JP7213221B2 - Non-aqueous electrolyte secondary battery - Google Patents

Description

The present technology relates to non-aqueous electrolyte secondary batteries.

Japanese Patent Laying-Open No. 7-245121 (Patent Document 1) discloses a negative electrode made of pure lithium.

JP-A-7-245121

Lithium ion secondary batteries are widespread. In a lithium ion secondary battery, a material capable of reversibly absorbing lithium (Li) ions (for example, graphite) is used as a negative electrode active material.

In non-aqueous electrolyte secondary batteries (which may be abbreviated as “batteries” hereinafter), the use of Li metal itself as a negative electrode active material has also been investigated. By utilizing the dissolution reaction and deposition reaction of Li metal, it is expected that the capacity of the battery will be increased.

However, Li metal has room for improvement in cycle characteristics. That is, Li metal can form dendrites during charging (during precipitation reaction). Due to the growth of dendrites each time charging is performed, capacity deterioration tends to progress rapidly.

An object of the present technology is to improve cycle characteristics in a battery containing Li metal as a negative electrode active material.

The configuration and effects of the present technology will be described below. However, the mechanism of action of this technology includes presumption. Whether the mechanism of action is correct or not does not limit the scope of the present technology.

[1] A non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The negative electrode contains a negative electrode active material. The negative electrode active material contains lithium metal. The electrolytic solution contains a solvent, a supporting electrolyte and an anionic surfactant. Anionic surfactants include at least one selected from the group consisting of sulfonates, sulfates and phosphates.

In the battery of the present technology, the electrolyte contains an anionic surfactant. Anionic surfactants include at least one selected from the group consisting of sulfonates, sulfates and phosphates. Hereinafter, the anionic surfactant of the present technology is also referred to as "specific surfactant".

During charging, the electrolyte is reductively decomposed on the Li metal surface. Decomposition products of the electrolyte can form a film on the surface of the Li metal. The film is called an SEI (solid electrolyte interface) film. Formation of the SEI film can reduce the active sites on the surface of the Li metal.

However, the SEI film is not formed on the Li metal newly deposited during charging (that is, on the new surface). It is believed that the new surface contains more active sites than the Li metal coated with the SEI film. Therefore, it is considered that precipitation of Li metal concentrates on the new surface and dendrites grow.

Conventionally, additives have been proposed that promote the formation of SEI films. For example, additives such as vinylene carbonate (VC) and monofluoroethylene carbonate (FEC) are added to the electrolyte. However, it is considered difficult to sufficiently inhibit dendrite growth by VC, FEC, and the like. This is probably because the deposition rate of Li metal is higher than the formation rate of the SEI film.

The specific surfactant of the present technology can quickly adsorb to the surface of Li metal during deposition of Li metal. Adsorption of the specific surfactant is expected to reduce the number of active sites on the nascent surface. Therefore, it is expected that dendrite growth is inhibited and cycle characteristics are improved.

Although the details of the mechanism are unknown, when a cationic surfactant is used instead of the specific surfactant (anionic surfactant), there is a tendency that the cycle characteristics are not improved.

[2] The sulfonate has, for example, the formula (I):
_CH3 ^{( CR3R2R1} )( ^CH2 ) _{n1SO3 - .M1} ^{( I} )
may be represented by
Sulfates are for example of the formula (II):
_CH3 ^{( CR6R5R4} )( _CH2 ) ^n2SO4 _{- .M2} ^{( II} )
may be represented by
The phosphate is for example of formula (III):
_CH3 ( ^CR11R10R9 )( _CH2 ) _n3 ^{( PO4R8R7} ) ₂ ^{- .xM3 ( III} )
may be represented by
^In formulas (I) to ^{( III} ), " ^R1 , ^R2 , R3, ^R4 , R5, ^R6 , ^R7 , R8, ^R9 , ^R10 and ^R11 " are each independently , hydrogen atom, methyl group, ethyl group, hydroxyethyl group, carbonyl group or aminomethyl group. "n1, n2 and n3" each independently represent an integer of 1 to 20; “M ¹ , M ² and M ³ ” each independently represent an alkali metal ion. "x" represents an integer of 1 or 2;

[3] The anionic surfactant may have a mass fraction of, for example, 1% to 3% with respect to the electrolyte.

[4] The negative electrode active material may consist essentially of lithium metal, for example.

