JP2018186016A - Lithium battery and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure physical and electrical connection between an electrode and a current collecting member while avoiding deterioration of the electrical performance and heat resistance performance of a lithium battery.SOLUTION: A lithium battery includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a solid electrolyte layer disposed between the positive electrode and the negative electrode and including a solid electrolyte having lithium ion conductivity, a positive electrode side current collecting member disposed on the side opposite to the solid electrolyte layer with respect to the positive electrode, and a negative electrode side current collecting member disposed on the side opposite to the solid electrolyte layer with respect to the negative electrode. At least one of the positive electrode and the negative electrode includes a specific material that is at least one of a lithium halide hydrate and a lithium halide hydroxide.SELECTED DRAWING: Figure 1

Description

  The technology disclosed by this specification is related with a lithium battery.

  In recent years, with the spread of electronic devices such as personal computers and mobile phones, the spread of electric vehicles, and the expansion of the use of natural energy such as sunlight and wind power, the demand for high-performance batteries is increasing. In particular, utilization of an all-solid lithium ion secondary battery (hereinafter referred to as an “all-solid battery”) in which the battery elements are all solid is expected. Compared to conventional lithium ion secondary batteries that use an organic electrolyte in which a lithium salt is dissolved in an organic solvent, all solid batteries are safe because there is no risk of leakage or ignition of the organic electrolyte, Since the exterior can be simplified, the energy density per unit mass or unit volume can be improved.

  The all solid state battery includes a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, and a solid electrolyte layer disposed between the positive electrode and the negative electrode and including a solid electrolyte having lithium ion conductivity. Hereinafter, the positive electrode and the negative electrode are collectively referred to as electrodes. The all solid state battery includes a positive electrode side current collecting member disposed on the opposite side to the solid electrolyte layer with respect to the positive electrode, and a negative electrode side current collecting member disposed on the opposite side to the solid electrolyte layer with respect to the negative electrode. Is provided. Hereinafter, the positive electrode side current collecting member and the negative electrode side current collecting member are collectively referred to as a current collecting member.

  The physical and electrical connection between the electrode and the current collecting member on the positive electrode side and the negative electrode side of the all solid state battery is ensured by, for example, a polymer binder contained in the electrode (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2015-82362

  In general, a polymer binder does not have ionic conductivity and has poor heat resistance. Therefore, in the configuration in which the physical and electrical connection between the electrode and the current collecting member is ensured by the polymer binder, there is a problem that the electrical performance and heat resistance performance of the all solid state battery are deteriorated.

  Such problems are not limited to all-solid-state lithium ion secondary batteries, but are common to other lithium batteries (for example, lithium-air batteries and lithium flow batteries) that use a solid electrolyte material having lithium ion conductivity. It is a problem.

  In this specification, the technique which can solve the subject mentioned above is disclosed.

  The technology disclosed in the present specification can be realized as, for example, the following forms.

(1) A lithium battery disclosed in this specification includes a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, and a solid electrolyte having lithium ion conductivity disposed between the positive electrode and the negative electrode. A solid electrolyte layer including: a positive electrode side current collector disposed on the opposite side of the solid electrolyte layer with respect to the positive electrode; and a negative electrode side disposed on the opposite side of the solid electrolyte layer with respect to the negative electrode In the lithium battery including the current collecting member, at least one of the positive electrode and the negative electrode includes a specific material that is at least one of a hydrate of lithium halide and a hydroxide of lithium halide. Lithium halide hydrate and lithium halide hydroxide have an adhesion function between substances. In the present lithium battery, since at least one of the positive electrode and the negative electrode includes a specific material that is at least one of lithium hydrate and lithium halide hydroxide, A physical and electrical connection between at least one and the current collecting member is ensured. Therefore, according to the present lithium battery, while avoiding a decrease in the electrical performance and heat resistance performance of the lithium battery due to the use of the polymer binder, the physical and the current between the current collector and at least one of the positive electrode and the negative electrode Electrical connection can be ensured and the performance of the lithium battery can be improved.

(2) In the lithium battery, the content ratio of the specific material in the negative electrode may be 16 vol% or more and 63 vol% or less. According to this lithium battery, good electrical connection between the negative electrode and the current collecting member can be ensured, and the performance of the lithium battery can be effectively improved.

(3) In the lithium battery, the content ratio of the specific material in the negative electrode may be 40 vol% or more and 60 vol% or less. According to the present lithium battery, a better electrical connection between the negative electrode and the current collecting member can be ensured, and the performance of the lithium battery can be improved extremely effectively.

(4) In the lithium battery, the halogen element of the lithium halide may include at least iodine. A hydrate of lithium halide containing at least iodine as a halogen element and a hydroxide of lithium halide have an excellent adhesion function between substances. Therefore, according to the present lithium battery, the physical and electrical connection between at least one of the positive electrode and the negative electrode and the current collecting member can be extremely strengthened, and the performance of the lithium battery can be effectively improved. Can do.

