JP2003017058A - Non-aqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-aqueous electrolyte battery having a large capacity, a high voltage and excellent cycle characteristics by using Al or an Al alloy for a negative electrode thereof. SOLUTION: This non-aqueous electrolyte battery has a positive electrode having a positive electrode active material, a negative electrode provided with aluminum or the aluminum alloy, and the non-aqueous electrolyte interposed between the positive electrode and the negative electrode. As the positive electrode active material, a metal compound expressed in a general formula Alz My (XO4 )n is used. (M means Fe, Co, Mn, Ni, Cu, Li, Na or K atom. X means S, P, Mo, W or V atom, z is 0 or more, y is 1 or more, and n is 1 or more).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte battery which uses aluminum or an aluminum alloy for a negative electrode and has a high capacity, a high voltage and excellent cycle characteristics.

[0002]

2. Description of the Related Art Recently, non-aqueous electrolytic secondary batteries using lithium compounds such as lithium metal, lithium alloys, metal oxides capable of inserting and extracting lithium ions in the negative electrode, and carbon materials are high energy density batteries. Therefore, research and development for high capacity have been actively carried out.

In particular, when a carbon material is used for the negative electrode, although the negative electrode capacity is lower than that of lithium metal, long life and high safety can be obtained. Therefore, for example, lithium cobalt oxide is used as the positive electrode, and The lithium ion battery used as the negative electrode has been widely put into practical use as a power source for driving mobile phones.

However, when a material capable of inserting and extracting lithium metal or lithium ions is used for the negative electrode, the battery voltage can be increased, so that the energy density is higher than that of the conventional primary battery or secondary battery. However, it was difficult to obtain a battery having both higher capacity and longer life.

Therefore, studies have been made on high-capacity primary batteries and secondary batteries using magnesium, calcium, aluminum, etc. in addition to lithium metal, but since the negative electrode and the electrolytic solution are easily reacted, Although research on a positive electrode active material with a large capacity is underway, it has not yet been developed as a product.

[0006]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a non-aqueous electrolyte primary battery or secondary battery which uses aluminum or an aluminum alloy for the negative electrode and has a high capacity, a high voltage, and excellent cycle characteristics. To do.

[0007]

The present inventors SUMMARY OF THE INVENTION As a result of extensive research in view of the above problems, an aluminum or aluminum alloy in the negative electrode, as a positive electrode active material, the general formula Al z _M y _{(XO 4} ) The present invention is completed based on the finding that a non-aqueous electrolyte primary battery or secondary battery having high capacity, high voltage, and excellent cycle characteristics can be obtained by using the metal compound represented by _n. It came to.

That is, the non-aqueous electrolyte battery of the present invention is
In a non-aqueous electrolyte battery having a positive electrode having a positive electrode active material, a negative electrode including aluminum or an aluminum alloy, and a non-aqueous electrolytic solution sandwiched between the positive electrode and the negative electrode, the positive electrode active material is represented by the general formula Al _z M _{y (XO 4) n}
A metal compound represented by (M in the formula is Fe, Co, Mn,
At least 1 selected from Ni, Cu, Li, Na and K
X represents at least one atom selected from S, P, Mo, W and V, and z represents a number of 0 or more,
y is a number of 1 or more, and n is a number of 1 or more. ), Is characterized by. Furthermore, it is preferable that the non-aqueous electrolyte solution be composed of an ambient temperature molten salt containing an aluminum salt or an organic solvent containing an aluminum salt.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION [I] Non-Aqueous Electrolyte Battery (1) Structure As shown in FIG. 1, the structure of the non-aqueous electrolyte battery of the present invention comprises a storage container and a positive electrode stored in the storage container. It basically consists of a negative electrode housed in the container and a non-aqueous electrolyte solution housed in the container.

[0010] As the active material of positive electrode, M in the general formula _Al z _M y _{(XO 4)} metal compound represented by _n (in the formula in the present invention is Fe, V, Co, Mn, Ni, Cu, L
at least one atom selected from i, Na and K is replaced by X
Represents at least one atom selected from S, P, Mo, W and V, z is a number of 0 or more, y is a number of 1 or more, and n is a number of 1 or more. It is important to use a metal compound represented by Further, the non-aqueous electrolyte solution,
It is preferable to use an ambient temperature molten salt containing an aluminum salt or an organic solvent containing an aluminum salt.

