JP2006216271A - Active material and nonaqueous electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive electrode active material capable of enhancing its filling ability by making the shape of the positive electrode active material spherical, and a nonaqueous electrolyte secondary battery using the material. <P>SOLUTION: The aspect ratio of the positive electrode active material is not more than 1.5 at the cumulative percentage of 80%, and when measuring TAP density of the positive electrode active material by tapping it 20 times and 300 times, the ratio of the TAP density obtained by tapping it 20 times to the TAP density obtained by tapping it 300 times is in the range of not less than 0.92 and not more than 1. Thereby, filling ability of the positive electrode active material is enhanced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a positive electrode active material capable of improving fillability and a nonaqueous electrolyte secondary battery using the same.

  In recent years, various portable electronic devices such as a camera-integrated VTR, a mobile phone, and a laptop computer have appeared, and the demand is rapidly expanding. As these electronic devices become smaller and lighter, research and development for improving the energy density of batteries as portable power sources, particularly secondary batteries, are being actively promoted. Among them, lithium ion secondary batteries have higher energy density than conventional water-based electrolyte secondary batteries, such as lead batteries, nickel cadmium batteries, and nickel metal hydride batteries. The scope of application is expected to be expanded by improving the performance. In addition, as electronic devices become more sophisticated, power consumption tends to increase, and there is a demand for discharging with a larger current.

  As a positive electrode active material used for a lithium ion battery, a lithium / cobalt composite oxide having a layered rock salt structure, a lithium / nickel composite oxide, a lithium / manganese composite oxide having a spinel structure, and the like have been put into practical use. Although each has advantages and disadvantages, lithium-cobalt composite oxides are currently widely used because they have the best balance of capacity, cost, and thermal stability.

  For example, the following Patent Document 1 discloses that primary particles having an average particle diameter of 0.1 μm or more and 15 μm or less formed by agglomeration of primary particles having an average particle diameter of 0.01 μm or more and 5.0 μm or less that can obtain good cycle characteristics. Non-aqueous secondary batteries made of aggregates are described.

JP-A-6-325791

  In recent years, miniaturization of nonaqueous electrolyte secondary batteries has been demanded. In order to meet this requirement, it is important to improve the fillability of the electrode.

  Accordingly, an object of the present invention is to provide a positive electrode active material capable of increasing the filling property by making the shape of the positive electrode active material spherical, and a nonaqueous electrolyte secondary battery using the same.

  The present inventor has intensively studied to solve the above-described problems of the prior art. According to the knowledge of the present inventor, the lithium cobalt oxide composite oxide has a relatively flat particle shape after firing and pulverization, and the filling property becomes low.

  Therefore, the present inventor has intensively studied through experiments to improve the filling property of the positive electrode active material. As a result, the present inventor came to recall the following. That is, when the aspect ratio of the positive electrode active material is 1.5 or less at a cumulative 80% and the 20 times TAP density and the 300 times TAP density of the positive electrode active material are measured, the 20 times TAP density and the 300 times TAP density are measured. It has been recalled that the filling property of the positive electrode active material can be improved by using a positive electrode active material characterized in that the ratio to the density is in the range of 0.92 or more and 1 or less. The present invention has been devised based on the above studies.

In order to solve the above-described problems, the present invention provides:
A positive electrode active material capable of doping and dedoping lithium,
The aspect ratio of the positive electrode active material is in the range of 1 to 1.5 at a cumulative 80%, and
When the 20-time TAP density and the 300-time TAP density of the positive electrode active material are measured, the ratio of the 20-time TAP density to the 300-time TAP density is in the range of 0.92 to 1 inclusive. It is a substance.

This invention
A non-aqueous electrolyte secondary battery using a positive electrode active material capable of doping and dedoping lithium,
The aspect ratio of the positive electrode active material is in the range of 1 to 1.5 at a cumulative 80%, and
When the 20-fold TAP density and the 300-fold TAP density of the positive electrode active material are measured, the ratio of the 20-fold TAP density to the 300-fold TAP density is in the range of 0.92 or more and 1 or less. It is an electrolyte secondary battery.

