Negative electrode active material, electrochemical apparatus and electronic apparatus

Abstract

The present invention relates to an anode active material, an electrochemical device, and an electronic device. The anode active material includes silicon carbide particles and an alumina layer located on the surface of the silicon carbide particles, the silicon carbide particles being SiC. x O y where x and y are 0

Description

[Technical Field]

[0001] This invention relates to the field of energy storage, and more specifically to negative electrode active materials, electrochemical devices, and electronic devices. [Background technology]

[0002] In recent years, silicon has been considered the most likely lithium-ion battery anode material for large-scale use due to its high reversible capacity of 4200 mAh / g. However, silicon expands in volume by approximately 400% during charging and discharging, causing the solid electrolyte interface (SEI) to break down due to this massive expansion. The surface of the fresh material exposed by the interface breakdown continuously consumes the electrolyte, leading to repeated SEI formation. While the capacity of silicon-oxygen materials has decreased to some extent compared to silicon materials, silicon-oxygen materials can significantly reduce volume expansion to some extent. By rationally designing the ratio of silicon to oxygen and particle size in silicon-oxygen materials, and optimizing the battery manufacturing process, the volume expansion of silicon-oxygen materials can be reduced to as little as 120%, but this still cannot satisfy the current demands for high cycle life in lithium-ion batteries. [Overview of the Initiative]

[0003] The present invention provides a negative electrode active material and an electrochemical apparatus containing the negative electrode active material in order to solve problems that exist in the prior art. When the negative electrode active material is used in an electrochemical apparatus, the cycle characteristics of the electrochemical apparatus can be significantly improved.

[0004] In a first embodiment, the negative electrode active material provided in the present invention comprises silicon carbon-oxygen particles and an alumina layer located on the surface of the silicon carbon-oxygen particles, wherein the silicon carbon-oxygen particles are made of SiC x O yIt is shown by , and x and y satisfy 0 < x < 0.04 and 0.8 < y < 1.2. When alumina (Al2O3) on the surface of the carbon silicon oxygen particles reacts with HF generated by the decomposition of the electrolyte, the generation of silicon-hydrogen bonds (Si-H) on the surface of the carbon silicon oxygen particles is suppressed, and furthermore, the aggregation of the carbon silicon oxygen particles can be suppressed. Therefore, the stability of the interface of the carbon silicon oxygen material can be improved, and thereby, the capacity retention rate and the expansion rate of the electrochemical device using the negative electrode active material can be improved.

[0005] According to some embodiments of the present invention, SiC x O y In , x and y satisfy 0.01 ≤ x ≤ 0.035 and 0.85 ≤ y ≤ 1.0. As the x value increases, the carbon content in the negative electrode active material increases and the content of active silicon decreases. Therefore, the gram capacity of the negative electrode active material decreases, and when the same capacity is designed, the cycle capacity retention rate of the electrochemical device decreases and the expansion rate increases. As the x value decreases, the carbon content in the negative electrode active material decreases and the content of active silicon increases. Therefore, the gram capacity of the negative electrode active material increases, but the structural stability deteriorates. When the same capacity is designed, the cycle capacity retention rate of the electrochemical device decreases and the expansion rate increases.

[0006] According to some embodiments of the present invention, the thickness of the alumina layer is 0.5 nm to 10 nm. When the thickness of the alumina layer is thin, the content of Al decreases, the ionic conductivity of the interface is improved, and the gram capacity of the material increases slightly. However, since the alumina layer becomes thin, the resistance effect against HF corrosion weakens, resulting in a decrease in the cycle capacity retention rate of the electrochemical device and an increase in the expansion rate. When the thickness of the alumina layer is thick, the content of Al increases, the ionic conductivity of the interface deteriorates, and the gram capacity of the material decreases. Moreover, when the alumina layer is too thick, the H2O generated by the reaction of Al2O3 and HF increases, so the decomposition of the electrolyte speeds up, more HF is generated, and effective protection of the interface cannot be achieved. Furthermore, the cycle capacity retention rate of the electrochemical device decreases and the expansion rate increases.

[0007] According to some embodiments of the present invention, when the silicon content of the negative electrode active material is a% relative to its mass, a satisfies 45 ≤ a ≤ 70. If the silicon content is too high, the negative electrode active material expands excessively, resulting in poor material cycle properties. If the silicon content is too low, the gram capacity of the negative electrode active material decreases, and consequently, the energy density of the electrochemical apparatus decreases. According to some embodiments of the present invention, when the carbon content of the negative electrode active material is b% relative to its mass, b satisfies 0.9 ≤ b ≤ 11. If the carbon content is too low, the silicon-carbon bond (Si-C) decreases, resulting in poor stability of the negative electrode active material, which in turn reduces the cycle capacity retention rate of the electrochemical apparatus and increases the expansion rate. When the aluminum content of the negative electrode active material is c% relative to its mass, c satisfies 0.04 ≤ c ≤ 1.0. If the aluminum content is too high, the ionic conductivity of the interface deteriorates, resulting in poor cycle properties and expansion properties of the electrochemical apparatus. If the aluminum content is too low, the protective effect on the interface of the carbon-silicon-oxygen material is weakened, resulting in poor cycle and expansion characteristics of the electrochemical apparatus.

[0008] According to some embodiments of the present invention, the silicon content a% and aluminum content c% of the mass of the negative electrode active material satisfy 0.001 ≤ c / a ≤ 0.015. According to some embodiments of the present invention, the carbon content b% and aluminum content c% of the mass of the negative electrode active material satisfy 0.008 ≤ c / b ≤ 0.30.

[0009] According to some embodiments of the present invention, the negative electrode active material has the following properties: (d) the Dv50 of the carbon silicon oxygen particles ranges from 2.5 μm to 10 μm; (e) the particle size distribution of the carbon silicon oxygen particles satisfies 0.3 ≤ Dn10 / Dv50 ≤ 0.6; (f) when the carbon silicon oxygen particles have the highest intensity value I2 in the range of 2θ from 28.0° to 29.0° and the highest intensity value I1 in the range of 2θ from 20.5° to 21.5° in the X-ray diffraction pattern, I2 and I1 satisfy 0 < I2 / I1 ≤ 1; and (g) the specific surface area of the carbon silicon oxygen particles is at least one of 1 m 2 / g to 50 m 2 / g.

