Carbonaceous material, method for producing the same, secondary battery and power consumption device including the same

Abstract

The present application provides a carbonaceous material, a method for manufacturing the same, a secondary battery including the same, and a power consumption device. When an adsorption test is performed using water vapor under constant temperature and humidity conditions of 25°C and 100% RH and then left standing for 100 h, if the adsorbed mass of water vapor is A and the initial mass of the carbonaceous material is B, then 0.13 ≦ A / B ≦ 0.50. The present application can simultaneously improve the capacity and the initial Coulomb efficiency of the carbonaceous material.

Description

Technical Field

[0001] This application belongs to the field of battery technology, and specifically relates to a carbonaceous material, a method for manufacturing the same, a secondary battery including the same, and a power consumption device.

Background Art

[0002] In recent years, secondary batteries have been widely used in many fields such as energy storage power systems such as hydraulic, thermal, wind, and solar power plants, and electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. With the application and popularization of secondary batteries, their energy density, service life, and rate performance have attracted increasing attention. Graphite is the most commonly used negative electrode active material in secondary batteries, but its theoretical gram capacity (capacity per gram) is only 372 mAh / g, and the room for improving energy density is very limited. At the same time, the interlayer distance of graphite is small, and the improvement of rate performance is also limited. Hard carbon, as a new negative electrode active material, can realize the rapid insertion and desorption of active ions during the charge and discharge process of secondary batteries, so the development prospect is very broad. However, the capacity and initial Coulomb efficiency of hard carbon are low, and there are limitations in improving the energy density, service life, and rate performance of secondary batteries.

Summary of the Invention

[0003] An object of this application is to provide a carbonaceous material, a method for manufacturing the same, a secondary battery including the same, and a power consumption device that can simultaneously improve the capacity and initial Coulomb efficiency of the carbonaceous material.

[0004] A first aspect of this application provides a carbonaceous material, which, under the constant temperature and humidity conditions of 25°C and 100% RH, is subjected to an adsorption test using water vapor and left standing for 100 h. After that, when the adsorbed mass of water vapor is A and the initial mass of the carbonaceous material is B, 0.13 ≤ A / B ≤ 0.50.

[0005] The inventors have found through research that when A / B is between 0.13 and 0.50, the carbonaceous material has high structural stability and many active ion storage spaces, and this part of the space is also advantageous for the reversible desorption and insertion of active ions. As a result, the carbonaceous material of the present application can achieve both high capacity and initial Coulomb efficiency, and can simultaneously endow the secondary battery with high energy density, long service life and good rate performance.

[0006] In any embodiment of the present application, 0.15 ≤ A / B ≤ 0.50, and optionally, 0.30 ≤ A / B ≤ 0.496. This is advantageous for further improving the capacity and initial Coulomb efficiency of the carbonaceous material.

[0007] In any embodiment of the present application, the true density ρ of the carbonaceous material is 1.0 g / cm 3 -1.6 g / cm 3 and optionally 1.05 g / cm 3 -1.45 g / cm 3 When the true density of the carbonaceous material further satisfies the above specific range, it contributes to further improving the gram capacity and initial Coulomb efficiency of the carbonaceous material.

[0008] In any embodiment of the present application, the carbonaceous material includes a plurality of nanoporous structures, and optionally, the carbonaceous material includes a plurality of pore structures with a pore diameter of 10 nm or less.

[0009] In any embodiment of the present application, in the Raman spectrum of the carbonaceous material, I d / I g is 1.0 - 1.3, and optionally 1.05 - 1.15. I d represents the intensity of the d peak within the range where the Raman shift is 1350 ± 50 cm -1 , and I g represents the intensity of the Raman shift within the range where the Raman shift is 1580 ± 50 cm -1It shows the intensity of the g peak within the range. In this case, since the degree of order of the structure of the carbonaceous material is appropriate, the carbonaceous material has a higher capacity, a higher initial Coulomb efficiency, and good rate performance.

[0010] In any embodiment of the present application, the interlayer distance of the (002) crystal plane of the carbonaceous material is ≧ 0.37 nm, and optionally 0.37 nm - 0.42 nm.

[0011] In any embodiment of the present application, in the X-ray diffraction spectrum of the carbonaceous material, the 2θ value corresponding to the peak of the (002) crystal plane is 22° - 24°.

[0012] In any embodiment of the present application, the volume particle size Dv50 of the carbonaceous material is 3 μm - 7 μm, and optionally 4 μm - 6 μm.

[0013] In any embodiment of the present application, the volume particle size Dv90 of the carbonaceous material is 8 μm - 15 μm, and optionally 9 μm - 12 μm.

[0014] When the volume particle size Dv50 and / or Dv90 of the carbonaceous material is in an appropriate range, it is beneficial to improve the active ion and electron transport performance, so the rate performance of the secondary battery can be further improved.

[0015] In any embodiment of the present application, the specific surface area of the carbonaceous material is 0.1 m 2 / g - 10 m 2 / g, and optionally 1 m 2 / g - 5 m 2 / g. When the specific surface area of the carbonaceous material is within an appropriate range, the carbonaceous material can have a higher capacity and an initial Coulomb efficiency at the same time, and can also have better rate performance.

[0016] In any embodiment of the present application, the powder compression density of the carbonaceous material under a 50000 N acting force is 0.90 g / cm 3 -1.05 g / cm 3and is optionally 0.93 g / cm 3 -1.02 g / cm 3 When the bulk density of the carbonaceous material is within an appropriate range, the compression density of the negative electrode sheet can be improved, and further the energy density of the secondary battery can be improved.

