Cured product, carbon material containing cured product, negative electrode, and non-aqueous secondary battery

Abstract

The present invention pertains to a cured product which comprises a polyoxyalkylene structure and a three-dimensional siloxane structure having a Q unit, and which has a swelling rate in ethyl methyl carbonate of 70 mass% or less.

Description

Technical Field

[0001] This invention relates to a solidified material, a carbon material containing the solidified material, a negative electrode, and a non-aqueous secondary battery.

[0002] Furthermore, the present invention also relates to a composition, a cured product, a method for manufacturing the cured product, a carbon material containing the cured product, a method for manufacturing the carbon material containing the cured product, a method for manufacturing a negative electrode, and a method for manufacturing a secondary battery. Background Technology

[0003] In recent years, with the miniaturization of electronic devices, the demand for high-capacity rechargeable batteries has gradually increased. In particular, rechargeable batteries with higher energy density and superior charge-discharge characteristics, especially lithium-ion rechargeable batteries, have attracted attention compared to nickel-cadmium and nickel-metal hydride batteries.

[0004] As a lithium-ion secondary battery, a non-aqueous lithium secondary battery has been developed, consisting of a positive electrode and a negative electrode capable of absorbing / releasing lithium ions, and a non-aqueous electrolyte containing lithium salts such as LiPF6 and LiBF4, and has been put into practical use.

[0005] As a lithium-ion secondary battery, a non-aqueous lithium secondary battery has been developed, consisting of a positive electrode and a negative electrode capable of absorbing / releasing lithium ions, and a non-aqueous electrolyte containing lithium salts such as LiPF6 and LiBF4, and has been put into practical use.

[0006] Lithium metal was initially used as the negative electrode active material in lithium-ion secondary batteries. However, it was found that dendritic lithium would deposit during repeated charge and discharge cycles, penetrating the separator and reaching the positive electrode, potentially causing a short circuit.

[0007] Therefore, the use of carbon materials that can allow lithium ions to move in and out of the interlayer during charging and discharging and prevent the precipitation of lithium metal as negative electrode active materials is currently attracting attention.

[0008] For example, Patent Document 1 discloses a negative electrode material for lithium secondary batteries, characterized in that, in particles (A) selected from the group consisting of carbon material particles, metal particles and metal oxide particles, two or more different polymer materials are respectively attached to different positions of the particles.

[0009] It can be manufactured with simple processes and can achieve a balanced and excellent range of battery characteristics, such as plate strength, liquid immersion, initial irreversible capacity, high current density charge and discharge characteristics, and cycle retention rate.

[0010] In addition, Patent Document 2 discloses a carbon material coated with a compound formed by cross-linking water-soluble polymers using a silane coupling agent.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: Japanese Patent Application Publication No. 2007-042285

[0014] Patent Document 2: Japanese Patent Application Publication No. 9-161848 Summary of the Invention

[0015] The problem that the invention aims to solve

[0016] When carbon materials such as graphite are used as negative electrode active materials in lithium-ion secondary batteries, it is assumed that lithium ions are inserted from the edges of the graphene structure of the carbon material.

[0017] However, if lithium ions are solvated in the electrolyte, they will embed themselves within the carbon material while remaining solvated, thus disrupting the interlayer structure of graphene. As a result, their function as a negative electrode active material is reduced, and the lifespan of the lithium-ion rechargeable battery is shortened.

[0018] To address this, a method is being considered that involves adding compounds that form a film at the edges of the graphene structure during charging as additives to the electrolyte. This would promote the desolvation of lithium ions during lithium-ion intercalation and improve the durability of the material as a negative electrode active material.

[0019] However, the addition of additives to the electrolyte also has the opposite effect, such as the impact on the positive electrode and the reduction of lithium-ion conductivity in the electrolyte. Therefore, the amount and type of compounds that can be added are limited.

[0020] Therefore, in the aforementioned Patent Document 1, two or more different polymer materials are added to the carbon material particles, thereby improving the durability as a negative electrode active material. On the other hand, the edges of the graphene structure of the carbon material are not easily coated with polymer materials, which needs to be improved from the viewpoint of durability, i.e., stable negative electrode operation.

[0021] Therefore, the first objective of this invention is to provide a carbon material capable of stable negative electrode operation when used as a negative electrode active material in a lithium-ion secondary battery. Furthermore, an objective is to provide a method for manufacturing the carbon material as described above, a method for manufacturing a negative electrode using the aforementioned carbon material, and a method for manufacturing a secondary battery.

[0022] Furthermore, if a carbon material coated with a compound containing a three-dimensional siloxane structure without Q units is used as the negative electrode of a secondary battery, as described in Patent Document 2, there is a problem that the dissolution rate and swelling rate in water and organic solvents cannot be sufficiently reduced. When the dissolution rate in water is high, the following problems arise: when using the coated carbon material to manufacture a slurry in an aqueous system, significant dissolution of components originating from water-soluble polymers occurs from the coating layer, causing the coating layer to peel off and be damaged due to mechanical processing such as mixing. When the dissolution rate in organic solvents is high, the following problems arise: components originating from water-soluble polymers dissolve inside the secondary battery, resulting in poor charge / discharge efficiency and durability due to defects. Furthermore, when the swelling rate in water and organic solvents is high, the following problems arise: when coating the carbon material and manufacturing the secondary battery, a large amount of energy and time is required to remove water and organic solvents from the negative electrode, resulting in poor productivity. In addition, incompletely removed water and organic solvents remain inside the secondary battery during manufacturing, leading to poor charge / discharge efficiency and durability. Assuming a low dissolution rate in water and organic solvents but a high swelling rate in water and organic solvents, the following problems arise: the electrolyte will come into contact with the surface of the carbon material, making it impossible to suppress the decomposition reaction of the electrolyte, resulting in poor durability of the secondary battery.

[0023] Therefore, a second object of the present invention is to provide a cured product capable of sufficiently reducing dissolution rate and swelling rate in water and organic solvents, and a composition for obtaining the cured product.

[0024] Solution for solving the problem

[0025] In order to solve the above-mentioned problems, the inventors have repeatedly conducted in-depth research and found that, for the first objective, if a structure that promotes the desolvation of the electrolyte can be introduced into the edge of the graphene structure of the carbon material, then a stable negative electrode operation can be achieved without the need to add additives to the electrolyte, thereby completing the present invention.

[0026] That is, Scheme A and Scheme B, which are the first principles of the present invention, are as follows.

[0027] Option A

[0028] [A1] A carbon material, which is formed by bonding modifying components to a carbon material raw material, wherein the modifying components include at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur, and germanium, wherein the total atomic concentration of the elements in the carbon material is set as x (atomic %), and the specific surface area of ​​the carbon material is set as y (m²). 2 / g), from x / y (atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 .

[0029] [A2] According to the carbon material described in [A1], the integral area of ​​pores with a diameter less than 1 nm, obtained analytically using the Grand Canonical Monte Carlo (GCMC) method based on molecular simulation, is 0.01 m². 2 / g or less.

[0030] [A3] According to the carbon material described in [A1] or [A2], wherein the total content of the modifying components in the carbon material is less than 1% by volume.

[0031] [A4] The carbon material according to any one of [A1] to [A3], wherein the molecular weight of the modifying component is 500 or less.

[0032] [A5] The carbon material according to any one of [A1] to [A4], wherein the carbon material is composed of x / y (atomic %·g / m). 2 The value represents 0.07–0.8 atoms·g / m 2 .

[0033] [A6] The carbon material according to any one of [A1] to [A5], wherein the raw material of the carbon material comprises at least one of artificial graphite and natural graphite.

[0034] [A7] The carbon material according to [A6], wherein the raw material of the carbon material comprises natural graphite.

[0035] [A8] The carbon material according to any one of [A1] to [A7], wherein the modifying component comprises silicon as the element, and the atomic concentration x(Si) of silicon in the carbon material is 0.1 to 15 atoms.

[0036] [A9] The carbon material according to any one of [A1] to [A8], wherein the specific surface area y of the carbon material is 1 to 15 m². 2 / g.

[0037] [A10] The carbon material according to any one of [A1] to [A9], wherein the Raman R value expressed by the following formula is 0.01 to 0.7.

[0038] Raman R value = (1360 cm⁻¹ in Raman spectroscopy analysis) -1 Nearby peak P B Intensity I B ) / (1580cm in Raman spectroscopy analysis -1 Nearby peak P A Intensity I A )

[0039] [A11] A method for manufacturing a negative electrode, comprising: forming a negative electrode active material layer on a current collector using a carbon material according to any one of [A1] to [A10], thereby obtaining a negative electrode.

[0040] [A12] A method for manufacturing a secondary battery, comprising a positive electrode, a negative electrode, and an electrolyte, comprising: forming a negative electrode active material layer on a current collector using a carbon material according to any one of [A1] to [A10], thereby obtaining the negative electrode.

[0041] Option B

[0042] [B1] A method for manufacturing a carbon material, comprising a carbon material raw material and silicon atoms as a constituent element, comprising: setting the atomic concentration of the silicon atoms in the carbon material as x (atomic %), and setting the specific surface area of ​​the carbon material as y (m²). 2 / g) when x / y (atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 The process of mixing the carbon material raw material and the silicon-containing compound in a certain manner.

[0043] [B2] The method for manufacturing carbon material according to [B1] further includes a step of heating the mixture obtained in the mixing step.

[0044] In order to solve the above-mentioned problems, the inventors have repeatedly conducted in-depth research and found that, for the second objective, the cured product containing a polyoxyalkylene structure and a three-dimensional siloxane structure containing Q units can significantly reduce the dissolution rate and swelling rate in water and organic solvents, thereby completing the present invention.

[0045] That is, the second aspects of the present invention, namely, solutions C, D and E, are as follows.

[0046] Option C

[0047] [C1] A composition comprising a compound (A) and a crosslinked siloxane compound (B), said compound (A) comprising a polyoxyalkylene structure, said crosslinked siloxane compound (B) comprising a Q unit, said compound (A) having at least two crosslinked silicon units in one molecule.

[0048] [C2] The composition according to [C1], wherein the polyoxyalkylene structure in the composition is present in an amount of 10% to 60% by mass.

[0049] [C3] The composition according to [C1] or [C2], wherein the total content of the Q units in the composition is 10% to 50% by mass.

[0050] [C4] The composition according to any one of [C1] to [C3], wherein the compound (A) comprises a crosslinked silicon unit.

[0051] [C5] The composition according to any one of [C1] to [C4], wherein the composition further comprises a solvent.

[0052] [C6] The composition according to any one of [C1] to [C5], wherein the composition further comprises a boron-containing compound (C).

[0053] [C7] The composition according to any one of [C1] to [C6], wherein the composition is a thermosetting composition.

[0054] Plan D

[0055] [D1] A cured product comprising a polyoxyalkylene structure and a three-dimensional siloxane structure having Q units, said cured product having a swelling rate of less than 70% by mass in ethyl methyl carbonate.

[0056] [D2] According to the cured product of [D1], wherein the content of the polyoxyalkylene structure in the cured product is 20% to 80% by mass.

[0057] [D3] The cured product according to [D1] or [D2], wherein the silicon atom content in the cured product is 10% to 40% by mass.

[0058] [D4] The cured product according to any one of [D1] to [D3], wherein the total content of the Q units in the cured product is 20% to 60% by mass.

[0059] [D5] The cured product according to any one of [D1] to [D4], wherein, after hydrolysis, the cured product comprises a polyoxyalkylene structure and a segment having at least two silicon atoms in one molecule.

[0060] [D6] A carbon material containing a solidified material, comprising a solidified material and a carbon material according to any one of [D1] to [D5].

[0061] [D7] According to the carbon material containing the solidified product as described in [D6], wherein the carbon material has a modifying component bonded to the carbon material raw material, the modifying component comprising at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur and germanium.

[0062] [D8] According to the carbon material containing the solidified material described in [D7], wherein the modifying component has bonding sites capable of bonding with the carbon material.

[0063] [D9] The carbon material containing the cured material according to [D7] or [D8], wherein the molecular weight of the modifying component is 500 or less.

[0064] [D10] The carbon material containing a cured product according to any one of [D7] to [D9], wherein the modifying component is represented by the following general formula (1).

[0065] (Z) n -LW(1)

[0066] (In general formula (1), Z is a group that can chemically bond with carbon materials, W is a group that contains at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur and germanium, L is a linker, and n is 1 or 2.)

[0067] [D11] According to the carbon material containing the solidified material described in [D10], wherein in the general formula (1), W is a group containing silicon.

[0068] [D12] According to the carbon material containing the solidified material described in [D10] or [D11], wherein Z in the general formula (1) contains a structure that can be added by the Diels-Alder reaction.

[0069] [D13] The carbon material containing a cured product according to any one of [D10] to [D12], wherein Z in the general formula (1) is a group containing an unsaturated bond at the end.

[0070] [D14] The carbon material containing a cured product according to any one of [D10] to [D13], wherein Z in the general formula (1) is a vinyl group.

[0071] [D15] The carbon material containing a cured product according to any one of [D6] to [D14], wherein the surface of the carbon material comprises carbon-carbon unsaturated bonds and carbon free radical structures.

[0072] [D16] A negative electrode comprising a carbon material containing a solidified material according to any one of [D6] to [D15].

[0073] [D17] A non-aqueous secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the positive and negative electrodes are capable of absorbing and releasing lithium ions, and the negative electrode comprises a carbon material containing a solidified material according to any one of [D6] to [D15].

[0074] Plan E

[0075] [E1] A method for manufacturing a cured product, wherein the composition according to any one of [C1] to [C7] is heated.

[0076] [E2] A method for manufacturing a carbon material containing a solidified material, wherein the composition according to any one of [C1] to [C7] is heated in the presence of the carbon material.

[0077] [E3] According to the method for manufacturing carbon material containing solidified material as described in [E2], wherein the carbon material containing solidified material is used as a negative electrode active material.

[0078] [E4] A method for manufacturing a negative electrode, comprising: forming a negative electrode active material layer on a current collector using a carbon material containing a solidified material obtained by the manufacturing method according to [E3], thereby obtaining a negative electrode.

[0079] [E5] A method for manufacturing a secondary battery, comprising a positive electrode, a negative electrode, and an electrolyte, comprising: forming a negative electrode active material layer on a current collector using a carbon material containing a solidified material obtained by the manufacturing method according to [E3], thereby obtaining the negative electrode.

[0080] Furthermore, the solution F, which addresses the first and second objectives of the present invention and serves as the third objective of the present invention, is as follows.

[0081] Plan F

[0082] [F1] A method for modifying a carbon material, comprising: a step of bonding a modifying component to the carbon material.

[0083] [F2] According to the modification method described in [F1], the modifying component comprises at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus and germanium.

[0084] [F3] According to the modification method described in [F1] or [F2], wherein the modifying component has a bonding site capable of bonding with a carbon material.

[0085] [F4] The modification method according to any one of [F1] to [F3], wherein the molecular weight of the modifying component is 500 or less.

[0086] [F5] The modification method according to any one of [F1] to [F4], wherein the modification component is represented by the following general formula (1).

[0087] (Z) n -LW(1)

[0088] (In general formula (1), Z is a group that can chemically bond with carbon materials, W is a group that contains at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur and germanium, L is a linker, and n is 1 or 2.)

[0089] [F6] According to the modification method described in [F5], in the general formula (1), W is a group containing silicon.

[0090] [F7] According to the modification method described in [F5] or [F6], wherein Z in the general formula (1) contains a structure that can be added via the Diels-Alder reaction.

[0091] [F8] The modification method according to any one of [F5] to [F7], wherein Z in the general formula (1) is a group containing an unsaturated bond at the end.

[0092] [F9] The modification method according to any one of [F5] to [F8], wherein Z in the general formula (1) is vinyl.

[0093] [F10] The modification method according to any one of [F1] to [F9], wherein the surface of the carbon material comprises carbon-carbon unsaturated bonds and carbon free radical structures.

[0094] [F11] The modification method according to any one of [F1] to [F10], wherein the step of bonding the modifying component to the carbon material includes physically contacting the carbon material with the modifying component.

[0095] [F12] The modification method according to any one of [F1] to [F11] further includes heating at 120°C or higher.

[0096] [F13] The modification method according to any one of [F1] to [F12] includes a step of further contacting a polymer with a carbon material obtained after the step of bonding the modification component with the carbon material, the polymer comprising at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur and germanium.

[0097] [F14] The modification method according to [F13] further includes heating to a temperature of 120°C or higher.

[0098] [F15] A modification method comprising: contacting a polymer with a carbon material bonded with a modifying component, said polymer comprising at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur and germanium.

[0099] [F16] The modification method according to [F15] further includes heating to a temperature of 120°C or higher.

[0100] Invention Effects

[0101] Regarding the first objective mentioned above, the carbon material of the present invention, when used as a negative electrode active material in a lithium-ion secondary battery, can perform stable negative electrode operation, maintain good initial discharge capacity, and achieve high initial efficiency. Furthermore, the manufacturing method of the carbon material of the present invention can obtain the excellent carbon material described above.

[0102] Furthermore, by means of the method for manufacturing the negative electrode and the method for manufacturing the secondary battery of the present invention, it is possible to obtain an excellent negative electrode and a secondary battery that contain the excellent carbon material as described above as the negative electrode active material.

[0103] Regarding the second objective mentioned above, the cured product of the present invention can sufficiently reduce the dissolution rate and swelling rate in water and organic solvents. Furthermore, the composition of the present invention can yield a cured product that can sufficiently reduce the dissolution rate and swelling rate in water and organic solvents. Detailed Implementation

[0104] The present invention will now be described in detail, but it is not limited to the embodiments described below, and various modifications can be made within its scope. It should be noted that when the term "~" is used in this specification, it is used to indicate the numerical or physical property values ​​preceding or following it. Furthermore, mass% and weight% and parts by mass and parts by weight have the same meaning.

[0105] Carbon Materials

[0106] To achieve the first objective described above, it is preferable that the carbon material of this embodiment has a modifying component bonded to the carbon material raw material. The modifying component includes at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur, and germanium (hereinafter, sometimes referred to as "the constitutive element of the modifying component").

[0107] Let the total atomic concentration of the constituent elements of the above-mentioned modifying components in the carbon material be x (atomic %), and the specific surface area of ​​the carbon material be y (m²). 2 / g), from x / y (atomic %·g / m) 2 The value represented by ) is preferably 0.05 to 1 atom%·g / m 2 .

[0108] In this embodiment, where the modifying component includes silicon, the carbon material of this embodiment comprises a carbon material raw material and silicon atoms as constitutive elements. Furthermore, the atomic concentration of silicon atoms in the carbon material is set to x. (Si) (atomic %), the specific surface area of ​​carbon materials is set as y(m2 When / g), by x (Si) / y(atomic %·g / m) 2 The value represented by ) is preferably 0.05 to 1 atom%·g / m 2 More preferably, it is 0.07–0.8 atomic percent·g / m 2 More preferably 0.3 to 1 atomic percent g / m 2 .

[0109] Carbon materials, by incorporating silicon atoms as constituent elements, can enable the edges of graphene structures in carbon material raw materials to become structures that promote the desolvation of lithium ions solubilized in the electrolyte in lithium-ion secondary batteries.

[0110] The exact reason is still uncertain, but silicon atoms can form covalent bonds with carbon atoms, thus easily forming strong bonds at the edges of graphene structures in carbon materials. Furthermore, as a result of this bonding, the electrochemically active graphene structures at the edges are replaced by less reactive silicon oxide. Therefore, lithium ions solubilized with the electrolyte in lithium-ion secondary batteries are easily solubilized at these edges in a state where side reactions are suppressed. Consequently, it is believed that side reactions on the surface of carbon materials and the destruction of the interlayer structure within the graphene can be suppressed.

