JP3178730B2 - Non-aqueous secondary battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-capacity non-aqueous secondary battery using an organic solvent as an electrolyte, and to an electrolyte.

[0002]

2. Description of the Related Art It is known to use a carbonaceous material as a negative electrode of a non-aqueous secondary battery using an organic solvent as an electrolyte. Carbonaceous materials used as electrodes are broadly classified into the following three based on their electrochemical properties. The first is that the distance between carbon network planes represented by graphite is narrow (d ₀₀₂ <0.337 n
m), grown in the direction of lamination of the carbon net surface and the net surface. Such a carbon material is known to form a layered compound by doping both cations and anions between the carbon network planes, and is also considered to be used as a conductive material, an organic synthesis reaction catalyst, and a battery. I have. The use of graphite as a negative electrode of a battery is disclosed in Japanese Patent Application Laid-Open Nos. 57-208079, 58-192266, and 59-192266.
No. 143280, JP-A-60-54181,
JP-A-60-182670, JP-A-60-221
No. 973, JP-A-61-7567, JP-A-1
No. 3,11,565. Organic solvents that can be used in these patents include propylene carbonate (hereinafter abbreviated as PC), tetrahydrofuran (hereinafter abbreviated as THF), and gamma-butyrolactone (hereinafter γ-B).
L), 1,2-dimethoxyethane (hereinafter DME)
), Sulfolane and the like. In the embodiment, LiClO ₄ or LiBF ₄ is used, and PC or THF is used as a representative solvent. Although there is a description that a mixed solvent may be used, there is no description that performance is particularly improved when a mixed solvent is used. An example using a mixed solvent is only PC / DME disclosed in JP-A-57-208079.

However, when charging and discharging were attempted with graphite using LiClO ₄ or LiBF ₄ as an electrolyte and PC as a solvent, charging and discharging were almost impossible. LiBF ₄ is used as an electrolyte, and a mixed solvent of PC / DME is used.
When charging and discharging were attempted using graphite as an electrode, it was found that although charging and discharging were possible, the current efficiency was extremely low and was not practical. When doping lithium as a cation, graphite has a high utilization factor (lithium occlusion amount per carbon) of 16.7%, but when it is used as a negative electrode of a battery, it becomes electrochemically effective as described above. Cannot absorb and release lithium.
This is described in Journal of Electrochemical Society (J. Electrochem. Soc.) Vol. 117, p. 222 (1970), and
As described in Comparative Example 1 of Japanese Patent No. 2555, a layered compound in which lithium ions are occluded in graphite has a high reactivity to an organic solvent, and the reaction with an electrolytic solution is prioritized rather than acting as an electrode. The utility value is low.

The second group has a very large surface area (S _A > 100 m ² / g) typified by activated carbon and a large spacing between carbon network planes (d ₀₀₂ > 0.337 nm).
This type has a large amount of lithium absorbed per carbon due to a large amount of surface adsorption, but has low current efficiency and low cycleability. In the third group, the carbon nets are growing to some extent, but the distance between the carbon nets is wider than in the first group (d ₀₀₂
> 0.337 nm). Although this group exhibits various electrochemical properties depending on its structure, unlike the first group, it can occlude lithium almost without reacting with the electrolyte. However, its utilization rate (the amount of lithium stored per carbon) is smaller than that of the first group.