(2) Constituent members The constituent members of the positive electrode, the negative electrode, the non-aqueous electrolyte, the separator, and the storage container, which are the constituent members of the non-aqueous electrolyte battery of the present invention, will be described in detail below.

(A) Positive Electrode This positive electrode has a positive electrode current collector and a positive electrode active material layer which is carried on one side or both sides of the current collector and contains an active material and a binder.

The positive electrode active material the positive electrode active material has the general formula _Al z _M y _{(XO 4)} metal compound represented by _n (where M in the formula Fe, V, Co, Mn,
At least 1 selected from Ni, Cu, Li, Na and K
X is at least one atom selected from S, P, Mo, W and V, z is a number of 0 or more, y is a number of 1 or more, and n is a number of 1 or more. is there. ).

The metal compound represented by Al _z M _y (XO ₄ ) _n has a large gap between elements structurally, and the absorption and desorption of aluminum ions are promptly performed. M is an element capable of energy units occluding and releasing aluminum ions, and _is an element capable of having a structure of _{Al z M y (XO 4)} n.

Among these metal compounds, M is Fe, C
It is preferable to use those represented by o, Li, and Mn, and particularly preferable to use those represented by Fe, Co, and Li atoms. In addition, among the metal compounds, X is
It is preferable to use those represented by S, V and P.

Further, y in the above general formula is preferably a number of 1 or more, and particularly preferably a number in the range of 0.5 to 2. n is a number of 1 or more,
A number in the range of 1 to 3 is particularly preferable. z is usually 0 in the initial state, and is contained in the metal compound as a result of aluminum being intercalated during use of the battery. Especially when the battery is used as a secondary battery, the aluminum content does not affect the battery performance.

Among these metal compounds, in the undischarged state
As the positive electrode active material, Fe_Two(SO _Four)_Three, Fe_Two(M
oO_Four)_Three, Fe_Two(WO_Four)_Three, LiCOVO_Four, L
iNiVO_Four, LiFe_0.5Mn_0.5PO_Four, Li
FePO_Four, LiCuVO_FourEtc. can be mentioned.

The positive electrode active material inserts aluminum ions during battery discharge to form a metal compound containing aluminum. Further, it functions as a secondary battery by releasing aluminum ions during charging. Since the battery electromotive force is in the range of 3V to 1V by using the positive electrode active material and the aluminum negative electrode, the positive electrode capacity can be increased by 2 to 3 times as compared with the case where lithium is used as the negative electrode. The capacity can be significantly increased.

Binder As the binder , for example, polytetrafluoroethylene (PTFE), polyfluorinated ethylene (PVdF),
Fluorine-based rubber or the like can be used.

Conducting Agent The positive electrode active material layer may further contain a conducting agent.
Examples of such a conductive agent include acetylene black, carbon black, graphite and the like.

Blending Ratio The blending ratio of the positive electrode active material, the conductive agent and the binder is generally 80 to 98% by weight, preferably 90 to 95% by weight, the positive electrode active material, 3 to 20% by weight, preferably 3 to. 8% by weight,
It is preferable that the binder content is in the range of 2 to 7% by weight, preferably 2.5 to 6% by weight.

Current Collector As the current collector of the positive electrode, a metal foil having a thickness of 1 to 20 μm or the like is used. Among these metal foils, it is preferable to use a metal foil coated with stainless steel, nickel, iron, molybdenum, tungsten, a carbon film, TiN, TiC, or the like.

Preparation of Positive Electrode For the positive electrode, for example, a positive electrode active material, a conductive agent and a binder are suspended in a suitable solvent, the suspension is applied to a current collector, dried and pressed. It is made.

(B) Negative Electrode In the present invention, it is important to use a metal foil or metal powder made of aluminum or an aluminum alloy as the negative electrode. The aluminum preferably has a purity of 99% or more. Examples of the aluminum alloy include an aluminum zinc alloy, an aluminum magnesium alloy, an aluminum chromium alloy, and an aluminum manganese alloy. The thickness of the aluminum or aluminum alloy metal foil is preferably 10 to 300 μm. The average particle diameter of the metal powder of aluminum or aluminum alloy is 5 to 500 μm, particularly 10
˜300 μm is preferred. The metal powder is
It is mixed with a binder such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF) and fluororubber, and suspended in an appropriate solvent. This suspension is applied to a metal foil current collector made of stainless steel, nickel, iron, copper or the like, dried, and pressed.

