JP2009032597A - Lithium battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithium battery where a positive electrode layer is less likely to be removed from a positive current collector according to charge discharge of the battery. <P>SOLUTION: The lithium battery 1 is formed by laminating an interposed layer 12, a positive electrode layer 13, an SE layer 14, and a negative electrode layer 15 in order on a positive current collector 11. The interposed layer 12 is arranged between the positive current collector 11 and the positive electrode layer 13 to enhance adhesion therebetween. The interposed layer 12 is composed of an oxide of a metal element contained in the positive current collector 11 when an active material of the positive electrode layer 13 is composed of an oxide, and composed of a sulfide of the metal element when the active material of the positive electrode layer is composed of a sulfide. By selecting the composition of the interposed layer 12 like this, the interposed layer 12 having high adhesion to the positive current collector 11 and also to the positive electrode layer 13 can be obtained. As a result, the lithium battery is less likely to be removed from the positive electrode layer according to the charge and discharge of the battery can be obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an all-solid-state lithium battery having a solid electrolyte layer, which relates to a lithium battery in which adhesion between a positive electrode current collector and a positive electrode layer is improved.

  A lithium battery includes a negative electrode layer formed on a negative electrode current collector (the negative electrode layer may also serve as the negative electrode current collector), a positive electrode layer formed on the positive electrode current collector, and a gap between both electrode layers. An intervening electrolyte layer. Among such lithium batteries, a lithium secondary battery that can be repeatedly charged and discharged (hereinafter simply referred to as a lithium battery) has attracted attention as a main power source for portable communication terminals and portable electronic devices.

  In recent years, as this lithium battery, an all-solid-state battery that does not use an organic electrolyte for lithium conduction between the positive and negative electrodes has been proposed (see, for example, Patent Document 1). All solid-state batteries use a solid electrolyte (SE) as an electrolyte, and there are inconveniences associated with using an organic electrolyte, such as safety problems due to leakage of the electrolyte, and the boiling point of the organic electrolyte at high temperatures. The problem of heat resistance due to volatilization exceeding, the problem that the ionic conductivity of the organic electrolytic solution is greatly reduced at a low temperature and the battery reaction is lowered, or the electrolytic solution is frozen can be solved.

  Here, in Patent Document 1, as the battery is charged and discharged, the SE layer and the electrode layers (positive electrode layer and negative electrode layer) adjacent to the SE layer are easily peeled off. As a configuration to be solved, it is disclosed that a region layer that is a compound of one element of an electrode constituent material and one element of an SE layer constituent material is formed between the SE layer and the electrode layer.

JP 2004-281316 A

  However, as a result of various studies by the present inventors, in a lithium battery repeatedly charged and discharged, not only the electrode peels from the SE layer but also the positive electrode layer peels off from the positive electrode current collector. It became clear that it was the cause of short circuit between the positive and negative electrodes.

  The present inventors further examined the cause of the separation of the positive electrode layer from the positive electrode current collector. As a result, the positive electrode layer was removed due to changes in the temperature of the battery accompanying charging / discharging of the battery, insertion / extraction of lithium into the positive electrode layer, etc. The knowledge that it is for expansion and contraction was obtained. In particular, all battery components are solid, and in all solid-state lithium batteries formed by joining these components, in addition to the stress of expansion and contraction of the positive electrode layer, this occurs due to the expansion and contraction of the negative electrode layer and SE layer. The stress that acts on the positive electrode layer may promote peeling of the positive electrode layer from the current collector. Therefore, although it is considered necessary to examine the adhesion between the positive electrode layer and the positive electrode current collector, in the all-solid-state lithium battery including Patent Document 1, the adhesion between the positive electrode current collector and the positive electrode layer is considered. The current situation has not been studied at all.

  Accordingly, one of the objects of the present invention is to provide a lithium battery in which the positive electrode layer is hardly peeled off from the positive electrode current collector as the battery is charged and discharged.

  The present invention achieves the above-mentioned object by forming an intervening layer that adheres both between the positive electrode current collector and the positive electrode layer.

  The lithium battery of the present invention is roughly divided into two configurations. In any configuration, an intervening layer is provided between the positive electrode current collector and the positive electrode layer. However, the composition of the intervening layer differs depending on whether the positive electrode active material of the positive electrode layer is composed of an oxide or a sulfide.