FIG. 1 is a schematic diagram showing an example of a non-aqueous electrolyte secondary battery in this embodiment. FIG. 2 is a schematic diagram showing an example of the electrode body in this embodiment.

Hereinafter, embodiments of the present technology (hereinafter also referred to as “present embodiments”) will be described. However, the following description does not limit the scope of this technology.

As used herein, "comprise, include," "have," and variations thereof [e.g., "be composed of," "emcopass, involve," Descriptions of "contain", "carry, support", "hold", etc.] are open-ended. That is, it includes a configuration, but is not limited to including only that configuration. References to "consist of" are closed form. The statement "consisting essentially of" is semi-closed form. That is, the description “consisting essentially of” indicates that additional components may be included in addition to the essential components within a range that does not hinder the purpose of the present technology. For example, components normally assumed in the field to which the present technology belongs (for example, unavoidable impurities, etc.) may be included as additional components.

In this specification, singular forms (“a,” “an,” and “the”) include plural forms unless otherwise stated. For example, "particle" can include not only "one particle" but also "aggregate of particles (powder)".

In the present specification, numerical ranges such as "1% to 3%" include upper and lower limits unless otherwise specified. For example, "1% to 3%" indicates a numerical range of "1% or more and 3% or less". Also, numerical values arbitrarily selected from within the numerical range may be used as the new upper and lower limits. For example, a new numerical range may be set by arbitrarily combining the numerical values within the numerical range and the numerical values described elsewhere in this specification.

In this specification, when a compound is represented by a stoichiometric composition formula such as "LiCoO ₂ ", the stoichiometric composition formula is merely a representative example. Composition ratios may be non-stoichiometric. For example, when lithium cobalt oxide is expressed as “LiCoO ₂ ”, the composition ratio of lithium cobalt oxide is not limited to “Li/Co/O=1/1/2” unless otherwise specified. It may contain Li, Co and O in a compositional ratio.

The dimensional relationships in each drawing may not match the actual dimensional relationships. Dimensional relationships (length, width, thickness, etc.) in each figure may be changed to facilitate understanding of the present technology. Furthermore, some configurations may be omitted.

<Non-aqueous electrolyte secondary battery>
FIG. 1 is a schematic diagram showing an example of a non-aqueous electrolyte secondary battery in this embodiment.
Battery 100 can be used in any application. Battery 100 may be used, for example, in an electric vehicle as a main power source or power assist power source. A battery module or an assembled battery may be formed by connecting a plurality of batteries 100 .

Battery 100 includes an exterior body 90 . The exterior body 90 is rectangular (flat rectangular parallelepiped). However, the rectangular shape is an example. The exterior body 90 may be, for example, cylindrical or pouch-shaped. The exterior body 90 may be made of an Al (aluminum) alloy, for example. The exterior body 90 houses the electrode body 50 and an electrolytic solution (not shown). The electrode assembly 50 is connected to a positive electrode terminal 91 by a positive current collecting member 81 . The electrode body 50 is connected to the negative terminal 92 by the negative collector 82 .

FIG. 2 is a schematic diagram showing an example of the electrode body in this embodiment.
The electrode body 50 is of a wound type. Electrode body 50 includes positive electrode 10 , separator 30 and negative electrode 20 . That is, the battery 100 includes a positive electrode 10, a negative electrode 20, and an electrolytic solution. The positive electrode 10, the separator 30 and the negative electrode 20 are all belt-shaped sheets. The electrode assembly 50 may include multiple separators 30 . The electrode body 50 is formed by laminating the positive electrode 10, the separator 30 and the negative electrode 20 in this order and winding them in a spiral shape. Either the positive electrode 10 or the negative electrode 20 may be sandwiched between the separators 30 . Both the positive electrode 10 and the negative electrode 20 may be sandwiched between separators 30 . The electrode body 50 is formed flat after being wound. Note that the winding type is an example. The electrode body 50 may be, for example, a stacked type.

《Electrolyte》
At least part of the electrolytic solution is impregnated into the electrode assembly 50 . The electrode body 50 may be impregnated with the entire electrolytic solution. Part of the electrolytic solution may be impregnated into the electrode assembly 50 . A part of the electrolytic solution may be stored, for example, outside the electrode body 50 (bottom portion of the exterior body 90).

