JP7279648B2 - electrode slurry - Google Patents

Description

The present disclosure relates to electrode slurries.

JP 2018-060815 A discloses an electrochemically active material having a zeta potential of less than 25 mV in absolute value when measured in a medium.

JP 2018-060815 A

Bulk-type all-solid-state batteries are being considered. Electrodes for bulk-type all-solid-state batteries are manufactured by a wet process. That is, the electrode is formed by applying the electrode slurry to the surface of the substrate and drying it. An electrode slurry is prepared by dispersing an electrode active material, a solid electrolyte, and the like in a dispersion medium.

Electrode active materials and solid electrolytes are particle groups. Solid electrolytes tend to react easily with water. Therefore, a low-polarity organic compound is used as a dispersion medium. Electrode active materials and solid electrolytes tend to agglomerate in low-polar non-aqueous dispersion media.

Addition of a dispersant may be considered to enhance the dispersion stability of the electrode slurry. However, the dispersant remains on the electrode and becomes a resistance component. That is, the addition of the dispersant may increase the battery resistance.

An object of the present disclosure is to improve the dispersion stability of the electrode slurry.

The technical configuration and effects of the present disclosure will be described below. However, the mechanism of action of the present disclosure includes speculation. Whether the mechanism of action is correct or not does not limit the scope of the claims.

The electrode slurry is used to manufacture electrodes for all-solid-state batteries.
The electrode slurry contains a first particle group, a second particle group, a binder, and a dispersion medium.
The dispersion medium is liquid. The dispersion medium contains a low-polarity organic compound.
A 1st particle group consists of an electrode active material.
The second particle group consists of a solid electrolyte.
Each of the first particle group and the second particle group is dispersed in the dispersion medium.
Condition (1) or Condition (2) below:
ζ _a ≦−25 mV and ζ _s ≦25 mV (1)
25mV≦ζ _a and −25mV≦ζ _s (2)
is filled.
"ζ _a " indicates the zeta potential of the first particle group in the dispersion medium.
“ζ _s ” indicates the zeta potential of the second particle group in the dispersion medium.

"Zeta potential" is an index of the charged state of a particle group (dispersoid). The zeta potential is measured in a dispersion system in which a group of particles to be measured (electrode active material or solid electrolyte) is dispersed in a dispersion medium. Zeta potential is measured by a zeta potential measuring device. For example, a zeta potential measuring device "Model DT-1202" manufactured by Dispersion Technology (or its equivalent) may be used. The measurement temperature is 25±2°C. The concentration of the object to be measured in the dispersion is 37±25% by weight.

For example, when the zeta potential is positive, the particles are considered relatively positively charged. For example, when the zeta potential is a negative value, the particles are considered to be relatively negatively charged. For example, when the zeta potential is zero, the particles are considered substantially uncharged.

In the electrode slurry, the main dispersoids are the electrode active material (first particle group) and the solid electrolyte (second particle group). The total of the electrode active material and the solid electrolyte accounts for, for example, 80 mass % or more of the non-volatile components contained in the electrode slurry. In the present disclosure, the charge state of the primary dispersoids is controlled. That is, the above condition (1) or condition (2) is satisfied.

When condition (1) or condition (2) above is satisfied, 'ζ _a ' and 'ζ _s ' are not zero. When the zeta potential is zero, particles are believed to settle according to Stokes' law. It is believed that the desired dispersion stability is not achieved when the zeta potential is zero.

When the above condition (1) or condition (2) is satisfied, it is considered that an electrostatic repulsive force is generated between particles in the first particle group (electrode active material). It is considered that electrostatic repulsion is generated between particles in the second particle group (solid electrolyte) as well. Furthermore, the electrostatic attraction generated between the first particle group (electrode active material) and the second particle group (solid electrolyte) can be sufficiently reduced. Alternatively, electrostatic repulsion may occur between the first particle group (electrode active material) and the second particle group (solid electrolyte). The synergistic effect of these actions is expected to increase the dispersion stability of the electrode slurry.