[0017] In any embodiment of the present application, the tap density of the carbonaceous material is 0.80 g / cm 3 -0.95 g / cm 3 and is optionally 0.85 g / cm 3 -0.90 g / cm 3 When the tap density of the carbonaceous material is within an appropriate range, the compression density of the negative electrode sheet can be improved, and further the energy density of the secondary battery can be improved.

[0018] The second aspect of the present application is a raw material providing step S10, which is a step in which the raw material is an organic carbon source, a crushing treatment step S20, which is a step of crushing the raw material to a desired particle size, a washing and impurity removal treatment step S30, which performs a washing and impurity removal treatment on the crushed raw material obtained in S20, and the process of the washing and impurity removal treatment includes at least a washing step with an acidic solution and a washing step with an alkaline solution, a carbonization treatment step S40, which puts the washed and impurity-removed raw material obtained in S30 into a kiln furnace, introduces a protective gas containing hydrogen gas, controls the pressure in the furnace chamber to ≤ -2 kPa, then raises the temperature to a target temperature T1 at a rate of ≤ 1 °C / min, holds the temperature at the target temperature T1 for a target time t1, and after completion, obtains a carbonaceous material, Here, the carbonaceous material is subjected to an adsorption test using water vapor under constant temperature and humidity conditions of 25 °C and 100% RH, and after standing for 100 h, when the adsorbed mass of water vapor is A and the initial mass of the carbonaceous material is B, 0.13 ≤ A / B ≤ 0.50, and a method for producing a carbonaceous material is provided.

[0019] The carbonaceous material obtained by the manufacturing method according to the present application can achieve both high capacity and initial Coulomb efficiency. As a result, the secondary battery can simultaneously have a high energy density, a long service life, and good rate performance.

[0020] In any embodiment of the present application, in S20, the crushing includes ball mill crushing or jet mill crushing.

[0021] In any embodiment of the present application, in S30, the process of the washing and impurity removal treatment sequentially includes steps of washing with an acidic solution, water washing, washing with an alkaline solution, water washing, and drying, or in S30, the process of the washing and impurity removal treatment sequentially includes steps of washing with an alkaline solution, water washing, washing with an acidic solution, water washing, and drying.

[0022] In any embodiment of the present application, the H + concentration of the acidic solution is 0.1 mol / L - 6 mol / L, and optionally 1 mol / L - 6 mol / L.

[0023] In any embodiment of the present application, the washing temperature of the acidic solution is 10°C - 95°C, and optionally 30°C - 95°C.

[0024] In any embodiment of the present application, the washing time of the acidic solution is 1 h - 24 h, and optionally 10 h - 24 h.

[0025] In any embodiment of the present application, the solute of the acidic solution includes one or more of hydrochloric acid, nitric acid, sulfuric acid, and perchloric acid, and the solvent includes water.

[0026] Adjusting one or more of the H + concentration, washing temperature, washing time, type of solute, etc. of the acidic solution within the above range is advantageous for achieving sufficient washing and more preferably removing metal impurities.

[0027] In any embodiment of the present application, the OH of the alkaline solution - concentration is 0.1 mol / L - 6 mol / L, and optionally 1 mol / L - 6 mol / L.

[0028] In any embodiment of the present application, the washing temperature of the alkaline solution is 10°C - 95°C, and optionally 30°C - 95°C.

[0029] In any embodiment of the present application, the washing time of the alkaline solution is 1 h - 24 h, and optionally 10 h - 24 h.

[0030] In any embodiment of the present application, the solute of the alkaline solution includes NaOH, KOH, or a combination thereof, and the solvent includes water.

[0031] OH of the alkaline solution - By adjusting one or more of the concentration, washing temperature, washing time, type of solute, etc. within the above ranges, it is advantageous for achieving sufficient washing.

[0032] In any embodiment of the present application, in S40, the temperature T1 is 1000°C - 1600°C, and optionally 1150°C - 1500°C. When the temperature T1 is within the above range, the closed pore effect of the carbonaceous material is good, the size of the pore structure is small, and there is a large storage space for active ions. Therefore, the capacity of the carbonaceous material is high. At the same time, the proportion of the infiltration region of the electrolyte inside the carbonaceous material is low, and the consumption of active ions due to the formation of the SEI film is low. Therefore, the initial irreversible capacity loss of the carbonaceous material is low, and the initial Coulomb efficiency is high.

[0033] In any embodiment of the present application, in S40, the time t1 is 1 h or more (≧1 h), and optionally 10 h - 24 h. When the heat preservation time t1 is within the above range, the content of impurity atoms in the carbonaceous material can be effectively reduced, and the carbonaceous material can be made to have a high initial Coulomb efficiency.

[0034] In any embodiment of the present application, in S40, the rate of temperature increase is 0.05 °C / min to 1 °C / min, and optionally 0.1 °C / min to 1 °C / min. Thereby, the production efficiency can be improved and the waste of energy can be reduced.

[0035] In any embodiment of the present application, in S40, the protective gas includes a mixed gas of hydrogen gas and an inert gas, and the volume concentration of the hydrogen gas is greater than 0 and less than or equal to 5%, and optionally 1% - 5%. The volume concentration of hydrogen gas is mainly less than or equal to 5% (≤5%) from the perspective of safety.

[0036] In any embodiment of the present application, in S40, the pressure in the furnace chamber is -5 kPa to -2 kPa, and optionally -5 kPa to -3 kPa. Thereby, it is advantageous for ensuring safe production.

