JP4811613B2 - Non-aqueous electrolyte secondary battery electrode plate, non-aqueous electrolyte secondary battery electrode plate manufacturing method, and non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to an electrode plate used for a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, a method for producing the electrode plate, and a non-aqueous electrolyte secondary battery.

  A non-aqueous electrolyte secondary battery represented by a lithium ion secondary battery has a high energy density and a high voltage, and has a memory effect during charging / discharging (when the battery is charged before it is completely discharged, Since there is no phenomenon in which the capacity decreases, it is used in various fields such as portable devices and large devices. In recent years, the use of secondary batteries has attracted attention in fields where high output characteristics are required, such as electric vehicles, hybrid vehicles, and power tools.

  The non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a separator, and an organic electrolyte. And as said positive electrode and negative electrode, what is equipped with the electrode active material layer formed by apply | coating an electrode active material layer forming solution on collector surfaces, such as metal foil, is generally used.

  The electrode active material layer forming solution includes a dischargeable active material, a binder, and a conductive material (however, when the active material also exhibits a conductive effect, the conductive material may be omitted), or If necessary, other materials are used and kneaded and / or dispersed in an organic solvent to prepare a slurry. A method of manufacturing an electrode plate having an electrode active material layer by applying an electrode active material layer forming solution to the surface of the current collector and then drying to form a coating film on the current collector and pressing (For example, paragraphs [0019] to [0026] in Patent Document 1; Patent Document 2 [Claim 1], paragraphs [0051] to [0055]).

  At this time, the active material contained in the electrode active material layer forming solution is a particulate compound dispersed in the solution, and is not easily fixed to the current collector surface only by being applied to the current collector surface. Even if an electrode active material layer forming solution that does not contain a binder is applied to a current collector and dried to form a coating film, the coating film is easily peeled off from the current collector. That is, the electrode active material is bound through the binder and is fixed to the surface of the current collector to form an electrode active material layer. Therefore, the binder was essentially an essential component.

  Moreover, the said electrically conductive material is used in order to ensure favorable electronic conductivity of each active material and collector in an electrode active material layer, and to reduce the volume resistivity of electrode active material layer itself.

JP 2006-310010 A JP 2006-107750 A

  As described above, in recent years, development of large-capacity secondary batteries has been promoted particularly in fields that require high output characteristics such as electric vehicles, hybrid vehicles, and power tools. Even for secondary batteries used in relatively small devices of mobile phones, the devices tend to be multifunctional, so high output characteristics and high-speed charge / discharge characteristics are expected as well as capacity. Yes. On the other hand, in order to realize high output and high speed charge / discharge in the secondary battery, it is necessary to lower the impedance of the battery. This is because a battery with high impedance has a problem that its capacity cannot be fully utilized during high output discharge and high speed charge.

  In order to reduce the impedance of the secondary battery, it is effective to reduce the impedance of the electrode plate. To date, a method of increasing the electrode area by thinning the electrode active material layer formed on the electrode plate is known. ing. In addition, since non-aqueous electrolytes used for lithium ion secondary batteries generally have higher resistance than aqueous electrolytes, they are thin and wide-area electrodes compared to other batteries such as lead-acid batteries from the beginning of development. A form has been developed in which the distance between the positive electrode and the negative electrode is shortened.

However, considering the presence of components other than the active material in the electrode active material layer, there is a limit in reducing the thickness of the layer, and the lower limit of the thickness of the electrode active material layer is substantially up to several tens of μm. It was.

  The present inventors paid attention to the presence of a binder in the electrode active material layer as one of the factors that make it difficult to reduce the thickness of the electrode active material layer. As described above, the binder has been used as an essential component of the electrode active material layer until now. However, the presence of the binder increases the volume of the electrode active material layer, so that the electrode active material layer physically As a result, the thickness increased. Furthermore, the present inventors have the problem that the movement distance of ions and electrons becomes longer due to the presence of the binder between the active materials, and the permeability of the electrolytic solution in the electrode active material layer is reduced, And it discovered that there was a problem that the contact area of this electrolyte solution and an active material will become small. And it was inferred that the binding material causing these problems is one of the negative factors for increasing the output of the electrode plate.

  The present invention has been accomplished in view of the above circumstances, and is an electrode plate for a non-aqueous electrolyte secondary battery capable of high-power charge / discharge, comprising an electrode active material layer configured without depending on the presence of a binder. In addition, the present invention provides a method for producing a current collector having an electrode active material layer that adheres well to the surface of the current collector and is difficult to peel without using a binder. An object of the present invention is to provide a nonaqueous electrolyte secondary battery capable of output charge / discharge.

  The inventors of the present invention, regardless of the presence of the binder, have an electrode active material comprising at least two layers of a dense layer and a void-forming layer, wherein the active material is bonded to the current collector surface by bonding to each other. It has been found that an electrode plate for a non-aqueous electrolyte secondary battery capable of further thinning and capable of exhibiting a very high output can be realized if it is a material layer. The present invention, which is an electrode plate for use and a nonaqueous electrolyte secondary battery using the same, was completed.

In addition, as a means for fixing the active material to the current collector surface by bonding the active materials without using a binder, the present inventors have dissolved a lithium salt and an appropriate metal salt. By applying a solution to the current collector surface and heating at a high temperature, the lithium transition metal composite oxide is produced on the current collector surface. The inventors have found that it is possible to form a coating film that is at least partially bonded and fixed to the surface of the current collector and is difficult to peel off, and the invention of a method for producing an electrode plate for a non-aqueous electrolyte secondary battery has been completed.

That is, the present invention
(1) An electrode plate for a non-aqueous electrolyte secondary battery comprising an electrode active material layer composed of an active material on at least a part of the surface of a current collector, wherein the electrode active material layer comprises the current collector It comprises at least two layers of a dense layer and a void-forming layer from the body side, and the dense layer is directly on the current collector and the void-forming layer,
The dense layer is a layer formed by a layer structure in which the active materials are continuously present by bonding the active materials to each other, and substantially free of voids, The void-forming layer is formed of a layer structure in which the active materials are continuously present by partially joining the active materials, and the porous layer has voids through which the electrolytic solution can permeate. The active material constituting the dense layer and the void forming layer is a lithium transition metal composite oxide, and the transition metal contained in the lithium transition metal composite oxide that is the active material constituting the dense layer; active material and the transition metal contained in the lithium-transition metal composite oxide as an active material for constituting the gap forming layer Ri allogeneic der in arithmetic mean of the measured values in the electron microscope observation, constituting the gap forming layer The average minimum grain size is less than or 10 nm 100 nm, and an average maximum particle diameter and wherein 900nm less der Rukoto than 150nm non-aqueous electrolyte secondary battery electrode plate,
(2) The electrode plate for a non-aqueous electrolyte secondary battery according to (1) above, wherein the electrode active material layer has a thickness of 300 nm to 10 μm.
(3) The above (1) or (1), wherein the discharge capacity retention rate is 50% or more at a discharge rate of 50C or more, assuming that the discharge capacity retention rate when discharging at a discharge rate of 1C is 100% (2) The electrode plate for a nonaqueous electrolyte secondary battery according to any one of
(4) The electrode plate for a non-aqueous electrolyte secondary battery according to any one of (1) to ( 3) , wherein the electrode active material layer contains a conductive material,
(5) The electrode plate for a non-aqueous electrolyte secondary battery according to any one of (1) to ( 4) , wherein the electrode active material layer has a thickness of 1 μm or more,
(6) The non-aqueous electrolyte according to any one of (1), (3), (4), or (5 ) above, wherein the electrode active material layer has a thickness of 10 μm or more. Secondary battery electrode plate,
(7) The electrode plate for a non-aqueous electrolyte secondary battery according to any one of (1) to ( 6) , wherein the active material is lithium titanate,
(8) A negative electrode plate for a non-aqueous electrolyte secondary battery comprising an electrode active material layer composed of an active material on at least a part of the surface of the current collector, wherein the electrode active material layer comprises the current collector It comprises at least two layers from the body side: a dense layer and a void-forming layer, the dense layer is directly connected to the current collector and the void-forming layer, and the dense layer has the active material bonded to each other Thus, the active material is a layer formed by a layer structure in which the active material is continuously present, and is substantially configured without voids. The porous layer is formed by a layer structure in which the active material is continuously present and has voids through which the electrolytic solution can permeate, and the dense layer and the void forming layer. The active material composing lithium transition metal composite oxidation The transition metal contained in the lithium transition metal composite oxide that is the active material constituting the dense layer is the same as the transition metal contained in the lithium transition metal composite oxide that is the active material constituting the void forming layer. A negative electrode plate for a nonaqueous electrolyte secondary battery,
(9) preparing an electrode active material layer forming solution in which at least one of the lithium element containing compound and one or more of the metal element containing compounds including the transition metal is dissolved, and collecting the electrode active material layer forming solution A coating film is formed by applying to at least a part of the body surface, and then a heat source is not provided on both sides of the current collector or the current collector film on the current collector on which the coating film is formed. A non-aqueous electrolyte characterized in that an electrode active material layer is formed by forming a lithium transition metal composite oxide on a current collector surface by being installed on the surface side and heated at a temperature of 150 ° C. or higher Manufacturing method of electrode plate for secondary battery,
(10) The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to ( 9) , wherein the electrode active material layer forming solution contains a conductive material,
(11) The method for producing an electrode plate for a nonaqueous electrolyte secondary battery according to ( 9) or (10) above, wherein an electrode active material layer having a thickness of 1 μm or more is formed,
(12) The method for producing an electrode plate for a nonaqueous electrolyte secondary battery according to ( 11) above, wherein an electrode active material layer having a thickness of 10 μm or more is formed,
(13) A nonaqueous electrolyte secondary battery comprising a positive electrode plate, a negative electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolyte containing a nonaqueous solvent, At least one of the positive electrode plate and the negative electrode plate is the electrode plate for a non-aqueous electrolyte secondary battery according to any one of the above (1) to (7). Secondary battery,
(14) A non-aqueous electrolyte secondary battery comprising a positive electrode plate, a negative electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolyte containing a non-aqueous solvent, A non-aqueous electrolyte secondary battery, wherein the negative electrode plate is a negative electrode plate for a non-aqueous electrolyte secondary battery according to (8) above,
Is a summary.
Moreover, the negative electrode plate for nonaqueous electrolyte secondary batteries as described in said (8) contains the following aspects.
(15) The negative electrode plate for a non-aqueous electrolyte secondary battery according to (8), wherein the electrode active material layer has a thickness of 300 nm to 10 μm,
(16) The above (8) or (8), wherein the discharge capacity retention rate is 50% or more at a discharge rate of 50C or more, assuming that the discharge capacity retention rate when discharging at a discharge rate of 1C is 100% (15) The negative electrode plate for a non-aqueous electrolyte secondary battery according to any one of
(17) The non-aqueous electrolyte secondary battery according to any one of (8), (15), or (16) above, wherein the electrode active material layer contains a conductive material. Negative electrode plate,
(18) The non-aqueous electrolyte 2 according to any one of (8), (15), (16), or (17) above, wherein the thickness of the electrode active material layer is 1 μm or more. Negative plate for secondary battery,
(19) The electrode active material layer has a thickness of 10 μm or more, and the non-conductivity according to any one of (8), (15), (16), (17) or (18) Negative electrode plate for water electrolyte secondary battery,
(20) The non-active material according to any one of (8), (15), (16), (17), (18) or (19), wherein the active material is lithium titanate Negative electrode plate for water electrolyte secondary battery.

