Nonaqueous electrolytic solution battery, negative electrode, method for manufacturing nonaqueous electrolytic solution battery, and nonaqueous electrolytic solution

Abstract

A nonaqueous electrolytic solution battery according to the present invention is provided with a positive electrode, a negative electrode, and a nonaqueous electrolytic solution. A coating film is formed on the surface of the negative electrode. In an X-ray photoelectron spectroscopy measurement performed at a position in the coating film 10 nm, expressed as a SiO2 equivalent value, away from the surface of the negative electrode in the film thickness direction, the total value a of the atomic percentage of P, N, and S elements relative to the total atomic amount of C, O, F, P, N, and S elements contained in the coating film on the surface of the negative electrode is in the range of more than 1.0 at% to not more than 7.0 at%, and the total value b of the atomic percentage of P and N elements is not more than 0.4 at%.

Description

Non-aqueous electrolyte battery, negative electrode, method for manufacturing a non-aqueous electrolyte battery, and non-aqueous electrolyte

[0001] This invention relates to a non-aqueous electrolyte battery, a negative electrode, a method for manufacturing a non-aqueous electrolyte battery, and a non-aqueous electrolyte.

[0002] In recent years, there have been widespread attempts to improve the thermal stability of lithium secondary batteries. Patent document 1 describes how to improve the thermal stability of the charged positive electrode by incorporating a ceramic layer or a phosphate ester compound into the positive electrode active material.

[0003] Patent Document 2 describes a method of suppressing metal elution from the positive electrode and improving the thermal stability of the charged positive electrode by mixing a positive electrode active material containing tungsten with lithium fluoride and forming a lithium fluoride film on the surface of the active material. Patent Document 3 describes a method of improving the thermal stability of the charged negative electrode by adding a small amount of phosphonoformate compound to a non-aqueous electrolyte.

[0004] Patent Document 4 describes a non-aqueous electrolyte battery comprising a predetermined positive electrode containing a mixture of spinel-type lithium manganese composite oxide and lithium cobaltate, a negative electrode containing spinel-type lithium titanate, and a non-aqueous electrolyte. It states that by setting the atomic percentage of element P at a predetermined depth in the positive electrode and the atomic percentage of element P at a predetermined depth in the negative electrode within a predetermined range, gas generation is suppressed, resulting in excellent input / output performance and excellent storage performance. The document does not mention the atomic percentages of elements N or S.

[0005] Patent document 5 describes a non-aqueous electrolyte battery comprising a solute, a non-aqueous organic solvent, and a specific compound, which can exhibit excellent battery performance and suppress discoloration of the electrolyte when stored at room temperature for a long period of time. The document does not describe the atomic percentages of P, N, and S elements at a predetermined depth in the coating on the negative electrode.

[0006] Japanese Patent Publication No. 2016-33916, Japanese Patent Publication No. 2016-149242, WO2015 / 093091, WO2019 / 193756, WO2025 / 047678

[0007] Patent documents 1 to 3 describe techniques for improving the thermal stability of positive and negative electrodes in a charged state using positive electrode active materials and non-aqueous electrolytes, but there was still room for improvement in thermal stability.

[0008] Furthermore, the non-aqueous electrolyte battery described in Patent Document 4, in which the atomic percentage of element P at predetermined depths of the positive and negative electrodes is within a predetermined range, had room for improvement in thermal stability.

[0009] As a result of the inventors' research, they found that in a non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte, providing a predetermined coating on the surface of the negative electrode results in excellent thermal stability of the coating on the negative electrode when fully charged, thus completing the present invention.

[0010] The present invention aims to provide a non-aqueous electrolyte battery with excellent thermal stability of the coating on the negative electrode in a fully charged state, a negative electrode used in the non-aqueous electrolyte battery, a method for manufacturing the non-aqueous electrolyte battery, and a non-aqueous electrolyte used in the non-aqueous electrolyte battery. In other words, the present invention can be described as follows.

[0011] [1] A non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte, wherein a film is formed on the surface of the negative electrode, and SiO is formed on the film in the direction of film thickness from the surface of the negative electrode. ２ A non-aqueous electrolyte battery, wherein, in an X-ray photoelectron spectroscopy measurement at a position of 10 nm in converted value, the sum of the atomic percentages a of P, N, and S elements, based on the total atomic amounts of C, O, F, P, N, and S elements contained in the film on the negative electrode surface, is in the range of greater than 1.0 at% and less than or equal to 7.0 at%, and the sum of the atomic percentages b of P and N elements is 0.4 at% or more. [2] A non-aqueous electrolyte battery according to [1], wherein the ratio of the total value b to the total value a (b / a) is 0.5 or more and less than or equal to 1.0. [3] A non-aqueous electrolyte battery according to [1] or [2], wherein the non-aqueous electrolyte contains (I-1) a compound represented by the following general formula (1). [In general formula (1), M ａ１＋X is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and a1 represents an integer equal to the valency of the corresponding cation. a1 to d1 represent integers from 1 to 2, and a1 × b1 = c1 × d1. X is a sulfur atom or a phosphorus atom, and if X is a sulfur atom, then m is 2, and R ４ It does not exist, and when X is a phosphorus atom, m is 1. １ ~R ４ Each of these is an organic group selected independently from a fluorine atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C2-C10 alkenyl group, a C2-C10 alkenyloxy group, a C2-C10 alkynyl group, a C2-C10 alkynyloxy group, a C3-C10 cycloalkyl group, a C3-C10 cycloalkoxy group, a C3-C10 cycloalkenyl group, a C3-C10 cycloalkenyloxy group, a C6-C10 aryl group, and a C6-C10 aryloxy group, and a fluorine atom, an oxygen atom, and an unsaturated bond may be present in the organic group. [4] A non-aqueous electrolyte battery according to [3], wherein X of the compound represented by general formula (1) is a sulfur atom. [5] A non-aqueous electrolyte battery according to [4], wherein the coating contains the element S. [6] A non-aqueous electrolyte battery as described in [5], wherein SiO is present in the direction of film thickness from the negative electrode surface of the coating. ２A nonaqueous electrolyte battery, wherein in X-ray photoelectron spectroscopy measurement at a position corresponding to 10 nm in terms of SiO₂, the atomic percentage of S element based on the total atomic amount of C, O, F, P, N, and S elements contained in the coating film on the surface of the negative electrode is 0.2 at% or more. [7] The nonaqueous electrolyte battery according to any one of [1] to [6], wherein the negative electrode contains graphite. [8] The nonaqueous electrolyte battery according to any one of [1] to [7], wherein the positive electrode contains a layered rock salt type lithium transition metal composite oxide. [9] The nonaqueous electrolyte battery according to any one of [3] to [6], wherein (I-1) the compound represented by the general formula (1) has at least one P-F bond or S-F bond.

[10] The nonaqueous electrolyte battery according to any one of [3] to [6], wherein (I-1) M of the compound represented by the general formula (1) ａ１＋ contains at least one selected from the group consisting of a lithium cation, a sodium cation, a potassium cation, and a tetraalkylammonium cation.

[11] A negative electrode having a coating film provided on a surface thereof, wherein in a direction of film thickness from the surface of the negative electrode of the coating film, SiO ２ In X-ray photoelectron spectroscopy measurement at a position corresponding to 10 nm in terms of conversion, the total value a of the atomic percentages of P, N, and S elements based on the total atomic amount of C, O, F, P, N, and S elements contained in the coating film on the surface of the negative electrode is in the range of more than 1.0 at% and 7.0 at% or less, and the total value b of the atomic percentages of P and N elements is 0.4 at% or more.

[12] The negative electrode according to

[11] , wherein the ratio (b / a) of the total value b to the total value a is 0.5 or more and 1.0 or less.

[13] The negative electrode according to

[11] or

[12] , wherein the coating film contains an S element.

[14] The negative electrode according to

[13] , wherein in a direction of film thickness from the surface of the negative electrode of the coating film, SiO ２A negative electrode in which, in an X-ray photoelectron spectroscopy measurement at a position of 10 nm in converted value, the atomic percentage of element S is 0.2 at% or more, based on the total atomic amounts of elements C, O, F, P, N, and S contained in the coating on the negative electrode surface.

[15] A negative electrode according to any one of

[11] to

[14] , wherein the negative electrode contains graphite.

[16] A method for manufacturing a non-aqueous electrolyte battery comprising: a step of preparing a non-aqueous electrolyte battery comprising: a positive electrode, a negative electrode, a non-aqueous electrolyte, and (I) a non-aqueous electrolyte containing an additive compound; and a step of forming a film on the surface of the negative electrode of the non-aqueous electrolyte battery, wherein the step of forming the film comprises: a first charging step of charging to a first charging state in which the C rate is 0.05C to 0.3C and the charge state is 5% to 30% when the fully charged state is 100%, and then holding the ambient temperature at 25°C to 50°C for 4 to 72 hours; and a second charging step of charging to a second charging state in which the C rate is 0.1C to 0.5C and the charge state is 40% to 60% when the fully charged state is 100%, and then holding the ambient temperature at 45°C to 65°C for 4 to 350 hours.

[17] A method for producing a non-aqueous electrolyte battery as described in

[16] , wherein (I) the additive compound comprises (I-1) a compound represented by the following general formula (1). [In general formula (1), M ａ１＋ X is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and a1 represents an integer equal to the valency of the corresponding cation. a1 to d1 represent integers from 1 to 2, and a1 × b1 = c1 × d1. X is a sulfur atom or a phosphorus atom, and if X is a sulfur atom, then m is 2, and R ４ It does not exist, and when X is a phosphorus atom, m is 1. １ ~R ４Each of these is an organic group selected independently from a fluorine atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C2-C10 alkenyl group, a C2-C10 alkenyloxy group, a C2-C10 alkynyl group, a C2-C10 alkynyloxy group, a C3-C10 cycloalkyl group, a C3-C10 cycloalkoxy group, a C3-C10 cycloalkenyl group, a C3-C10 cycloalkenyloxy group, a C6-C10 aryl group, and a C6-C10 aryloxy group, and a fluorine atom, an oxygen atom, and an unsaturated bond may be present in the organic group.

[18]

[17] A method for producing a non-aqueous electrolyte battery according to (I-1) the compound represented by general formula (1) wherein X is a sulfur atom.