[0111] Furthermore, in the case where the modifying component in this embodiment includes aluminum, the carbon material of this embodiment comprises a carbon material raw material and aluminum atoms as constitutive elements. Furthermore, the atomic concentration of aluminum atoms in the carbon material is set as x. (Al) (atomic %), the specific surface area of ​​carbon materials is set as y(m 2 When / g), by x (Al) / y(atomic %·g / m) 2 The value represented by ) is preferably 0.05 to 1 atom%·g / m 2 .

[0112] Carbon materials, by including aluminum atoms as constituent elements, can create structures at the edges of graphene structures in carbon material raw materials that promote the desolvation of lithium ions solubilized in the electrolyte in lithium-ion secondary batteries.

[0113] The exact reasons are still uncertain, but aluminum atoms possess the property of sol-gelling due to acidification of halides and alkoxy compounds, thus readily bonding with acidic functional groups at the edges of graphene structures derived from carbon materials. Furthermore, the chemically stable aluminum suppresses the reactivity of the electrochemically active graphene structure at the edges, allowing lithium ions solubilized in the electrolyte in lithium-ion secondary batteries to easily desolvate at these edges, even when side reactions with the electrolyte are suppressed. As a result, it is believed that side reactions on the carbon material surface and the destruction of the interlayer interior of the graphene structure can be suppressed.

[0114] In this embodiment, x / y (atomic %·g / m) 2 The value represented by ) indicates the total atomic concentration x (atomic %) of the constituent elements of the modifying components in the carbon material relative to the specific surface area y (m²) of the carbon material. 2 The ratio of / g) is given by a value of 0.05 atomic %·g / m. 2 The above appropriately demonstrates the reduction effect of side reactions obtained from the aforementioned modified components. Furthermore, by using x / y (atomic %·g / m) 2 The value represented is 1 atom %·g / m 2 The following method can suppress the increase in lithium-ion mobility resistance caused by the modified components.

[0115] It should be noted that, in this specification, the atomic concentration x (atomic %) of the constituent elements of the modifying components in the carbon material is a value determined by X-ray photoelectron spectroscopy (XPS), specifically, a value determined under the conditions described in the examples described later.

[0116] In addition, the specific surface area y(m) of carbon materials 2 The value ( / g) is obtained by the nitrogen adsorption BET single-point method based on the results of nitrogen adsorption-desorption determination obtained by gas flow method, specifically, the value determined under the conditions described in the examples described later.

[0117] In this embodiment, x / y (atomic %·g / m) 2 The value represented by ) is preferably 0.05 to 1 atom%·g / m 2 More preferably, it is 0.07–0.8 atomic percent·g / m 2 More preferably 0.3 to 1 atomic percent g / m 2 From the viewpoint of reducing side reactions, the above value is preferably 0.05 atomic %·g / m 2 The above, more preferably 0.07 atomic percent g / m 2 The above is further preferably 0.1 atomic percent g / m 2 The above is further preferred to be 0.15 atomic percent g / m 2 The above can also be 0.3 atomic percent g / m 2 The above can also be 0.4 atomic %·g / m 2 The above can also be 0.5 atomic percent g / m 2 That's all. Furthermore, from the viewpoint of suppressing the increase in resistance, the above value is preferably 1 atom%·g / m 2 Hereinafter, 0.9 atomic percent g / m is preferred. 2Hereinafter, 0.8 atomic percent g / m is further preferred. 2 the following.

[0118] In this embodiment, x (Si) / y(atomic %·g / m) 2 The value represented by ) is preferably 0.05 to 1 atom%·g / m 2 More preferably, it is 0.07–0.8 atomic percent·g / m 2 More preferably 0.3 to 1 atomic percent g / m 2 From the viewpoint of reducing side reactions, the above value is preferably 0.05 atomic %·g / m 2 The above, more preferably 0.07 atomic percent g / m 2 The above, more preferably 0.3 atomic percent g / m 2 The above is further preferably 0.4 atomic percent g / m 2 The above is further preferred to be 0.5 atomic percent g / m 2 That's all. Furthermore, from the viewpoint of suppressing the increase in resistance, the above value is preferably 1 atom%·g / m 2 Hereinafter, 0.9 atomic percent g / m is preferred. 2 Hereinafter, 0.8 atomic percent g / m is further preferred. 2 the following.

[0119] In this embodiment, x (Al) / y(atomic %·g / m) 2 The value represented by ) is preferably 0.05 to 1 atom%·g / m 2 From the viewpoint of reducing side reactions, the above value is preferably 0.05 atomic %·g / m 2 The above, more preferably 0.07 atomic percent g / m 2 The above is further preferably 0.1 atomic percent g / m 2 The above is further preferred to be 0.15 atomic percent g / m 2 That's all. Furthermore, from the viewpoint of suppressing the increase in resistance, the above value is preferably 1 atom%·g / m 2 Hereinafter, 0.9 atomic percent g / m is preferred. 2 Hereinafter, 0.8 atomic percent g / m is further preferred. 2 the following.

[0120] The total atomic concentration x (atomic %) of the constituent elements of the modifying components in the carbon material of this embodiment is preferably 0.1 to 15 atomic %, more preferably 0.2 to 10 atomic %, and even more preferably 0.3 to 5 atomic %. From the viewpoint of reducing side reactions, the atomic concentration x (atomic %) is preferably 0.1 atomic % or more, more preferably 0.2 atomic % or more, and even more preferably 0.3 atomic % or more. Furthermore, from the viewpoint of suppressing resistance increase, the atomic concentration x (atomic %) is preferably 15 atomic % or less, more preferably 10 atomic % or less, and even more preferably 5 atomic % or less.

[0121] In this embodiment, it is more preferable to use x / y (atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 And the atomic concentration x (atomic %) is 0.1 to 15 atomic %.

[0122] The atomic concentration x of silicon atoms in the carbon material of this embodiment (Si) The atomic concentration (%) is preferably 0.1 to 15 atomic%, more preferably 0.2 to 10 atomic%, and even more preferably 0.3 to 5 atomic%. Here, from the viewpoint of reducing side reactions, the above atomic concentration x... (Si) The atomic percentage (%) is preferably 0.1 atomic% or more, more preferably 0.2 atomic% or more, and even more preferably 0.3 atomic% or more. Furthermore, from the viewpoint of suppressing the increase in resistance, the above atomic concentration x... (Si) The atomic percentage is preferably 15 atomic percent or less, more preferably 10 atomic percent or less, and even more preferably 5 atomic percent or less.

[0123] The atomic concentration x of aluminum atoms in the carbon material of this embodiment (Al) The atomic concentration (%) is preferably 0.1 to 15 atomic%, more preferably 0.2 to 10 atomic%, and even more preferably 0.3 to 5 atomic%. Here, from the viewpoint of reducing side reactions, the above atomic concentration x... (Al) The atomic concentration (atomic %) is preferably 0.1 atomic % or more, more preferably 0.2 atomic % or more, and even more preferably 0.3 atomic % or more. Furthermore, from the viewpoint of suppressing the increase in resistance, the atomic concentration x (atomic %) is preferably 15 atomic % or less, more preferably 10 atomic % or less, and even more preferably 5 atomic % or less.

[0124] The specific surface area y(m²) of the carbon material in this embodiment 2 / g) is preferably 1-15m 2 / g, more preferably 1.2 to 10m 2 / g, more preferably 1.4–5m 2 / g. Here, from the viewpoint of ensuring sufficient sites for lithium-ion insertion / extraction to obtain good high-speed charge / discharge characteristics and output characteristics, the above specific surface area y (m²) is considered... 2 / g) is preferably 1m 2 / g or more, preferably 1.2m 2 / g or more, further preferably 1.4m 2 / g or more. Furthermore, from the viewpoint of appropriately suppressing the activity of the negative electrode active material on the electrolyte, suppressing the increase in initial irreversible capacity, and achieving high capacity, the above specific surface area y (m²) is considered... 2 / g) is preferably 15m 2 / g or less, more preferably 10m 2 / g or less, more preferably 5m 2 / g or less.

[0125] In this embodiment, it is more preferable to use x / y (atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 And specific surface area y(m 2 / g) is 1~15m 2 / g. Furthermore, even more preferably, the atomic concentration x (atomic %) is 0.1–15 atomic %, and the specific surface area y (m²) is... 2 / g) is 1~15m 2 / g. Furthermore, it is even more preferred that x / y (atomic %·g / m) is used. 2 The value represented is 0.05 to 1 atom %·g / m 2 The atomic concentration x (atomic %) is 0.1–15 atomic %, and the specific surface area y (m²) is... 2 / g) is 1~15m 2 / g.

[0126] The carbon material of this embodiment preferably contains phosphorus atoms as a modifying component, more preferably it contains phosphorus atoms in addition to aluminum atoms as a modifying component, and even more preferably the atomic concentration of phosphorus atoms in the carbon material is 0.1 to 1 when the atomic concentration of aluminum atoms in the carbon material is set to 1. Therefore, when the carbon material of this embodiment is used as the negative electrode active material of a lithium-ion secondary battery, a higher initial efficiency can be achieved.

[0127] The reason why the initial efficiency is further improved by including phosphorus atoms in addition to aluminum atoms as constituent elements is still uncertain, but it is believed to be as follows.

[0128] It is believed that aluminum phosphate is locally generated through the reaction of phosphoric acid and aluminum, and that the high chemical stability and the micropores formed enable more stable desolvation.

[0129] When the atomic concentration of aluminum atoms in the carbon material is set to 1, the atomic concentration ratio of phosphorus atoms in the carbon material, i.e., the phosphorus atom concentration ratio, is preferably 0.1 to 1, more preferably 0.15 to 0.95, and even more preferably 0.2 to 0.9. From the viewpoint of appropriately obtaining the effect of including phosphorus atoms, the above-mentioned phosphorus atom concentration ratio is preferably 0.1 or more, more preferably 0.15 or more, and even more preferably 0.2 or more. Furthermore, from the viewpoint of suppressing the increase in battery resistance, the above-mentioned phosphorus atom concentration ratio is preferably 1 or less, more preferably 0.95 or less, and even more preferably 0.9 or less.

[0130] Furthermore, the preferred range of the atomic concentration of phosphorus atoms in the carbon material varies depending on the atomic concentration of aluminum atoms in the carbon material, for example, preferably 0.01 to 15 atomic%, more preferably 0.02 to 10 atomic%, and even more preferably 0.03 to 5 atomic%. Here, from the viewpoint of appropriately obtaining the effect obtained by including phosphorus atoms, the above-mentioned atomic concentration of phosphorus atoms is preferably 0.01 atomic% or more, more preferably 0.02 atomic% or more, and even more preferably 0.03 atomic% or more. Furthermore, from the viewpoint of potential capacity, the above-mentioned atomic concentration of phosphorus atoms is preferably 15 atomic% or less, more preferably 10 atomic% or less, and even more preferably 5 atomic% or less.

[0131] In this embodiment, the carbon material's micropore distribution was analytically determined using the Grand Canonical Monte Carlo (GCMC) method of molecular simulation, and the integral area of ​​the micropores with a diameter of less than 1 nm is preferably 0.01 m². 2 / g or less.

[0132] Here, the adsorption simulation using the GCMC method of molecular simulation is a method to simulate the adsorption amount under a certain pressure for a specific pore size. Specifically, the interaction parameters such as pore size, pore shape, adsorbed molecules, and surface atoms of the adsorbent material are determined. The adsorbed molecules are actually placed into the imaginary space of the pore, and the movement, generation, and disappearance of adsorbed molecules are observed. Then, the operation is repeated: if the energy of the system is negative (stable), it is accepted; otherwise, it is restored, and the adsorption amount as described above is obtained.

[0133] By selecting a microporous structure (slit, cylinder, cage) and determining the parameters of the adsorbate / adsorbent material, theoretical adsorption isotherms for various micropore sizes are derived using GCMC. The isotherms obtained by integrating these theoretical isotherms are then fitted to the measured isotherms to calculate the micropore distribution curve with the smallest error in adsorption capacity. This allows for the analysis of micropore distribution across the entire range from micropores to mesopores.

[0134] The parameters of the interactions between N2 molecules and the interactions between graphite and N2 molecules can be, for example, determined by Sweatman, MB, et al., “J. Phys. Chem., 105, 1403 (2001)”.

[0135] Specifically, BELSORP MINIII was prepared using MicrotracBEL to determine the N2 adsorption isotherm, and BELMasterT was analyzed by the analysis rate under the following conditions.

[0136] Measurement: MicrotracBEL automatic surface area / pore distribution measuring device BELSORP MINIII.

[0137] Measurement temperature: 77K.

[0138] Adsorbate: N2.

[0139] Pretreatment conditions: 100℃ for 3 hours.

[0140] Analysis: BELMasterTM V6.3.00.

[0141] Distribution function: No-assumption.

[0142] Pore ​​size definition: Pore size defined for solids and liquids (Solid and Fluid def. PoreSize).

[0143] Model: GCMC.

[0144] Fine-pore structure: slit.

[0145] Adsorbent: C.

[0146] From the perspective of suppressing electrolyte decomposition, the integral area of ​​pores with a diameter of less than 1 nm, obtained using the above GCMC method, is preferably 0.01 μm. 2 / g or less, preferably 0m 2 / g.

[0147] Furthermore, from the viewpoint of suppressing electrolyte decomposition, the integral area of ​​pores with a diameter of less than 1.5 nm obtained using the above GCMC method is preferably 0.01 μm. 2 / g or less, preferably 0m 2 / g.

[0148] The Raman R value of the carbon material in this embodiment is preferably 0.01 to 0.7, more preferably 0.02 to 0.65, and even more preferably 0.03 to 0.6. From the viewpoint that high-density materials are less prone to surface orientation and thus avoid a decrease in non-chargeable / dischargeable properties, the Raman R value is preferably 0.01 or higher, more preferably 0.02 or higher, and even more preferably 0.03 or higher. Furthermore, from the viewpoint of suppressing the increase in irreversible capacity as the negative electrode active material, thereby obtaining good initial efficiency and long-term storage recovery rate, and from the viewpoint of suppressing excessive reaction with the electrolyte, preventing a decrease in charge / discharge efficiency and an increase in gas generation, the Raman R value is preferably 0.7 or lower, more preferably 0.65 or lower, and even more preferably 0.6 or lower.

[0149] The Raman R value of carbon materials can be adjusted by factors such as the content of amorphous carbon materials in the raw materials and the heating temperature during the manufacturing of the raw materials.

[0150] It should be noted that the Raman R value in this specification refers to the value expressed by the following formula.

[0151] Raman R value = (1360 cm⁻¹ in Raman spectroscopy analysis) -1 Nearby peak P B Intensity I B ) / (1580cm in Raman spectroscopy analysis -1 Nearby peak P A Intensity I A )

[0152] In the above formula, "1580cm" -1 "Nearby" refers to 1580cm -1 ~1620cm -1 The range. Furthermore, "1360cm" -1 "Nearby" refers to 1350cm -1 ~1370cm -1 The range.

[0153] Here, 1580cm -1 Nearby peak P A This refers to the peak known as the G-band, originating from the graphite structure, at 1360 cm⁻¹. -1 Nearby peak P B It refers to the peak known as the D band that appears when the symmetry is disrupted due to the introduction of defects.

[0154] By using these Raman R values, the crystal purity and defect ratio of carbon materials can be evaluated.

[0155] Raman spectroscopy is obtained by measuring using a Raman spectrometer.

[0156] Specifically, carbon material is allowed to fall naturally into the measuring container, which is then irradiated with an argon ion laser while the container is rotated in a plane perpendicular to the laser. The measuring conditions are as follows.

[0157] The wavelength of the argon ion laser is 514.5 nm.

[0158] Laser power on the sample: 25mW.

[0159] Resolution: 4cm -1 .

[0160] Measurement range: 1100cm -1 ~1730cm -1 .

[0161] Peak intensity measurement, peak half-width measurement: background processing, smoothing processing (based on simple averaging convolution of 5 points).

[0162] The surface functional group content of the carbon material in this embodiment, specifically the O / C value representing the surface oxygen concentration, is preferably 0.01% to 4%, more preferably 0.1% to 4%, further preferably 0.3% to 3.6%, and even more preferably 0.5% to 3%. From the viewpoint of enhancing the interaction between the carbon material surface and organic compounds and preventing the stripping of organic compounds, the aforementioned surface functional group content O / C value is preferably 0.01% or more, more preferably 0.1% or more, further preferably 0.3% or more, and particularly preferably 0.5% or more. Furthermore, from the viewpoint of facilitating the adjustment of the O / C value using oxidation treatments, etc., thereby increasing productivity and reducing costs, the aforementioned surface functional group content O / C value is preferably 4% or less, more preferably 3.6% or less, and even more preferably 3% or less.

[0163] In this embodiment, the average particle size d50 of the carbon material based on volume is preferably 1 to 50 μm, more preferably 4 to 30 μm, and even more preferably 6 to 25 μm. From the viewpoint that the specific surface area will not become too large and suppress the activity to the electrolyte, the aforementioned average particle size d50 is generally 1 μm or more, preferably 4 μm or more, and more preferably 6 μm or more. Furthermore, from the viewpoint of suppressing process defects such as stripe formation during electrodeposition, the aforementioned average particle size d50 is generally 50 μm or less, preferably 30 μm or less, and more preferably 25 μm or less.

[0164] The average particle size d50 of the volume reference for carbon materials is the value of the median particle size of the volume reference, which is determined using a laser diffraction / scattering particle size distribution measuring device. It can be adjusted, for example, by crushing, breaking, or classifying.

[0165] The aspect ratio of the carbon material in this embodiment is preferably 1 to 10, more preferably 1.1 to 8, even more preferably 1.1 to 5, and even more preferably 1.2 to 3. Theoretically, an aspect ratio of 1 or more is desirable. From the viewpoint of minimizing the formation of stripes during electrodeation, obtaining a uniform coating surface, and achieving good high-current-density charge-discharge characteristics, the aspect ratio is preferably 1.1 or more, more preferably 1.2 or more. Furthermore, from the same viewpoint, the aspect ratio is preferably 10 or less, more preferably 8 or less, even more preferably 5 or less, and particularly preferably 3 or less.

[0166] The pore volume of the carbon material in this embodiment, ranging from 10 nm to 1000 nm, is preferably 0.05 to 0.3 mL / g, more preferably 0.07 to 0.28 mL / g, and even more preferably 0.1 to 0.25 mL / g. From the viewpoint of lithium metal deposition and electrode strength during fast charging, the aforementioned pore volume is preferably 0.05 mL / g or more, more preferably 0.07 mL / g or more, and even more preferably 0.1 mL / g or more. Furthermore, from the same viewpoint, the aforementioned pore volume is preferably 0.3 mL / g or less, more preferably 0.28 mL / g or less, and even more preferably 0.25 mL / g or less.

[0167] It should be noted that the pore volume in the range of 10nm to 1000nm mentioned above is a value determined by mercury porosimetry using a mercury porosimeter.

[0168] The total micropore volume of the carbon material in this embodiment is preferably 0.1 to 10 mL / g, more preferably 0.2 to 5 mL / g, even more preferably 0.25 to 2 mL / g, and even more preferably 0.5 to 1 mL / g. From the viewpoint of dispersing the thickener and binder during electrodeization, the above-mentioned total micropore volume is preferably 0.1 mL / g or more, more preferably 0.2 mL / g or more, even more preferably 0.25 mL / g or more, and even more preferably 0.5 mL / g or more. Furthermore, from the same viewpoint, the above-mentioned total micropore volume is preferably 10 mL / g or less, more preferably 5 mL / g or less, even more preferably 2 mL / g or less, and even more preferably 1 mL / g or less.

[0169] The total pore volume mentioned above can be adjusted by heating the carbon material.