(5) A method of manufacturing a lithium battery disclosed in the present specification is arranged between a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, the positive electrode and the negative electrode, and has lithium ion conductivity. A solid electrolyte layer including a solid electrolyte, a positive electrode side current collecting member disposed on the opposite side of the solid electrolyte layer with respect to the positive electrode, and a solid electrolyte layer disposed on the opposite side of the negative electrode with respect to the negative electrode. And a negative electrode side current collecting member, wherein the first electrode precursor for forming one of the positive electrode and the negative electrode is a first electrode precursor containing lithium halide. A first step of preparing an electrode precursor and a second electrode precursor for forming the other of the positive electrode and the negative electrode, the first electrode precursor, and the second electrode precursor Body, the solid electrolyte layer, and the positive electrode side collector A second step of laminating a member and the negative electrode side current collecting member, and the first electrode precursor is made to absorb moisture, thereby halogenating the lithium halide contained in the first electrode precursor And a third step of changing to a specific material that is at least one of lithium hydrate and lithium halide hydroxide. According to the method for producing a lithium battery, the first electrode precursor is made to absorb moisture, whereby lithium halide contained in the first electrode precursor is converted into lithium hydroxide hydrate and lithium halide hydroxide. It can be changed to a specific material that is at least one of the objects. As a result, the electrode formed from the first electrode precursor includes a specific material that is at least one of lithium hydrate and lithium halide hydroxide having an adhesion function between substances. Can do. Therefore, according to the manufacturing method of this lithium battery, the physical and electrical connection between this electrode and a current collection member can be ensured, and the performance of the manufactured lithium battery can be improved.

(6) In the method for manufacturing a lithium battery, moisture absorption of the first electrode precursor in the third step may be performed in a state where the first electrode precursor is heated. According to the method for producing a lithium battery, the lithium halide contained in the first electrode precursor can be promoted to be changed into a specific material, and is specified in the electrode formed from the first electrode precursor. Material can be produced effectively. Therefore, according to the manufacturing method of the present lithium battery, the physical and electrical connection between the electrode and the current collecting member can be further strengthened.

(7) In the method for manufacturing a lithium battery, the second electrode precursor contains lithium halide, and the third step includes absorbing the second electrode precursor to absorb moisture. The lithium halide contained in the electrode precursor may be changed to a specific material that is at least one of a hydrate of lithium halide and a hydroxide of lithium halide. According to the method for producing a lithium battery, the second electrode precursor is made to absorb moisture, whereby lithium halide contained in the second electrode precursor is converted into lithium hydroxide hydrate and lithium halide hydroxide. It can be changed to a specific material that is at least one of the objects. Therefore, according to the manufacturing method of the present lithium battery, in addition to the electrode formed from the first electrode precursor, the electrode formed from the second electrode precursor also has a halogenation having a function of bonding between substances. A specific material that is at least one of lithium hydrate and lithium halide hydroxide can be included, thereby ensuring physical and electrical connection between both electrodes and the current collector be able to.

(8) In the method for manufacturing a lithium battery, moisture absorption of the second electrode precursor in the third step may be performed in a state where the second electrode precursor is heated. According to the method for manufacturing the lithium battery, the lithium halide contained in the second electrode precursor can be promoted to be changed into a specific material, and the lithium electrode is specified in the electrode formed from the second electrode precursor. Material can be produced effectively. Therefore, according to the manufacturing method of the present lithium battery, the physical and electrical connection between the electrode and the current collecting member can be further strengthened.

(9) In the method for manufacturing a lithium battery, the temperature in the heated state in the third step may be 25 ° C. or higher and 200 ° C. or lower. According to the method for producing a lithium battery, it is possible to promote the change of the lithium halide contained in the electrode precursor into a specific material by a relatively low temperature treatment. The physical and electrical connection between the electrode and the current collecting member can be ensured while suppressing the influence of heat.

(10) In the method for manufacturing a lithium battery, the halogen element of the lithium halide may include at least iodine. A hydrate of lithium halide containing at least iodine as a halogen element and a hydroxide of lithium halide have an excellent adhesion function between substances. Therefore, according to the method for manufacturing the lithium battery, physical and electrical connection between the electrode and the current collecting member can be extremely strengthened, and the performance of the manufactured lithium battery can be effectively improved. Can do.

  The technology disclosed in the present specification can be realized in various forms, for example, in the form of a lithium battery, an all solid lithium battery, an all solid lithium ion secondary battery, a manufacturing method thereof, or the like. It is possible to realize.

It is explanatory drawing which shows roughly the cross-sectional structure of the all-solid-state lithium ion secondary battery 102 in this embodiment. It is a flowchart which shows an example of the manufacturing method of the all-solid-state battery 102 of this embodiment. It is explanatory drawing which shows a performance evaluation result.

A. Embodiment:
A-1. Configuration of all solid state battery 102:
(overall structure)
FIG. 1 is an explanatory view schematically showing a cross-sectional configuration of an all-solid lithium ion secondary battery (hereinafter referred to as “all-solid battery”) 102 in the present embodiment. FIG. 1 shows XYZ axes orthogonal to each other for specifying the direction. In this specification, for convenience, the positive Z-axis direction is referred to as the upward direction, and the negative Z-axis direction is referred to as the downward direction.

  The all-solid-state battery 102 includes a battery main body 110, a positive electrode side current collecting member 154 disposed on one side (upper side) of the battery main body 110, and a negative electrode side current collector disposed on the other side (lower side) of the battery main body 110. A member 156. The positive electrode side current collecting member 154 and the negative electrode side current collecting member 156 are substantially flat plate members having conductivity, for example, stainless steel, Ni (nickel), Ti (titanium), Fe (iron), Cu (copper). , Al (aluminum), a conductive metal material selected from these alloys, a carbon material, or the like. In the following description, the positive electrode side current collecting member 154 and the negative electrode side current collecting member 156 are collectively referred to as a current collecting member.