  According to the present invention, the filling property of the positive electrode active material can be improved by making the positive electrode active material spherical. As a result, the volume density can be improved and the battery capacity can be increased.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view showing a configuration example of a nonaqueous electrolyte secondary battery according to an embodiment of the present invention. As shown in FIG. 1, this non-aqueous electrolyte secondary battery includes a wound electrode element 1 accommodated in an exterior material 2 made of a moisture-proof laminate film, and sealed around the wound electrode element 1 by welding. Stop. The wound electrode element 1 is provided with leads 3 and 4, and these leads 3 and 4 are sandwiched by the exterior material 2 and pulled out to the outside.

  The packaging material 2 has, for example, a laminated structure in which an adhesive layer, a metal layer, and a surface protective layer are sequentially laminated. The adhesive layer is made of a polymer film, and examples of the material constituting the polymer film include polypropylene (PP) and polyethylene (PE). The metal layer is made of a metal foil, and an example of a material constituting the metal foil is aluminum (Al). Examples of the material constituting the surface protective layer include nylon (Ny) and polyethylene terephthalate (PET). The surface on the adhesive layer side is a storage surface on the side where the wound electrode element 1 is stored.

  FIG. 2 is an exploded perspective view showing a configuration example of the wound electrode element 1. FIG. 3 is a cross-sectional view showing a configuration example of the wound electrode element 1. As shown in FIG. 2, the wound electrode element 1 includes a strip-shaped positive electrode 11, a strip-shaped negative electrode 12 disposed opposite to the positive electrode 11, and a gel formed on both surfaces of the positive electrode 11 and the negative electrode 12. An electrolyte layer 14 and a separator 13 interposed between the positive electrode 11 and the negative electrode 12 on which the gel electrolyte layer 14 is formed are provided. Specifically, the wound electrode element 1 includes a positive electrode 11 on which a gel electrolyte layer 14 is formed and a negative electrode 12 on which a gel electrolyte layer 14 is formed in a number of turns in the longitudinal direction via a separator 13. Turn.

<Positive electrode>
As shown in FIG. 3, the positive electrode 11 includes a strip-shaped positive electrode current collector 11a and a positive electrode mixture layer 11b formed on both surfaces of the positive electrode current collector 11a. The positive electrode current collector 11a is a metal foil made of, for example, aluminum. The positive electrode mixture layer 11b includes a positive electrode active material, a binder (binder), a conductive agent, and poly (oxyethylene) or poly (oxypropylene).

  The positive electrode active material is a lithium transition metal composite oxide, which is a composite oxide of lithium and a transition metal, and preferably has a range of 1 to 1.5 when the aspect ratio is 80% cumulative, and 20 A powder having a ratio of the TAP density to the 300 TAP density in the range of 0.92 to 1 is used. By using the positive electrode active material in the above range, the filling property can be improved as compared with the conventional case.

  The positive electrode active material is a lithium transition metal composite oxide that is a composite oxide of lithium and a transition metal, and more preferably in the range of 1 to 1.3 when the aspect ratio is 80% cumulative. In addition, a powder having a ratio of 20 times TAP density to 300 times TAP density in a range of 0.92 to 1 is used. By using the positive electrode active material in the above range, the filling property can be further improved as compared with the conventional case.

Here, the aspect ratio refers to a value obtained by dividing the major axis (L) of the primary particle or the secondary particle by the minor axis (S), and is represented by the following formula.
Aspect ratio = L / S (Formula 1)

  As for the aspect ratio, a particle image is photographed with a scanning electron microscope (SEM), and several tens of images are randomly selected from the image, and the major axis and the minor axis are measured. Then, a histogram is created from the result, and a cumulative value of 80% is obtained.

  The TAP density is measured by the method standardized in JISK1201-1.

Specifically, for example, a general formula Li [Li _x Mn _(1-xyz) Ni _y M _z ] O _(2-a) F _b can be used as the lithium transition metal composite oxide.

For example, the positive electrode active material includes lithium, nickel, manganese, at least one first element in the group consisting of elements of Group 2 to Group 14, and oxygen, and includes nickel, manganese, and the composition of the 1 element general formula _{Li [Li x Mn (1-} xyz) Ni y M z] O (2-a) lithium transition metal composite oxide having a composition of F _b, and lithium, among nickel and cobalt at least one second element, the general formula _{Li c M (1-d)} M 'd O lithium transition metal composite oxide having a composition of _(2-e) F _f, formula Li _s Mn _2-t M of A positive electrode active material characterized by containing a spinel-type lithium manganese oxide represented by “ _t O _u F _v or a lithium transition metal composite phosphate having a composition of the general formula LiM ′” PO ₄ is used. be able to.

