JP2009123389A - All-solid secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an all-solid secondary battery that is easy to manufacture and of a simple structure. <P>SOLUTION: The all-solid secondary battery 10 capable of multiple valence changes includes a single-layer active material layer 12 including an active material 32 that has different redox potentials for respective valence changes, a positive electrode collector electrode 14 arranged on one surface of the single-layer active material layer 12, and a negative electrode collector electrode 16 arranged on the other surface of the single-layer active material layer 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an all solid state secondary battery. More specifically, the present invention relates to an all-solid-state secondary battery that is simple to manufacture and has a simpler configuration.

  In recent years, with the development of portable devices such as personal computers and mobile phones, the demand for batteries as power sources has been greatly expanded. In a battery used for such an application, a liquid electrolyte (electrolytic solution) such as a flammable organic solvent is conventionally used as a diluent solvent as a medium for moving ions. In a battery using such an electrolytic solution, problems such as ignition and explosion may occur due to leakage of the electrolytic solution.

  In order to solve these problems, in order to ensure intrinsic safety, solid electrolytes are used in place of liquid electrolytes, and development of all-solid-state batteries in which all other elements are composed of solids has been promoted. Yes. Since such an all-solid battery is formed of sintered ceramics whose electrolyte is a solid, there is no concern of ignition or leakage, and problems such as deterioration of battery performance due to corrosion are unlikely to occur. . In particular, all-solid lithium secondary batteries have been actively studied in various fields as secondary batteries that can easily have a high energy density (see, for example, Patent Document 1).

  A conventional battery is composed of three layers: a positive electrode active material layer made of a positive electrode active material and a negative electrode active material layer made of a negative electrode active material, and an electrolyte layer that electrically insulates these electrodes and has only ionic conductivity. ing. And this laminated body is an internal electrode body of an all-solid-state battery. Regarding the manufacturing method, an all solid state battery is manufactured by laminating these three layers by various methods. For example, in the case of a cylindrical cell using a liquid electrolyte, the wound internal electrode body can be manufactured by winding the sheet having the three-layer structure into a cylindrical shape.

  In such a conventional battery, since the positive electrode active material layer and the negative electrode active material layer are made of different materials, the above-described complicated three-layer structure must be formed using three types of materials. In other words, there is a problem that the manufacturing process is complicated.

  For this reason, an all-solid battery using an electrode active material that can be used for both a positive electrode and a negative electrode has been proposed (see, for example, Patent Document 2).

JP-A-5-205741 JP 2007-258165 A

  Since the electrode active material used in the all solid state battery of Patent Document 2 can be used for both the positive electrode and the negative electrode as described above, the same kind of electrode active material is used on both sides of the layer made of the solid electrolyte. By forming each active material layer made of an active material, an all-solid battery having a high output and a long life can be obtained. Thus, the all-solid-state battery of Patent Document 2 has a simple material configuration because only one type of electrode active material is required.

  However, the structural configuration of the all-solid battery remains the same as the three-layer structure of the positive electrode active material layer, the electrolyte layer, and the negative electrode active material layer, and a complicated three-layer structure must be formed. The problem was not solved.

  That is, even if an active material that can be used for both the positive electrode and the negative electrode is used, as long as the structure of the battery is the above three-layer structure, even if a liquid electrolyte is used, Even if it is a case where it uses, it does not lead to reduction of the number of processes on manufacture. For this reason, development of a battery with a simpler configuration that is simple to manufacture is required.

  The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide an all-solid-state secondary battery that is simple to manufacture and has a simpler configuration. .

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have changed to a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer having a three-layer structure, such as a conventional battery, The present inventors have found that the above-described problems can be achieved by using a single-layer active material layer including a single layer containing an active material that can be an electrode for each of the negative electrodes, and have completed the present invention.

  That is, according to the present invention, the following all-solid secondary battery is provided.