(Configuration of battery body 110)
The battery body 110 is a lithium ion secondary battery body in which all battery elements are made of solid. The battery body 110 includes a positive electrode 114, a negative electrode 116, and a solid electrolyte layer 112 disposed between the positive electrode 114 and the negative electrode 116. In the following description, the positive electrode 114 and the negative electrode 116 are collectively referred to as electrodes.

(Configuration of solid electrolyte layer 112)
The solid electrolyte layer 112 is a substantially flat plate-like member, and includes a solid electrolyte 122 having lithium ion conductivity. The solid electrolyte 122 included in the solid electrolyte layer 112 is, for example, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, a complex hydride-based solid electrolyte, or a halide-based solid electrolyte. Two or more types may be used.

The oxide-based solid electrolyte includes, for example, a solid electrolyte material having at least Li, La, Zr, and O having a garnet-type crystal structure or a garnet-type similar crystal structure, and at least Li and M (M is Ti, Zr, Ge). (At least one of (germanium)), a solid electrolyte material having a NASICON type structure containing P (phosphorus) and O, and a solid electrolyte having a perovskite type structure containing at least Li, Ti, La and O Any one of the materials, or a mixture of at least two of them. Examples of the solid electrolyte material having the garnet-type crystal structure or the garnet-type similar crystal structure include Li ₇ La ₃ Zr ₂ O ₁₂ (hereinafter referred to as “LLZ”) and Mg (magnesium) and Sr (relative to LLZ). Strontium-substituted elements (hereinafter referred to as “LLZ-MgSr”) or the like can be used. Further, as the solid electrolyte material having the NASICON type structure, for example, Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ (hereinafter referred to as “LAGP”) or the like can be used.

Examples of the sulfide-based solid electrolyte include Li ₂ S—P ₂ S ₅ , Li ₂ S—P ₂ S ₅ —LiI, Li ₂ S—P ₂ S ₅ —Li ₂ O, and Li ₂ S—P. ₂ S ₅ —LiI—Li ₂ O, Li ₂ S—P ₂ S ₅ —LiI—SiS ₂ , Li ₂ S—SiS ₂ , Li ₂ S—SiS ₂ —LiX (where X is I, Br, or Cl _{any), Li 2 S-SiS 2} -LiI-B 2 S 3, Li 2 S-SiS 2 -Li 3 PO 4, Li 2 S-B 2 S 3, Li 2 S-GeS 2, Li 2 S- P ₂ S ₅ —GeS or the like can be used.

As the complex hydride-based solid electrolyte, for _{example, LiBH 4, LiNH 2, LiBH} 4 · 3KI, LiBH 4 · PI 2, LiBH 4 · P 2 S 5, Li 2 AlH 6, Li (NH 2) 2 I 3LiBH ₄ .LiI, Li ₂ NH, LiGd (BH ₄ ) ₃ Cl, Li ₂ (BH ₄ ) (NH ₂ ), Li ₄ (BH ₄ ) (NH ₂ ) _3, or the like can be used. As the halide-based solid electrolyte, for example, LiI, LiBr, LiI-LiBr , LiI-LiCl, Lil-LiF, Li 3 OCl 1-x (OH) x (x = 0~1), Li 2.99 M _0.005 OCl _1-x (OH) _x (M is one of Ba and Ca, x = 0 to 1) and the like can be used.

(Configuration of positive electrode 114)
The positive electrode 114 is a substantially flat plate-like member and includes a positive electrode active material 142. As the positive electrode active material 142, for example, S (sulfur), TiS ₂ , LiCoO ₂ , LiMn ₂ O ₄ , LiFePO ₄ , Li ₄ Ti ₅ O ₁₂ , Li ₂ S, or the like can be used.

The positive electrode 114 includes a specific material 144 that is at least one of a hydrate of lithium halide and a hydroxide of lithium halide. Examples of hydrates of lithium halide include LiI (lithium iodide) hydrate (LiI · H ₂ O), LiBr (lithium bromide) hydrate (LiBr · H ₂ O), and LiCl. A hydrate of (lithium chloride) (LiCl · H ₂ O), a material mainly containing these hydrates of lithium halide (for example, an amorphous body containing lithium iodide), or the like can be used. In addition, in this specification, a main component means the component contained most by volume ratio. Examples of the lithium halide hydroxide include LiI hydroxide (Li ₂ I (OH) and Li ₄ (OH) ₃ I), LiBr hydroxide (Li ₂ Br (OH) and Li ₄ (OH) ₃ Br), LiCl hydroxides (Li ₂ Cl (OH) and Li ₄ (OH) ₃ Cl), and materials mainly composed of these lithium halide hydroxides (for example, lithium iodide water) An amorphous body containing an oxide) or the like can be used. The specific material 144 (at least one of a hydrate of lithium halide and a hydroxide of lithium halide) included in the positive electrode 114 functions as a lithium ion conduction aid, and as described later, the positive electrode 114 and the positive electrode 114 It also functions as an adhesive that secures physical and electrical connection with the side current collecting member 154.