(C) Non-Aqueous Electrolyte As this non-aqueous electrolyte, it is preferable to use an electrolytic solution comprising an ambient temperature molten salt containing an aluminum salt or an organic solvent containing an aluminum salt.

(A) Aluminum Salt Examples of the aluminum salt include aluminum halides such as AlCl ₃ , aluminum nitrate, aluminum sulfate, Al (BF ₄ ) ₃ , Al (PF ₆ ) ₃ , and Al (Cl
O ₄ ) ₃ , Al (CF ₃ SO ₃ ) ₃ , Al ((C ₂ F ₅
SO _{2) 2} N) ₃ and the like. In addition to the above aluminum salt, ammonium salt or lithium salt may be added. Examples of the ammonium salt include tetraethylammonium chloride. As the lithium salt, LiCl, LiBF ₄ , LiPF ₆ , LiC
lO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ).
_{2 N, Li (C 2 F} 5 SO 2) can be cited ₂ N or the like.

(B) Room temperature molten salt As the room temperature molten salt, it melts at room temperature and below room temperature.
It is an ionic melt. The aluminum salt and imidazo
From a mixed salt with an organic salt such as a lithium salt or a pyridinium salt
Become. As the imidazolium salt, 1-ethyl-3
-Methylimidazolium cation (EMI⁺) And C
l⁻, BF_Four ⁻, PF₆ ⁻, ClO_Four ⁻, CF_ThreeSO₃
⁻, (CF_ThreeSO_Two)_TwoN⁻, (C_TwoF₅SO_Two)_TwoN
⁻An organic salt composed of an anion such as
Examples of the pyridinium salt include 1-butylpyridinium
Cation (BP⁺) And (Cl⁻), BF_Four ⁻, P
F₆ ⁻, ClO_Four ⁻, CF_ThreeSO₃ ⁻, (CF_ThreeS
O _Two)_TwoN⁻, (C_TwoF₅SO_Two)_TwoN⁻Anions such as
The organic salt consisting of

(C) Organic solvent As the organic solvent, propylene carbonate (P
Cyclic carbonates such as C), diethyl carbonate (D
Chain carbonates such as EC), γ-butyrolactone (γ
-BL), acetonitrile (AN), sulfolane (S
L), sulphonenes, cyclic ethers, chain ethers and the like.

(D) Mixing ratio The mixing ratio (molar ratio) of the aluminum salt and the organic salt or the organic solvent is in the range of 1:15 to 3: 1, particularly 1:10 to 2: 1. It is preferable. The room temperature molten salt containing the aluminum salt or the organic solvent containing the aluminum salt may be in the form of gel by adding a polymer material in addition to the liquid state. By using a room temperature molten salt containing an aluminum salt and an organic solvent as the non-aqueous electrolytic solution used in the non-aqueous electrolytic solution battery of the present invention, an aluminum ion (aluminum complex ion) in the electrolytic solution inserts into the positive electrode. Since it can be performed smoothly, it is possible to draw out a large amount of power. On the other hand, in the negative electrode, the dissolution and precipitation reaction of aluminum can be efficiently carried out, and the cycle life can be dramatically improved.

(D) Separator In the non-aqueous electrolyte battery of the present invention, a separator can be arranged between the positive electrode and the negative electrode. The separator is
A liquid or gel non-aqueous electrolyte can be retained. Examples of the separator include polyethylene,
Examples thereof include a porous film containing polypropylene, cellulose, or polyvinylidene fluoride (PVdF), a synthetic resin nonwoven fabric, and the like. These porous films generally have a thickness of 5 to 100 μm, preferably 10 to 30 μm. Among these, polyethylene, polypropylene, or a porous film made of both is preferable because the safety of the secondary battery can be improved.

(E) Storage Container The storage container may have any shape such as a bottomed cylindrical shape, a bottomed square shape, a coin shape, a button shape, and a film shape. As a material forming the storage container, a metal can or a laminated film can be used.

[0032] Metal cans the metal can, for example, iron, stainless steel, metal cans and the inner surface of the metal can, such as nickel can be used as the insulated coated with a resin. The metal layer has a thickness of 10
It is preferably formed from an aluminum foil having a thickness of 150 μm.