When the zeta potential is not zero and condition (1) or condition (2) above is not met, the particles can aggregate and settle due to the electrostatic attraction that occurs between the particles. As a result, it is considered that the desired dispersion stability cannot be obtained.

FIG. 1 is a schematic flow chart of the manufacturing method of this embodiment. FIG. 2 is a schematic cross-sectional view of the power storage element of this embodiment.

Hereinafter, embodiments of the present disclosure (hereinafter also referred to as “present embodiments”) will be described. However, the following description does not limit the scope of the claims.

In the present embodiment, descriptions such as "0.1 parts by mass to 10 parts by mass" indicate ranges including boundary values unless otherwise specified. That is, "0.1 parts by mass to 10 parts by mass" indicates a range of "0.1 parts by mass or more and 10 parts by mass or less".

<Electrode slurry>
The electrode slurry of the present embodiment is used to manufacture electrodes for all-solid-state batteries. For example, an electrode can be formed by applying an electrode slurry to the surface of an electrode current collector and drying it. The electrode in this embodiment may be a "positive electrode" or a "negative electrode". The electrode slurry contains a first particle group, a second particle group, a binder, and a dispersion medium.

The non-volatile component concentration (also referred to as “NV value”) of the electrode slurry may be, for example, 40% by mass to 80% by mass. A non-volatile component shows components other than a dispersion medium.

In the electrode slurry of this embodiment,
Condition (1) or Condition (2) below:
ζ _a ≦−25 mV and ζ _s ≦25 mV (1)
25mV≦ζ _a and −25mV≦ζ _s (2)
is filled. This is expected to improve the dispersion stability.

In the electrode slurry of this embodiment,
Condition (3) or Condition (4) below:
ζ _a ≦−25 mV and ζ _s ≦−25 mV (3)
25mV≦ζ _a and 25mV≦ζ _s (4)
may be satisfied. This is expected to improve the dispersion stability. When the above condition (3) or condition (4) is satisfied, both the first particle group and the second particle group are charged with the same sign. Therefore, it is considered that electrostatic repulsion occurs in all of "within the first particle group", "within the second particle group", and "between the first particle group and the second particle group", making it difficult for particles to aggregate. .

<<First particle group>>
A 1st particle group consists of an electrode active material. The "particle group" in this embodiment indicates an aggregate of particles (powder). The first particle group may have a median diameter of, for example, 1 μm to 30 μm. The first particle group may have a median diameter of, for example, 5 μm to 20 μm. "Median diameter" indicates the particle diameter at which the cumulative particle volume from the fine particle side is 50% of the total particle volume in the volume-based particle size distribution. The median diameter can be measured with a laser diffraction particle size distribution analyzer.

The first particle group may be made of, for example, a "positive electrode active material". The first particle group includes, for example, at least one selected from the group consisting of lithium cobalt oxide, lithium nickel oxide, lithium manganate, lithium nickel cobalt aluminate, lithium nickel cobalt manganate, and lithium iron phosphate. You can stay. The first particle group may contain, for example, at least one selected from the group consisting of nickel-cobalt lithium manganate and lithium iron phosphate.

Nickel cobalt lithium manganate is a composite oxide containing lithium (Li), nickel (Ni), cobalt (Co) and manganese (Mn). Lithium nickel-cobalt-manganese oxide may further contain other elements in addition to Li, Ni, Co, Mn and oxygen (O). The chemical composition of _lithium nickel-cobalt-manganese oxide may be represented, for _example , by the general formula "Li( _NiaCobMnc ) _O2 ". In the general formula, for example, the relationship "0<a<1, 0<b<1, 0<c<1, a+b+c=1" may be satisfied. In the general formula, for example, the relationship "0.2 < a < 0.5, 0.2 < b < 0.5, 0.2 < c < 0.5, a + b + c = 1" may be satisfied. .

Lithium iron phosphate is a complex phosphate containing Li and iron (Fe). Lithium iron phosphate may have a chemical composition such as " _LiFePO4 ", for example. Lithium iron phosphate may further contain other elements in addition to Li, Fe, phosphorus (P) and O.

