JP2003338316A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery whereof low temperature discharge characteristics and cycle life characteristics are enhanced. <P>SOLUTION: Graphite is used for the negative electrode of this nonaqueous electrolyte secondary battery, and ethylene-carbonate and chain carbonate are used for nonaqueous electrolyte. The rate of the volume of ethylene-carbonate to total sum volume of ethylene-carbonate and chain carbonate is set at a range of 20-50 volume %. 0.1-2 wt.% of tetraethylammonium fluoride-tetrakis (hydrofluoride) [(C<SB>2</SB>H<SB>5</SB>)<SB>4</SB>NF.4HF] is added to the nonaqueous electrolyte. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte secondary battery.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 3115839 discloses a technique of adding a quaternary ammonium fluoride salt or the like to a non-aqueous electrolyte in a non-aqueous electrolyte secondary battery using a lithium metal negative electrode.

In this technique, a salt of quaternary ammonium fluoride or the like is added to uniformly form a coating film of Li ₂ O and LiF on the negative electrode. The uniform coating allows a current to flow evenly during charging / discharging to suppress the generation of dendrites due to current concentration, and as a result, to improve cycle life characteristics.

Further, according to this publication, even when a negative electrode made of a carbonaceous material is used, the addition of a quaternary ammonium fluoride salt or the like suppresses the generation of dendrites, resulting in cycle life characteristics. It is disclosed that the improvement of

[0005]

However, in a non-aqueous electrolyte secondary battery of a negative electrode made of a carbonaceous material, even if a salt of quaternary ammonium fluoride or the like is added,
Further, the cycle life characteristics cannot be said to be sufficient, and further improvement in low temperature discharge characteristics and cycle life characteristics has been earnestly desired.

The present invention was completed in view of the above circumstances, and an object thereof is to provide a non-aqueous electrolyte secondary battery having good low-temperature discharge characteristics and cycle life characteristics.

[0007]

The inventors of the present invention have made earnest studies and found that in a non-aqueous electrolyte secondary battery of a negative electrode made of a carbonaceous material, a salt of quaternary ammonium fluoride or the like was added to the electrolytic solution. However, the reason why the low-temperature discharge characteristic and the cycle life characteristic are not improved as expected was speculated as follows.

That is, when a salt of quaternary ammonium fluoride or the like is added, the formation of dendrite is surely suppressed, but the viscosity of the non-aqueous electrolyte is increased and the ionic conductivity is lowered, so that the low temperature discharge characteristics are improved. It was speculated that the cycle life characteristics did not improve as expected.

As a result of a more detailed study, in a non-aqueous electrolyte having a predetermined composition, SEI (Solid Electrolyte) formed on the surface of the negative electrode despite the increase in viscosity.
It has been found that low temperature discharge characteristics and cycle life characteristics are improved because the ionic conductivity of the interface film is very high. That is, when a salt of quaternary ammonium fluoride or the like is added, the viscosity increases and the ionic conductivity of the non-aqueous electrolyte decreases. However, in a non-aqueous electrolyte having a predetermined composition, the decomposition products of ethylene carbonate and chain carbonate form a film having very high ion conductivity due to the action of the salt of quaternary ammonium fluoride. Since the ionic conductivity of this coating had a great influence on the ionic conductivity of the entire system of the non-aqueous electrolyte secondary battery, even if the ionic conductivity of the non-aqueous electrolyte decreased, the ionic conductivity of the entire system It is considered that the low temperature discharge characteristic and the cycle life characteristic are improved. The present invention has been made based on this finding.

That is, the invention of claim 1 is a non-aqueous electrolyte secondary battery comprising a negative electrode containing a carbonaceous material, a positive electrode, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is ethylene carbonate and a chain-like structure. Hydrogen carbonate of quaternary ammonium fluoride containing carbonate, the volume ratio of ethylene carbonate to the total volume of ethylene carbonate and chain carbonate is 20% by volume to 50% by volume, and which is represented by the following general formula (4). At least one of a salt, a quaternary phosphonium fluoride hydrogen fluoride salt represented by the general formula (5), or a tertiary amine hydrofluoric acid represented by the general formula (6) is used for the non-aqueous electrolyte. The non-aqueous electrolyte secondary battery is characterized in that 0.1 wt% to 2 wt% is added.