[0170] It should be noted that the total micropore volume in this instruction manual is a value determined by mercury porosimetry using a mercury porosimeter.

[0171] The average pore size of the carbon material in this embodiment is preferably 0.03 to 80 μm, more preferably 0.05 to 50 μm, even more preferably 0.1 to 50 μm, and even more preferably 0.5 to 20 μm. From the viewpoint of the amount of binder during electrodeization and the high current density charge-discharge characteristics of the battery, the aforementioned average pore size is preferably 0.03 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and even more preferably 0.5 μm or more. Furthermore, from the same viewpoint, the aforementioned average pore size is preferably 80 μm or less, more preferably 50 μm or less, and even more preferably 20 μm or less.

[0172] The tap density of the carbon material in this embodiment is typically 0.1–1.3 g / cm³. 3 Preferably, it is 0.15–1.2 g / cm³. 3 More preferably, it is 0.2–1.2 g / cm³. 3 More preferably, it is 0.3–1.1 g / cm³. 3 From the perspective of obtaining good high-speed charge and discharge characteristics, the aforementioned tap density is typically 0.1 g / cm³. 3 The above is preferably 0.15 g / cm³. 3 The above, more preferably 0.2 g / cm 3 The above is further preferred to be 0.3 g / cm³. 3 That's all. Furthermore, from the viewpoint of suppressing the increase in carbon density within the particles and suppressing the decrease in calendering properties to obtain a high-density negative electrode, the aforementioned tap density is typically 1.3 g / cm³. 3 The preferred value is 1.2 g / cm³. 3 The following is more preferably 1.1 g / cm³ 3 the following.

[0173] It should be noted that the tap density in this instruction manual is measured using a powder density meter, with the sample filling a 1.6 cm diameter, 20 cm³ volumetric sphere. 3 After compacting the cylindrical vibratory container, the sample was compacted under the conditions of a stroke length of 10 mm and 1000 vibrations. The density value was calculated based on the volume and mass of the sample at this time.

[0174] <Carbon Material Raw Materials>

[0175] The carbon material in this embodiment preferably has a modifying component bonded to the carbon material raw material, and preferably includes at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur and germanium as the constituent element of the carbon material raw material and the modifying component.

[0176] Here, it is more preferable to include silicon or aluminum as constituent elements of the above-mentioned modifying components. In the case of aluminum, it is even more preferable to include phosphorus as a constituent element of the above-mentioned modifying components.

[0177] The carbon material raw material used in this embodiment is not particularly limited. Carbon material raw materials of various degrees of graphitization, ranging from graphite to amorphous raw materials, can be used. One type can be used alone, or two or more types can be used in combination.

[0178] From a commercially available perspective, the carbon material raw material preferably includes at least one of graphite and amorphous carbon with low graphitization, and more preferably includes graphite. The aforementioned graphite and amorphous carbon are also preferred from the viewpoint of charge-discharge characteristics at high current densities.

[0179] In this embodiment, the graphite content in the carbon material raw material is preferably 90-100% by mass, more preferably 95-99% by mass. The type and content of graphite in the carbon material raw material can be appropriately adjusted in a way that can achieve the desired physical properties such as d002 value as a carbon material.

[0180] In this embodiment, when the carbon material raw material includes graphite, the carbon material raw material preferably includes at least one of artificial graphite and natural graphite. From the viewpoint of large specific surface area and improved initial efficiency, it is more preferable to include natural graphite. From the viewpoint of recycling characteristics, it is more preferable to include artificial graphite.

[0181] As for graphite, graphite with fewer impurities is preferred, and it can also be used after various purification treatments as needed.

[0182] Examples of natural graphite include earthy graphite, scaly graphite, and flake graphite. Among these, scaly graphite and flake graphite are preferred from the viewpoint of high graphitization and low impurity content, with flake graphite being more preferred. Furthermore, from the viewpoint of particle filling properties and charge / discharge load characteristics obtained by forming appropriately dense pores within the carbon material, spherical natural graphite is preferable.

[0183] Examples of artificial graphite include substances obtained by heating organic materials such as coal tar pitch, coal-based heavy oil, atmospheric residue oil, petroleum-based heavy oil, aromatic hydrocarbons, nitrogen-containing cyclic compounds, sulfur-containing cyclic compounds, polystyrene, polyvinyl chloride, polyvinyl alcohol, polyacrylonitrile, polyvinyl butyral, natural polymers, polyphenylene sulfide, polyphenylene ether, furfuryl alcohol resin, phenolic resin, and imide resin to above 2500°C for graphitization.

[0184] In this embodiment, the carbon material raw material is preferably one that allows the obtained carbon material to meet the desired physical properties.

[0185] For example, considering that the Raman R value of the carbon material raw material and the obtained carbon material should be the same, if it is desired to obtain a carbon material with a Raman R value of 0.01 to 0.7, it is preferable to use a carbon material raw material whose Raman R value is also 0.01 to 0.7. That is, the Raman R value of the carbon material raw material is preferably 0.01 to 0.7, more preferably 0.02 to 0.65, and even more preferably 0.03 to 0.6. Here, for the obtained carbon material, from the viewpoint that the crystal is less likely to be oriented along the plane under high density, thus avoiding a decrease in non-chargeable and non-dischargeable characteristics, the above-mentioned Raman R value is preferably 0.01 or more, more preferably 0.02 or more, and even more preferably 0.03 or more. Furthermore, considering the viewpoints of suppressing the increase in irreversible capacity as a negative electrode active material to obtain good initial efficiency and long-term storage recovery rate, and suppressing excessive reaction with electrolyte to prevent the decrease in charge and discharge efficiency and the increase in gas generation, the Raman R value is preferably 0.7 or less, preferably 0.65 or less, and more preferably 0.6 or less.

[0186] The Raman R value of carbon material raw materials can be adjusted by the content of amorphous carbon materials and the heating temperature during the manufacturing of carbon material raw materials.

[0187] <Modifying Ingredients>

[0188] The modifying component in this embodiment preferably includes at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur, and germanium, and more preferably has a bonding site capable of bonding with carbon materials.

[0189] In addition, carbon materials are typically manufactured using methods described later in order to control the reactivity of the modifying components.

[0190] The molecular weight of the above-mentioned modified component is preferably 500 or less, and more preferably a structure represented by the following formula (1).

[0191] (Z) n -LW(1)

[0192] (In general formula (1), Z is a group that can chemically bond with carbon materials, W is a group that contains at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur and germanium, L is a linker, and n is 1 or 2.)

[0193] Furthermore, the total content of the modifying components in the carbon material of this embodiment is typically less than 1% by volume.

[0194] • Sites capable of chemically bonding with carbon materials

[0195] The surface structures of carbon materials can include structures containing carbon-carbon unsaturated bonds and carbon free radical structures. In the above general formula (1), Z can be any group that forms a bond with them, without any particular restriction, and known groups can be used.

[0196] From the viewpoint that it can form a bond with a structure containing carbon-carbon unsaturated bonds in the surface structure of carbon materials, Z in the above general formula (1) preferably contains a structure that can be added by the Diels-Alder reaction, more preferably a group having an unsaturated bond at the end, and even more preferably a vinyl group.

[0197] Silicon atoms

[0198] In this embodiment, silicon atoms, which are constituent elements of the carbon material and serve as modifying components, are introduced by reacting a silicon-containing compound with the carbon material raw material.

[0199] Silicon atoms are present on the surface of carbon materials through bonding between silicon atoms and carbon atoms in the raw materials, and silicon atoms are also present at the edges of the graphene structure within the carbon materials. Therefore, for solvated lithium ions to be embedded at the edges of the graphene structure, desolvation can be promoted while suppressing side reactions.

[0200] The atomic concentration x of silicon atoms in the carbon material of this embodiment (Si) (atomic %) is preferably the above-mentioned composition of x (Si) / y(atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 Such a value is more preferably the one described above, which is derived from x. (Si) / y(atomic %·g / m) 2 The value represented is 0.07–0.8 atomic %·g / m 2 The value of .

[0201] The atomic concentration x of the aforementioned silicon atoms (Si) (Atomic percentage) can be adjusted by increasing or decreasing the amount of silicon-containing compound added when mixed with carbon material raw materials.

[0202] Aluminum atoms

[0203] In this embodiment, aluminum atoms, which are constituent elements of the carbon material and serve as modifying components, are introduced by reacting an aluminum-containing compound directly or indirectly with the carbon material raw material.

[0204] Aluminum atoms are present on the surface of the carbon material raw material through bonding between aluminum atoms and carbon atoms in the raw material, and aluminum atoms are also present at the edges of the graphene structure in the carbon material raw material. Therefore, for solvated lithium ions to be embedded from the edges of the graphene structure, desolvation can be promoted while suppressing side reactions.

[0205] The atomic concentration x of aluminum atoms in the carbon material of this embodiment (Al) (atomic %) as long as the above is derived from x (Al) / y(atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 It is acceptable, without any particular limitation, but specifically, it is preferably 0.1 to 15 atoms.

[0206] The atomic concentration x of the above aluminum atoms (Al) (Atomic %) can be adjusted by increasing or decreasing the amount of aluminum-containing compound added when mixed with carbon material raw materials.

[0207] • Phosphorus atom

[0208] In this embodiment, phosphorus atoms, which are constituent elements of the carbon material and serve as modifying components, are introduced by reacting a phosphorus-containing compound with the carbon material raw material.

[0209] Phosphorus atoms exist on the surface of carbon materials through bonding with carbon atoms in the raw materials, and also at the edges of the graphene structure within the raw materials. When aluminum and phosphorus are included as modifying elements, the selective reaction of aluminum with phosphorus atoms allows for more appropriate suppression of side reactions and promotion of desolvation of solvated lithium ions that are to be inserted from the edges of the graphene structure.

[0210] When aluminum and phosphorus are included as constituent elements for modification, as described above, the atomic concentration of phosphorus atoms in the carbon material of this embodiment is preferably adjusted to 0.1 to 1 when the atomic concentration of aluminum atoms in the carbon material is set to 1. Specifically, although it varies depending on the atomic concentration of aluminum atoms, it is preferably 0.01 to 15 atoms, for example.

[0211] The atomic concentration (atomic %) of phosphorus atoms can be adjusted by increasing or decreasing the amount of phosphorus-containing compounds added when mixed with carbon material raw materials.

[0212] Boron, sulfur, germanium

[0213] In this embodiment, boron atoms, which are constituent elements of the carbon material and serve as modifying components, are introduced by reacting a boron-containing compound with the carbon material raw material.

[0214] In this embodiment, sulfur atoms, which are constituent elements of the carbon material and serve as modifying components, are introduced by reacting a sulfur-containing compound with the carbon material raw material.

[0215] In this embodiment, germanium atoms, which are constituent elements of the carbon material and serve as modifying components, are introduced by reacting a germanium-containing compound with the carbon material raw material.

[0216] In this embodiment, the molecular weight of the modifying component is preferably 500 or less, more preferably 100 to 500, and even more preferably 100 to 400. From the viewpoint of ease of modification, the molecular weight is preferably 500 or less, more preferably 400 or less, and even more preferably 300 or less.

[0217] More preferably, the modifying component in this embodiment comprises silicon or aluminum, and the molecular weight of the modifying component is 500 or less. Furthermore, more preferably, the modifying component in this embodiment comprises silicon or aluminum, and the total content of the modifying component in the carbon material is 1% by volume or less. Moreover, it is even more preferably that the modifying component comprises silicon or aluminum, the total content of the modifying component in the carbon material is 1% by volume or less, and the molecular weight of the modifying component is 500 or less.

[0218] • Connector

[0219] In the above general formula (1), the linker represented by L is a single bond or a (n+1) valent hydrocarbon group with 1 to 6 carbon atoms. n is 1 or 2, and from the viewpoint of controlling reactivity, n is preferably 1. Examples of hydrocarbon groups include aliphatic hydrocarbon groups such as alkylene and alkenylene, and aromatic hydrocarbon groups such as phenylene. From the viewpoint of maturing the reaction of the modified component, a single bond or a (n+1) valent aliphatic hydrocarbon group with 1 to 6 carbon atoms is preferred, a single bond or a (n+1) valent alkylene group with 1 to 6 carbon atoms is more preferred, and a single bond or a divalent alkylene group with 1 to 6 carbon atoms is even more preferred.

[0220] <Other Ingredients>

[0221] In addition to containing carbon material raw materials and silicon, aluminum, phosphorus, boron, sulfur atoms and germanium as constituent elements that serve as modifying components, the carbon material in this embodiment may also contain other components within a range that does not impair the effects of the present invention.

[0222] Other components include, for example, metal particles, metal oxide particles, organic compounds, and their complexes.

[0223] Metals that constitute metal particles and metal oxide particles include Sn, Bi, and other metals that can be alloyed with lithium.

[0224] From the viewpoint of forming a robust film, compounds having multiple hydroxyl groups or groups capable of self-crosslinking through heat or light are preferred as organic compounds. Examples include polyol resins such as polyvinyl alcohol resins, acrylic polyol resins, polyester polyol resins, and polyether polyol resins, as well as silicone resins, epoxy resins, acrylic resins with hydrolyzable silane groups, and polyester resins.

[0225] Among these, polyvinyl alcohol resins, acrylic polyol resins, polyester polyol resins, acrylic resins with hydrolyzable silane groups, and polyester resins are more preferred. Polyvinyl alcohol resins, acrylic polyol resins, and polyester polyol resins are even more preferred. From the viewpoint of solvent resistance as a negative electrode active material layer, polyvinyl alcohol resins are particularly preferred.

[0226] Polyvinyl alcohol (PVA) based resins can be any resin containing vinyl alcohol structural units; their specific structure is not particularly limited. Typically, they are obtained by saponifying polyvinyl carboxylate monomers such as vinyl acetate, which are polymerized from carboxylic acid ester monomers, but this is not a limitation.

[0227] The total content of other components in the carbon material of this embodiment is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 1.5 to 7% by mass. Here, when other components are present, from the viewpoint of obtaining their effects, the above-mentioned total content is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more. Furthermore, from the viewpoint of ensuring battery capacity, the above-mentioned total content is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 7% by mass or less.

[0228] Methods for manufacturing carbon materials

[0229] The carbon material in this embodiment includes: x (atomic %) representing the total atomic concentration of the constituent elements of the modifying components, and y (m²) representing the specific surface area of ​​the carbon material. 2 / g) when x / y (atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 This is a process of mixing carbon material raw materials with compounds used as modifying ingredients.

[0230] Furthermore, preferably, it also includes a step of heating the mixture obtained in the above-described mixing process.

[0231] For example, in the case where silicon atoms are included as a modifying element, the carbon material of this embodiment includes: a silicon atom concentration set to x. (Si) (atomic %), the specific surface area of ​​carbon materials is set as y(m 2 / g) when x (Si) / y(atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 This is a process of mixing carbon material raw materials with compounds used as modifying ingredients.

[0232] Furthermore, preferably, it also includes a step of heating the mixture obtained in the above-described mixing process.

[0233] atomic concentration x of silicon atoms in carbon materials (Si) (atomic %) is preferably 0.1 to 15 atoms, more preferably 0.2 to 10 atoms, and even more preferably 0.3 to 5 atoms.

[0234] In addition, the specific surface area y(m) of carbon materials 2 / g) is preferably 1-15m 2 / g, more preferably 1.2 to 10m 2 / g, more preferably 1.4–5m 2 / g.

[0235] In the case where aluminum atoms are included as a modifying element, the carbon material of this embodiment includes: a carbon material with an aluminum atom concentration set to x. (Al) (atomic %), the specific surface area of ​​carbon materials is set as y(m 2 / g) when x (Al) / y(atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 This is a process of mixing carbon material raw materials with aluminum-containing compounds.

[0236] Furthermore, preferably, it also includes a step of heating the mixture obtained in the above-described mixing process.

[0237] In the above mixing process, it is preferable to further mix a phosphorus-containing compound, more preferably to further mix an aluminum-containing compound after mixing the carbon material raw material and the phosphorus-containing compound, and even more preferably to further mix the carbon material raw material with the aluminum-containing compound after mixing the carbon material raw material and the phosphorus-containing compound to obtain a phosphate-containing carbon material raw material.

[0238] atomic concentration x of aluminum atoms in carbon materials (Al) (atomic %) is preferably 0.1 to 15 atoms, more preferably 0.2 to 10 atoms, and even more preferably 0.3 to 5 atoms.

[0239] In addition, the specific surface area y(m) of carbon materials 2 / g) is preferably 1-15m 2 / g, more preferably 1.2 to 10m 2 / g, more preferably 1.4–5m 2 / g.

[0240] In the above mixing process, when further mixing with phosphorus-containing compounds, the proportion of phosphorus atoms in the resulting carbon material is preferably 0.1 to 1, more preferably 0.15 to 0.95, and even more preferably 0.2 to 0.9, based on the atomic concentration ratio when the atomic concentration of aluminum atoms is set to 1.

[0241] Next, each process will be explained.

[0242] <Mixed Process>

[0243] In the process of mixing carbon material raw materials with compounds that serve as modifying components, such as silicon-containing compounds and aluminum-containing compounds, the carbon material raw materials can be the same as those described in the "Carbon Material Raw Materials" section of the aforementioned "Carbon Materials" book, and the preferred embodiment is also the same.

[0244] For example, the carbon material raw material preferably includes at least one selected from the group consisting of artificial graphite and natural graphite. Furthermore, the Raman R value of the carbon material raw material is preferably 0.01 to 0.7, more preferably 0.02 to 0.65, and even more preferably 0.03 to 0.6.

[0245] In addition, carbon material raw materials can also be obtained by further spheroidizing the above-mentioned carbon material raw materials.

[0246] Spheroidization refers to a process that uses impact force as the primary component, repeatedly applying mechanical actions such as compression, friction, and shear forces, including particle interactions, to particles to achieve spheroidization. In spheroidization devices, for example, a rotor with multiple blades is located inside the casing. This rotor rotates at high speed, applying mechanical actions such as impact, compression, friction, and shear forces to the carbon material raw material introduced into the casing, thereby achieving surface treatment.

[0247] Before mixing the carbon material raw material with the compound used as a modifying component, the carbon material raw material can also be subjected to isotropic pressure treatment.

[0248] By isotropically pressurizing the carbon material raw material, the internal voids of the carbon material are compressed. As a result, the density of the crushed carbon material raw material increases after pressurization, which improves its high-speed charging characteristics.

[0249] Furthermore, by isotropically pressurizing the carbon material raw material, particle flattening is less likely to occur, thus maintaining a spherical shape and preventing a decrease in fluidity during slurry preparation.

[0250] The pressurizing unit can be a roller compactor, roller press, briquetting machine, cold isostatic pressing (CIP) device, uniaxial forming machine, tablet press, etc. Among these pressurizing units, from the viewpoint of reducing internal pores while maintaining particle shape, a cold isostatic pressing device is preferred.

[0251] Here, when the compound used as a modifying component is a silicon-containing compound, the silicon-containing compound is any compound in which silicon atoms are bonded to the surface of the carbon material raw material, and there are no particular limitations. Examples include silane coupling agents such as alkoxysilanes, and silane compounds having amino, epoxy, isocyanate, vinyl, or acetyl groups. Among these, from the viewpoint of being able to suppress the reactivity of unsaturated bonds with high electron density and free radicals, silane compounds having vinyl or acetyl groups are preferred.

[0252] From the viewpoint that the removal of substituents after the reaction is easy and the battery resistance is suppressed, it is more preferable for the number of carbon-silicon bonds to be two or less as an alkoxysilane.

[0253] Specifically, examples include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, acetyltrimethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, methylethyldimethoxysilane, methylphenyldimethoxysilane, and methylvinyldimethoxysilane.

