Lithium iron phosphate ion battery and method for manufacturing lithium iron phosphate ion battery

Abstract

The discharge energy of the lithium iron phosphate ion battery is improved. The method of manufacturing a lithium iron phosphate ion battery includes: a step of forming a positive electrode including lithium, iron, phosphorus, and amorphous carbon; a step of forming a negative electrode including graphite and amorphous carbon; and a step of placing the positive electrode, the negative electrode, and the predetermined electrolyte in a predetermined container and sealing the container. At least one of the amorphous carbon in the positive electrode or the amorphous carbon in the negative electrode has 10 wt% or less of fullerene or carbon nanotubes.

Description

Technical Field

[0001] The present invention relates to a lithium iron phosphate battery and a method for manufacturing the lithium iron phosphate battery. Background Art

[0002] Lithium-ion batteries are known for their high energy density, rapid charge and discharge capabilities, and long life expectancy. It is well known that lithium-ion batteries can be constructed using a variety of materials, such as ternary lithium-ion batteries using nickel, manganese, and cobalt as positive electrode materials, and lithium iron phosphate lithium-ion batteries using lithium iron phosphate (LFP: LiFePO4) as a positive electrode material (for example, see Patent Document 1).

[0003] Existing technology

[0004] Patent Literature

[0005] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2017-212045 Summary of the Invention

[0006] Problems to be solved by the present invention

[0007] Unlike ternary lithium-ion batteries, iron phosphate lithium-ion batteries can be constructed without using rare metals such as cobalt, thereby reducing manufacturing costs. However, compared with ternary lithium-ion batteries, iron phosphate lithium-ion batteries have the disadvantage of lower discharge energy.

[0008] The present invention has been made in view of these points, and an object thereof is to enhance the discharge energy of a lithium iron phosphate lithium ion battery.

[0009] Means used to solve problems

[0010] A first aspect of the present invention provides a method for manufacturing a lithium iron phosphate (LiFePO4) ion battery, comprising the steps of: forming a positive electrode comprising lithium, iron, phosphorus, and amorphous carbon; forming a negative electrode comprising graphite and amorphous carbon; and loading the positive electrode, the negative electrode, and a predetermined electrolyte into a predetermined container and hermetically sealing the container, wherein at least one of the amorphous carbon in the positive electrode or the amorphous carbon in the negative electrode contains 10 wt % or less of fullerenes or carbon nanotubes.

[0011] Forming the positive electrode may include applying a positive electrode slurry including a positive electrode material including lithium iron phosphate and amorphous carbon to a substrate, and drying the positive electrode slurry to form the positive electrode, wherein the amorphous carbon in the positive electrode material includes 10 wt % or less of fullerene or carbon nanotube.

[0012] Forming the negative electrode may include applying a negative electrode slurry including a negative electrode material including graphite and amorphous carbon to a substrate and drying the negative electrode slurry to form the negative electrode, wherein the amorphous carbon in the negative electrode material includes 10 wt % or less of fullerene or carbon nanotube.

[0013] At least one of the amorphous carbon in the positive electrode or the amorphous carbon in the negative electrode may contain 5 wt % or less of fullerene or carbon nanotube.

[0014] Forming the positive electrode may include applying a positive electrode slurry including a positive electrode material including lithium iron phosphate and amorphous carbon to a substrate, and drying the positive electrode slurry to form the positive electrode, wherein the amorphous carbon in the positive electrode material includes 5 wt % or less of fullerene or carbon nanotube.

[0015] Forming the negative electrode may include applying a negative electrode slurry including a negative electrode material including graphite and amorphous carbon to a substrate and drying the negative electrode slurry to form the negative electrode, wherein the amorphous carbon in the negative electrode material includes 5 wt % or less of fullerene or carbon nanotube.

[0016] A second aspect of the present invention provides a lithium iron phosphate battery comprising: a positive electrode comprising lithium, iron, phosphorus and amorphous carbon; a negative electrode comprising graphite and amorphous carbon; and an electrolyte, wherein at least one of the amorphous carbon in the positive electrode or the amorphous carbon in the negative electrode contains 10 wt % or less of fullerenes or carbon nanotubes.

