JP2002216765A - Positive electrode material, lithium secondary battery and lithium ion secondary battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel lithium secondary battery and a novel lithium ion secondary battery capable of providing high capacity and high energy density, of a long life and superior in repeated charging and discharging characteristics. SOLUTION: This invention relates to positive electrode material composed of oligomer above dimer or two-dimensional polymer of poly(cyano(metal) phthalocyanine) or poly(cyano(metal)pyrazinocyanine), and the lithium secondary battery and lithium ion secondary battery including the same material as a positive electrode member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lithium (ion) secondary battery. More specifically, lithium metal, lithium / aluminum alloy, lithium graphite (hereinafter abbreviated as Li-Gp) or the like is used as an anode, and a lithium hexafluorophosphate organic solvent solution or a film in which the polymer gel is impregnated with a polymer gel is used as an electrolyte. And a material used as a cathode member thereof.

[0002]

2. Description of the Related Art A lithium (ion) secondary battery according to a conventional technique has a configuration of [metal lithium / electrolyte / polyaniline] or [Li · Gp / electrolyte / lithium cobalt oxide], and has an output of 3%. ~ 4.2V, but the battery capacity
The energy density is limited by the low capacity of the cathode member, and the battery capacity is only 150 mAh / g and the energy density is about 550 Wh / kg.

[0003]

SUMMARY OF THE INVENTION In view of the above situation, the present invention provides a novel lithium (ion) capable of obtaining a higher capacity and a higher energy density, having a long life and excellent repetitive charge / discharge characteristics. It is intended to provide a secondary battery.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention relates to a poly-method as defined in claim 1 (formula 1).
Provided is a cathode material comprising a dimer or higher oligomer or a two-dimensional polymer of [cyano (metal) phthalocyanine] or poly [cyano (metal) pyrazinocyanine].

[0005] Claims 2 and 3 are lithium secondary batteries and lithium ion secondary batteries comprising the material described in claim 1 in a cathode member. In addition,
Here, a lithium-ion secondary battery refers to Li
-A material using non-metallic lithium such as Gp.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The cathode material of the present invention comprises a poly [cyano (metal) phthalocyanine] or a poly [cyano (metal) phthalocyanine]
It is composed of a dimer or higher oligomer or a two-dimensional polymer (hereinafter abbreviated as a two-dimensional polymer) of [cyano (metal) pyrazinocyanine].

However, in the above (Chemical Formula 1), M = H ₂ or a transition metal ion of Groups 4 to 12 in the periodic table, M ′ is defined in the same manner as M, and M ′ = M or M ′ ≠ M, X = C or N, X ′ is defined as X, and X ′ =
X or X ′ ≠ X, L = none or an oxygen atom,
L ′ is defined similarly to L, and L ′ = L or L ′ ≠ L.
The degree of polymerization of the two-dimensional polymer is not particularly limited, but from the viewpoint of a decrease in solubility in the electrolyte, the degree of polymerization n is required to be n ≧ 2, and the polymer is In some cases, it is difficult to synthesize polymers that are insoluble and n exceeds 8, and as the number of n increases, the relative content of cyano groups, that is, [number of cyano groups / molecular weight] decreases, and the acceptability of the polymer decreases. In view of the fact that the potential of the cathode half-cell reaction moves in a negative direction (moves in a direction in which the output of the battery decreases), n = 3 to 6 is most preferable. The degree of polymerization n is the “number of repeating structures” of the unit structure composed of one phthalocyanine or pyrazinocyanine ring skeleton and one bidentate ligand L in the above (Chemical Formula 1). The number of M contained in the polymer] + [the number of M ′ contained in the polymer]. That is, the unit repeating structure corresponds to the portion surrounded by the dotted line in the above (Chemical Formula 1).

In producing a lithium (ion) secondary battery using the above-mentioned cathode material, conventionally known anodes and electrolytes can be appropriately employed. Specific examples of the anode include metallic lithium, lithium / aluminum alloy, and graphite lithium (Li · Gp). The electrolyte is a lithium salt such as a lithium hexafluorophosphate (LiPF ₆ ) organic solvent solution. And a film in which the polymer gel is impregnated.