[0254] Silane compounds containing an amino group are not particularly limited as long as they contain an amino group. However, to suppress battery resistance, it is preferable that the number of carbon-silicon bonds is two or less.

[0255] Specifically, examples include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, phenylaminopropyltrimethoxysilane, 3-aminoethylaminopropyltrimethoxysilane, and 3-aminoethylaminopropylmethyldimethoxysilane.

[0256] Silane compounds with epoxy groups are not particularly limited as long as they have epoxy groups. However, to suppress battery resistance, it is preferable that the number of carbon-silicon bonds is two or less.

[0257] Specifically, examples include 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0258] Silane compounds with isocyanate groups are not particularly limited as long as they have isocyanate groups. However, to suppress battery resistance, it is preferable that the number of carbon-silicon bonds is two or less.

[0259] Specifically, examples include tetraisocyanosilane, triisocyanate-methyl silane, and 3-isocyanate-propyltriethoxysilane.

[0260] Silane compounds containing vinyl and acetyl groups are not particularly limited as long as they contain vinyl and acetyl groups. However, to suppress battery resistance, it is preferable that the number of carbon-silicon bonds is two or less.

[0261] Specifically, examples include dimethoxymethylvinylsilane, diethoxymethylvinylsilane, dichloromethylvinylsilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, aryltrimethoxysilane, aryltriethoxysilane, trichlorovinylsilane, vinyltri(2-methoxyethoxy)silane, acetyltrimethoxysilane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, 5-(triethoxysilyl)-2-norbornene, and octavinyloctasilsesquioxane, etc.

[0262] The mixing ratio of carbon material raw materials to silicon-containing compounds is set as x, where the atomic concentration of silicon atoms in the resulting carbon material is denoted as x. (Si) (atomic %), the specific surface area of ​​carbon materials is set as y(m 2 / g) when x (Si) / y(atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 The method is adjusted accordingly. Here, the specific surface area y(m²) of the carbon material is... 2 / g) and the specific surface area (m²) of carbon material raw materials 2 / g) are strictly different, but when the above mixing ratio is determined, they can be regarded as the same value to determine the mixing ratio.

[0263] When the compound used as a modifying component is an aluminum-containing compound, any compound with aluminum atoms bonded to the surface of the carbon material raw material is acceptable, without particular limitation. Examples include aluminum compounds that react with acids; more specifically, examples include aluminum alkoxy compounds, aluminum halides, aluminum hydroxide, aluminum nitrate, and aluminum carbonate. Among these, considering the impact of impurities on battery performance, aluminum alkoxy compounds and aluminum hydroxide are preferred.

[0264] As an alkoxyaluminum, an alkoxyaluminum that is easier to remove the substituents after the reaction is preferred.

[0265] Specifically, examples include (ethyl acetoacetate) diisopropoxyaluminum, trimethoxyaluminum, triethoxyaluminum, tri(isopropoxy)aluminum, and butoxyaluminum.

[0266] As an aluminum halide, an aluminum halide that allows for easy removal of substituents after the reaction is preferred.

[0267] Specifically, examples include aluminum fluoride, aluminum chloride, aluminum bromide, and aluminum iodide.

[0268] The mixing ratio of carbon material raw materials to aluminum-containing compounds is set as x, where the atomic concentration of aluminum atoms in the resulting carbon material is denoted as x. (Al) (atomic %), the specific surface area of ​​carbon materials is set as y(m 2 / g) when x (Al) / y(atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 The method is adjusted accordingly. Here, the specific surface area y(m²) of the carbon material is... 2 / g) and the specific surface area (m²) of carbon material raw materials 2 / g) are strictly different, but when the above mixing ratio is determined, they can be regarded as the same value to determine the mixing ratio.

[0269] Whether the compound used as a modifying ingredient is liquid or solid, a solvent can be used when mixing it with carbon material raw materials. In particular, when the compound used as a modifying ingredient is solid, a solvent is preferred from the viewpoint of uniformity during mixing.

[0270] The solvent is not particularly limited, and examples include water, methyl ethyl ketone, toluene, acetone, methyl isobutyl ketone, ethanol, methanol, tetrahydrofuran, and ethylene glycol dimethyl ether. Among these, ethanol, methanol, and acetone are preferred from the viewpoint of ease of removal.

[0271] When mixing carbon material raw materials and compounds as modifying ingredients, additives and other components may also be added.

[0272] Examples of additives include surfactants that help impart wettability and adhesion to negative electrode active materials and adhesive resins; inorganic oxide particles that help reduce the resistance of the coating; lithium compound particles; conductive polymers such as polyaniline sulfonic acid; and compounds such as polyethylene oxide and complexed hydrides that form complexes with lithium ions.

[0273] In addition, other components may be listed as those identical to those described in the "Other Components" section of the aforementioned "Carbon Materials".

[0274] In the mixing process of this embodiment, when the compound used as the modifying component is an aluminum-containing compound, as described above, it is preferable to further mix the phosphorus-containing compound with the carbon material raw material as well. More preferably, after mixing the carbon material raw material and the phosphorus-containing compound, the aluminum-containing compound is further mixed. Even more preferably, after mixing the carbon material raw material and the phosphorus-containing compound to obtain a phosphate-containing carbon material raw material, it is further mixed with the aluminum-containing compound.

[0275] Phosphorus-containing compounds are any compounds with phosphate groups bonded to the surface of carbon material raw materials, without particular limitations. Examples include vinylphosphonic acid compounds and ethynylphosphonic acid compounds. Among these, aminophosphonic acid compounds, vinylphosphonic acid compounds, and ethynylphosphonic acid compounds are preferred from the viewpoint that they can form strong bonds with the edges of the graphene structure of carbon materials.

[0276] As for phosphonic acid, any phosphonic acid that can form a bond with the edge of the graphene structure of carbon materials is acceptable, and there is no particular limitation. However, from the perspective of being able to react with the unsaturated bonds at the edge, phosphonic acid that has unsaturated carbon bonds in a part of the phosphonic acid is more preferred.

[0277] Specifically, examples include vinylphosphonic acid, dimethyl vinylphosphonic acid, diethyl vinylphosphonic acid, dipropyl vinylphosphonic acid, dibutyl vinylphosphonic acid, dimethyl allylphosphonic acid, diethyl allylphosphonic acid, dipropyl allylphosphonic acid, dibutyl allylphosphonic acid, cinnamylphosphonic acid, ethynylphosphonic acid, dimethyl ethynylphosphonic acid, diethyl ethynylphosphonic acid, dipropyl ethynylphosphonic acid, dibutyl ethynylphosphonic acid, dimethyl ethynylphosphonic acid, diethyl ethynylphosphonic acid, dipropyl ethynylphosphonic acid, dibutyl ethynylphosphonic acid, diethyl ethynylphosphonic acid, dipropyl ethynylphosphonic acid, dibutyl ethynylphosphonic acid, etc.

[0278] As an amide phosphate compound, any compound that can form a bond with the edge of the graphene structure of a carbon material is acceptable, and there are no particular limitations. However, considering the ability to react efficiently with the acid functional groups at the edge of the graphene structure of a carbon material, amide phosphate esters are more preferred.

[0279] Specifically, dimethylphosphoramide, diethylphosphoramide, dipropylphosphoramide, and dibutylphosphoramide can be listed.

[0280] The mixing ratio of carbon material raw material and phosphorus-containing compound is preferably adjusted such that the atomic concentration of phosphorus atoms in the obtained carbon material is 0.1 to 1 relative to the atomic concentration of aluminum atoms in the carbon material.

[0281] Whether the phosphorus-containing compound is liquid or solid, a solvent can be used when mixing it with carbon material raw materials. Especially when the phosphorus-containing compound is solid, a solvent is preferred from the viewpoint of uniformity during mixing.

[0282] The solvent is not particularly limited, and examples include water, methyl ethyl ketone, toluene, acetone, methyl isobutyl ketone, ethanol, methanol, tetrahydrofuran, and ethylene glycol dimethyl ether. Among these, ethanol, methanol, and acetone are preferred from the viewpoint of ease of removal.

[0283] When a phosphorus-containing compound is mixed with a carbon material raw material to obtain a phosphoric acid-containing carbon material raw material, it is preferable to heat the mixture after mixing the phosphorus-containing compound.

[0284] The heating temperature is not particularly limited, but is preferably 60 to 200°C, and more preferably 100 to 180°C.

[0285] There is no particular limitation on the heating time, but it is preferred to be 15 minutes to 10 hours, and more preferably 30 minutes to 2 hours.

[0286] From the perspective of suppressing oxidation reactions, the atmosphere during heating is preferably an inert atmosphere, such as a nitrogen atmosphere, an argon atmosphere, or a helium atmosphere.

[0287] Alternatively, after the above heating, the phosphate-containing carbon material raw material can be cooled, cleaned and dried as needed, and then mixed with an aluminum-containing compound. Cleaning removes excess phosphorus-containing compounds and other residues that are not bonded to the carbon material raw material, and inhibits reactions with the aluminum-containing compound, reducing battery capacity and increasing battery resistance.

[0288] Cleaning can be done using solutions that are known in the past, such as the same solvent used during mixing.

[0289] There are no particular limitations on the mixing method between the carbon material raw material and the compound used as a modifying ingredient; conventionally known methods can be used. Examples include methods such as stirring with a stirring blade in a fixed container, mixing by rotating the container itself to rotate the contents, and mixing by fluidizing the contents with an airflow. From the viewpoint of mixing uniformity, the method of stirring with a stirring blade in a fixed container is preferred.

[0290] In the method of mixing carbon material raw materials and aluminum-containing compounds and stirring with stirring blades in a fixed container, it is more preferable to stir a dispersion formed by dispersing carbon material raw materials in a solvent and then add a solution containing aluminum-containing compounds dropwise thereto.

[0291] The mixing time is not particularly limited as long as the carbon material raw material and the compound used as the modifying component are mixed evenly. It is preferably 10 to 90 minutes, more preferably 30 to 60 minutes. Here, the above-mentioned mixing time is preferably 10 minutes or more, more preferably 30 minutes or more, and further preferably 90 minutes or less, more preferably 60 minutes or less.

[0292] The mixing temperature is not particularly limited, but is preferably 10 to 80°C, more preferably 15 to 60°C. Here, the above-mentioned mixing temperature is preferably 10°C or higher, more preferably 15°C or higher, and further preferably 80°C or lower, more preferably 60°C or lower.

[0293] <Heating Process>

[0294] In the heating process, the mixture obtained in the above-mentioned mixing process is heated. When the modifying compound is a silicon-containing compound, heating causes the reactive substituents of the silicon-containing compound to react with the active functional groups located at the edges of the carbon material raw material, thereby enabling the silicon atoms contained in the silicon-containing compound to bond to the surface of the carbon material raw material. Furthermore, if a solvent is used in the mixing process, heating can also be used to remove the solvent.

[0295] Alternatively, the heating process can be performed after solid-liquid separation through filtration or other means, prior to the heating process.

[0296] When the modifying compound is an aluminum-containing compound, heating, in the presence of a liquid aluminum-containing or phosphorus-containing compound, causes the compound to volatilize or decompose. The aluminum atoms and phosphorus-based phosphate groups in the aluminum-containing or phosphorus-containing compounds react with active functional groups located at the edges of the carbon material raw material, thereby enabling the aluminum and phosphorus atoms to bond to the surface of the carbon material raw material. Furthermore, when a solvent is used in the mixing process, heating can also be used to remove the solvent.

[0297] Alternatively, the heating process can be performed after solid-liquid separation through filtration or other means, prior to the heating process.

[0298] The heating temperature is not particularly limited, but is preferably 60–300°C, more preferably 100–250°C, and even more preferably 100–180°C. Heating at 120°C or higher is also preferred. Here, the aforementioned heating temperature is preferably 60°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. Furthermore, it is preferably below 300°C, more preferably below 250°C, and can be below 200°C or below 180°C.

[0299] When the compound used as a modifying ingredient is a silicon-containing compound, the heating temperature is preferably 60–200°C, more preferably 100–180°C. Heating at 120°C or higher is also preferred. When the compound used as a modifying ingredient is an aluminum-containing compound, the heating temperature is preferably 60–300°C, more preferably 100–250°C. Heating at 120°C or higher is also preferred.

[0300] Alternatively, the mixing process can be carried out while heating, thus also serving as the formal heating process.

[0301] The heating time is not particularly limited, but is preferably 15 minutes to 10 hours, more preferably 30 minutes to 2 hours. Here, the heating time is preferably 15 minutes or more, more preferably 30 minutes or more, and preferably 10 hours or less, more preferably 2 hours or less.

[0302] Preferably, the heating temperature in the mixing process is 60–300°C, and the heating time is 15 minutes to 10 hours.

[0303] There are no particular restrictions on the atmosphere used for heating; it can be in air or in an inert atmosphere. Examples of inert atmospheres include nitrogen, argon, and helium.

[0304] In the case where the compound used as a modifying component is a silicon-containing compound, from the viewpoint of suppressing oxidation reactions, the atmosphere during heating is preferably an inactive atmosphere.

[0305] Alternatively, the carbon material can be cooled, cleaned again, and dried after the heating process. Cleaning removes excess residues such as compounds that are not bonded to the carbon material raw material, which can suppress the decrease in battery capacity and the increase in battery resistance.

[0306] Cleaning can be done using solutions that are already known, such as the same solvent used in the mixing process.

[0307] The heating temperature during drying is typically above the boiling point of the solvent and below its auto-ignition point, preferably 20–150°C, more preferably 40–100°C. Here, the heating temperature is preferably 20°C or higher, more preferably 40°C or higher, and further preferably 150°C or lower, more preferably 100°C or lower. By ensuring thorough drying, the reduction in battery performance caused by solvent or residue residue can be suppressed.

[0308] Drying can also be carried out under reduced pressure. The pressure under this condition, expressed as gauge pressure (the difference from atmospheric pressure), is typically -0.1 MPa or higher, preferably -0.08 MPa or higher, and is also typically 0 MPa or lower, preferably -0.03 MPa or lower.

[0309] The obtained carbon material can be processed into powders such as crushing, breaking, and grading as needed.

[0310] There are no particular restrictions on the devices used for crushing and grinding. For example, coarse crushers include shear mills, jaw crushers, impact crushers, and cone crushers.

[0311] Examples of intermediate crushers include roller crushers and hammer mills. Examples of micro-grinding mills include ball mills, vibratory mills, pin mills, stirred mills, and jet mills.

[0312] There are no particular limitations on the devices used for grading. In the case of dry screening, examples include rotary screens, oscillating screens, rotating screens, and vibrating screens.

[0313] In the case of dry airflow classification, examples include gravity classifiers, inertial classifiers, and centrifugal classifiers (particle separators, cyclone separators, etc.).

[0314] In addition, wet screening, mechanical wet classifiers, hydraulic classifiers, sedimentation classifiers, centrifugal wet classifiers, etc. can also be used.

[0315] Composition

[0316] To achieve the second objective described above, the composition of this embodiment preferably comprises compound (A) and a crosslinked siloxane compound (B), wherein compound (A) comprises a polyoxyalkylene structure and the crosslinked siloxane compound (B) comprises a Q unit. More preferably, compound (A) has at least two crosslinked silicon units in one molecule.

[0317] The composition of this embodiment comprises compound (A) and crosslinked siloxane compound (B), wherein compound (A) comprises a polyoxyalkylene structure that contributes to flexibility and crosslinked siloxane compound (B) comprises Q units that contribute to strength, thus the cured product obtained from the composition has excellent adhesion and durability.

[0318] The three-dimensional siloxane structure containing Q units in the cured product obtained from the composition can control the intrusion of water and organic solvents into the cured product, and inhibit the dissolution of components from the cured product and the swelling of the cured product. Furthermore, the crosslinked siloxane compound (B) containing Q units can be cured at low temperatures, thus allowing the cured product to be obtained at a temperature lower than the thermal decomposition temperature of the compound (A) containing the polyoxyalkylene structure, thereby suppressing the dissolution of components from the cured product due to thermal decomposition. Moreover, the polyoxyalkylene structure contributes to lithium-ion conductivity; therefore, by using the composition of this embodiment, a secondary battery with excellent durability can be obtained without compromising charge-discharge efficiency.

[0319] <Compound (A)>

[0320] The composition of this embodiment contains a compound (A) having a polyoxyalkylene structure (hereinafter, sometimes referred to as "compound (A)"). By including compound (A), the composition of this embodiment results in a cured product with excellent adhesion, flexibility, and lithium-ion conductivity.

[0321] Examples of compounds (A) include polyethylene glycol, polypropylene glycol, polybutane glycol, polypentylene glycol, polyhexane glycol, and copolymers thereof. These compounds (A) can be used alone or in combination of two or more.

[0322] Among these compounds (A), polyethylene glycol and polypropylene glycol are preferred, with polyethylene glycol being more preferred, considering their excellent solubility in various solvents. Compound (A) can be either a diol or a triol.

[0323] Compound (A) may also contain various functional groups other than hydroxyl groups within a range that does not impair the effects of the present invention. From the viewpoint of improving compatibility and reactivity with the crosslinked siloxane compound (B), and improving the durability of the cured product obtained from the composition, compound (A) preferably contains crosslinked silicon units. Specifically, compound (A) is preferably a compound having at least one crosslinked silicon unit in one molecule, and more preferably a compound having two crosslinked silicon units in one molecule.

[0324] From the perspective that compound (A) can react with crosslinked siloxane compound (B) containing Q unit and can suppress the decomposition of the cured product accompanied by dissolution, crosslinked silicon unit D unit and T unit are preferred. From the perspective that there are many crosslinking points and dissolution and swelling can be suppressed at the same time, crosslinked silicon unit T unit is more preferred.

[0325] It should be noted that, in this specification, a silicon unit bonded to one oxygen and three organic groups is referred to as an M unit, a silicon unit bonded to two oxygens and two organic groups is referred to as a D unit, a silicon unit bonded to three oxygens and one organic group is referred to as a T unit, and a silicon unit bonded to four oxygens is referred to as a Q unit.

[0326] In the case where the crosslinked siloxane compound (B) containing the Q unit contains a reactive organic group derived from a silane coupling agent, the compound (A) may also have a reactive organic group that reacts with the reactive organic group of the crosslinked siloxane compound (B) containing the Q unit.

[0327] Examples of reactive organic groups include vinyl, amino, epoxy, methacryloyl, carboxyl, isocyanate, and silyl groups.

[0328] The weight-average molecular weight (Mw) of compound (A) is preferably 500 to 50,000, more preferably 1,000 to 2,000. Here, considering excellent non-volatility and reasonable solubility in water and organic solvents, the aforementioned weight-average molecular weight is preferably 500 or more, more preferably 1,000 or more. Furthermore, considering its resistance to precipitation and crystallization in the composition, excellent stability of the composition, and excellent compatibility with the crosslinked siloxane compound (B) containing Q units, the aforementioned weight-average molecular weight is preferably 50,000 or less, more preferably 20,000 or less.

[0329] In this specification, the weight-average molecular weight Mw is the value determined by gel permeation chromatography.

[0330] <Compound (B)>

[0331] The composition of this embodiment contains a crosslinked siloxane compound (B) containing a Q unit (hereinafter, sometimes referred to as "compound (B)"). By containing compound (B), the composition of this embodiment can reduce the dissolution rate and swelling rate of the cured product obtained from the composition in water and organic solvents, and exhibits excellent durability.

[0332] Examples of raw materials for compound (B) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, partially hydrolyzed oligomers of the above tetraalkoxysilanes, and modified oligomers having two or more alkoxy groups. These raw materials for compound (B) can be used alone or in combination with two or more groups.