[0017] At least one of the amorphous carbon in the positive electrode or the amorphous carbon in the negative electrode may contain 5 wt % or less of fullerene or carbon nanotube.

[0018] Effects of the present invention

[0019] According to the present invention, the effect of improving the discharge energy of a lithium iron phosphate battery can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 An example of a schematic configuration of the lithium iron phosphate battery 10 according to the present embodiment is shown.

[0021] Figure 2 An example of a manufacturing flow of the lithium iron phosphate battery 10 according to the present embodiment is shown.

[0022] Figure 3 A configuration example of the lithium iron phosphate battery 10 according to the present embodiment is shown.

[0023] Figure 4 An example of an assembly flow of the lithium iron phosphate battery 10 according to the present embodiment is shown.

[0024] Figure 5 The results of high performance liquid chromatography analysis of the conductive additive in the lithium iron phosphate lithium ion battery 10 according to the present embodiment are shown.

[0025] Figure 6A first example of the charge and discharge characteristics of the lithium iron phosphate battery 10 according to the present embodiment is shown.

[0026] Figure 7 A second example of the charge and discharge characteristics of the lithium iron phosphate battery 10 according to the present embodiment is shown.

[0027] Figure 8 An example of the charge and discharge cycle characteristics of the lithium iron phosphate battery 10 according to the present embodiment is shown.

[0028] Figure 9 An example of charge and discharge characteristics of the second comparative example is shown.

[0029] Figure 10 An example of the charge and discharge cycle characteristics of the second comparative example is shown. DETAILED DESCRIPTION

[0030] <Schematic Configuration of Lithium Iron Phosphate Battery 10>

[0031] Figure 1 The schematic configuration example of the lithium iron phosphate battery 10 according to the present embodiment is shown. The lithium iron phosphate battery 10 is a rechargeable secondary battery. The lithium iron phosphate battery 10 includes a positive electrode (cathode) 20, a negative electrode (anode) 30, a separator 40, an electrolyte 50, and a housing 60.

[0032] Positive electrode 20 includes lithium, iron, phosphorus, and amorphous carbon. The active material of positive electrode 20 is lithium iron phosphate. For example, positive electrode 20 is formed from lithium iron phosphate, amorphous carbon, and a binder such as PVDF (polyvinylidene fluoride) as the positive electrode material. The amorphous carbon is a conductive additive such as Ketjen Black or acetylene black. Conductive additives are materials used to reduce the resistance of electrodes used in lithium-ion batteries.

[0033] The negative electrode 30 includes graphite and amorphous carbon. The active material of the negative electrode 30 is graphite. For example, the negative electrode 30 is an electrode formed of amorphous carbon, a thickener such as CMC (carboxymethyl cellulose), or a binder such as SBR (styrene-butadiene rubber) as the negative electrode material.

[0034] The separator 40 allows lithium ions to move between the positive electrode 20 and the negative electrode 30 while separating the positive electrode 20 and the negative electrode 30. For example, the separator 40 is a film having a thickness of about several tens of micrometers and a plurality of through-pores of 1 micrometer or less. For example, the separator 40 is formed of polyethylene, polypropylene, etc.

[0035] The electrolyte 50 dissociates lithium into cations and anions, allowing ion migration. The electrolyte 50 is a solvent, solution, gel-like substance, or the like. For example, the electrolyte 50 is an organic electrolyte solution in which approximately 1 mol of a lithium salt (such as LiPF6, LiBF4, or LiClO4) is dissolved in an organic solvent. Examples of organic solvent materials include ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC).

[0036] The housing 60 houses the positive electrode 20, the negative electrode 30, the separator 40, and the electrolyte 50. The housing 60 is preferably a container that hermetically seals the positive electrode 20, the negative electrode 30, the separator 40, and the electrolyte 50. The housing 60 includes a positive electrode terminal 61 electrically connected to the positive electrode 20 and a negative electrode terminal 62 electrically connected to the negative electrode 30.