[0037] In any embodiment of the present application, in S10, the organic carbon source includes one or more of biomass materials and thermoplastic resin materials.

[0038] In any embodiment of the present application, the biomass material includes one or more of energy crops and biomass waste.

[0039] In any embodiment of the present application, the thermoplastic resin material includes one or more of phenolic resin, acrylic resin, polyvinyl chloride, polycarbonate, epoxy resin, polyoxymethylene, coumarone resin, and petroleum resin.

[0040] A third aspect of the present application provides a secondary battery including a negative electrode sheet containing the carbonaceous material of the first aspect of the present application or the carbonaceous material manufactured by the method of the second aspect of the present application.

[0041] A fourth aspect of the present application provides a power consumption device including the secondary battery of the third aspect of the present application.

[0042] The carbonaceous material according to the present application can achieve both high capacity and initial Coulomb efficiency, and endow the secondary battery with high energy density, long service life and good rate performance at the same time. Since the power consumption device of the present application includes the secondary battery according to the present application, it has at least the same advantages as the secondary battery.

Brief Description of the Drawings

[0043] To more clearly explain the technical solutions of the embodiments of the present application, the drawings that need to be used in the embodiments of the present application will be briefly described below. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can also obtain other drawings based on the drawings without creative efforts. The drawings are not necessarily drawn to actual scale.

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Embodiments for Carrying Out the Invention

[0044] Hereinafter, with reference to the drawings as appropriate, embodiments specifically disclosing the carbonaceous material of the present application, its manufacturing method, and secondary batteries and power consumption devices including the same will be described in detail. However, detailed descriptions that are not necessary may be omitted. For example, detailed descriptions of known matters or redundant descriptions of substantially the same configurations may be omitted. This is to avoid the following description from being unnecessary and redundant and to facilitate the understanding of those skilled in the art. Note that the attached drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0045] In the present application, the "range" disclosed is defined in the form of a lower limit and an upper limit. A predetermined range is defined by selecting one lower limit and one upper limit, and the selected lower limit and upper limit limit the boundaries of a special range. The range thus limited may be a range including the end values or not including the end values, and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, when ranges of 60-120 and 80-110 are given for a specific parameter, it is understood that ranges of 60-110 and 80-120 are also expected. Also, when the minimum range values 1 and 2 and the maximum range values 3, 4, and 5 are given, ranges of 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5 may all be expected. In the present application, unless otherwise explained, the numerical range "a-b" is represented by an abbreviation of any combination of real numbers between a and b, and both a and b are real numbers. For example, the numerical range "0-5" indicates listing all real numbers between "0-5" in this specification, and "0-5" is an abbreviation of the combination of these numerical values. Also, when a certain parameter is expressed as an integer of 2 or more (≧2), it corresponds to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0046] Unless otherwise specified, all embodiments and selectable embodiments of the present application can be combined with each other to form a new technical solution. Also, such a technical solution should be regarded as being included in the disclosure content of the present application.

[0047] Unless otherwise specified, all technical features of this application and selectable technical features can be combined with each other to form a new technical solution. Moreover, such a technical solution should be regarded as being included in the disclosure content of this application.

[0048] Unless otherwise specified, all steps of this application may be performed in sequence or randomly, but it is preferred to be performed in sequence. For example, the fact that the above method includes steps (a) and (b) means that the above method may include steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, when it is mentioned that the above method may further include step (c), it means that step (c) may be added to the above method in any order. For example, the above method may include steps (a), (b) and (c), may include steps (a), (c) and (b), may include steps (c), (a) and (b), etc.

[0049] Unless otherwise specified, the terms "comprising" and "including" described in this application are meant to be open-ended and may also be closed-ended. For example, the above "comprising" and the above "including" can represent further "comprising" or "including" other components not listed, or "comprising" or "including" only the components listed.

[0050] Unless otherwise specified, in this application, the term "or" is inclusive. For example, the phrase "A or B" represents "A, B, or both A and B". More specifically, any of the following conditions is satisfied. A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), or both A and B are true (or exist).

[0051] Unless otherwise specified, the terms used in this application have the meanings known to those skilled in the art and are commonly understood.

[0052] Unless otherwise specified, the numerical values of each parameter mentioned in this application can be measured by various test methods commonly used in this field. For example, they can be measured according to the test methods provided in this application.

[0053] Unless otherwise specified, in this application, the term "active ion" refers to an ion that can be inserted and desorbed reciprocally between the positive electrode and the negative electrode of a secondary battery, including but not limited to lithium ions, sodium ions, etc.

[0054] In this application, the terms "a plurality" and "a plurality of types" refer to two or more.

[0055] According to the definition of the International Union of Pure and Applied Chemistry (IUPAC), micropores refer to pores with a pore diameter < 2 nm, mesopores refer to pores with a pore diameter of 2 nm - 50 nm, and macropores refer to pores with a pore diameter > 50 nm.

[0056] In the specification of this application, whenever the term "micropore" is mentioned, it refers to pores with a pore diameter < 2 nm; whenever the term "mesopore" is mentioned, it refers to pores with a pore diameter of 2 nm - 50 nm; and whenever the term "macropore" is mentioned, it refers to pores with a pore diameter > 50 nm.

[0057] In the specification of this application, the term "small mesopore" refers to pores with a pore diameter of 2 nm - 10 nm, and the term "large mesopore" refers to pores with a pore diameter greater than 10 nm and less than or equal to 50 nm.