  The lithium battery according to the first configuration of the present invention mediates lithium ion conduction between the positive electrode layer formed on the positive electrode current collector, the negative electrode layer paired with the positive electrode layer, and both layers. A lithium battery having a solid electrolyte layer. In this battery, the positive electrode active material contained in the positive electrode layer is an oxide, and the intervening layer comprising an oxide of a metal element contained in the positive electrode current collector is disposed between the positive electrode layer and the positive electrode current collector. It is characterized by having.

  The lithium battery according to the second configuration of the present invention mediates lithium ion conduction between the positive electrode layer formed on the positive electrode current collector, the negative electrode layer paired with the positive electrode layer, and both layers. A lithium battery having a solid electrolyte layer. In this battery, the positive electrode active material contained in the positive electrode layer is a sulfide, and an intervening layer made of a sulfide of a metal element contained in the positive electrode current collector is disposed between the positive electrode layer and the positive electrode current collector. It is characterized by having.

  According to the configuration of the present invention, the intervening layer exhibits high adhesion to both the positive electrode current collector and the positive electrode layer. As a result, a lithium battery in which the positive electrode layer is difficult to peel from the positive electrode current collector can be obtained.

As an embodiment of the lithium battery of the present invention, the interposition layer preferably has an electronic conductivity of 10 ⁻² S / cm or more.

  Since it is necessary to ensure electrical continuity between the positive electrode current collector and the positive electrode layer, the intervening layer needs to have electronic conductivity. If it is the interposition layer which has the electronic conductivity of the said structure, peeling of a positive electrode layer can be suppressed, without impairing the performance of a lithium battery.

  As one form of the lithium battery of the present invention, the metal element contained in the positive electrode current collector is copper (Cu), tin (Sn), chromium (Cr), nickel (Ni), iron (Fe), manganese (Mn) And at least one of vanadium (V).

  These metal elements are suitable as constituent elements of the current collector, and it is easy to form oxides and sulfides. Therefore, according to this configuration, it is possible to easily form an intervening layer that is in close contact with both the positive electrode current collector and the positive electrode layer.

  As one form of the lithium battery of the present invention, the intervening layer is preferably in close contact with the side surface of the positive electrode layer provided on the intervening layer.

  According to this configuration, since the intervening layer is in close contact with the bottom surface and the side surface of the positive electrode layer, it is possible to more effectively suppress the positive electrode layer from peeling off as the battery is charged / discharged.

  According to the lithium battery of the present invention, since the intervening layer exhibits high adhesion to the positive electrode current collector and the positive electrode layer, the positive electrode layer is difficult to peel from the positive electrode current collector. Can do. As a result, it can be set as the lithium battery which battery performance does not deteriorate easily with charging / discharging of a battery.

  The lithium battery of the present invention includes a positive electrode current collector, a positive electrode layer, a solid electrolyte layer (SE layer), a negative electrode layer, a negative electrode current collector, and a positive electrode current collector and a positive electrode layer. An intervening layer is provided between the two. The arrangement of each layer can be roughly divided into two configurations. The first configuration is a laminated structure in which the positive electrode layer and the negative electrode layer overlap each other when the battery is viewed in plan. A typical example of this battery is a button type battery in which a positive electrode layer and a negative electrode layer having approximately the same size are overlapped, and the area of the battery when viewed in plan can be reduced. The second configuration is a non-stacked structure in which the positive electrode layer and the negative electrode layer do not overlap when the battery is viewed in plan. In the case of this battery, even if a pinhole occurs in the thickness direction of the SE layer, it is easy to suppress a short circuit between both electrode layers. As a configuration of such an electrode, it is possible to form the positive electrode layer and the negative electrode layer in a comb-teeth shape and arrange them in parallel so as to be fitted to each other.

  Hereinafter, embodiments of the present invention will be described using a lithium battery having a laminated structure as an example.