[0011]

[Chemical 4] (Wherein, R1 and R2 are the general formula _{(C n H 2n + 1)} carbon number n represented by is in the range of 1 to 4 alkyl groups, coefficient of hydrogen fluoride and m is in the range of 1-6 )

[0012]

[Chemical 5] (In the formula, R3 and R4 are alkyl groups represented by the general formula (C _n H _{2n + 1} ) and having a carbon number n in the range of 1 to 4, and the coefficient m of hydrogen fluoride is in the range of 1 to 6. )

[0013]

[Chemical 6] (In the formula, R5 is an alkyl group represented by the general formula (C _n H _{2n + 1} ) and having a carbon number n in the range of 1 to 4, and the coefficient m of hydrogen fluoride is in the range of 1 to 6)

The invention according to claim 2 is the non-aqueous electrolyte secondary battery, wherein the chain carbonate is a mixture of diethyl carbonate and ethylmethyl carbonate.

In the present invention, the carbonaceous material contained in the negative electrode is not limited as long as it can occlude and release lithium, and examples thereof include known cokes, glassy carbons, graphites, and the like. Graphitizable carbons, pyrolytic carbons, carbon fibers and the like can be used alone or in admixture of two or more. Among these carbonaceous materials, graphite is particularly preferable due to its cycle life characteristics.

The positive electrode contains a positive electrode active material,
As the active material, a material capable of absorbing and releasing lithium
There is no particular limitation so long as it is, for example, LiCoO 2._Two, Li
NiO_Two, LiNi_1/2Mn_1/2O_Two, LiNi
_1/3Mn_1/3Co_1/3O _Two, LiCo_xNi
_1-xO_Two, LiMn_TwoO_Four, Li_TwoMn_TwoO_Four, Mn
O_Two, FeO_Two, V_TwoO₅, V₆O_Thirteen, TiO_TwoAlso
Is TiS_TwoEtc. can be used. These materials are
Do not use one kind alone or mix two or more kinds.
You can

The positive electrode and the negative electrode are laminated via a separator, and the separator is not particularly limited.
For example, woven cloth, non-woven cloth, synthetic resin microporous membrane, etc. can be used. In particular, a synthetic resin microporous film can be preferably used, and among them, a polyolefin-based microporous film such as a polyethylene and polypropylene microporous film, or a microporous film that is a composite of these can be used for the thickness, film strength, film resistance, etc. It is preferably used in terms of.

The non-aqueous electrolyte is not particularly limited as long as it contains a non-aqueous electrolyte, and the non-aqueous electrolyte can be used alone, or the solid electrolyte and the non-aqueous electrolyte can be used in combination. The non-aqueous electrolytic solution is obtained by dissolving an electrolyte salt in a non-aqueous solvent, and the non-aqueous solvent contains ethylene carbonate (EC) and chain carbonate as essential components. The ratio of ethylene carbonate to the total volume of ethylene carbonate and chain carbonate is 20% by volume to 50% by volume, preferably 2%.
It is 5 to 45% by volume, more preferably 30 to 40% by volume. This is because when the ratio of ethylene carbonate to the total volume of ethylene carbonate and chain carbonate is less than 20% by weight, the non-aqueous electrolyte is easily decomposed during charging / discharging, and the cycle life characteristics deteriorate. Also,
When the proportion of ethylene carbonate exceeds 50% by volume,
This is because the viscosity of the non-aqueous electrolyte increases, the lithium ion conductivity decreases, and the low-temperature discharge characteristics deteriorate.

The chain carbonate is not particularly limited and includes, for example, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, methylpropyl carbonate, methylisopropyl carbonate, methylbutyl carbonate, ethylpropyl carbonate, ethylisopropyl carbonate, ethylbutyl carbonate, dicarbonate. Propyl carbonate, diisopropyl carbonate, propyl butyl carbonate, dibutyl carbonate, etc. can be used. Among the chain carbonates, especially diethyl carbonate (DEC)
And a mixture of ethyl methyl carbonate (EMC) are preferred. This is because the low temperature discharge characteristics are further improved.

EM for the total volume of DEC and EMC
The volume ratio of C is preferably 10 to 70% by volume, more preferably 20 to 50% by volume, and further preferably 25 to
40% by volume. This is because the low temperature discharge characteristics are further improved.