On the other hand, examples in which graphite is used as a negative electrode are disclosed in US Pat. No. 4,423,125 and Journal of Electrochemical Society (J. Elec.).
trochem. Soc. 137, 2009 (1990); U.S. Pat.
In 125, dioxolan is used as an electrolytic solution. Dioxolane is chemically unstable, and at 3.5V or more electrochemically, polymerization of the electrolytic solution occurs, so that a high-voltage active material cannot be used for the positive electrode, which is inconvenient. Journal of Electrochemical Society (J.El
electrochem. Soc. ) Volume 137, 2009
Page (1990) describes electrochemical lithium intercalation using graphite / petroleum coke as electrodes and PC / EC as electrolyte. In petroleum coke, the side reactions that occur at the time of the first charge depend on the surface area, whereas graphite has side reactions that do not depend on the surface area in addition to the side reactions that depend on the surface area during the first charge. Has been described. When a battery is assembled in such a system, a large number of positive electrodes are required because the initial current efficiency is low, and it is difficult to increase the capacity because the utilization rate of the positive electrode as a battery per active material cannot be increased. . For this reason, in order to increase the capacity, both the positive electrode and the negative electrode are charged (the lithium is occluded in the negative electrode carbon,
In some cases, the positive electrode is assembled in a state where the site for receiving lithium is empty), but the charged state of the electrode is extremely reactive and causes safety problems or inactivity. It is not practical because it is necessary to take complicated steps such as assembling the battery under gas. Furthermore, in this report system, it is described that a side reaction occurs continuously after the second cycle and the current efficiency does not become 100%. High current efficiency is especially important for battery cyclability. In order to discharge at a constant capacity when the current efficiency of the negative electrode is low, the positive electrode always needs a charge amount equal to or greater than the discharge capacity, gradually burdening the positive electrode, and eventually causing the positive electrode to become overcharged, resulting in a decrease in capacity. Bring. If the positive electrode is charged at a constant capacity so that the positive electrode is not overcharged,
Since the current efficiency is low, the capacity is reduced by repeating the cycle.

In any case, in order to obtain a secondary battery having high capacity and good cycle characteristics, what is required for the negative electrode is that the electrode is stable at the time of assembly, the current efficiency is high, and the utilization factor is high. In the conventional electrolyte system, the first group of carbonaceous materials reacts with the electrolyte, and the second group has a low current efficiency, so the utility value is low. However, this also has a utilization factor (the amount of lithium absorbed per carbon atom) of about 10%, and a negative electrode material having a higher utilization factor and a higher current efficiency has been desired in order to increase the capacity of the battery.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a negative electrode combined with a specific organic solvent electrolyte having a high utilization factor and a high current efficiency for increasing the capacity of a secondary battery. It is assumed that.

[0008]

Means for Solving the Problems In order to solve the above problems, the present inventors have intensively studied a combination of a carbonaceous material used for a negative electrode and an organic solvent electrolyte. Can be doped, but if it is used as a negative electrode of a battery, the reaction with the electrolytic solution has priority and cannot be charged and discharged effectively. Graphite is unexpectedly charged and discharged by using an electrolytic solution mainly composed of γ-BL. The inventors have found that the capacity of the battery can be charged and discharged, and that the current efficiency is high. Thus, the present invention has been completed. That is, the present invention provides (1) a non-aqueous secondary battery comprising a chargeable / dischargeable positive electrode, an organic solvent-based electrolyte, and a negative electrode mainly containing a carbonaceous material as an active material.
In, the carbonaceous material is graphite less than 0.337nm is plane spacing d ₀₀₂ of the carbon net plane of the negative electrode active material (however, beep
And (002) plane spacing is 3.45 ° or less,
And the thickness of the crystallite in the c-axis direction is 300 mm or more.
Sofezu spherules contain excluded) to and non-aqueous secondary battery of organic electrolyte solution γ- butyrolactone, characterized in that it contains more than 50 volume% (2) the negative electrode, aqueous or oily organic polymer dispersion
The method of coating and drying after dispersing the negative electrode active material in the body
(1) The negative electrode is a prepared negative electrode.
Non-aqueous secondary battery (3) Non-aqueous secondary battery according to (1) or (2), wherein a transition metal chalcogen compound containing lithium is used as a positive electrode (4) Both the positive electrode and the negative electrode are in a discharged state during battery assembly (1) The non-aqueous secondary battery according to the above (1) or (2) or (3). (5) The electrolyte is a mixed organic solvent containing 50% by volume or more of γ-butyrolactone, and ethylene carbonate is used as a second component. Non-aqueous secondary battery according to (1), (2), (3) or (4), containing at least one selected from the group consisting of propylene carbonate and dimethoxyethane (6) The organic solvent-based electrolyte Has 95-butyrolactone.
An object of the present invention is to provide a non-aqueous secondary battery according to the above item (1), (2), (3), (4) or (5), which contains 50 to 50% by volume.