[19] A positive electrode, a negative electrode, and a non-aqueous electrolyte are provided, wherein a film is formed on the surface of the negative electrode, and SiO is present in the film thickness direction from the surface of the negative electrode. ２ In an X-ray photoelectron spectroscopy measurement at a position of 10 nm (converted value), the sum of the atomic percentages a of P, N, and S elements, based on the total atomic amounts of C, O, F, P, N, and S elements contained in the film on the negative electrode surface, is in the range of greater than 1.0 at% and less than or equal to 7.0 at%, and the sum of the atomic percentages b of P and N elements is 0.4 at% or more, wherein the non-aqueous electrolyte used in a non-aqueous electrolyte battery contains (I-1) a compound represented by the following general formula (1). [In general formula (1), M ａ１＋ X is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and a1 represents an integer equal to the valency of the corresponding cation. a1 to d1 represent integers from 1 to 2, and a1 × b1 = c1 × d1. X is a sulfur atom or a phosphorus atom, and if X is a sulfur atom, then m is 2, and R ４ It does not exist, and when X is a phosphorus atom, m is 1. １ ~R ４Each of these is an organic group independently selected from a fluorine atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C2-C10 alkenyl group, a C2-C10 alkenyloxy group, a C2-C10 alkynyl group, a C2-C10 alkynyloxy group, a C3-C10 cycloalkyl group, a C3-C10 cycloalkoxy group, a C3-C10 cycloalkenyl group, a C3-C10 cycloalkenyloxy group, a C6-C10 aryl group, and a C6-C10 aryloxy group, and a fluorine atom, oxygen atom, or unsaturated bond may also be present in the organic group.

[0012] According to the present invention, it is possible to provide a non-aqueous electrolyte battery with excellent thermal stability of the coating on the negative electrode in a fully charged state, a negative electrode used in the non-aqueous electrolyte battery, a method for manufacturing the non-aqueous electrolyte battery, and a non-aqueous electrolyte used in the non-aqueous electrolyte battery.

[0013] In this specification, "~" is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. The present disclosure will be described in detail below, but the description of the constituent elements described below is an example of an embodiment of the present disclosure and is not limited to these specific contents.

[0014] 1. Regarding non-aqueous electrolyte batteries, the non-aqueous electrolyte battery of this disclosure comprises at least a positive electrode, a coated negative electrode, and a non-aqueous electrolyte. It may also include a separator, an outer casing, etc. Alternatively, a solid electrolyte may be used as a medium for impregnating the non-aqueous electrolyte instead of a separator. Preferably, the non-aqueous electrolyte battery of this disclosure comprises at least a positive electrode, a coated negative electrode, a separator, and the non-aqueous electrolyte of this disclosure. Preferably, the non-aqueous electrolyte battery of this disclosure is a non-aqueous electrolyte secondary battery.

[0015] [Coated Negative Electrode] The negative electrode of the coated negative electrode is not particularly limited, but a material that allows for reversible insertion and removal of alkali metal ions such as lithium ions and sodium ions, or alkaline earth metal ions, may be used.

[0016] [Negative electrode active material] For example, in the case of a lithium-ion battery in which the cation is mainly lithium, the negative electrode active material constituting the negative electrode is one that can be doped and dedoped with lithium ions and contains at least one selected from the following: artificial graphite or natural graphite, carbon materials with a d value of 0.340 nm or less on the lattice plane (002) in X-ray diffraction; hard carbon, carbon materials with a d value of 0.340 nm or more on the lattice plane (002) in X-ray diffraction; lithium metal; alloys of lithium metal with other metals (for example, alloys of lithium metal with one or more metals selected from Si, Sn, and Al; alloys of lithium metal with an alloy containing one or more metals selected from Si, Sn, and Al); intermetallic compounds of lithium metal with other metals; metal oxides (for example, oxides of one or more metals selected from Si, Sn, and Al; lithium titanium oxide, etc.); metal nitrides; tin (elementary); tin compounds; activated carbon; and conductive polymers.

[0017] Furthermore, a suitable negative electrode active material can be one containing Si and / or Si metal oxide and a carbon material. The above Si is silicon metal. The Si metal oxide may also be a compound represented as SiOx (where x is a value of 0.5 to 1.5). In this case, the total content of Si and / or Si metal oxide in the negative electrode active material may be 0.1 to 50% by mass, preferably 0.1 to 30% by mass, when the total amount of the Si and / or Si metal oxide and carbon material in the negative electrode active material is taken as 100% by mass. Graphite is preferred as the carbon material, and various types of artificial graphite, natural graphite, or hard carbon (non-graphitizable carbon) can be used. Graphite exhibits very little change in its crystal structure during lithium intercalation and release, resulting in high energy density and excellent cycle characteristics. The shape of the graphite may be fibrous, spherical, granular, or flaky. Furthermore, amorphous carbon or graphite coated with amorphous carbon is preferable because it reduces the reactivity between the material surface and the electrolyte. These negative electrode active materials can be used individually or in combination of two or more.

[0018] For example, in the case of a sodium-ion battery in which the cation is mainly sodium, the negative electrode active material that constitutes the negative electrode may be sodium metal, alloys of sodium metal and other metals such as tin, intermetallic compounds of sodium metal and other metals, various carbon materials including hard carbon, metal oxides such as titanium oxide, metal nitrides, elemental tin, tin compounds, activated carbon, conductive polymers, etc. In addition to these, elemental phosphorus such as red phosphorus and black phosphorus, phosphorus compounds such as Co-P, Cu-P, Sn-P, Ge-P, and Mo-P, elemental antimony, antimony compounds such as Sb / C and Bi-Sb, etc. These negative electrode active materials may be used individually or in combination of two or more types.

[0019] [Negative Electrode Current Collector] The negative electrode has a negative electrode current collector. For example, copper, stainless steel, nickel, titanium, or alloys thereof can be used as the negative electrode current collector. In addition, aluminum or its alloys can be used in sodium-ion batteries.

[0020] [Negative electrode active material layer] The negative electrode is formed by creating a negative electrode active material layer on at least one surface of the negative electrode current collector, for example. The negative electrode active material layer is composed of, for example, the aforementioned negative electrode active material, a binder, and a conductive agent if necessary.

[0021] Examples of binders include polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, styrene-butadiene rubber (hereinafter also referred to as "SBR"), carboxymethylcellulose, methylcellulose, cellulose phthalate acetate, hydroxypropylmethylcellulose, polyvinyl alcohol, and polyimide.

[0022] Examples of conductive materials that can be used include acetylene black, Ketjen black, furnace black, carbon fiber, graphite, fluorinated graphite, and other carbon materials.

[0023] [Coating] A coating is provided on the negative electrode surface (the surface of the negative electrode active material layer). The coating is made of SiO2 in the direction of film thickness from the negative electrode surface (the surface of the negative electrode active material layer). ２In X-ray photoelectron spectroscopy measurements at a position of 10 nm (converted value), the sum of the atomic percentages a of P, N, and S elements, based on the total atomic amounts of C, O, F, P, N, and S elements contained in the coating on the negative electrode surface, is in the range of greater than 1.0 at% and less than or equal to 7.0 at%, preferably 1.1 at% to 6.0 at%, more preferably 1.1 at% to 5.7 at%, even more preferably 1.1 at% to 5.5 at%, and particularly preferably 1.1 at% to 5.0 at%. More specifically, the sum a is in the range of 1.07 at% to 7.00 at%, preferably 1.10 at% to 6.00 at%, more preferably 1.10 at% to 5.70 at%, even more preferably 1.10 at% to 5.50 at%, and particularly preferably 1.10 at% to 5.00 at%.

[0024] In the aforementioned coating, "SiO is located in the direction of film thickness from the negative electrode surface (the surface of the negative electrode active material layer)." ２ "The position at 10 nm in converted value" refers to the point where the coating is anisotropically etched and X-ray photoelectron spectroscopy measurements are performed, and when the surface of the negative electrode active material layer is reached, SiO ２ This refers to the position 10 nm back in the film thickness direction (etching direction) from the etching depth calculated using the conversion value. In other words, it is the position from the interface between the negative electrode active material layer and the coating toward the coating surface (outward). ２ This represents a position of 10 nm in terms of conversion.

[0025] Furthermore, the sum of the atomic percentages b of P and N elements, based on the total atomic amount, is 0.4 at% or more, preferably 0.5 at% or more, more preferably 0.6 at% or more, even more preferably 0.7 at% or more, and especially preferably 0.8 at% or more. The upper limit is not particularly limited, but is 10 at% or less, preferably 8 at% or less, more preferably 6 at% or less, and even more preferably 5 at% or less. More specifically, the sum b is 0.40 at% or more, preferably 0.50 at% or more, more preferably 0.60 at% or more, even more preferably 0.70 at% or more, and especially preferably 0.80 at% or more. The upper limit is not particularly limited, but is 10.00 at% or less, preferably 8.00 at% or less, more preferably 6.00 at% or less, and even more preferably 4.60 at% or less.

[0026] The non-aqueous electrolyte battery of this disclosure exhibits excellent thermal stability of the coating on the negative electrode when fully charged, and low self-discharge even when left in a high-temperature environment for a long period of time, because the sum of the atomic percentages of P, N, and S elements a and the sum of the atomic percentages of P and N elements b in the coating on the negative electrode surface are both within the above range. Furthermore, it can suppress the initial resistance of the battery and has excellent cycle characteristics, suppressing capacity degradation and resistance increase even when repeatedly charged and discharged. In other words, the non-aqueous electrolyte battery of this disclosure also excels in balancing these characteristics.

[0027] Furthermore, the ratio of the total value b to the total value a (b / a) is 0.5 or more and 1.0 or less, preferably 0.6 or more and 1.0 or less. This results in superior thermal stability of the coating on the negative electrode when fully charged. In addition, the initial resistance of the battery can be further suppressed, and the cycle characteristics are improved.

[0028] In this disclosure, the coating on the negative electrode surface preferably contains elements P and N from the viewpoint of the effects of the present invention. The coating may include cases where it does not contain element S, but it is more preferable that it contains element S from the viewpoint of the effects of the present invention. When the coating contains element S, the coating has SiO in the direction of film thickness from the negative electrode surface (the surface of the negative electrode active material layer) ２In X-ray photoelectron spectroscopy measurements at a position of 10 nm (converted value), the atomic percentage of element S is preferably 0.2 at% or more, preferably 0.3 at% or more, and preferably 0.5 at% or more, based on the total atomic amounts of elements C, O, F, P, N, and S contained in the coating on the negative electrode surface. The upper limit is not particularly limited, but is preferably 5.0 at% or less, preferably 3.0 at% or less, more preferably 2.0 at% or less, and even more preferably 1.2 at% or less. More specifically, the atomic percentage of element S is preferably 0.20 at% or more, preferably 0.30 at% or more, and even more preferably 0.50 at% or more. The upper limit is not particularly limited, but is preferably 5.00 at% or less, preferably 3.00 at% or less, more preferably 2.00 at% or less, and even more preferably 1.20 at% or less.