[0037] When a power source is connected to the positive electrode terminal 61 and the negative electrode terminal 62, the lithium iron phosphate battery 10 is charged. When the lithium iron phosphate battery 10 is charged, electrons migrate from the positive electrode 20 to the negative electrode 30, and lithium ions migrate from the positive electrode 20 through the electrolyte 50 and accumulate in the negative electrode 30, thereby generating a potential difference between the positive electrode 20 and the negative electrode 30.

[0038] On the other hand, when a discharge circuit such as a load is connected to the positive electrode terminal 61 and the negative electrode terminal 62, the lithium iron phosphate battery 10 is discharged. When the lithium iron phosphate battery 10 is discharged, electrons flow from the negative electrode 30 to the positive electrode 20 through the discharge circuit, and lithium ions accumulated in the negative electrode 30 migrate to the positive electrode 20 through the electrolyte 50 and combine with electrons in the positive electrode 20 to be reduced to lithium oxide.

[0039] In the lithium iron phosphate lithium ion battery 10 according to this embodiment, discharge energy is improved by including fullerenes or carbon nanotubes in at least one of the positive electrode 20 or the negative electrode 30. For example, the lithium iron phosphate lithium ion battery 10 includes 5 wt% or less of fullerenes or carbon nanotubes in at least one of the amorphous carbon in the positive electrode 20 or the amorphous carbon in the negative electrode 30. Here, the fullerene may have a C60 structure, or alternatively, a C70 structure. The fullerene may also be a mixture of a fullerene having a C60 structure and a fullerene having a C70 structure.

[0040] In this way, the inventors discovered that when the conductive additive includes only an appropriate amount of fullerenes or carbon nanotubes, the electrode resistance is further reduced. In other words, the inventors discovered that when the conductive additive includes an appropriate amount of fullerenes or carbon nanotubes, the discharge energy of the lithium iron phosphate lithium ion battery 10 is increased.

[0041] For example, the amount of fullerenes or carbon nanotubes relative to the amorphous carbon in the electrode is 1 wt% or more and 5 wt% or less. The amount of fullerenes or carbon nanotubes relative to the graphite in the electrode can be 2 wt% or more and 4 wt% or less, or 2.5 wt% or more and 3.5 wt% or less. Next, a method for manufacturing such a lithium iron phosphate battery 10 will be described.

[0042] <Manufacturing Process of Lithium Iron Phosphate Battery 10>

[0043] Figure 2 An example of a manufacturing process of the lithium iron phosphate battery 10 according to the present embodiment is shown. In the present embodiment, a button battery is described as an example of the lithium iron phosphate battery 10.

[0044] First, the positive electrode 20 and the negative electrode 30 are formed. For example, the positive electrode 20 and the negative electrode 30 are formed separately. The positive electrode 20 and the negative electrode 30 can be formed at the same time, or they can be formed at different times. For example, the negative electrode 30 can be formed after the positive electrode 20, or alternatively, the positive electrode 20 can be formed after the negative electrode 30. Figure 2 An example is shown in which the positive electrode 20 and the negative electrode 30 are formed simultaneously in terms of time.

[0045] First, the formation of the positive electrode 20 including lithium, iron, phosphorus, and amorphous carbon will be described. As an example of the film composition of the positive electrode 20, the weight ratio of lithium iron phosphate, amorphous carbon, and PVDF is 91:4:5. The amorphous carbon in the positive electrode material contains 5 wt% or less of fullerenes or carbon nanotubes. In this embodiment, it is assumed that 3 wt% of fullerenes are added to the amorphous carbon.

[0046] More specifically, first, an LFP cathode material composed of lithium, iron, and phosphorus is vacuum-dried (S81). For example, the LFP cathode material is placed in a vacuum chamber, etc., and dried by evacuating the chamber with a vacuum pump and then maintaining the material at a temperature of approximately 200°C for approximately 5 hours.