[0010] According to some embodiments of the present invention, the powder electrical conductivity of the negative electrode active material is from 2.0 S / cm to 30 S / cm.

[0011] According to some embodiments of the present invention, the negative electrode active material further contains graphite. By adding graphite to the negative electrode active material, the gram capacity of the negative electrode active material can be increased. In some embodiments, the graphite includes at least one of natural graphite, artificial graphite, and mesocarbon microbeads.

[0012] According to some embodiments of the present invention, the method for preparing the negative electrode active material includes a step of subjecting a carbon silicon oxygen material and an aluminum source to a deposition reaction to obtain a reaction product, and a step of firing the reaction product.

[0013] According to some embodiments of the present invention, the firing temperature is 300°C to 800°C. When the firing temperature decreases, the bonding ability between aluminum-oxygen bonds (Al-O) weakens, and the stability of alumina on the surface of the negative electrode active material deteriorates. As a result, the protective effect of alumina on the interface deteriorates, and furthermore, the cycle capacity retention rate of the electrochemical apparatus decreases while the expansion rate improves. When the firing temperature increases, the bonding ability between silicon-oxygen bonds (Si-O) strengthens, and a crystallization phenomenon occurs. As a result, the stress distribution during the cycle process becomes non-uniform, more new interfaces are created, and furthermore, the cycle capacity retention rate of the electrochemical apparatus decreases while the expansion rate improves.

[0014] According to some embodiments of the present invention, the firing time is 1 to 5 hours. If the firing time is too short, the bond strength between Al and O becomes insufficient, resulting in poor stability of the alumina on the surface. Consequently, the protective effect of alumina on the interface deteriorates, and the capacity retention rate of the electrochemical apparatus decreases while the expansion rate increases. If the firing time is too long, the silicate phase increases, the bond strength of the silicon-silicon bond (Si-Si) weakens, while the bond strength of the Si-O bond increases. Consequently, the structural stability of the material deteriorates, resulting in a decrease in the capacity retention rate of the electrochemical apparatus and an expansion rate increasing.

[0015] In a second embodiment, the present invention provides an electrochemical apparatus comprising a negative electrode containing the negative electrode active material described in the first embodiment. According to some embodiments of the present invention, the sheet resistance of the negative electrode is 0.2Ω to 1Ω.

[0016] In a third aspect, the present invention provides an electronic apparatus including an electrochemical apparatus described in a second aspect of the present invention.

[0017] The present invention provides a negative electrode active material. In this negative electrode active material, an alumina layer is present on the surface of a carbon-doped silicon-oxygen material. This alumina layer is used to protect the interface of the silicon material from corrosion by HF, etc., thereby effectively improving the interfacial stability of the material and further improving the cycle characteristics of an electrochemical apparatus containing this active material. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a schematic diagram of the structure of a negative electrode active material according to one embodiment of the present invention, where 1 represents SiCxOy and 2 represents the alumina layer. [Figure 2] Figure 2 is an EDS layered image of the negative electrode active material in Example 1 of the present invention. [Figure 3] Figure 3 shows the XRD pattern of the negative electrode active material in Example 1 of the present invention. [Figure 4] Figure 4 is a comparison chart of the capacity retention rate and cycle expansion of lithium-ion batteries in Example 1 and Comparative Example 1, where 3 represents Example 1 and 4 represents Comparative Example 1. [Modes for carrying out the invention]

[0019] Hereinafter, the technical proposal according to the present invention will be clearly and completely described with reference to examples in order to provide a clearer understanding of the object, technical proposal and advantages of the present invention. Obviously, the examples described are not all examples, but only a selection of examples of the present invention. The relevant examples described herein are illustrative and are used to provide a basic understanding of the present invention. The examples of the present invention should not be construed as limiting the present invention.

[0020] For the sake of brevity, only a few numerical ranges are specifically disclosed in this invention. However, any lower limit may be combined with any upper limit to form an unexpressed range, and any lower limit may be combined with other lower limits to form an unexpressed range, and similarly, any upper limit may be combined with any other upper limit to form an unexpressed range. Furthermore, each point or individual numerical value disclosed individually may, as a lower or upper limit, be combined with any other point or individual numerical value, or with other lower or upper limits, to form an unexpressed range.

[0021] In this specification, "above" and "below" are inclusive of those numbers unless otherwise specified.

[0022] Unless otherwise specified, the terms used in this invention have the general meanings commonly understood by those skilled in the art. Unless otherwise specified, the values ​​of each parameter mentioned in this invention can be measured using various measurement methods commonly used in the art (for example, they can be measured according to the methods described in the embodiments of this invention).

[0023] The terms “at least one of,” “at least one of,” “at least one kind of,” or other similar terms used to connect lists of items mean any combination of the listed items. For example, if items A and B are listed, the expression “at least one of A and B” means A only, B only, or A and B. In other specific examples, if items A, B, and C are listed, the expression “at least one of A, B, and C” means A only, B only, C only, A and B (excluding C), A and C (excluding B), B and C (excluding A), or all of A, B, and C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.

[0024] 1.Negative electrode active material In a first embodiment, the negative electrode active material provided in the present invention comprises silicon carbon-oxygen particles and an alumina layer located on the surface of the silicon carbon-oxygen particles, wherein the silicon carbon-oxygen particles are made of SiC x O yIt is shown by , where x and y satisfy 0 < x < 0.04 and 0.8 < y < 1.2. When alumina on the surface of the carbon silicon oxygen particles reacts with HF generated by the decomposition of the electrolyte, the generation of silicon hydrogen bonds (Si-H) on the surface of the carbon silicon oxygen particles is suppressed, and further, the aggregation of the carbon silicon oxygen particles can be suppressed. Therefore, the stability of the interface of the carbon silicon oxygen material can be improved, thereby improving the capacity retention rate and expansion rate of the electrochemical device using the negative electrode active material.