[0029] In the non-aqueous electrolyte battery of this disclosure, the exothermic peak temperature can be improved by forming the aforementioned film on the negative electrode surface. Specifically, the exothermic peak temperature obtained based on a DSC curve measured using a differential thermal scanning calorimeter (DSC) at a heating rate of 10°C / min can be set to 287°C or higher. The upper limit is not particularly limited, but it is 350°C or lower. Furthermore, the exothermic peak temperature can be further improved by repeatedly using the non-aqueous electrolyte battery of this disclosure.

[0030] [Positive electrode] The positive electrode is not particularly limited, but a material that allows reversible insertion and removal of alkali metal ions such as lithium ions and sodium ions, or alkaline earth metal ions, may be used.

[0031] [Positive electrode active material] For example, if the cation is lithium, the positive electrode material (positive electrode active material) is LiCoO ２ LiNiO ２ LiMnO ２ LiMn ２ O ４ Lithium-containing transition metal composite oxides such as those mentioned above, mixtures of multiple transition metals such as Co, Mn, and Ni in those lithium-containing transition metal composite oxides, and those in which some of the transition metals in those lithium-containing transition metal composite oxides are substituted with other metals other than transition metals may also be used.

[0032] Specifically, Li[Ni １／３ Mn １／３ Co １／３ O ２ , Li[Ni ０．４５ Mn ０．３５ Co ０．２ O ２ , Li[Ni ０．５ Mn ０．３ Co ０．２ O ２ , Li[Ni ０．６ Mn ０．２ Co ０．２ O ２ , Li[Ni ０．８ Mn ０．１ Co ０．１ O ２ (hereinafter sometimes referred to as "NCM811"), Li[Ni ０．４９ Mn ０．３ Co ０．２ Zr ０．０１ O ２ , Li[Ni ０．４９ Mn ０．３ Co ０．２ Mg ０．０１ O ２ , LiNi ０．８ Co ０．２ O ２ , LiNi ０．８５ Co ０．１０ Al ０．０５ O ２ , LiNi ０．８７ Co ０．１０ Al ０．０３ O ２ , LiNi ０．９０ Co ０．０７ Al ０．０３ O ２ , LiNi ０．６ Co ０．３ Al ０．１ O ２ , LiNi ０．５ Mn １．５ O ４ , LiNi ０．５ Mn ０．５ O ２ , LiNi ０．１ Mn １．９ O ４ , LiCo ０．５ Mn ０．５ O ２ , 0.5[LiNi０．５ Mn ０．５ O ２ ·0.5[Li ２ MnO ３ , 0.5[LiNi １／３ Co １／３ Mn １／３ O ２ ·0.5[Li ２ MnO ３ , 0.5[LiNi ０．３７５ Co ０．２５ Mn ０．３７５ O ２ ·0.5[Li ２ MnO ３ , 0.5[LiNi ０．３７５ Co ０．１２５ Fe ０．１２５ Mn ０．３７５ O ２ ·0.5[Li ２ MnO ３ , 0.45[LiNi ０．３７５ Co ０．２５ Mn ０．３７５ O ２ ·0.10[Li ２ TiO ３ ·0.45[Li ２ MnO ３ and the like may be mentioned.

[0033] Moreover, a compound represented by Li α M ００１ PO ４ (0<α≦1) which is called olivine may also be used. M ００１ is at least one element selected from the group consisting of Mn, Fe, Co, or Ni. From the viewpoints of battery capacity and cycle characteristics, M ００１ preferably contains Fe, Mn, or both Fe and Mn, and more preferably contains Fe or both Fe and Mn. A part of M ００１ may be substituted with other elements such as Mg, Al, Ti, V, Cr, Zr, and the like. In addition, the olivine-type positive electrode active material may have a simple substance or a compound thereof containing one or more elements selected from the group consisting of B, C, N, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Zn, Zr, and W present on a part or the whole of the particle surface. Specifically, LiFePO ４LiCoPO ４ LiMnPO ４ LiNiPO ４ LiFe ０．５ Mn ０．５ PO ４ LiFe ０．４ Mn ０．６ PO ４ LiFe ０．３ Mn ０．７ PO ４ LiFe ０．５ Mn ０．４ Mg ０．１ PO ４ LiFe ０．５ Mn ０．４５ Zr ０．０５ PO ４ Examples include phosphate compounds of transition metals such as the following.

[0034] Alternatively, layered rock salt type lithium transition metal composite oxides may be used. Examples of layered rock salt type lithium transition metal composite oxides include those represented by the general formula [a]. xLiM ５ O ２ (1-x)Li ２ M ６ O ３ [a] In equation [a], x is a number satisfying 0 < x < 1, and M ５ The average oxidation number is 3. ＋ It is at least one metallic element, M ６ The average oxidation number is 4. ＋ It is at least one metallic element. In formula [a], M ５ This is preferably a single metallic element selected from trivalent Mn, Ni, Co, Fe, V, and Cr, but it may also be a mixture of equal amounts of divalent and tetravalent metals with an average oxidation state of trivalent.

[0035] Also, in formula [a], M ６ It is preferably one or more metallic elements selected from Mn, Zr, and Ti. Specifically, 0.5 [LiNi ０．５ Mn ０．５ O ２ ]・0.5[Li ２ MnO ３ ], 0.5[LiNi １／３ Co １／３ Mn １／３ O２ ]・0.5[Li ２ MnO ３ ], 0.5[LiNi ０．３７５ Co ０．２５ Mn ０．３７５ O ２ ]・0.5[Li ２ MnO ３ ], 0.5[LiNi ０．３７５ Co ０．１２５ Fe ０．１２５ Mn ０．３７５ O ２ ]・0.5[Li ２ MnO ３ ], 0.45[LiNi ０．３７５ Co ０．２５ Mn ０．３７５ O ２ ]・0.10[Li ２ TiO ３ ]・0.45[Li ２ MnO ３ Examples include:

[0036] The positive electrode active material represented by this general formula [a] is known to exhibit high capacity when charged at a high voltage of 4.4 V (Li reference) or higher (for example, U.S. Patent 7,135,252). These positive electrode active materials can be prepared in accordance with the manufacturing methods described in, for example, Japanese Patent Application Publication No. 2008-270201, WO2013 / 118661, Japanese Patent Application Publication No. 2013-030284, etc.

[0037] Also, TiO ２ , V ２ O ５ MoO ３ Oxides such as TiS ２ FeS, MoS ２ Sulfides such as those mentioned above, or conductive polymers such as polyacetylene, poly(p-phenylene), polyaniline, and polypyrrole, activated carbon, radical-generating polymers, carbon materials, etc. may also be used.

[0038] For example, if the cation is sodium, the positive electrode material (positive electrode active material) would be NaCrO ２ NaFe ０．５ Co ０．５ O ２ NaFe ０．４ Mn ０．３ Ni０．３ O ２ NaNi ０．５ Ti ０．３ Mn ０．２ O ２ NaNi １／３ Ti １／３ Mn １／３ O ２ NaNi ０．３３ Ti ０．３３ Mn ０．１６ Mg ０．１７ O ２ Na ２／３ Ni １／３ Ti １／６ Mn １／２ O ２ Na ２／３ Ni １／３ Mn ２／３ O ２ Sodium-containing transition metal composite oxides such as, mixtures of multiple transition metals such as Co, Mn, and Ni in these sodium-containing transition metal composite oxides, and in which some of the transition metals in these sodium-containing transition metal composite oxides are replaced with other metals, NaFePO ４ NaVPO ４ F, Na ３ V ２ (PO ４ ) ３ Na ２ Fe ２ (SO ４ ) ３ Polyanionic compounds such as, composition formula Na β M ００２ γ [Fe(CN)] ６ ] δ The sodium salt of the Prussian blue analog represented by (M ００２ = Represents Cr, Mn, Fe, Co, Ni, Cu, or Zn, with 0 ≤ β ≤ 2, 0.5 ≤ γ ≤ 1.5, 0.5 ≤ δ ≤ 1.5), TiO ２ , V ２ O ５ MoO ３ Oxides such as TiS ２ FeS, MoS ２Sulfides such as those mentioned above, or conductive polymers such as polyacetylene, poly(p-phenylene), polyaniline, and polypyrrole, activated carbon, radical-generating polymers, carbon materials, etc. may also be used.

[0039] [Positive electrode current collector] The positive electrode has a positive electrode current collector. As the positive electrode current collector, for example, aluminum, stainless steel, nickel, titanium, or alloys thereof can be used.

[0040] [Positive Electrode Active Material Layer] The positive electrode is formed by creating a positive electrode active material layer on at least one surface of the positive electrode current collector. The positive electrode active material layer is composed of, for example, the positive electrode active material described above, a binder, and a conductive agent as needed. The binder is similar to that described in [Negative Electrode Active Material Layer].

[0041] As conductive agents, carbon materials such as acetylene black, Ketjen black, furnace black, carbon fibers, graphite (granular graphite or flake graphite), and fluorinated graphite can be used. For the positive electrode, it is preferable to use acetylene black or Ketjen black with low crystallinity.

[0042] [Method for manufacturing electrodes (positive and negative electrodes)] Electrodes can be obtained, for example, by dispersing and kneading an active material, a binder, and optionally a conductive agent in predetermined proportions in a solvent such as N-methyl-2-pyrrolidone (hereinafter sometimes referred to as "NMP") or water, applying the resulting paste to a current collector, and drying it to form an active material layer. It is preferable to compress the obtained electrodes using a method such as a roll press to adjust them to an electrode of appropriate density.

[0043] [Separator] The non-aqueous electrolyte battery of this disclosure may be equipped with a separator. As a separator to prevent contact between the positive electrode and the negative electrode, for example, nonwoven fabrics or porous sheets made of polyolefins such as polypropylene or polyethylene, cellulose, paper, glass fiber, etc. are used. These films are preferably microporous so that the electrolyte can permeate and ions can easily pass through.

[0044] Examples of polyolefin separators include films that electrically insulate the positive and negative electrodes and allow lithium ions to pass through, such as microporous polymer films like porous polyolefin films. Specific examples of porous polyolefin films include, for example, porous polyethylene films alone, or films made by layering porous polyethylene films and porous polypropylene films to form a multilayer film. Other examples include films made by compounding porous polyethylene films and polypropylene films.

[0045] The non-aqueous electrolyte of this disclosure may be impregnated into and retained in the separator described above. There are no particular restrictions on the impregnation method, and any known method may be used. Specifically, impregnation can be achieved by pouring the electrolyte into a battery comprising a positive electrode, a separator, and a negative electrode as the final step.