The first particle group may be made of, for example, the "negative electrode active material". The first particle group includes, for example, graphite, soft carbon, hard carbon, silicon (Si), silicon oxide (SiO), silicon-based alloy, tin (Sn), tin oxide, tin-based alloy, indium-based alloy, and antimony-based alloy. , and at least one selected from the group consisting of lithium titanate. The first particle group may contain, for example, at least one selected from the group consisting of graphite and lithium titanate.

Lithium titanate is a composite oxide containing Li and titanium (Ti). Lithium titanate can have any chemical composition. Lithium titanate may have a chemical composition such as "Li ₄ Ti ₅ O ₁₂ ".

The first particle group exhibits a predetermined zeta potential (ζ _a ) in the dispersion medium. The zeta potential (ζ _a ) of the first particle group can be adjusted by, for example, drying conditions of the first particle group. The zeta potential (ζ _a ) of the first particle group may be −25 mV or less, for example. The zeta potential (ζ _a ) of the first particle group may be −36 mV or less, for example. The zeta potential (ζ _a ) of the first particle group may be, for example, −36 mV to −25 mV.

The zeta potential (ζ _a ) of the first particle group may be, for example, 25 mV or more. The zeta potential (ζ _a ) of the first particle group may be, for example, 33 mV or more. The zeta potential (ζ _a ) of the first particle group may be, for example, 34 mV or more. The zeta potential (ζ _a ) of the first particle group may be, for example, 35 mV or more. The zeta potential (ζ _a ) of the first particle group may be, for example, 25 mV to 35 mV.

<<Second particle group>>
The second particle group consists of a solid electrolyte. The second particle group may have a median diameter of, for example, 0.05 μm to 5 μm. The second particle group may have a median diameter of, for example, 0.1 μm to 1 μm.

The second particle group may be made of, for example, a "sulfide solid electrolyte". The sulfide solid electrolyte may be glass, for example. The sulfide solid electrolyte may be, for example, glass ceramics (also called “crystallized glass”).

A sulfide solid electrolyte contains sulfur (S) and Li. The sulfide solid electrolyte may further contain P, for example. That is, the sulfide solid electrolyte may contain lithium phosphorus sulfide or the like. The sulfide solid electrolyte may further contain, for example, a halogen element. The sulfide solid electrolyte may further contain, for example, iodine (I), bromine (Br), and the like. The sulfide solid electrolyte may further contain, for example, O, Si, germanium (Ge), Sn and the like.

Sulfide solid electrolytes include, for example, Li ₂ SP ₂ S ₅ , Li ₂ S—SiS ₂ , LiI—Li ₂ S—SiS ₂ , LiI—Si ₂ SP ₂ S ₅ , LiI—LiBr—Li ₂ SP ₂ S ₅ , LiI-Li ₂ SP 2 S ₅ , LiI- _{Li 2 O} -Li ₂ SP ₂ S ₅ , LiI-Li ₂ SP ₂ O ₅ , LiI-Li ₃ PO ₄ —P ₂ S ₅ and Li ₂ SP ₂ S ₅ —GeS ₂ .

Here, for example, "Li ₂ SP ₂ S ₅ " indicates that the sulfide solid electrolyte consists of a component derived from "Li ₂ S" and a component derived from "P ₂ S ₅ ". Li ₂ SP ₂ S ₅ can be produced, for example, by a mechanochemical reaction between Li ₂ S and P ₂ S ₅ . A mixing ratio of Li ₂ S and P ₂ S ₅ is arbitrary. Li ₂ S and P ₂ S ₅ satisfy, for example, a molar ratio of “Li ₂ S/P ₂ S ₅ =50/50” to “Li ₂ S/P ₂ S ₅ =90/10”. may Li ₂ S and P ₂ S ₅ satisfy, for example, a molar ratio of “Li ₂ S/P ₂ S ₅ =60/40” to “Li ₂ S/P ₂ S ₅ =80/20”. may

Furthermore, for example, "10LiI-10LiBr-80 [0.75Li ₂ S-0.25P ₂ S ₅ ]" contains 10 mol% of the component derived from "LiI" and 10 mol% of the component derived from "LiBr". , "0.75Li ₂ S-0.25P ₂ S ₅ " is 80 mol %. “0.75Li ₂ S-0.25P ₂ S ₅ ” contains 75 mol % of the component derived from Li ₂ S in “0.75Li ₂ S-0.25P ₂ S ₅ ”, and the component derived from P ₂ S ₅ is 25 mol%.