The electrolyte is a liquid electrolyte. The electrolytic solution of this embodiment contains a solvent, a supporting electrolyte, and a specific surfactant. The electrolytic solution may further contain optional additives in addition to these components.

(solvent)
Solvents are aprotic. The solvent can contain any component. Solvents include, for example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), 1,2-dimethoxyethane (DME ), methyl formate (MF), methyl acetate (MA), methyl propionate (MP), and γ-butyrolactone (GBL).

(supporting electrolyte)
The supporting electrolyte is dissolved in the solvent. The supporting electrolyte may contain, for example, at least one selected from the group consisting of LiPF ₆ , LiBF ₄ and LiN(FSO ₂ ) ₂ . The supporting electrolyte may have a molarity of, for example, 0.5 mol/L to 2.0 mol/L. The supporting electrolyte may have a molarity of, for example, 0.8 mol/L to 1.2 mol/L.

(Specific surfactant)
The electrolytic solution contains a specific surfactant. The electrolytic solution may contain, for example, 0.1% to 5% of specific surfactant in terms of mass fraction (mass concentration). The electrolytic solution may contain, for example, 1% to 3% by mass fraction of a specific surfactant. When the electrolytic solution contains a plurality of specific surfactants, the mass fraction of the specific surfactant indicates the total mass fraction of each specific surfactant.

The specific surfactant may be dissolved in the solvent or dispersed in the solvent. The specific surfactant can quickly adsorb to the surface of Li metal during deposition of Li metal. Adsorption of the specific surfactant is expected to reduce the number of active sites on the nascent surface. Therefore, it is expected that dendrite growth is inhibited and cycle characteristics are improved.

A specific surfactant is an anionic surfactant. The specific surfactant contains at least one selected from the group consisting of sulfonates, sulfates and phosphates. The specific surfactant may be any one of sulfonate, sulfate or phosphate. The specific surfactant may be a mixture of any one or more of sulfonates, sulfates and phosphates. The specific surfactant may contain at least one selected from the group consisting of a sulfonic acid group, a sulfate group and a phosphate group in one molecular chain. The specific surfactant may be, for example, a homopolymer or a copolymer. A specific surfactant may be, for example, an oligomer or a polymer.

Sulfonates are for example of the formula (I):
_CH3 ^{( CR3R2R1} )( ^CH2 ) _{n1SO3 - .M1} ^{( I} )
may be represented by

In formula (I), "R ¹ , R ² and R ³ " are each independently a hydrogen atom (--H), a methyl group (--CH ₃ ), an ethyl group (--C ₂ H ₅ ), a hydroxyethyl group (--C ₂ H ₄ OH), carbonyl group (--C(=O)--) or aminomethyl group (--CH ₂ NH ₂ ). “n1” represents an integer from 1 to 20; “M ¹ ” represents an alkali metal ion.

"n1" may represent an integer from 5 to 15, for example. "n1" may represent an integer from 5 to 10, for example. "M ¹ " may contain at least one selected from the group consisting of Na ⁺ , Li ⁺ and K ⁺ , for example.

Sulfates are for example of the formula (II):
_CH3 ^{( CR6R5R4} )( _CH2 ) ^n2SO4 _{- .M2} ^{( II} )
may be represented by

In formula (II), "R ⁴ , R ⁵ and R ^{6 "} each independently represent a hydrogen atom, a methyl group, an ethyl group, a hydroxyethyl group, a carbonyl group or an aminomethyl group. "n2" represents an integer from 1 to 20; " ^M2 " indicates an alkali metal ion.

"n2" may represent an integer from 5 to 15, for example. "n2" may represent an integer from 5 to 10, for example. "M ² " may contain at least one selected from the group consisting of Na ⁺ , Li ⁺ and K ⁺ , for example.

The phosphate is for example of formula (III):
_CH3 ( ^CR11R10R9 )( _CH2 ) _n3 ^{( PO4R8R7} ) ₂ ^{- .xM3 ( III} )
may be represented by

^In formula (III), " ^R7 , R8, ^R9 , ^R10 and ^R11 " each independently represents a hydrogen atom, a methyl group, an ethyl group, a hydroxyethyl group, a carbonyl group or an aminomethyl group. “n3” represents an integer from 1 to 20; " ^M3 _" represents an alkali metal ion. "x" represents an integer of 1 or 2;

"n3" may indicate an integer from 5 to 15, for example. "n3" may represent an integer from 8 to 12, for example. "M ³ " may contain at least one selected from the group consisting of Na ⁺ , Li ⁺ and K ⁺ , for example.