[1] A single-layer active material layer composed of a single layer including active material materials capable of changing a plurality of valences and having different redox potentials corresponding to the valence changes, and one of the single-layer active material layers An all solid state secondary battery comprising: a positive electrode collector electrode disposed on a surface; and a negative electrode collector electrode disposed on the other surface of the single-layer active material layer.

[2] The all-solid-state secondary battery according to [1], wherein the single-layer active material layer further includes a solid electrolyte.

[3] The all-solid-state secondary battery according to [2], wherein the active material and the solid electrolyte are phosphoric acid compounds each having a NASICON structure or an olivine structure.

[4] All of the above [3], wherein the single layer active material layer is obtained by heating and firing a precursor of a single layer active material layer containing a solid electrolyte material made of an amorphous phosphate compound. Solid secondary battery.

[5] The all solid state secondary battery according to any one of [2] to [4], wherein the solid electrolyte is a phosphoric acid compound represented by the following general formula (1).
_{Li 1 + y Al y Ge 2} -y (PO 4) 3 (1)
(In the general formula (1), y is 0 ≦ y ≦ 1)

[6] The all solid state secondary battery according to any one of [1] to [5], wherein the active material is a phosphate compound represented by the following general formula (2).
Li _x V ₂ (PO ₄ ) ₃ (2)
(In the above general formula (2), x is 1 ≦ x ≦ 5)

  Since the all-solid-state secondary battery of the present invention does not require an electrode body constituted by a complicated laminated structure as an internal electrode body, it is easy to manufacture and has a simple structure. Since the all-solid-state secondary battery of the present invention includes an active material layer composed of a single layer as the internal electrode body, the internal resistance of the all-solid-state secondary battery can be reduced. Further, since no electrolyte layer is required for the internal electrode body, the battery can be made smaller and thinner.

  Furthermore, in the all-solid-state secondary battery of the present invention, by including a solid electrolyte in the single-layer active material layer, for example, when the ionic conductivity of the active material itself used is poor (that is, the rate characteristics are poor). Even if it exists, it can be set as the all-solid-state secondary battery with a high rate characteristic by assisting the ionic conductivity of a single layer active material layer.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiments, and the ordinary knowledge of those skilled in the art is within the scope of the present invention. Based on the above, it should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

[1] All-solid secondary battery:
First, an embodiment of the all solid state secondary battery of the present invention will be described. As shown in FIG. 1, the all-solid-state secondary battery of this embodiment includes a single layer including an active material 32 that can change a plurality of valences and has different redox potentials corresponding to each valence change. A single-layer active material layer 12, a positive electrode collector electrode 14 disposed on one surface of the single-layer active material layer 12, and a negative electrode collector electrode 16 disposed on the other surface of the single-layer active material layer 12. This is an all-solid secondary battery 10 provided.

  The active material having a different redox potential corresponding to each of the valence changes described above can be used as, for example, an active material that can serve as a positive electrode and a negative electrode in a conventional secondary battery. It is a material.

  Here, FIG. 1 is a schematic diagram illustrating the configuration of an embodiment of the all solid state secondary battery of the present invention. 1 shows a state in which the all-solid-state secondary battery is cut along a plane perpendicular to the surface of the single-layer active material layer.

  The all-solid-state secondary battery according to the present embodiment does not require an electrode body configured by a complicated laminated structure as an internal electrode body, and includes a single-layer active material layer composed of a single layer as an internal electrode body. There is no new all-solid-state battery. The all solid state secondary battery of the present embodiment is simple to manufacture and has a simple configuration. In addition, since an electrolyte layer serving as a partition between the positive electrode active material layer and the negative electrode active material layer is not required, the battery can be reduced in size and thickness.

  In addition, in the case of a battery having a three-layer structure of a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer as in a conventional all solid state battery, a technique for satisfactorily joining the interfaces of the three layers is required. Become. Specifically, it is important that the interface is well connected in terms of structure. In other words, in a battery, electrons and ions are exchanged in structurally connected parts. However, in the case of an all-solid battery, if the joint between particles is in a state such as point contact, the part is very Since the resistance is high, the battery has high internal resistance and poor performance. For this reason, the bonding between the particles is required to be performed in a wider area.