The second particle group may be made of, for example, an "oxide solid electrolyte". The second particle group includes, for example, at least one selected from the group consisting of LiNbO ₃ , Li ₃ PO ₄ , LiPON, Li ₃ BO ₃ —Li ₂ SO ₄ , LISICON, and Li ₇ La ₃ Zr ₂ O ₁₂ . may contain.

The blending amount of the second particle group may be, for example, 10 parts by mass to 60 parts by mass with respect to 100 parts by mass of the first particle group (electrode active material). The blending amount of the second particle group may be, for example, 20 to 40 parts by mass with respect to 100 parts by mass of the first particle group.

The second particle group exhibits a predetermined zeta potential (ζ _s ) in the dispersion medium. The zeta potential (ζ _s ) of the second particle group can be adjusted by, for example, drying conditions of the second particle group. The zeta potential (ζ _s ) of the second particle group may be, for example, 25 mV or less. The zeta potential (ζ _s ) of the second particle group may be −25 mV or less, for example. The zeta potential (ζ _s ) of the second particle group may be −37 mV or less, for example. The zeta potential (ζ _s ) of the second particle group may be −39 mV or less, for example. The zeta potential (ζ _s ) of the second particle group may be −40 mV or less, for example. The zeta potential (ζ _s ) of the second particle group may be, for example, −40 mV to 25 mV. The zeta potential (ζ _s ) of the second particle group may be, for example, −40 mV to −25 mV.

The zeta potential (ζ _s ) of the second particle group may be -25 mV or more, for example. The zeta potential (ζ _s ) of the second particle group may be, for example, 25 mV or more. The zeta potential (ζ _s ) of the second particle group may be, for example, 39 mV or more. The zeta potential (ζ _s ) of the second particle group may be, for example, 41 mV or more. The zeta potential (ζ _s ) of the second particle group may be, for example, 42 mV or more. The zeta potential (ζ _s ) of the second particle group may be, for example, −25 mV to 42 mV. The zeta potential (ζ _s ) of the second particle group may be, for example, 25 mV to 42 mV.

《Binder》
A binder may bind the solid components together at the electrode. The binder may be dissolved in the dispersion medium. The binder may be dispersed in the dispersion medium. The binder can contain optional ingredients. Binders include, for example, polyvinylidene fluoride (PVdF), vinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), butyl rubber (IIR), and acrylic It may contain at least one selected from the group consisting of resins. For example, PVdF tends to have good voltage resistance. For example, PVdF tends to be less reactive with sulfide solid electrolytes.

The blending amount of the binder may be, for example, 0.1 to 10 parts by mass with respect to 100 parts by mass of the first particle group (electrode active material). The binder may dissolve in the dispersion medium. In this case, it is considered that the zeta potential cannot be measured. Therefore, it is considered that binders are not compatible with the concept of zeta potential. Also, the amount of the binder compounded is generally small. Even if the binder were electrified, it would have little effect on the dispersion stability of the electrode slurry.

《Dispersion medium》
The dispersion medium is liquid. The dispersion medium contains a low-polarity organic compound. The dispersion medium may consist essentially of a low-polarity organic compound. The low-polarity organic compound may contain, for example, a carboxylic acid ester. Low polar organic compounds consist of, for example, ethyl acetate, butyl acetate, butyl butyrate, pentyl butyrate, hexyl butyrate, butyl pentanoate, pentyl pentanoate, hexyl pentanoate, butyl hexanoate, pentyl hexanoate, and hexyl hexanoate. At least one selected from the group may be included. For example, butyl butyrate tends to be less reactive with sulfide solid electrolytes.