[0058] With the application and popularization of secondary batteries, their energy density, service life, and rate performance have attracted increasing attention. The performance of the negative electrode active material determines to a certain extent the energy density, service life, and safety of secondary batteries. Graphite (including natural graphite and artificial graphite) is the most commonly used negative electrode active material in secondary batteries, but its theoretical gram capacity is only 372 mAh / g, and there is very limited room for improving the energy density. At the same time, the interlayer distance of graphite is small, and the improvement of the rate performance is also limited, making it unable to meet the actual needs of secondary batteries with high rate performance.

[0059] Compared with graphite, hard carbon has a larger interlayer distance, which is beneficial to the rapid insertion and desorption of active ions. Therefore, secondary batteries can be given excellent low-temperature performance, output performance, and safety performance. In particular, in the field of power batteries, hard carbon has unique advantages. However, most of the currently commercialized hard carbon belongs to the low-capacity type, with low capacity and first Coulomb efficiency. For example, the capacity is usually 200 mAh / g - 300 mAh / g, and the first Coulomb efficiency is usually less than 85%, which severely limits its actual application.

[0060] Therefore, simultaneously improving the capacity and first Coulomb efficiency of hard carbon is a technical problem that needs to be solved currently.

[0061] In view of this, the first aspect of the embodiments of the present application provides a carbonaceous material that can achieve both high capacity and first Coulomb efficiency, and simultaneously endow secondary batteries with high energy density, long service life, and good rate performance. Carbonaceous material

[0062] The carbonaceous material according to the present application, under the constant temperature and humidity conditions of 25°C and 100% RH, after performing an adsorption test using water vapor and standing for 100 h, when the adsorbed mass of water vapor is A and the initial mass of the carbonaceous material is B, 0.13 ≤ A / B ≤ 0.50.

[0063] The adsorption test is carried out by uniformly placing the carbonaceous material with mass B in a watch glass with a diameter of 10 cm in a thermostatic and humidified chamber at 25°C and 100% RH, ensuring that the deposition thickness of the carbonaceous material is 0.2 cm or less (≦0.2 cm), allowing it to stand for 100 h, and then weighing the increased mass of the carbonaceous material to obtain the adsorbed mass A of water vapor.

[0064] RH (Relative Humidity) indicates relative humidity and refers to the percentage of the partial pressure of water vapor in the air with respect to the saturated vapor pressure of water at the same temperature.

[0065] Compared with currently commercialized hard carbon, the carbonaceous material according to the present application can achieve both high capacity and initial Coulomb efficiency. Although the mechanism is not clear, the inventors believe that the possible reason is that the carbonaceous material according to the present application has a unique pore structure, which can facilitate the insertion, storage, and desorption of active ions. Furthermore, the carbonaceous material according to the present application can achieve both high capacity and initial Coulomb efficiency.

[0066] During the research process, the inventors of the present application found that under the thermostatic and humidified conditions of 25°C and 100% RH, the mass A / B of water vapor adsorbed by the carbonaceous material per unit mass within 100 h can reflect the content of the space suitable for the storage, reversible desorption, and insertion of active ions in the carbonaceous material.

[0067] If A / B is less than 0.13, the adsorbed mass of water vapor by the carbonaceous material decreases, and there is less space suitable for the storage, reversible desorption, and insertion of active ions contained inside the carbonaceous material. Therefore, it is considered that the capacity and initial Coulomb efficiency of the carbonaceous material are low.

[0068] When A / B exceeds 0.50, the adsorption mass of the carbonaceous material to water vapor increases. However, during the research process, the inventors found that at this time, a large amount of water vapor is adsorbed into the interlayer structure of the carbonaceous material, but this part of the interlayer structure cannot effectively store active ions. Also, due to the overly high closed-pore effect of the carbonaceous material, there is a possibility that active ions are less likely to be inserted into the pore structure of the carbonaceous material. Therefore, when A / B is greater than 0.50, the space suitable for the storage and reversible desorption and insertion of active ions contained inside the carbonaceous material also decreases, and both the capacity and the initial Coulomb efficiency of the carbonaceous material are low.

[0069] During the research process, the inventors found that when A / B is between 0.13 and 0.50, the carbonaceous material has high structural stability, has many active ion storage spaces, and this part of the space is also advantageous for the reversible desorption and insertion of active ions. As a result, the carbonaceous material of this application can achieve both high capacity and initial Coulomb efficiency, and can simultaneously endow the secondary battery with high energy density, long service life, and good rate performance. For example, A / B may be in the range consisting of any numerical values such as 0.14, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50 or more. In some embodiments, optionally, 0.15≤A / B≤0.50, 0.20≤A / B≤0.50, 0.25≤A / B≤0.498, 0.30≤A / B≤0.496, 0.35≤A / B≤0.496, 0.40≤A / B≤0.496. This is advantageous for further improving the capacity and initial Coulomb efficiency of the carbonaceous material.

[0070] In some embodiments, the carbonaceous material includes a plurality of nanopore structures. Optionally, the carbonaceous material includes a plurality of pore structures with a pore diameter of 10 nm or less. In some embodiments, the carbonaceous material may further include one or more pore structures with a pore diameter greater than 10 nm.

[0071] In further research, the inventors found that by adjusting the true density of the carbonaceous material within an appropriate range after ensuring that the parameter A / B of the carbonaceous material satisfies 0.13 ≦ A / B ≦ 0.50, the content of the space suitable for the storage, reversible desorption, and insertion of active ions in the carbonaceous material can be more accurately reflected.