  In addition, in the conventional all-solid battery, as described above, bonding at the interface between the three layers is important, but since different materials such as the active material and the solid electrolyte are in contact with each other, the reactivity between the materials is also questioned. . Specifically, at the temperature at which the material sinters, for example, a heterogeneous phase is formed at the interface between the active material and the solid electrolyte, which becomes a high resistance layer, or the composition of the active material changes to charge / discharge the theoretical capacity. It may become impossible to cause deterioration of battery performance.

  Therefore, in the structure of a conventional three-layer all-solid battery in which a combination of an active material and a solid electrolyte that avoids a reaction between such materials must be compatible with a plurality of combinations on the positive electrode side and the negative electrode side, There were few choices of materials suitable for combination, making it difficult to put it into practical use.

  An all-solid-state secondary battery according to an embodiment of the present invention includes a single-layer active material layer that includes the above-described specific active material, that is, a single layer including an active material that can be a positive electrode and a negative electrode. Therefore, unlike the above three-layer structure, there is no problem due to poor bonding at each interface, and a battery with low internal resistance can be obtained. It is also possible to suppress formation of a layer such as a solid electrolyte interface that may deteriorate battery performance.

  In the all-solid-state secondary battery of this embodiment, the single-layer active material layer, which is a single layer, constitutes the internal electrode body in the conventional battery. Before), the potential of the all-solid-state secondary battery is zero. For this reason, storage for a longer period of time becomes possible. In order to ensure safety, a liquid secondary battery on the market has a protection circuit with a program that forcibly prohibits subsequent charging / discharging when the voltage falls outside the specified voltage range. It is common. Under such circumstances, when the secondary battery is shipped and stored in a fully charged state, there is a disadvantage that the deterioration of the electrolytic solution is likely to proceed quickly and self-discharge is also facilitated. On the other hand, when the secondary battery is shipped and stored in a discharged state, the voltage drops due to self-discharge, and the above-described protection circuit is activated. For this reason, in order to eliminate the above inconvenience, the secondary battery is generally shipped and stored in a half-charged state so that it is in the vicinity of an intermediate potential within a predetermined voltage frame.

  Since the all-solid-state secondary battery of this embodiment has a symmetric structure, the state immediately after manufacture is in a discharged state (voltage = 0 V), and can be shipped and stored in that state. For this reason, the problem of electrode elution due to overdischarge, which was a weak point of a lithium battery, does not occur, and long-term storage is possible.

  In addition, the all-solid-state secondary battery of this embodiment is a highly safe battery because all the constituent elements thereof are solid, so that problems such as battery performance deterioration due to leakage or corrosion hardly occur.

  In the all-solid-state secondary battery according to another embodiment of the present invention, the single-layer active material layer 22 may further include a solid electrolyte 34 as shown in FIG. That is, a single-layer active material layer 22 including a single layer including an active material 32 having a different redox potential corresponding to each valence change, and a solid electrolyte 34, and the single layer This is an all-solid-state secondary battery 20 including a positive electrode collector electrode 14 disposed on one surface of the active material layer 22 and a negative electrode collector electrode 16 disposed on the other surface of the single layer active material layer 22. Here, FIG. 2 is a schematic diagram illustrating the configuration of another embodiment of the all solid state secondary battery of the present embodiment.

  By further containing the solid electrolyte in this way, for example, even when the ionic conductivity of the active material material itself used is poor (that is, the rate characteristics are poor), the solid electrolyte allows the single-layer active material layer to By assisting ionic conductivity, an all-solid secondary battery with high rate characteristics can be obtained. However, it goes without saying that the solid electrolyte selected is a combination of materials that can avoid the reaction between the materials at the sintering temperature. For example, the solid electrolyte is made amorphous for the purpose of lowering the sintering temperature and avoiding the reaction. It is preferable to use a solid electrolyte or the like.