[0333] Among the raw materials for these compounds (B), from the perspective of excellent curability, partially hydrolyzed oligomers of tetraalkoxysilanes are preferred, and partially hydrolyzed oligomers of tetramethoxysilanes are more preferred.

[0334] Considering the excellent compatibility with compound (A) and the excellent storage stability of the composition, the partially hydrolyzed oligomer of tetraalkoxysilane is preferably a 2-200 polymer, more preferably a 2-100 polymer, and even more preferably a 2-10 polymer.

[0335] Compound (B) can be obtained by hydrolyzing the raw material of the above-mentioned compound (B).

[0336] For the purpose of improving compatibility with compound (A), the raw materials of compound (B) may also be used in conjunction with silane coupling agents, alkoxysilanes with non-reactive organic groups.

[0337] <Compound (C)>

[0338] The composition of this embodiment may also contain, in addition to compounds (A) and (B), a boron-containing compound (C) (hereinafter, sometimes referred to as "compound (C)"). The composition of this embodiment, by also containing compound (C), can reduce resistance and exhibits excellent suppression of intra-cell side reactions in the carbon material containing the cured form of the composition (sometimes referred to as "cured carbon material").

[0339] Compound (C) is highly soluble in water and organic solvents in its monomeric form, but by using it in combination with compounds (A) and (B), the boron-bonded hydroxyl groups react with the hydroxyl groups, silanol groups of compound (A), and silanol groups of compound (B), thereby inhibiting the dissolution from the cured product.

[0340] Examples of compounds (C) include boric acid, boron oxide, metaboric acid, tetraboric acid, borates, alkoxides with 1 to 3 carbon atoms bonded to boron, lithium borate, and organoboronic acids. These compounds (C) can be used alone or in combination of two or more. Among these compounds (C), boric acid, boron oxide, and organoboronic acids are preferred from the perspective of excellent stability; boric acid and phenylboronic acid are more preferred. Aromatic boric acids are more preferred as organoboronic acids.

[0341] <solvent>

[0342] The composition of this embodiment may also contain a solvent in addition to compounds (A) and (B). Furthermore, it may also contain compound (C) and a solvent in addition to compounds (A) and (B). Because it contains a solvent, the composition of this embodiment exhibits excellent workability as a coating.

[0343] Examples of solvents include water, methanol, ethanol, propanol, isopropanol, butanol, acetonitrile, acetone, and tetrahydrofuran. These solvents can be used individually or in combination of two or more.

[0344] Among these solvents, water, methanol, ethanol, and isopropanol are preferred, with methanol and ethanol being more preferred, considering the high productivity of obtaining cured products from the composition, the high solubility of compound (A) containing a polyoxyalkylene structure, and the excellent storage stability of the composition.

[0345] The composition of this embodiment may also contain other components in addition to compound (A), compound (B), compound (C) and solvent, without impairing the effects of the present invention.

[0346] <Composition of the composition>

[0347] The content of compound (A) in the composition of this embodiment is preferably 10 to 90% by mass, more preferably 20 to 80% by mass. From the viewpoint of excellent flexibility and lithium-ion conductivity of the cured product obtained from the composition, the above-mentioned content is preferably 10% by mass or more, more preferably 20% by mass or more. Furthermore, from the viewpoint of excellent durability of the cured product obtained from the composition, the above-mentioned content is preferably 90% by mass or less, more preferably 80% by mass or less.

[0348] The content of compound (A) in the composition is the content of compound (A), compound (B), compound (C) and other components in a total of 100% by mass.

[0349] The content of compound (B) in the composition of this embodiment is preferably 10 to 90% by mass, more preferably 20 to 80% by mass. From the viewpoint of excellent durability of the cured product obtained from the composition, the above-mentioned content is preferably 10% by mass or more, more preferably 20% by mass or more. Furthermore, from the viewpoint of excellent flexibility of the cured product obtained from the composition, the above-mentioned content is preferably 90% by mass or less, more preferably 80% by mass or less.

[0350] The content of compound (B) in the composition is the content of compound (A), compound (B), compound (C) and other components in a total of 100% by mass.

[0351] The mass ratio of compound (B) to compound (A) (mass of compound (B) / mass of compound (A)) is preferably 0.2 to 5, more preferably 0.3 to 3. From the viewpoint of excellent durability of the cured product obtained from the composition, the above-mentioned mass ratio is preferably 0.2 or more, more preferably 0.3 or more. Furthermore, from the viewpoint of excellent flexibility of the cured product obtained from the composition, the above-mentioned mass ratio is preferably 5 or less, more preferably 3 or less.

[0352] When using compound (C), the content of compound (C) in the composition of this embodiment is preferably 0.1 to 30% by mass, more preferably 0.3 to 20% by mass. From the perspective of excellent suppression of in-cell side reactions in the battery of the carbon material containing the cured product obtained from the composition, the above-mentioned content is preferably 0.1% by mass or more, more preferably 0.3% by mass or more. Furthermore, from the perspective of excellent durability of the cured product obtained from the composition, the above-mentioned content is preferably 30% by mass or less, more preferably 20% by mass or less. In addition, the content of compound (C) is preferably less than the content of at least one of compound (A) and compound (B), more preferably less than the content of both compound (A) and compound (B).

[0353] The content of compound (C) in the composition is the content of compound (A), compound (B), compound (C) and other components in a total of 100% by mass.

[0354] The total content of other components in the composition of this embodiment is preferably 20% by mass or less, more preferably 10% by mass or less, or may be 0% by mass, i.e., not included.

[0355] The total content of other components in the composition is the content of compound (A), compound (B), compound (C) and other components in a total of 100% by mass.

[0356] When using a solvent, the solvent content relative to 100 parts by weight of the composition of this embodiment is preferably 5 to 99.9 parts by weight, more preferably 10 to 99.5 parts by weight. From the viewpoint of obtaining a uniform cured product from the composition, the above-mentioned content is preferably 5 parts by weight or more, more preferably 10 parts by weight or more. Furthermore, from the viewpoint of excellent productivity when obtaining a cured product from the composition, the above-mentioned content is preferably 99.9 parts by weight or less, more preferably 99.5 parts by weight or less.

[0357] The solvent content is relative to the total of 100 parts by mass of compound (A), compound (B), compound (C), and other components.

[0358] The polyoxyalkylene structure in the composition of this embodiment is preferably 10 to 60% by mass, more preferably 15 to 50% by mass. From the perspective of excellent flexibility and lithium-ion conductivity of the cured product obtained from the composition, the above-mentioned content is preferably 10% by mass or more, more preferably 15% by mass or more. Furthermore, from the perspective of excellent durability of the cured product obtained from the composition, the above-mentioned content is preferably 60% by mass or less, more preferably 50% by mass or less. It should be noted that the above-mentioned polyoxyalkylene structure refers to the polyoxyalkylene structure constituting compound (A) containing the polyoxyalkylene structure.

[0359] The content of polyoxyalkylene structures in the composition is the content of compounds (A), (B), (C) and other components totaling 100% by mass.

[0360] From the perspective of excellent durability of the cured product obtained from the composition, the total content of Q units in the composition of this embodiment is preferably 10% by mass or more, more preferably 15% by mass or more. From the perspective of excellent flexibility of the cured product obtained from the composition and non-impedement of lithium-ion conductivity, the total content of Q units in the composition of this embodiment is preferably 50% by mass or less, more preferably 40% by mass or less. It should be noted that the above-mentioned Q units refer to the Q units constituting the crosslinked siloxane compound (B) containing Q units.

[0361] The total content of Q units in the composition is the content of compounds (A), (B), and (C) in a total of 100% by mass.

[0362] <Thermosetting Compositions>

[0363] The composition of this embodiment is not particularly limited as long as it can be cured. However, considering the excellent productivity of the cured product obtained from the composition and the ability to suppress dissolution and swelling, a thermosetting composition is preferred.

[0364] The heating temperature for curing the thermosetting composition is preferably 80 to 200°C, more preferably 100 to 180°C. From the viewpoint of excellent productivity of the cured product obtained from the composition, the above-mentioned heating temperature is preferably 80°C or higher, more preferably 100°C or higher. Furthermore, from the viewpoint of preventing deterioration of the cured product obtained from the composition, the above-mentioned heating temperature is preferably 200°C or lower, more preferably 180°C or lower.

[0365] "Solid Object"

[0366] The cured product of this embodiment preferably contains a polyoxyalkylene structure and a three-dimensional siloxane structure containing Q units, and more preferably has a swelling rate of 70% by mass or less in ethyl methyl carbonate.

[0367] The cured product of this embodiment comprises a soft polyoxyalkylene structure and a three-dimensional siloxane structure containing high-strength Q units, thus exhibiting excellent flexibility and durability. The three-dimensional siloxane structure containing Q units in the cured product can control the intrusion of water and organic solvents into the cured product, inhibiting the dissolution of components from the cured product and the swelling of the cured product.

[0368] Specifically, the cured product of this embodiment is obtained by curing the composition described in the above-mentioned "Composition" document, and the preferred embodiment is the same. That is, preferably, the method for manufacturing the cured product of this embodiment includes a step of curing the composition described in the above-mentioned "Composition" document, wherein the curing step is a heating step.

[0369] There are no particular limitations on the method for curing the above composition to obtain a cured product, but from the perspective of high productivity, curing by heating is preferred.

[0370] The heating temperature is preferably 80–200°C, more preferably 100–180°C. From the perspective of excellent productivity, the heating temperature is preferably 80°C or higher, more preferably 100°C or higher. Furthermore, from the perspective of preventing deterioration during the production process, the heating temperature is preferably 200°C or lower, more preferably 180°C or lower.

[0371] From the perspective of suppressing the decomposition of polyoxyalkylene structures, the heating atmosphere is preferably an inactive gas atmosphere.

[0372] The content of the solid component derived from compound (A) in the cured product of this embodiment is preferably 10 to 90% by mass, more preferably 20 to 80% by mass. From the perspective of excellent flexibility of the cured product, the above-mentioned content is preferably 10% by mass or more, more preferably 20% by mass or more. Furthermore, from the perspective of excellent durability of the cured product, the above-mentioned content is preferably 90% by mass or less, more preferably 80% by mass or less.

[0373] The content of solid components derived from compound (A) in the cured product is the content in 100% by mass of the cured product.

[0374] The content of solid components derived from compound (B) in the cured product is preferably 10 to 90% by mass, more preferably 20 to 80% by mass. From the perspective of excellent durability of the cured product, the above-mentioned content is preferably 10% by mass or more, more preferably 20% by mass or more. Furthermore, from the perspective of excellent flexibility of the cured product, the above-mentioned content is preferably 90% by mass or less, more preferably 80% by mass or less.

[0375] The content of solid components derived from compound (B) in the cured product is the content in 100% by mass of the cured product.

[0376] The mass ratio of the solid component derived from compound (B) in the cured product to the solid component derived from compound (A) in the cured product (mass of compound (B) / mass of compound (A)) is preferably 0.2 to 5, more preferably 0.3 to 3. From the perspective of excellent durability of the cured product, the above-mentioned mass ratio is preferably 0.2 or more, more preferably 0.3 or more. Furthermore, from the perspective of excellent flexibility of the cured product, the above-mentioned mass ratio is preferably 5 or less, more preferably 3 or less.

[0377] When using compound (C), the content of solid components derived from compound (C) in the cured product of this embodiment is preferably 0.1 to 30% by mass, more preferably 0.3 to 20% by mass. From the perspective of excellent suppression of side reactions within the battery of the carbon material containing the cured product, the above-mentioned content is preferably 0.1% by mass or more, more preferably 0.3% by mass or more. Furthermore, from the perspective of excellent durability of the cured product, the above-mentioned content is preferably 30% by mass or less, more preferably 20% by mass or less.

[0378] The percentage of solid components derived from compound (C) in the cured product is the percentage of solid components in 100% by mass of the cured product.

[0379] In this embodiment, the total content of solid components derived from other components in the cured product is preferably 20% by mass or less, more preferably 10% by mass or less, or may be 0% by mass, i.e., not contained.

[0380] The total content of solid components derived from other components in the cured product is the content in 100% by mass of the cured product.

[0381] The content of polyoxyalkylene structures in the cured product of this embodiment is preferably 20 to 80% by mass, more preferably 30 to 70% by mass. From the perspective of excellent flexibility and lithium-ion conductivity of the cured product, the above-mentioned content is preferably 20% by mass or more, more preferably 30% by mass or more. Furthermore, from the perspective of excellent durability of the cured product, the above-mentioned content is preferably 80% by mass or less, more preferably 70% by mass or less.

[0382] The content of polyoxyalkylene structures in the cured product is the content in 100% by mass of the cured product.

[0383] The silicon atom content in the cured product of this embodiment is preferably 10 to 40% by mass, more preferably 15 to 30% by mass. From the perspective of excellent durability of the cured product, the above-mentioned content is preferably 10% by mass or more, more preferably 15% by mass or more. Furthermore, from the perspective of excellent flexibility of the cured product and not hindering lithium-ion conductivity, the above-mentioned content is preferably 40% by mass or less, more preferably 30% by mass or less.

[0384] The silicon content in the cured product is the content per 100% by mass of the cured product.

[0385] The total content of Q units in the cured product of this embodiment is preferably 20 to 60% by mass, more preferably 30 to 50% by mass. From the perspective of excellent durability of the cured product, the above-mentioned total content is preferably 20% by mass or more, more preferably 30% by mass or more. Furthermore, from the perspective of excellent flexibility of the cured product, the above-mentioned total content is preferably 60% by mass or less, more preferably 50% by mass or less.

[0386] The total content of Q units in the cured product is the content in 100% by mass of the cured product.

[0387] The swelling rate of the cured product in ethyl methyl carbonate in this embodiment is preferably less than 70% by mass, more preferably less than 60% by mass, even more preferably less than 50% by mass, and the lower the better, for example, more than 1% by mass.

[0388] The swelling rate mentioned above refers to the swelling rate after the cured material has been immersed in ethyl methyl carbonate at 23°C for 1 hour. This swelling rate can be calculated as the relative change in mass caused by 1 hour of immersion compared to the mass before immersion.

[0389] The cured product of this embodiment is preferably hydrolyzable, and more preferably, after hydrolysis, it produces a polyoxyalkylene structure and segments having at least two silicon atoms per molecule. From the viewpoint of controlling the three-dimensional structure of the polymer, the proportion of the polyoxyalkylene structure and segments having at least two silicon atoms per molecule relative to 100 mol% of segments having Si atoms is preferably 10 mol% or more, more preferably 30 mol% or more, further preferably 50 mol% or more, more preferably 50 to 100 mol%, and even more preferably 50 to 70 mol%.

[0390] The above ratio refers to the ratio under conditions that allow hydrolysis of the Si-O bonds in the cured material without hydrolyzing the polyoxyalkylene structure. This ratio can be determined using NMR.

[0391] Carbon materials containing solidified substances

[0392] The carbon material containing the cured product in this embodiment includes a cured product and a carbon material. Here, the cured product described in the above-mentioned "Curved Product" can be used, and the preferred embodiment is also the same. The carbon material will be described later.

[0393] In this embodiment, the carbon material containing cured material exhibits low dissolution and swelling rates in water and organic solvents, thus providing excellent suppression of side reactions within the battery. Therefore, the carbon material containing cured material in this embodiment can be appropriately used as a negative electrode active material.

[0394] In particular, the carbon material containing the cured product of the present invention has the following characteristics: it contains a polyoxyalkylene structure with lithium-ion conductivity, and the cured product has low electrical resistance. The three-dimensional siloxane structure without Q-units cannot suppress the swelling of the cured product. In the long term, the components containing the polyoxyalkylene structure dissolve from the cured product, and the cured product becomes a sparse structure, thus failing to maintain its protective properties as a carbon material.

[0395] On the other hand, the carbon material containing the cured product in this embodiment contains a three-dimensional siloxane structure with Q units, so the compatibility and uniformity of the cured product are controlled, swelling and dissolution are suppressed, and the structure of the cured product is maintained, thus enabling long-term suppression of side reactions in the battery.

[0396] The carbon material containing the cured material in this embodiment is obtained by curing the composition described in the above "Composition" in the presence of the carbon material.

[0397] The method for curing the above composition is not particularly limited, but heating is preferred from the perspective of excellent productivity. That is, one aspect of the method for manufacturing a carbon material containing a cured product according to this embodiment includes a step of heating the composition described in the above "Composition" in the presence of a carbon material. The resulting carbon material containing a cured product is preferably used as a negative electrode active material.

[0398] The heating temperature in the above-described heating process is preferably 80–200°C, more preferably 100–180°C. From the perspective of excellent productivity, the heating temperature is preferably 80°C or higher, more preferably 100°C or higher. Furthermore, from the perspective of preventing the deterioration of the cured product, the heating temperature is preferably 200°C or lower, more preferably 180°C or lower.

[0399] From the perspective of suppressing the decomposition of polyoxyalkylene structures, the heating atmosphere in the above-mentioned heating process is preferably an inert gas atmosphere.

[0400] <Carbon Materials>

[0401] The carbon material constituting the carbon material containing the cured product in this embodiment is not particularly limited. For example, the material described in the above-mentioned "Carbon Materials" can be used, and the preferred embodiment is also the same. That is, one embodiment of the carbon material preferably has a modifying component bonded to the carbon material raw material, and the modifying component includes at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur, and germanium.

[0402] Considering that graphite with higher crystallinity exhibits better compressibility and greater charge / discharge capacity during pressing, the preferred d002 value for the carbon material in this embodiment is... The following is preferred. the following.

[0403] Considering that the higher the crystallinity of graphite, the better its compressibility and the greater its charge / discharge capacity when pressed, the preferred Lc value for the carbon material in this embodiment is... The above is preferred. above.

[0404] In this specification, d002 is defined as the interplanar spacing of the lattice planes (002 planes) determined by X-ray diffraction using the vibratory method, and Lc is defined as the crystallite size determined by X-ray diffraction using the vibratory method. The X-ray diffraction measurement conditions are as follows.

[0405] Sample: Approximately 15% by mass of high-purity X-ray standard silicon powder was added to the test subject and mixed together.

[0406] X-rays: CuKα rays.

[0407] Measurement range: 20°≤2θ≤30°.

[0408] Step angle: 0.013°.

[0409] Sample adjustment: Fill the recessed part of the sample plate with powder sample to a depth of 0.2 mm to make a flat sample surface.

[0410] In this embodiment, the volume-based average particle size (d50) of the carbon material is preferably 1 to 50 μm, more preferably 10 to 30 μm. Here, considering the prevention of irreversible capacity increase and initial battery capacity loss, the aforementioned volume-based average particle size (d50) is preferably 1 μm or more, more preferably 4 μm or more, and even more preferably 10 μm or more. Furthermore, considering the ability to suppress process defects such as stripe formation during electrode fabrication and to achieve excellent fast charge / discharge characteristics and low-temperature input / output characteristics, the volume-based average particle size (d50) is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 25 μm or less.

[0411] In this specification, the volume reference average particle size (d50) is set as the value of the median particle size of the volume reference as measured by a laser diffraction / scattering particle size distribution measuring device.

[0412] Specifically, 0.01 g of the sample was suspended in 10 mL of a 0.2% by mass aqueous solution of polyoxyethylene sorbitan monolaurate as a surfactant, introduced into a laser diffraction / scattering particle size distribution measuring device, and irradiated with 28 kHz ultrasound for 1 minute at an output power of 60 W. The median particle size of the volume reference in the measuring device was then measured.