Hereinafter, the present invention will be described in detail. Graphite having a carbon mesh plane spacing d ₀₀₂ of less than 0.337 nm as referred to in the present invention refers to a carbonaceous material in which laminations of carbon mesh planes are regularly laminated like graphite, for example. The carbonaceous material has various structures depending on its starting material and its processing (manufacturing) method, but in each case, the high-temperature treatment reduces the plane distance d ₀₀₂ between its carbon mesh planes and the lamination thickness Lc of the carbon mesh plane becomes Graphite tends to be large, with graphite having the smallest interplanar spacing d ₀₀₂ = 0.3354 nm. The decrease in d ₀₀₂ and the increase in Lc differ greatly depending on the carbonaceous material, and the graphitizable carbon which is easily graphitized by high-temperature treatment (up to 3000 ° C.) and the graphitization hardly progress (d ₀₀₂ is hardly reduced) are difficult. Classified as graphitized carbon. When the carbonaceous material is graphitized, d
_In addition to Lc, the density, surface area, electric resistance, etc., also vary greatly, but interplanar spacing is particularly important for the formation of an interlayer compound.

The carbonaceous material of the present invention has d ₀₀₂ of 0.337.
Those having a diameter of less than nm are particularly effective, and d ₀₀₂ is 0.337.
If it is not less than nm, the current efficiency becomes low and the amount of lithium stored per carbon (utilization rate) becomes low, which is not preferable. Although the current efficiency may be slightly reduced, the negative electrode of the present invention can also be prepared by using the graphite in combination with another carbonaceous material. , Acetylene black, activated carbon, needle coke and the like.

The d ₀₀₂ used in the present invention is 0.337 n
The graphite having a particle size of less than m is not particularly limited as a starting material, but is generally obtained by heat-treating petroleum pitch, coal tar pitch, pyrolytic carbon, needle coke, condensed polycyclic hydrocarbon and the like at 2500 ° C. or higher, more preferably 3000 ° C. or higher. can get. Naturally occurring graphite can also be used in the present invention. The lamination thickness Lc of the carbon netting surface of the graphite used in the present invention is not particularly limited.
c is also an important parameter, preferably 30 nm or more, more preferably 50 nm or more. If it is less than 30 nm, the utilization tends to be low. The surface area is not particularly limited, but if the surface area is large, many side reactions are likely to occur. Therefore, the surface area is preferably 50 m ² / g or less.

The graphite used in the present invention may be in the form of powder, fiber, or the like, and is not particularly limited. However, powder is preferably used because the packing density is easily increased. A powder having a particle size of 0.1 to 50 microns, preferably 1 to 50 microns is suitably used. As the electrolyte of the present invention, γ
-It is essential to contain 50% or more of BL, and 50%
If it is less than 1, the current efficiency becomes low, which is not preferable. This is similar to the case where another solvent is used, since a solvent other than γ-BL is mainly used, a reaction between the graphite containing lithium and the solvent occurs, and a reduction in current efficiency and a reduction in the utilization factor occur. It is thought to occur. On the other hand, in the electrolytic solution of the present invention mainly composed of γ-BL, it is considered that the reaction with the graphite is suppressed, and both the current efficiency and the utilization factor are increased.

The graphite of the present invention is used as an electrode, and γ containing an electrolyte is used.
-BL shows high current efficiency when evaluated unipolarly,
Transition metal chalcogen compounds containing lithium, such as L
In the case of a battery combined with a positive electrode of iCoO _2, the use of the above-mentioned γ-BL resulted in a decrease in current efficiency and poor cyclability. The exact reason for this is unknown, but
By adding a small amount of a second component other than γ-BL, for example, PC which can hardly charge and discharge by itself, high current efficiency and a high utilization factor can be obtained. Examples of the second component having the same effect include PC, EC, DME, and a mixture thereof.