The cathode material is kneaded with the cathode material (two-dimensional polymer) of the present invention, current-collecting particles such as acetylene black, and a binder such as polyvinylidene fluoride (abbreviated as PVDF). -Use a dried thin film. In addition, the ratio of the two-dimensional polymer of the present invention is not particularly limited, but is preferably about 50 to 85 wt% with respect to the entire cathode member. When the amount of the current-collecting particles such as acetylene black is too large, the capacity is reduced. On the other hand, when the amount is too small, the internal impedance is increased. The amount of the binder may be a minimum amount as long as it can bind the cathode material and the current collecting particles, and is approximately 25 wt% or less, preferably 5 to 15 wt%.
It is.

[0010]

The present invention will be described in more detail with reference to the following examples. Examples 1 to 12 are examples of synthesizing the two-dimensional polymer according to the present invention, and Examples 13 to 36 are examples of manufacturing a lithium secondary battery using the two-dimensional polymer. (Example 1) 1.0 g of tetracyanobenzene (abbreviated as TCB)
(5.6 mmol) was dissolved in 35 ml of sulfolane, and 0.05 ml of diazabicycloundecene was added thereto.
The reaction was allowed to proceed for an hour, and the mixture was poured into about 1 liter of chloroform, and a black-green precipitate was collected by filtration. It was dissolved in a minimum amount of DMF and purified by reprecipitation in chloroform to obtain 0.90 g (yield: 90%) of octacyano metal-free phthalocyanine (hereinafter, H ₂ PcOC). TOF-Mass spectrum: m / z = 714 (molecular weight = 714.6). Total amount of H ₂ PcOC and TCB
After mixing 0.68 g (3.8 mmol) in (*) DMF and drying under reduced pressure, the mixture was reacted at 250 ° C. for 3 hours, and then at 300 ° C. for 2 hours,
Wash with DMF and chloroform for insoluble black-green solid 6
30 mg were obtained. The amount of nitrile was determined by titration with dibutylaluminum hydride.
It was confirmed that the polymer was a two-dimensional polymer having M '= H ₂ , X = X' = C, L = none, and n = 3.1.

Example 2 1.0 g of tetracyanobenzene
(5.6 mmol) and 0.24 g (1.4 mmol) of anhydrous ferrous acetate are dissolved in 35 ml of sulfolane, and 0.05 ml of dissabicycloundecene is added. The mixture is reacted at 135 ° C. for 2 hours under a nitrogen stream, about 1 l.
The mixture was poured into chloroform, and a black-green precipitate was collected by filtration. The residue was dissolved in a minimum amount of DMF and purified by reprecipitation in chloroform to obtain 1.1 g (70% yield) of octacyanoiron phthalocyanine (hereinafter referred to as FePcOC). TOF-Mass spectrum: m / z = 768 (molecular weight
= 768.5). FePcOC total amount, bis (acetylacetonato) iron (II)
The reaction was carried out in the same manner as in Example 1 using 0.22 g (1.41 mmol) of the complex and 0.75 g (4.2 mmol) of TCB, and 820 m of an insoluble black green solid was obtained.
g was obtained. When the amount of nitrile was determined in the same manner as in Example 1 and the Fe content was determined by atomic absorption analysis of the calcined product, M = M ′ = Fe, X = X ′ = C, L = none, n = = 4.5 was confirmed as a two-dimensional polymer.

Example 3 Cobalt octacyanophthalocyanine (hereinafter referred to as CoPcOC) 0.86 was obtained by using cobalt acetate anhydrous 0.25 g (1.4 mmol) instead of ferrous acetate anhydrous.
g (yield 80%) [TOF-Mass spectrum: m / z = 771 (molecular weight = 771.6)], the total amount of which is 0.18 g (1.1 mmol) of bisacetylacetonatocobalt (II), 0.80 g of TCB ( 657 mg of an insoluble black-green solid was obtained in the same manner as in Example 2 except that the reaction was carried out with 4.5 mmol). The amount of nitrile was determined in the same manner as in Example 1,
When the Co content was determined from the atomic absorption analysis of the calcined product,
In (Chemical Formula 1), it was confirmed that the polymer was a two-dimensional polymer in which M = M '= Co, X = X' = C, L = none, and n = 3.5.