[0025] According to some embodiments of the present invention, SiC x O y In , x is 0.005, 0.015, 0.017, 0.02, 0.023, 0.025, 0.027, 0.03, 0.033, 0.037, or a range consisting of any two of these numerical values. In some embodiments, x satisfies 0.01 ≤ x ≤ 0.035. According to some embodiments of the present invention, SiC x O y In , y is 0.87, 0.90, 0.93, 0.95, 0.97, 1.05, 1.1, 1.15, or a range consisting of any two of these numerical values. In some embodiments, y satisfies 0.85 ≤ y ≤ 1.0. As the x value increases, the carbon content in the negative electrode active material increases and the content of active silicon decreases. Therefore, the gram capacity of the negative electrode active material decreases, and when the same capacity is designed, the cycle capacity retention rate of the electrochemical device decreases and the expansion rate increases. As the x value decreases, the carbon content in the negative electrode active material decreases and the content of active silicon increases. Therefore, the gram capacity of the negative electrode active material increases, but the structural stability deteriorates. When the same capacity is designed, the cycle capacity retention rate of the electrochemical device decreases and the expansion rate increases.

[0026] According to some embodiments of the present invention, the thickness of the alumina layer is 0.5 nm to 10 nm. In some embodiments, the thickness of the alumina layer is in the range of 1.5 nm, 2.5 nm, 3 nm, 4 nm, 5.5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or any two of these values. A thinner alumina layer reduces the Al content, improves the ionic conductivity of the interface, and slightly increases the gram capacity of the material. However, because the alumina layer is thinner, the resistance effect against HF corrosion is weakened, resulting in a decrease in the capacity retention rate of the electrochemical device and an increase in the expansion rate. A thicker alumina layer increases the Al content, worsens the ionic conductivity of the interface, and decreases the gram capacity of the material. To some extent, if the alumina layer is too thick, the amount of H2O produced by the reaction of Al2O3 and HF increases, leading to faster decomposition of the electrolyte, the generation of more HF, inability to achieve effective protection of the interface, and further, a decrease in the capacity retention rate of the electrochemical device and an increase in the expansion rate.

[0027] According to some embodiments of the present invention, when the silicon content of the negative electrode active material is a% relative to the mass, a satisfies 45 ≤ a ≤ 70. In some embodiments, a is in the range of 48, 52, 55, 57, 59, 62, 64, 66, or any two of these values. In some embodiments, a satisfies 50 ≤ a ≤ 65. If the silicon content is too high, the negative electrode active material expands excessively, resulting in poor material cycling properties. If the silicon content is too low, the gram capacity of the negative electrode active material decreases, and consequently, the energy density of the electrochemical apparatus decreases.

[0028] According to some embodiments of the present invention, when the carbon content of the negative electrode active material is b% relative to the mass, b satisfies 0.9 ≤ b ≤ 11. In some embodiments, b is in the range of 0.98, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10.5, or any two of these values. In some embodiments, b satisfies 1 ≤ b ≤ 10. If the carbon content is too low, the silicon-carbon (Si-C) bonds decrease, resulting in poor stability of the negative electrode active material and consequently poor cycle and expansion characteristics of the electrochemical apparatus.

[0029] According to some embodiments of the present invention, when the aluminum content of the negative electrode active material is c% relative to the mass, c satisfies 0.04 ≤ c ≤ 1.0. In some embodiments, c is in the range of 0.07, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or any two of these values. In some embodiments, c satisfies 0.05 ≤ c ≤ 0.8. If the aluminum content is too high, the ionic conductivity of the interface deteriorates, resulting in poor cycle and expansion characteristics of the electrochemical apparatus. If the aluminum content is too low, the protective effect on the interface of the carbon-silicon-oxygen material is weakened, similarly resulting in poor cycle and expansion characteristics of the electrochemical apparatus.

[0030] According to some embodiments of the present invention, the silicon content a% and aluminum content c% of the mass of the negative electrode active material satisfy the condition 0.001 ≤ c / a ≤ 0.015. In some embodiments, c / a is in the range of 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.12, 0.13, 0.145, or any two of these values. In some embodiments, a and c satisfy the condition 0.001 ≤ c / a ≤ 0.014.

[0031] According to some embodiments of the present invention, with respect to the mass of the negative electrode active material, the content b% of carbon element and the content c% of aluminum element satisfy 0.008 ≤ c / b ≤ 0.30. In some embodiments, c / b is 0.01, 0.03, 0.05, 0.07, 0.09, 0.1, 0.13, 0.15, 0.17, 0.19, 0.2, 0.23, 0.25, 0.27, 0.29, or a range consisting of any two of these numerical values. In some embodiments, c and b satisfy 0.01 ≤ c / b ≤ 0.29.

[0032] According to some embodiments of the present invention, the range of Dv50 of the carbon silicon oxygen particles is 2.5 μm to 10 μm. In some embodiments, Dv50 of the carbon silicon oxygen particles is 2.5 μm, 3.0 μm, 4.0 μm, 4.5 μm, 5.5 μm, 6.0 μm, 7.0 μm, 8.0 μm, or a range consisting of any two of these numerical values. In the present invention, Dv50 is the particle diameter corresponding when the cumulative volume percentage of the particles reaches 50%.

[0033] According to some embodiments of the present invention, the particle size distribution of the carbon silicon oxygen particles satisfies 0.3 ≤ Dn10 / Dv50 ≤ 0.6. For example, Dn10 / Dv50 is 0.35, 0.4, 0.45, 0.5 or 0.55, etc. In the present invention, Dn10 is the particle diameter corresponding when the cumulative number percentage of the particles reaches 10%.

[0034] According to some embodiments of the present invention, for the carbon silicon oxygen particles, in the X-ray diffraction pattern, when the highest intensity value in the range of 2θ being 28.0° to 29.0° is I2 and the highest intensity value in the range of 2θ being 20.5° to 21.5° is I1, I2 and I1 satisfy 0 < I2 / I1 ≤ 1. According to some embodiments of the present invention, the specific surface area of the carbon silicon oxygen particles is 1 m 2 / g to 50 m 2 / g. In some embodiments, the specific surface area of the carbon silicon oxygen particles is 1 m 2 / g, 10 m 2 / g, 20 m 2 / g, 30 m2 / g, 40m 2 / g, 45m 2 / g, or a range consisting of any two of these values.

[0035] According to some embodiments of the present invention, the powder electrical conductivity of the negative electrode active material is 2.0 S / cm to 30 S / cm. In some embodiments, the powder electrical conductivity of the negative electrode active material is in the range of 3.0 S / cm, 5.0 S / cm, 7.0 S / cm, 10 S / cm, 15 S / cm, 20 S / cm, 25 S / cm, or any two of these values.

[0036] According to some embodiments of the present invention, the negative electrode active material further comprises graphite. By adding graphite to the negative electrode active material, the gram capacity of the negative electrode active material can be increased. In some embodiments, the graphite comprises at least one of natural graphite, artificial graphite, and mesocarbon microbeads.