  The positive electrode 114 may contain other lithium ion conduction aids and electron conduction aids (for example, conductive carbon, Ni, Pt (platinum), etc.).

(Configuration of negative electrode 116)
The negative electrode 116 is a substantially flat plate-like member and includes a negative electrode active material 162. As the negative electrode active material 162, for example, Li metal, Li—Al alloy, Li ₄ Ti ₅ O ₁₂ , C (graphite), Si (silicon), Sn (tin), SiO, or the like can be used.

  The negative electrode 116 includes a specific material 164 that is at least one of a hydrate of lithium halide and a hydroxide of lithium halide. As the hydrate of lithium halide and the hydroxide of lithium halide, the same materials as those described above for the positive electrode 114 can be used. The specific material 164 (at least one of lithium halide hydrate and lithium halide hydroxide) included in the negative electrode 116 functions as a lithium ion conduction aid, and as described later, the negative electrode 116 and the negative electrode 116 It also functions as an adhesive that secures physical and electrical connection with the side current collecting member 156.

  Note that the negative electrode 116 may contain other lithium ion conduction aids and electron conduction aids (eg, conductive carbon, Ni, Pt, etc.).

A-2. Manufacturing method of all-solid battery 102:
FIG. 2 is a flowchart showing an example of a method for manufacturing the all solid state battery 102 of the present embodiment. First, a positive electrode precursor for forming the positive electrode 114 and a negative electrode precursor for forming the negative electrode 116 are prepared (S110). The positive electrode precursor is produced, for example, by mixing a powder of the positive electrode active material 142 and a powder of lithium halide (for example, LiI) at a predetermined ratio and molding. The negative electrode precursor is produced, for example, by mixing a negative electrode active material 162 powder and lithium halide (for example, LiI) powder at a predetermined ratio and molding. One of the positive electrode precursor and the negative electrode precursor corresponds to the first electrode precursor in the claims, and the other of the positive electrode precursor and the negative electrode precursor corresponds to the second electrode precursor in the claims. To do. Moreover, the process of S110 is equivalent to the 1st process in a claim.

  Next, using the separately prepared positive electrode side current collecting member 154, solid electrolyte layer 112, and negative electrode side current collecting member 156, the positive electrode side current collecting member 154, the positive electrode precursor, the solid electrolyte layer 112, and the negative electrode precursor And the negative electrode side current collection member 156 is laminated | stacked in this order, and a laminated body is produced (S120). The process of S120 corresponds to the second step in the claims.

  Next, the laminate is humidified while heating (S130). By this heating / humidification treatment, the positive electrode precursor and the negative electrode precursor constituting the laminated body absorb moisture. Here, since the lithium halide has hygroscopicity and deliquescence, the lithium halide contained in the positive electrode precursor and the negative electrode precursor is converted into lithium halide hydrate and / or lithium halide by this heating / humidification treatment. The phase changes to a hydroxide (that is, the specific material 144, 164). As a result of this phase change, the positive electrode precursor becomes the positive electrode 114 including the positive electrode active material 142 and the specific material 144, and the negative electrode precursor becomes the negative electrode 116 including the negative electrode active material 162 and the specific material 164.

  Here, the hydrate of lithium halide and the hydroxide of lithium halide have an adhesion function between substances. Therefore, the lithium halide hydrate and / or lithium halide hydroxide generated in the positive electrode 114 and the negative electrode 116 due to the phase change, between the positive electrode 114 and the positive electrode side current collector 154, and Physical and electrical connection between the negative electrode 116 and the negative electrode side current collecting member 156 is ensured.

  The heating / humidifying treatment time is, for example, preferably 1 hour or longer, more preferably 3 hours or longer, and further preferably 15 hours or longer. The heating temperature is preferably 25 ° C. or more and 200 ° C. or less, and more preferably 70 ° C. or more and 100 ° C. or less. Moreover, you may perform a heating and humidification process in a pressurized state. In this case, the load is preferably 0.1 kN or more, more preferably 0.5 kN or more, and further preferably 1 kN or more. The process of S130 corresponds to the third step in the claims.

  Thereafter, the laminate is naturally cooled to room temperature (S140). Through the above steps, the all-solid battery 102 having the above-described configuration is manufactured.

A-3. Effects of this embodiment:
As described above, the all solid state battery 102 of the present embodiment is disposed between the positive electrode 114 including the positive electrode active material 142, the negative electrode 116 including the negative electrode active material 162, the positive electrode 114 and the negative electrode 116, and lithium ions A solid electrolyte layer 112 including a solid electrolyte 122 having conductivity; a positive electrode side current collecting member 154 disposed on the opposite side of the positive electrode 114 from the solid electrolyte layer 112; and a solid electrolyte layer 112 with respect to the negative electrode 116; Comprises a negative electrode side current collecting member 156 arranged on the opposite side. In the all solid state battery 102 of the present embodiment, the positive electrode 114 and the negative electrode 116 include specific materials 144 and 164 which are at least one of lithium halide hydrate and lithium halide hydroxide. Lithium halide hydrate and lithium halide hydroxide have an adhesion function between substances. Therefore, in the all-solid-state battery 102 of the present embodiment, the physical material between the positive electrode 114 and the positive electrode side current collecting member 154 and between the negative electrode 116 and the negative electrode side current collecting member 156 is determined by the specific materials 144 and 164. Electrical connection is ensured. Therefore, according to the all solid state battery 102 of the present embodiment, a decrease in the electrical performance and heat resistance performance of the all solid state battery 102 due to the use of a polymer binder that does not have ionic conductivity and poor heat resistance is avoided. However, physical and electrical connection between the electrodes 114 and 116 and the current collecting members 154 and 156 can be secured, and the performance of the all-solid-state battery 102 can be improved.