<First embodiment>
≪Overall configuration of lithium secondary battery≫
The lithium battery in the present embodiment is a lithium battery 1 having a structure in which the positive electrode layer 13 and the negative electrode layer 15 have the same area when the battery is viewed in plan, and the two layers are exactly overlapped, that is, a so-called completely laminated structure (see FIG. 1). Specifically explaining the structure of the lithium battery 1 of the present embodiment, a structure in which an intervening layer 12, a positive electrode layer 13, an SE layer 14, and a negative electrode layer 15 are stacked in this order on a positive electrode current collector 11 having a current collecting function. have. Hereinafter, each component will be described in detail. In the lithium battery 1 of the present embodiment, the negative electrode layer 15 also serves as the negative electrode current collector. However, a negative electrode current collector may be separately provided on the negative electrode.

≪Each component≫
[Positive electrode current collector]
As the positive electrode current collector, a metal selected from Cu, Sn, Cr, Ni, Fe, Mn and V, or an alloy thereof is suitable. The positive electrode current collector may be formed as a metal film on an insulator, for example. The thickness of the positive electrode current collector is preferably 3 μm to 100 μm, and particularly preferably 5 μm to 25 μm. The current collector made of the metal film can be formed by a PVD method (physical vapor deposition method) or a CVD method (chemical vapor deposition method). In particular, when a metal film (current collector) is formed in a predetermined pattern, a current collector having a predetermined pattern can be easily formed on the insulator by using an appropriate mask.

[Positive electrode layer]
The positive electrode layer includes a positive electrode active material that occludes and releases lithium ions. As the positive electrode active material, from the group consisting of oxides, for example, lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), and olivine type lithium iron phosphate (LiFePO ₄ ) One selected or a mixture thereof can be preferably used. In addition, the positive electrode active material is one selected from the group consisting of sulfides such as sulfur (S), lithium sulfide (Li ₂ S), iron sulfide (FeS, FeS ₂ ) and titanium sulfide (TiS ₂ ), or these It may be a mixture of The thickness of the positive electrode layer is preferably 5 μm to 150 μm, and more preferably 10 μm to 100 μm. Moreover, it is preferable that the positive electrode layer further contains a conductive additive. Carbon black or graphite can be used as the conductive assistant.

  As a method for forming the positive electrode layer described above, a dry method (typically, a vapor deposition method such as a sputtering method or an electron beam evaporation method) or a wet method (typically a screen printing method or a coating method) is used. can do. Here, the positive electrode layer may be formed thicker than a negative electrode layer to be described later in order to realize a higher capacity of the lithium battery. Therefore, it is preferable to use a wet method such as a coating method as a method of forming the positive electrode layer. Since the coating method can form a relatively thick positive electrode layer in a short time, the productivity of the positive electrode layer can be improved.

  Moreover, when using a wet method, it is preferable to contain a binder in the slurry containing the active material and prevent the slurry from dripping when the slurry is applied onto the positive electrode current collector. The binder remains in the positive electrode layer even after the applied slurry is hardened and the positive electrode layer is formed. Therefore, it is preferable to use a binder having good electron conductivity as the binder. By doing in this way, the electrical resistance of a positive electrode layer, ie, the internal resistance of a lithium battery, falls, and the battery characteristic when it is set as a battery improves. As such a binder, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), or the like can be used.

[Intervening layer]
The lithium battery of the present invention includes an intervening layer that improves the adhesion between the positive electrode current collector and the positive electrode layer described above. The composition of the intervening layer is different depending on the composition of the positive electrode layer and the positive electrode current collector. Specifically, when the active material of the positive electrode layer is made of an oxide, the intervening layer is composed of an oxide of a metal element contained in the positive electrode current collector. Moreover, when the active material of a positive electrode layer consists of sulfides, an intervening layer is comprised from the sulfide of the metal element contained in a positive electrode electrical power collector. For example, when the positive electrode current collector is made of Cu and the positive electrode active material is an oxide, the intervening layer is made of Cu ₂ O or the like. When the positive electrode current collector is made of Cu and the positive electrode active material is a sulfide, the intervening layer is made of Cu ₂ S or the like.

  By limiting the composition of the intervening layer as described above, an intervening layer having high adhesion to both the positive electrode current collector and the positive electrode layer can be obtained. That is, since the positive electrode layer can be made difficult to peel from the positive electrode current collector, even if the positive electrode layer expands and contracts due to charging / discharging of the battery, there is almost no possibility that the positive electrode layer peels off.