[0037] II. Method for preparing the negative electrode active material The method for preparing a negative electrode active material according to the present invention includes the steps of depositing a silicon-carbon-oxygen material and an aluminum source to obtain a reaction product, and calcining the reaction product.

[0038] According to some embodiments of the present invention, the firing temperature is 300°C to 800°C. In some embodiments, the firing temperature is in the range of 350°C, 430°C, 450°C, 470°C, 490°C, 510°C, 530°C, 550°C, 570°C, 590°C, 610°C, 630°C, 650°C, 670°C, 690°C, 710°C, 730°C, 750°C, 770°C, or any two of these values. In some embodiments, the firing temperature is 400°C to 700°C. As the firing temperature decreases, the bonding ability between Al and O weakens, the stability of Al2O3 on the surface of the negative electrode active material deteriorates, resulting in a reduced protective effect of Al2O3 on the interface, and furthermore, the capacity retention rate of the electrochemical apparatus decreases while the expansion rate improves. As the firing temperature increases, the bonding ability between Si and O strengthens, leading to crystallization. As a result, the stress distribution during the cycle process becomes non-uniform, creating more new interfaces. Furthermore, the capacity retention rate of the electrochemical apparatus decreases while the expansion rate improves.

[0039] According to some embodiments of the present invention, the firing time is 1 to 5 hours. In some embodiments, the firing time is 1.3 hours, 1.5 hours, 1.7 hours, 1.9 hours, 2.0 hours, 2.3 hours, 2.5 hours, 2.7 hours, 2.9 hours, 3.1 hours, 3.3 hours, 3.5 hours, 3.7 hours, 4.0 hours, 4.2 hours, 4.5 hours, 4.7 hours, or a range consisting of any two of these values. In some embodiments, the firing time is 1.5 to 4.5 hours. If the firing time is too short, the bond strength between Al and O will be insufficient, resulting in poor Al-O bonding and reduced stability of Al2O3 on the surface. As a result, the protective effect of Al2O3 on the interface will be poor, and furthermore, the capacity retention rate of the electrochemical apparatus will decrease while the expansion rate will increase. If the firing time is too long, the silicate phase increases, weakening the Si-Si bond strength and strengthening the Si-O bond strength. As a result, the structural stability of the material deteriorates, leading to a decrease in the capacity retention rate of the electrochemical apparatus and an increase in the expansion rate.

[0040] According to some embodiments of the present invention, the deposition reaction is a chemical deposition method known in the art, such as chemical vapor deposition (ALD) or chemical liquid deposition. In ALD, chemical reactants (e.g., trimethylaluminum and aqueous gas) are introduced into the reaction chamber in gaseous form and reach the reactor in pulse form. The reactants are then dispersed from one another by a flow of purge gas or pumping. Each pulse of reactant chemically reacts with the surface of the particles, and as a result, the ALD can be uniformly coated while growing precisely in a single layer by a self-limiting process.

[0041] According to some embodiments of the present invention, the aluminum source comprises at least one of trimethylaluminum, triethylaluminum, and isopropylaluminum.

[0042] According to some embodiments of the present invention, a method for preparing a carbon-silicon-oxygen material includes the steps of heating raw materials for generating SiO gas and introducing a carbon source such as acetylene in the range of 600°C to 1100°C.

[0043] III. Electrochemical apparatus The electrochemical apparatus provided in the present invention includes a negative electrode, the negative electrode comprising the negative electrode active material described in the first embodiment. According to some embodiments of the present invention, the sheet resistance of the negative electrode is 0.2Ω to 1Ω.

[0044] According to some embodiments of the present invention, the negative electrode comprises a negative electrode current collector and a negative electrode active material layer provided on the surface of the negative electrode current collector, wherein the negative electrode active material layer comprises the negative electrode active material described in the first embodiment. In some embodiments, the negative electrode active material layer further comprises a binder, which may include various binder polymers. In some embodiments, the binder comprises at least one of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylic acid ester, polyacrylic acid, polyacrylate, sodium carboxymethylcellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, and styrene-butadiene rubber. In some embodiments, the negative electrode active material layer further comprises a conductive material to improve the electrical conductivity of the electrode. Any conductive material can be used as this conductive material, as long as it does not undergo chemical changes. In some embodiments, the conductive material includes at least one of conductive carbon black, acetylene black, carbon nanotubes, Ketjen black, conductive graphite, and graphene.

[0045] According to some embodiments of the present invention, the negative electrode current collector includes copper foil, nickel foil, stainless steel foil, titanium foil, foamed nickel, foamed copper, a polymer substrate coated with a conductive metal, or a combination thereof.

[0046] According to some embodiments of the present invention, the electrochemical apparatus further includes a positive electrode, the positive electrode comprising a current collector and a positive electrode active material layer located on the current collector.

[0047] According to some embodiments of the present invention, the positive electrode active material includes, but is not limited to, lithium cobalt oxide (LiCoO2), lithium nickel cobalt manganese (NCM) ternary material, lithium iron phosphate (LiFePO4), or lithium manganese oxide (LiMn2O4).

[0048] According to some embodiments of the present invention, the positive electrode active material layer further comprises a conductive agent and a binder. In some embodiments, the binder includes, but is not limited to, polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (esterified) styrene-butadiene rubber, epoxy resin, or nylon. In some examples, the conductive agent includes, but is not limited to, carbon-based materials, metallic materials, conductive polymers, and mixtures thereof. In some examples, the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, and any combination thereof. In some examples, the metallic material is selected from metal powder, metal fiber, copper, nickel, aluminum, and silver. In some examples, the conductive polymer is a polyphenylene derivative.

[0049] According to some embodiments of the present invention, the positive electrode current collector can be a metal foil or a composite current collector. For example, aluminum foil can be used. A composite current collector can be formed by forming a metal material (such as copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys) on a polymer substrate.

[0050] The positive electrode in this invention can be manufactured by methods known in the art. Generally, a positive electrode material, along with a selectable conductive agent (e.g., carbon material such as carbon black and metal particles), a binder (e.g., SBR), and other selectable additives (e.g., PTC thermistor material) are mixed, dispersed in a solvent (e.g., deionized water), uniformly stirred, and then uniformly coated onto a positive electrode current collector. After drying, a positive electrode having a positive electrode sheet is obtained.