[0413] In this embodiment, the specific surface area (SA) of the carbon material is preferably 3.0 to 11.0 m². 2 / g, more preferably 4.0–9.0m 2 / g, more preferably 5.0–8.0m 2 / g. Here, considering the need to ensure lithium-ion exchange, excellent fast charge / discharge characteristics, and low-temperature input / output characteristics, the preferred specific surface area is 3.0 m². 2 / g or more, preferably 4.0m 2 / g or more, further preferably 5.0m 2 / g or more. Furthermore, considering the suppression of side reactions with the electrolyte, prevention of decreased initial charge / discharge efficiency, increase in gas generation, and improvement of battery capacity, the specific surface area is preferably 11.0 m². 2 / g or less, preferably 9.0m 2 / g or less, more preferably 8.0m 2 / g or less.

[0414] In this specification, the specific surface area (SA) is set as the value determined by the BET method.

[0415] Specifically, using a specific surface area measuring device, the sample is pre-depressurized and dried at 350°C for 15 minutes under nitrogen flow, then cooled to liquid nitrogen temperature. A nitrogen-helium mixed gas, precisely adjusted to a relative pressure of 0.3 nitrogen relative to atmospheric pressure, is used to determine the nitrogen adsorption BET single-point method using gas flow.

[0416] In this embodiment, the tap density of the carbon material is preferably 0.70–1.30 g / cm³. 3 More preferably, it is 0.80–1.20 g / cm³. 3 More preferably, it is 0.90–1.10 g / cm³. 3 Here, considering the ability to suppress process defects such as stripe formation during electrode fabrication, the ease of forming a high-density negative electrode sheet with good calendering properties due to improved filling, the reduced tortuosity of the lithium ion migration path during electrode body fabrication, the smoother electrolyte movement due to the regular shape of the interparticle gaps, and the improved fast charge / discharge characteristics, the aforementioned tap density is preferably 0.70 g / cm³. 3 The above, more preferably 0.80 g / cm 3 The above is further preferred to be 0.90 g / cm³. 3 The above. Furthermore, considering that the particles do not become overly hard due to adequate space on their surface and inside, excellent electrode compressibility, and excellent fast charge / discharge and low-temperature input / output characteristics, the tap density is preferably 1.30 g / cm³. 3 The following is more preferably 1.20 g / cm³ 3 The following is a further preferred value of 1.10 g / cm³. 3the following.

[0417] In this invention, the tap density is set using a powder density meter, where the sample falls through a sieve with a pore size of 300 μm to a diameter of 1.6 cm and a volume of 20 cm³. 3 The cylindrical vibratory container is filled and then vibrated 1000 times with a stroke length of 10 mm. The density value is calculated based on the volume and mass of the sample at this time.

[0418] In this embodiment, the roundness of the carbon material is preferably 0.88 to 0.99, more preferably 0.90 to 0.98, and even more preferably 0.92 to 0.97. Here, considering the reduction of the tortuosity of lithium-ion diffusion, the smoother movement of the electrolyte into the interparticle gaps, and the excellent fast charge / discharge characteristics, the roundness is preferably 0.88 or higher, more preferably 0.90 or higher, and even more preferably 0.92 or higher. Furthermore, considering the ability to ensure the contact between the carbon materials and the excellent cycle characteristics, the roundness is preferably 0.99 or lower, more preferably 0.98 or lower, and even more preferably 0.97 or lower.

[0419] In this specification, roundness is determined by flow particle image analysis to measure the particle size distribution of the equivalent circle diameter, calculated according to the following formula (I).

[0420] Specifically, deionized water was used as the dispersion medium, and polyoxyethylene sorbitan monolaurate was used as the surfactant. The dispersion was obtained by ultrasonic dispersion. Then, the shape of the particles was photographed using a flow-through image analysis device. Based on images obtained from at least 1000 particles, the roundness of particles with an equivalent circular diameter ranging from 1.5 μm to 40 μm was averaged as the roundness.

[0421] [Circularity] = [Circumference of an equivalent circle with the same area as the particle's projected shape] / [Actual circumference of the particle's projected shape] (I)

[0422] In this embodiment, the cumulative micropore volume of the carbon material is preferably 0.030 to 0.120 mL / g, more preferably 0.040 to 0.090 mL / g, and even more preferably 0.050 to 0.070 mL / g. From the viewpoint of easy and moderate deformation during pressing, the aforementioned cumulative micropore volume is preferably 0.030 mL / g or more, more preferably 0.040 mL / g or more, and even more preferably 0.050 mL / g or more. Furthermore, it is preferably 0.120 mL / g or less, more preferably 0.090 mL / g or less, and even more preferably 0.070 mL / g or less.

[0423] In this specification, the cumulative pore volume is determined by mercury porosimetry.

[0424] Specifically, using a mercury porosimeter, a sample weighed to approximately 0.2 g was sealed in a powder container and degassed for 10 minutes at 25°C and below 50 μmHg for pretreatment. Next, the pressure was reduced to 4 psia, and mercury was introduced into the container. The pressure was gradually increased from 4 psia to 40,000 psia, then reduced to 25 psia. The number of pressure increases was set to at least 80 points, and after a 10-second equilibration period in each step, the mercury porosimeter volume was measured. The pore size distribution was calculated using the Washburn equation based on the resulting mercury porosimeter curve. Calculations were performed with a mercury surface tension (γ) of 485 dyne / cm and a contact angle (ψ) of 140°. Based on the results, a graph was constructed with the pore size on the horizontal axis and the pore volume on the vertical axis, and the cumulative pore volume (mL / g) was calculated.

[0425] <Methods for Manufacturing Carbon Materials>

[0426] In this embodiment, commercially available carbon materials can be used as is, or commercially available carbon materials can be processed and used. However, considering the high crystallinity and excellent compressibility, flake-spheroidized natural graphite is preferred.

[0427] It should be noted that when using the carbon materials described in the above-mentioned "Carbon Materials" as carbon materials, carbon materials can be obtained by the methods described in the above-mentioned "Manufacturing Method of Carbon Materials".

[0428] In this embodiment, the preferred raw material for the carbon material is graphite. Considering its high crystallinity and excellent capacity, natural graphite and artificial graphite are more preferred. Considering its even higher crystallinity, even better capacity, and the fact that it does not require heat treatment during manufacturing, natural graphite is further preferred. Graphite with few impurities is preferred, and it is preferable to use it after purification treatment as needed.

[0429] Natural graphite can be categorized into various types, such as earthy graphite, scaly graphite, and flake graphite. Among these natural graphites, scaly graphite and flake graphite are preferred, with flake graphite being even more preferred, considering their high degree of graphitization and low impurity content.

[0430] Examples of artificial graphite include substances obtained by heating organic materials such as coal tar pitch, coal-based heavy oil, atmospheric residue oil, petroleum-based heavy oil, aromatic hydrocarbons, nitrogen-containing cyclic compounds, sulfur-containing cyclic compounds, polystyrene, polyvinyl chloride, polyvinyl alcohol, polyacrylonitrile, polyvinyl butyral, natural polymers, polyphenylene sulfide, polyphenylene ether, furfuryl alcohol resin, phenolic resin, and imide resin to above 2500°C for graphitization.

[0431] Regarding the method of spheroidization, from the perspective of easily controlling the shape of the particles, the method of imparting mechanical energy to spheroidize the particles is preferred.

[0432] Examples of mechanical energy include impact, compression, friction, and shear force. These mechanical energies can be used individually or in combination.

[0433] The method of applying mechanical energy to achieve spherical shape can be achieved simply by using a device that applies mechanical energy.

[0434] Properties of carbon materials containing solidified compounds

[0435] The carbon material content in the carbon material containing the solidified material in this embodiment is preferably 95 to 99.9% by mass, more preferably 98 to 99.7% by mass. From the perspective of excellent capacity as a negative electrode material, the above-mentioned content is preferably 95% by mass or more, more preferably 98% by mass or more, out of 100% by mass of the carbon material containing the solidified material. Furthermore, from the perspective of excellent suppression of volume change within the battery, the above-mentioned content is preferably 99.9% by mass or less, more preferably 99.7% by mass or less.

[0436] The content of the solidified material in the carbon material containing the solidified material in this embodiment is preferably 0.3 to 5% by mass, more preferably 0.5 to 3% by mass. From the perspective of excellent suppression of side reactions within the battery, the above-mentioned content is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, out of 100% by mass of the carbon material containing the solidified material. Furthermore, from the perspective of excellent suppression of battery resistance, the above-mentioned content is preferably 5% by mass or less, more preferably 3% by mass or less.

[0437] The polyoxyalkylene structure content in the carbon material containing the cured product in this embodiment is preferably 0.05 to 3% by mass, more preferably 0.1 to 1.5% by mass. From the perspective of excellent adhesion between the cured product and the carbon material and excellent lithium-ion conductivity, the above-mentioned content is preferably 0.05% by mass or more, more preferably 0.1% by mass or more. Furthermore, from the perspective of excellent suppression of side reactions within the battery, the above-mentioned content is preferably 3% by mass or less, more preferably 1.5% by mass or less.

[0438] The content of polyoxyalkylene structures in carbon materials containing cured materials is the content of 100% by mass in carbon materials containing cured materials.

[0439] The silicon content in the carbon material containing the cured product in this embodiment is preferably 0.03 to 2% by mass, more preferably 0.05 to 1% by mass. From the perspective of excellent durability of the cured product, the above-mentioned content is preferably 0.03% by mass or more, more preferably 0.05% by mass or more. Furthermore, from the perspective of excellent adhesion between the cured product and the carbon material, the above-mentioned content is preferably 2% by mass or less, more preferably 1% by mass or less.

[0440] The silicon content in a carbon material containing solidified material is the content of silicon in 100% by mass of the carbon material containing solidified material.

[0441] The total content of Q units in the carbon material containing the cured material in this embodiment is preferably 0.05 to 2.5% by mass, more preferably 0.1 to 2% by mass. From the perspective of excellent adhesion between the cured material and the carbon material, the above-mentioned total content is preferably 0.05% by mass or more, more preferably 0.1% by mass or more. Furthermore, from the perspective of suppressing peeling caused by shrinkage of the cured material during the production process, the above-mentioned total content is preferably 2.5% by mass or less, more preferably 2% by mass or less.

[0442] The total content of Q units in carbon materials containing solidified substances is the content of 100% by mass of carbon materials containing solidified substances.

[0443] Considering that the higher the crystallinity of graphite, the better its compressibility and the greater its charge / discharge capacity when pressed, the preferred d002 value of the carbon material containing the cured material in this embodiment is... The following is preferred. the following.

[0444] Considering that the higher the crystallinity of graphite, the better its compressibility and the greater its charge / discharge capacity when pressed, the Lc of the carbon material containing the solidified material in this embodiment is preferably... The above is preferred. above.

[0445] The volume-based average particle size (d50) of the carbon material containing the solidified material in this embodiment is preferably 1 to 50 μm, more preferably 4 to 30 μm, and even more preferably 10 to 25 μm. Here, from the perspective of preventing irreversible capacity increase and initial battery capacity loss, the aforementioned volume-based average particle size (d50) is preferably 1 μm or more, more preferably 4 μm or more, and even more preferably 10 μm or more. Furthermore, from the perspective of suppressing process defects such as stripe formation during electrode fabrication and excellent fast charge / discharge characteristics and low-temperature input / output characteristics, the aforementioned volume-based average particle size (d50) is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 25 μm or less.

[0446] In this embodiment, the specific surface area (SA) of the carbon material containing the solidified material is preferably 3.0 to 11.0 m². 2 / g, more preferably 4.0–9.0m 2 / g, more preferably 5.0–8.0m 2 / g. Here, considering the need to ensure lithium-ion exchange, excellent fast charge / discharge characteristics, and low-temperature input / output characteristics, the preferred specific surface area is 3.0 m².2 / g or more, preferably 4.0m 2 / g or more, further preferably 5.0m 2 / g or more. Furthermore, considering the suppression of side reactions with the electrolyte, prevention of decreased initial charge / discharge efficiency, increase in gas generation, and improvement of battery capacity, the specific surface area is preferably 11.0 m². 2 / g or less, preferably 9.0m 2 / g or less, more preferably 8.0m 2 / g or less.

[0447] In this embodiment, the tap density of the carbon material containing the cured material is preferably 0.70–1.30 g / cm³. 3 More preferably, it is 0.80–1.20 g / cm³. 3 More preferably, it is 0.90–1.10 g / cm³. 3 Here, considering the ability to suppress process defects such as stripe formation during electrode fabrication, the ease of forming a high-density negative electrode sheet with good calendering properties due to improved filling, the reduced tortuosity of the lithium ion migration path during electrode body fabrication, the smoother electrolyte movement due to the regular shape of the interparticle gaps, and the improved fast charge / discharge characteristics, the aforementioned tap density is preferably 0.70 g / cm³. 3 The above, more preferably 0.80 g / cm 3 The above is further preferred to be 0.90 g / cm³. 3 The above. Furthermore, considering that the particles do not become overly hard due to adequate space on their surface and inside, excellent electrode compressibility, and excellent fast charge / discharge and low-temperature input / output characteristics, the tap density is preferably 1.30 g / cm³. 3 The following is more preferably 1.20 g / cm³ 3 The following is a further preferred value of 1.10 g / cm³. 3 the following.

[0448] The roundness of the carbon material containing the cured material in this embodiment is preferably 0.88 to 0.99, more preferably 0.90 to 0.98, and even more preferably 0.92 to 0.97. Here, considering the reduction of the tortuosity of lithium-ion diffusion, the smoother movement of the electrolyte into the interparticle gaps, and the excellent fast charge / discharge characteristics, the above-mentioned roundness is preferably 0.88 or higher, more preferably 0.90 or higher, and even more preferably 0.92 or higher. Furthermore, considering the ability to ensure the contact between carbon materials and the excellent cycle characteristics, the above-mentioned roundness is preferably 0.99 or lower, more preferably 0.98 or lower, and even more preferably 0.97 or lower.

[0449] The cumulative pore volume of the carbon material containing the cured product in this embodiment is preferably 0.030 to 0.120 mL / g, more preferably 0.040 to 0.090 mL / g, and even more preferably 0.050 to 0.070 mL / g. From the viewpoint of easy and moderate deformation during pressing, the above-mentioned cumulative pore volume is preferably 0.030 mL / g or more, more preferably 0.040 mL / g or more, and even more preferably 0.050 mL / g or more. Furthermore, it is preferably 0.120 mL / g or less, more preferably 0.090 mL / g or less, and even more preferably 0.070 mL / g or less.

[0450] "negative electrode"

[0451] The negative electrode of this embodiment includes a current collector and a negative electrode active material layer formed on the current collector. The negative electrode active material layer includes at least one carbon material selected from the carbon materials described in the above-mentioned "Carbon Materials" and the carbon materials described in the above-mentioned "Carbon Materials Containing Cured Materials".

[0452] The content of the aforementioned carbon material in the negative electrode active material layer is preferably 80 to 99.8% by mass, more preferably 90 to 99.8% by mass, and even more preferably 99 to 99.7% by mass. Here, from the viewpoint of suppressing the reduction of battery capacity, the above-mentioned content is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 99% by mass or more, and further preferably 99.8% by mass or less, more preferably 99.7% by mass or less.

[0453] In addition to the carbon material of this embodiment, the above-mentioned negative electrode active material layer may also contain conductive additives, binders, thickeners, dispersants, etc.

[0454] The conductive additive can be any conventionally known conductive additive, such as carbon materials other than the carbon material used in this embodiment. Examples of other carbon materials include graphite, and particles formed by coating graphite with amorphous carbon and / or graphitic materials with low graphitization. Other carbon materials may also include oxides and other metals. Examples of other metals include metals capable of alloying with Li, such as Sn, Si, Al, and Bi.

[0455] In addition to the above, other examples of conductive additives include organosilicon and carbon black.

[0456] Conductive additives can be used alone or in combination with two or more.

[0457] The adhesive can be a conventionally known adhesive, such as styrene-butadiene rubber (SBR), which is a water-based adhesive.

[0458] Thickeners and dispersants can be conventionally known thickeners and dispersants, such as carboxymethyl cellulose (CMC).

[0459] The aforementioned negative electrode can be manufactured by forming a negative electrode active material layer on the current collector using the carbon material described in this embodiment. That is, one aspect of the method for manufacturing the negative electrode in this embodiment includes the step of forming a negative electrode active material layer using the carbon material described in the aforementioned "Carbon Material" to obtain the negative electrode. Here, the preferred embodiment of the carbon material is the same as the preferred embodiment of the carbon material described in the aforementioned "Carbon Material".

[0460] Furthermore, one embodiment of the negative electrode manufacturing method includes a step of forming a negative electrode active material layer using the carbon material containing cured material described in the above-mentioned "Carbon Material Containing Cured Material" to obtain a negative electrode. Here, the preferred embodiment of the carbon material containing cured material is the same as the preferred embodiment of the carbon material containing cured material described in the above-mentioned "Carbon Material Containing Cured Material".

[0461] For example, the aforementioned carbon material is dispersed in a dispersion medium with conductive additives, binders, thickeners, etc., to form a slurry. The resulting slurry is then coated onto a current collector to form a negative electrode active material layer.

[0462] From the perspective of low cost and high productivity, the preferred method is to apply a slurry containing the aforementioned carbon material or the aforementioned carbon material containing cured material and a binder onto the current collector and then dry it. A thickener may also be added to the slurry.

[0463] Preferably, a slurry containing the aforementioned carbon material or the aforementioned carbon material containing cured material and a binder is coated onto the current collector and dried, and then pressurized to increase the density of the active material layer formed on the current collector, thereby increasing the battery capacity per unit volume of the active material layer.

[0464] The density of the active material layer is preferably 1.2–2.0 g / cm³. 3 More preferably, it is 1.5–1.8 g / cm³. 3 From the perspective of suppressing the decrease in battery capacity caused by the increase in electrode thickness, the density is preferably 1.2 g / cm³. 3 The above, more preferably 1.5 g / cm³ 3 That's all. Furthermore, considering that the reduced gaps within the electrodes result in a smaller amount of electrolyte held in those gaps, thus decreasing the mobility of alkaline ions such as lithium ions and suppressing the degradation of rapid charge / discharge characteristics, the density is preferably 2.0 g / cm³. 3 The following is more preferably 1.8 g / cm³ 3 the following.

[0465] The dispersion medium can be any conventionally known dispersion medium, such as organic solvents like alcohols and water.

[0466] The current collector can be any known current collector, such as rolled copper foil, electrolytic copper foil, stainless steel foil and other metal films.

[0467] Secondary Batteries

[0468] The carbon material of this embodiment can be used in secondary batteries. The basic structure of a secondary battery, particularly a lithium-ion secondary battery, is the same as that of conventionally known lithium-ion secondary batteries, and typically preferably includes a positive electrode, a negative electrode, and an electrolyte capable of absorbing / releasing lithium ions. The preferred embodiment uses the carbon material of this embodiment in the negative electrode active material layer constituting the negative electrode, and its preferred configuration is the same as the preferred configuration described in the above-described "Negative Electrode" section.

[0469] The positive electrode is formed by forming a layer of positive electrode active material containing positive electrode active material and binder on the current collector, and conventionally known positive electrodes can be used.

[0470] As the electrolyte, known electrolytes can be used. For example, non-aqueous electrolytes prepared by dissolving lithium salts in non-aqueous solvents, or non-aqueous electrolytes prepared into gel, rubber, or solid sheet forms using organic polymers, can be used. Solid electrolytes can also be used.

[0471] In cases where a non-aqueous electrolyte is used as the electrolyte, a porous membrane, such as a porous membrane or non-woven fabric, can be sandwiched between the positive and negative electrodes to prevent short circuits. The membrane can be a conventionally known type. In this case, the non-aqueous electrolyte is impregnated within the porous membrane for use.

[0472] The manufacturing method of the above-mentioned secondary battery includes the process of forming a negative electrode active material layer on a current collector using the carbon material of this embodiment to obtain the above-mentioned negative electrode.