《Other Ingredients》
The electrode slurry may further contain other components as long as it contains the above components. The electrode slurry may further contain, for example, a conductive material or the like. The conductive material can form electronically conductive paths in the electrodes. The conductive material can contain any component. The conductive material may contain, for example, at least one selected from the group consisting of acetylene black, Ketjenblack (registered trademark), vapor grown carbon fiber (VGCF), carbon nanotube (CNT), and graphene flakes. good. The blending amount of the conductive material may be, for example, 0.1 to 10 parts by mass with respect to 100 parts by mass of the first particle group (electrode active material).

A conductive material can have any zeta potential. Conductive materials tend to be positively charged. For example, even if the conductive material is subjected to a drying process or the like, the zeta potential of the conductive material tends not to change significantly. Furthermore, the amount of the conductive material to be blended tends to be small and the specific gravity tends to be small. Therefore, it is considered that the zeta potential of the conductive material has little effect on the dispersion stability of the electrode slurry.

The electrode slurry may contain a dispersant. However, the addition of a dispersant may increase battery resistance. The electrode slurry may be substantially free of dispersants. A reduction in battery resistance is expected because the electrode slurry does not substantially contain a dispersant.

<Manufacturing method>
FIG. 1 is a schematic flow chart of the manufacturing method of this embodiment.
In this embodiment, a "method for producing an electrode slurry," a "method for producing an electrode," and a "method for producing an all-solid-state battery" are provided.
The manufacturing method in the present disclosure includes the following (A) to (D).
(A) Pretreatment is applied to at least one of the first particle group and the second particle group.
(B) An electrode slurry is prepared by dispersing the first particle group, the second particle group and a binder in a dispersion medium.
(C) The electrode is produced by applying the electrode slurry to the surface of the substrate and drying it.
(D) Fabricating an all-solid-state battery, including the electrodes.

The pretreatment is performed so that the above condition (1) or condition (2) is satisfied. Pretreatment may include, for example, drying at least one of the first particle group and the second particle group in a low dew point environment. A low dew point environment may, for example, have a dew point of -65°C to -30°C. The drying temperature may be, for example, 40°C to 70°C.

The first particle group and the like are dispersed in the dispersion medium by an arbitrary dispersion device. For example, an ultrasonic homogenizer or the like may be used.

The electrode slurry is applied to the surface of the substrate by any applicator and dried to form the electrode. The substrate may be, for example, an electrode current collector. When the electrode is a positive electrode, the electrode current collector may contain, for example, aluminum (Al) foil or the like. When the electrode is a negative electrode, the electrode current collector may contain, for example, Ni foil, copper (Cu) foil, or the like.

The substrate may be, for example, a temporary support. An electrode may be formed by applying an electrode slurry to the surface of the temporary support and drying it. After forming the electrodes, the electrodes may be transferred from the temporary support to another member.

FIG. 2 is a schematic cross-sectional view of the power storage element of this embodiment.
A power storage element 50 is formed by stacking the positive electrode 10 , the separator layer 30 and the negative electrode 20 . A bulk-type all-solid-state battery is manufactured by enclosing the power storage element 50 in a housing (not shown). The housing may be, for example, a pouch made of aluminum laminate film.

The all-solid-state battery may include one power storage element 50 alone. The all-solid battery may include a plurality of power storage elements 50 . A plurality of power storage elements 50 may be stacked in the z-axis direction of FIG. 2, for example. A plurality of power storage elements 50 may be electrically connected in series. A plurality of power storage elements 50 may be electrically connected in parallel.

Separator layer 30 is disposed between positive electrode 10 and negative electrode 20 . Separator layer 30 physically separates positive electrode 10 and negative electrode 20 . The separator layer 30 conducts Li ions. Separator layer 30 is substantially non-conductive to electrons. Separator layer 30 may contain, for example, a solid electrolyte and a binder.