Further, the intervening layer needs to have electronic conductivity in order to ensure conduction between the positive electrode current collector and the positive electrode layer, and it is preferable to ensure an electron conductivity of 10 ⁻² S / cm or more. Furthermore, the thickness of the intervening layer is preferably 5 nm to 100 nm, and more preferably 5 nm to 25 nm. When the intervening layer thickness is less than 5 nm, the effect of suppressing peeling of the positive electrode layer is reduced. On the other hand, if the thickness of the intervening layer exceeds 100 nm, the intervening layer has an electron conductivity smaller than that of the metal constituting the current collector, so that the intervening layer becomes a high resistance layer, which is not preferable. The intervening layer can be formed by a vapor phase method or the like.

[Negative electrode current collector]
As the negative electrode current collector, one selected from Cu, Ni, Fe, Cr, and alloys thereof can be suitably used. Since these metals do not form an intermetallic compound with lithium (Li), the bondability with the negative electrode layer, which will be described later, decreases due to problems caused by the intermetallic compound with lithium, specifically, expansion / contraction due to charge / discharge. Thus, it is possible to prevent a problem that the negative electrode layer easily falls off the negative electrode current collector. The thickness of the negative electrode current collector is preferably 3 μm to 100 μm, and more preferably 5 μm to 25 μm. Note that the negative electrode current collector (metal film) can also be formed by a PVD method or a CVD method, as in the case of the positive electrode.

[Negative electrode layer]
The negative electrode layer is composed of a layer containing a negative electrode active material that occludes and releases lithium ions. For example, as the negative electrode layer, one selected from the group consisting of Li metal and a metal capable of forming an alloy with Li metal, or a mixture or alloy thereof can be preferably used. The metal capable of forming an alloy with Li is at least one selected from the group consisting of aluminum (Al), silicon (Si), tin (Sn), bismuth (Bi), and indium (In) (hereinafter, referred to as “metal”). Alloyed material). Specific examples of the negative electrode layer include Li—Al, Li—Mn—Al, Si, Si—N, Si—Co, Si—Fe, and the like. The thickness of the negative electrode layer is preferably 1 μm to 100 μm, and more preferably 1 μm to 20 μm. In addition, the negative electrode layer may contain the conductive support agent similarly to the positive electrode layer, and may contain the binder if the negative electrode layer is produced by a coating method.

  A negative electrode layer containing such an element is preferable because the negative electrode layer itself can have a function as a current collector and has a high ability to occlude and release lithium ions. In particular, silicon (Si) has a higher ability to occlude and release lithium than graphite, and can increase the energy density of the battery.

  In addition, the use of an alloy phase with Li metal as the negative electrode layer has the effect of reducing the migration resistance of Li ions at the interface between the alloying material alloyed with Li metal and the Li ion conductive solid electrolyte layer. In addition, the increase in resistance of the alloying material in the initial charge of the first cycle is alleviated.

  Furthermore, when the single metal of the alloying material is used as the negative electrode layer, there is a problem that the discharge capacity becomes significantly smaller than the charge capacity in the first charge / discharge cycle. By using the negative electrode layer material obtained by alloying the material, this irreversible capacity is almost eliminated. This eliminates the need to fill the positive electrode active material amount by an irreversible capacity, thereby improving the capacity density of the lithium battery.

  The above-described method for forming the negative electrode layer is preferably a vapor deposition method. In addition, the negative electrode layer may be formed by pressing or an electrochemical method, or may be formed using a coating method.

[Solid electrolyte layer]
The solid electrolyte layer (SE layer) is a layer that mediates lithium ion conduction between the positive electrode and the negative electrode. The properties required for the SE layer are high lithium ion conductivity and low conductivity. Specifically, it is preferable that the lithium ion conductivity is 10 ⁻⁴ S / cm or more and the conductivity is 10 ⁻⁸ S / cm or less.

  As the SE layer, those containing lithium (Li), phosphorus (P), sulfur (S), and further containing oxygen (O) can be used. In addition, a La—Li—Ti composite oxide may be used as the SE layer. Further, the SE layer may have a structure of two or more layers having different compositions on the positive electrode layer side and the negative electrode layer side, and the interface resistance between each electrode and the solid electrolyte layer can be lowered. For example, an amorphous film or a polycrystalline film made of Li—P—S—N or Li—P—O—N is formed on the positive electrode layer, and an amorphous film or a polycrystalline film made of Li—P—S—O or the like is formed on the negative electrode layer. The thickness of the SE layer is preferably 3 μm to 100 μm in total for both single and multiple layers, and more preferably 5 μm to 25 μm.