[0047] Next, a positive electrode slurry is formed by adding the dried LFP positive electrode material and amorphous carbon containing fullerenes to a solution (in which PVDF is dissolved in a solvent such as N-methylpyrrolidone (NMP) and a dispersant is added to the solution) and stirring the resulting mixture (S82). For example, the amount of dispersant is approximately 2 wt% relative to the positive electrode material. NMP is then added to the positive electrode slurry and stirred until it reaches a predetermined concentration. For example, the predetermined concentration is 45 wt% solids content.

[0048] Next, the positive electrode 20 is formed by applying a positive electrode slurry containing a positive electrode material including lithium iron phosphate and amorphous carbon to a substrate and drying the positive electrode slurry (S83). For example, the substrate is an aluminum foil with a surface coated with graphite. For example, the graphite film thickness is approximately 1 μm, and the aluminum foil thickness is approximately 12 μm. Preferably, only a predetermined amount of the positive electrode slurry is applied to the substrate to form a predetermined dry film thickness. For example, the predetermined dry film thickness is approximately 80 μm. The positive electrode slurry is preferably applied using a slot coater or the like.

[0049] For example, the applied positive electrode slurry is dried in air at a temperature of approximately 110°C for approximately 15 minutes to form a positive electrode material coating having a dry film thickness. The positive electrode material coating is then pressed and formed to a predetermined thickness. For example, the predetermined thickness is approximately 70 μm. The positive electrode 20 is formed by cutting the positive electrode material coating having the predetermined thickness into a predetermined shape.

[0050] Next, the formation of the negative electrode 30 comprising graphite and amorphous carbon will be described. As an example of the film composition of the negative electrode 30, the weight ratio of graphite, amorphous carbon, CMC, and SBR is 93.5:2.5:2:2. The amorphous carbon is Ketjen Black, acetylene black, or the like. The amorphous carbon in the negative electrode material contains 5 wt% or less of fullerenes or carbon nanotubes. In this embodiment, it is assumed that 3 wt% of fullerenes are added to the amorphous carbon.

[0051] More specifically, first, a negative electrode slurry is formed (S84). For example, a predetermined amount of graphite powder and a predetermined amount of amorphous carbon are added to an aqueous solution of CMC, and the resulting mixture is stirred. A predetermined amount of SBR solution is then added to the resulting mixture and stirred to form the negative electrode slurry. As an example, the aqueous CMC solution contains 2 wt% CMC. Distilled water is then added to the negative electrode slurry and the resulting mixture is stirred until the negative electrode slurry reaches a predetermined concentration. For example, the predetermined concentration is 40 wt% solids content.

[0052] Next, the negative electrode 30 is formed by applying a negative electrode slurry containing a negative electrode material including graphite and amorphous carbon to a substrate and drying the negative electrode slurry (S85). For example, the substrate is a copper foil coated with carbon nanotubes. For example, the carbon nanotube film thickness is approximately 1 μm, and the copper foil thickness is approximately 6 μm. Preferably, only a predetermined amount of negative electrode slurry is applied to the substrate to form a predetermined dry film thickness. For example, the predetermined dry film thickness is approximately 80 μm. The negative electrode slurry is preferably applied using a slot coater or the like.

[0053] For example, the applied negative electrode slurry is dried in air at approximately 80°C for approximately 10 minutes to form a negative electrode material coating having a dry film thickness. The negative electrode material coating is then pressed and formed to a predetermined thickness. For example, the predetermined thickness is approximately 60 μm. The negative electrode 30 is formed by cutting the negative electrode material coating having the predetermined thickness into a predetermined shape.

[0054] After the positive electrode 20 and the negative electrode 30 are formed, the positive electrode 20, the negative electrode 30 and the predetermined electrolyte 50 are placed in a predetermined container, and the container is hermetically sealed to assemble the lithium iron phosphate battery 10 (S86). Thus, the lithium iron phosphate battery 10 can be formed.