The all-solid-state battery of this embodiment is expected to exhibit low battery resistance. The electrodes of this embodiment are formed of an electrode slurry with high dispersion stability. Therefore, it is considered that ion conduction is smooth in the electrode of the present embodiment. It is believed that smooth ion conduction in the electrodes reduces the battery resistance.

Hereinafter, examples of the present disclosure (hereinafter also referred to as “present examples”) will be described. However, the following description does not limit the scope of the claims.

<Preparation of electrode slurry>
《No. 1>>
The following materials were prepared.
First particle group: Li(Ni _1/3 Co _1/3 Mn _1/3 )O ₂
Second particle group: 10LiI-10LiBr-80 [0.75Li ₂ S-0.25P ₂ S ₅ ]
Conductive material: VGCF
Binder: PVdF
Dispersion medium: butyl butyrate

The first particle group (positive electrode active material) was left for 10 hours under a normally air-conditioned environment (dew point 3°C, temperature 25°C). After standing, the first particle group was dispersed in butyl butyrate. After dispersion, the zeta potential was measured. The zeta potential (ζ _a ) of the first particle group was −19 mV. In this example, a zeta potential measuring device "DT-1202" manufactured by Dispersion Technology was used.

The second particle group (sulfide solid electrolyte) was left for 10 hours in a glove box (dew point -30°C, temperature 25°C). After standing, the second particle group was dispersed in butyl butyrate. After dispersion, the zeta potential was measured. The zeta potential (ζ _s ) of the second particle group was 41 mV.

A conductive material was dispersed in butyl butyrate. The zeta potential of the conductive material was measured. The zeta potential (ζ _c ) of the conductive material was 45 mV.

A non-volatile component was dispersed in the dispersion medium by an ultrasonic homogenizer. The composition of the non-volatile component was "first particle group (positive electrode active material)/second particle group (sulfide solid electrolyte)/conductive material/binder=60/30/5/5 (mass ratio)". From the above, No. 1 electrode slurry was prepared.

《No. 2 to No. 12>>
As shown in Table 1 below, an electrode slurry was prepared in the same manner as in Comparative Example 1, except that the drying conditions for the first particle group and the second particle group were changed.

《No. 13 to No. 24>>
Comparative Example 1, etc., except that LiFePO ₄ is used as the first particle group instead of Li(Ni _1/3 Co _1/3 Mn _1/3 )O ₂ as shown in Table 2 below. Similarly, an electrode slurry was prepared.

《No. 25 to No. 36>>
As shown in Table 3 below, a negative electrode active material (Li ₄ Ti ₅ O ₁₂ ) was used as the first particle group instead of the positive electrode active material. The composition of the non-volatile component was "first particle group (negative electrode active material)/second particle group (sulfide solid electrolyte)/conductive material/binder=63/26/5/6 (mass ratio)". An electrode slurry was prepared in the same manner as in Comparative Example 1 and the like, except for these.

《No. 37 to No. 48>>
As shown in Table 4 below, a negative electrode active material (graphite) was used as the first particle group instead of the positive electrode active material. The composition of the non-volatile component was "first particle group (negative electrode active material)/second particle group (sulfide solid electrolyte)/binder=81/16/3 (mass ratio)". An electrode slurry was prepared in the same manner as in Comparative Example 1 and the like, except for these.

<Evaluation>
《Dispersion stability》
After preparation of the electrode slurry, the electrode slurry was allowed to stand for 2 hours. After standing still for 2 hours, the particle size of the electrode slurry was measured with a grind gauge. In this example, the size of the third largest particle was defined as the particle size of the electrode slurry. The particle size of the electrode slurry is shown in Tables 1 to 4 below. It is considered that the smaller the particle size of the electrode slurry, the higher the dispersion stability of the electrode slurry.

《Battery performance》
(Formation of positive electrode)
With the applicator, No. 1 to No. 24 electrode slurries were applied to the surface of the Al foil. The thickness of the coating film was 118 μm (target value). A positive electrode was formed by drying the coating film. For example, if the particle size of the electrode slurry is 80% or less of the thickness of the coating film (that is, 94 μm or less), coating defects (such as “streaks”) are unlikely to occur.