[0072] During the true density test, the space into which the calibration liquid (e.g., n-butanol) can enter is less than the space actually possessed by the carbonaceous material, and these unentered spaces may store active ions. The parameter A / B can reflect the content of the space suitable for the storage, reversible desorption, and insertion of active ions in the carbonaceous material. However, the carbonaceous material further includes an interlayer structure in addition to the pore structure. The interlayer structure cannot effectively store active ions, and the calibration liquid does not enter the interlayer structure, while water vapor can be adsorbed and enter the interlayer structure. Thus, the space suitable for the storage, reversible desorption, and insertion of active ions reflected by the parameter A / B may include some spaces that cannot effectively store active ions. Therefore, by simultaneously adjusting the parameter A / B and the true density of the carbonaceous material within an appropriate range, the content of the space suitable for the storage, reversible desorption, and insertion of active ions in the carbonaceous material can be more accurately reflected.

[0073] In some embodiments, the true density ρ of the carbonaceous material is 1.0 g / cm 3 -1.6 g / cm 3 , for example, 1.0 g / cm 3 、1.05 g / cm 3 、1.1 g / cm 3 、1.15 g / cm 3 、1.2 g / cm 3 、1.25 g / cm 3 、1.3 g / cm 3 、1.35 g / cm 3 、1.4 g / cm 3 、1.45 g / cm 3 、1.5 g / cm 3 、1.55 g / cm 3Or it may be a range consisting of any of the above numerical values. Optionally, the true density ρ of the carbonaceous material is 1.05 g / cm 3 - 1.45 g / cm 3 、1.10 g / cm 3 - 1.40 g / cm 3 . The inventors have found in further research that when the true density of the carbonaceous material further satisfies the above specific range, it contributes to further improvement in the gram capacity and initial Coulombic efficiency of the carbonaceous material.

[0074] Whether the true density of the carbonaceous material is too high or too low is disadvantageous for improving the gram capacity and initial Coulombic efficiency of the carbonaceous material. When the true density of the carbonaceous material is too low, the space into which the calibration liquid (for example, n-butanol) can enter decreases, and the closed pore effect of the carbonaceous material is too high, so it is difficult for active ions to be inserted into the pore structure. Also, it is considered that there are many interlayer structures that are not suitable for storing active ions contained in the carbonaceous material.

[0075] When the true density of the carbonaceous material is too large, the calibration liquid (for example, n-butanol) is likely to infiltrate into the inside of the carbonaceous material particles. At this time, the closed pore effect of the carbonaceous material deteriorates, and since there are abundant large mesopore structures and / or macropore structures, the micropore structures and / or small mesopore structures are likely to be exposed to the electrolyte, reducing the storage space for active ions, and it is considered that the gram capacity and initial Coulombic efficiency of the carbonaceous material decrease.

[0076] In the present application, the true density of the carbonaceous material has the meaning known in the art and can be measured by equipment and methods known in the art. For example, it can be measured using the Archimedes immersion volume replacement method, and n-butanol can be used as the calibration liquid. The test equipment can use a powder true density meter.

[0077] In some embodiments, the carbonaceous material may have a regular or irregular form. For example, the form of the carbonaceous material may be an irregular polygon.

[0078] In some embodiments, the content of C element in the carbonaceous material is 95 wt% or more (≧95 wt%), and optionally may be 95 wt% - 98 wt%.

[0079] In some embodiments, the content of O element in the carbonaceous material is 5 wt% or less (≦5 wt%), and optionally may be 1 wt% - 5 wt%. Oxygen impurity atoms cannot reversibly desorb active ions after binding to the active ions. Since the content of oxygen impurity atoms in the carbonaceous material according to the present application is low, irreversible consumption of active ions can be reduced.

[0080] In some embodiments, the content of H element in the carbonaceous material is 0.3 wt% or less (≦0.3 wt%), and optionally may be 0.1 wt% - 0.2 wt%.

[0081] In some embodiments, the content of N element in the carbonaceous material is 0.3 wt% or less (≦0.3 wt%), and optionally may be 0.01 wt% - 0.1 wt%.

[0082] In some embodiments, the total content of C, O, H and N elements in the carbonaceous material is 99 wt% or more (≧99 wt%), and optionally may be 99 wt% - 99.5 wt%.

[0083] In some embodiments, the content of S element in the carbonaceous material is 0.2 wt% or less (≦0.2 wt%), and optionally may be 0.01 wt% - 0.1 wt%.

[0084] In some embodiments, the content of Na element in the carbonaceous material is 0.014 wt% or less (≦0.014 wt%), and optionally may be 0.005 wt% or less (≦0.005 wt%).

[0085] In some embodiments, in the Raman spectrum of the carbonaceous material, I d / I g is 1.0 - 1.3, and I d represents the intensity of the d peak within the range of Raman shift of 1350 ± 50 cm -1 , and I g represents the intensity of the g peak within the range of Raman shift of 1580 ± 50 cm -1 . For example, I d / I g may be in the range consisting of 1.0, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3 or any numerical value greater than or equal to that. Optionally, I d / I g may be 1.05 - 1.15.

[0086] The Raman spectrum of the carbonaceous material can be measured using a Raman spectrometer. During the measurement, the intensities of the d peak and the g peak at 100 points are obtained, and the I d / I g is calculated. The maximum and minimum 30 I d / I g are removed, and the average value of the remaining 40 I d / I g is taken as the I d / I g of the carbonaceous material. The test equipment may be a Horiba LabRAM HR800 Raman spectrometer. The test conditions may be an excitation wavelength of 532 nm, a diffraction grating of 600 lines, an objective lens of 50x, an integration time of 10 s, a cumulative number of 3 times, and a surface scan.