  The electrode plate for a non-aqueous electrolyte secondary battery of the present invention can exhibit very high output characteristics. At least one of the factors enabling the high output of the electrode plate for a non-aqueous electrolyte secondary battery solution of the present invention is that the electrode active material layer on the electrode plate is a current collector regardless of the presence of a binder. This is probably because the moving distance of ions and electrons is shortened compared to the conventional electrode active material layer because the active material is fixed to the surface by bonding to each other.

  In the present invention, since the electrode active material layer does not substantially contain a binder, the electrode active material layer can be thinned to about 300 nm to 10 μm. Moreover, since there is no binder in the electrode active material layer in the present invention, the unit weight of the active material is relatively increased compared to the conventional electrode active material layer in which the binder is used. Even when the thickness is reduced, it is possible to maintain a good electric capacity.

  Furthermore, the electrode active material layer in the present invention exhibits the following effects by including at least two layers of a dense layer and a void forming layer from the current collector side. That is, the electrolyte solution penetrates well in the void forming layer, and ions can move smoothly. Also, due to the presence of the dense layer between the gap forming layer and the current collector, electrons are highly desirable to conduct between the current collector and the active material. Therefore, in the electrode plate for a non-aqueous electrolyte secondary battery of the present invention, the behavior of both ions and electrons is very smooth, and as a result, it seems that high output charge / discharge is possible.

  Therefore, the electrode active material layer in the present invention can be constituted not including a conductive material as well as a binder. Even without a conductive material, good electrical conductivity is maintained, and the unit weight of the relative active material in the electrode active material layer is increased by the amount of conductive material removed, resulting in higher output charge / discharge. It is possible to provide an electrode for a non-aqueous electrolyte secondary battery excellent in the above.

  On the other hand, the electrode active material layer in the present invention can contain a conductive material in addition to the active material, and in this aspect of the present invention, the film thickness is substantially larger than that of the electrode active material layer consisting essentially of the active material. Although the thickness increases, the amount of the active material itself can be increased accordingly, which is excellent in that the capacity can be increased in addition to the increase in output.

Further, the production method of the present invention, which is a method for producing an electrode plate for a non-aqueous electrolyte secondary battery, disperses a particulate lithium transition metal composite oxide as an active material in advance in a coating solution as in the prior art. Unlike the method of applying a coating to the surface of the current collector, drying and crimping, a method of applying a coating solution containing a lithium salt and an appropriate metal salt to the surface of the current collector and heating is employed. . According to this method, the lithium transition metal composite oxide, which is an active material, is generated on the current collector surface. At this time, the active materials are at least partially joined to each other and fixed to the current collector. An electrode active material layer is formed without using a binder.

In addition, since the lithium transition metal composite oxide produced on the current collector surface is formed as very small particles by the production method of the present invention, the surface area per unit weight of the electrode active material layer can be increased. As a result, even if the film thickness is small, it is excellent in that a desirable electric capacity is secured.

And if it is a non-aqueous electrolyte secondary battery using the electrode plate for non-aqueous electrolyte secondary batteries of the said invention as at least one of a positive electrode plate and the said negative electrode plate, a very high output characteristic is shown. .

[Electrode plate for non-aqueous electrolyte secondary battery]
An electrode plate for a non-aqueous electrolyte secondary battery according to the present invention includes a current collector and an electrode active material layer formed by adhering the active material to the current collector surface by at least partial bonding. . Below, the best form of the electrode plate for nonaqueous electrolyte secondary batteries of this invention is demonstrated.

(Current collector)
The current collector used in the present invention is not particularly limited as long as it is generally used as a positive electrode current collector or a negative electrode current collector of a positive electrode plate for a nonaqueous electrolyte secondary battery. For example, a foil made of a simple substance such as an aluminum foil, a nickel foil, or a copper foil or an alloy, or a highly conductive foil such as a carbon sheet, a carbon plate, and a carbon textile is preferably used.

  The thickness of the current collector is not particularly limited as long as it is generally a thickness that can be used as a current collector for a positive electrode plate or a negative electrode plate for a nonaqueous electrolyte secondary battery, but is preferably 10 to 100 μm. More preferably, it is 50 μm.

(Electrode active material layer)
In order to explain the characteristics of the electrode active material layer in the present invention, FIG. 1 and FIG. 2 are shown. FIG. 1 shows a cross section of the electrode plate 1 for a non-aqueous electrolyte secondary battery of the present invention cut in a direction perpendicular to the surface of the current collector 2 when observed with an electron microscope at a magnification of 50,000 times. It is a photograph. As shown in FIG. 1, in the electrode plate 1 for a non-aqueous electrolyte secondary battery of the present invention, an electrode active material layer 5 made of an active material is formed on a current collector 2, and the electrode active material layer 5 Is composed of a dense layer 3 and a void forming layer 4 from the current collector 2 side. The dense layer 3 is formed by a layer structure in which the active materials are continuously present by bonding the active materials to each other, and is formed in a state substantially free of voids. On the other hand, the void-forming layer 4 is formed of a layer structure in which the active materials are continuously present by partially joining the active materials, and the void-forming layer 4 has a void having voids through which the electrolytic solution can permeate. It is formed as a layer. The dense layer 3 and the void forming layer 4 are formed from components having the same contents. That is, the active material constituting the dense layer 3 and the active material constituting the void forming layer 4 are active materials having the same composition. On the other hand, FIG. 2 is an electron micrograph obtained by observing the state of the top surface of the electrode plate 1 for a nonaqueous electrolyte secondary battery 1 as viewed from the gap forming layer 4 side at a magnification of 60000 times. As visually confirmed from FIG. 2, it is shown that a plurality of voids exist in the void forming layer.

In addition, regarding the dense layer 3, “substantially free of voids” means that the active materials are closely bonded to each other, so that no voids are observed with the naked eye when observed with an electron microscope at a magnification of 50,000 times. Means state. The thickness of the dense layer 3 is very small compared to the gap forming layer 4, but the presence of the dense layer 3 between the gap forming layer 4 and the current collector 1 makes it possible to collect the current collector 1 and the electrode active material layer. The exchange of electrons between 5 becomes very smooth, the conductivity is improved, and good conductivity is ensured even if no conductive material is contained, and as a result, a very high output performance is exhibited.

The electrode active material layer 5 in this invention is comprised from the dischargeable active material generally used in the electrode plate for nonaqueous electrolyte secondary batteries. Examples of the active material, for example _{LiCoO 2, LiMn 2 O 4,} LiNiO 2, LiFeO 2, LiTiO 2, LiFePO 4 and the like lithium transition metal composite oxide such.