[1-1] Single layer active material layer:
The single-layer active material layer 12 used in the all-solid-state secondary battery 10 of this embodiment as shown in FIG. 1 is a single layer including at least the specific active material 32 described above. This single-layer active material layer 12 is, for example, a chargeable / dischargeable secondary battery such as an internal electrode body in which a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer in a conventional all-solid battery are stacked. Functions as an internal electrode body.

  Such a single-layer active material layer has high ionic conductivity, but has a lower electronic conductivity than the ionic conductivity. The movement of ions from one side to the other surface side is relatively free.

  On the contrary, since the movement of electrons is performed only in a relatively narrow range on each surface side, one surface side and the other surface side in the single layer active material layer are respectively in the conventional internal electrode body. A portion that performs the same function as the positive electrode active material layer and the negative electrode active material layer and does not move electrons (specifically, an intermediate portion in the thickness direction of the single layer active material layer) It functions as a solid electrolyte layer in the electrode body, that is, a layer that allows only ions to pass without passing electrons.

  Since the active material layer is formed using an active material having both the characteristics of the positive electrode and the negative electrode, even if the internal electrode body is only a single active material layer, The secondary battery can realize the operation as a battery.

  For this reason, the single-layer active material layer of the all-solid-state secondary battery of the present embodiment has characteristics that can be used as the positive electrode and the negative electrode, has high ionic conductivity, and has electrons compared to ionic conductivity. It is preferable that the conductivity is lower.

  As such an active material, for example, a phosphoric acid compound having a NASICON (Na Super Ionic Conductor) structure can be cited as a preferred example.

More specifically, the active material is preferably a phosphoric acid compound represented by the following general formula (2).
Li _x V ₂ (PO ₄ ) ₃ (2)
(In the above general formula (2), x is 1 ≦ x ≦ 5)

  Such a phosphoric acid compound can change a plurality of valences and has different redox potentials corresponding to each valence change, and thus can be used as a battery having a voltage utilizing the different redox potential differences (for example, S. Okada DENKI KAGAKU vol. 65 P802 (1997)).

Li ₃ V ₂ (PO ₄ ) ₃ can change the valence of V ^{3 + / 2 +} , V ^{2 + / 1 +} , V ^{3 + / 4 +} , V ^{4 + / 5 +} around the trivalent state of V, respectively. It is a material having the characteristic of having different redox potentials. In addition, it is disadvantageous if it is inherently low in electronic conductivity compared to a general oxide-based active material, but the present invention has an advantage characterized by this point.

Examples of other suitable active materials include Li _a VPO ₄ F and Na _a VPO ₄ F (wherein a is 0 ≦ a ≦ 1), and Na _b V ₂ (PO _{4 3} (in the general formula, b is 1 ≦ b ≦ 5) and the like.

  In the all solid state secondary battery of the present invention, as shown in FIG. 2, the single-layer active material layer 22 may further include a solid electrolyte 34. The content of such a solid electrolyte 34 can be appropriately adjusted according to the value of ion conductivity of the active material 32 contained in the single-layer active material layer 22. By comprising in this way, even if it is a case where the ionic conductivity of the active material material 32 itself to be used is poor (namely, rate characteristics are bad), the ionic conductivity of the single layer active material layer 22 is assisted, It can be set as the all-solid-state secondary battery 20 with a high rate characteristic.

  In such an all-solid secondary battery, there are no particular restrictions on the types of active material and solid electrolyte material, but a phosphoric acid compound having a NASICON structure is preferred. By configuring in this way, both materials have a common polyanion skeleton structure, and can have a vertex shared skeleton structure that shares the vertices of each, so that ions move more smoothly at the junction interface between the two materials. It becomes possible.