The electrolyte salt is not particularly limited as long as it is an electrolyte salt usually used in non-aqueous electrolyte secondary batteries, and examples thereof include LiPF ₆ , LiClO ₄ , LiBF ₄ , LiAsF.
₆ , LiCF ₃ CO ₂ , LiCF ₃ (CF ₃ ) ₃ , L
_{iCF 3 (C 3 F 5)} 3, LiCF 3 SO 3, LiN
(SO ₃ CF ₃ ) ₃ , LiN (SO ₃ CF ₃ C
F ₃ ) ₃ , LiN (COCF ₃ ) and LiN (COC
Salts such as F ₃ CF ₃ ) ₃ and mixtures thereof can be mentioned. The concentration of these electrolyte salts is not particularly limited, but is preferably 0.5 to 2.0 mol / l, more preferably 0.8 to 1.7 mol / l, and further preferably 1.0 to 1.5 mol. / L.

Further, other organic solvents may be appropriately mixed and used as the non-aqueous solvent. Examples of other organic solvents include γ-butyrolactone, sulfolane, dimethylsulfoxide, acetonitrile, dimethylformamide, dimethylacetamide, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran,
2-Methyltetrahydrofuran, dioxolane, methyl acetate, vinylene carbonate, etc. can be used. Further, as the solid electrolyte, an inorganic solid electrolyte or a polymer solid electrolyte can be used.

In the present invention, the non-aqueous electrolyte includes the above-mentioned general compounds.
Compound of formula (4), general formula (5) or general formula (6)
(Additive) is added and is represented by the above general formula (4).
As quaternary ammonium fluoride hydrogen fluoride salt
Is, for example, tetraethylammonium fluoride-teto
Lakis (hydrofluoride) [(C_TwoH₅)_FourNF / 4H
F], [(CH_Three)_FourNF ・ 4HF] can be used.
The quaternary phosphonium fluoride represented by the general formula (5) above.
Examples of the hydrogen fluoride salt of lido include [(C_TwoH ₅)
_FourPF · 4HF] and the like, and the above general formula
As the tertiary amine hydrofluoric acid represented by (6),
For example, [(C_TwoH₅)_ThreeN.4HF]
it can. These compounds may be used alone, or
Two or more kinds can be mixed and used. A combination of these
Among the products, tetraethylammonium fluoride-teto
Lakis (hydrofluoride) [(C_TwoH₅)_FourNF / 4H
F] can be preferably used.

The amount of the additive added to the non-aqueous electrolyte is
It is in the range of 0.1 to 2.0% by weight, preferably 0.3.
˜1.5 wt%, and more preferably 0.5 to 1.2 wt%. The reason is that the additive amount is 0.1% by weight.
When the amount is less than the above, the cycle life characteristics are hardly improved, and when the amount added exceeds 2.0% by weight, the lithium ion conductivity of the non-aqueous electrolyte is deteriorated and the discharge characteristics are deteriorated. Is.

The shape of the non-aqueous electrolyte secondary battery is not particularly limited, and may be, for example, a cylindrical shape, a square shape, a coin shape or the like.

[0026]

EXAMPLES The present invention will be described in detail below with reference to examples. 1. Production of Non-Aqueous Electrolyte Secondary Battery The non-aqueous electrolyte secondary batteries in Examples 1 to 16 and Comparative Examples 1 to 14 were produced as follows. 1) Preparation of Negative Electrodes The negative electrodes used in the batteries of Examples 1 to 16, Comparative Examples 1 to 9, Comparative Example 12, and Comparative Example 13 were prepared as follows. 96 parts by weight of graphite as a negative electrode active material, 2 parts by weight of styrene-butadiene rubber as a binder, and 2 parts by weight of carboxymethyl cellulose also as a binder were kneaded together with water to prepare a negative electrode mixture paste. . This paste was evenly applied to both sides of a current collector made of a copper foil having a thickness of 10 μm, dried and pressed to form a negative electrode mixture layer, which was then cut to prepare a strip-shaped negative electrode sheet (Table 1, Table 1 2). The negative electrode sheets used in the batteries of Comparative Example 10, Comparative Example 11 and Comparative Example 14 were prepared by attaching a 20 μm thick metallic lithium foil to both sides of a 40 μm thick copper expanded metal current collector. It was made.