[0087] The d peak is due to the lattice defects of carbon atoms, and the g peak is due to the in-plane vibration of sp2 carbon atoms. In the structure of the carbonaceous material, the d peak intensity is related to the number of defects in the carbonaceous material structure, and the g peak intensity is related to the number of graphite microcrystals in the carbonaceous material structure. Therefore, I d / I g can represent the degree of order of the carbonaceous material structure. The smaller I d / I g is, the higher the degree of order of the carbonaceous material structure, the higher the perfection of the carbon plane, and the increase in the initial Coulomb efficiency of the carbonaceous material, but the capacity decreases and the rate performance deteriorates. The carbonaceous material of the present application has I d / Ig Satisfies that it is 1.0 - 1.3. In this case, since the degree of order of the structure of the carbonaceous material is appropriate, the carbonaceous material has a higher capacity, a higher initial Coulomb efficiency, and good rate performance.

[0088] In some embodiments, the interlayer distance of the (002) crystal plane of the carbonaceous material is ≧ 0.37 nm, and optionally 0.37 nm - 0.42 nm.

[0089] In some embodiments, in the X-ray diffraction spectrum of the carbonaceous material, the 2θ value corresponding to the (002) crystal plane peak is 22° - 24°.

[0090] In the present application, the interlayer distance of the (002) crystal plane of the carbonaceous material can be measured using an X-ray diffractometer with reference to JIS K 0131-1996 and JB / T 4220-2011. The test equipment may be an X-ray diffractometer of Bruker D8 Discover.

[0091] In some embodiments, the volume particle size Dv50 of the carbonaceous material is 3 μm - 7 μm, and optionally 4 μm - 6 μm.

[0092] In some embodiments, the volume particle size Dv90 of the carbonaceous material is 8 μm - 15 μm, and optionally 9 μm - 12 μm.

[0093] In some embodiments, the carbonaceous material has a volume particle size Dv50 of 3 μm - 7 μm and a volume particle size Dv90 of 8 μm - 15 μm. Optionally, the volume particle size Dv50 of the carbonaceous material is 4 μm - 6 μm, and the volume particle size Dv90 is 9 μm - 12 μm.

[0094] When the volume particle size Dv50 and / or Dv90 of the carbonaceous material is in an appropriate range, it is beneficial for improving the active ion and electron transport performance, and thereby the rate performance of the secondary battery can be further improved.

[0095] In this application, the volume particle sizes Dv50 and Dv90 of the carbonaceous material have the meanings known in this field, indicating the particle sizes corresponding to when the cumulative volume distribution percentages of the material reach 50% and 90% respectively, and can be measured by devices and methods known in this field. For example, referring to the laser diffraction method for particle size distribution in GB / T 19077-2016, it can be conveniently measured using a laser particle size analyzer. The test device may be a Mastersizer 2000E type laser particle size analyzer of Malvern Instruments Limited, UK.

[0096] In some embodiments, the specific surface area of the carbonaceous material is 0.1 m 2 / g - 10 m 2 / g, and optionally 1 m 2 / g - 5 m 2 / g. When the specific surface area of the carbonaceous material is low, it reduces the surface activity of the carbonaceous material, decreases the consumption of active ions due to the formation of the SEI film, and thereby contributes to improving the initial Coulombic efficiency of the carbonaceous material and the secondary battery. When the specific surface area of the carbonaceous material is high, it contributes to accelerating the transport of active ions, and thereby improves the rate performance of the secondary battery. Therefore, when the specific surface area of the carbonaceous material is within an appropriate range, the carbonaceous material can simultaneously have a higher capacity and initial Coulombic efficiency, and can also have better rate performance. Also, when the specific surface area of the carbonaceous material is within an appropriate range, it can have a strong binding force with the binder, thereby improving the cohesion and adhesion of the negative electrode sheet, reducing the volume expansion during the cycling process of the negative electrode sheet, and enabling the secondary battery to have better cycle performance.

[0097] In this application, the specific surface area of the carbonaceous material has the meaning known in the art and can be measured by equipment and methods known in the art. For example, referring to GB / T 19587-2017, it can be tested by the nitrogen gas adsorption specific surface area analysis test method and calculated by the BET (Brunauer Emmett Teller) method. Here, the nitrogen gas adsorption specific surface area analysis test can be measured by an ASAP 3020 type surface area and pore size analyzer manufactured by Micromeritics, USA.

[0098] In some embodiments, the powder compression density of the carbonaceous material under a 50,000 N acting force is 0.90 g / cm 3 -1.05 g / cm 3 and optionally 0.93 g / cm 3 -1.02 g / cm 3 When the powder compression density of the carbonaceous material is within an appropriate range, the compression density of the negative electrode sheet can be improved, and further the energy density of the secondary battery can be improved.

[0099] In this application, the powder compression density of the carbonaceous material has the meaning known in the art and can be measured by equipment and methods known in the art. For example, referring to GB / T24533-2009, it can be measured by an electronic pressure tester (for example, UTM7305 type). As an exemplary measurement method, 1 g of carbonaceous material powder is weighed and placed in a mold with a bottom area of 1.327 cm 2 and pressurized up to 5000 kg (equivalent to 50,000 N), held under pressure for 30 s, then the pressure is released and held for 10 s, and then the powder compression density of the carbonaceous material under a 50,000 N acting force is recorded and calculated.