  As the binder, for example, polytetrafluoroethylene, polyvinylidene fluoride (PVdF), polyethylene, or the like can be used. As the conductive agent, for example, carbon powder such as graphite and carbon black can be used.

<Negative electrode>
As shown in FIG. 3, the negative electrode 12 includes a strip-shaped negative electrode current collector 12a and a negative electrode mixture layer 12b formed on both surfaces of the negative electrode current collector 12a. The negative electrode current collector 12a is a metal foil made of, for example, copper. The negative electrode mixture layer 12b includes a negative electrode active material, a binder, and a conductive agent.

  The negative electrode active material is not particularly limited, and for example, any metal can be used as long as it is a lithium metal, a metal that can form an alloy with lithium and its alloy, or a material that is doped with lithium. For example, non-graphitizable carbon, artificial graphite, natural graphite, pyrolytic carbon, coke (pitch coke, needle coke, petroleum coke, etc.), graphite, glassy carbon, organic polymer compound fired body ( Carbonaceous materials such as phenol resins, furan resins and the like that are calcined and carbonized at an appropriate temperature), carbon fibers, activated carbon, carbon blacks, and the like can be used. Further, oxides such as iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, titanium oxide, tin oxide, etc. that dope and dedope lithium at a relatively low potential, and other nitrides can be used as well.

  As the binder, for example, polytetrafluoroethylene, polyvinylidene fluoride (PVdF), polyethylene, or the like can be used. As the conductive agent, for example, carbon powder such as graphite and carbon black can be used.

<Electrolyte>
The gel electrolyte is formed by impregnating a matrix polymer with a nonaqueous solvent and an electrolyte salt. Any nonaqueous solvent can be used as long as it is used for this type of battery. For example, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, γ-butyllactone, γ-valerolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, , 3-dioxolane, 4 methyl 1,3 dioxolane, diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propionitrile, acetate ester, butyrate ester, propionate ester and the like. These may be used alone or as a mixture of two or more.

  As the matrix of the gel electrolyte, various polymers can be used as long as they can be gelated by absorbing the non-aqueous solvent described above. For example, fluorine-based polymers such as poly (vinylidene fluoride) and poly (vinylidene fluoride-co-hexafluoropropylene), ether-based polymers such as poly (ethylene oxide) and cross-linked products, and poly (acrylonitrile) are used. it can. In particular, it is desirable to use a fluorine-based polymer from the viewpoint of redox stability. By containing an electrolyte salt, ionic conductivity is imparted.

Any electrolyte salt used in the above-described gel electrolyte layer 14 can be used as long as it is used in this type of battery. For example, LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiB (C ₆ H ₅ ) ₄ , LiCH ₃ SO ₃ , LiCF ₃ SO ₃ , LiCl, LiBr, LiN (CF ₃ SO ₂ ) _2, etc. is there.

<Separator>
The separator is for preventing a short circuit between the positive electrode 11 and the negative electrode 12, holding an electrolyte, and the like. As this separator, for example, a polyolefin microporous film such as polyethylene or polypropylene can be used.

  Next, a method for manufacturing a nonaqueous electrolyte secondary battery according to an embodiment of the present invention will be described.

<Positive electrode fabrication process>
First, for example, a positive electrode active material, a binder, a conductive agent, and poly (oxyethylene) or poly (oxypropylene) are mixed to prepare a positive electrode mixture. Then, this positive electrode mixture is dispersed in a solvent to form a slurry. Note that a ball mill, a sand mill, a biaxial kneader, or the like may be used as necessary.

  Next, the slurry-like positive electrode mixture is uniformly applied to both surfaces of the belt-like positive electrode current collector 11a. The coating apparatus is not particularly limited, and for example, slide coating, extrusion type die coating, reverse roll, gravure, knife coater, kiss coater, micro gravure, rod coater, blade coater and the like can be used.

  Next, after drying the positive electrode mixture applied on the positive electrode current collector 11a, the positive electrode mixture layer 11b is formed by compression molding using a roll press or the like. The drying apparatus is not particularly limited, and for example, standing drying, blower dryer, hot air dryer, infrared heater, far infrared heater, and the like can be used.