(Example 4) Nickel octacyanophthalocyanine (hereinafter NiPcOC) 0.86 using 0.25 g (1.4 mmol) of nickel acetate anhydride instead of ferrous acetate anhydride.
g (80% yield) [TOF-Mass spectrum: m / z = 771 (molecular weight = 771.5)], the total amount of which is 0.18 g (1.1 mmol) of bisacetylacetonatonickel (II), 0.80 g of TCB ( 740 mg of an insoluble black-green solid was obtained in the same manner as in Example 2 except that the reaction was carried out with 4.5 mmol). The amount of nitrile was determined in the same manner as in Example 1,
When the Ni content was determined from the atomic absorption analysis of the calcined product,
In the chemical formula 1, it was confirmed that the polymer was a two-dimensional polymer in which M = M ′ = Ni, X = X ′ = C, L = none, and n = 4.8.

(Example 5) Tetracyanopyrazine (hereinafter, TCP) 1.0 g (5.6 mmol) was used instead of TCB, and copper acetate anhydrous 0.25 g (1.4 mmol) was used instead of ferrous acetate anhydrous. Copper octacyanopyrazinocyanine (hereinafter referred to as CuPycO
C) 0.98 g (90% yield) was obtained [TOF-Mass spectrum: m / z =
784 (molecular weight = 784.1)], the total amount of which is 0.21 g (1.3 mmol) of copper (II) bisacetylacetonate, 0.90 g (5.0 mmol) of TCP
In the same manner as in Example 2 except that the reaction was carried out, 720 mg of an insoluble black-green solid was obtained. When the amount of nitrile was determined in the same manner as in Example 1, and the copper content was determined by atomic absorption analysis of the calcined product, it was found that in Chemical Formula 1, M = M ′ = Cu, X = X ′ = N, L = none, n =
It was confirmed to be a two-dimensional polymer of 5.2.

Example 6 0.55 g of zinc octacyanopyrazinocyanine (hereinafter ZnPycOC) (yield 50%) was obtained by using 0.25 g (1.4 mmol) of zinc acetate anhydrate instead of ferrous acetate anhydrate. ) To obtain [TOF-Mass spectrum: m / z = 786 (molecular weight =
786.0)], and the whole amount is zinc bisacetylacetonato (II)
420 mg of an insoluble black-green solid in the same manner as in Example 5 except that it was reacted with 0.17 g (0.70 mmol) and 0.50 g (2.8 mmol) of TCP.
I got The amount of nitrile was determined in the same manner as in Example 1, and the Zn content was determined by atomic absorption analysis of the calcined product.
It was confirmed that the polymer was a two-dimensional polymer having M = M ′ = Zn, X = X ′ = N, L = none, and n = 4.2.

(Example 7) 0.54 g of chromium octacyanopyrazinocyanine (hereinafter referred to as CrPycOC) using 0.24 g (1.4 mmol) of chromium acetate anhydride instead of ferrous acetate anhydride.
(TOF-Mass spectrum: m / z = 772 (molecular weight = 772.6)), and the whole amount was 0.17 g (0.70 mmol) of bisacetylacetonatochromium (II) and 0.50 g (2.8%) of TCP. mmol) to obtain 400 mg of an insoluble black-green solid in the same manner as in Example 5. The amount of nitrile was determined in the same manner as in Example 1,
Also, when the Zn content was determined from atomic absorption analysis of the fired product,
In the chemical formula 1, it was confirmed that the polymer was a two-dimensional polymer in which M = M ′ = Cr, X = X ′ = N, L = none, and n = 3.6.