Laminate Film The laminate film preferably includes a metal layer and a resin layer that covers one side or both sides of the metal layer. The thickness of the film is preferably in the range of 50 to 250 μm. Meanwhile, the resin layer may be formed of a thermoplastic resin such as polyethylene or polypropylene. The resin layer may have a single-layer structure or a multi-layer structure.

[II] Application The non-aqueous electrolyte battery of the present invention has a high capacity, a high voltage, and excellent cycle characteristics. Therefore, it is a primary battery or a secondary battery of a mobile phone driving power source. It can be widely used industrially.

[0035]

EXAMPLES The present invention will be described in more detail with reference to the following examples and comparative examples. As an example of the non-aqueous electrolyte battery of the present invention, a cylindrical non-aqueous electrolyte battery will be cited as one of its specific examples, and will be specifically described with reference to FIG.

[I] Evaluation Method (1) As the electromotive force of the electromotive force battery, an open circuit potential after the battery was manufactured was measured.

(2) Discharge capacity The discharge capacity of the battery is 1 V at constant current discharge of 50 mA.
It was measured by discharging to.

(3) Cycle life The cycle life of a battery is determined by the number of times of charge that can be charged up to 1 V by repeating charging / discharging by discharging up to 1 V at a discharge current of 50 mA and charging up to 3 V at a charging current of 50 mA. It was measured as cycle life.

[II] Examples and Comparative Examples Example 1 EB in FIG. 1 is a non-aqueous electrolyte battery, and 1 is a bottomed cylindrical stainless steel container in which an insulator 2 is arranged at the bottom.
The electrode group 3 is housed in the container 1. The electrode group 3 has a structure in which a band-shaped material in which a positive electrode 4, a separator 5, and a negative electrode 6 are laminated in this order is spirally wound so that the negative electrode 6 is located outside. The battery EB has an outer diameter of 1
The size is 4 mm and the height is 50 mm.

Positive electrode The positive electrode 4 was composed of 91% by weight of iron sulfate (Fe ₂ (SO ₄ ) ₃ ) powder, 2.5% by weight of acetylene black, 3% by weight of graphite, and 4% of polyvinylidene fluoride (PVdF).
Wt% and N-methylpyrrolidone (NMP) solution were added and mixed, and applied on a TiN-coated stainless steel foil collector having a thickness of 15 μm, dried, and pressed to obtain an electrode density of 2.5 g / cm 2. A strip-shaped positive electrode of No. ³ was produced.

Separator As the separator 5, a polyethylene porous film having a thickness of 20 μm was used.

Negative Electrode The negative electrode 6 contains 90% by weight of 99.99% pure aluminum powder having an average particle size of 30 μm, 5% by weight of acetylene black, and 5% by weight of polyvinylidene fluoride (PVdF).
A N-methylpyrrolidone (NMP) solution was added and mixed, coated on a 15 μm-thick Steres foil, dried, and pressed to produce a strip-shaped negative electrode having an electrode density of 2 g / cm ³ .

Electrolyte In the container 1, aluminum chloride (AlCl ₃ ) and 1-ethyl-3-methylimidazolium chloride (EM) were used.
The normal temperature molten salt in which IC) is mixed at a molar ratio of 2: 1 is stored as an electrolyte.

Insulating Paper On the electrode group 3, an insulating paper 7 having a central opening is installed.

Positive electrode terminal Furthermore, an insulating sealing plate 8 is provided in the upper opening of the container 1 in a liquid-tight manner by caulking the container 1 or the like,
A positive electrode terminal 9 is joined to the center of the insulating sealing plate 8. The positive electrode terminal 9 is connected to the positive electrode 4 of the electrode group 3 via a positive electrode lead 10. The electrode group 3
The negative electrode 6 is connected to the container 1, which is a negative electrode terminal, through a negative electrode lead (not shown).

Measurement of electromotive force, discharge capacity and cycle life The electromotive force, discharge capacity and cycle life of the obtained battery were measured by measuring the electromotive force, initial capacity and capacity retention rate after 100 cycles. did. The results are shown in Table 1.

Example 2 Except that Fe ₂ (MoO ₄ ) ₃ was used as the positive electrode active material,
A non-aqueous electrolyte solution similar to that of Example 1 was prepared, and the electromotive force, discharge capacity and cycle life of the battery were measured. The results are shown in Table 1.