[0046] [Outer casing] Suitable outer casings for the non-aqueous electrolyte battery of this disclosure include, for example, coin-type, cylindrical, or rectangular metal cans, as well as laminated outer casings. Suitable metal can materials include, for example, nickel-plated steel, stainless steel, nickel-plated stainless steel, aluminum or its alloys, nickel, titanium, etc. Suitable laminated outer casings include, for example, aluminum laminate film, SUS laminate film, silica-coated polypropylene, polyethylene laminate film, etc.

[0047] The configuration of the non-aqueous electrolyte battery according to this embodiment is not particularly limited, but for example, it can be configured such that electrode elements with a positive electrode and a negative electrode facing each other and a non-aqueous electrolyte are enclosed in an outer casing. The shape of the non-aqueous electrolyte battery is not particularly limited, but an electrochemical device in the shape of a coin, cylinder, prismatic, or aluminum laminate sheet can be assembled from the above elements.

[0048] 2. Non-aqueous electrolyte The non-aqueous electrolyte of this disclosure is not particularly limited as long as the effects of the present invention can be obtained, but it comprises (I) an additive compound, (II) a solute (except for (I) the additive compound), and (III) a non-aqueous organic solvent.

[0049] [(I) Additive Compounds] The (I) additive compounds (also referred to as "(I)") contained in the non-aqueous electrolyte of this disclosure will be described below. (I) are additives commonly used in the art of this non-aqueous electrolyte, and are compounds different from solutes commonly used in the art. Examples of (I) in this disclosure include the compounds exemplified below and compounds represented by general formula (1) described later. (I) can be used as one or more selected from these, and it is preferable to include (I-1) a compound represented by general formula (1).

[0050] The compounds that can be used as (I) are, for example, aromatic compounds such as cyclohexylbenzene, cyclohexylfluorobenzene, biphenyl, 2-fluorobiphenyl, tert-butylbenzene, tert-amylbenzene, 2-fluorotoluene, fluorobenzene, and difluoroanisole. Carbonate compounds such as vinylene carbonate (hereinafter sometimes referred to as "VC"), vinylene carbonate oligomers (number average molecular weight in polystyrene terms of 170 to 5000), vinylethylene carbonate, divinylethylene carbonate, fluoroethylene carbonate (hereinafter sometimes referred to as "FEC"), ethynylethylene carbonate, trans-difluoroethylene carbonate, methylpropargyl carbonate, ethylpropargyl carbonate, dipropargyl carbonate, dimethylvinylene carbonate, dimethyl dicarbonate, bis(1,1,1,3,3,3-hexafluoro-1-propyl) carbonate, bis(2,2,2-trifluoroethyl) carbonate, and isocyanate compounds such as 1,6-diisocyanatohexane. Organic acid anhydrides such as maleic anhydride, succinic anhydride, 1,4-dioxan-2,6-dione, glutaric acid anhydride, methanedisulfonic acid anhydride, 1,2-ethanedisulfonic acid anhydride, methanesulfonic acid anhydride, 2-sulfobenzoic acid anhydride, 1,3-propanedisulfonic acid anhydride, 1,3-propanesultone, 1,3-propensultone, 1,4-butanesultone, 2,4-butanesultone, 1,3,2-dioxathiolan-2,2-dioxide, 4-propyl-1,3,2-dioxathiolan-2,2-dioxide, 1,3-dithiolan-1,1,3,3-tetraoxide, 1,3-dithian-1,1,3,3-tetraoxide, 1,2-oxathiolan-5-one-2,2-dioxide, methylenemethanedisulfate, dimethylemethylenemethanedisulfate, trimethylenemethanedisulfate, methyl methanesulfonate, methanesulfonyl fluoride, ethenesulfonyl fluoride, N,Sulfonic acid ester compounds such as N'-carbonylbis(N-methylsulfamoylfluoride) and sulfonyl compounds, boric acid ester compounds such as difluoro(picolinato)borate, phosphate ester compounds such as phenyl difluorophosphate, trippropargyl phosphate, and tetrafluoro(picolinato)phosphate, phosphazene compounds such as (ethoxy)pentafluorocyclotriphosphazene, nitrile compounds such as succinonitrile, silane compounds such as methyldifluorovinylsilane, methylfluorodivinylsilane, dimethyldivinylsilane, trivinylmethylsilane, trivinylfluorosilane, tetravinylsilane, tris(trimethylsilyl)borate, and tris(trimethylsilyl)phosphate, 1,3-dimethyl-1,3-divinyl-1,3-di(1,1,1,3,3,Siloxane compounds such as 3-hexafluoroisopropyl)disiloxane, sulfonates such as fluorosulfonates, trifluoromethanesulfonates, pentafluoroethanesulfonates, and nonafluorobutanesulfonates (preferably fluorosulfonates and trifluoromethanesulfonates), monoalkyl sulfates such as monomethyl sulfate and monoethyl sulfate, Imide salts such as bis(trifluoromethanesulfonyl)imide salt, bis(pentafluoroethanesulfonyl)imide salt, (trifluoromethanesulfonyl)(nonafluorobutanesulfonyl)imide salt, (trifluoromethanesulfonyl)(pentafluoroethanesulfonyl)imide salt, (trifluoromethanesulfonyl)(fluorosulfonyl)imide salt, (pentafluoroethanesulfonyl)(fluorosulfonyl)imide salt, (fluorosulfonyl)(lithium carbonyloxymethanesulfonate)imide salt (preferably bis(trifluoromethanesulfonyl)imide salt, (trifluoromethanesulfonyl)(fluorosulfonyl)imide salt), or imide compounds in which a hydrogen atom is bonded to a nitrogen atom instead of a cation in the above imide salts, phosphates such as monofluorophosphate, difluorophosphate, tetrafluoro(malonato) phosphate, tris(oxalato) phosphate, difluorobis(oxalato) phosphate, tetrafluorooxalato phosphate, Examples include borates such as bis(oxalato)borate, difluorooxalatoborate, and difluoro(malonato)borate; methide salts such as tris(trifluoromethanesulfonyl)methide and tris(fluorosulfonyl)methide; carboxylates such as acrylates and methacrylates; inorganic salts such as nitrates and nitrites; and fluorine-containing alcohols such as hexafluoroisopropanol and trifluoroethanol. The cations in the above salts may be alkali metal ions, alkaline earth metal ions, or quaternary ammonium compounds. Furthermore, the non-aqueous electrolyte of this disclosure may further contain the following compounds as (I) to improve the cycle capacity maintenance rate and gas generation during cycle testing.

[0051]

[0052] The non-aqueous electrolyte of this disclosure further includes, as (I), cyclohexylbenzene, cyclohexylfluorobenzene, biphenyl, 2-fluorobiphenyl, tert-butylbenzene, tert-amylbenzene, 2-fluorotoluene, fluorobenzene, difluoroanisole, vinylene carbonate, oligomers of vinylene carbonate (number average molecular weight in polystyrene terms of 170 to 5000), vinylethylene carbonate, divinylethylene carbonate, fluoroethylene carbonate, ethynylethylene carbonate, trans-difluoroethylene carbonate, methylpropargyl carbonate, ethylpropargyl carbonate, dipropargyl carbonate, dimethylvinylene carbonate, dimethyl dicarbonate, bis(1,1,1,3,3,3-hexafluoro-1-propyl) carbonate, bis(2,2,2-trifluoroethyl) carbonate, 1,6-di Isocyanatohexane, maleic anhydride, succinic anhydride, 1,4-dioxane-2,6-dione, glutaric anhydride, methanedisulfonic anhydride, 1,2-ethanedisulfonic anhydride, methanesulfonic anhydride, 2-sulfobenzoic anhydride, 1,3-propanedisulfonic anhydride, 1,3-propanesultone, 1,3-propensultone, 1,4-butanesultone, 2,4-butanesultone, 1,3,2-dioxathiolan-2,2-dioxide , 4-propyl-1,3,2-dioxathiolan-2,2-dioxide, 1,3-dithiolan-1,1,3,3-tetraoxide, 1,3-dithian-1,1,3,3-tetraoxide, 1,2-oxathiolan-5-one-2,2-dioxide, methylene methane disulfate, dimethyl methane disulfate, trimethylene methane disulfate, methyl methanesulfonate, methanesulfonyl fluoride, ethenesulfonyl fluoride, N,N'-Carbonylbis(N-methylsulfamoylfluoride), difluoro(picolinato)borate, phenyl difluorophosphate, trippropargyl phosphate, tetrafluoro(picolinato)phosphate, (ethoxy)pentafluorocyclotriphosphazene, succinonitrile, methyldifluorovinylsilane, methylfluorodivinylsilane, dimethyldivinylsilane, trivinylmethylsilane, trivinylfluorosilane, tetravinylsilane, tris(trimethyl Silyl) borate, tris(trimethylsilyl) phosphate, 1,3-dimethyl-1,3-divinyl-1,3-di(1,1,1,3,3,3-hexafluoroisopropyl)disiloxane, fluorosulfonate, trifluoromethanesulfonate, pentafluoroethanesulfonate, nonafluorobutanesulfonate, monomethyl sulfate, monoethyl sulfate, bis(trifluoromethanesulfonyl)imide, bis(pentafluoroethanesulfonyl)imide, (trifluoro It is preferable to contain at least one selected from the group consisting of lomethanesulfonyl)(nonafluorobutanesulfonyl)imide salt, (trifluoromethanesulfonyl)(pentafluoroethanesulfonyl)imide salt, (trifluoromethanesulfonyl)(fluorosulfonyl)imide salt, (pentafluoroethanesulfonyl)(fluorosulfonyl)imide salt, (fluorosulfonyl)(lithium carbonyloxymethanesulfonate)imide, monofluorophosphate, difluorophosphate, tetrafluoro(malonato)phosphate, tris(oxalato)phosphate, difluorobis(oxalato)phosphate, tetrafluorooxalatophosphate, bis(oxalato)borate, difluorooxalatoborate, difluoro(malonato)borate, tris(trifluoromethanesulfonyl)methide salt, tris(fluorosulfonyl)methide salt, acrylate, methacrylate, nitrate, nitrite, hexafluoroisopropanol, and trifluoroethanol. By incorporating the above-mentioned compound into the non-aqueous electrolyte of this disclosure, at least one of the following effects may be enhanced: overcharge prevention effect, negative electrode film formation effect, and positive electrode protection effect.

[0053] Furthermore, as is the case when used in non-aqueous electrolyte batteries called lithium polymer batteries, the electrolyte for non-aqueous electrolyte batteries can be pseudo-solidified using a gelling agent or crosslinking polymer. Examples of the polymers mentioned above include polymers having polyethylene oxide as the main chain or side chain, homopolymers or copolymers of polyvinylidene fluoride, methacrylate polymers, and polyacrylonitrile.