  Note that the SE layer may be impregnated with an ionic liquid. A lithium ion conductive ionic liquid is an ionic liquid composed of a combination of an organic cation and an anion. Here, the ionic liquid impregnated in the solid electrolyte layer may or may not contain a lithium-containing salt. By impregnating the solid electrolyte with the ionic liquid, the lithium ion conductivity of the solid electrolyte layer can be increased.

  According to the lithium battery having the above configuration, the intervening layer can suppress separation of the positive electrode layer from the positive electrode current collector.

  Hereinafter, lithium batteries (Examples 1 to 3) having the configurations described in the embodiments are manufactured, and lithium batteries (Comparative Examples 1 to 3) having no intervening layer are manufactured as a comparison of Examples. The cycle characteristics of were investigated.

<Example 1>
First, a 15 μm thick Cu foil was prepared as a positive electrode current collector, and an intervening layer made of Cu ₂ O was formed on the Cu foil by an electron beam evaporation method. The intervening layer thickness was 50 nm.

Next, a positive electrode layer using LiMn ₂ O ₄ as a positive electrode active material was formed on the intervening layer by an electron beam evaporation method using LiMn ₂ O ₄ as a raw material. The positive electrode layer thickness was 3 μm.

Further, an SE layer was formed on the positive electrode layer by a binary resistance heating vapor deposition method using P ₂ S ₅ powder and Li ₂ S powder as raw materials. The molar ratio of P ₂ S ₅ to Li ₂ S in the SE layer was P ₂ S ₅ / Li ₂ S = 7/3, and the SE layer thickness was 3 μm.

  Finally, a negative electrode layer made of a Li metal film was formed on the SE layer by resistance heating vapor deposition. The negative electrode layer thickness was 5 μm.

<Example 2>
In Example 2, a lithium battery using FeS ₂ as a positive electrode active material was produced. The intervening layer was composed of a compound corresponding to the sulfide positive electrode active material. Specifically, since the positive electrode current collector was Cu and the positive electrode active material was sulfide, the intervening layer was Cu ₂ S. The layers other than the positive electrode layer and the intervening layer are the same as those in Example 1. In addition, the thickness of each layer including the positive electrode current collector and the positive electrode layer is the same as that of Example 1.

<Example 3>
In Example 3, a lithium battery was fabricated using LiMn ₂ O ₄ as the positive electrode active material and stainless steel foil (SUS304) as the positive electrode current collector. Further, an intervening layer was composed of this oxide positive electrode active material and a compound corresponding to the current collector of SUS304. Specifically, since the positive electrode current collector is SUS304 containing Ni and the positive electrode active material is an oxide, the intervening layer is NiO. The layers other than the positive electrode current collector, the positive electrode layer, and the intervening layer are the same as those in Example 1. In addition, the thickness of each layer including the positive electrode current collector, the positive electrode layer, and the intervening layer is the same as in Example 1.

<Comparative Examples 1-3>
In Comparative Examples 1 to 3, conventional lithium batteries having no intervening layer were produced. Comparative Example 1 is the same as the battery of Example 1 except that no intervening layer is provided. Comparative Examples 2 and 3 are the same as the batteries of Examples 2 and 3 except that no intervening layer is provided.

<Test example>
In the lithium batteries of Examples 1 to 3 and Comparative Examples 1 to 3 described above, a test was conducted to determine whether the batteries can withstand repeated charge and discharge. In addition, the test was implemented by charging / discharging a battery with the following current density and capacity density.
Battery of Example 1 and Comparative Example 1 Current density 0.1 mA / cm ² , Capacity density 0.2 mAh / cm ²
Battery of Example 2 and Comparative Example 2 Current density 0.1 mA / cm ² , Capacity density 0.5 mAh / cm ²
Battery of Example 3 and Comparative Example 3 Current density 0.1 mA / cm ² , capacity density 0.2 mAh / cm ²
The test results of this cycle characteristic are shown in Table 1 in the next stage.