Example 8 0.24 g of bisacetylacetonatooxovanadium (1.4 g) was used in place of ferrous acetate anhydrate.
mmol) to obtain 0.77 g (yield 70%) of oxovanadium octacyanopyrazinocyanine (hereinafter referred to as VOPycOC) [TO
F-Mass spectrum: m / z = 787 (molecular weight = 787.5)], and the total amount thereof was bisacetylacetonatooxovanadium (II) 0.16.
g (0.97 mmol) and TCP 0.70 g (3.9 mmol), except that 590 mg of an insoluble black-green solid was obtained in the same manner as in Example 5. When the amount of nitrile was determined in the same manner as in Example 1, and the V content was determined by atomic absorption analysis of the calcined product, M = M ′ = V, X = X ′ = N, L = L ′ = It was confirmed that the polymer was a two-dimensional polymer having O and n = 5.2.

Example 9 0.23 g of bisacetylacetonatooxotitanium (1.4 g) was used instead of anhydrous ferrous acetate.
mmol) to obtain 0.65 g (60% yield) of oxotitanium octacyanopyrazinocyanine (hereinafter referred to as "TiOPycOC").
OF-Mass spectrum: m / z = 784 (molecular weight = 784.4)], and the total amount thereof is bisacetylacetonatooxotitanium (II) 0.1.
Except having reacted with 14 g (0.83 mmol) and 0.60 g (3.3 mmol) of TCP, it carried out similarly to Example 5, and obtained 500 mg of insoluble black-green solids. When the amount of nitrile was determined in the same manner as in Example 1, and the Zn content was determined by atomic absorption analysis of the calcined product, it was found that in Chemical Formula 1, M = Ti, X = X ′ = N, L = L ′ = O, n = 4.8 was confirmed as a two-dimensional polymer.

Example 10 1.0 g (1.4 mmol) of H ₂ PcOC which is an intermediate obtained in Example 1, 0.19 g (1.20 mmol) of iron (II) bisacetylacetonato, 0.70 g (3.9 mmol) of TCB ) Was performed in the same manner as in Example 1 except for using (*), to obtain 530 mg of an insoluble black-green solid. The amount of nitrile was determined in the same manner as in Example 1, and the atomic absorption analysis of the calcined product showed Fe
When the content was determined, in the chemical formula 1, M = H ₂ , M ′ = Fe,
It was confirmed that the polymer was a two-dimensional polymer in which X = C, L = none, and n = 5.2.

Example 11 1.1 g (0.98 mmol) of FePcOC, an intermediate obtained in Example 2, 0.24 g (1.4 mmol) of bisacetylacetonatooxovanadium, and 0.69 g (3.8 m) of TCP
550 mg of an insoluble black-green solid was obtained in the same manner as in Example 1 except for using (mol). The amount of nitrile was determined in the same manner as in Example 1, and the Fe content was determined by atomic absorption analysis of the calcined product.
It was confirmed that the polymer was a two-dimensional polymer having M '= V, X = C, X' = N, L = none, L '= O, and n = 3.9.

(Example 12) VOPycO obtained in Example 8
C1.0g (1.3mmol) and bisacetylacetonatocobalt (I
I) Except that 0.19 g (1.20 mmol) and 0.70 g (3.9 mmol) of TCB were used, the operations after (*) in Example 1 were performed in the same manner to obtain 560 mg of an insoluble black-green solid. When the amount of nitrile was determined in the same manner as in Example 1, and the Fe content was determined by atomic absorption analysis of the calcined product, M = V, M ′ = Co, X = C, X ′ =
It was confirmed that the polymer was a two-dimensional polymer having N, L = O, L ′ = none, and n = 4.9.