As a positive electrode combined with the negative electrode of the present invention,
Is not particularly limited, but MnO_Two, MoO_Three,
V_TwoO_Five, V₆O₁₃, Fe_TwoO_Three, Fe_ThreeO_Four, Lichiu
Transition metal chalcogen compound, Li_(1-X)Co
O_Two, Li_(1-X)・ NiO_Two, TiS_Two, MoS_Three, F
eS_Two, CuF_Two, NiF_TwoInorganic compounds such as
Carbon, graphite, vapor grown carbon fiber and / or
The crushed material, pitch-based carbon fiber and / or the crushed material
And other carbon materials, polyacetylene, poly-p-phenylene
And the like. Contains no lithium
For the positive electrode, use the negative electrode of the present invention by absorbing lithium.
Or the required amount of metallic lithium for the negative electrode of the present invention.
A battery can be obtained by using it by bonding. Only
However, such batteries are assembled under inert gas during assembly.
And the assembling process becomes complicated. Lichi
Field using transition metal chalcogen compounds containing
When the battery is assembled in a stable discharge state in air for both the positive and negative electrodes
Can be set up, there are few restrictions on processing and assembly, and
There is no danger of overheating or explosion due to short-circuiting of the battery, etc.
Also preferred from above. Such lithium-containing transition metal
As the lucogen compound, for example, Li_(1-X)Co
O_Two, Li_(1-x)NiO_Two, Li_(1-x)Co_(1-y)Ni
_yO_TwoLiMn_TwoO_Four, Li_(1-X)Co_(1-Y)M_YO_Two
(M is a transition metal other than Co and Ni, Al, In, Sn, etc.
Represents).

Although the electrolyte used in the present invention is not particularly limited, LiBF ₄ , LiAsF ₆ , LiPF
₆ , LiClO ₄ , CF ₃ SO ₃ Li, LiI, LiA
lCl ₄ , NaClO ₄ , NaBF ₄ , NaI, (n-
(Bu) ₄ NCLO ₄ , (n-Bu) ₄ NBF ₄ , KPF
_{6 and the} like, among which LiBF ₄ is preferable from the viewpoints of battery performance, safety in handling and toxicity.

Further, when an electrode is formed using the graphite of the present invention, a current collector, a mixture, or the like may be used. Cu, Ni, or the like is used as the current collector, and Teflon, a mixture, or the like is used as the mixture.
Polyethylene, nitrile rubber, polybutadiene, butyl rubber, polystyrene, styrene / butadiene rubber, polysulfide rubber, nitrocellulose, cyanoethylcellulose, and polymers such as acrylonitrile, vinyl fluoride, vinylidene fluoride, and chloroprene are used. Further, as a method of forming the electrode, a method of mixing an electrode active material and an organic polymer, compression molding, a method of dispersing the electrode active material in a solvent solution of the organic polymer, a method of coating and drying, a method of forming an aqueous solution of the organic polymer, Alternatively, a method of dispersing the electrode active material in an oily dispersion, followed by coating and drying is known, but is not particularly limited, but it is not preferable if the distribution of the binder becomes non-uniform. A method in which the electrode active material is dispersed in the combined aqueous or oily dispersion, followed by coating and drying, more preferably a non-fluorinated organic polymer containing 0.5 μm or less particles in the organic polymer.

If necessary, components such as a separator, a terminal and an insulating plate are used as components of the battery.

[0018]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but it should not be construed that the invention is limited thereto. In Examples 1 to 10 and Comparative Examples 1 to 8, lithium metal was used as a counter electrode in order to observe the performance of the negative electrode alone. In this case, the carbonaceous negative electrode is conventionally used as a positive electrode. However, the negative electrode is referred to as a negative electrode here, and the reduction direction is referred to as charging. Is the amount of discharged electricity / the amount of charged electricity, and the utilization factor is the amount of discharged electricity / the amount of electricity per negative electrode active material weight (12 g is 964).
The number is the number of cycles, and the capacity is the amount of discharged electricity / total weight of the positive electrode and the negative electrode. Cycle 10,
Cycle 100 represents the ratio of the discharge capacity to the discharge capacity in the first cycle of the 10th cycle and the 100th cycle, respectively.

[0019]

Example 1 Graphite (KS6, d manufactured by Lonza)
Styrene / butadiene latex (L1571 manufactured by Asahi Kasei Corporation) (solid content 48% by weight) 4.17 with respect to 100 parts by weight of ₀₀₂ = 0.3355 nm, Lc> 100 nm).
Parts by weight, aqueous solution of carboxymethylcellulose (BSH12 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
%) 130 parts by weight of water and 30 parts by weight of water were added and mixed to obtain a coating liquid. This coating solution was applied and dried using a 10 μm Cu foil as a base material to obtain a negative electrode having a thickness of 100 μm and 93 g / m ² . The negative electrode is peeled off leaving a 1 cm × 1 cm portion,
The working electrode shown in FIG. On the other hand, the counter electrode is SU
An S net with Li metal pressed was used, and a reference electrode was made of lithium metal. The battery shown in FIG. 1 was assembled by using γ-BL obtained by dissolving 1 M LiBF 4 in an electrolytic solution for the above electrodes in an Ar gas atmosphere. This battery was repeatedly charged at a constant voltage of 1 mA to 10 mV and discharged at a constant current of 1 mA to 1 V. The current efficiency in the charge / discharge cycle of this battery is as shown in Table 1.