  As is clear from the results in Table 1, the lithium batteries of Examples 1 to 3 were able to be charged / discharged for 200 cycles, and could be charged / discharged thereafter. On the other hand, the battery of Comparative Example 1 caused a short circuit after only 5 cycles, and the battery of Comparative Example 3 caused a short circuit after 8 cycles. Further, the battery of Comparative Example 2 became incapable of charge / discharge because the internal resistance of the battery became too high after 12 cycles. When the batteries of Comparative Examples were disassembled and examined, in the batteries of Comparative Examples 1 and 3, the SE layer was peeled off together with the positive electrode layer, and the surface of the negative electrode layer facing the positive electrode layer was covered with the SE layer. There was a part that was not known. Therefore, it is estimated that the exposed negative electrode layer and the positive electrode layer are short-circuited. On the other hand, in the battery of Comparative Example 2, there is a portion where the positive electrode layer is separated from the positive electrode current collector and floated, and it is presumed that the internal resistance has increased due to this.

<Second embodiment>
In the second embodiment, a lithium battery having a different intervening layer structure from the first embodiment will be described. FIG. 2 is a cross-sectional view showing the lithium battery 2 of the second embodiment. In addition, since the composition and formation method of each layer of this embodiment are the same as 1st embodiment, only the difference of a structure is demonstrated.

  The lithium battery 2 of the present embodiment is the same as the first embodiment in that the intervening layer 22, the positive electrode layer 23, the SE layer 24, and the negative electrode layer 25 are formed on the positive electrode current collector 21 in this order. Here, the intervening layer 22 is formed so as to cover the entire top surface of the positive electrode current collector 21 and also covers the side surface of the positive electrode layer 23.

  In order to form such an intervening layer 22, first, a mask is formed on the positive electrode current collector 21, and the intervening layer 22 having the same area as the positive electrode layer 23 to be formed in a later step is formed. Next, the positive electrode layer 23 is formed on the formed intervening layer 22. Then, the upper surface of the positive electrode layer 23 is masked, and the intervening layer 22 is formed so as to cover the side surface of the positive electrode layer 23 by a vapor deposition method.

  According to the configuration of the present embodiment, since the positive electrode layer 23 is supported by the intervening layer 22 also on its side surface, it is possible to obtain a battery in which the positive electrode layer 23 is more difficult to peel off than the battery of the first embodiment.

  In addition, the lithium battery of this invention is not limited to embodiment mentioned above, It can change suitably, without deviating from the summary of this invention. Specifically, the arrangement of each layer constituting the lithium battery may be other than the above-described embodiment, for example, a non-laminated structure, but any positive electrode can be selected. An intervening layer may be formed between the current collector and the positive electrode layer so that they are not in direct contact with each other.

  The lithium battery of the present invention can be suitably used as a power source for portable devices and the like.

It is a longitudinal cross-sectional view of the lithium battery as described in 1st embodiment. It is a longitudinal cross-sectional view of the lithium battery as described in 2nd embodiment.

Explanation of symbols

1,2 Lithium battery
11,21 Cathode current collector 12,22 Intervening layer 13,23 Cathode layer
14,24 Solid electrolyte layer (SE layer) 15,25 Negative electrode layer

Claims (5)

A lithium battery having a positive electrode layer formed on a positive electrode current collector, a negative electrode layer paired with the positive electrode layer, and a solid electrolyte layer that mediates lithium ion conduction between the two layers,
The positive electrode active material contained in the positive electrode layer is an oxide,
A lithium battery comprising an intervening layer made of an oxide of a metal element contained in a positive electrode current collector between the positive electrode layer and the positive electrode current collector. A lithium battery having a positive electrode layer formed on a positive electrode current collector, a negative electrode layer paired with the positive electrode layer, and a solid electrolyte layer that mediates lithium ion conduction between the two layers,
The positive electrode active material contained in the positive electrode layer is a sulfide,
A lithium battery comprising an intervening layer made of a sulfide of a metal element contained in a positive electrode current collector between the positive electrode layer and the positive electrode current collector. The lithium battery according to claim 1, wherein the intervening layer has an electronic conductivity of 10 ⁻² S / cm or more.   4. The lithium according to claim 1, wherein the metal element contained in the positive electrode current collector is at least one of Cu, Sn, Cr, Ni, Fe, Mn, and V. 5. battery.   The lithium battery according to claim 1, wherein the intervening layer is also in close contact with a side surface of a positive electrode layer provided on the intervening layer.

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