[0054] The non-aqueous electrolyte of this disclosure contains (I) in an amount of preferably 0.005% by mass or more, preferably 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and particularly preferably 0.3% by mass or more, based on 100% by mass of the entire non-aqueous electrolyte. The upper limit of (I) is not particularly limited, but preferably it contains in an amount of preferably 70.0% by mass or less, preferably 55.0% by mass or less, preferably 20.0% by mass or less, preferably 10.0% by mass or less, more preferably 8.0% by mass or less, even more preferably 5.0% by mass or less, particularly preferably 3.0% by mass or less, particularly preferably 2.0% by mass or less, and particularly preferably 1.6% by mass or less. This makes it possible to suitably provide a negative electrode with a coating that is superior in thermal stability, can further suppress the initial resistance of the battery, and has superior cycle characteristics.

[0055] Furthermore, the content of fluoroethylene carbonate in (I) may be 0.01% by mass or more and 55.0% by mass or less relative to the total amount of the non-aqueous electrolyte.

[0056] Furthermore, the content of bis(trifluoromethanesulfonyl)imide salts, trifluoromethanesulfonates, and nonafluorobutanesulfonates relative to the total amount of the non-aqueous electrolyte may be 0.01% by mass or more and 20.0% by mass or less.

[0057] Furthermore, the content of bis(1,1,1,3,3,3-hexafluoro-1-propyl) carbonate and bis(2,2,2-trifluoroethyl) carbonate relative to the total amount of the non-aqueous electrolyte may be 0.1% by mass or more and 70.0% by mass or less.

[0058] Furthermore, if (I) is an ionic salt, its cation is more preferably a lithium ion when used in lithium-ion battery applications, and more preferably a sodium ion when used in sodium-ion battery applications.

[0059] The non-aqueous electrolyte of this disclosure may use a total of four or more alkali metal salts by using multiple types of the above-mentioned solutes (such as lithium salts and sodium salts) and salt compounds of (I), depending on the required characteristics. Alternatively, the total of the above-mentioned alkali metal salts may be five or more. The non-aqueous electrolyte of this disclosure is suitably used in the above-mentioned non-aqueous electrolyte battery (preferably a non-aqueous electrolyte secondary battery).

[0060] [(I-1) Compound represented by general formula (1)] In the non-aqueous electrolyte of this disclosure, (I-1) the compound represented by the following general formula (1) (also referred to as "(I-1)") which is preferably included in (I), will be described below.

[0061]

[0062] In general formula (1), M ａ１＋ is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and a1 represents an integer equal to the valency of the corresponding cation.

[0063] M ａ１＋ Preferably, it contains at least one selected from the group consisting of lithium cations, sodium cations, potassium cations, and tetraalkylammonium cations, and more preferably contains lithium cations.

[0064] c1 represents an integer equal to the valence of the corresponding anion. a1 to d1 represent integers from 1 to 2, and a1 × b1 = c1 × d1. X is a sulfur atom or a phosphorus atom, and if X is a sulfur atom, then m is 2, and R ４ It does not exist. If X is a phosphorus atom, then m is 1.

[0065] R １ ~R ４Each of these is an organic group independently selected from a fluorine atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C2-C10 alkenyl group, a C2-C10 alkenyloxy group, a C2-C10 alkynyl group, a C2-C10 alkynyloxy group, a C3-C10 cycloalkyl group, a C3-C10 cycloalkoxy group, a C3-C10 cycloalkenyl group, a C3-C10 cycloalkenyloxy group, a C6-C10 aryl group, and a C6-C10 aryloxy group, and a fluorine atom, an oxygen atom, and an unsaturated bond may also be present in the organic group.

[0066] In this disclosure, "a fluorine atom is present in the organic group" means that at least one of the hydrogen atoms in the organic group is replaced by a fluorine atom. "An oxygen atom is present in the organic group" means that an oxygen atom is present between at least one carbon-carbon bond in the organic group. "An unsaturated bond is present in the organic group" means that at least one carbon-carbon bond in the organic group is an unsaturated bond.

[0067] In the above general formula (1), R １ ~R ４ Examples of alkyl groups having 1 to 10 carbon atoms, represented by , include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, trifluoromethyl group, 2,2-difluoroethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2,2-pentafluoroethyl group, 2,2,3,3-tetrafluoropropyl group, and 1,1,1,3,3,3-hexafluoroisopropyl group. Among these, methyl group, trifluoromethyl group, 2,2,2-trifluoroethyl group, and 1,1,2,2,2-pentafluoroethyl group are preferred.

[0068] Examples of alkoxy groups having 1 to 10 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, pentyloxy, 2,2-difluoroethoxy, 2,2,2-trifluoroethoxy, 2,2,3,3-tetrafluoropropyroxy, and 1,1,1,3,3,3-hexafluoroisopropoxy. Among these, methoxy, 2,2-difluoroethoxy, 2,2,2-trifluoroethoxy, 2,2,3,3-tetrafluoropropyroxy, and 1,1,1,3,3,3-hexafluoroisopropoxy are preferred.

[0069] Examples of alkenyl groups having 2 to 10 carbon atoms include vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, and 1,3-butadienyl groups. Among these, vinyl is preferred. Examples of alkenyloxy groups having 2 to 10 carbon atoms include vinyloxy, allyloxy, 1-propenyloxy, isopropenyloxy, 2-butenyloxy, and 1,3-butadienyloxy groups. Among these, allyloxy is preferred.

[0070] Examples of alkynyl groups having 2 to 10 carbon atoms include ethynyl group, 2-propynyl group, and 1,1-dimethyl-2-propynyl group. Examples of alkynyloxy groups having 2 to 10 carbon atoms include ethynyloxy group, 2-propynyloxy group, and 1,1-dimethyl-2-propynyloxy group. Among these, the 2-propynyloxy group is preferred.

[0071] Examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopentyl groups and cyclohexyl groups. Examples of cycloalkoxy groups having 3 to 10 carbon atoms include cyclopentyloxy groups and cyclohexyloxy groups.

[0072] Examples of cycloalkenyl groups having 3 to 10 carbon atoms include cyclopentenyl groups and cyclohexenyl groups. Examples of cycloalkenyloxy groups having 3 to 10 carbon atoms include cyclopentenyloxy groups and cyclohexenyloxy groups.

[0073] Examples of aryl groups having 6 to 10 carbon atoms include phenyl, 2-fluorophenyl, pentafluorophenyl, tolyl, and xylyl groups. Among these, phenyl, 2-fluorophenyl, and pentafluorophenyl groups are preferred. Examples of aryloxy groups having 6 to 10 carbon atoms include phenyloxy, 2-fluorophenyloxy, pentafluorophenyloxy, tolyl, and xylyloxy groups. Among these, phenyloxy is preferred.

[0074] When the coating on the negative electrode surface of the present disclosure contains S element, the origin of the S element is not particularly limited, but it is preferable that it originates from (I-1), in which X in general formula (1) is a sulfur atom.

[0075] (I-1) preferably has at least one P-F bond or S-F bond. Having these bonds provides excellent low-temperature properties.

[0076] The non-aqueous electrolyte of this disclosure contains (I-1) in an amount of preferably 0.005% by mass or more, preferably 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and particularly preferably 0.3% by mass or more, based on 100% by mass of the entire non-aqueous electrolyte. The upper limit of (I-1) is not particularly limited, but it is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, even more preferably 5.0% by mass or less, particularly preferably 3.0% by mass or less, particularly preferably 2.0% by mass or less, and particularly preferably 1.6% by mass or less. This makes it possible to suitably provide a negative electrode with a coating that is superior in thermal stability, can further suppress the initial resistance of the battery, and has superior cycle characteristics.

[0077] [(II) Solute] The (II) solute (also referred to as "(II)") contained in the non-aqueous electrolyte of this disclosure will be described below. The (II) solute does not contain (I) additive compounds or (I-1) compounds represented by general formula (1).

[0078] (II) The solute can be any type of solute that has been conventionally used in the field of non-aqueous electrolytes, without any particular limitations. Such a solute is preferably an ionic salt consisting of any pair of cation and anion, and any type of solute can be used without any particular limitations, as long as it exists in an ionic state as a cation and anion in a non-aqueous organic solvent.

[0079] Preferably, such a solute is an ionic salt consisting of a pair of at least one cation selected from the group consisting of alkali metal ions such as lithium ions and sodium ions, alkaline earth metal ions, and quaternary ammonium, and at least one anion selected from the group consisting of hexafluorophosphate anion, tetrafluoroborate anion, hexafluoroantimonate anion, hexafluoroarsenate anion, perchlorate anion, bis(fluorosulfonyl)imide anion, aluminate anion, tetrachloroaluminate anion, chloride ion, and iodide ion.

[0080] Specifically, LiPF ６ LiBF ４ LiSbF ６ LiAsF ６ LiClO ４ , LiN (SO ２ F) ２ LiAlO ２ LiAlCl ４ , at least one selected from the group consisting of LiCl and LiI, or NaPF ６ NaBF ４ NaSbF ６ NaAsF ６ NaClO ４ NaN(SO ２ F) ２ NaAlO ２ NaAlCl ４ At least one selected from the group consisting of NaCl and NaI can be preferably listed.

[0081] In particular, considering the energy density, output characteristics, and lifespan of the non-aqueous electrolyte battery, it is preferable that the cation be at least one selected from the group consisting of lithium ions, sodium ions, potassium ions, magnesium ions, and quaternary ammonium cations, and that the anion be at least one selected from the group consisting of hexafluorophosphate anions, tetrafluoroborate anions, and bis(fluorosulfonyl)imide anions.

[0082] The non-aqueous electrolyte of this disclosure may be (II) used as a single compound, or it may be used as a mixture of two or more compounds in any combination and ratio depending on the application.

[0083] There are no particular restrictions on the concentration of (II) relative to the total amount of non-aqueous electrolyte. For example, the lower limit of the concentration of (II) may be 0.5 mol / L or higher, 0.7 mol / L or higher, or 0.9 mol / L or higher. The upper limit of the concentration of (II) may be 5 mol / L or lower, 4 mol / L or lower, or 2 mol / L or lower. A concentration of 0.5 mol / L or higher is preferable because it does not easily reduce ionic conductivity, and the cycle characteristics and output characteristics of the non-aqueous electrolyte battery do not easily deteriorate. On the other hand, a concentration of 5 mol / L or lower is preferable because it does not easily increase the viscosity of the non-aqueous electrolyte and does not easily reduce ionic conductivity. When two or more types of (II) are used, it is preferable that the total concentration of those solutes is within the above range.