<Negative electrode fabrication process>
Next, for example, a negative electrode active material and a binder are mixed to prepare a negative electrode mixture. This negative electrode mixture is dispersed in a solvent to form a slurry. Next, the slurry-like negative electrode mixture is uniformly applied to both surfaces of the negative electrode current collector 12a, dried, and then compression molded by a roll press or the like to form the negative electrode mixture layer 12b. In addition, as a coating device and a drying device, the same thing as the case where the above-mentioned positive electrode 11 is produced can be used.

<Electrolyte production process>
Next, an organic solvent and an electrolyte salt are mixed to prepare a plasticizer, and the matrix polymer is dissolved in the plasticizer. And this is uniformly apply | coated and impregnated on the positive mix layer 11b formed in both surfaces of the positive electrode collector 11a, and the negative mix layer 12b formed in both surfaces of the negative electrode collector 12a. Thereafter, for example, the organic solvent is vaporized and removed by leaving it at room temperature for a predetermined time.

<Winding process>
Next, the positive electrode 11 and the negative electrode 12 having the gel electrolyte layer 14 formed on both surfaces, and the separator 13 are sequentially laminated in the order of, for example, the negative electrode 12, the separator 13, the positive electrode 11, and the separator 13. The wound electrode element 1 is produced by winding the core around the core and winding it many times in the longitudinal direction.

<Sealing process>
Next, as shown in FIG. 1, the wound electrode element 1 is housed in an exterior material 2, and the surroundings are thermally welded and vacuum packaged. Through the above steps, a nonaqueous electrolyte secondary battery according to one embodiment of the present invention is manufactured.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples.

Example 1
<Synthesis of positive electrode active material>
Lithium cobalt oxide (positive electrode active material) was prepared by granulating, classifying, and firing lithium cobalt oxide. The positive electrode active material was a particle aggregate having an aspect ratio of 1.1, a 20-fold TAP density of 2.62 g / cm ³ , a 300-fold TAP density of 2.68 g / cm ³ , and a TAP density ratio of 0.98. The TAP density was measured using a powder weight loss measuring instrument (tapping type, manufactured by Tsutsui Rika Kikai Co., Ltd.) according to the measurement method standardized in JISK1201-1. Specifically, a sample is put into a 100 ml cylinder for measuring tap density, and the weight is measured. Then, 20 times tap density is tapped 20 times, 300 times tap density is tapped 300 times, and the volume and sample after tapping. Was used to calculate the tap density.

  As for the aspect ratio, a particle image was photographed with an SEM (Scanning Electron Microscope), and several tens of images were randomly selected from the image, and the major axis and the minor axis were measured with a ruler. And the histogram was produced from this result and the value of accumulation 80% was calculated | required.

<Positive electrode fabrication process>
A mixture of 90% by weight of the above LiCoO ₂ powder (positive electrode active material), 5% by weight of acetylene black (conductive agent), and 5% by weight of polyvinylidene fluoride (binder) was prepared.

Next, this positive electrode mixture was dispersed in N-methyl-2-pyrrolidone to form a slurry. And after apply | coating this uniformly on both surfaces of the aluminum foil 11a which is 20 micrometers in thickness and becomes a strip | belt shape as a positive electrode electrical power collector, it is dried at 140 degreeC more than melting | fusing point of a polyethylene oxide, and 200 kgf / A belt-like positive electrode was produced by compression molding at a pressure of cm ² (19.6 × 10 ⁶ Pa). Here, the volume density was calculated by measuring the weight and thickness of a sample obtained by punching a part of the positive electrode. As a result, the volume density was 3.55 g / cm ³ .

<Negative electrode fabrication process>
First, 90% by weight of pulverized artificial graphite (negative electrode active material) and 10% by weight of polyvinylidene fluoride as a binder were mixed to prepare a negative electrode mixture. Next, this negative electrode mixture was dispersed in N-methyl-2-pyrrolidone to form a slurry. Next, this was 20 micrometers in thickness used as a negative electrode electrical power collector, and it was made to dry after apply | coating uniformly on both surfaces of the strip-shaped copper foil 12a. And the strip-shaped negative electrode was produced by compression molding with a roll press machine.