[0027]

[Table 1]

[0028]

[Table 2]

2) Preparation of positive electrode Cobalt lithium oxide (LiCo) as a positive electrode active material
O ₂ ) 87 parts by weight, polyvinylidene fluoride 8 parts by weight as a binder, and acetylene black 5 as a conductive agent.
Parts by weight were kneaded with N-methylpyrrolidone to prepare a positive electrode mixture paste. This paste is 20μ thick
m of aluminum foil was uniformly applied to both sides of the current collector, and a strip-shaped positive electrode sheet was produced in the same manner as the above-mentioned negative electrode sheet. The same positive electrode sheet was used in all the batteries of Examples and Comparative Examples.

3) Preparation of Non-Aqueous Electrolytes Non-aqueous electrolytes used in the batteries of Examples 1 to 14 and Comparative Examples 1 to 14 were prepared as follows. Propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC) are mixed so as to have a non-aqueous solvent composition shown in Table 1 and Table 2 to prepare a non-aqueous solvent. did. LiPF ₆ as an electrolyte salt was added to this non-aqueous solvent,
A non-aqueous electrolyte was prepared by adding the non-aqueous solvent to a concentration of 1.0 mol / l with respect to the volume thereof. Further, tetraethylammonium fluoride-tetrakis (hydrofluoride) [(C ₂ H ₅ ) ₄ as an additive is added to this non-aqueous electrolyte.
NF.4HF] was added in the amount shown in Table 1.

The non-aqueous electrolyte used in the batteries of Examples 15 and 16 was ethylene carbonate (EC).
And diethyl carbonate (DEC) in a volume ratio of 30: 7
It was prepared by adding LiPF ₆ as an electrolyte salt to the non-aqueous solvent mixed at 0 so as to have a concentration of 1.0 mol / l with respect to the volume of the non-aqueous solvent. Then, as an additive in Example _{15 [(CH 3) 4 NF} · 4HF] was added 1% by weight based on the weight of the non-aqueous electrolyte, _[as an additive in Example _{16 (C 2 H 5) 3} N · 4HF] was added in an amount of 1% by weight based on the weight of the non-aqueous electrolyte.

In Tables 1 and 2, the non-aqueous solvent composition is the volume ratio of PC, EC, DEC, and EMC (vo.
The additive amount is expressed as a ratio of the weight of the additive to the weight of the non-aqueous electrolyte (wt%, that is, wt%, and the weight of the non-aqueous electrolyte is 100 wt%).
It is represented by.

4) Preparation of Battery Using a polyethylene microporous membrane as a separator, a positive electrode sheet, a separator, a negative electrode sheet and a separator were laminated in this order and wound to produce a power generating element. This power generating element was housed in a battery case made of aluminum, and the nonaqueous electrolyte prepared in 3) above was vacuum-injected into the battery case. Then, the battery case was sealed and the battery was assembled by a known method.

2. Measurement Examples 1 to 16 and Comparative Examples 1 to 1 produced by the above method
The following measurements were performed on the battery of No. 4.

1) Charge / Discharge Cycle Test In the charge / discharge cycle test, the following measurements were performed in an atmosphere of 25 ° C. First, after charging to a constant voltage of 360 mA to 4.2 V, charging was performed for 3 hours at a constant voltage of 4.2 V. Then, the battery was left for 10 minutes. After standing, this battery was discharged to 2.75 V at a constant current of 360 mA, and then left for 10 minutes again. This is one cycle and 3
00 cycles of charging and discharging were performed. The discharge capacities of the 1st cycle and the 300th cycle of this battery were measured, and the ratio of the discharge capacity of the 300th cycle to the 1st cycle was calculated by the following formula to obtain the capacity retention rate. [Capacity retention rate] = [Discharge capacity at the 300th cycle] /
[First cycle discharge capacity] × 100

2) Low Temperature Discharge Test In the low temperature discharge test, the room temperature discharge capacity was first measured in the following atmosphere at 25 ° C. After charging to a constant current of 360 mA to 4.2 V, charging was performed at a constant voltage of 4.2 V for 3 hours. Then, this battery was left for 5 hours. After standing, the battery was discharged at a constant current of 360 mA to 2.75 V, and the discharge capacity was measured and set as the room temperature discharge capacity.

Next, the low temperature discharge capacity was measured. 25
In an atmosphere of ° C, the battery was charged with a constant current of 360 mA to 4.2 V and then charged with a constant voltage of 4.2 V for 3 hours. afterwards,
This battery was left for 5 hours in an atmosphere of 0 ° C. After leaving
This battery was discharged to 2.75 V at a constant current of 360 mA in the same atmosphere at 0 ° C., and the discharge capacity was measured and set as the low temperature discharge capacity.