[0051] According to some embodiments of the present invention, the electrochemical apparatus further comprises an electrolyte or a solid electrolyte.

[0052] According to some embodiments of the present invention, the electrolyte that can be used in the embodiments of the present invention may be an electrolyte known in the prior art.

[0053] In some examples, the electrolyte comprises an organic solvent, a lithium salt, and an additive. The organic solvent in the electrolyte according to the present invention may be any organic solvent known in the prior art that can be used as a solvent for the electrolyte. The electrolyte used in the electrolyte according to the present invention is not limited and may be any electrolyte known in the prior art. The additive in the electrolyte according to the present invention may be any additive known in the prior art that can be used as an additive for the electrolyte. In some examples, the organic solvent comprises, but is not limited to, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate, or ethyl propionate. In some examples, the organic solvent comprises an ether-based solvent, for example, at least one of 1,3-dioxolane (DOL) and ethylene glycol dimethyl ether (DME). In some examples, the lithium salt comprises at least one of an organolithium salt and an inorganic lithium salt. In some examples, the lithium salt includes, but is not limited to, lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium difluorophosphate (LiPO2F2), lithium bis(trifluoromethanesulfonyl)imide (LiN(CF3SO2)2) (LiTFSI), lithium bis(fluorosulfonyl)imide (Li(N(SO2F)2)) (LiFSI), lithium bis(oxalato)borate (LiB(C2O4)2) (LiBOB), or lithium difluoro(oxalato)borate (LiBF2(C2O4)) (LiDFOB).

[0054] According to some embodiments of the present invention, the solid electrolyte is Li2+x Al 2+x Si 1-x S6(0≦x<1), Li3YCl6, Li3YBr6, Li3OCl, LiPON, Li 0.5 La 0.5 TiO3, Li 1+x Al x Ti 2-x (PO4)3, Li7La3Zr2O 12 Li 10 GeP2S 12 (LGPS), Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Li 3.25 Ge 0.25 P 0.75 S4, Li 11 AlP2S 12 , and Li7P3S 11 It includes at least one of the following.

[0055] According to some embodiments of the present invention, the electrochemical apparatus is provided with a separator between the positive and negative electrodes to prevent short circuits. The material and shape of the separator used in the embodiments of the present invention are not particularly limited and may be any technology disclosed in the prior art. In some embodiments, the separator includes a polymer or inorganic material formed from a material stable with respect to the electrolyte of the present invention. For example, the separator may include a base layer and a surface treatment layer. The base layer is a nonwoven fabric, film, or composite film having a porous structure. The material of the base layer includes at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyimide. Specifically, the base layer can be selected from a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite membrane. A surface treatment layer is provided on at least one surface of the base layer, and the surface treatment layer may be a polymer layer or an inorganic layer, or a layer obtained by mixing a polymer and an inorganic material. The inorganic layer comprises inorganic particles and a binder. The inorganic particles include at least one of the following: aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium oxide, tin oxide, cerium oxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and barium sulfate. The binder includes at least one of the following: polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylic acid ester, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, and polyhexafluoropropylene. The polymer layer comprises a polymer. The polymer material includes at least one of the following: polyamide, polyacrylonitrile, polyacrylic acid ester, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride, and poly(vinylidene fluoride-hexafluoropropylene).

[0056] According to some embodiments of the present invention, the electrochemical apparatus of the present invention includes, but is not limited to, all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In some embodiments, the electrochemical apparatus is a lithium secondary battery. In some embodiments, the lithium secondary battery includes, but is not limited to, lithium metal secondary batteries, lithium ion secondary batteries, lithium polymer secondary batteries, or lithium ion polymer secondary batteries.

[0057] 4.Electronic equipment The electronic device of the present invention may be any device that uses an electrochemical device according to a third aspect of the present invention.

[0058] In some embodiments, the electronic devices include, but are not limited to, laptop computers, pen-input computers, mobile computers, e-book players, mobile phones, portable fax machines, portable copiers, portable printers, headphone stereos, video camcorders, LCD televisions, handheld vacuum cleaners, portable CDs, MiniDiscs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, mopeds, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, strobes, cameras, large household storage batteries or lithium-ion capacitors, and the like.

[0059] Examples and Comparative Examples 1.SiC x O y Preparation of Al2O3 material Step 1: SiC x O y The material was placed in the processing chamber of the fluidized bed system, and the pressure inside the processing chamber was extracted to be within the range of 0.3 mbar to 0.5 mbar. Step 2: Using deionized water, pulses were applied for 0.1s to 0.5s, for example, 0.3s, followed by an adsorption reaction for 30s to 90s, for example, 60s. After that, excess water was purged using an inert gas. Step 3: Pulsation was performed using trimethylaluminum for 3 to 10 seconds, for example 5 seconds, followed by an adsorption reaction for 30 to 90 seconds, for example 60 seconds, after which excess trimethylaluminum was purged with an inert gas. Step 4: Using deionized water, pulses were applied for 0.1s to 0.5s, for example, 0.3s, followed by an adsorption reaction for 30s to 90s, for example, 60s. After that, excess water was purged using an inert gas. Step 5: SiC x O y Steps 2 to 4 were repeated until a nano-coating layer of a certain thickness was formed on the surface of the material. Step 6: In an Ar atmosphere, the powder obtained in Step 5 is fired at a constant temperature for a constant time to form SiC x O y I obtained the Al2O3 material.

[0060] Here, SiC x O y In the preparation of the material, raw materials for generating SiO gas are heated, and acetylene is introduced within the range of 600°C to 1100°C, and SiC x O y The process included a step of obtaining the materials. Here, the values ​​of x and y were adjusted by adjusting the raw materials and acetylene content for generating SiO gas.

[0061] 2. Preparation of lithium-ion batteries SiC x O y Al2O3 material and graphite were mixed in a fixed ratio to obtain a mixed powder with a designed mixed gram capacity of 850 mAh / g. The mixed powder, conductive agent acetylene black, and PAA were thoroughly stirred and mixed in a deionized water solvent system in a weight ratio of 95:1.2:3.8. The mixture was then coated onto a Cu foil, dried, and cold-pressed to obtain a negative electrode sheet.