<Production process of gel electrolyte>
A polyvinylidene fluoride copolymerized with 6.9% of hexafluoropropylene, a non-aqueous electrolyte, and dimethyl carbonate (DMC) as a diluent solvent are mixed, stirred, and dissolved to obtain a sol electrolyte solution. It was. This mixing ratio was a weight ratio of polyvinylidene fluoride: non-aqueous electrolyte: DMC = 1: 6: 12. As the non-aqueous electrolyte, one prepared by mixing ethylene carbonate (EC) and propylene carbonate (PC) at a weight ratio of 6: 4 and dissolving 0.7 mol / kg of LiPF ₆ was used. Next, the obtained sol-form electrolyte solution was uniformly applied on both the positive electrode and the negative electrode. Then, it was made to dry at 50 degreeC for 3 minute (s), the solvent was removed, and the gel electrolyte layer 14 was formed on both surfaces of the positive electrode and the negative electrode.

<Winding process>
Next, a strip-shaped negative electrode and a strip-shaped positive electrode on which the gel electrolyte layer 14 is formed as described above, and a microporous polyethylene film having a thickness of 12 μm are laminated in the order of the negative electrode, the separator, the positive electrode, and the separator. From this, the laminate was wound around a flat plate core and wound many times to produce a wound electrode element.

<Sealing process>
Finally, the wound electrode element produced in this way was housed in an aluminum laminate film in which an aluminum foil was sandwiched between polyolefin films and vacuum packaged. The aluminum laminate sheet type non-aqueous electrolyte secondary battery was produced through the above steps.

Example 2
By changing the synthesis conditions of the lithium cobalt composite oxide (positive electrode active material), the aspect ratio is 1.2, the 20-fold TAP density is 2.42 g / cm ³ , the 300-fold TAP density is 2.63 g / cm ³ , and the TAP density ratio is 0 A positive electrode was produced in the same manner as in Example 1 except that a lithium cobalt composite oxide composed of .92 particle aggregates was produced. Here, when the volume density was calculated by the same method as in Example 1, the volume density was 3.51 g / cm ³ . All subsequent steps were performed in the same manner as in Example 1, and an aluminum laminate sheet type non-aqueous electrolyte secondary battery having the same thickness as in Example 1 was produced.

Example 3
By changing the synthesis conditions of the lithium cobalt composite oxide (positive electrode active material), the aspect ratio 1.3, 20 times TAP density 2.37 g / cm ³ , 300 times TAP density 2.58 g / cm ³ , TAP density ratio 0 A positive electrode was produced in the same manner as in Example 1 except that a lithium cobalt composite oxide composed of .92 was produced. Here, when the volume density was calculated by the same method as in Example 1, the volume density was 3.47 g / cm ³ . All subsequent steps were performed in the same manner as in Example 1, and an aluminum laminate sheet type non-aqueous electrolyte secondary battery having the same thickness as in Example 1 was produced.

Comparative Example 1
By changing the synthesis conditions of the lithium cobalt composite oxide (positive electrode active material), an aspect ratio of 1.5, 20 times TAP density 2.14 g / cm ³ , 300 times TAP density 2.52 g / cm ³ , TAP density ratio 0 A positive electrode was produced in the same manner as in Example 1 except that a lithium cobalt composite oxide comprising a particle aggregate of .85 was produced. Here, when the volume density was calculated by the same method as in Example 1, the volume density was 3.41 g / cm ³ . All subsequent steps were performed in the same manner as in Example 1, and an aluminum laminate sheet type non-aqueous electrolyte secondary battery having the same thickness as in Example 1 was produced.

Comparative Example 2
By changing the synthesis conditions of lithium cobalt composite oxide (positive electrode active material), aspect ratio 1.7, 20 times TAP density 2.01 g / cm ³ , 300 times TAP density 2.48 g / cm ³ , TAP density ratio 0 A positive electrode was produced in the same manner as in Example 1 except that the lithium cobalt composite oxide of .81 was produced. Here, when the volume density was calculated by the same method as in Example 1, the volume density was 3.31 g / cm ³ . All subsequent steps were performed in the same manner as in Example 1, and an aluminum laminate sheet type non-aqueous electrolyte secondary battery having the same thickness as in Example 1 was produced.