  The electrode plate for a non-aqueous electrolyte secondary battery of the present invention can be used as either a positive electrode plate or a negative electrode plate of a non-aqueous electrolyte secondary battery, or both of the positive electrode plate and the negative electrode plate of the present invention. An electrode plate may be used. In particular, the use as a positive electrode plate is preferable because it can be used in combination with a conventional negative electrode because it has a wide range of applications in that many metal oxides can be applied. Moreover, the use as a negative electrode plate is preferable from the viewpoint that cycle characteristics are improved due to excellent adhesion. When used for both electrodes, high-speed charge / discharge is possible and cycle characteristics are improved.

Since the electrode active material layer in the present invention described above is formed by coating the active material together and fixing to the surface of the current collector without using a binder, compared with the thickness of the conventional electrode active material layer And can be formed very thin. More specifically, the electrode active material layer in the present invention can be formed to a thickness of 300 nm or more and 10 μm or less. However, the above description does not exclude the formation of the electrode active material layer in the present invention with a thickness exceeding 10 μm. Further, when it is desired to increase the capacity, the thickness of the electrode active material layer can be appropriately determined. In addition, when forming the electrode active material layer in this invention in thickness exceeding 10 micrometers, it is desirable to add a electrically conductive material to an electrode active material layer formation solution.

  The size of the particles of the active material constituting the electrode active material layer 5 in the present invention is not particularly limited, but is smaller than the particle size of a general active material constituting the conventional electrode active material layer, Further, the particle size of the active material constituting the dense layer 3 tends to be smaller than that of the active material constituting the void forming layer 4. In order to increase the output of the electrode plate, it is preferable that the particle size is small. From this point of view, the size of the active material constituting the void forming layer 4 can be determined by using an image analysis type particle size distribution measurement software ( It is preferable that the average minimum particle size is 10 nm or more and less than 100 nm, and the average maximum particle size is 200 nm or more and less than 900 nm. In addition, according to the manufacturing method of the electrode plate for nonaqueous electrolyte secondary batteries of this invention mentioned later, the space | gap formation layer 4 can be easily comprised with the very small particle size shown above.

Moreover, according to the small particle size which comprises the space | gap formation layer 4 as mentioned above, the surface area per weight unit of the said electrode active material layer can be increased compared with the past. Since the surface area is understood as a contact area between the active material and the electrolytic solution, it is preferable to increase the surface area because it means that higher output of the electrode plate is promoted.

(Other materials)
The electrode active material layer 5 can be composed of only the above-described active material, but may contain additional additives without departing from the spirit of the present invention. For example, as described above, good conductivity can be ensured without using a conductive material in the present invention, but this does not exclude the use of a conductive material in the present invention. The electrode active material layer 5 of the present invention may appropriately contain a conductive material. Even when a conductive material is added, the thickness of the electrode active material layer can be 10 μm or less. Moreover, you may form the thickness of the electrode active material layer 5 in thickness exceeding 10 micrometers by adding the electrically conductive material and also increasing the quantity of an active material.

  As said electrically conductive material, what is normally used for the electrode plate for nonaqueous electrolyte secondary batteries can be used, and carbon materials, such as carbon black, such as acetylene black and ketjen black, are illustrated. The average particle size of the conductive material is preferably about 20 nm to 50 nm. The average particle diameter is obtained by an arithmetic average obtained from actual measurement using an electron microscope, as in the method of measuring the particle diameter of the active material. When using a conductive material, it is necessary to keep in mind that the space | gap in the space | gap formation layer 4 is especially maintained to such an extent that electrolyte solution can osmose | permeate.

  As another optional additive, in order to further improve the adhesion between the current collector and the active material, a metal oxide that does not function as an active material may be included in the electrode active material layer 5. The metal oxide as the additive is not particularly limited, and examples thereof include cobalt oxide, nickel oxide, titanium oxide, zirconium oxide, tin oxide, and manganese oxide.

(Electrode output evaluation method)
The output performance of the electrode plate for a nonaqueous electrolyte secondary battery of the present invention can be evaluated by determining the discharge capacity retention rate (%). More specifically, the discharge rate 1C is set such that the theoretical value of the discharge capacity (mAh / g) of the active material is completed in 1 hour, and the discharge actually measured at the set discharge rate of 1C. The capacity (mAh / g) is set to a discharge capacity maintenance rate of 100%. The discharge capacity (mAh / g) when the discharge rate is further increased is measured, and the discharge capacity retention ratio (%) can be obtained from the following equation 1.

(Formula 1)

  In the present invention, it is desirable that a discharge capacity maintenance rate of 50% or more is exhibited at a discharge rate of 50C or more. More preferably, it is desirable that a discharge capacity maintenance rate of 50% or more is exhibited at a discharge rate of 100C or more. However, if the discharge rate is 2000 C or higher, a system that can withstand a large current is required, which is not desirable.

  From another point of view, it is desirable that the discharge capacity maintenance rate is high. When the discharge rate is 50 C, the discharge capacity maintenance rate is 50% or more, or 80% or more, and even 100%. It is desirable that the rate be indicated.

  In addition, the said discharge capacity is calculated | required by measuring the discharge capacity of electrode itself with a tripolar beaker cell.

[Method for producing electrode plate for non-aqueous electrolyte secondary battery]
Next, a method for producing the electrode plate for a non-aqueous electrolyte secondary battery of the present invention (hereinafter simply referred to as “the production method of the present invention”) will be described. In the production method of the present invention, an electrode active material layer forming solution is prepared by dissolving a compound serving as a precursor of an active material in a solvent, and this is applied to the surface of the current collector, and then heated to collect the current. An active material such as a lithium transition metal composite oxide is generated on the surface of the body to form an electrode active material layer, and an electrode plate for a non-aqueous electrolyte secondary battery is manufactured. At this time, the binder is not substantially added to the electrode active material forming solution, and when the active material is generated on the surface of the current collector, the active materials are bonded to each other and the surface of the current collector is formed. By utilizing the close contact, a coating film in which the active material is fixed on the surface of the current collector is formed. Below, the manufacturing method of this invention is demonstrated in detail.

(Active material precursor)
The electrode active material layer forming solution is prepared by using a metal element-containing compound containing a metal constituting the active material generated on the current collector surface as a precursor of the active material and dissolving it in a solvent. Can do. As the metal element-containing compound, a lithium element-containing compound and one or more metal element-containing compounds containing any metal element selected from cobalt, nickel, manganese, iron, or titanium are used.

  Examples of the metal element-containing compound include chlorides, nitrates, sulfates, perchlorates, acetates, phosphates and bromates of other metal elements such as lithium element and cobalt. Among them, in the present invention, chloride, nitrate, and acetate are preferably used because they are easily available as general-purpose products. In particular, nitrate is preferably used because it has good film forming properties for a wide variety of current collectors.

For example, as an active material precursor for finally generating LiCoO ₂ on the current collector, a compound made of Li and a compound made of Co can be used in combination as main raw materials, and further, if necessary Other raw materials can also be used in combination.
Examples of the compound comprising Li include lithium citrate tetrahydrate, lithium perchlorate trihydrate, lithium acetate dihydrate, lithium nitrate, and lithium phosphate, and from Co Examples of the compound include cobalt (II) chloride hexahydrate, cobalt (II) formate dihydrate, cobalt (III) acetylacetonate, cobalt (II) acetylacetonate dihydrate, cobalt acetate ( II) Tetrahydrate, cobalt (II) oxalate dihydrate, cobalt (II) nitrate hexahydrate, cobalt (II) ammonium chloride hexahydrate, sodium cobalt (III) nitrite, and cobalt sulfate (II) The heptahydrate etc. are mentioned.
The combination ratio (Li: Co = X: 1) of the compound composed of Li and the compound composed of Co used as the main raw material is not particularly limited, but is preferably 1 ≦ X <2, and preferably 1 ≦ X ≦ 1. 2 is more preferable.
When the combination ratio is out of the above range, a positive electrode plate having desired performance may not be efficiently manufactured.

Further, for example, as an active material precursor for finally generating LiNiO ₂ on the current collector and finally on the current collector, a compound composed of Li and a compound composed of Ni are combined as main raw materials. Further, other raw materials can be used in combination as required.
Examples of the compound composed of Li include lithium citrate tetrahydrate, lithium perchlorate trihydrate, lithium acetate dihydrate, lithium nitrate, and lithium phosphate, and also composed of Ni. Examples of the compound include nickel chloride (II) hexahydrate, nickel acetate (II) tetrahydrate, nickel perchlorate (II) hexahydrate, nickel bromide (II) trihydrate, nitric acid Examples include nickel (II) hexahydrate, nickel (II) acetylacetonate dihydrate, nickel (II) hypophosphite hexahydrate, and nickel (II) sulfate hexahydrate.
The combination ratio of the compound composed of Li and the compound composed of Ni used as the main raw material (Li: Ni = X: 1) is not particularly limited, but is preferably 1 ≦ X <2, and preferably 1 ≦ X ≦ 1. 2 is more preferable.
When the combination ratio is out of the above range, a positive electrode plate having desired performance may not be efficiently manufactured.