[0062] A positive electrode slurry was prepared by uniformly dispersing the positive electrode active material LiCoO2, the conductive agent carbon black Super-P, and the binder polyvinylidene fluoride (abbreviated as PVDF, with polyvinylidene fluoride accounting for 10% of the binder's mass) in the solvent N-methylpyrrolidone. The solid content of the positive electrode slurry was 75%, consisting of 96% lithium cobalt oxide, 2% PVDF, and 2% conductive carbon black Super-P. The positive electrode slurry was uniformly applied to the aluminum foil of the positive electrode current collector, dried, and then cold-pressed to obtain a positive electrode sheet.

[0063] Under a dry argon atmosphere, a solvent mixture of propylene carbonate (PC), ethylene carbonate (EC), and diethyl carbonate (DEC) (by weight ratio approximately 1:1:1) was mixed with LiPF6 at a concentration of 1.15 mol / L and homogeneously mixed. Then, fluoroethylene carbonate (FEC) at a concentration of approximately 7.5% was added and homogeneously mixed to obtain an electrolyte.

[0064] A porous PE polymer film was used as the separator. The positive electrode sheet, separator, and negative electrode sheet were laminated in this order and wound together to obtain an electrode assembly, with the separator positioned between the positive electrode sheet and the negative electrode sheet to act as an isolation. The electrode assembly was placed in an outer casing, the prepared electrolyte was injected, and the assembly was sealed. A lithium-ion battery was then obtained through a process flow including chemical conversion, degassing, and trimming.

[0065] Example 1 Step 1: SiC x O y The material was placed in the processing chamber of the fluidized bed system, and the pressure inside the processing chamber was extracted to be within the range of 0.3 mbar to 0.5 mbar. Step 2: A pulse was applied using deionized water for 0.3 s, followed by an adsorption reaction for 60 s. After that, excess water was purged using an inert gas. Step 3: Pulsation was performed using trimethylaluminum for 5 s, followed by an adsorption reaction for 60 s, and then excess trimethylaluminum was purged with an inert gas. Step 4: A pulse was applied using deionized water for 0.3 s, followed by an adsorption reaction for 60 s. After that, excess water was purged using an inert gas. Step 5: SiC x O y Steps 2 to 4 were repeated until a 1 nm nano-coating layer was formed on the surface of the material. Step 6: In an Ar atmosphere, the powder obtained in Step 5 is calcined at a temperature of 600°C for 3 hours to form SiC x O y I obtained the Al2O3 material. Step 7: The method for manufacturing the lithium-ion battery was the same as the method described in "II. Preparation of Lithium-ion Battery".

[0066] SiC x O y In Al2O3, x was 0.015, y was 0.95, and the thickness of the Al2O3 layer on the surface was 1 nm. The negative electrode active material was SiC. x O y In Al2O3, the Si content was 60%, the carbon content was 3.3%, and the Al content was 0.086%. The ratio of Al to Si was 0.0014, and the ratio of Al to C was 0.026.

[0067] SiC x O y The values ​​are as follows: Dv50 is 5.7 μm, Dn10 / Dv50 ratio is 0.49, I2 / I1 is 0.78, and BET is 1.78 m 2 It was / g.

[0068] SiC x O y The gram capacity of the Al2O3 material powder was 1505 mAh / g, the capacity retention rate after 400 cycles of the lithium-ion battery was 92.5%, and the expansion rate was 9%.

[0069] Examples 2 to 5 SiC x O yThe preparation process of the Al2O3 material and the manufacturing process of the lithium-ion battery followed Example 1, but the difference was that the thickness of the Al2O3 layer formed in step 5 differed in Examples 2 to 5. Details are shown in Table 1.

[0070] Examples 6 to 10 SiC x O y The preparation process for the Al2O3 material and the manufacturing process for the lithium-ion battery followed Example 1, but the difference was that in Examples 6 to 9, the firing temperature in the Ar atmosphere in step 6 was different. Details are shown in Table 2. In Example 10, the firing time in the Ar atmosphere in step 6 was different. Details are shown in Table 2.

[0071] Examples 11-12 SiC x O y The preparation process of the Al2O3 material and the manufacturing process of the lithium-ion battery were described in Example 1, but the difference is that the SiC used in Examples 11 and 12 was different. x O y The difference was that... Details are shown in Table 3.

[0072] Comparative Example 1 Step 1: SiC under Ar atmosphere x O y The material was fired at a temperature of 600°C for 3 hours, and after high-temperature treatment, x was 0.002 and y was 0.98. x O y I obtained the materials. Step 2: The method for manufacturing the lithium-ion battery was the same as the method described in "II. Preparation of Lithium-ion Battery". Step 3: Obtained SiC x O y The material did not contain aluminum, and the powder had a gram capacity of 1510 mAh / g. The lithium-ion battery retained 87% of its capacity after 400 cycles, and its expansion rate was 11%.

[0073] Measurement method SEM measurement: (1) Preparation of samples for anode ion polishing (CP, Cross Section Polisher): The anode active material powder was fixed to the sample stage, and then treated with argon ion polishing (parameters: acceleration voltage 8KV, polishing for 4 hours per sample) to obtain anode active material CP samples. (2) After the preparation of the negative electrode active material CP sample was completed, SEM images of the negative electrode active material CP sample were taken using a scanning electron microscope (Philips XL-30 field emission scanning electron microscope) under conditions of 10 kV and 10 mA. The thickness of the Al2O3 layer was then measured using a scribe line.

[0074] Measurement of carbon content: Under oxygen-rich conditions, the sample was heated to a high temperature in a high-frequency furnace and burned, oxidizing carbon to carbon dioxide and sulfur to sulfur dioxide. The resulting gases were processed and entered the corresponding absorption cell, where they absorbed the corresponding infrared radiation and were converted into a corresponding signal by a detector. This signal was sampled by a computer, linearity corrected, and converted into numerical values ​​proportional to the concentrations of carbon dioxide and sulfur dioxide. After accumulating all the values ​​from the analysis process, the computer divided this accumulated value by the weight, multiplied by a calibration coefficient, and subtracted a blank to obtain the percentage of carbon and sulfur in the sample. The sample was measured using a high-frequency infrared sulfur-carbon analyzer (HCS-140, manufactured by Shanghai Dekai Instrument Co., Ltd.).