Comparative Example 3
By changing the synthesis conditions of the lithium cobalt composite oxide (positive electrode active material), an aspect ratio of 2.1, a 20-fold TAP density of 1.89 g / cm ³ , a 300-fold TAP density of 2.31 g / cm ³ , and a TAP density ratio of 0 A positive electrode was produced in the same manner as in Example 1 except that the lithium cobalt composite oxide of .82 was produced. Here, when the volume density was calculated by the same method as in Example 1, the volume density was 3.25 g / cm ³ . All subsequent steps were performed in the same manner as in Example 1, and an aluminum laminate sheet type non-aqueous electrolyte secondary battery having the same thickness as in Example 1 was produced.

Comparative Example 4
By changing the synthesis conditions of the lithium cobalt composite oxide (positive electrode active material), the aspect ratio 2.2, 20 times TAP density 1.89 g / cm ³ , 300 times TAP density 2.04 g / cm ³ , TAP density ratio 0 A positive electrode was produced in the same manner as in Example 1 except that a lithium cobalt composite oxide of .92 was produced. Here, when the volume density was calculated by the same method as in Example 1, the volume density was 3.11 g / cm ³ . All subsequent steps were performed in the same manner as in Example 1, and an aluminum laminate sheet type non-aqueous electrolyte secondary battery having the same thickness as in Example 1 was produced.

<Characteristic evaluation>
The discharge capacities of the example and the comparative example manufactured by the method described above were measured by constant current discharge in an atmosphere of 23 ° C. and 0.2 C.

  Table 1 below summarizes the evaluation results of Examples 1 to 3 and Comparative Examples 1 to 4.

  As shown in Table 1, the positive electrode active materials of Examples 1 to 3 have a smaller aspect ratio than Comparative Examples 1 to 4. When the active material particle diameter is made spherical, the aspect ratio is decreased, and the 20-fold TAP density is increased. Similarly, the 300-times TAP density also increases, but the difference from the 20-times TAP density decreases, so the TAP density ratio decreases.

  Each of Examples 1 to 3 is a positive electrode active material having an aspect ratio in the range of 1 to 1.5 and a TAP density ratio in the range of 0.92 or more. From Comparative Examples 1 to 4), it was found that the filling property was greatly improved.

  In addition, it was found that the batteries of Examples 1 to 3 can obtain a battery capacity of 550 mAh or more which cannot be obtained depending on the batteries having the same shape using the conventional positive electrode active material. This is because when the TAP density is high, the volume density increases, and when the coating area density is the same, the electrode length becomes long and the battery capacity can be increased.

  From the above, the aspect ratio of the positive electrode active material is in the range of 1 to 1.5 at a cumulative 80%, and the ratio of the 20-fold TAP density to the 300-fold TAP density is in the range of 0.92 to 1 It was found that the filling property can be improved, and as a result, the capacity of the nonaqueous electrolyte secondary battery per unit volume can be increased.

  The present invention is not limited to the above-described embodiment of the present invention, and various modifications and applications are possible without departing from the spirit of the present invention.

It is a disassembled perspective view which shows the example of 1 structure of the nonaqueous electrolyte secondary battery by one Embodiment of this invention. It is a disassembled perspective view which shows one structural example of 1 of a wound battery element. It is sectional drawing which shows one structural example of 1 of a wound battery element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rolling-type electrode element 2 ... Exterior material 3, 4 ... Lead 11 ... Positive electrode 11a ... Positive electrode collector 11b ... Negative electrode mixture layer 12 ... Negative electrode 12a. .... Negative electrode current collector 12b ... Negative electrode mixture layer 13 ... Separator 14 ... Gel electrolyte layer

Claims (2)

A positive electrode active material capable of doping and dedoping lithium,
The aspect ratio of the positive electrode active material is in the range of 1 to 1.5 at a cumulative 80%, and
When the 20-fold TAP density and the 300-fold TAP density of the positive electrode active material are measured, the ratio of the 20-fold TAP density to the 300-fold TAP density is in the range of 0.92 to 1 inclusive. Positive electrode active material. A non-aqueous electrolyte secondary battery using a positive electrode active material capable of doping and dedoping lithium,
The aspect ratio of the positive electrode active material is in the range of 1 to 1.5 at a cumulative 80%, and
When the 20-fold TAP density and the 300-fold TAP density of the positive electrode active material are measured, the ratio of the 20-fold TAP density to the 300-fold TAP density is in the range of 0.92 to 1 inclusive. Non-aqueous electrolyte secondary battery.

Images