[0055] <Configuration Example of Lithium Iron Phosphate Battery 10>

[0056] Figure 3 A configuration example of the lithium iron phosphate battery 10 according to the present embodiment is shown. Figure 4 An example of the assembly process of the lithium iron phosphate battery 10 according to this embodiment is shown. In other words, Figure 3 and Figure 4 It is shown in detail Figure 2 FIG. 5 is a diagram of the operation of S86 for assembling the lithium iron phosphate battery 10 described in FIG.

[0057] The lithium iron phosphate battery 10 further includes a housing 11, a sealing ring 12, a spacer 13, a gasket 14, and a lid 15. The outer casing 60 is formed by assembling the housing 11 and the lid 15. Prior to assembling the lithium iron phosphate battery 10, the positive electrode 20 and the negative electrode 30 are preferably dried using a vacuum chamber or the like. In this case, for example, the positive electrode 20 is dried at approximately 110°C for approximately 8 hours, and the negative electrode 30 is dried at approximately 90°C for approximately 8 hours. It is assumed that the separator 40 has already been cut into a predetermined shape.

[0058] First, the sealing ring 12 is attached to the housing 11 (S91). Next, the positive electrode 20 is placed in the housing 11 (S92). Next, the separator 40 is placed on the positive electrode 20 in the housing 11 (S93). Next, a predetermined amount of electrolyte solution is dripped onto the separator 40 in the housing 11 using a pipette or the like (S94). For example, the electrolyte solution is an organic electrolyte solution in which approximately 1 mol of a lithium salt (LiPF6) is dissolved in a mixture of EC, DMC, and EMC at a weight ratio of 1:1:1. Preferably, the electrolyte solution is dripped so that the positive electrode 20, the negative electrode 30, and the separator 40 are immersed in the electrolyte solution.

[0059] Next, negative electrode 30 is placed on separator 40 containing an electrolyte solution (S95). Next, separator 13 is placed on negative electrode 30 in case 11 (S96). Next, gasket 14 is placed on separator 13 in case 11 (S97). Next, lid 15 is placed on seal ring 12 attached to case 11 (S98). Next, lid 15 is pressed from above, and case 11 and lid 15 are assembled together via seal ring 12 (S99).

[0060] As a result, the lithium iron phosphate battery 10 can be assembled. Preferably, the assembly operations of S91 to S99 are performed in an argon atmosphere or a dry atmosphere having a humidity dew point of -50°C or lower. The characteristics of the lithium iron phosphate battery 10 formed as described above will be described.

[0061] <Example of Characteristics of Lithium Iron Phosphate Battery 10>

[0062] Figure 5 The results of high performance liquid chromatography (HPLC) analysis of the conductive additive (amorphous carbon) in the lithium iron phosphate battery 10 according to the present embodiment are shown. Figure 5 The results of HPLC analysis of a solution obtained by dissolving 2.1 mg of amorphous carbon in 5 ml of o-DCB (o-dichlorobenzene) solvent and filtering the turbid liquid through a 0.2 μm filter are shown. Comparison of the peak area values ​​in the analysis results indicates that the content of fullerene C60 and fullerene C70 in the amorphous carbon is estimated to be approximately 3.5%.

[0063] Figure 6 A first example of the charge and discharge characteristics of the lithium iron phosphate battery 10 according to the present embodiment is shown. Figure 6 Shown by Figures 2 to 4 The charge and discharge characteristics of the lithium iron phosphate battery 10 manufactured by the manufacturing process and assembly process described in Figure 6 In , the horizontal axis represents time, and the vertical axis represents voltage. For comparison, Figure 6 Characteristics of a lithium iron phosphate battery in which fullerenes and carbon nanotubes are not included in amorphous carbon are shown as a “first comparative example.” In other words, the first comparative example is a normal lithium iron phosphate battery.