[0075] Measurement of silicon and aluminum content: A fixed amount of sample was weighed, a fixed amount of concentrated nitric acid was added, and the sample was decomposed using microwaves to obtain a solution. The obtained solution and filter cake were then washed multiple times to a fixed volume, and the plasma intensity of the elements in the solution was measured using ICP-OES. Based on the measured standard curves of the elements, the element content in the solution was calculated, thereby determining the amount of each element contained in the material.

[0076] Powder electrical conductivity: A resistance meter (ST-2255A, manufactured by Suzhou Jingge Electronic Co., Ltd.) was used. 5g of powder sample was taken and pressed to 5000kg ± 2kg using an electronic press, and this pressure was maintained for 15s to 25s. The sample was placed between the electrodes of the resistance meter, with the sample height h (cm), voltage across the terminals U, current I, resistance R (kΩ), and the area of ​​the pressed powder piece being 3.14cm². 2 The electronic conductivity (S / cm) of the powder was calculated using the formula δ = h / (3.14 × R) / 1000.

[0077] Measurement of specific surface area: After measuring the amount of gas adsorbed onto the solid surface at constant temperature and different relative pressures, the amount of adsorbed gas in the sample monolayer was determined using the Brownauer-Emmett-Teller adsorption theory and its formula (BET formula), and the specific surface area of ​​the solid was calculated.

[0078] Particle size distribution measurement: Approximately 0.02 g of powder sample was added to a clean 50 ml beaker, approximately 20 ml of deionized water was added, and a few drops of 1% surfactant were added to completely disperse the powder in the water. The mixture was then ultrasonically treated in a 120 W ultrasonic cleaner for 5 minutes, and the particle size distribution was measured using a MasterSizer 2000.

[0079] Measurement of the gram volume of the negative electrode active material: Under a dry argon atmosphere, propylene carbonate (PC), ethylene carbonate (EC), and diethyl carbonate (DEC) (weight ratio approximately 1:1:1) were mixed to obtain a solvent. LiPF6 was added to this solvent so that its content was approximately 12%, and the mixture was homogeneously mixed. Then, approximately 7.5% fluoroethylene carbonate (FEC) was added and homogeneously mixed to obtain the electrolyte.

[0080] The negative electrode active material, conductive carbon black, and the binder PAA (modified polyacrylic acid, PAA) were placed in deionized water in a weight ratio of approximately 80:10:10, stirred to form a slurry, and a coating layer approximately 100 μm thick was formed using a doctor blade. The mixture was placed in a vacuum drying box and dried at approximately 85°C for approximately 12 hours. Under a drying atmosphere, the mixture was cut into circular pieces approximately 1 cm in diameter using a punching machine. In a glove box, a lithium metal piece was selected as the counter electrode and the ceglard composite film as the separator. The electrolyte was then added, and the assembly was completed into a button cell. Charge and discharge measurements were performed on the battery using the LAND series battery test system.

[0081] Specifically, assembled button cells were taken, a normal open-circuit voltage (OCV) was ensured, and each group contained at least four replicated samples. The voltage window of the button cells was set to 0V to 2.5V. The cells were left standing at 25°C for 1 hour, and then discharged with three small currents of 0.05C / 50μA / 20μA to achieve SEI (Solid Electrolyte Interface Film) formation and record the lithium storage capacity. Subsequently, the cells were charged with a current of 0.1C until the voltage reached 2.5V, and the lithium release capacity, which is the gram capacity of the negative electrode active material, was recorded.

[0082] Cycle Measurement: At a measurement temperature of 25°C, the battery was charged to 4.45V with a constant current of 0.5C, then charged to 0.025C with a constant voltage, left to stand for 5 minutes, and then discharged to 3.0V at 0.5C. The capacity obtained in this step was defined as the initial capacity. Then, cycle measurements were performed with 0.5C charge / 0.5C discharge, and the ratio of the capacity after each cycle to the initial capacity was calculated to obtain a capacity decay curve. Here, the capacity retention rate after the nth cycle was = discharge capacity after the nth cycle / initial capacity × 100%.

[0083] Measurement of the expansion rate of a lithium-ion battery during full charge: At a measurement temperature of 25°C, the battery was charged to 4.45 V at a constant current of 0.5 C, then charged to 0.025 C at a constant voltage, allowed to stand for 5 minutes, and then discharged to 3.0 V at 0.5 C. Using a spiral micrometer, the thickness of the lithium-ion battery when it was charged to the initial half was measured and designated as h0. After cycling up to 400 times and when the lithium-ion battery was in a fully charged state, the thickness of the lithium-ion battery at this time was measured using a spiral micrometer and designated as h. The expansion rate of the lithium-ion battery was (h - h_0) / h_0 × 100%.

[0084] Measurement results Table 1 shows the influence of the thickness of the alumina layer on the characteristics of the negative electrode active material and the lithium-ion battery containing the negative electrode active material.

[0085] SiC of Comparative Example 1 x O y Materials of SiC in Examples 1 to 5 and the SiC of Comparative Example 1 x O y The @Al2O3 material had a firing temperature of 600°C and a firing time of 3 hours during the preparation process.

[0086] SiC of Comparative Example 1 x O y Materials of SiC in Examples 1 to 5 and the SiC of Comparative Example 1 x O y The @Al2O3 material had x = 0.015 and y = 0.95. SiC x O y All had a Dv50 of 5.7 μm, a ratio of Dn10 / Dv50 of 0.49, and an I2 / I1 of 0.78.

[0087] SiC of Comparative Example 1 and Examples 1 to 5 x O y had BET values of 1.78 m 2 / g, 1.78 m 2 / g, 1.46 m 2 / g, 1.98 m 2 / g, 2.02 m 2 / g, 2.58 m 2It was / g.

[0088] [Table 1]

[0089] The following can be seen from the data in Table 1. When the thickness of the Al2O3 layer is reduced, the Al content decreases, the ionic conductivity of the interface improves, and SiC x O y @Al2O3 material slightly increases gram capacity. However, as the Al2O3 layer becomes thinner, the resistance effect to HF corrosion weakens, resulting in a decrease in lithium-ion battery capacity retention and an increase in expansion rate. As the thickness of the Al2O3 layer increases, the Al content increases, worsening the ionic conductivity of the interface, and SiC x O y The gram capacity of the Al2O3 material decreases. If the Al2O3 layer is too thick, the amount of H2O produced by the reaction of Al2O3 and HF increases, which accelerates the decomposition of the electrolyte, generates more HF, prevents effective protection of the interface, and further reduces the capacity retention rate of the lithium-ion battery while increasing the expansion rate.