  The physical and electrical connection between the electrodes 114 and 116 and the current collecting members 154 and 156 can be ensured by other methods (for example, a method of separately providing a pressure device, or forming an electronic conductor by sputtering or vapor deposition). For example, a method of baking a current collecting member on the electrode, a method of bonding by melting or softening a current collecting metal substance, and the like. However, in the method of separately providing the pressurizing device, the weight and volume of the pressurizing device are increased, and the energy density of the battery is decreased. In addition, the method of forming the electron conductor by sputtering or vapor deposition increases the cost. Further, in the method of baking the current collecting member on the electrode, since the baking temperature is generally high (about 700 ° C. to 1000 ° C.), materials that can be used as the current collecting member are limited. Further, in the method of joining by dissolving or softening the current collecting metal substance, the cost increases and the materials that can be used as the current collecting member are limited. In the all solid state battery 102 of the present embodiment, physical and electrical connection between the electrodes 114 and 116 and the current collecting members 154 and 156 can be ensured while suppressing the occurrence of these problems.

  Further, the manufacturing method of the all-solid-state battery 102 according to the present embodiment is a positive electrode precursor for forming the positive electrode 114, and includes a positive electrode precursor containing lithium halide and a negative electrode precursor for forming the negative electrode 116. A step of preparing a negative electrode precursor containing lithium halide (S110), a positive electrode precursor, a negative electrode precursor, a solid electrolyte layer 112, a positive electrode side current collecting member 154, and a negative electrode side A step (S120) of laminating the current collecting member 156, and by allowing the positive electrode precursor to absorb moisture, lithium halide contained in the positive electrode precursor is converted to lithium halide hydrate and lithium halide hydroxide; At least one of the specific materials 144, and the lithium halide contained in the negative electrode precursor is converted to lithium halide hydrate and lithium halide hydroxide. And a step (S130) of changing the particular material 164 is at least one of the. In the manufacturing method of the all solid state battery 102 of the present embodiment, the positive electrode precursor and the negative electrode precursor are allowed to absorb moisture, whereby lithium halide contained in the positive electrode precursor and the negative electrode precursor is converted into lithium halide hydrate and halogen. It can be changed to a specific material 144, 164 which is at least one of lithium hydroxide hydroxide. As a result, the positive electrode 114 and the negative electrode 116 can include the specific materials 144 and 164 that are at least one of a hydrate of lithium halide and a hydroxide of lithium halide. Therefore, according to the manufacturing method of the all-solid-state battery 102 of this embodiment, the physical and electrical connection between the electrodes 114 and 116 and the current collecting members 154 and 156 can be ensured.

  In the manufacturing method of the all solid state battery 102 of the present embodiment, moisture absorption of the positive electrode precursor and the negative electrode precursor in the step S130 is performed in a state where the positive electrode precursor and the negative electrode precursor are heated. Therefore, according to the manufacturing method of the all-solid-state battery 102 of this embodiment, it can accelerate | stimulate that the lithium halide contained in a positive electrode precursor and a negative electrode precursor changes to specific material 144,164, and electrode 114, The specific material 144, 164 can be effectively produced in 116. Therefore, according to the manufacturing method of the all-solid-state battery 102 of this embodiment, the physical and electrical connection between the electrodes 114 and 116 and the current collecting members 154 and 156 can be further strengthened. In addition, it is preferable that the temperature of the heating in the process of S130 is 25 degreeC or more and 200 degrees C or less, and it is further more preferable that they are 70 degreeC or more and 100 degrees C or less. In this way, the lithium halide contained in the positive electrode precursor and the negative electrode precursor can be promoted to be changed into the specific materials 144 and 164 by the treatment at a relatively low temperature. The physical and electrical connection between the electrodes 114 and 116 and the current collecting members 154 and 156 can be ensured while suppressing the influence of heat on each member.

  The halogen element in the specific materials 144 and 164 (at least one of lithium halide hydrate and lithium halide hydroxide) preferably contains at least iodine. Lithium halide hydrate containing at least iodine as a halogen element and lithium halide hydroxide have an excellent adhesion function between substances. Therefore, with such a structure, the electrodes 114 and 116 and the current collector are collected. The physical and electrical connection between the members 154 and 156 can be made extremely strong.

A-4. Performance evaluation:
The performance evaluation regarding the physical and electrical connection between the electrode of the all-solid-state battery 102 and the current collecting member was performed. FIG. 3 is an explanatory diagram showing the performance evaluation results.

A-4-1. About Samples As shown in FIG. 3, six samples (S1 to S6) were used for performance evaluation. The method for producing each sample is as follows.