  In addition, it is preferable that a single layer active material layer is a thing formed by heat-firing the precursor of the single layer active material layer containing the solid electrolyte material which consists of an amorphous phosphoric acid compound. In addition, the precursor of a single layer active material layer is the unbaking molded object which shape | molded the raw material containing the said active material material and solid electrolyte material in the shape of the single layer active material layer. By comprising in this way, sintering of solid electrolyte advances at the time of heat-firing, and it becomes possible to form more joint interface areas with an active material material.

More specifically, the solid electrolyte is preferably a phosphoric acid compound represented by the following general formula (1).
_{Li 1 + y Al y Ge 2} -y (PO 4) 3 (1)
(In the general formula (1), y is 0 ≦ y ≦ 1, more preferably 0.3 ≦ y ≦ 0.7)

  The single-layer active material layer is formed in a layered form (thin film form). For example, one surface side becomes a positive electrode (or negative electrode) and the other surface side becomes a negative electrode (or positive electrode). The thickness of the single-layer active material layer is not particularly limited, but it depends on the required battery capacity. However, when the current rate to be taken out is set to be high, it should be as thin as possible, for example, 5 μm to 1 mm. Is preferably about 5 to 50 μm. By comprising in this way, the internal resistance of a battery can be reduced and battery performance can be improved.

  In addition, there is no restriction | limiting in particular about the mixing ratio of the active material material which comprises a single layer active material layer, and a solid electrolyte material, It can determine suitably with the battery capacity required and the electric current rate to extract.

[1-2] Positive electrode collector and negative electrode collector:
The positive electrode collector electrode is a collector electrode disposed on one surface of the single-layer active material layer, and is electrically connected to one surface of the single-layer active material layer. The negative electrode collector electrode is a collector electrode disposed on the other surface of the single layer active material layer (the surface opposite to the one surface) and is electrically connected to the other surface of the single layer active material layer Has been.

  In the all solid state secondary battery of this embodiment, charging and discharging of the single layer active material layer can be performed by the positive electrode collector electrode and the negative electrode collector electrode. As such a positive electrode collector electrode and a negative electrode collector electrode, what was comprised similarly to the collector electrode in a conventionally well-known all-solid-state battery can be used, for example.

  In addition, as a material which comprises the positive electrode collector electrode and negative electrode collector electrode which are used for the all-solid-state secondary battery of this embodiment, for example, platinum (Pt), platinum (Pt) / palladium (Pd), gold (Au), Common electron conductive metal materials such as silver (Ag), aluminum (Al), copper (Cu), ITO (indium-tin oxide film), and SUS plate can be given.

  In the all solid state secondary battery of the present embodiment, a single layer active material layer having a certain thickness from the surface on which the positive electrode collector electrode and the negative electrode collector electrode are arranged is the positive electrode active material layer and the negative electrode active material layer in the conventional all solid battery. Since it functions as a material layer, the capacity of the all-solid-state secondary battery can be increased as the area where the positive electrode collector and the negative electrode collector are arranged is larger. For this reason, it is preferable that the positive electrode collector electrode and the negative electrode collector electrode are disposed over the entire surface of each single-layer active material layer.

  The thickness of the positive electrode collector and the negative electrode collector is not particularly limited as long as charging and discharging of the all-solid-state secondary battery can be performed by the positive electrode collector and the negative electrode collector. Since the all-solid-state secondary battery of this embodiment can implement | achieve a thin secondary battery, it is preferable that it is a thin film about several micrometers, for example.

  The positive electrode collector and the negative electrode collector are, for example, a sputtering method, a resistance heating evaporation method in which an evaporation source is heated by resistance, an ion beam evaporation method in which the evaporation source is evaporated by heating with an ion beam, and an evaporation source by an electron beam. The single layer active material layer can be disposed on each surface by a method such as an electron beam vapor deposition method in which the material is heated and deposited. In addition, when the all solid state secondary battery of this embodiment is accommodated in a case or the like, insulation between the positive electrode collector electrode and the negative electrode collector electrode is ensured.