[0100] In some embodiments, the tap density of the carbonaceous material is 0.80 g / cm 3 -0.95 g / cm 3 and optionally 0.85 g / cm 3 -0.90 g / cm 3 When the tap density of the carbonaceous material is within an appropriate range, the compression density of the negative electrode sheet can be improved, and further the energy density of the secondary battery can be improved.

[0101] In the present application, the tapped density of the carbonaceous material has the meaning known in the art and can be measured by equipment and methods known in the art. For example, referring to GB / T 5162-2006, it can be measured using a powder tapped density tester. As the test equipment, Dandong Baite BT-301 can be used. Method for producing carbonaceous material

[0102] The second aspect of the embodiment of the present application provides a method for manufacturing a carbonaceous material, the method including a raw material providing step S10, in which the raw material is an organic carbon source; a crushing treatment step S20, in which the raw material is crushed to a desired particle size; a washing and impurity removal treatment step S30, in which the crushed raw material obtained in S20 is subjected to washing and impurity removal treatment, and the process of the washing and impurity removal treatment includes at least a washing step with an acidic solution and a washing step with an alkaline solution; and a carbonization treatment step S40, in which the washed and impurity-removed raw material obtained in S30 is put into a kiln furnace, a protective gas containing hydrogen gas is introduced, the pressure in the furnace chamber is controlled to be ≤ -2 kPa, and then the temperature is raised to a target temperature T1 at a rate of ≤ 1 °C / min, and heat preservation treatment is performed at the target temperature T1 for a target time t1, and after completion, a carbonaceous material is obtained. Here, when an adsorption test is performed on the carbonaceous material using water vapor under constant temperature and humidity conditions of 25 °C and 100% RH and left standing for 100 h, and the adsorbed mass of water vapor is A and the initial mass of the carbonaceous material is B, then 0.13 ≤ A / B ≤ 0.50.

[0103] The method for manufacturing a carbonaceous material according to the present application includes a crushing treatment step, a washing and impurity removal treatment step, and a carbonization treatment step.

[0104] Crushing can reduce the particle size of the raw material and contribute to obtaining a carbonaceous material of a desired size. In some embodiments, the volume median diameter Dv50 of the particles after crushing is 3 μm - 7 μm, and optionally 4 μm - 6 μm. In some embodiments, the volume median diameter Dv90 of the particles after crushing is 8 μm - 15 μm, and optionally 9 μm - 12 μm. In some embodiments, the volume median diameter Dv50 of the particles after crushing is 3 μm - 7 μm, and the volume median diameter Dv90 is 8 μm - 15 μm. Optionally, the volume median diameter Dv50 of the particles after crushing is 4 μm - 6 μm, and the volume median diameter Dv90 is 9 μm - 12 μm.

[0105] The washing and impurity removal treatment can remove inorganic impurities and water-soluble impurities in the raw material, thereby avoiding the reduction and aggregation of metal impurities into metal monomers in the subsequent carbonization process. In the aggregation process of metal monomers, the collapse of the carbon skeleton structure is caused, especially the collapse of the micropore structure and / or small mesopore structure, resulting in a decrease in the active ion storage space and capacity of the obtained carbonaceous material. At the same time, metal impurities have catalytic activity, and the decomposition of the carbon skeleton structure becomes more intense in the pyrolysis process, and the pore structure tends to form large mesopore structures and / or macropore structures with large sizes. As a result, the proportion of the infiltration region of the electrolyte inside the obtained carbonaceous material increases, the consumption of active ions due to the formation of the SEI film increases, the first irreversible capacity loss increases, and the first Coulombic efficiency decreases. The process of the washing and impurity removal treatment includes at least a washing step with an acidic solution and a washing step with an alkaline solution. The acidic solution is mainly used to remove metal impurities in the raw material, and the alkaline solution is mainly used to remove Si-containing impurities that cannot react with acids in the raw material, etc., thereby ensuring sufficient removal of impurities.

[0106] The crushing treatment step needs to be carried out before the washing and impurity removal treatment step. Thereby, when performing washing and impurity removal, as many surfaces of the particles as possible can be exposed so that the particles and the cleaning liquid can come into sufficient contact to enhance the impurity removal effect. If the crushing treatment step is carried out after the washing and impurity removal treatment step, there is a possibility that the cleaning liquid may not enter the bulk phase of the bulk raw material particles, and furthermore, impurities deeply wrapped in the bulk phase of the bulk raw material particles cannot be removed, resulting in a poor impurity removal effect. Further, in the subsequent carbonization treatment process, the metal impurities that have not been removed are reduced to elemental metals and aggregated. In the aggregation process of the elemental metal, it causes the collapse of the carbon skeleton structure, especially the collapse of the micropore structure and / or small mesopore structure, further causing a decrease in the active ion storage space and a decrease in the capacity of the obtained carbonaceous material. At the same time, the metal impurities have catalytic activity and cause the progress of the decomposition of the carbon skeleton structure in the pyrolysis process, and tend to form a large mesopore structure and / or macropore structure with a large pore size, whereby the ratio of the infiltration region of the electrolyte inside the obtained carbonaceous material increases, the consumption of active ions due to the formation of the SEI film increases, the first irreversible capacity loss increases, and the first Coulombic efficiency decreases.