(Preparation of laminate of electrode precursor and current collector)
In a glove box in an argon atmosphere, lithium iodide (LiI) and graphite (C) as an electrode active material were blended in different proportions for each sample, and a zirconia pot (45 cc) and zirconia balls (40 g) were mixed with a planetary ball mill. ) Was mixed and combined at 200 rpm to prepare an electrode material powder. The mixing ratio of sample S1 was 100% graphite (that is, the electrode material powder of sample S1 did not contain LiI). The obtained electrode material powder was press-molded at 360 MPa with a mold having a diameter of 10 mm to produce an electrode precursor. A SUS powder as a current collecting member material was deposited on the electrode precursor, and press-molded again to produce a laminate of the electrode precursor and the current collecting member.

(Preparation of solid electrolyte layer)
_{Composition: Li 1.5 Al 0.5 Ge 1.5 (} PO 4) 3 ( i.e., LAGP) so that _{a, Li 2 CO 3, Al 2} O 3, GeO 2, the _(NH 3) 2 HPO ₄ Weighed with stoichiometric composition. This raw material was put into an alumina pot together with zirconia balls, and pulverized and mixed in an ethanol solvent for 15 hours. After pulverization and mixing, ethanol was volatilized and heat treatment (firing) was performed at 900 ° C. for 2 hours. A ceramic binder was added to the heat-treated sample, and the sample after addition was put into an alumina pot together with zirconia balls, and pulverized and mixed in an ethanol solvent for 15 hours. The sample after pulverization and mixing was dried to volatilize ethanol to obtain a solid electrolyte layer material powder. Next, a solid electrolyte layer material molded body was obtained by applying a hydrostatic pressure of 1.5 t / cm ² to the solid electrolyte layer material powder using a cold isostatic press (CIP). The obtained molded body was subjected to heat treatment (firing) at 850 ° C. for 12 hours to obtain a LAGP sintered body (a disk shape having a diameter of 10 mm and a thickness of 0.5 mm) as a solid electrolyte layer. The relative density of the obtained LAGP sintered body was 97.6%, and the lithium ion conductivity at 25 ° C. was 5.0 × 10 ⁻⁴ S / cm.

(Production of evaluation battery)
A current collector, an electrode precursor, a solid electrolyte layer, and an electrode precursor are brought into contact with both surfaces of a sintered body of LAGP as a solid electrolyte layer by applying a load to the laminate of the electrode precursor and the current collector. And a current collector were laminated in this order. The laminate was sealed in a constant temperature bath at 80 ° C. in an argon atmosphere, and was subjected to a treatment (heating / humidification (moisture absorption) treatment) for 15 hours in a container in which air slightly penetrated. Thereby, LiI contained in each electrode precursor is changed to LiI hydrate and / or hydroxide, and an electrode containing LiI hydrate and / or hydroxide is formed. Then, it naturally cooled to room temperature. The battery of each sample was produced by the above method. However, the heating / humidification (moisture absorption) treatment was not performed when the battery of sample S6 was manufactured.

(Electrode composition)
When the composition of the electrode was examined for the batteries of each sample, as shown in FIG. 3, it was confirmed that the samples S2 to S5 contained LiI hydrate and hydroxide. When this LiI hydrate and hydroxide were specified by XRD analysis, it was confirmed that LiI.H ₂ O, Li ₂ I (OH), and Li ₄ (OH) ₃ I were present. As described above, with respect to sample S1, since the blending ratio of the electrode material powder is 100% graphite (that is, it does not contain LiI), LiI hydrate and / or in the produced electrode of sample S1 Hydroxides were not detected. For sample S6, the electrode material powder blending ratio is the same as that of sample S4, but since heating / humidification (moisture absorption) treatment was not performed, LiI was detected in the electrode, but LiI hydrate and No hydroxide was detected.

  Note that the composition (vol%) of the electrode is specified as follows. That is, the fracture surface substantially orthogonal to the stacking direction of the battery is observed with an SEM, elemental analysis is performed by EDS mapping, and in the field of view, the area where an element (for example, C) contained in the electrode active material is detected, and LiI The ratio of the area where I and O contained in the hydrate and / or hydroxide are simultaneously detected is obtained. Obtain the above-mentioned area ratio in five or more randomly selected cross sections (however, since LiI has deliquescence and tends to gather at the interface, the position of the cross section is 5 μm or more away from the electrode interface) The average value is calculated. Since the composition of the electrode is considered to be approximately uniform, the average value of the area ratio is defined as the volume ratio of the electrode active material and the LiI hydrate and / or hydroxide in the electrode.

A-4-2. Evaluation method (evaluation of physical connection)
In a glove box in an argon atmosphere, one current collecting member of each sample was picked up by tweezers and lifted, and it was confirmed whether or not peeling occurred at the interface between the current collecting member and the electrode due to the weight of the sample. When peeling did not occur, it was judged as good (◯), and when peeling occurred, it was judged as impossible (x). When calculated based on the size of the sample (the bonding surface is a circle having a diameter of 10 mm and the bonding area is 0.785 cm ² ) and the weight (0.57 g), the bonding strength at the interface between the current collecting member and the electrode is 7. peeling if 1 mN / cm ² or more does not occur, the adhesive strength is considered that the peeling is less than 7.1mN / cm ² occurs.

(Evaluation of electrical connection)
The electron / ion conductivity of each sample was measured by an AC impedance method (using Solartron 1470E and 1255B). When resistance is less than 550Ω, it is judged as very good (◎), when resistance is 550Ω or more and less than 650Ω, it is judged as good (◯), and when resistance is 650Ω or more and less than 800Ω (Yes) (Triangle | delta)) and it determined with improper (x) when resistance was 800 ohms or more.