The specific surfactant may contain, for example, at least one selected from the group consisting of sodium 1-decanesulfonate, sodium decyl sulfate, monododecyl monosodium phosphate, and monododecyl disodium phosphate.

Specific surfactants may have a number average molecular weight (Mn) of, for example, 250 to 7,000. Specific surfactants may have a weight average molecular weight (Mw) of, for example, 300 to 9000. Number average molecular weight (Mn) and weight average molecular weight (Mw) can be measured by the GPC method (gel permeation chromatography).

《Negative electrode》
The negative electrode 20 contains a negative electrode active material. The negative electrode 20 may, for example, consist essentially of a negative electrode active material. The negative electrode active material contains Li metal. The negative electrode active material may, for example, consist essentially of Li metal. The negative electrode active material may further contain other components as long as it contains Li metal. The negative electrode active material may contain, for example, a Li alloy in addition to the Li metal. The Li alloy may contain, for example, at least one selected from the group consisting of Si (silicon), Sn (tin), Al, Cd (cadmium), Sb (antimony) and Pb (lead). The negative electrode active material contains, in addition to Li metal, at least one selected from the group consisting of graphite, soft carbon, hard carbon, SiO, Si/C composite materials, SnO, and Li ₄ Ti ₅ O ₁₂ . You can "Si/C composite material" indicates a composite material of silicon and carbon. A Si/C composite material can be formed, for example, by supporting Si metal, Si oxide, or the like on a carbon material (graphite, amorphous carbon, or the like).

Li metal consists essentially of Li alone. The Li metal may be in the form of foil, for example. For example, a Li foil may form the negative electrode 20 . The Li foil may have a thickness of, for example, 0.1 mm to 2 mm. The Li foil may have a thickness of, for example, 0.1 mm to 1 mm. The Li foil may be carried on the negative electrode substrate. The negative electrode base material may contain, for example, a Cu (copper) plate, a Cu foil, or the like. For example, the negative electrode 20 may be formed by crimping a Li foil to one side of a Cu plate. The negative electrode 20 may be formed by crimping Li foil on both sides of the Cu plate. The Li metal may, for example, be reticulated. The Li metal may be particulate, for example. For example, the negative electrode 20 may be formed by layering a mixture containing Li metal particles, carbon particles, and the like.

The negative electrode 20 may include a support layer that supports Li metal, for example. The carrier layer may be formed on the surface of the negative electrode substrate. The carrier layer may contain, for example, a carbon-based negative electrode active material (such as graphite) and a binder. The carrier layer may contain, for example, a carbon-based negative electrode active material, an alloy-based negative electrode active material (Si metal, Si oxide, etc.), and a binder. Binders may include, for example, styrene-butadiene rubber (SBR), carboxymethylcellulose (CMC), and the like. For example, a Li foil may be arranged on the surface of the carrier layer. For example, a Li foil may be laminated on the surface of the carrier layer. For example, Li metal particles may be arranged on the surface of the support layer. For example, Li metal particles may be embedded in the surface of the support layer. For example, a Li metal powder layer may be formed on the surface of the carrier layer.

《Positive electrode》
The positive electrode 10 includes, for example, a positive electrode mixture layer. Positive electrode 10 may further include, for example, a positive electrode substrate. For example, a positive electrode mixture layer may be arranged on the surface of the positive electrode substrate. The positive electrode mixture layer may be arranged only on one side of the positive electrode substrate. The positive electrode mixture layer may be arranged on both the front and back surfaces of the positive electrode substrate. The positive electrode substrate is a conductive sheet. The positive electrode base material may contain, for example, Al foil or the like. The cathode substrate may have a thickness of, for example, 10 μm to 30 μm.