[0064] exist Figure 6 In the figure, the dotted line indicates the time point after about 12 hours (43200 seconds). Figure 6 Results of charging the lithium iron phosphate battery 10 and the first comparative example from 0 to about 12 hours on the time axis and results of discharging the lithium iron phosphate battery 10 and the first comparative example after about 12 hours have passed are shown. Figure 6The discharge time of the lithium iron phosphate battery 10 according to the present embodiment is shown to be approximately 20% longer than that of the first comparative example. Therefore, it can be seen that the lithium iron phosphate battery 10 can exhibit a discharge energy that is approximately 20% higher than that of a conventional lithium iron phosphate battery.

[0065] <Example of Fullerene or Carbon Nanotube Containing More Than 5 wt%>

[0066] In the lithium iron phosphate lithium ion battery 10 according to the present embodiment described above, an example has been described in which at least one of the positive electrode 20 or the negative electrode 30 contains 5 wt% or less of fullerenes or carbon nanotubes. However, the present embodiment is not limited thereto. The amount of fullerenes or carbon nanotubes relative to the amorphous carbon in the electrode may be greater than 5 wt%. For example, at least one of the amorphous carbon in the positive electrode 20 or the amorphous carbon in the negative electrode 30 may contain 10 wt% or less of fullerenes or carbon nanotubes.

[0067] In this case, for example, the amorphous carbon in the positive electrode material contains 10 wt % or less of fullerenes or carbon nanotubes. Alternatively or additionally, the amorphous carbon in the negative electrode material may contain 10 wt % or less of fullerenes or carbon nanotubes.

[0068] Figure 7 A second example of the charge and discharge characteristics of the lithium iron phosphate battery 10 according to the present embodiment is shown. Figure 7 The method of adding 10 wt% of fullerene to amorphous carbon in a positive electrode material and 10 wt% of fullerene to amorphous carbon in a negative electrode material and using Figures 2 to 4 The charge and discharge characteristics of the lithium iron phosphate battery 10 manufactured using the manufacturing and assembly process described in the embodiment of the present invention are shown in FIG.

[0069] from Figure 7 It can be seen that similar to Figure 6 As a result, the lithium iron phosphate ion battery 10 including 10 wt % of fullerene in the positive electrode 20 and the negative electrode 30 may have a discharge energy that is approximately 20% higher than that of a conventional lithium iron phosphate ion battery.

[0070] Figure 8 An example of the charge and discharge cycle characteristics of the lithium iron phosphate battery 10 according to this embodiment is shown. The charge and discharge cycle characteristics represent the charge and discharge cycle characteristics when the battery is repeatedly charged and discharged. Figure 7 The results obtained by plotting the discharge capacity and charge capacity at the end of each cycle are shown in the figure. Figure 8 It can be seen that the lithium iron phosphate battery 10 fully performs the function of a rechargeable battery.

[0071] Figure 9 and Figure 10The characteristics of the second comparative example are shown. The second comparative example is a lithium iron phosphate battery in which the mixing ratio of fullerene is 100 wt %. In other words, the second comparative example is a lithium iron phosphate battery in which fullerene is used instead of amorphous carbon in both the positive electrode material and the negative electrode material.

[0072] Figure 9 An example of the charge and discharge characteristics of the second comparative example is shown. It can be seen that the second comparative example exhibits a low discharge capacity and an undesirable sharp rise in charge voltage. Figure 10 An example of charge and discharge cycle characteristics of the second comparative example is shown. In the second comparative example, the discharge capacity and the charge capacity are lower than those of the lithium iron phosphate battery 10.

[0073] from Figure 9 and Figure 10 It can be seen that the second comparative example functions more as a capacitor than as a battery. This is likely because the low electrical conductivity (or ionic conductivity) of fullerenes leads to reduced ionic conductivity within the active material and a decrease in battery function. Therefore, it is understood that the discharge energy of the lithium iron phosphate lithium-ion battery 10 can be increased by including an appropriate amount (e.g., 10 wt% or less) of fullerenes or carbon nanotubes in the conductive additive.