(Comprehensive evaluation)
If at least one of the evaluation for physical connection and the evaluation for electrical connection is determined to be impossible (×), it is comprehensively determined to be impossible (×), and both of the evaluations are determined to be impossible (×). If it is not determined, and it is determined that the electrical connection is evaluated as acceptable (Δ), it is comprehensively determined as acceptable (Δ), and neither of the evaluations is determined as impossible (×). In addition, when it is determined that the electrical connection is very good (◎), it is comprehensively determined as very good (◎), and in all other cases, it is determined as comprehensively good (◯). did.

A-4-3. About Evaluation Results As shown in FIG. 3, in sample S <b> 1, in the evaluation of physical connection, peeling occurred at the interface between the current collecting member and the electrode, and thus it was determined as impossible (×). Further, in the sample S1, in the evaluation of the electrical connection, the resistance was so high that it could not be measured. As a result, the sample S1 was comprehensively determined to be impossible (x). In sample S1, since the electrode does not contain LiI hydrate and / or hydroxide having an adhesion function, physical and electrical connection between the electrode and the current collecting member is not ensured, and the above It is thought that it became the result of.

  Moreover, in sample S6, in the evaluation about physical connection, since peeling occurred at the interface between the current collecting member and the electrode, it was determined to be impossible (x). Further, in sample S6, in the evaluation of the electrical connection, the resistance greatly exceeded 800Ω, so that it was determined to be impossible (×). As a result, it was determined that the sample S6 was totally impossible (x). In sample S6, although the electrode contains LiI but does not contain LiI hydrate and / or hydroxide having an adhesion function, the physical and electrical properties between the electrode and the current collecting member It is probable that the above-mentioned result was obtained because the general connection was not secured.

  On the other hand, in sample S2, in the evaluation about physical connection, since peeling did not occur at the interface between the current collecting member and the electrode, it was determined to be good (◯). Further, in sample S2, in the evaluation of electrical connection, the resistance was 650Ω or more and less than 800Ω, so it was determined to be acceptable (Δ). As a result, the sample S2 was comprehensively determined to be acceptable (Δ). In sample S2, since the electrode contains a small amount of LiI hydrate and / or hydroxide having an adhesion function, physical and electrical connection between the electrode and the current collecting member is ensured. It is thought that the above result was obtained.

  Further, in samples S3 and S5, in the evaluation of physical connection, no peeling occurred at the interface between the current collecting member and the electrode, so that it was determined as good (◯). Moreover, in samples S3 and S5, the resistance was 550Ω or more and less than 650Ω in the evaluation of the electrical connection, so it was determined to be good (◯). As a result, the samples S3 and S5 were determined to be comprehensive (good). In samples S3 and S5, the content ratio of LiI hydrate and / or hydroxide in the electrode is 16 vol% or more and 63 vol% or less, which is higher than the content ratio (8 vol%) of sample S2. It is considered that the electrical connection between the electrode and the current collecting member was good and the above result was obtained.

  Moreover, in sample S4, in evaluation about physical connection, since peeling did not generate | occur | produce in the interface of a current collection member and an electrode, it determined with favorable ((circle)). In addition, in sample S4, the resistance was less than 550Ω in the evaluation of the electrical connection, so it was determined to be very good (（). As a result, the sample S4 was determined to be very good overall (）). In sample S4, the content ratio of LiI hydrate and / or hydroxide in the electrode is 51 vol%, which is not excessively higher than the content ratio of sample S4 (63 vol%). It is considered that the above result was obtained because the decrease in ionic conductivity due to the excessive decrease in the content ratio of the substance could be suppressed. In addition, referring to the evaluation result of sample S4 and the evaluation results of samples S3 and S5, the content ratio of LiI hydrate and / or hydroxide in the electrode is in the range of about 50 vol. % Or more and 60 vol% or less (more preferably, 45 vol% or more and 55 vol% or less), it can be said that a better electrical connection between the electrode and the current collecting member can be secured.

  According to the performance evaluation described above, if the electrode contains a hydrate and / or hydroxide of lithium halide (for example, LiI) (that is, the specific material described above), the electrode and the current collecting member It was confirmed that physical and electrical connections can be secured. In addition, the content ratio of the hydrate and / or hydroxide (specific material) of lithium halide (for example, LiI) in the electrode (generally a negative electrode because graphite was used as an electrode active material in this performance evaluation) It was confirmed that a good electrical connection between the electrode and the current collecting member can be secured when the volume is 16 vol% or more and 63 vol% or less. In addition, the content of lithium halide (for example, LiI) hydrate and / or hydroxide (specific material) in the electrode (negative electrode) is 40 vol% or more and 60 vol% or less (more preferably 45 vol% or more, 55 vol). % Or less), it was confirmed that better electrical connection between the electrode and the current collecting member can be secured.

B. Variation:
The technology disclosed in the present specification is not limited to the above-described embodiment, and can be modified into various forms without departing from the gist thereof. For example, the following modifications are possible.

