of a non-magnetic metal.

6. A magnetic resonance measurement cell according to any one of claims 1 to 5, wherein the first electrode, the housing portion, and the second electrode are fixed in a stacked state.

Images