[0084] The temperature at which (II) is dissolved in (III) a non-aqueous organic solvent is not particularly limited, but may be -20 to 80°C or 0 to 60°C.

[0085] Furthermore, the cations of the solute are more preferably lithium ions when used in lithium-ion battery applications, and more preferably sodium ions when used in sodium-ion battery applications.

[0086] [(III) Non-aqueous Organic Solvents] The (III) non-aqueous organic solvent (also referred to as "(III)") contained in the non-aqueous electrolyte of this disclosure will be described below. The type of (III) non-aqueous organic solvent is not particularly limited, and any non-aqueous organic solvent can be used. Such non-aqueous organic solvents preferably contain at least one selected from the group consisting of cyclic esters, linear esters, cyclic ethers, linear ethers, sulfone compounds, sulfoxide compounds, amide compounds, nitrile compounds, and ionic liquids, and more preferably contain at least one selected from the group consisting of cyclic esters, linear esters, cyclic ethers, linear ethers, sulfone compounds, sulfoxide compounds, and ionic liquids. Note that cyclic carbonates are a sub-concept of cyclic esters, and linear carbonates are a sub-concept of linear esters. Specific examples of (III) non-aqueous organic solvents include the following non-aqueous organic solvents.

[0087] Examples of cyclic esters include cyclic carbonates such as propylene carbonate (hereinafter sometimes referred to as "PC"), ethylene carbonate (hereinafter sometimes referred to as "EC"), and butylene carbonate, as well as γ-butyrolactone and γ-valerolactone.

[0088] Examples of chain esters include diethyl carbonate (hereinafter sometimes referred to as "DEC"), dimethyl carbonate (hereinafter sometimes referred to as "DMC"), ethyl methyl carbonate (hereinafter sometimes referred to as "EMC"), methyl propyl carbonate, ethyl propyl carbonate, methyl butyl carbonate, 2,2,2-trifluoroethyl methyl carbonate, 2,2,2-trifluoroethyl ethyl carbonate, and 2,2,2-trifluoroethyl propyl carbonate. Examples include linear carbonates such as carbonates, 1,1,1,3,3,3-hexafluoro-1-propylmethyl carbonate, 1,1,1,3,3,3-hexafluoro-1-propylethyl carbonate, and 1,1,1,3,3,3-hexafluoro-1-propylpropyl carbonate, as well as methyl acetate, ethyl acetate, methyl propionate, ethyl propionate (hereinafter sometimes referred to as "EP"), methyl 2-fluoropropionate, and ethyl 2-fluoropropionate.

[0089] Examples of cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, furan, tetrahydropyran, 1,3-dioxane, 1,4-dioxane, 1,3-dioxolane, and trioxane.

[0090] Examples of linear ethers include diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, dimethoxymethane, trimethoxymethane, 1,2-dimethoxyethane, diethoxyethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

[0091] Other examples include sulfone compounds such as dimethyl sulfoxide and sulfolane, sulfoxide compounds, N,N-dimethylformamide, acetonitrile, and propionitrile. Ionic liquids can also be mentioned.

[0092] The cyclic ester may contain a cyclic carbonate, and the cyclic carbonate may contain at least one selected from the group consisting of ethylene carbonate and propylene carbonate.

[0093] The linear ester may contain a linear carbonate, and the linear carbonate may contain at least one selected from the group consisting of ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, and methyl propyl carbonate.

[0094] The cyclic ether may include at least one selected from the group consisting of tetrahydrofuran, 2-methyltetrahydrofuran, furan, tetrahydropyran, 1,3-dioxane, 1,4-dioxane, 1,3-dioxolane, and trioxane.

[0095] The chain-like ether may include at least one selected from the group consisting of diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, dimethoxymethane, trimethoxymethane, 1,2-dimethoxyethane, diethoxyethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

[0096] The non-aqueous electrolyte of this disclosure may be (III) in which a single compound is used alone, or two or more compounds may be mixed in any combination and ratio according to the application. Among these, it is particularly preferable to include at least one selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC), from the viewpoint of electrochemical stability with respect to oxidation and reduction and chemical stability with respect to heat and reaction with the solute.

[0097] Furthermore, it is preferable to include, for example, one or more cyclic carbonates with high dielectric constants and one or more chain carbonates or chain esters with low liquid viscosity as the non-aqueous organic solvent, because this increases the ionic conductivity of the electrolyte. Specifically, the following combinations are more preferable. (1) Combination of EC and EMC, (2) Combination of EC and DEC, (3) Combination of EC, DMC and EMC, (4) Combination of EC, DEC and EMC, (5) Combination of EC, EMC and EP, (6) Combination of PC and DEC, (7) Combination of PC and EMC, (8) Combination of PC and EP, (9) Combination of PC, DMC and EMC, (10) Combination of PC, DEC and EMC, (11) Combination of PC, DEC and EP, (12) Combination of PC, EC and EMC, (13) Combination of PC, EC, DMC and EMC, (14) Combination of PC, EC, DEC and EMC, (15) Combination of PC, EC, EMC and EP

[0098] The concentration of the non-aqueous organic solvent in this disclosure is not particularly limited as long as it functions as a non-aqueous organic solvent, but it may be, for example, 40 to 99% by mass, preferably 50 to 95% by mass, and particularly preferably 70 to 93% by mass, based on the total amount (100% by mass) of the non-aqueous electrolyte.

[0099] The content of the cyclic carbonate is not particularly limited and is arbitrary as long as it does not significantly impair the effects of this disclosure. However, when using one type alone, the content may be 3% by volume or more, and more preferably 5% by volume or more, in 100% by volume of the non-aqueous organic solvent. By setting it within this range, a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte is avoided, and it becomes easier to achieve good high-current discharge characteristics, stability to the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery. Alternatively, it may be 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. By setting it within this range, the viscosity of the non-aqueous electrolyte is set within an appropriate range, a decrease in ionic conductivity is suppressed, and consequently it becomes easier to achieve good load characteristics of the non-aqueous electrolyte battery.

[0100] Furthermore, cyclic carbonates can be used in any combination of two or more types. One preferred combination is ethylene carbonate and propylene carbonate. In this case, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99:1 to 40:60, and particularly preferably 95:5 to 50:50. Moreover, the amount of propylene carbonate in the total non-aqueous organic solvent is not particularly limited and is arbitrary as long as it does not significantly impair the effects of this disclosure, but it may be 1% by volume or more, preferably 2% by volume or more, more preferably 3% by volume or more, also 30% by volume or less, preferably 25% by volume or less, and more preferably 20% by volume or less. Including propylene carbonate within this range is preferable because, for example, when combining ethylene carbonate with dialkyl carbonates, the low-temperature characteristics are further improved while maintaining the characteristics of the combination of ethylene carbonate and dialkyl carbonates. The chain-like esters may be used individually, or two or more may be used in any combination and ratio.

[0101] The content of the linear ester is not particularly limited, but it may be 15% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more, or 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less, based on 100% by volume of the non-aqueous organic solvent. By setting the content of the linear ester within the above range, the viscosity of the non-aqueous electrolyte can be set to an appropriate range, the decrease in ionic conductivity can be suppressed, and consequently, the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte battery can be set to a good range. In addition, the decrease in electrical conductivity due to the decrease in dielectric constant of the non-aqueous electrolyte can be avoided, and the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte battery can be set to a good range. Furthermore, by combining a specific linear ester with ethylene carbonate in a specific content, the battery performance can be significantly improved.

[0102] For example, when dimethyl carbonate, ethyl methyl carbonate, or a mixture of dimethyl carbonate and ethyl methyl carbonate is selected as a specific chain ester, the content of ethylene carbonate is not particularly limited and is arbitrary as long as it does not significantly impair the effects of this disclosure, but it may be 5% by volume or more, preferably 10% by volume or more, also 45% by volume or less, and preferably 40% by volume or less. The content of dimethyl carbonate may be 20% by volume or more, preferably 30% by volume or more, also 50% by volume or less, and preferably 45% by volume or less. The content of ethyl methyl carbonate may be 20% by volume or more, preferably 30% by volume or more, also 50% by volume or less, and preferably 45% by volume or less. By setting the content within the above ranges, the low-temperature deposition temperature of the electrolyte is reduced, the viscosity of the non-aqueous electrolyte is also reduced, the ionic conductivity is improved, and it becomes easier to obtain high input and output even at low temperatures.

[0103] The content of the chain ether is not particularly limited and is arbitrary as long as it does not significantly impair the effects of this disclosure. However, it may be 1% by volume or more, preferably 2% by volume or more, more preferably 3% by volume or more, or 30% by volume or less, preferably 25% by volume or less, and more preferably 20% by volume or less, per 100% by volume of non-aqueous organic solvent. If the content of the chain ether is within the above range, for example, in the case of a lithium-ion battery in which the cation is mainly lithium, it is easy to ensure the effect of improving ionic conductivity due to the improved degree of lithium ion dissociation of the chain ether and the decrease in viscosity. Furthermore, when the negative electrode active material is a carbonaceous material, the phenomenon of co-insertion of the chain ether together with lithium ions can be suppressed, making it easier to set the input / output characteristics and charge / discharge rate characteristics within an appropriate range.

[0104] The content of the sulfone compound is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present disclosure. However, it may be 0.3% by volume or more, preferably 0.5% by volume or more, more preferably 1% by volume or more, or 40% by volume or less, preferably 35% by volume or less, and more preferably 30% by volume or less, based on 100% by volume of the non-aqueous organic solvent. If the content of the sulfone compound is within the above range, it is easier to obtain effects that improve durability such as cycle characteristics and storage characteristics, and it is also possible to set the viscosity of the non-aqueous electrolyte within an appropriate range, avoid a decrease in electrical conductivity, and make it easier to set the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte battery within an appropriate range.

[0105] 3. Method for Manufacturing a Non-Aqueous Electrolyte Battery The method for manufacturing a non-aqueous electrolyte battery according to this disclosure comprises the steps of injecting the non-aqueous electrolyte described above and forming a film on the surface of the negative electrode. There are no particular restrictions on the method of injection, and conventional methods can be used. For example, vacuum injection is one such method.