Further, for example, as an active material precursor for finally generating LiMn ₂ O ₄ on the current collector, a compound composed of Li and a compound composed of Mn can be used in combination as a main raw material, If necessary, other raw materials can be used in combination.
Examples of the compound composed of Li include lithium citrate tetrahydrate, lithium perchlorate trihydrate, lithium acetate dihydrate, lithium nitrate, and lithium phosphate, and also composed of Mn. Examples of the compound include manganese acetate (III) dihydrate, manganese (II) nitrate hexahydrate, manganese (II) sulfate pentahydrate, manganese (II) oxalate dihydrate, and manganese ( III) Acetylacetonate and the like.
The combination ratio (Li: Mn = X: 1) of the compound composed of Li and the compound composed of Mn used as the main raw material is not particularly limited, but is preferably 0.5 ≦ X <1, 0.5 ≦ More preferably, X ≦ 0.6.
When the combination ratio is out of the above range, a positive electrode plate having desired performance may not be efficiently manufactured.

Further, for example, as an active material precursor for finally generating LiFeO ₂ on the current collector, as a raw material, a compound made of Li and a compound made of Fe can be used in combination as a main raw material, Furthermore, other raw materials can be used in combination as required.
Examples of the compound composed of Li include lithium citrate tetrahydrate, lithium perchlorate trihydrate, lithium acetate dihydrate, lithium nitrate, and lithium phosphate, and also composed of Fe. Examples of the compound include iron (II) chloride tetrahydrate, iron (III) citrate, iron (II) acetate, iron (II) oxalate dihydrate, iron (III) nitrate nonahydrate, Examples thereof include iron (II) lactate trihydrate and iron (II) sulfate heptahydrate.
The combination ratio (Li: Fe = X: 1) of the compound composed of Li and the compound composed of Fe used as the main raw material is not particularly limited, but is preferably 1 ≦ X <2, and preferably 1 ≦ X ≦ 1. 2 is more preferable.
When the combination ratio is out of the above range, a positive electrode plate having desired performance may not be efficiently manufactured.

Further, for example, as an active material precursor for finally generating LiTiO ₂ on the current collector, a compound composed of Li and a compound composed of Ti can be used in combination as main raw materials, and further, if necessary Accordingly, other raw materials can be used in combination.
Examples of the compound composed of Li include lithium citrate tetrahydrate, lithium perchlorate trihydrate, lithium acetate dihydrate, lithium nitrate, and lithium phosphate, and also composed of Ti. Examples of the compound include titanium tetrachloride and titanium acetylacetonate.
The combination ratio of the compound composed of Li and the compound composed of Ti used as the main raw material (Li: Ti = X: 1) is not particularly limited, but is preferably 1 ≦ X <2, and preferably 1 ≦ X ≦ 1. 2 is more preferable.
When the combination ratio is out of the above range, a positive electrode plate or a negative electrode plate having desired performance may not be produced efficiently.

The total concentration of the lithium element and the other metal element in the solution containing the lithium element-containing compound and the other metal element-containing compound is 0.01 to 5 mol / L, particularly 0.1 to 2 mol / L. L is preferred. By setting the concentration to 0.01 mol / L or more, the current collector and the active material generated on the surface of the current collector can be satisfactorily adhered, and the active material can be fixed. In addition, by setting the concentration to 5 mol / L or less, it is possible to maintain a viscosity sufficient to allow the electrode active material layer forming solution to be applied to the current collector surface, and to form a uniform coating film. can do.

(Other additives)
In addition to the metal element compounds described above, other additives may be added to the electrode active material layer forming solution without departing from the spirit of the present invention. As the conductive material and other additives, the same materials as described in the description of the electrode active material layer of the present invention can be used.

When the conductive material is added to the electrode active material layer forming solution, the added amount of the conductive material is 5 parts by weight to 20 parts by weight with respect to 100 parts by weight of the active material generated on the current collector surface. Is desirable. The above description is not intended to exclude the addition of the conductive material in excess of 20 weight, but the electrode active material layer in the present invention has a good conductivity due to the presence of the dense layer, and therefore 20 weight. It is the meaning that sufficiently excellent conductivity can be exhibited by the use of a conductive material of a part or less.

(solvent)
The solvent used for dissolving the lithium element-containing compound and other metal-containing metal element compounds is not particularly limited as long as it can dissolve the metal element-containing compound including the lithium element-containing compound. Although, for example, lower alcohols having a total carbon number of 5 or less such as methanol, ethanol, isopropyl alcohol, propanol, butanol, diketones such as acetylacetone, diacetyl, benzoylacetone, ethyl acetoacetate, ethyl pyruvate, ethyl benzoylacetate, Examples thereof include ketoesters such as ethyl benzoylformate, toluene, and mixed solvents thereof.

  Next, the electrode active material layer forming solution prepared as described above is applied to any region of the current collector surface by a conventionally known coating method such as printing, spin coating, dip coating, bar coating, spray coating, etc. To form a coating film. In addition, when the current collector surface is porous, has a large number of irregularities, or has a three-dimensional structure, it can be manually applied in addition to the above method. Note that the current collector used in the present invention is preferable because corona treatment, oxygen plasma treatment, and the like can be performed in advance as necessary to further improve the film forming property of the electrode active material layer.

  The amount of the electrode active material layer-forming solution applied to the current collector can be arbitrarily determined according to the application of the electrode plate to be produced, etc., but the electrode active material layer in the present invention is very Since it can be formed thinly, when it is desired to reduce the thickness, the electrode active material layer after heating may be thinly applied so as to have a thickness of about 300 nm to 10 μm. As described above, the electrode active material layer-forming coating film containing the metal element compound that is the precursor of the active material is formed by applying the electrode layer forming solution to the substrate.

  Next, the current collector on which the coating film for forming the electrode active material layer is formed is heated. At this time, by heating at a temperature equal to or higher than the decomposition temperature of the metal element compound dissolved in the solution, a lithium transition metal composite oxide as an active material is generated on the current collector surface. Moreover, the active material is substantially free from a binder, but is bonded to the surface of the current collector, so that an electrode active material layer having good adhesion to the current collector can be obtained. Further, in this manufacturing method, two layers of a dense layer and a void forming layer are formed from the current collector side in a single heating step. The reason why the electrode active material layer-forming coating film is divided into a void-forming layer and a dense layer by heating is not clear, but in a region very close to the current collector due to heat transferred from the current collector, As a result of further promoting the decomposition of the elemental compound, it is presumed that an active material having a very small particle size and closely joined to each other may be generated. In order to satisfactorily form the dense layer, a heat source is appropriately installed on both sides of the current collector on which the electrode active material layer-forming coating film is formed on the surface, or on the side without the coating film. Heat at temperature.

Although the aspect which installs a heat source in the said both sides is not specifically limited, For example, the aspect which installs the heat source apparatus in the said both sides, or the collector by which the coating film for electrode active material layer formation was laminated | stacked in the heating furnace etc. And a mode in which both sides are heated in the same environment. Also, the mode of installing the heat source on the side of the current collector that does not have the active material-forming coating film is not particularly limited. For example, a heat source device is installed on the surface side of the current collector that does not have the coating film. Or a mode in which heating is performed on a hot plate heated to an appropriate temperature at a position where the surface of the hot plate is in contact with the surface of the current collector that does not have a coating film.

Although the said heating temperature changes with kinds of metal element compound used, decomposition | disassembly of a metal element compound is favorably performed by heating to the temperature range of 150 to 800 degreeC normally, and an active material is produced | generated. The heating method is not particularly limited, but as a heat source device, for example, a hot plate, an oven, a heating furnace, an infrared heater, a halogen heater, a hot air blower, or the like is used, or two or more are used. The method of using in combination can be mentioned. When the current collector used is planar, it is preferable to use a heating furnace, a hot plate, or the like.

[Nonaqueous electrolyte secondary battery]
Non-aqueous electrolyte secondary batteries are generally configured by providing a separator such as a polyethylene porous film between a positive electrode plate and a negative electrode plate, and storing them in a container. And the container is sealed and filled with a non-aqueous electrolyte.

(Electrode plate)
In the non-aqueous electrolyte secondary battery of the present invention, in particular, at least one of the positive electrode plate and the negative electrode plate is the above-described electrode plate for non-aqueous electrolyte secondary battery of the present invention (hereinafter simply referred to as “electrode plate of the present invention”). (Also called).
In particular, conventionally, when the negative electrode plate is composed of a carbonaceous material, it has been common to add a large amount of conductive material to the positive electrode plate in order to increase the conductivity of the positive electrode plate accordingly. For this reason, the porosity of the positive electrode plate is lowered, and the permeability of the electrolytic solution is lowered, so that it is difficult to increase the output of the battery. However, since the electrode plate of the present invention is an electrode plate capable of high output, when this is used as a positive electrode plate, without using a large amount of conductive material as in the past, or without using a conductive material at all, Enables good conductivity and high output.