[0020]

Example 2 EC + γ instead of γ-BL as electrolyte
The same operation as in Example 1 was performed except that -BL (volume ratio 1: 9) was used. Table 1 shows the results.

[0021]

Example 3 EC + γ-BL (volume ratio 1:
The procedure was performed in the same manner as in Example 1 except that 3) was used. Table 1 shows the results.

[0022]

Embodiment 4 PC + γ-BL (volume ratio 2)
7.5: 72.5), except that Example 1 was used. Table 1 shows the results.

[0023]

Comparative Example 1 Example 1 was repeated except that PC was used as the electrolytic solution.
The same was done. Table 1 shows the results.

[0024]

Comparative Example 2 EC + PC (volume ratio: 28: 7) as electrolyte
The procedure was performed in the same manner as in Example 1 except that 2) was used. Table 1 shows the results.

[0025]

Comparative Example 3 EC + PC (volume ratio 50: 5) as electrolyte
0) was performed in the same manner as in Example 1. Table 1 shows the results.

[0026]

Comparative Example 4 PC + γ-BL (volume ratio 7
1:29) was performed in the same manner as in Example 1. Table 1 shows the results.

[0027]

Embodiment 5 As a graphitized negative electrode carbonaceous material, VGCF (vapor-grown carbon fiber d ₀₀₂ = 0.351 nm, Lc = 4.
5 nm) at 2700 ° C., and d ₀₀₂ = 0.
A sample with 336 nm and Lc = 26 nm was obtained. This 10m
g was sandwiched between SUS nets and used as a negative electrode, in the same manner as in Example 1. Table 2 shows the results.

[0028]

Comparative Example 5 The same operation as in Example 5 was carried out except that PC was used as the electrolytic solution. Table 2 shows the results.

[0029]

Example 6 As a negative electrode carbonaceous material, 50 parts by weight of needle coke (d ₀₀₂ = 0.344 nm, Lc = 5.2 nm) pulverized to an average particle size of 10 μm and 50 parts by weight of graphite (KS6) were used. 1M LiCl for electrolyte
The procedure was performed in the same manner as in Example 1 except that O ₄ was used. Table 2 shows the results.

[0030]

Comparative Example 6 Needle coke pulverized to an average particle diameter of 10 μm was used as a negative electrode carbonaceous material, and 1 M was used as an electrolyte.
The operation was performed in the same manner as in Example 1 except that LiClO ₄ was used.
Table 2 shows the results.

[0031]

Comparative Example 7 PC in which 1 M LiClO ₄ was dissolved in an electrolytic solution
Was performed in the same manner as in Example 6 except for using. Table 2 shows the results.

[0032]

Example 7 A particle size of 15 μm (15 μm
95% of graphite (KS1 manufactured by Lonza)
5, d ₀₀₂ = 0.3355 nm, Lc> 100 nm). Table 2 shows the results.

[0033]

Embodiment 8 A negative carbonaceous material having a particle size of 75 μm (75 μm
95% of graphite (KS7 manufactured by Lonza)
5, d ₀₀₂ = 0.3355 nm, Lc> 100 nm). Table 2 shows the results. Examples 9 to 14 and Comparative Examples 8 to 11 show examples of batteries in which a lithium-containing chalcogen compound is combined as a positive electrode.