[2] Method for producing all-solid secondary battery:
Next, the manufacturing method of the all-solid-state secondary battery of this invention is demonstrated. When manufacturing the all solid state secondary battery of the present invention, first, a single layer active material layer using an active material having a plurality of valence changes and having different redox potentials corresponding to each valence change. Is made. Specifically, a plurality of valence changes are possible, and powders of active material materials having different redox potentials corresponding to the respective valence changes are placed in a mold or the like and pressed, and a single layer active material having a desired thickness is pressed. The precursor of the material layer is formed. Alternatively, a method in which a slurry made of an active material is prepared using a binder or an organic solvent, and a sheet is formed by a doctor blade method, a reverse roll coater method, or the like is preferably employed. Note that when a single-layer active material layer containing an active material and a solid electrolyte material is produced, a powder obtained by mixing the active material and the solid electrolyte material is used in the same manner as described above. To mold the precursor of the single layer active material layer.

  Next, the obtained single layer active material layer precursor is fired to produce a single layer active material layer. By firing in this way, the connection part (necking) between the particles of the active material or the solid electrolyte can be made favorable.

  The firing conditions vary depending on the active material used and the type of the solid electrolyte material, but in order to obtain a sufficient connecting portion (necking), the temperature at which the used material can be sintered, that is, the active material. In the case where the active material is formed only by the temperature, the active material can be sintered at a temperature, or in the case of a mixed layer, any material can be sintered at a temperature, and the quality change due to the reaction between the materials. Firing is preferably performed at a temperature that does not occur.

  Next, collector electrodes (a positive electrode collector electrode and a negative electrode collector electrode) are disposed on one surface and the other surface of the obtained single-layer active material layer. As a material constituting the positive electrode collecting electrode and the negative electrode collecting electrode, the above-described metals are arranged by, for example, a sputtering method or the like. In this way, the all solid state secondary battery of the present invention can be manufactured.

  Moreover, it is good also as a product shape of an all-solid-state secondary battery by coat | covering the outer periphery of the side wall of the obtained all-solid-state secondary battery by molding with resin or glass material.

[3] All-solid-state secondary battery unit:
Next, an all solid state secondary battery unit which is still another embodiment of the all solid state secondary battery of the present invention will be described. The all-solid-state secondary battery unit of the present embodiment is configured by stacking a plurality of single-layer active material layers, which have been described so far, electrically in series via a current collector. All-solid-state secondary battery unit.

  That is, as shown in FIG. 3, the all-solid-state secondary battery unit of the present embodiment is capable of changing a plurality of valences, and an active material 32 having different redox potentials corresponding to each valence change, that is, A laminate in which a plurality of single-layer active material layers 42 including a single layer containing an active material that can serve as the positive electrode and the negative electrode are stacked in series via a collector electrode 48 ( Hereinafter, it is an all-solid-state secondary battery unit 40 (all-solid-state secondary battery) having a “single-layer active material layer laminate 50”, and one single-layer active material layer 42 becomes a single cell of the battery. It is a battery unit configured by stacking a plurality of single cells.

  In the all-solid-state secondary battery unit 40, a plurality of energizing collector electrodes 48 for energizing adjacent single-layer active material layers 42 in the single-layer active material layer stack 50, and the single-layer active material layer stack 50. Positive electrode collector electrode 44 arranged on one surface (one outermost surface) and a negative electrode collector electrode 46 arranged on the other surface (the other outermost surface).

  Here, FIG. 3 is a schematic diagram illustrating the configuration of an all solid state secondary battery unit which is still another embodiment of the all solid state secondary battery of the present invention.