  In non-aqueous electrolyte secondary batteries, the negative electrode active material used for the negative electrode plate is not a carbonaceous material, but a material capable of occluding and releasing lithium ions, such as metallic lithium and its alloys, tin, silicon, and their alloys. In the battery of this aspect, a non-aqueous electrolyte secondary battery can be manufactured by positively using the electrode plate of the present invention as a negative electrode.

  Moreover, a nonaqueous electrolyte secondary battery can also be comprised using the electrode plate of this invention for both a positive electrode plate and a negative electrode plate.

  In the non-aqueous electrolyte secondary battery of the present invention, when the electrode plate of the present invention is used in either the positive electrode or the negative electrode, the other electrode plate is used in the non-aqueous electrolyte secondary battery. A conventionally known electrode plate can be used as appropriate.

As a conventionally known positive electrode plate, generally, active material particles such as lithium transition metal composite oxide, conductive material on at least a part of the current collector surface similar to the current collector used in the electrode plate of the present invention. A solution formed by applying a solution in which a material, a binder, or the like is dispersed, drying, and pressing as necessary is used.

On the other hand, as a conventionally known negative electrode plate, a copper foil such as an electrolytic copper foil or a rolled copper foil having a thickness of about 5 to 50 μm is used as a current collector, and an electrode activity in the negative electrode plate is formed on at least a part of the current collector surface. What was formed by apply | coating a substance layer forming solution, drying, and pressing as needed is used. The electrode active material layer forming solution in the negative electrode plate generally includes an active material made of a carbonaceous material such as natural graphite, artificial graphite, amorphous carbon, carbon black, or a material obtained by adding a different element to these components, Alternatively, active materials such as lithium metal and its alloys, tin, silicon, and alloys thereof, materials that can occlude and release lithium ions, and other additives such as binders and conductive materials are dispersed as necessary. It is common to mix.

(Nonaqueous electrolyte)
The non-aqueous electrolyte used in the present invention is not particularly limited as long as it is generally used as a non-aqueous electrolyte for a non-aqueous electrolyte secondary battery, but a lithium salt is dissolved in an organic solvent. A non-aqueous electrolyte is preferably used.

Examples of the lithium salt include inorganic lithium salts such as LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiCl, and LiBr; LiB (C ₆ H ₅ ) ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiC ( Organic compounds such as SO ₂ CF ₃ ) ₃ , LiOSO ₂ CF ₃ , LiOSO ₂ C ₂ F ₅ , LiOSO ₂ C ₄ F ₉ , LiOSO ₂ C ₅ F ₁₁ , LiOSO ₂ C ₆ F ₁₃ , and LiOSO ₂ C ₇ F ₁₅ Typical examples include lithium salts.

Examples of the organic solvent used for dissolving the lithium salt include cyclic esters, chain esters, cyclic ethers, and chain ethers.
Examples of the cyclic esters include propylene carbonate, butylene carbonate, γ-butyrolactone, vinylene carbonate, 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, and γ-valerolactone.
Examples of the chain esters include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl butyl carbonate, methyl propyl carbonate, ethyl butyl carbonate, ethyl propyl carbonate, butyl propyl carbonate, propionic acid alkyl ester, Examples include malonic acid dialkyl esters and acetic acid alkyl esters.
Examples of the cyclic ethers include tetrahydrofuran, alkyltetrahydrofuran, dialkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, and 1,4-dioxolane.
Examples of the chain ethers include 1,2-dimethoxyethane, 1,2-diethoxyethane, diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and tetraethylene glycol dialkyl ether. It is done.

  As a structure of the battery manufactured using the positive electrode plate, the negative electrode plate, the separator, and the nonaqueous electrolytic solution, a conventionally known structure can be appropriately selected and used. For example, the structure which winds a positive electrode plate and a negative electrode plate in the shape of a spiral via the separator like a polyethylene porous film, and accommodates in a battery container is mentioned. As another aspect, a structure in which a positive electrode plate and a negative electrode plate cut into a predetermined shape are stacked and fixed via a separator, and this is housed in a battery container may be employed. In any structure, after the positive electrode plate and the negative electrode plate are stored in the battery container, the lead wire attached to the positive electrode plate is connected to the positive electrode terminal provided in the outer container, while the lead wire attached to the negative electrode plate Is connected to a negative electrode terminal provided in the outer container, and the battery container is further filled with a nonaqueous electrification solution and then sealed to produce a nonaqueous electrolyte secondary battery.

(Example 1)
LiNO ₃ [molecular weight: 68.95] as a starting material (solute) which generates an active material 6.9 g, and _{Co (NO 3) 2 · 6H} 2 O [ molecular weight: 291.03] using 29g of, these materials In addition to 36 g of methanol, 42 g of polyethylene glycol 400 was further added and kneaded with an Excel auto homogenizer (Nihon Seiki Seisakusho Co., Ltd.) at a rotation speed of 5000 rpm for 15 minutes to prepare an electrode active material layer forming solution.
Then, an aluminum plate having a thickness of 15 μm is prepared as a current collector, and the electrode active material prepared as described above is formed on one side of the current collector in such an amount that the thickness of the finally obtained electrode active material layer becomes 1 μm. The layer forming solution was applied with a Miya bar to form a coating film for forming an electrode active material layer.
Next, the current collector with the electrode active material layer-forming coating film formed on the surface was placed in an electric furnace at room temperature, and the temperature was raised to 600 ° C., the target temperature, over 5 hours. An electrode plate for a non-aqueous electrolyte secondary battery according to the present invention in which an electrode active material layer suitable as a positive electrode active material layer is laminated on a current collector by heating at 600 ° C. for 10 hours and taking out from the electric furnace. Obtained. The electrode plate was cut into a predetermined size (2 cm long × 2 cm wide) to obtain Example 1. In addition, the said heating was implemented in the environment heated similarly from the both surfaces side of a collector, using the muffle furnace (the Denken company make, P90) as an electric furnace.

<Adhesion test>
About Example 1, the adhesiveness test was implemented as follows, the peelability of the electrode active material layer was measured with respect to the electrical power collector, and it evaluated as follows.
When cellotape (registered trademark) (manufactured by Nichiban Co., Ltd., CT-15) is applied to the surface of the electrode active material layer and then peeled off, the transfer amount of the electrode active material layer on the cellotape side is less than 30%. ○ (Adhesion is good), △ (adhesion is poor) when it is 30% to less than 90%, × (adhesion is poor) when it is 90 to 100% . In addition,% shows the area of the transferred film fastened to the cello tape.

Example 1 obtained as described above was allowed to stand until it reached room temperature, and then with respect to the current collector surface at a magnification of 50,000 times using a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). When a cross section cut in the vertical direction was observed, a layer made of particulate LiCoO ₂ having a thickness of 1 μm was formed as an electrode active material layer on the surface of the current collector. It was confirmed that a dense layer having no void was present on the current collector side of the material layer with a very thin thickness, and a void forming layer was formed on the surface side of the electrode active material layer. Moreover, from the electron micrograph obtained by the electron microscope observation, the particle size of the particles constituting the void-forming layer in the electrode active material layer was determined using image analysis type particle size distribution measurement software (manufactured by Mount Tech Co., Ltd., MAC VIEW). 20 particles were measured, and the arithmetic average was obtained for the average minimum particle size of 5 points in ascending order of particle size and the average maximum particle size of 5 points in order of increasing particle size. Was 35 nm and the average maximum particle size was 176 nm. In addition, the graph showing the X-ray-diffraction measurement result of the electrode active material layer of Example 1 is shown in FIG. As shown in FIG. 3, it was confirmed that the electrode active material layer of the present invention was composed of LiCoO ₂ . In addition, although the presence of the particulate electrode active materials in Examples 2 to 6 shown below was confirmed by X-ray diffraction measurement in the same manner, the graph is not shown.

<Production of tripolar beaker cell>
Lithium hexafluorophosphate (LiPF ₆ ) is added as a solute to a mixed solvent of ethylene carbonate (EC) / dimethyl carbonate (DMC) (volume ratio = 1: 1), and the concentration of LiPF _{6 as} the solute is 1 mol. The non-aqueous electrolyte was prepared by adjusting the concentration to be / L.
Example 1 (2 cm long × 2 cm wide, weight of positive electrode active material contained: 0.9 mg / 4 cm ² ) prepared as described above as a positive electrode plate was used as a working electrode, and a counter electrode plate and a reference electrode plate on a nickel mesh A metal lithium plate having a metal lithium foil bonded thereto, the non-aqueous electrolyte prepared above as an electrolyte, and a spot welder in advance for each electrode plate (positive electrode plate, counter electrode plate, reference electrode plate) After attaching the lead wire (nickel wire), a tripolar beaker cell was assembled, and this was designated as Example Test Cell 1. The example test cell 1 was subjected to the following charge / discharge test.