[0473] That is, one embodiment of the secondary battery manufacturing method includes: forming a negative electrode active material layer on a current collector using the carbon material described in the aforementioned "Carbon Materials" to obtain the negative electrode, wherein the secondary battery includes a positive electrode, a negative electrode, and an electrolyte. Here, the preferred embodiment of the carbon material is the same as the preferred embodiment of the carbon material described in the aforementioned "Carbon Materials".

[0474] Furthermore, one embodiment of the secondary battery manufacturing method includes a step of forming a negative electrode active material layer on a current collector using the carbon material containing cured material described in the aforementioned "Carbon Material Containing Cured Material," thereby obtaining the negative electrode. The secondary battery includes a positive electrode, a negative electrode, and an electrolyte. Here, the preferred embodiment of the carbon material containing cured material is the same as the preferred embodiment of the carbon material containing cured material described in the aforementioned "Carbon Material Containing Cured Material."

[0475] "use"

[0476] The negative electrode of the secondary battery using the carbon material of this embodiment described in the above-mentioned "Carbon Materials" can perform stable negative electrode operation, maintain a high initial discharge capacity, and also has good initial efficiency. Therefore, the carbon material of this embodiment is suitable for use as a negative electrode active material for secondary batteries, is more suitable for use as a negative electrode active material for non-aqueous secondary batteries, and is particularly suitable for use as a negative electrode active material for non-aqueous lithium-ion secondary batteries.

[0477] Furthermore, the cured material of this embodiment described in the above-mentioned "Curved Material" can sufficiently reduce the dissolution rate and swelling rate in water and organic solvents. Therefore, the carbon material containing the cured material described in the above-mentioned "Civil Material Containing Cured Material" has excellent suppression of side reactions in the battery, and is more suitable as an active material for the negative electrode of non-aqueous secondary batteries, and is particularly suitable as an active material for the negative electrode of lithium-ion secondary batteries.

[0478] The carbon materials, compositions, cured products, carbon materials containing cured products, negative electrodes, secondary batteries, and their manufacturing methods and modification methods for carbon materials in this embodiment have been described above. However, as one aspect of the present invention, the following related aspects may also be listed.

[0479] Option 1

[0480] [1-1] A carbon material comprising carbon material raw materials and silicon atoms as constituent elements, wherein the atomic concentration of silicon atoms in the carbon material is set as x (atomic %), and the specific surface area of ​​the carbon material is set as y (m²). 2 / g), from x / y (atomic %·g / m) 2 The value represented is 0.3 to 1 atom %·g / m 2 .

[0481] [1-2] According to the carbon material described in [1-1], the integral area of ​​pores with a diameter less than 1 nm, obtained analytically using the grand canonical Monte Carlo (GCMC) method based on molecular simulation, is 0.01 m². 2 / g or less.

[0482] [1-3] The carbon material according to [1-1] or [1-2], wherein the carbon material raw material comprises at least one selected from the group consisting of artificial graphite and natural graphite.

[0483] [1-4] The carbon material according to any one of [1-1] to [1-3], wherein x, as the atomic concentration of the silicon atoms, is 0.1 to 15 atoms.

[0484] [1-5] The carbon material according to any one of [1-1] to [1-4], wherein the specific surface area y is 1 to 15 m. 2 / g.

[0485] [1-6] The carbon material according to any one of [1-1] to [1-5], wherein the Raman R value expressed by the following formula is 0.01 to 0.7.

[0486] Raman R value = (1360 cm⁻¹ in Raman spectroscopy analysis) -1 Nearby peak P B Intensity I B ) / (1580cm in Raman spectroscopy analysis -1 Nearby peak P A Intensity I A )

[0487] [1-7] The carbon material according to any one of [1-1] to [1-6], wherein the carbon material is used in a secondary battery.

[0488] [1-8] A method for manufacturing a carbon material, comprising: setting the atomic concentration of silicon atoms in the carbon material as x (atomic %), and setting the specific surface area of ​​the carbon material as y (m²). 2 / g) when x / y (atomic %·g / m) 2 The value represented is 0.3 to 1 atom %·g / m 2 This is a process of mixing carbon material raw materials with silicon-containing compounds.

[0489] [1-9] According to the method for manufacturing carbon materials described in [1-8], the carbon material raw material comprises at least one selected from the group consisting of artificial graphite and natural graphite.

[0490] [1-10] According to the method for manufacturing carbon materials described in [1-8] or [1-9], the Raman R value of the carbon material raw material, expressed by the following formula, is 0.01 to 0.7.

[0491] Raman R value = (1360 cm⁻¹ in Raman spectroscopy analysis) -1 Nearby peak P B Intensity IB ) / (1580cm in Raman spectroscopy analysis -1 Nearby peak P A Intensity I A )

[0492] [1-11] A method for manufacturing carbon material according to any one of [1-8] to [1-10], wherein the method includes a step of heating the mixture obtained after mixing.

[0493] [1-12] In the method for manufacturing carbon material according to any one of [1-8] to [1-11], x, as the atomic concentration of silicon atoms, is 0.1 to 15 atoms.

[0494] [1-13] The method for manufacturing carbon material according to any one of [1-8] to [1-12], wherein the specific surface area y is 1 to 15 m. 2 / g.

[0495] [1-14] A method for manufacturing a negative electrode, comprising: forming a negative electrode active material layer on a current collector using a carbon material according to any one of [1-1] to [1-7], thereby obtaining a negative electrode.

[0496] [1-15] A method for manufacturing a secondary battery, comprising a positive electrode, a negative electrode and an electrolyte, comprising: forming a negative electrode active material layer on a current collector using a carbon material according to any one of [1-1] to [1-7], thereby obtaining the negative electrode.

[0497] Option 2

[0498] [2-1] A carbon material comprising carbon material raw materials and aluminum atoms as constituent elements, wherein the atomic concentration of the aluminum atoms in the carbon material is set as x (atomic %), and the specific surface area of ​​the carbon material is set as y (m²). 2 / g), from x / y (atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 .

[0499] [2-2] According to the carbon material described in [2-1], wherein the carbon material further comprises phosphorus atoms as constituent elements, and when the atomic concentration of aluminum atoms in the carbon material is set to 1, the atomic concentration of phosphorus atoms in the carbon material is 0.1 to 1.

[0500] [2-3] According to the carbon material described in [2-1] or [2-2], the integral area of ​​pores with a diameter less than 1 nm, obtained analytically by using the grand canonical Monte Carlo (GCMC) method of molecular simulation, is 0.01 m². 2 / g or less.

[0501] [2-4] The carbon material according to any one of [2-1] to [2-3], wherein the carbon material raw material comprises at least one selected from the group consisting of artificial graphite and natural graphite.

[0502] [2-5] The carbon material according to any one of [2-1] to [2-4], wherein x, as the atomic concentration of the aluminum atoms, is 0.1 to 15 atoms.

[0503] [2-6] The carbon material according to any one of [2-1] to [2-5], wherein the specific surface area y is 1 to 15 m². 2 / g.

[0504] [2-7] The carbon material according to any one of [2-1] to [2-6], wherein the Raman R value expressed by the following formula is 0.01 to 0.7.

[0505] Raman R value = (1360 cm⁻¹ in Raman spectroscopy analysis) -1 Nearby peak P B Intensity I B ) / (1580cm in Raman spectroscopy analysis -1 Nearby peak P A Intensity I A )

[0506] [2-8] The carbon material according to any one of [2-1] to [2-7], wherein the carbon material is used in a secondary battery.

[0507] [2-9] A method for manufacturing a carbon material, wherein the atomic concentration of aluminum atoms in the carbon material is set as x (atomic %), and the specific surface area of ​​the carbon material is set as y (m²). 2 / g) when x / y (atomic %·g / m) 2 The value represented is 0.05 to 1 atom %·g / m 2 The method involves mixing carbon material raw materials with aluminum-containing compounds.

[0508] [2-10] According to the method for manufacturing carbon material described in [2-9], a phosphorus-containing compound is also mixed in the mixing process, wherein the atomic concentration of aluminum atoms in the carbon material is set to 1, and the atomic concentration of phosphorus atoms in the carbon material is set to 0.1 to 1.

[0509] [2-11] The method for manufacturing carbon materials according to [2-9] or [2-10], wherein the raw material for carbon materials comprises at least one selected from the group consisting of artificial graphite and natural graphite.

[0510] [2-12] The method for manufacturing carbon material according to any one of [2-9] to [2-11], wherein the Raman R value of the carbon material raw material expressed by the following formula is 0.01 to 0.7.

[0511] Raman R value = (1360 cm⁻¹ in Raman spectroscopy analysis) -1 Nearby peak P B Intensity I B ) / (1580cm in Raman spectroscopy analysis -1 Nearby peak P A Intensity I A )

[0512] [2-13] A method for manufacturing carbon material according to any one of [2-9] to [2-12], wherein the method includes a step of heating the mixture obtained after mixing.

[0513] [2-14] In the method for manufacturing carbon material according to any one of [2-9] to [2-13], x, as the atomic concentration of aluminum atoms, is 0.1 to 15 atoms.

[0514] [2-15] The method for manufacturing carbon material according to any one of [2-9] to [2-14], wherein the specific surface area y is 1 to 15 m. 2 / g.

[0515] [2-16] A method for manufacturing a negative electrode, comprising: forming a negative electrode active material layer on a current collector using a carbon material according to any one of [2-1] to [2-8], thereby obtaining a negative electrode.

[0516] [2-17] A method for manufacturing a secondary battery, comprising a positive electrode, a negative electrode and an electrolyte, comprising: forming a negative electrode active material layer on a current collector using a carbon material according to any one of [2-1] to [2-8], thereby obtaining the negative electrode.

[0517] Option 3

[0518] [3-1] A composition comprising a compound (A) and a crosslinked siloxane compound (B), said compound (A) comprising a polyoxyalkylene structure and said crosslinked siloxane compound (B) comprising a Q unit.

[0519] [3-2] According to the composition described in [3-1], the content of the polyoxyalkylene structure is 10% to 60% by mass.

[0520] [3-3] According to the composition described in [3-1] or [3-2], wherein the total content of Q units is 10% to 50% by mass.

[0521] [3-4] The composition according to any one of [3-1] to [3-3], wherein compound (A) comprises crosslinked silicon units.

[0522] [3-5] The composition according to any one of [3-1] to [3-4], wherein compound (A) comprises a compound having two crosslinked silicon units in one molecule.

[0523] [3-6] The composition according to any one of [3-1] to [3-5], wherein the composition further comprises a solvent.

[0524] [3-7] The composition according to any one of [3-1] to [3-6], wherein the composition further comprises a boron-containing compound (C).

[0525] [3-8] The composition according to any one of [3-1] to [3-7], wherein the composition is a thermosetting composition.

[0526] [3-9] A method for manufacturing a cured product, wherein the composition according to any one of [3-1] to [3-8] is heated.

[0527] [3-10] A method for manufacturing a carbon material containing a solidified material, wherein the composition according to any one of [3-1] to [3-8] is heated in the presence of the carbon material.

[0528] [3-11] A method for manufacturing a carbon material containing a solidified material, wherein the carbon material containing a solidified material obtained by the manufacturing method according to [3-10] is used as a negative electrode active material.

[0529] [3-12] A method for manufacturing a negative electrode, comprising: forming a negative electrode active material layer on a current collector using a carbon material containing a solidified material obtained by the manufacturing method according to [3-10], thereby obtaining a negative electrode.

[0530] [3-13] A method for manufacturing a secondary battery, comprising a positive electrode, a negative electrode and an electrolyte, comprising: forming a negative electrode active material layer on a current collector using a carbon material containing a solidified material obtained by the manufacturing method according to [3-10], thereby obtaining a negative electrode.

[0531] [3-14] A cured material comprising a polyoxyalkylene structure and a three-dimensional siloxane structure comprising Q units.

[0532] [3-15] According to the cured product described in [3-14], the content of the polyoxyalkylene structure is 20% to 80% by mass in 100% by mass of the cured product.

[0533] [3-16] According to the cured product described in [3-14] or [3-15], the silicon content is 10% to 40% by mass in 100% by mass of the cured product.

[0534] [3-17] The cured product according to any one of [3-14] to [3-16], wherein the total content of Q units is 20% to 60% by mass in 100% by mass of the cured product.

[0535] [3-18] A carbon material containing a solidified material, comprising a solidified material and a carbon material according to any one of [3-14] to [3-17].

[0536] [3-19] According to the carbon material containing solidified material described in [3-18], the carbon material containing solidified material is used as a negative electrode active material.

[0537] [3-20] A method for manufacturing a negative electrode, comprising: forming a negative electrode active material layer on a current collector using a carbon material containing a solidified material according to [3-18] to obtain a negative electrode.

[0538] [3-21] A method for manufacturing a secondary battery, comprising a positive electrode, a negative electrode and an electrolyte, comprising: forming a negative electrode active material layer on a current collector using a carbon material containing a solidified material as described in [3-18] to obtain a negative electrode.

[0539] Example

[0540] The present invention will be further described in detail below using examples, but the present invention is not limited to the following examples as long as it does not depart from its spirit.

[0541] Experimental Examples; Carbon Materials

[0542] <Example A1-1>

[0543] The specific surface area of ​​the carbon material raw material is 8.2 m². 210 g of flake-like natural graphite particles with a Raman R value of 0.26 were dispersed in 100 mL of ethanol. 1.5 g of vinyltris(2-methoxyethoxy)silane, a silicon-containing compound, was added to the dispersion, and the mixture was stirred for 30 minutes. After stirring, the ethanol was removed, and the mixture was heated at 150 °C for 1 hour under a nitrogen atmosphere. After cooling, the mixture was successively washed with ethanol and vacuum dried to obtain the carbon material.

[0544] <Comparative Example A1-1>

[0545] The specific surface area of ​​the carbon material raw material is 8.2 m². 2 10 g of flake-like natural graphite particles with a Raman R value of 0.26 were heated at 150 °C for 1 hour under a nitrogen atmosphere. After cooling, the particles were successively cleaned with ethanol and vacuum dried to obtain carbon material.

[0546] <Example A1-2>

[0547] The specific surface area of ​​the carbon material raw material is 1.5 m². 2 10 g of artificial graphite particles with a Raman R value of 0.05 were dispersed in 100 mL of ethanol. 1.5 g of vinyltris(2-methoxyethoxy)silane, a silicon-containing compound, was added to the dispersion, and the mixture was stirred for 30 minutes. After stirring, the ethanol was removed, and the mixture was heated at 150 °C for 1 hour under a nitrogen atmosphere. After cooling, the mixture was successively washed with ethanol and vacuum dried to obtain the carbon material.

[0548] <Comparative Examples A1-2>

[0549] The specific surface area of ​​the carbon material raw material is 1.5 m². 2 10 g of artificial graphite particles with a Raman R value of 0.05 were heated at 150 °C for 1 hour under a nitrogen atmosphere. After cooling, the particles were successively cleaned with ethanol and vacuum dried to obtain the carbon material.

[0550] Experimental Example: Secondary Batteries

[0551] <Examples A2-1, A2-2 and Comparative Examples A2-1, A2-2>

[0552] Using the carbon materials obtained in Examples A1-1, A1-2 and Comparative Examples A1-1, A1-2 as negative electrode active materials, a current collector and a negative electrode on which a layer of negative electrode active material is formed are fabricated.

[0553] Specifically, 98 parts by mass of carbon material, 1 part by mass of carboxymethyl cellulose (CMC), and 2.1 parts by mass of 48% by mass of styrene-butadiene rubber (SBR) aqueous dispersion obtained in Example A1-1 were mixed using a mixer to obtain a slurry.

[0554] The obtained slurry was measured at a unit area weight of 7–8 mg / cm². 2 The material is coated onto a 20 μm thick copper foil, which serves as the current collector, and then dried. The density of the negative electrode active material layer is then adjusted to 1.6–1.7 g / cm³. 3 Using a load sensor The material is rolled and punched into a circle with a diameter of 12.5 mm using a roller press, and then vacuum dried at 90°C for 8 hours to obtain the negative electrode.

[0555] Measurement / Evaluation

[0556] <Atomic concentration of silicon atoms x> (Si) (atom%)>

[0557] atomic concentration x of silicon atoms in carbon materials (Si) (atomic percentage) was measured using an X-ray photoelectron spectroscopy apparatus (KRATOSULTRA2, manufactured by Shimadzu Corporation).

[0558] Specifically, under the following conditions: X-ray source monochromaticization Al-Kα, output 15kV-225W, electron-neutralized filament current, filament bias, charge balance = 0.43V, 1V, 4V, pass energy 160eV in the broad spectrum, 20eV in the narrow spectrum, measurement area 700μm×300μm, extraction angle 90°, and energy correction Si 2p = 103.5eV (SiO2), carbon material as the sample was embedded in indium metal for sampling, and the atomic concentration x of silicon atoms was measured. (Si) (atomic %). The results are shown in Table 1.

[0559] Specific surface area

[0560] The specific surface area of ​​the carbon material was measured using a specific surface area measuring device (Macsorb HM Model-1210, manufactured by Mount Tech Co., Ltd.).

[0561] Specifically, the carbon material used as the sample was pretreated at 150°C under nitrogen flow and then cooled to liquid nitrogen temperature. The specific surface area of ​​the carbon material was determined using the nitrogen adsorption BET single-point method via gas flow, with a nitrogen-helium mixture precisely adjusted to a relative pressure of 0.3 nitrogen relative to atmospheric pressure. The results are shown in Table 1.

[0562] Raman R-value

[0563] Carbon material is allowed to fall naturally into the measuring container of a Raman spectrometer (LabRAM-HR Evolutin, manufactured by Horiba Corporation). Then, an argon-ion laser (wavelength 514.5 nm) is irradiated into the measuring container, and the measuring container is rotated in a plane perpendicular to the laser while the measurement is performed, thereby obtaining the Raman spectrum.

[0564] The measurement conditions are as follows.

[0565] The wavelength of the argon ion laser is 514.5 nm.

[0566] Laser power on the sample: 25mW.

[0567] Resolution: 4cm -1 .

[0568] Measurement range: 1100cm -1 ~1730cm -1 .

[0569] Peak intensity measurement, peak half-width measurement: background processing, smoothing processing (based on simple averaging convolution of 5 points).

[0570] Based on the Raman spectra obtained above, the 1360 cm⁻¹ value was calculated. -1 Nearby peak P B Intensity I B and 1580cm -1 Nearby peak P A Intensity I A Find the value of (intensity I) B / Intensity I A The Raman R value is represented by ).

[0571] <Initial discharge capacity / Initial efficiency>

[0572] The resulting negative electrode and a lithium foil serving as the counter electrode were overlapped through a membrane impregnated with electrolyte to fabricate a battery for charge-discharge testing. The electrolyte was prepared by dissolving LiPF6 in a mixture of ethylene carbonate / ethyl methyl carbonate at a volume ratio of 30 / 70, resulting in a LiPF6 concentration of 1.2 mol / L.

[0573] For the battery used in the charge-discharge test, the initial charge-discharge rate is 0.08 mA / cm. 2 The current density is used to charge the battery until the voltage is 5mV, and then it is charged at a constant voltage of 5mV until the current value is 0.03mA / cm. 2 This is referred to as the initial charge.

[0574] Next, at 0.2 mA / cm 2The battery is discharged at a current density until the voltage reaches 1.5V. This is called the initial discharge.

[0575] Furthermore, the flow of current in the negative electrode of the battery used for charge-discharge testing toward the direction of lithium doping is called "charging," and the flow of current from the negative electrode toward the direction of lithium dedoping is called "discharging."

[0576] Regarding the initial charge capacity / initial discharge capacity (mAh / g), the mass of the negative electrode active material is calculated by subtracting the mass of the copper foil (current collector) cut into the same area as the negative electrode from the total mass of the negative electrode.