  The configuration of the all solid state battery 102 in the above embodiment is merely an example, and various changes can be made. For example, in the above embodiment, both the positive electrode 114 and the negative electrode 116 include at least one (specific material) of lithium halide hydrate and lithium halide hydroxide. Only one of 116 may include the specific material. Even in such a configuration, physical and electrical connection between the electrode including the specific material and the current collecting member can be ensured.

  Moreover, the material which forms each member in the said embodiment is an illustration to the last, and each member may be formed with another material.

  Moreover, the manufacturing method of the all-solid-state battery 102 in the said embodiment is an illustration to the last, and the all-solid-state battery 102 may be manufactured by another method. For example, in the above embodiment, in order to change the phase of the lithium halide contained in the electrode precursor into a hydrate of lithium halide and / or a hydroxide of lithium halide, a humidification treatment is performed in a heated state. However, the humidification treatment may be performed without heating. Even in this way, the lithium halide contained in the electrode precursor can be phase-changed to lithium halide hydrate and / or lithium halide hydroxide. Moreover, this humidification process is not necessarily limited to the process of actively supplying moisture, but includes a process of absorbing moisture in the atmosphere.

  In the manufacturing method of the all-solid battery 102 in the above embodiment, the material (raw material) of the electrodes 114 and 116 may be lithium halide hydrate and / or in place of lithium halide or in addition to lithium halide. Alternatively, lithium halide hydroxide may be used. Even in this manner, the electrodes 114 and 116 of the manufactured all-solid-state battery 102 can include a specific material that is at least one of lithium halide hydrate and lithium halide hydroxide.

 In the above embodiment, the all-solid-state battery 102 is targeted. However, the configuration of the present application is another lithium battery that uses a solid electrolyte material having lithium ion conductivity (for example, a lithium-air battery or a lithium flow battery). It is also applicable to. Further, the structure of the lithium battery may be a flat plate structure or a wound structure.

102: All-solid-state lithium ion secondary battery 110: Battery body 112: Solid electrolyte layer 114: Positive electrode 116: Negative electrode 122: Solid electrolyte 142: Positive electrode active material 144: Specific material 154: Positive electrode side current collecting member 156: Negative electrode side current collector Member 162: Negative electrode active material 164: Specific material

Claims (10)

A positive electrode including a positive electrode active material;
A negative electrode containing a negative electrode active material;
A solid electrolyte layer disposed between the positive electrode and the negative electrode and including a solid electrolyte having lithium ion conductivity;
A positive electrode side current collecting member disposed on the opposite side of the solid electrolyte layer with respect to the positive electrode;
A negative electrode side current collecting member disposed on the opposite side of the solid electrolyte layer with respect to the negative electrode;
In a lithium battery comprising:
At least one of the said positive electrode and the said negative electrode contains the specific material which is at least one of the hydrate of lithium halide, and the hydroxide of lithium halide, The lithium battery characterized by the above-mentioned. The lithium battery according to claim 1,
The lithium battery is characterized in that a content ratio of the specific material in the negative electrode is 16 vol% or more and 63 vol% or less. The lithium battery according to claim 2,
The lithium battery is characterized in that the content ratio of the specific material in the negative electrode is 40 vol% or more and 60 vol% or less. In the lithium battery according to any one of claims 1 to 3,
The lithium battery, wherein the halogen element of the lithium halide contains at least iodine. A positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, a solid electrolyte layer disposed between the positive electrode and the negative electrode and including a solid electrolyte having lithium ion conductivity, and the solid with respect to the positive electrode In a method for producing a lithium battery, comprising: a positive electrode side current collecting member disposed on the side opposite to the electrolyte layer; and a negative electrode side current collecting member disposed on the side opposite to the solid electrolyte layer with respect to the negative electrode.
A first electrode precursor for forming one of the positive electrode and the negative electrode, the first electrode precursor containing lithium halide, and the other of the positive electrode and the negative electrode A first step of preparing a second electrode precursor of
A second step of laminating the first electrode precursor, the second electrode precursor, the solid electrolyte layer, the positive electrode side current collecting member, and the negative electrode side current collecting member;
Specification that the lithium halide contained in the first electrode precursor is at least one of a hydrate of lithium halide and a hydroxide of lithium halide by causing the first electrode precursor to absorb moisture A third step of changing to a material;
A method for producing a lithium battery, comprising: In the manufacturing method of the lithium battery according to claim 5,
The method for producing a lithium battery, wherein moisture absorption of the first electrode precursor in the third step is performed in a state where the first electrode precursor is heated. In the manufacturing method of the lithium battery according to claim 5 or 6,
The second electrode precursor contains lithium halide;
In the third step, the lithium halide contained in the second electrode precursor is hydrated with lithium halide and the hydroxide of lithium halide by causing the second electrode precursor to absorb moisture. A method for producing a lithium battery, comprising changing to a specific material. In the manufacturing method of the lithium battery according to claim 7,
The method for producing a lithium battery, wherein moisture absorption of the second electrode precursor in the third step is performed in a state where the second electrode precursor is heated. In the manufacturing method of the lithium battery according to claim 6 or 8,
The method for producing a lithium battery, wherein the temperature in the heated state in the third step is 25 ° C. or higher and 200 ° C. or lower. In the manufacturing method of the lithium battery as described in any one of Claim 5- Claim 9,
The method for producing a lithium battery, wherein the halogen element of the lithium halide contains at least iodine.

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