<Charge / discharge test>
In Example Test Cell 1 which is a tripolar beaker cell prepared as described above, first, in order to conduct a discharge test of the working electrode, the battery was fully charged as in the following charge test of Example Test Cell 1.

Charging test:
Example Test cell 1 was charged at a constant current (52 μA) under a 25 ° C. environment until the voltage reached 4.2 V. After the voltage reached 4.2 V, the voltage was 4.2 V. The current (discharge rate: 1C) was decreased until the current became 5% or less, and the battery was charged at a constant voltage, fully charged, and then suspended for 10 minutes. Here, “1C” means a current value (current value that reaches a discharge end voltage) at which constant current discharge is performed using the tripolar beaker cell and discharge is completed in one hour. . The constant current was set such that a theoretical discharge amount of 130 mAh / g of lithium cobaltate as an active material was discharged in one hour at the working electrode in the example test cell 1.

Discharge test:
Thereafter, the fully charged example test cell 1 was subjected to a constant current (52 μA) (discharge) in an environment of 25 ° C. until the voltage changed from 4.2 V (full charge voltage) to 3.0 V (discharge end voltage). A constant current discharge at a rate of 1 C), the cell voltage (V) on the vertical axis, the discharge time (h) on the horizontal axis, a discharge curve is created, and the working electrode (electrode plate for positive electrode of Example 1) The discharge capacity (mAh) was determined and converted to the discharge capacity (mAh / g) per unit weight of the working electrode.

  Subsequently, 20 times the constant current (1.04 mA) (discharge rate: based on the constant current discharge test at a constant current (52 μA) (discharge rate: 1 C, discharge end time: 1 hour) performed as described above. 20C, discharge end time: 3 minutes, 50 times constant current (2.60 mA) (discharge rate: 50 C, discharge end time: 1.2 minutes), 100 times constant current (5.20 mA) (discharge rate: 100C, discharge end time: 0.6 minutes), a constant current discharge test was performed in the same manner, and the discharge capacity (mAh) of the working electrode at each discharge rate was determined. From this, the discharge capacity per unit weight (mAh) / G) was converted.

<Calculation of discharge capacity maintenance rate (%)>
In order to evaluate the output characteristics (discharge rate characteristics) of the working electrode, each discharge capacity (mAh / g) per unit weight at each discharge rate obtained as described above is used, and the discharge capacity is maintained according to the above-described formula 1. The rate (%) was determined. The discharge capacity (mAh / g) and discharge capacity retention rate (%) per unit weight obtained by the above discharge test are all shown in Table 1.

(Comparative Example 1)
80 parts by weight of LiCoO ₂ powder having an average particle diameter of 10 μm as a raw material of the positive electrode active material, 10 parts by weight of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., Denka Black) as a conductive agent, and PVDF (manufactured by Kureha Co., KF #) as a binder 1100) Add 10 parts by weight of organic solvent NMP (Mitsubishi Chemical Co., Ltd.), disperse, and rotate at 5000 rpm with an Excel Auto Homogenizer (Nippon Seiki Seisakusyo Co., Ltd.) so that the solid concentration is 55% by weight. The slurry was stirred for 15 minutes to prepare a slurry-like coating composition for a positive electrode active material layer. And the coating amount of the coating composition for positive electrode active material layers after drying on the 15-micrometer-thick aluminum foil used for the positive electrode active material coating composition prepared above as a positive electrode collector is 50 g / It was applied so that the m ^2, using an oven, dried for 20 minutes in an air atmosphere of 120 ° C., to form an electrode active material layer for the positive electrode on the current collector surface. Furthermore, after pressing using a roll press machine so that the coating density of the formed electrode active material layer is 2.0 g / cm ³ (thickness of the positive electrode active material layer: 25 μm), a predetermined size is obtained. (2 cm × 2 cm) and vacuum-dried at 120 ° C. for 12 hours to produce an electrode plate for a non-aqueous electrolyte secondary battery positive electrode. As a result of performing an adhesion test on Comparative Example 1 in the same manner as in Example 1, the adhesion evaluation was Δ.

<Production of tripolar beaker cell>
A tripolar beaker cell was assembled in the same manner as in Example Test Cell 1 except that Comparative Example 1 produced as described above was used as the working electrode, and this was designated as Comparative Example Test Cell 1.

<Charge test and discharge test>
For Comparative Test Cell 1, the constant current at each discharge rate was constant current (1.2 mA) (discharge rate: 1 C, discharge end time: 1 hour), constant current (23.4 mA) (discharge rate: 20 C, discharge) End time: 3 minutes), constant current (58.5 mA) (discharge rate: 50 C, discharge end time: 1.2 minutes), constant current (117.0 mA) (discharge rate: 100 C, discharge end time: 0.6 Except for the above, the charge test and the discharge test were conducted in the same manner as in the example test cell 1 to determine the discharge capacity (mAh) of the working electrode at each discharge rate, and from this, the discharge capacity per unit weight (mAh) / G) was converted. Similarly to the example test cell 1, the discharge capacity retention rate (%) was obtained using the calculation formula 1. The results are summarized in Table 1.

(Example 2)
6.9 g of LiNO ₃ [molecular weight: 68.95] and cobalt (II) acetylacetonate dihydrate (manufactured by Kanto Chemical Co., Inc.) [molecular weight: 293.18] as raw materials (solutes) for generating an active material An electrode active material layer forming solution was prepared in the same manner as in Example 1 except that 30 g was used.
Then, a coating film for forming an electrode active material layer was formed, heated and cut using the same method and conditions as in Example 1 except that the applicator was applied in an amount of 0.5 mil instead of the Miya bar. An electrode plate for a positive electrode for an electrolyte secondary battery was prepared and used as Example 2. About Example 2, as a result of performing the adhesive test similarly to Example 1, adhesive evaluation was (circle).

When the cross section cut in the direction perpendicular to the current collector surface was observed in the same manner as in Example 1, the sample obtained in Example 2 was allowed to stand until it reached room temperature, and an electrode was formed on the current collector surface. As the active material layer, a layer made of particulate LiCoO ₂ having a thickness of 1 μm is formed, and a dense layer without voids on the current collector side of the electrode active material layer has a very thin thickness. It was confirmed that a void forming layer was formed on the surface side of the electrode active material layer. Moreover, when the particle size of the particles constituting the electrode active material layer was determined in the same manner as in Example 1, the average minimum particle size was 20 nm and the average maximum particle size was 190 nm.

<Charge test and discharge test>
Triodes were prepared in the same procedure as in Example 1 except that Example 2 (length 2 cm × width 2 cm, weight of positive electrode active material contained: 0.9 mg / 4 cm ² ) was used as a working electrode as a positive electrode plate. A type beaker cell was prepared and designated as Example Test Cell 2. A charge / discharge test was conducted in the same manner as in Example 1. The constant current in the charge / discharge test of the example test cell 2 was 52 μA. The discharge capacity per unit weight (mAh / g) and discharge capacity retention rate (%) obtained by the above discharge test are all shown in Table 1.

(Example 3)
LiNO ₃ [molecular weight: 68.95] as a starting material (solute) which generates an active material 3.3 g, and _{Co (NO 3) 2 · 6H} 2 O [ molecular weight: 291.03] performed except for using 10g of An electrode active material layer forming solution was prepared in the same manner as in Example 1.
And the coating film for electrode active material layer formation was formed on the same method and conditions as Example 1 except having changed the application quantity into the quantity from which the thickness of the electrode active material layer finally obtained will be 300 nm. By heating and cutting, an electrode plate for a non-aqueous electrolyte secondary battery positive electrode of the present invention was produced, and Example 3 was obtained. About Example 3, as a result of performing the adhesive test similarly to Example 1, adhesive evaluation was (circle).

Example 3 obtained above was allowed to stand until it reached room temperature, and a section cut in a direction perpendicular to the current collector surface was observed in the same manner as in Example 1. As a result, an electrode was formed on the current collector surface. A layer made of particulate LiCoO ₂ having a thickness of 300 nm is formed as the active material layer, and a dense layer without voids on the current collector side of the electrode active material layer has a very thin thickness. It was confirmed that a void forming layer was formed on the surface side of the electrode active material layer. Moreover, when the particle size of the particles constituting the electrode active material layer was determined in the same manner as in Example 1, the average minimum particle size was 32 nm and the average maximum particle size was 151 nm.

<Charge test and discharge test>
Triodes were prepared in the same procedure as in Example 1 except that Example 3 (length 2 cm × width 2 cm, weight of positive electrode active material contained: 0.34 mg / 4 cm ² ) was used as a working electrode as a positive electrode plate. A type beaker cell was prepared and designated as Example Test Cell 3. A charge / discharge test was conducted in the same manner as in Example 1. The constant current in the charge / discharge test of the example test cell 3 was 20 μA. The discharge capacity per unit weight (mAh / g) and discharge capacity retention rate (%) obtained by the above discharge test are all shown in Table 1.