The ratio of the low temperature discharge capacity to the room temperature discharge capacity of this battery was calculated by the following formula and used as the low temperature discharge capacity ratio. [Low temperature discharge capacity ratio] = [Low temperature discharge capacity] / [Normal temperature discharge capacity] × 100

3. Results and Discussion Tables 1 and 2 show the measurement results of the capacity retention rate and the low temperature discharge capacity ratio. Non-aqueous solvent of batteries in Examples 1 to 6 and Comparative Examples 1 to 7 using graphite as the negative electrode active material and ethylene carbonate (EC) and chain carbonate diethyl carbonate (DEC) as the non-aqueous solvent. The relationship between the volume ratio of ethylene carbonate and the capacity retention rate is shown in FIG. 1, and the relationship between the volume ratio of ethylene carbonate in the non-aqueous solvent and the low temperature discharge capacity ratio is shown in FIG.
reference).

1 and 2, tetraethylammonium fluoride-tetrakis (hydrofluoride) [(C ₂ H
₅₎ shows a 4 _NF · 4HF] (in the case of additives) is contained 1 wt% in the non-aqueous electrolyte measurements by a solid line shows the measurement result when the additive is not contained by a broken line.

As shown in FIGS. 1 and 2, in the batteries (Comparative Examples 1 to 3 and Comparative Example 7) in which the volume ratio of ethylene carbonate in the non-aqueous solvent was 10% by volume and 60% by volume, the addition was not performed. Even when the agent was added to the non-aqueous electrolyte, the capacity retention and the low temperature discharge capacity ratio were slightly improved. However, a battery in which the volume ratio of ethylene carbonate in the non-aqueous solvent is 20% to 50% by volume (Examples 1 to 1)
6. In Comparative Examples 4 to 6), it was found that the addition of the additive to the non-aqueous electrolyte significantly improved the capacity retention rate and the low temperature discharge capacity ratio.

As described above, in a battery in which the volume ratio of ethylene carbonate in the non-aqueous solvent is 20% to 50% by volume, the lithium ion conductivity of the film formed on the surface of the negative electrode active material is increased by the above additives. It is considered that the cycle life characteristics and the low temperature discharge characteristics are improved due to the high value.

Next, (C ₂ H ₅ ) ₄ for the non-aqueous electrolyte
The relationship between the amount of NF.4HF (additive) added and the capacity retention is shown in FIG. 3, and the relationship between the amount of additive added to the non-aqueous electrolyte and the low temperature discharge capacity ratio is shown in FIG. In FIGS. 3 and 4, Example 3 and Examples 7 to 7 each including the non-aqueous electrolyte containing 30% by volume of EC and 70% by volume of DEC as the non-aqueous solvent.
12 shows the measurement results of the batteries in Comparative Example 12, Comparative Example 5, Comparative Example 8, and Comparative Example 9 (see Table 2). In addition, in Table 2, for comparison, Example 3 and Comparative Example 5 are duplicated. As shown in FIG. 3 and FIG. 4, batteries in which the amount of the additive added to the non-aqueous electrolyte was less than 0.1% by weight and more than 2.0% by weight (Comparative Example 5, Comparative Example 8, and Comparative Example 9) ), The capacity retention rate and the low temperature discharge capacity ratio of both the batteries (Example 3 and Examples 7 to 12) of 0.1 wt% or more and 2.0 wt% or less were improved.

Next, ethylene carbonate was added to the non-aqueous electrolyte, and chain carbonates such as diethyl carbonate (DEC) and ethyl methyl carbonate (EMC) were added.
The capacity retention rate and the low temperature discharge capacity ratio of the batteries in Examples 3, 13 and 14 containing C are examined (see Table 2). The battery of Example 13 containing DEC and EMC had good capacity retention and low temperature discharge capacity ratio.

Further, in the batteries of Examples 15 and 16 which differ from Example 3 only in the kind of additive such as hydrogen fluoride salt of quaternary ammonium fluoride, the capacity retention rate is shown in Table 1. Also, the low temperature discharge capacity ratio was almost the same value as that of the example. Thus, it was shown that the capacity retention rate and the low temperature discharge capacity ratio were improved regardless of the type of quaternary ammonium fluoride.