  Such an all-solid-state secondary battery unit can generate a high potential that is difficult to achieve with a single-cell all-solid-state secondary battery, and the number of single-layer active material layer stacks stacked via a current collector Thus, the required potential (high potential) can be secured. In particular, the all-solid-state secondary battery of the present invention uses an active material layer that can be thinned, which is a single-layer active material layer, so that the entire thickness of the all-solid-state secondary battery unit can be reduced. .

  FIG. 3 shows an all solid state secondary battery unit 40 in which five single-layer active material layers 42 are stacked so as to be electrically in series via a current collecting electrode 48. There is no restriction | limiting in particular about the number of single layer active material layers.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

Example 1
A powder obtained by mixing a specific active material that can be used as either a positive or negative electrode and a solid electrolyte so as to have a mass ratio of 1: 1 is compacted at a pressing force of about 500 kg / cm ² . Then, a pellet (a single layer active material layer precursor) having a diameter of about 15.5 mm and a thickness of 1 mm after firing was formed. The pellet was heated up to 600 ° C. at a temperature increase rate of 200 ° C./hr in an Ar atmosphere, kept for 40 hours, and then cooled down at 200 ° C./hr (to cool down by allowing to cool in a range where temperature does not follow) And fired to prepare a single layer active material layer.

Note that LVP: Li ₃ V ₂ (PO ₄ ) ₃ was used as the active material, and LAGP: Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ was used as the solid electrolyte.

Next, gold (Au) is sputtered on both surfaces of the single layer active material layer obtained by the main firing (the area of one surface is about 1.89 cm ² ), and the positive electrode has a thickness of about 500 angstroms. A collector electrode and a negative electrode collector electrode were formed to produce an internal electrode body.

  The internal electrode body thus obtained was heat-dried in a vacuum (130 ° C., overnight) and then incorporated into a CR2032-type coin battery in a glove box in an inert atmosphere. (Example 1) was manufactured.

[Evaluation of Charging / Discharging Characteristics]: The obtained all-solid-state secondary battery was charged and discharged by a CCCV (Constant Current Constant Voltage) method, and the charging / discharging evaluation of the all-solid-state secondary battery was performed. Specifically, the charging characteristics, was charged at a constant current 5 .mu.A / cm ² to 2.4V cutoff capacity when charged at 2.4V constant voltage until the current value of 0.5μA / cm ² (μAh ) Was measured. The discharge characteristics measured and was discharged at a constant current of 5 .mu.A / cm ² to 0.1V cutoff discharge capacity when discharged at 0.1V constant voltage until the current value of 0.5μA / cm ² (μAh) did. Charging and discharging were performed for a total of two cycles.

  FIG. 4 is a graph showing the evaluation results of the evaluation of the charge / discharge characteristics of the all-solid-state secondary battery in Example 1. In FIG. 4, the vertical axis represents voltage (V) during charging and discharging, and the horizontal axis represents capacity (μAh) (discharge capacity (μAh) during discharging). In addition, the thin line in a graph shows the result in the 1st charge / discharge, and the thick line shows the result in the 2nd charge / discharge.

  [AC Impedance]: AC impedance was measured using a combination of Solartron 1287 type potentio / galvanostat (trade name) and 1255B type frequency response analyzer (trade name). The measurement frequency was 1 MHz to 0.1 Hz, and measurement was performed at a measurement signal voltage of 10 mV.

  FIG. 5 is a graph showing an AC impedance waveform of the all-solid-state secondary battery in Example 1. FIG. 5 is a graph in which data obtained by AC impedance measurement is plotted separately for a real component and an imaginary component. The vertical axis represents the imaginary part of impedance (Ω), and the horizontal axis represents the real part of impedance (Ω). According to this, the intragranular resistance of about 1 kΩ from the real axis side intercept on the high frequency side (1 MHz side) corresponding to the arc from 1 MHz to 1 kHz, and about 4 kΩ from the real axis side intercept corresponding to the arc from 1 MHz to 1 kHz. It can be seen that the battery has an internal resistance formed by an intergranular resistance and an interfacial reaction resistance of about 8 kΩ from the section on the real axis side corresponding to the arc on the low frequency side. From this result, it was confirmed that the all-solid-state secondary battery of Example 1 was not a configuration like a simple capacitor but a secondary battery using ionic conduction (chemical reaction).