Example 4
LiNO ₃ [molecular weight: 68.95] as a starting material (solute) which generates an active material; 6.9 g and _{Co (NO 3) 2 · 6H} 2 O [ molecular weight: 291.03]; using 29 g, these materials An electrode active material layer forming solution was prepared in the same manner as in Example 1 except that 18 g of methanol was dissolved and polyethylene glycol 400; 20 g was further added.
And the coating film for electrode active material layer formation was formed on the same method and conditions as Example 1 except having changed into the quantity from which the thickness of the electrode active material layer finally obtained becomes 10 micrometers. By heating and cutting, an electrode plate for a non-aqueous electrolyte secondary battery positive electrode of the present invention was produced, and Example 4 was obtained. About Example 4, as a result of performing the adhesive test similarly to Example 1, adhesive evaluation was (circle).

Example 4 obtained above was allowed to stand until it reached room temperature, and a cross section cut in a direction perpendicular to the current collector surface was observed in the same manner as in Example 1. As a result, an electrode was formed on the current collector surface. A layer made of particulate LiCoO ₂ having a thickness of 10 μm is formed as the active material layer, and a dense layer without voids on the current collector side of the electrode active material layer has a very thin thickness. It was confirmed that a void forming layer was formed on the surface side of the electrode active material layer. Further, when the particle diameter of the particles constituting the electrode active material layer was determined in the same manner as in Example 1, the average minimum particle diameter was 97 nm and the average maximum particle diameter was 803 nm.

<Charge test and discharge test>
Triodes were prepared in the same procedure as in Example 1 except that Example 4 (length 2 cm × width 2 cm, weight of positive electrode active material contained: 7.15 mg / 4 cm ² ) was used as a working electrode as a positive electrode plate. A type beaker cell was prepared and designated as Example Test Cell 4. A charge / discharge test was conducted in the same manner as in Example 1. In addition, the constant current in the charging / discharging test of Example test cell 4 was 410 μA. The discharge capacity per unit weight (mAh / g) and discharge capacity retention rate (%) obtained by the above discharge test are all shown in Table 1.

(Example 5)
LiNO ₃ [molecular weight: 68.95] as a starting material (solute) which generates an active material 6.9 g, and _{Co (NO 3) 2 · 6H} 2 O [ molecular weight: 291.03] using 29g of, these materials An electrode active material layer forming solution was prepared in the same manner as in Example 1 except that 20 g of polyethylene glycol 400 and 1.2 g of acetylene black (Denka Black manufactured by Denki Kagaku Kogyo Co., Ltd.) were added. did.
Then, the coating amount was changed to an amount such that the finally obtained electrode active material layer had a thickness of 10 μm, and the heating condition was raised from room temperature to 500 ° C. in an electric furnace over 5 hours, to 500 ° C. The electrode active material layer-forming coating film was formed, heated and cut using the same method and conditions as in Example 1 except that the sample was held for 0.2 hours and removed from the electric furnace. An electrode plate for a non-aqueous electrolyte secondary battery positive electrode was prepared and used as Example 5. About Example 5, as a result of performing the adhesive test similarly to Example 1, adhesive evaluation was (circle).

Example 5 obtained above was allowed to stand until it reached room temperature, and when a cross section cut in a direction perpendicular to the current collector surface was observed in the same manner as in Example 1, an electrode was formed on the current collector surface. A layer made of particulate LiCoO ₂ having a thickness of 10 μm is formed as the active material layer, and a dense layer without voids on the current collector side of the electrode active material layer has a very thin thickness. It was confirmed that a void forming layer was formed on the surface side of the electrode active material layer. Moreover, when the particle size of the particles constituting the electrode active material layer was determined in the same manner as in Example 1, the average minimum particle size was 18 nm and the average maximum particle size was 766 nm.

<Charge test and discharge test>
Three electrodes were prepared in the same procedure as in Example 1, except that Example 5 (length 2 cm × width 2 cm, weight of positive electrode active material contained: 6.8 mg / 4 cm ² ) was used as the working electrode as the positive electrode plate. A type beaker cell was prepared and designated as Example Test Cell 5. A charge / discharge test was conducted in the same manner as in Example 1. The constant current in the charge / discharge test of the example test cell 5 was 390 μA. The discharge capacity per unit weight (mAh / g) and discharge capacity retention rate (%) obtained by the above discharge test are all shown in Table 1.

(Example 6)
10.5 g of TiCl ₄ [molecular weight: 189.68] and 3.06 g of LiNO ₃ [molecular weight: 68.95] were used as raw materials (solutes) for generating an active material, and 36 g of methanol was added to these raw materials. An electrode active material layer forming solution was prepared in the same manner as in Example 1 except that 42 g of polyethylene glycol 400 was added.
And the coating film for electrode active material layer formation was formed on the same method and conditions as Example 1 except having changed the application quantity into the quantity from which the thickness of the electrode active material layer finally obtained becomes 700 nm. By heating and cutting, an electrode plate for a non-aqueous electrolyte secondary battery negative electrode of the present invention was produced, and Example 6 was obtained. About Example 6, as a result of performing the adhesive test similarly to Example 1, adhesive evaluation was (circle).

Example 6 obtained above was allowed to stand until it reached room temperature, and when a cross section cut in a direction perpendicular to the current collector surface was observed in the same manner as in Example 1, an electrode was formed on the current collector surface. A layer made of particulate Li ₄ Ti ₅ O ₁₂ having a thickness of 700 μm is formed as the active material layer, and a dense layer without voids is formed on the current collector side of the electrode active material layer. It was confirmed that there was a very thin thickness and that a void forming layer was formed on the surface side of the electrode active material layer. Moreover, when the particle size of the particles constituting the electrode active material layer was determined in the same manner as in Example 1, the average minimum particle size was 13 nm and the average maximum particle size was 165 nm.

<Charge test and discharge test>
The same procedure as in Example 1 except that Example 6 (2 cm long × 2 cm wide, weight of positive electrode active material contained: 0.7 mg / 4 cm ² ) prepared as the negative electrode plate was used as the working electrode. A three-electrode beaker cell was prepared, and Example Test Cell 6 was obtained. A charge / discharge test was conducted in the same manner as in Example 1. More specifically, in a 25 ° C. environment, constant current charging is performed with a constant current (54 μA) until the voltage reaches 1.3, and after the voltage reaches 1.3 V, the voltage decreases to 1.3 V. In order not to fall below, the current (discharge rate: 1C) was decreased until it became 5% or less, and the battery was charged at a constant voltage, fully charged, and then rested for 10 minutes. The constant current was set so that a theoretical discharge amount of 170 mAh / g of lithium titanate as an active material was discharged in one hour at the working electrode in the example test cell 6.
Thereafter, the fully charged example test cell 6 was subjected to a constant current (54 μA) (discharge) under an environment of 25 ° C. until the voltage was changed from 1.3 V (full charge voltage) to 2.0 V (discharge end voltage). A constant current discharge at a rate of 1 C), the cell voltage (V) on the vertical axis, the discharge time (h) on the horizontal axis, a discharge curve is created, and the working electrode (electrode plate for negative electrode of Example 6) The discharge capacity (mAh) was determined and converted to the discharge capacity (mAh / g) per unit weight of the working electrode. The discharge capacity per unit weight (mAh / g) and discharge capacity retention rate (%) obtained by the above discharge test are all shown in Table 1.

(Example 7)
The positive electrode plate of Example 1 and the negative electrode plate of Example 6 were combined to produce a tripolar beaker cell in the same procedure as in Example 1, and a charge / discharge test was performed as follows. The constant current in the charge / discharge test was 52 μA. The discharge capacity per unit weight (mAh / g) and discharge capacity retention rate (%) obtained by the above discharge test are all shown in Table 1.

<Charge test and discharge test>
The test cell 7 was charged at a constant current (52 μA) until the voltage reached 3.3V in an environment of 25 ° C. After the voltage reached 3.3V, the voltage was 3.3V. The current (discharge rate: 1C) was decreased until the current became 5% or less, and the battery was charged at a constant voltage, fully charged, and then suspended for 10 minutes.
Thereafter, the fully-charged example test cell 7 was subjected to a constant current (52 μA) (discharge) until the voltage changed from 3.3 V (full charge voltage) to 1.0 V (discharge end voltage) in an environment of 25 ° C. A constant current discharge at a rate of 1 C), the cell voltage (V) on the vertical axis, the discharge time (h) on the horizontal axis, a discharge curve is created, and the working electrode (electrode plate for positive electrode of Example 1) The discharge capacity (mAh) was determined and converted to the discharge capacity (mAh / g) per unit weight of the working electrode.

(Comparative Example 2)
A positive electrode plate was prepared in the same manner as in Comparative Example 1 except that PVDF (manufactured by Kureha, KF # 1100) was 7 parts by weight as a binder, and Comparative Example Test Cell 2 was prepared and evaluated. . Evaluation results such as the discharge capacity retention rate (%) are summarized in Table 1.

(Comparative Example 3)
An experiment was performed in the same manner as in Comparative Example 1 except that PVDF (manufactured by Kureha, KF # 1100) was used as 0 part by weight as a binder. However, since the binder was not added, the electrode active material layer did not adhere to the current collector, and the tripolar beaker cell could not be tested.