(Formation of separator layer)
A non-volatile component was dispersed in the dispersion medium by an ultrasonic homogenizer. A separator slurry was thus prepared. The composition of non-volatile components was "sulfide solid electrolyte/binder=96/4 (mass ratio)". A separator layer was formed by applying the separator slurry to the surface of the temporary support (Al foil) and drying it.

(Formation of negative electrode)
With the applicator, No. 25 to No. 48 electrode slurries were applied to the surface of the Ni foil. The thickness of the coating film was 110 μm (target value). A negative electrode was formed by drying the coating film. For example, if the particle size of the electrode slurry is 80% or less of the thickness of the coating film (that is, 88 μm or less), coating defects are less likely to occur.

(assembly)
A power storage element was formed by stacking the positive electrode, the separator layer and the negative electrode. A pouch made of an aluminum laminate film was prepared as a housing. A storage element was enclosed in the housing. As described above, an all-solid-state battery was manufactured.

In this embodiment, No. 1 to No. A positive electrode formed by the electrode slurry of No. 24; No. 30 is combined with the negative electrode formed by the electrode slurry of No. 30. 1 to No. 24 all-solid-state batteries were fabricated respectively.

In this embodiment, No. a positive electrode formed by the electrode slurry of No. 6; 25 to No. No. 48 is combined with the negative electrode formed by the electrode slurry of No. 48. 25 to No. 48 all-solid-state batteries were fabricated respectively.

(Measurement of DC resistance)
Initial charge/discharge was performed on the all-solid-state battery. After the initial charge and discharge, the SOC (State Of Charge) of the all-solid-state battery was adjusted to 50%. After adjusting the SOC, the all-solid-state battery was discharged for 10 seconds with a discharge current of 3C under a temperature environment of 25°C. A voltage drop was measured 10 seconds after the start of discharge. The battery resistance was calculated by dividing the voltage drop by the discharge current. The results are shown in Tables 1 to 4 below. Note that "3C" indicates the current at which the full charge capacity is discharged in 20 minutes.

<Results>
As shown in Tables 1 to 4 above, when the electrode slurry satisfies the condition (1) or the condition (2), the dispersion stability of the electrode slurry tends to improve. Furthermore, when condition (1) or condition (2) is satisfied, there is also a tendency for the battery resistance to decrease.

This embodiment and this example are illustrative in all respects. This embodiment and this example are not restrictive. The technical scope defined by the description of the scope of claims includes all modifications in the meaning equivalent to the description of the scope of claims. The technical scope determined by the description of the claims also includes all modifications within the scope of equivalents of the description of the claims.

10 positive electrode, 20 negative electrode, 30 separator layer, 50 storage element.

Claims (3)

An electrode slurry used to manufacture an electrode for an all-solid-state battery, comprising:
including a first particle group, a second particle group, a binder, and a dispersion medium;
the dispersion medium is a liquid,
The dispersion medium contains a carboxylic acid ester ,
The first particle group is made of an electrode active material,
The second particle group is made of a solid electrolyte,
Each of the first particle group and the second particle group is dispersed in the dispersion medium,
Condition (1) or Condition (2) below:
ζ _a ≦−25 mV and ζ _s <0 mV (1)
25 mV≦ζ _a and 0 mV < ζ _s (2)
is filled and
ζ _a represents the zeta potential of the first particle group in the dispersion medium,
ζ _s represents the zeta potential of the second particle group in the dispersion medium;
electrode slurry. The carboxylic acid ester is selected from the group consisting of ethyl acetate, butyl acetate, butyl butyrate, pentyl butyrate, hexyl butyrate, butyl pentanoate, pentyl pentanoate, hexyl pentanoate, butyl hexanoate, pentyl hexanoate, and hexyl hexanoate. including at least one selected
The electrode slurry according to claim 1. Condition (3) or Condition (4) below:
ζ _a ≦−25 mV, and ζ _s ≦-25mV (3)
25mV≦ζ _a , and 25 mV≦ζ _s (4)
is filled with
The electrode slurry according to claim 1 or 2.

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