The positive electrode composite layer may have a thickness of, for example, 10 μm to 100 μm. The positive electrode mixture layer may contain a positive electrode active material, a conductive material, and a binder. The positive electrode mixture layer may be, for example, substantially composed of a positive electrode active material, a conductive material, and a binder. The positive electrode mixture layer is composed of, for example, a positive electrode active material of 80% to 99.8% by mass, a conductive material of 0.1% to 10%, and a binder of 0.1% to 10%. may

The positive electrode active material can contain any component. The positive electrode active material contains at least one selected from the group consisting of LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , Li(NiCoMn)O ₂ , Li(NiCoAl)O ₂ and LiFePO ₄ , for example. You can Here, for example, descriptions such as “(NiCoMn)” in composition formulas such as “Li(NiCoMn)O ₂ ” indicate that the sum of the composition ratios in parentheses is one. The conductive material can contain any component. The conductive material may contain, for example, acetylene black. The binder can contain optional ingredients. The binder may include, for example, polyvinylidene fluoride (PVdF).

《Separator》
At least part of the separator 30 is interposed between the positive electrode 10 and the negative electrode 20 . The separator 30 separates the positive electrode 10 and the negative electrode 20 . Separator 30 may have a thickness of, for example, 10 μm to 30 μm.

Separator 30 is porous. The separator 30 is permeable to the electrolyte. The separator 30 may have an air permeability of, for example, 200s/100ml to 400s/100ml. "Air permeability" in this specification indicates "air resistance" defined in "JIS P8117:2009". Air permeability is measured by the Gurley test method.

Separator 30 is electrically insulating. The separator 30 may contain, for example, polyolefin resin. The separator 30 may be substantially made of polyolefin resin, for example. The polyolefin-based resin may contain, for example, at least one selected from the group consisting of polyethylene (PE) and polypropylene (PP). The separator 30 may have, for example, a single layer structure. The separator 30 may, for example, consist essentially of a PE layer. The separator 30 may have a multilayer structure, for example. The separator 30 may be formed, for example, by laminating a PP layer, a PE layer and a PP layer in this order. For example, a heat-resistant layer or the like may be formed on the surface of the separator 30 .

Hereinafter, an embodiment of the present technology (hereinafter also referred to as "this embodiment") will be described. However, the following description does not limit the scope of this technology.

<Production of non-aqueous electrolyte secondary battery>
No. as follows. 1 to No. An evaluation battery (non-aqueous electrolyte secondary battery) according to No. 13 was manufactured.

(Preparation of positive electrode)
The following materials were prepared.
Positive electrode active material: Li(Ni1 _/ 3Co1 _/ 3Mn1 _/3 ) _O2
Conductive material: Acetylene black Binder: PVdF
Dispersion medium: N-methyl-2-pyrrolidone Positive electrode substrate: Al foil

A positive electrode mixture slurry was prepared by mixing the positive electrode active material, the conductive material, the binder, and the dispersion medium. The mass ratio of the solid content was "positive electrode active material/conductive material/binder=87/10/3". A positive electrode mixture layer was formed by applying the positive electrode mixture slurry to the surface of the positive electrode substrate. The positive electrode mixture layer was compressed. A positive electrode was prepared as described above.

(Preparation of negative electrode)
The following materials were prepared.
Negative electrode active material: Li metal (Li foil, thickness = 0.5 mm)
Negative electrode base material: Cu plate (thickness = 1 mm)

A Li foil was crimped to the Cu plate. This prepared the negative electrode.

(Electrolyte)
An electrolyte was prepared. The electrolyte contained the following components. Additive types and mass fractions are shown in Table 1.

Solvent: "EC/EMC = 3/7 (volume ratio)"
Supporting electrolyte: LiPF ₆ (molarity = 1.0 mol/L)
Additives: See Table 1.

(assembly)
A separator was prepared. The separator had a three-layer structure. The three-layer structure consisted of a PP layer, a PE layer and a PP layer. The separator had an air permeability of 300s/100mL.

A positive electrode, a separator, and a negative electrode were laminated such that the positive electrode and the negative electrode faced each other with the separator interposed therebetween. An electrode body was thus formed. A shell was prepared. The package was a pouch made of Al laminated film. The electrode body was housed in the exterior body. An electrolytic solution was injected into the exterior body. The outer body was sealed. An evaluation battery was assembled as described above.

(activation treatment)
The evaluation battery was charged to 4.1 V by constant current charging at 0.3 It in a constant temperature bath set at 25°C. The evaluation cell was then discharged to 3V by constant current discharge of 0.3It. The cycle of charging and discharging was repeated three times. Note that "It" is a symbol representing the time rate of current. A current of 1 It is defined such that the design capacity of the evaluated battery is discharged in 1 hour.