[0034]

Example 9 100 parts by weight of LiCoO _{2 having a} particle size of 3 μm were mixed with graphite (KS6) 20 as a conductive filler.
100 parts by weight of a 5% polyvinylidene fluoride solution as a binder were added and mixed to obtain a coating liquid. 15 μm
This coating liquid is applied and dried using an Al foil as a base material to a thickness of 12
A positive electrode of 0 μm and 370 g / m ² was obtained. The above positive electrode and the negative electrode (93 g / m ² ) obtained in Example 1 were 1 cm × 1 cm
The battery shown in FIG. 2 was assembled. Γ-BL (electrolyte 1M LiBF ₄ ) was used as the electrolyte. This battery was charged at a constant voltage to 4.2 V at 5 mA, and 2.7 at 5 mA.
The cycle of discharging at a constant current to V was repeated. Table 3 shows the current efficiency in the charge / discharge cycle of this battery.

[0035]

Example 10 EC + γ-BL (volume ratio 1: 9)
The procedure was performed in the same manner as in Example 9 except that 9) was used. Table 3 shows the results.

[0036]

Embodiment 11 EC + γ-BL (volume ratio 1:
The procedure was performed in the same manner as in Example 9 except that 9) was used. Table 3 shows the results.

[0037]

Example 12 EC + γ-BL (volume ratio 1:
The procedure was performed in the same manner as in Example 9 except that 3) was used. Table 3 shows the results.

[0038]

Comparative Example 8 EC + γ-BL (volume ratio 3: 1) was used as the electrolyte.
Was performed in the same manner as in Example 11 except that Table 3 shows the results
Shown in

[0039]

Comparative Example 9 The same operation as in Example 9 was carried out except that PC was used as the electrolytic solution. Table 3 shows the results. From Table 3, it is clear that the current efficiency is low when γ-BL alone is used, but the current efficiency is high in a system mainly composed of γ-BL due to the effect of the added component. Next, in order to compare the capacity and cycleability of the negative electrode, the comparison was performed by changing the basis weight ratio of the positive electrode and the negative electrode according to the current efficiency.

[0040]

Embodiment 13 Positive electrode 400 g / m ² , negative electrode 93 g / m ²
Was performed in the same manner as in Example 10 except for using. Table 4 shows the results.

[0041]

Example 14 Positive electrode: 360 g / m ² , Negative electrode: 93 g / m ²
The procedure was performed in the same manner as in Example 11 except for using. Table 4 shows the results.

[0042]

Embodiment 15 Positive electrode 350 g / m ² , negative electrode 93 g / m ²
Was performed in the same manner as in Example 12 except for using. Table 4 shows the results.

[0043]

Comparative Example 10 Positive electrode 700 g / m ² , Negative electrode 93 g / m ²
Was performed in the same manner as in Comparative Example 8 except that was used. Table 4 shows the results.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

According to the present invention, the negative electrode of the present invention (the spacing _d002 between carbon net faces)
Is a carbonaceous material containing less than 0.337 nm of graphite
And a combination of an electrolyte containing 50% by volume or more of γ-butyrolactone and various kinds of positive electrodes have high current efficiency,
In addition, a non-aqueous secondary battery having a large capacity can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a configuration example of a battery of the present invention.

FIG. 2 is a cross-sectional view of a configuration example of the battery of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Working electrode (carbon negative electrode) 2 Counter electrode (lithium metal) 3 Reference electrode (lithium metal) 4 Electrolyte 5 Glass container 6 Ar gas 7 Positive electrode 8 Negative electrode 9 Current collecting rod 10 Current collecting rod 11 SUS net 12 SUS net 13 External electrode terminal 14 External electrode terminal 15 Battery case 16 Separator

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01M 4/58 H01M 4/02-4/04 H01M 10/40

Claims (2)

(57) [Claims] 1. A rechargeable positive electrode and organic solvent-based non-aqueous secondary battery comprising the electrolyte and a carbonaceous material from the negative electrode mainly the active material, the carbonaceous material of the negative electrode active material surface of the carbon net plane Graphite with a spacing d ₀₀₂ of less than 0.337 nm ( but
And (002) plane spacing is 3.45 °
Or less, and the thickness of the crystallite in the c-axis direction is 300 ° or more.
A non-aqueous secondary battery characterized in that the organic solvent-based electrolyte contains 50% by volume or more of γ-butyrolactone ( excluding carbonized mesophase spheres) . 2. The method according to claim 1, wherein the negative electrode is an aqueous solution of an organic polymer.
After the negative electrode active material is dispersed in the oily dispersion, coating and drying are performed.
The negative electrode produced by a method according to claim
2. The non-aqueous secondary battery according to 1.