(Reference Example 1)
As a heating means for the current collector having the electrode active material layer-forming coating film formed on the surface, it was heated to 400 ° C. instead of heating at 600 ° C. for 10 hours (heating time 5 hours) using an electric furnace. In the hot plate, the current collector was directly placed on the hot plate so that the coating surface side was in contact with the hot plate, heated for 20 minutes, and then continuously using an electric furnace at 600 ° C. for 10 hours (heating time) 5 hours) An electrode plate for a non-aqueous electrolyte secondary battery positive electrode was prepared in the same manner and under the same conditions as in Example 1 except that the sample was heated. As a result of performing an adhesion test on Reference Example 1 in the same manner as in Example 1, the adhesion evaluation was “good”.

The reference example 1 obtained above was allowed to stand until it reached room temperature, and a section cut in a direction perpendicular to the current collector surface was observed in the same manner as in Example 1. As a result, an electrode was formed on the current collector surface. A LiCoO ₂ layer having a thickness of 1 μm was formed as an active material layer. However, the electrode active material layer was confirmed to have voids throughout, and the dense layer present in the present invention was not confirmed. Moreover, when the particle size of the particles constituting the electrode active material layer was determined in the same manner as in Example 1, the average minimum particle size was 60 nm and the average maximum particle size was 163 nm.

<Charge test and discharge test>
A tripolar beaker cell was produced in the same procedure as in Example 1 except that Reference Example 1 was used as a working electrode which was a positive electrode plate, and designated as Reference Example Test Cell 1. A charge / discharge test was conducted in the same manner as in Example 1. The constant current in the charge / discharge test of the reference example test cell 1 was 53 μA. The discharge capacity per unit weight (mAh / g) and discharge capacity retention rate (%) obtained by the above discharge test are all shown in Table 1.

As described above, in Examples 1 to 6 and Comparative Examples 1 and 2, when the discharge rate was 1 C, the discharge capacity retention rate was 100%. However, when the discharge rate was increased, Comparative Examples 1 and 2 It was shown that the reduction of the discharge capacity retention rate was remarkable and the charge / discharge performance was low.
On the other hand, Examples 1 to 6 showed a high discharge capacity retention rate even when the discharge rate was increased, and it was confirmed that the charge / discharge performance was improved in the present invention.

  Further, in Comparative Example 1 and Comparative Example 2 in which the addition amount of the binder is different, the charge / discharge performance of Comparative Example 2 in which the addition amount of the binder is small is higher, and the presence of the binder is the charge / discharge of the electrode. It was shown to be directly related to performance.

  In addition, it was confirmed that Reference Example 1 produced in the same manner as Example 1 except that the heating method was changed in the manufacturing process has a greatly improved discharge capacity retention rate compared to the comparative example. However, as compared with Example 1 in which the compound and film thickness constituting the active material are exactly the same, the discharge capacity retention rate is slightly low, and the charge / discharge performance of the electrode active material layer of the present invention is due to the presence of the dense layer. Was shown to be particularly good.

  In Example 7 where the cell was assembled using Example 1 prepared as the positive electrode plate and Example 6 prepared as the negative electrode plate, and the charge / discharge performance was confirmed, it was confirmed that the charge / discharge performance was also high. It was shown that the non-aqueous electrolyte secondary battery using the electrode of the present invention has high charge / discharge performance. That is, the result of Example 7 is that the rate characteristic of the negative electrode of Example 6 used as the counter electrode is as high as that of metallic lithium, so that the performance of Example 1 of the present invention at the working electrode was evaluated well. I can say that. Therefore, in Example 7, the performance of any of Example 1 and Example 6 was shown, and it was shown that the charge / discharge performance of the nonaqueous electrolyte secondary battery using these was high.

It is an electron micrograph of the cross section of the electrode plate for nonaqueous electrolyte secondary batteries of this invention. It is an electron micrograph of the upper surface of the electrode plate for nonaqueous electrolyte secondary batteries (gap formation layer side) of the present invention. 3 is a graph showing the results of an X-ray diffractometer (XRD) of a positive electrode active material layer in Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode plate for non-aqueous electrolyte secondary battery solution 2 Current collector 3 Dense layer 4 Void forming layer 5 Electrode active material layer 6 Void

Claims (14)

An electrode plate for a non-aqueous electrolyte secondary battery comprising an electrode active material layer composed of an active material on at least a part of the surface of a current collector,
The electrode active material layer includes at least two layers of a dense layer and a void forming layer from the current collector side,
The dense layer is directly on the current collector and the gap forming layer,
The dense layer is a layer formed by a layer structure in which the active materials are continuously present when the active materials are bonded to each other, and is substantially free of voids.
On the other hand, the void-forming layer is formed of a layer structure in which the active materials are continuously bonded to each other by partially joining the active materials, and the void-forming layer has a void having voids through which the electrolytic solution can permeate. A layer of quality,
The active material constituting the dense layer and the void forming layer is a lithium transition metal composite oxide,
Ri transition metal and allogeneic der contained in the lithium transition metal composite oxide as an active material for constituting the transition metal and the gap forming layers included in the lithium-transition metal composite oxide as an active material for constituting the dense layer ,
Characterized in arithmetic mean of the measured values in the electron microscopic observation, an average minimum particle size of the active material constituting the gap forming layers is less than or 10 nm 100 nm, and an average maximum particle diameter of 900nm less der Rukoto than 150nm An electrode plate for a non-aqueous electrolyte secondary battery. 2. The electrode plate for a non-aqueous electrolyte secondary battery according to claim 1, wherein the electrode active material layer has a thickness of 300 nm to 10 μm. 3. The discharge capacity maintenance ratio is 50% or more at a discharge rate of 50C or more, assuming that the discharge capacity maintenance ratio when discharging at a discharge rate of 1C is 100%. 2. The electrode plate for a non-aqueous electrolyte secondary battery according to item 1. The electrode plate for a nonaqueous electrolyte secondary battery according to any one of claims 1 to 3 , wherein the electrode active material layer contains a conductive material. The thickness of the electrode active material layer, a non-aqueous electrolyte secondary battery electrode plate according to any one of claims 1 to 4, characterized in that at 1μm or more. The electrode thickness of the active material layer, according to claim 1, 3, 4, or non-aqueous electrolyte secondary battery electrode plate according to any one of 5, wherein the at 10μm or more. The electrode plate for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 6 , wherein the active material is lithium titanate. A negative electrode plate for a non-aqueous electrolyte secondary battery comprising an electrode active material layer composed of an active material on at least a part of the surface of a current collector,
The electrode active material layer includes at least two layers of a dense layer and a void forming layer from the current collector side,
The dense layer is directly on the current collector and the gap forming layer,
The dense layer is a layer formed by a layer structure in which the active materials are continuously present when the active materials are bonded to each other, and is substantially free of voids.
On the other hand, the void-forming layer is formed of a layer structure in which the active materials are continuously bonded to each other by partially joining the active materials, and the void-forming layer has a void having voids through which the electrolytic solution can permeate. A layer of quality,
The active material constituting the dense layer and the void forming layer is a lithium transition metal composite oxide,
The transition metal contained in the lithium transition metal composite oxide, which is the active material constituting the dense layer, and the transition metal contained in the lithium transition metal composite oxide, which is the active material constituting the void forming layer, are the same type. A negative electrode plate for a non-aqueous electrolyte secondary battery. Preparing an electrode active material layer forming solution in which at least one lithium element-containing compound and one or more metal element-containing compounds including a transition metal are dissolved;
The electrode active material layer forming solution is applied to at least a part of the current collector surface to form a coating film,
Next, a heat source is installed on both sides of the current collector or on the side of the current collector that does not have the coating film, and heated at a temperature of 150 ° C. or higher. A method for producing an electrode plate for a non-aqueous electrolyte secondary battery, wherein an electrode active material layer is formed by forming a lithium transition metal composite oxide on the surface of the current collector. The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to claim 9 , wherein the electrode active material layer forming solution contains a conductive material. The method for producing an electrode plate for a non-aqueous electrolyte secondary battery according to claim 9 or 10 , wherein an electrode active material layer having a thickness of 1 µm or more is formed. The method for producing an electrode plate for a nonaqueous electrolyte secondary battery according to claim 11 , wherein an electrode active material layer having a thickness of 10 μm or more is formed. A non-aqueous electrolyte secondary battery comprising a positive electrode plate, a negative electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolyte containing a non-aqueous solvent,
The nonaqueous electrolyte secondary battery, wherein at least one of the positive electrode plate and the negative electrode plate is the electrode plate for a nonaqueous electrolyte secondary battery according to any one of claims 1 to 7. battery. A non-aqueous electrolyte secondary battery comprising a positive electrode plate, a negative electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolyte containing a non-aqueous solvent,
The said negative electrode plate is a negative electrode plate for nonaqueous electrolyte secondary batteries of Claim 8, The nonaqueous electrolyte secondary battery characterized by the above-mentioned.