[0106] As described above, a non-aqueous electrolyte battery is prepared, and then a step of forming a film on the negative electrode surface is performed. Specifically, the first charging step is to charge the battery to a first charge state where the C rate is 0.05C to 0.3C, preferably 0.08C to 0.27C, more preferably 0.1C to 0.25C, and the charge state is 5% to 30%, preferably 7% to 25%, more preferably 9% to 15%, when the fully charged state is 100%, and then hold the battery at an ambient temperature of 25°C to 50°C for 4 to 72 hours, preferably 12 to 68 hours, more preferably 24 to 64 hours. Specifically, the second charging step involves charging to a second charge state where the C rate is 0.1C to 0.5C, preferably 0.13C to 0.4C, more preferably 0.15C to 0.3C, and the charge state is 40% to 60%, preferably 42% to 56%, more preferably 45% to 52% when the fully charged state is 100%, and then holding the battery at an ambient temperature of 45°C to 65°C for 4 to 350 hours, preferably 24 to 200 hours, more preferably 48 to 150 hours. Through this step, a non-aqueous electrolyte battery equipped with the coated negative electrode of the present disclosure can be obtained.

[0107] Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted as long as they do not impair the effects of the present invention.

[0108] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0109] [Preparation of Non-Aqueous Electrolyte] (Preparation of Comparative Non-Aqueous Electrolyte 1-1) EC, DMC, and EMC were mixed in a volume ratio of EC:DMC:EMC = 3:4:3 in an argon atmosphere with a dew point of -50°C or lower. Then, while maintaining the internal temperature below 40°C, LiPF was added to a concentration of 1.15 mol / L relative to the total volume of the non-aqueous electrolyte. ６ Comparative non-aqueous electrolyte 1-1 of Comparative Example 1-1 was prepared by adding the following. The abbreviations above are as follows: EC: ethylene carbonate DMC: dimethyl carbonate EMC: ethyl methyl carbonate

[0110] (Preparation of non-aqueous electrolytes 1-1 to 1-8 and comparative non-aqueous electrolyte 1-2) EC, DMC, and EMC were mixed in a volume ratio of EC:DMC:EMC = 3:4:3 in an argon atmosphere with a dew point of -50°C or lower. Then, while maintaining the internal temperature below 40°C, LiPF was prepared to a concentration of 1.15 mol / L relative to the total volume of the non-aqueous electrolyte. ６ By adding the compound represented by the following chemical formula (1-1) (1-1) or the compound represented by the following chemical formula (1-2) (1-2), which corresponds to the compound represented by general formula (1), to the total amount of non-aqueous electrolyte solution, the concentration shown in Table 1 was added, and the mixture was stirred for 1 hour to dissolve it, thereby preparing non-aqueous electrolyte solutions 1-1 to 1-8 of Examples 1-1 to 1-8 in Table 1, and comparative non-aqueous electrolyte solution 1-2 of Comparative Example 1-2.

[0111]

[0112]

[0113] [Fabrication of Non-Aqueous Electrolyte Batteries] (Fabrication of NCM811 Positive Electrode) LiNi ０．８ Mn ０．１ Co ０．１ O ２A cathode composite paste was prepared by mixing 92.0% by mass of powder with 3.5% by mass of polyvinylidene fluoride (PVDF) as a binder and 4.5% by mass of acetylene black as a conductive material, and then adding N-methyl-2-pyrrolidone (NMP). This paste was applied to both sides of aluminum foil (A1085), dried, and pressurized, and then punched out to a 4cm x 5cm rectangle to obtain a test NCM811 cathode.

[0114] (Preparation of Natural Graphite Anode) A negative electrode mixture paste was prepared by mixing 92.0% by mass of natural graphite powder, 3.0% by mass of conductive material (Denka, HS-100), 2.0% by mass of carbon nanofiber (Showa Denko, VGCF), 2.0% by mass of styrene-butadiene rubber (hereinafter also referred to as "SBR"), 1.0% by mass of carboxymethylcellulose sodium (hereinafter also referred to as "CMC"), and water. This paste was applied to one side of a copper foil, dried, and then punched out to 4.5 cm x 5.5 cm to obtain a test natural graphite anode.

[0115] (Fabrication of Non-Aqueous Electrolyte Batteries) In an argon atmosphere with a dew point of -50°C or lower, terminals were welded to the NCM811 positive electrode as described above. Then, the positive electrode was sandwiched between two polyethylene separators (5 cm x 6 cm) on both sides, and further sandwiched on the outside by two natural graphite negative electrodes with terminals welded to them beforehand, so that the negative electrode active material surface faced the positive electrode active material surface. These were then placed in an aluminum laminate bag with an opening on one side, and after vacuum injection of the non-aqueous electrolyte described in Table 1, the opening was sealed with heat to produce aluminum laminate type non-aqueous electrolyte batteries according to the examples and comparative examples in Tables 1 and 2. Note that n=2 non-aqueous electrolyte batteries were produced for each of Tables 1 and 2, and the subsequent evaluations were also carried out for each of these n=2 samples. Note that the evaluation results described in Tables 1 and 2 below are the average values ​​for n=2.

[0116] [Initial Coating Formation] (Examples 1-1 to 1-8, Comparative Example 1-1) First, the initial coating formation process was carried out using the fabricated cells under the following conditions. Specifically, as the first charging step, constant current charging was performed at a maximum charging voltage of 3.5V and 9mA (first SOC was 10%), and the voltage was maintained for 60 hours at an ambient temperature of 45°C. After that, the temperature was lowered to 25°C, and as the second charging step, constant current charging was performed at a maximum charging voltage of 3.8V and 9mA (second SOC was 50%), and the voltage was maintained for 120 hours at an ambient temperature of 60°C. Here, as a method for calculating SOC, the charging capacity when a separate cell is charged with a constant current at a maximum charging voltage of 4.2V and 9mA was determined in advance. Using this charging capacity as a reference (this state is defined as SOC = 100%), the relative ratio (percentage) of the charging capacity in the first charging process was calculated as the first SOC, and the relative ratio (percentage) of the charging capacity in the second charging process was calculated as the second SOC. The conditions for the first and second charging processes are shown in Table 1.

[0117] (Comparative Example 1-2) The initial coating formation process was carried out under the following conditions. Specifically, the charging process consisted of one stage, in which constant current charging was performed at an ambient temperature of 25°C with a maximum charging voltage of 4.2V and 45mA (SOC was 100%), and the voltage was maintained for 180 hours at an ambient temperature of 45°C.

[0118] <Analysis of the negative electrode coating (XPS measurement)> The non-aqueous electrolyte battery, after the initial coating formation process described above was completed, was opened in an argon-atmosphere glove box. A small amount of the coated negative electrode was cut out from the battery, washed with ethyl methyl carbonate, and then dried. The coating on the negative electrode was selectively removed by Ar etching, and X-ray photoelectron spectroscopy was performed. When the XPS reached the negative electrode surface, SiO ２ The etching depth, calculated using a converted value, was measured at a position 10 nm back in the film thickness direction (etching direction). Specifically, X-ray photoelectron spectroscopy measurements were performed using an X-ray photoelectron spectroscopy (XPS) analyzer (ULVAC-PHI VersaProbe 5000II). From the resulting photoelectron spectroscopy spectra, the peak areas of each element shown below were obtained. For the total peak area of ​​these peak areas C, O, F, P, N, and S, the atomic percentage A of element P was calculated from the peak area P. ｐ(at%), atomic percentage A of element N calculated from peak area N. Ｎ (at%), atomic percentage A of element S calculated from peak area S. Ｓ (at%) was calculated. Next, the sum of the atomic percentages of elements P, N, and S (A) was calculated. Ｐ +A Ｎ +A Ｓ ), the sum of the atomic percentages of elements P and N (A Ｐ +A Ｎ ) calculate the ratio "(A Ｐ +A Ｎ ) / ( A Ｐ +A Ｎ +A Ｓ The following values ​​were calculated: C1s: 6.992 N1s: 46.713 O1s: 34.094 F1s: 46.641 P2p: 56.505 S2p: 76.458

[0119] <Differential Scanning Calorimetry (DSC Measurement) of the Negative Electrode> The non-aqueous electrolyte battery, after the initial coating formation process described above was completed, was charged to 100% by constant current and constant voltage charging at 25°C with a maximum charging voltage of 4.2V and 9mA. Subsequently, the laminated battery was opened in an argon-atmosphere glove box. A small amount of the coated negative electrode (with electrolyte attached) was cut out from the battery and sealed in a SUS differential scanning calorimetry (DSC) sealed container. DSC measurement was performed using a Hitachi High-Tech XSTC-7000 with nitrogen gas flowing through the measurement system, and the exothermic behavior was measured when the temperature was raised to a maximum temperature of 400°C at a rate of 10°C / min. Table 2 shows the obtained "Exothermic Peak Temperature / °C (Initial): Apex Temperature A" and the increase compared to the "Exothermic Peak Temperature (Initial): Apex Temperature B" of Comparative Example 1-1 as "Apex Temperature A - Apex Temperature B / °C".

[0120] <Measurement of DC Resistance of Battery After Initial Film Formation> The non-aqueous electrolyte battery, after the initial film formation process described above was completed, was charged to 50% by constant current charging at 9mA with a maximum charging voltage of 3.8V at 25°C. Subsequently, the DC resistance was calculated from the correlation between current and voltage when charging at 9mA, 22.5mA, 45mA, and 90mA for 10 seconds, and is listed in Table 2 as "Initial Resistance / Ω". In addition, the relative value of the initial resistance of each example and comparative example, with the initial resistance of Comparative Example 1-1 set to 100%, is listed as "Relative Initial Resistance / %".

[0121] <Differential Scanning Calorimetry (DSC Measurement) and DC Resistance Measurement of the Negative Electrode After Cycle Testing> The battery was placed in a 45°C constant temperature bath and connected to a charge / discharge device. Constant current and constant voltage charging was performed at a maximum charging voltage of 4.2V and 45mA. Next, constant current discharge was performed at a minimum discharge voltage of 2.5V and 45mA. This constituted one charge / discharge cycle, and a total of 150 charge / discharge cycles were performed. After the cycle test, differential scanning calorimetry (DSC measurement) of the negative electrode was performed in the same manner as above. Table 2 shows the obtained peak heat generation temperature (after cycle) and the increase compared to the peak heat generation temperature (after cycle) of Comparative Example 1-1. In addition, DC resistance measurement was performed in the same manner as above after the cycle test, and the post-cycle resistance of Comparative Example 1-1 was set to 100% for comparison. The results are shown in Table 2. In Comparative Example 1-2, delamination was observed at the interface after the cycle test, confirming a decrease in mechanical strength.