[0074] The lithium iron phosphate battery 10 according to this embodiment is described as an example involving the manufacture of a button battery, but the embodiment is not limited thereto. Other structures may be used, and the lithium iron phosphate battery 10 may simply employ the positive electrode 20 and / or the negative electrode 30 in which a predetermined amount of fullerene or carbon nanotubes is included as a conductive additive.

[0075] The present disclosure has been described based on exemplary embodiments. The technical scope of the present disclosure is not limited to the scope described in the above embodiments, and various changes and modifications can be made within the scope of the present disclosure. For example, all or part of the device can be configured with any unit that is functionally or physically dispersed or integrated. In addition, new exemplary embodiments generated by any combination of exemplary embodiments are included in the exemplary embodiments. In addition, the effects of the new exemplary embodiments brought about by the combination also have the effects of the original exemplary embodiments.

[0076] [Explanation of Reference Numerals]

[0077] 10 lithium iron phosphate battery

[0078] 11 Shell

[0079] 12 sealing rings

[0080] 13 spacers

[0081] 14 washers

[0082] 15 covers

[0083] 20 positive electrode

[0084] 30 negative electrode

[0085] 40 diaphragms

[0086] 50 electrolytes

[0087] 60 shell

[0088] 61 positive terminal

[0089] 62 negative terminal

Claims

1. A method for manufacturing a lithium iron phosphate battery, comprising the following steps: forming a positive electrode including lithium, iron, phosphorus, and amorphous carbon; forming a negative electrode comprising graphite and amorphous carbon; and The positive electrode, the negative electrode, and a predetermined electrolyte are loaded into a predetermined container and the container is hermetically sealed, wherein at least one of the amorphous carbon in the positive electrode or the amorphous carbon in the negative electrode contains 10 wt % or less of fullerene or carbon nanotube.

2. The method for manufacturing the lithium iron phosphate battery according to claim 1, wherein: Forming the positive electrode includes: applying a positive electrode slurry containing a positive electrode material including lithium iron phosphate and amorphous carbon to a substrate, and drying the positive electrode slurry to form the positive electrode, and The amorphous carbon in the positive electrode material contains 10 wt % or less of the fullerene or the carbon nanotube.

3. The method for manufacturing the lithium iron phosphate battery according to claim 1 or 2, wherein: Forming the negative electrode includes: applying a negative electrode slurry containing a negative electrode material including graphite and amorphous carbon to a substrate, and drying the negative electrode slurry to form the negative electrode, and The amorphous carbon in the negative electrode material contains 10 wt % or less of the fullerene or the carbon nanotube.

4. The method for manufacturing the lithium iron phosphate battery according to claim 1, wherein: At least one of the amorphous carbon in the positive electrode or the amorphous carbon in the negative electrode contains 5 wt % or less of fullerenes or carbon nanotubes.

5. The method for manufacturing the lithium iron phosphate battery according to claim 4, wherein: Forming the positive electrode includes: applying a positive electrode slurry containing a positive electrode material including lithium iron phosphate and amorphous carbon to a substrate, and drying the positive electrode slurry to form the positive electrode, and The amorphous carbon in the positive electrode material contains 5 wt % or less of the fullerene or the carbon nanotube.

6. The method for manufacturing the lithium iron phosphate battery according to claim 4 or 5, wherein: Forming the negative electrode includes: applying a negative electrode slurry containing a negative electrode material including graphite and amorphous carbon to a substrate, and drying the negative electrode slurry to form the negative electrode, and The amorphous carbon in the negative electrode material contains 5 wt % or less of the fullerene or the carbon nanotube.

7. Lithium iron phosphate batteries, including: a cathode, comprising lithium, iron, phosphorus, and amorphous carbon; anode, including graphite and amorphous carbon; as well as An electrolyte, wherein at least one of the amorphous carbon in the positive electrode or the amorphous carbon in the negative electrode contains 10 wt % or less of fullerenes or carbon nanotubes.

8. The lithium iron phosphate battery according to claim 7, wherein: At least one of the amorphous carbon in the positive electrode or the amorphous carbon in the negative electrode contains 5 wt % or less of fullerenes or carbon nanotubes.

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