(Measurement of initial capacity)
After the activation process, the evaluation battery was fully charged by constant current-constant voltage charging. The current during constant current charging was 0.2 It. The voltage during constant voltage charging was 4.1V. Constant voltage charging was terminated when the current decayed to 0.02 It. Then, the evaluation battery was discharged to 3.0 V by constant current discharge of 0.3 It, and the initial capacity (discharge capacity) was measured.

<Cycle test>
The charge/discharge cycle was repeated 100 times in a constant temperature bath set at 25°C. One cycle indicates the following cycle of "charging→first rest→discharging→second rest". The discharge capacities at the 1st cycle, the 50th cycle and the 100th cycle were measured.

Charging: constant current method, current = 0.5 It, final voltage = 4.1 V
First rest: 10 minutes Discharge: constant current method, current = 0.5 It, end voltage = 3.0 V
Second pause: 10 minutes

<Results>
No. In 1, the electrolyte does not contain additives. No. In 1, progress of capacity deterioration is rapid.

No. 2 and no. In 3, the electrolyte contains VC. VC is believed to promote the formation of the SEI film. As the mass fraction of VC increases, the cycle characteristics tend to improve, albeit slightly.

No. 4 and no. In 5, the electrolyte contains FEC. FEC is believed to promote the formation of the SEI film. Addition of FEC tends to improve cycle characteristics to some extent.

No. 6 to No. In 11, the electrolyte contains surfactant A, B or C. No. 6 to No. In No. 11, there is a tendency for the cycle characteristics to significantly improve. This is probably because the surfactant can quickly adsorb to the surface of the Li metal when the Li metal is deposited. Surfactants A, B and C are all anionic.

No. In Nos. 12 and Nos. 13, the electrolyte contains surfactant D. No. 12 and no. In No. 13, progress of capacity deterioration is rapid. Surfactant D is cationic.

This embodiment and this example are illustrative in all respects. This embodiment and this example are not restrictive. The scope of the present technology includes all changes within the meaning and range of equivalence to the description of the claims. For example, it is planned from the beginning that arbitrary configurations are extracted from this embodiment and this example and they are arbitrarily combined. When a plurality of actions and effects are described in this embodiment and this example, the scope of the present technology is not limited to the range in which all the actions and effects are exhibited.

10 positive electrode, 20 negative electrode, 30 separator, 50 electrode body, 81 positive electrode current collecting member, 82 negative electrode current collecting member, 90 exterior body, 91 positive electrode terminal, 92 negative electrode terminal, 100 battery (non-aqueous electrolyte secondary battery).

Claims (3)

including a positive electrode, a negative electrode and an electrolyte;
The negative electrode includes a negative electrode active material,
the negative electrode active material includes lithium metal,
The electrolytic solution contains a solvent, a supporting electrolyte and an anionic surfactant,
The anionic surfactant contains at least one selected from the group consisting of sulfonates, sulfates and phosphates,
Said sulfonate has the formula (I):
CH3 ( CR3R2R1 ) ( ^CH2 ) n1SO3 _{- .M1} ( ^{I )} _{_} ^_ _{_} _ ^_
is represented by
Said sulfate salt has the formula (II):
CH3 ( ^CR6R5R4 ) ( _CH2 ) n2SO4 ^- .M2 ^{( II} ) _{_} ^_ _{_} _ _{_}
is represented by
Said phosphate has the formula (III):
CH3 ( ^CR11R10R9 ) ⁽ CH2 ) _n3 ( PO4R8R7 ) ₂ ^- .xM3 ^{( III} ) _{_} ^_ _ ^_ _{_} _
is represented by
In the above formulas (I) to (III),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each independently a hydrogen atom, a methyl group, an ethyl group, a hydroxyethyl group; , represents a carbonyl group or an aminomethyl group,
n1, n2 and n3 each independently represent an integer from 1 to 20,
M ¹ , M ² and M ³ each independently represent an alkali metal ion,
x represents an integer of 1 or 2;
Non-aqueous electrolyte secondary battery. the anionic surfactant has a mass fraction of 1% to 3% with respect to the electrolyte;
The non-aqueous electrolyte secondary battery according to claim 1 . wherein the negative electrode active material consists essentially of the lithium metal;
The non-aqueous electrolyte secondary battery according to claim 1 or 2 .

Images