[0122] <Capacity Retention Rate After Cycle Testing> A battery with a predetermined initial coating was placed in a 25°C constant temperature bath and connected to a charge / discharge device. Constant current and constant voltage charging was performed at a maximum charge voltage of 4.2V and 9mA. Next, constant current discharge was performed at a minimum discharge voltage of 2.5V and 9mA, and this discharge capacity was taken as the initial capacity. After the above cycle test, the non-aqueous electrolyte battery was charged at an ambient temperature of 25°C with a maximum charge voltage of 4.2V and 9mA. Next, constant current discharge was performed at a minimum discharge voltage of 2.5V and 9mA, and the discharge capacity at that time was measured. The capacity retention rate after the cycle relative to the initial capacity was calculated and recorded in Table 2 as "Cycle Retention Rate / %". In addition, Table 2 also shows the "Relative Cycle Retention Rate / %" as the relative value of the capacity retention rate of each example, with the capacity retention rate after the cycle of Comparative Example 1-1 set to 100.

[0123]

[0124]

[0125] From the results in Table 2, the sum of the atomic percentages of elements P, N, and S (A ｐ +A Ｎ +A Ｓ ) is within the range of greater than 1.0 at% and less than or equal to 7.0 at%, and the sum of the atomic percentages of P and N elements (A Ｐ +A Ｎ In the example using a coated negative electrode with a heat content of 0.4 at% or more, the main peak temperature of heat generation shifted to a higher temperature compared to the comparative example, confirming excellent thermal stability of the negative electrode in a fully charged state. Furthermore, A Ｓ Examples using a coated negative electrode with a concentration of 0.2 at% or more, particularly Examples 1-1 and 1-2, are more A than the other examples. ｐ +A Ｎ Even if the amount is small, A Ｓ The inclusion of 0.2 at% or more of this compound improved thermal stability. Furthermore, the non-aqueous electrolyte battery of the example had a low initial resistance, and the decrease in capacity and increase in resistance were suppressed after the cycle test.

[0126] The exothermic reaction is thought to occur due to the thermal decomposition of the electrolyte itself and the thermal release of lithium inserted between the graphite layers. Although the details are unclear, it is believed that by performing an initial film formation process under predetermined conditions, component (I-1) forms a film of a specific configuration on the negative electrode surface, thereby suppressing these complex exothermic reactions. Furthermore, in the embodiment where a film in a specific state as defined in this invention is provided on the negative electrode, it was confirmed that the initial resistance of the battery could be suppressed. On the other hand, in Comparative Example 1-2, the initial film formation process involved one charge-discharge cycle between 4.2 and 2.5V at 45mA and 25°C, but no heating or potential holding was performed, and it is thought that the film amount was insufficient, resulting in no effect being obtained. Moreover, in the non-aqueous electrolyte battery of the embodiment, the decrease in capacity and increase in resistance were suppressed after the cycle test.

[0127] This application claims priority based on Japanese Patent Application No. 2025-068794, filed on 18 April 2025, and incorporates all of its disclosures herein.

Claims

1. A non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte, wherein a film is formed on the surface of the negative electrode, and SiO is present in the film thickness direction from the surface of the negative electrode. ２ A non-aqueous electrolyte battery in which, in an X-ray photoelectron spectroscopy measurement at a position of 10 nm (converted value), the sum of the atomic percentages a of P, N, and S elements, based on the total atomic amounts of C, O, F, P, N, and S elements contained in the coating on the negative electrode surface, is in the range of greater than 1.0 at% and less than or equal to 7.0 at%, and the sum of the atomic percentages b of P and N elements is 0.4 at% or more.

2. A non-aqueous electrolyte battery according to claim 1, wherein the ratio of the total value b to the total value a (b / a) is 0.5 or more and 1.0 or less.

3. A non-aqueous electrolyte battery according to claim 1 or 2, wherein the non-aqueous electrolyte comprises (I-1) a compound represented by the following general formula (1). [In general formula (1), M ａ１＋ X is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and a1 represents an integer equal to the valency of the corresponding cation. a1 to d1 represent integers from 1 to 2, and a1 × b1 = c1 × d1. X is a sulfur atom or a phosphorus atom, and if X is a sulfur atom, then m is 2, and R ４ It does not exist, and when X is a phosphorus atom, m is 1. １ ~R ４ Each of these is an organic group independently selected from a fluorine atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C2-C10 alkenyl group, a C2-C10 alkenyloxy group, a C2-C10 alkynyl group, a C2-C10 alkynyloxy group, a C3-C10 cycloalkyl group, a C3-C10 cycloalkoxy group, a C3-C10 cycloalkenyl group, a C3-C10 cycloalkenyloxy group, a C6-C10 aryl group, and a C6-C10 aryloxy group, and a fluorine atom, oxygen atom, or unsaturated bond may also be present in the organic group.

4. A non-aqueous electrolyte battery according to claim 3, wherein the X of the compound represented by general formula (1) is a sulfur atom.

5. A non-aqueous electrolyte battery according to claim 4, wherein the coating contains element S.

6. A non-aqueous electrolyte battery according to claim 5, wherein SiO is present in the film thickness direction from the negative electrode surface of the coating. ２ A non-aqueous electrolyte battery in which, in an X-ray photoelectron spectroscopy measurement at a position of 10 nm (converted value), the atomic percentage of element S is 0.2 at% or more, based on the total atomic amounts of elements C, O, F, P, N, and S contained in the coating on the negative electrode surface.

7. A non-aqueous electrolyte battery according to any one of claims 1 to 6, wherein the negative electrode contains graphite.

8. A non-aqueous electrolyte battery according to any one of claims 1 to 7, wherein the positive electrode contains a layered rock salt type lithium transition metal composite oxide.

9. A non-aqueous electrolyte battery according to any one of claims 3 to 6, wherein the compound represented by general formula (1) has at least one P-F bond or S-F bond.

10. A non-aqueous electrolyte battery according to any one of claims 3 to 6, wherein (I-1) M of a compound represented by general formula (1) ａ１＋ A non-aqueous electrolyte battery comprising at least one selected from the group consisting of lithium cations, sodium cations, potassium cations, and tetraalkylammonium cations.

11. A negative electrode having a coating on its surface, wherein the coating has SiO2 in the direction of film thickness from the negative electrode surface. ２ A negative electrode in which, in an X-ray photoelectron spectroscopy measurement at a position of 10 nm (converted value), the sum of the atomic percentages a of P, N, and S elements, based on the total atomic amounts of C, O, F, P, N, and S elements contained in the coating on the negative electrode surface, is in the range of greater than 1.0 at% and less than or equal to 7.0 at%, and the sum of the atomic percentages b of P and N elements is 0.4 at% or more.

12. A negative electrode according to claim 11, wherein the ratio of the total value b to the total value a (b / a) is 0.5 or more and 1.0 or less.

13. A negative electrode according to claim 11 or 12, wherein the coating contains an element S.

14. The negative electrode according to claim 13, wherein in a direction of film thickness from the surface of the negative electrode of the coating film, SiO ２ In an X-ray photoelectron spectroscopy measurement at a position of 10 nm in terms of converted value, the atomic percentage of S element is 0.2 at% or more based on the total atomic amount of C, O, F, P, N, and S elements contained in the coating film on the surface of the negative electrode. Negative electrode.

15. A negative electrode according to any one of claims 11 to 14, wherein the negative electrode contains graphite.

16. A method for manufacturing a non-aqueous electrolyte battery, comprising the steps of: preparing a non-aqueous electrolyte battery comprising: a positive electrode; a negative electrode; a non-aqueous electrolyte; and (I) a non-aqueous electrolyte containing an additive compound; and forming a film on the surface of the negative electrode of the non-aqueous electrolyte battery, wherein the step of forming the film comprises: a first charging step of charging to a first charging state in which the C rate is 0.05C to 0.3C and the charge state is 5% to 30% when the fully charged state is 100%, and then holding the ambient temperature at 25°C to 50°C for 4 to 72 hours; and a second charging step of charging to a second charging state in which the C rate is 0.1C to 0.5C and the charge state is 40% to 60% when the fully charged state is 100%, and then holding the ambient temperature at 45°C to 65°C for 4 to 350 hours.

17. A method for producing a non-aqueous electrolyte battery according to claim 16, wherein (I) the additive compound comprises (I-1) a compound represented by the following general formula (1). [In general formula (1), M ａ１＋ X is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and a1 represents an integer equal to the valency of the corresponding cation. a1 to d1 represent integers from 1 to 2, and a1 × b1 = c1 × d1. X is a sulfur atom or a phosphorus atom, and if X is a sulfur atom, then m is 2, and R ４ It does not exist, and when X is a phosphorus atom, m is 1. １ ~R ４ Each of these is an organic group independently selected from a fluorine atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C2-C10 alkenyl group, a C2-C10 alkenyloxy group, a C2-C10 alkynyl group, a C2-C10 alkynyloxy group, a C3-C10 cycloalkyl group, a C3-C10 cycloalkoxy group, a C3-C10 cycloalkenyl group, a C3-C10 cycloalkenyloxy group, a C6-C10 aryl group, and a C6-C10 aryloxy group, and a fluorine atom, oxygen atom, or unsaturated bond may also be present in the organic group.

18. A method for manufacturing a non-aqueous electrolyte battery according to claim 17, wherein (I-1) the X of the compound represented by general formula (1) is a sulfur atom.

19. The device comprises a positive electrode, a negative electrode, and a non-aqueous electrolyte, wherein a coating is formed on the surface of the negative electrode, and SiO is present in the film thickness direction from the surface of the negative electrode. ２ In an X-ray photoelectron spectroscopy measurement at a position of 10 nm (converted value), the sum of the atomic percentages a of P, N, and S elements, based on the total atomic amounts of C, O, F, P, N, and S elements contained in the film on the negative electrode surface, is in the range of greater than 1.0 at% and less than or equal to 7.0 at%, and the sum of the atomic percentages b of P and N elements is 0.4 at% or more, wherein the non-aqueous electrolyte used in a non-aqueous electrolyte battery contains (I-1) a compound represented by the following general formula (1). [In general formula (1), M ａ１＋ is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and a1 represents an integer equal to the valency of the corresponding cation. a1 to d1 represent integers from 1 to 2, and a1 × b1 = c1 × d1. X is a sulfur atom or a phosphorus atom, and if X is a sulfur atom, then m is 2, R ４ It does not exist, and when X is a phosphorus atom, m is 1. １ ~R ４ Each of these is an organic group independently selected from a fluorine atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C2-C10 alkenyl group, a C2-C10 alkenyloxy group, a C2-C10 alkynyl group, a C2-C10 alkynyloxy group, a C3-C10 cycloalkyl group, a C3-C10 cycloalkoxy group, a C3-C10 cycloalkenyl group, a C3-C10 cycloalkenyloxy group, a C6-C10 aryl group, and a C6-C10 aryloxy group, and a fluorine atom, oxygen atom, or unsaturated bond may also be present in the organic group.

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