[0577] Then, by dividing the initial charging / discharging current capacity by the calculated mass of the negative electrode active material, the initial charging capacity and initial discharging capacity are obtained, and the initial efficiency is calculated using the following formula (II). The results are shown in Table 2.

[0578] Initial efficiency (%) = Initial discharge capacity / Initial charge capacity × 100 (II)

[0579] Experimental Example: Secondary Batteries

[0580] <Example A3-1>

[0581] A methanol solution 1 containing 10% by mass of the same composition as described later in Example C6 was prepared. 10 g of the graphite material obtained in Examples A1-2 was dispersed in 100 mL of methanol to prepare methanol solution 2. 1 g of methanol solution 1 was added to methanol solution 2, and the mixture was stirred for 1 hour. After stirring, the methanol was removed, and the resulting mixture was heated to 120°C to obtain the carbon material containing the cured product of Example A3-1.

[0582] Using the carbon material containing the solidified material obtained above, a negative electrode was obtained in the same manner as in Example A2-1.

[0583] <Example A3-2>

[0584] Add 5g of methanol solution 1 to methanol solution 2, and otherwise obtain a negative electrode in the same manner as in Example A3-1.

[0585] <Example A3-3>

[0586] 10g of the graphite material obtained in Comparative Example A1-2 was dispersed in 100mL of methanol to prepare methanol solution 2. Otherwise, the negative electrode was obtained in the same manner as in Example A3-1.

[0587] The obtained negative electrode and lithium foil serving as the counter electrode were overlapped through a separator impregnated with electrolyte to fabricate a battery for charge-discharge testing. The electrolyte was prepared by dissolving LiPF6 in a mixture of ethylene carbonate / ethyl methyl carbonate (30 / 70, volume ratio) to achieve a LiPF6 concentration of 1.2 mol / L. The results of the initial charge capacity and initial discharge capacity, obtained using the same evaluation method as in Examples A2-1 and A2-2, are shown in Table 3.

[0588] [Table 1]

[0589] Table 1

[0590]

[0591] [Table 2]

[0592] Table 2

[0593]

[0594] [Table 3]

[0595] Table 3

[0596]

[0597] As can be seen from the above results, the x / y ratio of the carbon material in this embodiment is within a specified range, that is, the atomic concentration of silicon atoms on the surface of the carbon material is within an appropriate range. Therefore, when used as the negative electrode of a secondary battery, it can maintain the initial discharge capacity and improve the initial efficiency, and can perform stable negative electrode operation.

[0598] Experimental Examples; Carbon Materials

[0599] <Example B1-1>

[0600] The specific surface area of ​​the carbon material raw material is 8.2 m². 2 10 g of flake-like natural graphite particles with a Raman R value of 0.26 were dispersed in 100 mL of ethanol. 1.5 g of vinylphosphonic acid, a phosphorus-containing compound, was added to the dispersion, and the mixture was stirred for 30 minutes. After stirring, the ethanol was removed, and the mixture was heated at 150 °C for 1 hour under a nitrogen atmosphere. After cooling, the mixture was successively washed with ethanol and vacuum dried to obtain a phosphate-containing carbon material raw material.

[0601] Next, the phosphate-containing carbon material raw material obtained above was dispersed in 80 mL of ethanol. While stirring the dispersion, 20 mL of an ethanol solution containing 0.3 g of ethyl acetoacetate diisopropoxyaluminum was added dropwise. After the addition, the mixture was heated to 40°C and stirred for 1 hour, then the ethanol was removed. The mixture was then heated at 150°C in air for 1 hour and cooled to obtain the carbon material.

[0602] <Example B1-2>

[0603] The specific surface area of ​​the carbon material raw material is 8.2 m². 2 10 g of flake-like natural graphite particles with a Raman R value of 0.26 were dispersed in 100 mL of water. 1 g of ammonium persulfate was added to the dispersion, and the mixture was heated to 40 °C and stirred for 1 hour. After stirring, the powder was separated by filtration and dispersed in 80 mL of ethanol. While stirring the dispersion, 20 mL of an ethanol solution containing 0.3 g of ethyl acetoacetate diisopropoxyaluminum was added dropwise. After the addition, the mixture was heated to 40 °C and stirred for 1 hour, then the ethanol was removed. The mixture was then heated at 150 °C in air for 1 hour and cooled to obtain the carbon material.

[0604] <Comparative Example B1-1>

[0605] The specific surface area of ​​the carbon material raw material is 8.2 m². 2 10 g of flake-like natural graphite particles with a Raman R value of 0.26 were heated at 150 °C for 1 hour under a nitrogen atmosphere. After cooling, the particles were successively cleaned with ethanol and vacuum dried to obtain carbon material.

[0606] <Comparative Examples B1-2>

[0607] The specific surface area of ​​the carbon material raw material is 8.2 m². 2 10 g of flake-like natural graphite particles with a Raman R value of 0.26 were dispersed in 100 mL of ethanol. 1.5 g of vinylphosphonic acid was added to the dispersion, and the mixture was stirred for 30 minutes. After stirring, the ethanol was removed, and the mixture was heated at 150 °C for 1 hour under nitrogen. After cooling, the mixture was washed with ethanol and then vacuum dried to obtain the carbon material.

[0608] Experimental Example: Secondary Batteries

[0609] <Examples B2-1, B2-2 and Comparative Examples B2-1, B2-2>

[0610] Using the carbon materials obtained in Examples B1-1, B1-2 and Comparative Examples B1-1, B1-2 as negative electrode active materials, a current collector and a negative electrode on which a layer of negative electrode active material is formed are fabricated.

[0611] Specifically, 98 parts by mass of carbon material, 1 part by mass of carboxymethyl cellulose (CMC), and 2.1 parts by mass of 48% by mass of styrene-butadiene rubber (SBR) aqueous dispersion obtained in Example B1-1 were mixed using a mixer to obtain a slurry.

[0612] The obtained slurry was measured at a unit area weight of 7–8 mg / cm². 2The material is coated onto a 20 μm thick copper foil, which serves as the current collector, and then dried. The density of the negative electrode active material layer is then adjusted to 1.6–1.7 g / cm³. 3 Using a load sensor The material is rolled and punched into a circle with a diameter of 12.5 mm using a roller press, and then vacuum dried at 90°C for 8 hours to obtain the negative electrode.

[0613] Measurement / Evaluation

[0614] <Atomic concentration of aluminum / phosphorus atoms x> (Al) (atom%)>

[0615] atomic concentration x of aluminum atoms in carbon materials (Al) The atomic concentrations (atomic %) and phosphorus atoms (atomic %) were measured using an X-ray photoelectron spectroscopy apparatus (KRATOS ULTRA2, manufactured by Shimadzu Corporation).

[0616] Specifically, under the following conditions: X-ray source monochromaticization Al-Kα, output 15kV-225W, electron-neutralized filament current, filament bias voltage, charge balance = 0.43V, 1V, 4V, pass energy 160eV in the broad spectrum, 20eV in the narrow spectrum, measurement area 700μm×300μm, extraction angle 90°, and energy correction Si 2p = 103.5eV (SiO2), carbon material as the sample was embedded in indium metal for sampling, and the atomic concentrations (atomic %) of aluminum and phosphorus atoms were determined. The results are shown in Table 4.

[0617] Specific surface area

[0618] The specific surface area of ​​the carbon material was measured using a specific surface area measuring device (Macsorb HM Model-1210, manufactured by Mount Tech Co., Ltd.).

[0619] Specifically, the carbon material used as the sample was pretreated at 150°C under nitrogen flow and then cooled to liquid nitrogen temperature. Furthermore, the specific surface area of ​​the carbon material was determined using the nitrogen adsorption BET single-point method via gas flow, with a nitrogen-helium mixture precisely adjusted to a relative pressure of 0.3 nitrogen relative to atmospheric pressure. The results are shown in Table 4.

[0620] Raman R-value

[0621] Carbon material is allowed to fall naturally into the measuring container of a Raman spectrometer (LabRAM-HR Evolutin, manufactured by Horiba Corporation). Then, an argon-ion laser (wavelength 514.5 nm) is irradiated into the measuring container, and the measuring container is rotated in a plane perpendicular to the laser while the measurement is performed, thereby obtaining the Raman spectrum.

[0622] The measurement conditions are as follows.

[0623] The wavelength of the argon ion laser is 514.5 nm.

[0624] Laser power on the sample: 25mW.

[0625] Resolution: 4cm -1 .

[0626] Measurement range: 1100cm -1 ~1730cm -1 .

[0627] Peak intensity measurement, peak half-width measurement: background processing, smoothing processing (based on simple averaging convolution of 5 points).

[0628] Based on the Raman spectra obtained above, the 1360 cm⁻¹ value was calculated. -1 Nearby peak P B Intensity I B and 1580cm -1 Nearby peak P A Intensity I A Find the value of (intensity I) B / Intensity I A The Raman R value is represented by ).

[0629] <Initial discharge capacity / Initial efficiency>

[0630] The resulting negative electrode and a lithium foil serving as the counter electrode were overlapped through a membrane impregnated with electrolyte to fabricate a battery for charge-discharge testing. The electrolyte was prepared by dissolving LiPF6 in a mixture of ethylene carbonate / ethyl methyl carbonate at a volume ratio of 30 / 70, resulting in a LiPF6 concentration of 1.2 mol / L.

[0631] For the battery used in the charge-discharge test, the initial charge-discharge rate is 0.08 mA / cm. 2 The current density is used to charge the battery until the voltage is 5mV, and then it is charged at a constant voltage of 5mV until the current value is 0.03mA / cm. 2 This is referred to as the initial charge.

[0632] Next, at 0.2 mA / cm 2 The battery is discharged at a current density until the voltage reaches 1.5V. This is called the initial discharge.

[0633] Furthermore, the flow of current in the negative electrode of the battery used for charge-discharge testing toward the direction of lithium doping is called "charging," and the flow of current from the negative electrode toward the direction of lithium dedoping is called "discharging."

[0634] Regarding the initial charge capacity / initial discharge capacity (mAh / g), the mass of the negative electrode active material is calculated by subtracting the mass of the copper foil (current collector) cut into the same area as the negative electrode from the total mass of the negative electrode.

[0635] Then, by dividing the initial charging / discharging current capacity by the calculated mass of the negative electrode active material, the initial charging capacity and initial discharging capacity are obtained, and the initial efficiency is calculated using the following formula (II). The results are shown in Table 5.

[0636] Initial efficiency (%) = Initial discharge capacity / Initial charge capacity × 100 (II)

[0637] [Table 4]

[0638] Table 4

[0639]

[0640] [Table 5]

[0641] Table 5

[0642]

[0643] As can be seen from the above results, the x / y ratio of the carbon material in this embodiment is within a specified range, that is, the atomic concentration of aluminum atoms on the surface of the carbon material is within an appropriate range. Therefore, when used as the negative electrode of a secondary battery, it can maintain the initial discharge capacity and improve the initial efficiency, and can perform stable negative electrode operation.

[0644] Test Examples; Compositions, Cured Products

[0645] <Methods for determining dissolution rate / swelling rate>

[0646] Accurately weigh 0.15 g of the cured product obtained in the examples / comparative examples into a 20 mL glass bottle and record the mass (W). S Next, add 15 mL of deionized water at 23°C using a graduated cylinder, seal the glass bottle tightly, and soak for 1 hour while shaking and mixing every 10 minutes. After 1 hour, remove the solidified material with tweezers, absorb excess water droplets with a paper towel, and accurately weigh it in an aluminum cup on a balance, recording the wet weight (W). W Then, place the cured material, along with the aluminum cup, into a dryer at 110°C and dry for 2–3 hours until constant weight is achieved. After drying, restore the temperature to 23°C in the dryer, weigh it accurately using a balance, and record the dried weight (W). D The dissolution rate of water is calculated using equation (III) below, and the swelling rate of water is calculated using equation (VI) below.

[0647] Regarding the dissolution rate and swelling rate of the organic solvent, the demineralized water was replaced with ethyl methyl carbonate. Otherwise, the same operation as described above was performed.

[0648] Dissolution rate [mass %] = (W S -W D )÷W S ×100(III)

[0649] Swelling percentage [mass %] = (W W -W S )÷W S ×100(VI)

[0650] <raw material>

[0651] Compound (A-1)

[0652] As compound (A-1), bis(3-triethoxysilylpropyl)polyethylene oxide (25-30EO) (product name "SIB1824.84", manufactured by Gelest) is used. Compound (A-1) is an alkoxysilyl compound with T units at both ends of a polyoxyalkylene structure via organic linkages, and has an oxide-to-solids content of 86% by mass.

[0653] The conversion of oxide solids is a calculated value, expressed as a percentage of the molecular weight of the compound relative to the original molecular weight, when all alkoxy groups of the compound are hydrolyzed and completely converted into siloxane bonds.

[0654] Compound (A-2)

[0655] As compound (A-2), N,N'-bis-[(3-triethoxysilylpropyl)aminocarbonyl]polyethylene oxide (10-15EO) (product name "SIB1824.82", manufactured by Gelest). Compound (A-2) is an alkoxysilyl compound with T units at both ends of a polyoxyalkylene structure via organic linkages, and the oxide-to-solids content is 79% by mass.

[0656] Compound (A-3)

[0657] As compound (A-3), N,N'-bis-[(3-triethoxysilylpropyl)aminocarbonyl]polyethylene oxide (7-10EO) (product name "SIB1824.81", manufactured by Gelest). Compound (A-3) is an alkoxysilyl compound with T units at both ends of a polyoxyalkylene structure via organic linkages, and the oxide-to-solids content is 75% by mass.

[0658] Compound (B-1)

[0659] 30.8 parts by mass of a partially hydrolyzed oligomer of tetramethoxysilane composed of silicon in Q units (product name "MKC SilicateMS51"), 62.4 parts by mass of methanol, 0.3 parts by mass of maleic acid as a catalyst, and 6.5 parts by mass of deionized water for hydrolysis were stirred in a sealed container at 23°C for 1 hour to allow for hydrolysis and condensation. The mixture was then allowed to stand at 23°C for 24 hours to obtain compound (B-1). The solid content of compound (B-1) was 16% by mass, converted to SiO2.

[0660] • Manufacturing Example 1: Preparation of a solution of compound (C-1)

[0661] As compound (C-1), phenylboronic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) is used. When using compound (C-1), it is diluted with methanol and used as a 20% by mass methanol solution.

[0662] <Example C1>

[0663] A composition containing methanol as a solvent was prepared by mixing 77 parts by mass of compound (A-1), 207 parts by mass of compound (B-1), and 4 parts by mass of 0.01N acetic acid water for hydrolysis of compound (A-1) with 70% by mass and 30% by mass of solids derived from compound (A-1) in a mixture. The mixture was stirred at 23°C for 3 hours to obtain a composition. The obtained composition was air-dried overnight on an aluminum cup and then dried to constant weight in a desiccator at 120°C to obtain a cured product.

[0664] The evaluation results of the obtained solidified products are shown in Table 6.

[0665] <Examples C2-C6, Comparative Examples C1-C3]

[0666] The types of compound (A), the content of solid components derived from compound (A) in the cured product, the types of compound (B), the content of solid components derived from compound (B) in the cured product, and the types of compound (C) and the content of solid components derived from compound (C) in the cured product were changed as shown in Table 6. Otherwise, the operation was the same as in Example C1 to obtain the cured product.

[0667] The evaluation results of the obtained solidified products are shown in Table 7.

[0668] [Table 6]

[0669] Table 6

[0670]

[0671] [Table 7]

[0672] Table 7

[0673]

[0674] As can be seen from Table 7, the water dissolution rate, organic solvent dissolution rate, water swelling rate, and organic solvent swelling rate of the cured products obtained in Examples C1 to C6, which contain polyoxyalkylene structures and three-dimensional siloxane structures, can all be reduced.

[0675] On the other hand, the water dissolution rate, organic solvent dissolution rate, water swelling rate, and organic solvent swelling rate of the cured products obtained in Comparative Examples C1 to C2, which do not contain the Q unit, cannot be reduced. Furthermore, the water dissolution rate and organic solvent dissolution rate of the cured product obtained in Comparative Example C3, which does not contain the Q unit, can be reduced, but the water swelling rate and organic solvent swelling rate cannot be reduced.

[0676] Furthermore, the present invention has been described in detail with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on and incorporated herein by reference to Japanese patent applications filed on March 13, 2023 (Japanese Patent Application No. 2023-038966), March 13, 2023 (Japanese Patent Application No. 2023-038967), and March 14, 2023 (Japanese Patent Application No. 2023-040025).

[0677] Industrial availability

[0678] The carbon material of this embodiment, when used as a negative electrode active material in a secondary battery, can maintain its initial discharge capacity and improve its initial efficiency, enabling stable negative electrode operation. Therefore, it is suitable for use as a negative electrode active material in secondary batteries, even more suitable for use as a negative electrode active material in non-aqueous secondary batteries, and particularly suitable for use as a negative electrode active material in non-aqueous lithium-ion secondary batteries.

[0679] The cured material of this embodiment can significantly reduce the dissolution rate and swelling rate in water and organic solvents. Therefore, the carbon material containing the cured material exhibits excellent suppression of side reactions within the battery, making it more suitable as an active material for the negative electrode of non-aqueous secondary batteries, and particularly suitable as an active material for the negative electrode of lithium-ion secondary batteries.

Claims

1. A cured product comprising a polyoxyalkylene structure and a three-dimensional siloxane structure having Q units, The swelling rate of the solidified product in ethyl methyl carbonate is less than 70% by mass.

2. The cured product according to claim 1, wherein, The content of the polyoxyalkylene structure in the cured product is 20% to 80% by mass.

3. The cured product according to claim 1, wherein, The silicon atom content in the cured product is 10% to 40% by mass.

4. The cured product according to claim 1, wherein, The total content of the Q units in the cured product is 20% to 60% by mass.

5. The cured product according to claim 1, wherein, Upon hydrolysis, the cured material contains a polyoxyalkylene structure and a segment having at least two silicon atoms in one molecule.

6. A carbon material containing a solidified material, comprising the solidified material and the carbon material according to claim 1.

7. The carbon material containing a solidified product according to claim 6, wherein, The carbon material has modifying components bonded to the carbon material raw material. The modifying component contains at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur, and germanium.

8. The carbon material containing a solidified product according to claim 7, wherein, The modifying component has bonding sites that can bond with carbon materials.

9. The carbon material containing a solidified product according to claim 7, wherein, The molecular weight of the modified component is below 500.

10. The carbon material containing a solidified product according to claim 7, wherein, The modifying component is represented by the following general formula (1), (WITH) n -LW(1) In general formula (1), Z is a group that can chemically bond with carbon materials, W is a group containing at least one element selected from the group consisting of boron, aluminum, silicon, phosphorus, sulfur and germanium, L is a linker, and n is 1 or 2.

11. The carbon material containing a solidified product according to claim 10, wherein, In the general formula (1), W is a group containing silicon.

12. The carbon material containing a solidified product according to claim 10, wherein, Z in the general formula (1) includes a structure that can be added via the Diels-Alder reaction.

13. The carbon material containing a solidified product according to claim 10, wherein, In the general formula (1), Z is a group containing an unsaturated bond at the end.

14. The carbon material containing a solidified product according to claim 10, wherein, In the general formula (1), Z represents vinyl.

15. The carbon material containing a solidified product according to claim 7, wherein, The surface of the carbon material contains carbon-carbon unsaturated bonds and carbon free radical structures.

16. A negative electrode comprising a carbon material containing a solidified material according to any one of claims 6 to 15.

17. A non-aqueous secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the positive and negative electrodes are capable of absorbing and releasing lithium ions. The negative electrode comprises a carbon material containing a solidified material according to any one of claims 6 to 15.

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