[0090] Table 2 shows the effect of the firing temperature and firing time in step 6 of the negative electrode active material preparation method on the properties of the obtained negative electrode active material and the lithium-ion battery containing said negative electrode active material.

[0091] SiC of Examples 6 to 10 x O y The Al2O3 material had an alumina layer thickness of 1 nm, with x = 0.015 and y = 0.95. x O y In all cases, Dv50 was 5.7 μm, the Dn10 / Dv50 ratio was 0.49, I2 / I1 was 0.78, and BET was 1.78 m. 2 It was / g.

[0092] [Table 2]

[0093] The following can be seen from the data in Table 2. When the firing temperature decreases, the bonding ability between Al and O weakens, and the stability of Al2O3 on the surface deteriorates. As a result, the protective effect of Al2O3 on the interface deteriorates, and the capacity retention rate of the lithium-ion battery decreases while the expansion rate increases. When the firing temperature increases, the bonding ability between Si and O strengthens, and crystallization occurs. As a result, the stress distribution during the cycle process becomes non-uniform, creating more new interfaces. Furthermore, the capacity retention rate of the lithium-ion battery decreases while the expansion rate increases.

[0094] If the firing time is too short, the bond strength between Al and O will be insufficient, resulting in poor Al2O3 stability on the surface. This leads to a reduced protective effect of Al2O3 on the interface, a decrease in the capacity retention rate of the lithium-ion battery, and an increase in the expansion rate. If the firing time is too long, the silicate phase increases, weakening the Si-Si bond strength and strengthening the Si-O bond strength, and furthermore, SiC x O y As a result of the deterioration in the structural stability of the Al2O3 material, the capacity retention rate of lithium-ion batteries decreases and the expansion rate increases.

[0095] Table 3 shows the influence of the x and y values ​​in the negative electrode active material on the properties of the negative electrode active material and the lithium-ion battery containing that negative electrode active material.

[0096] SiC of Examples 11-12 x O y The Al2O3 material was prepared at a firing temperature of 600°C for a firing time of 3 hours.

[0097] SiC of Examples 11-12 x O y The Al2O3 material had an alumina layer thickness of 1 nm. x O yIn all cases, Dv50 was 5.7 μm, the Dn10 / Dv50 ratio was 0.49, I2 / I1 was 0.78, and BET was 1.78 m. 2 It was / g.

[0098] [Table 3]

[0099] The following can be seen from the data in Table 3: As the x value increases, SiC x O y @In Al2O3 materials, the carbon content increases and the active silicon content decreases, so SiC x O y As the gram capacity of the Al2O3 material decreases, the cycle capacity retention rate of the lithium-ion battery decreases and the expansion rate increases when the same capacity is designed. As the x value decreases, SiC x O y @In Al2O3 materials, the carbon content is reduced and the active silicon content is increased, so SiC x O y While the gram capacity of Al2O3 material is increased, its structural stability deteriorates, resulting in a decrease in the cycle capacity retention rate and an increase in the expansion rate of lithium-ion batteries when designed for the same capacity.

[0100] While several exemplary embodiments of the present invention have been disclosed and described, the present invention is not limited to the disclosed embodiments. Rather, those skilled in the art should recognize that various modifications and changes can be made to the described embodiments without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. It is a negative electrode active material, The negative electrode active material comprises carbon-silicon-oxygen particles and an alumina layer located on the surface of the carbon-silicon-oxygen particles. The carbon silicon oxygen particles are SiC ｘ O ｙ This is shown that x and y satisfy 0 < x < 0.04 and 0.8 < y ≤ 0.

98. If the silicon content of the negative electrode active material is a%, the carbon content is b%, and the aluminum content is c%, then a, b, and c satisfy 0.001 ≤ c / a ≤ 0.003 and 0.008 ≤ c / b ≤ 0.

13. The carbon-silicon-oxygen particles are a negative electrode active material in which, in the X-ray diffraction pattern, the highest intensity value when 2θ is in the range of 28.0° to 29.0° is I2, and the highest intensity value when 2θ is in the range of 20.5° to 21.5° is I1, such that I2 and I1 satisfy 0 < I2 / I1 ≤ 1.

2. The negative electrode active material according to claim 1, wherein x and y satisfy 0.01 ≤ x ≤ 0.035 and 0.85 ≤ y ≤ 0.

98.

3. The negative electrode active material according to claim 1, wherein the thickness of the alumina layer is 0.5 nm to 10 nm.

4. The aforementioned negative electrode active material is (a) When the silicon element content is a% relative to the mass of the negative electrode active material, a satisfies 45 ≤ a ≤ 70. (b) When the carbon content is b% relative to the mass of the negative electrode active material, b satisfies 0.9 ≤ b ≤ 11, and (c) When the content of the aluminum element is c% relative to the mass of the negative electrode active material, c satisfies 0.04 ≤ c ≤ 1.

0. The negative electrode active material according to claim 1, satisfying at least one of the following conditions.

5. The aforementioned negative electrode active material is (d) The Dv50 range of the silicon-carbon oxygen particles is 2.5 μm to 10 μm. (e) The particle size distribution of the carbon-silicon-oxygen particles satisfies 0.3 ≤ Dn10 / Dv50 ≤ 0.

6. (g) The specific surface area of ​​the carbon-silicon-oxygen particles is 1 m² ２ / g to 50m ２ The fact that it is / g, and (h) The powder electrical conductivity of the negative electrode active material shall be 2.0 S / cm to 30 S / cm. The negative electrode active material according to claim 1, satisfying at least one of the following conditions.

6. A method for preparing a negative electrode active material according to claim 1, The above preparation method comprises the steps of: depositing a silicon-carbon-oxygen material and an aluminum source to obtain a reaction product; and calcining the reaction product at a calcination temperature of 300°C to 800°C and / or for a calcination time of 1 to 5 hours, wherein the method is for preparing a negative electrode active material.

7. An electrochemical apparatus, An electrochemical apparatus comprising a negative electrode, wherein the negative electrode comprises a negative electrode active material according to any one of claims 1 to 5.

8. The electrochemical apparatus according to claim 7, wherein the sheet resistance of the negative electrode is 0.2 Ω to 1 Ω.

9. An electronic apparatus comprising the electrochemical apparatus described in claim 7 or 8.

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