Example 3 A non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that Fe ₂ (WO ₄ ) ₃ was used as the positive electrode active material, and the electromotive force, discharge capacity and cycle life of the battery were measured. did.
The results are shown in Table 1.

Example 4 A nonaqueous electrolyte battery similar to that of Example 1 was prepared except that LiCoVO ₄ was used as the positive electrode active material, and the electromotive force, discharge capacity and cycle life of the battery were measured. The results are shown in Table 1.

Example 5 A non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that LiFe _0.5 Mn _0.5 PO ₄ was used as the positive electrode active material, and the electromotive force, discharge capacity and cycle life of the battery were prepared. Was measured respectively. The results are shown in Table 1.

Example 6 A non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that LiNiVO ₄ was used as the positive electrode active material, and the electromotive force, discharge capacity and cycle life of the battery were measured. The results are shown in Table 1.

Example 7 A non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that LiFePO ₄ was used as the positive electrode active material, and the electromotive force, discharge capacity and cycle life of the battery were measured. The results are shown in Table 1.

Example 8 A nonaqueous electrolyte battery similar to that of Example 1 was prepared except that LiCuPO ₄ was used as the positive electrode active material, and the electromotive force, discharge capacity and cycle life of the battery were measured. The results are shown in Table 1.

Comparative Example 1 A nonaqueous electrolyte battery was prepared in the same manner as in Example 1 except that MnO ₂ was used as the positive electrode active material, and the electromotive force, discharge capacity and cycle life of the battery were measured. The results are shown in Table 1.

Comparative Example 2 Example 1 except that LiCoO ₂ was used as the positive electrode active material.
A non-aqueous electrolyte battery similar to that was prepared, and the electromotive force, discharge capacity and cycle life of the battery were measured. The results are shown in Table 1.

Comparative Example 3 Example 1 except that polyaniline was used as the positive electrode active material.
A non-aqueous electrolyte battery similar to that was prepared, and the electromotive force, discharge capacity and cycle life of the battery were measured. The results are shown in Table 1.

[0057]

[Table 1] As is clear from Table 1, the non-aqueous electrolyte batteries of Examples 1 to 8 have higher capacities, higher voltages, than the batteries of Comparative Examples 1 to 3.
It can be seen that it has a long life.

[0058]

The non-aqueous electrolyte battery of the present invention has a high capacity,
Since it is a non-aqueous electrolyte battery with high voltage and excellent cycle characteristics, it can be widely used as a power source for driving mobile phones.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a cylindrical non-aqueous electrolyte battery of the present invention used in Example 1.

[Explanation of symbols]

1 stainless steel container 2 insulator 3 electrode group 4 positive electrode 5 separator 6 Negative electrode 7 insulating paper 8 Insulation sealing plate 9 Positive terminal 10 Positive electrode lead EB non-aqueous electrolyte battery

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) H01M 6/16 H01M 6/16 Z 10/40 10/40 AZ F Term (Reference) 5H024 AA02 AA11 CC02 CC12 DD14 FF15 FF19 5H029 AJ02 AJ03 AJ05 AK03 AL11 AM03 AM04 AM07 BJ02 BJ14 HJ02 5H050 AA02 AA07 AA08 BA06 BA17 CA07 CB11 DA02 DA13 FA05 HA02

Claims (2)

[Claims] 1. A non-aqueous electrolyte battery comprising a positive electrode having a positive electrode active material, a negative electrode comprising aluminum or an aluminum alloy, and a non-aqueous electrolytic solution sandwiched between the positive electrode and the negative electrode, wherein the positive electrode active material. the general formula _Al z _{M y}
A metal compound represented by (XO ₄ ) _n (M in the formula is Fe,
At least one atom selected from Co, Mn, Ni, Cu, Li, Na and K, X represents at least one atom selected from S, P, Mo, W and V, and z is 0 or more. , Y is a number of 1 or more, and n is a number of 1 or more. ) Is a non-aqueous electrolyte battery. 2. The non-aqueous electrolyte solution according to claim 1, wherein the non-aqueous electrolyte solution comprises a room temperature molten salt containing an aluminum salt or an organic solvent containing an aluminum salt. battery.