Example 13 A lithium metal foil (anode) having a thickness of 1300 μm and 16 mmφ, a porosity impregnated with a 0.5 M LiPF ₆ dimethoxyethane (DME) solution = 37%, and a thickness of 25 μm
And a cathode formed by molding a two-dimensional polymer obtained in Example 1, 60 wt% of the two-dimensional polymer, 25 wt% of acetylene black and 15 wt% of polyvinylidene fluoride (PVDF) to a thickness of 100 μm into a 2016 button type battery, and a discharge end voltage of 1.0 A constant current charge / discharge test was performed at V, a charge termination voltage of 4.2 V, and a discharge rate of 0.5 C. As a result, the open circuit voltage = 3.81 V, the average output = 1.80 V, the cathode capacity = 850 mAh / g, the cathode energy density = 1530 Wh / kg, the number of times of charge and discharge when the energy density decreases to 80% of the maximum value = 1650 The following battery was obtained.

(Examples 14 to 24) A charge / discharge test was performed in the same manner as in Example 13 except that the two-dimensional polymers of Examples 2 to 12 were used, and the results shown in Table 1 were obtained.

[0024]

[Table 1]

(Example 25) 75 wt% of graphite powder of about 400 mesh and 25 wt% of PVDF were molded to a thickness of 500 μm.
Lithium graphite (Gp · Li) in which lithium is discharged as an intercalation compound in graphite by discharging lithium metal as an anode in a 5M LiPF ₆ -DME electrolyte solution
Electrodes were made. A battery system was prepared in the same manner as in Example 13 except that the Gp / Li electrode was used as the anode, and the discharge end voltage was set to 1.0.
A constant current charge / discharge test was performed at V, a charge termination voltage of 4.2 V, and a discharge rate of 0.5 C. As a result, open voltage = 3.70 V, average output =
A lithium ion secondary battery having 1.71 V, a cathode capacity of 860 mAh / g, a cathode energy density of 1470 Wh / kg, and a charge / discharge cycle of 2350 times at which the energy density was reduced to 80% of the maximum value was obtained.

Examples 26 to 36 A charge / discharge test was performed in the same manner as in Example 25 except that the two-dimensional polymers of Examples 2 to 12 were used, and the results shown in Table 2 were obtained.

[0027]

[Table 2]

[0028]

As described above, the cathode material of the present invention exhibits a high capacity of 580 to 940 mAh / g and an energy density of 980 to 1950 Wh / kg in a cathode half-cell reaction. ] Type lithium secondary battery, average output 1.64 ~ 2.07V, capacity 580 ~ 940mAh / g,
Energy density 980 ~ 1950Wh / kg, average output 1.58 ~ 1.99V, capacity 590 ~ 930mAh / g, energy density as lithium-ion secondary battery in the form of [Li-Gp / electrolyte / one-dimensional polymer]
High capacity and high energy density of 930-1850Wh / kg can be achieved. This high-capacity, high-energy-density lithium (ion) secondary battery can be mounted on various portable electronic devices as a power source having a long life and excellent repetitive charge / discharge characteristics.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mihiro Asai 2-11-4 Higashicho, Koganei-shi, Tokyo (72) Inventor Ken Satoshi 2-22-1402 Wakabadai, Asahi-ku, Yokohama-shi, Kanagawa F-term (reference) 5H029 AJ05 AK16 AL07 AL12 AM00 AM02 AM07 AM16 HJ02 5H050 AA07 BA16 BA17 CA22 CB08 CB12 HA02

Claims (3)

[Claims] 1. Poly [cyano (metal) phthalocyanine] to poly [cyano (metal) as shown in the following
Material for a cathode comprising a dimer or higher oligomer or a two-dimensional polymer of pyrazinocyanine]. Embedded image However, in (Chemical Formula 1), M = H ₂ or a transition metal ion of Groups 4 to 12 in the periodic table, M ′ is defined in the same manner as M, and M ′ = M or M ′ ≠.
M, X = C or N, X ′ is defined as X, X ′ = X or X ′ ≠ X, L = no or oxygen atom, L ′ is the same as L Defined, L '= L or L' ≠ L
It is. 2. A lithium secondary battery comprising the material according to claim 1 in a cathode member. 3. A lithium ion secondary battery comprising the material according to claim 1 in a cathode member.