In Comparative Example 10 and Comparative Example 11 in which metallic lithium was used as the negative electrode active material and propylene carbonate (PC) was used as the non-aqueous electrolyte, the capacity retention rates were as low as 3% and 20%, respectively. Comparative Example 1 using metal lithium as a negative electrode active material and a non-aqueous solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a volume ratio of 30:70 as a non-aqueous electrolyte.
The capacity retention of the battery of No. 4 showed a low value of 20%, and it was confirmed that the cycle life characteristics were insufficient (see Table 2). As described above, when metallic lithium is used as the negative electrode active material, even if the additive is added to the non-aqueous electrolyte, it can be used for a relatively long period of 300 cycles.
It is considered that this is because the generation of dendrites cannot be suppressed sufficiently.

Further, graphite was used as the negative electrode active material and PC
The batteries of Comparative Example 12 and Comparative Example 13 using as a non-aqueous solvent could not be discharged. Even when the above additives are added to the non-aqueous electrolyte, using graphite as the negative electrode active material, when using propylene carbonate in the non-aqueous electrolyte, it is considered that the decomposition of the non-aqueous electrolyte can not be suppressed. To be

As is clear from the above results, graphite was used as the negative electrode active material of the non-aqueous electrolyte secondary battery, and a mixture of ethylene carbonate and chain carbonate was used as the non-aqueous electrolyte. The ratio of the volume of ethylene carbonate to the total volume of the chain carbonate is 20% by volume to 50% by volume, and
Tetraethylammonium fluoride - tetrakis _{(Hidorofurorido)} by adding 0.1 wt% to 2.0 wt% with respect to _{[(C 2 H 5) 4} NF · 4HF] The non-aqueous electrolyte, low-temperature discharge characteristic and cycle life The characteristics could be improved. Furthermore, tetraethylammonium fluoride - tetrakis _{(Hidorofurorido) [(C 2 H 5)} 4 N
In the case of adding a compound represented by the general formula (4), the general formula (5), or the general formula (6) other than F.4HF], similarly, good life characteristics and low temperature characteristics are obtained. I was able to. By using a mixture of diethyl carbonate and ethyl methyl carbonate as the chain carbonate, the low temperature discharge characteristics and cycle life characteristics of the non-aqueous electrolyte secondary battery could be further improved.

[0049]

According to the present invention, it is possible to provide a non-aqueous electrolyte secondary battery having excellent low temperature discharge characteristics and cycle life characteristics.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the volume ratio of ethylene carbonate in a non-aqueous solvent and the capacity retention rate.

FIG. 2 is a graph showing the relationship between the volume ratio of ethylene carbonate in a non-aqueous solvent and the low temperature discharge capacity ratio.

FIG. 3: Tetraethylammonium fluoride-tetrakis (hydrofluoride) [(C
₂ H ₅ ) ₄ NF · 4 HF] added amount and capacity retention graph

FIG. 4 Tetraethylammonium fluoride-tetrakis (hydrofluoride) [(C
₂ H ₅ ) ₄ NF · 4 HF] addition amount and discharge capacity

Claims (2)

[Claims] 1. A negative electrode containing a carbonaceous material, and a positive electrode,
A non-aqueous electrolyte secondary battery comprising a non-aqueous electrolyte, wherein the non-aqueous electrolyte contains ethylene carbonate and a chain carbonate, and the volume ratio of ethylene carbonate to the total volume of ethylene carbonate and the chain carbonate is 20% by volume. ˜50% by volume, and at least one compound represented by the following general formula (1), general formula (2), or general formula (3) is 0.1 wt% to 2 wt% with respect to the non-aqueous electrolyte. % Non-aqueous electrolyte secondary battery characterized by being added. [Chemical 1] (Wherein, R1 and R2 are the general formula _{(C n H 2n + 1)} carbon number n represented by is in the range of 1 to 4 alkyl groups, coefficient of hydrogen fluoride and m is in the range of 1-6 ) [Chemical 2] (In the formula, R3 and R4 are alkyl groups represented by the general formula (C _n H _{2n + 1} ) and having a carbon number n in the range of 1 to 4, and the coefficient m of hydrogen fluoride is in the range of 1 to 6. ) [Chemical 3] (Wherein, R5 is a general formula _{(C n H 2n + 1)} with an alkyl group carbon number n is in the range of 1 to 4 represented, the coefficient of hydrogen fluoride and m is in the range of 1 to 6) 2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the chain carbonate is a mixture of diethyl carbonate and ethylmethyl carbonate.