From the above results, it was confirmed that the all solid state secondary battery of Example 1 was a secondary battery capable of being charged and discharged. As a result of charging and discharging, a discharge capacity of about 30 μAh was confirmed at a current rate of 0.5 μA / cm ² . When the theoretical capacity of LVP is converted to about 130 mAh / g, the mass of the active material used in this battery was 182.4 mg, so that it can be used as an electrode on one side, so that the theory of the battery The capacity is about 12 mAh. Therefore, since charging / discharging is performed with an active material of about 0.25%, when converted from a battery thickness of 1 mm, the active material from the collector electrode to a depth of about 2.5 μm is used.

For example, since the all solid state secondary battery of Example 1 has a discharge capacity of about 10 μAh at a current rate of 5 μA / cm ² , an active material from the current collection to a depth of 0.8 μm was used at this rate. It becomes calculation. Thus, since the depth which can be used is decided by the target current rate, a more efficient battery can be manufactured by determining the thickness of the battery therefrom.

  The all-solid-state secondary battery of the present invention is a battery (hybrid) used in combination with other batteries such as a battery for portable devices, a battery for built-in IC card, a battery for implant medical device, a battery for surface mounting of a substrate, and a solar battery. It is also suitable as a power source battery.

It is a schematic diagram explaining the structure of one Embodiment of the all-solid-state secondary battery of this invention. It is a schematic diagram explaining the structure of other embodiment of the all-solid-state secondary battery of this invention. It is a schematic diagram explaining the structure of the all-solid-state secondary battery unit which is further another embodiment of the all-solid-state secondary battery of this invention. 4 is a graph showing an evaluation result of evaluation of charge / discharge characteristics of an all-solid secondary battery in Example 1. 3 is a graph showing an AC impedance waveform of the all-solid-state secondary battery in Example 1.

Explanation of symbols

10: all solid state secondary battery, 12: single layer active material layer, 14: positive electrode current collector, 16: negative electrode current collector, 20: all solid state secondary battery, 22: single layer active material layer, 32: active material, 34: solid electrolyte, 40: all solid state secondary battery (all solid state secondary battery unit), 42: single layer active material layer, 44: positive electrode collector electrode, 46: negative electrode collector electrode, 48: collector electrode (collector electrode for energization) ), 50: Single layer active material layer laminate.

Claims (6)

A single-layer active material layer comprising a single layer including an active material having a plurality of valence changes, each having a different redox potential corresponding to each valence change;
A positive electrode collector electrode disposed on one surface of the single-layer active material layer;
An all-solid-state secondary battery comprising: a negative electrode collector electrode disposed on the other surface of the single-layer active material layer.   The all-solid-state secondary battery according to claim 1, wherein the single-layer active material layer further includes a solid electrolyte.   The all solid state secondary battery according to claim 2, wherein the active material and the solid electrolyte are phosphoric acid compounds each having a NASICON structure or an olivine structure.   The all-solid-state secondary battery according to claim 3, wherein the single-layer active material layer is obtained by heating and firing a precursor of a single-layer active material layer containing a solid electrolyte material made of an amorphous phosphate compound. . The all-solid-state secondary battery according to any one of claims 2 to 4, wherein the solid electrolyte is a phosphoric acid compound represented by the following general formula (1).
_{Li 1 + y Al y Ge 2} -y (PO 4) 3 (1)
(In the general formula (1), y is 0 ≦ y ≦ 1) The all-solid-state secondary battery according to any one of claims 1 to 5, wherein the active material is a phosphoric acid compound represented by the following general formula (2).
Li _x V ₂ (PO ₄ ) ₃ (2)
(In the above general formula (2), x is 1 ≦ x ≦ 5)

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