[0107] The heating rate during carbonization treatment was set to 1 °C / min or less (≤1 °C / min). If the heating rate is too fast, the gaseous small-molecule substances released during the thermal decomposition process of the raw material cannot escape from the bulk phase of the particles to the surface and then be conducted to the furnace chamber and discharged by the protective gas in the furnace chamber. These gaseous small-molecule substances are bound in the bulk phase of the particles and are converted into carbon through thermal decomposition again, thereby blocking the pore structure, reducing the active ion storage space of the obtained carbonaceous material, and decreasing the capacity. Also, if the heating rate is too fast, the true density of the carbonaceous material of the same size increases, and the pore structure of the carbonaceous material is not smooth, increasing the difficulty of desorption of active ions and further decreasing the first Coulombic efficiency.

[0108] The protective gas during carbonization treatment contains hydrogen gas. Hydrogen gas has a reducing effect and can reduce the formation of oxygen-containing functional groups on the surface of the carbonaceous material. Therefore, it can ultimately reduce the defects of impurity atoms (such as oxygen impurity atoms) in the produced carbonaceous material and increase the initial Coulombic efficiency. When the protective gas does not contain hydrogen gas, some of the oxygen-containing functional groups on the surface of the carbonaceous material cannot be effectively reduced, resulting in too many oxygen impurity atoms in the finally produced carbonaceous material. After oxygen impurity atoms combine with active ions, they cannot reversibly desorb the active ions, causing a decrease in the initial Coulombic efficiency of the carbonaceous material. At the same time, many oxygen-containing functional groups remain on the surface of the carbonaceous material, and a hydrogen bonding effect is formed between these oxygen-containing functional groups and water molecules. Many water molecule clusters accumulate on the surface of the carbonaceous material, inhibiting the insertion of active ions, thereby reducing the gram capacity of the carbonaceous material.

[0109] During the research process, the inventors of the present application unexpectedly found that the furnace chamber pressure of the kiln affects the performance of the finally produced carbonaceous material. If the furnace chamber pressure is too high, the gaseous small molecule substances released during the thermal decomposition process of the raw material cannot leak out of the bulk phase of the particles in a timely manner. These gaseous small molecule substances are bound in the bulk phase of the particles and are converted into carbon through thermal decomposition again, thereby blocking the pore structure. As a result, the active ion storage space of the obtained carbonaceous material decreases and the capacity decreases. In addition, if the furnace chamber pressure is too high, the true density of the carbonaceous material of the same size increases, the pore structure of the carbonaceous material is not smooth, the difficulty of desorbing active ions increases, and the initial Coulombic efficiency further decreases.

[0110] Therefore, the carbonaceous material obtained by the manufacturing method according to the present application can achieve both high capacity and initial Coulombic efficiency, thereby enabling the secondary battery to simultaneously have high energy density, long service life, and good rate performance.

[0111] The manufacturing method of the second aspect of the embodiment of the present application can manufacture the carbonaceous material of any of the examples of the first aspect of the embodiment of the present application. The manufacturing method of the carbonaceous material according to the present application has a simple process and is suitable for mass production. The manufacturing method of the carbonaceous material according to the present application does not require the addition of a conductive agent, nor does it require the addition of other auxiliaries. Therefore, the carbonaceous material obtained by the manufacturing method according to the present application has a lower content of impurity atoms.

[0112] In the present application, the "organic carbon source" is a general term for substances rich in carbon elements that can form carbonaceous materials. In some embodiments, in S10, the organic carbon source includes one or more of biomass materials and thermoplastic resin materials. Optionally, the organic carbon source includes a biomass material. In some embodiments, the organic carbon source may include only biomass materials.

[0113] As the biomass material, materials known in the art suitable for the production of carbonaceous materials can be used. In some embodiments, the biomass material may include one or more of energy crops and biomass waste. For example, the biomass material includes, but is not limited to, one or more of wood, straw, bamboo, bark, and fruit shells.

[0114] In some embodiments, the thermoplastic resin material can include one or more of phenolic resin, acrylic resin, polyvinyl chloride, polycarbonate, epoxy resin, polyoxymethylene, coumarone resin, and petroleum resin.

[0115] In some embodiments, in S20, the crushing can employ a process known in the art suitable for performing crushing in the production of carbonaceous materials. For example, the crushing includes, but is not limited to, ball mill or jet mill crushing.

[0116] The order of washing with an acidic solution and washing with an alkaline solution is not particularly limited. In some embodiments, in S30, the process of the washing and impurity removal treatment includes, in order, the steps of washing with an acidic solution, water washing, washing with an alkaline solution, water washing, and drying. In some embodiments, in S30, the process of the washing and impurity removal treatment includes, in order, the steps of washing with an alkaline solution, water washing, washing with an acidic solution, water washing, and drying. Deionized water may be used during water washing, and the number of water washing times may be once or multiple times. It is considered that the water washing step is completed until the pH of the filtrate becomes neutral (i.e., pH is 7 ± 0.5). Drying may be air drying or vacuum drying. It is considered that the drying step is completed when the mass change rate of the material after a 2-hour interval is <0.1 wt%.

[0117] In this application, parameters such as the types of solutes, concentrations, washing temperatures, and washing times of the acidic solution and the alkaline solution are not particularly limited, as long as impurities can be sufficiently removed.

[0118] In some embodiments, in S30, the H + concentration of the acidic solution is 0.1 mol / L - 6 mol / L, and optionally 1 mol / L - 6 mol / L.

[0119] In some embodiments, in S30, the washing temperature of the acidic solution is 10°C - 95°C, and optionally 30°C - 95°C.

[0120] In some embodiments, in S30, the washing time of the acidic solution is 1 h - 24 h, and optionally 10 h - 24 h.

[0121] In some embodiments, in S30, the solute of the acidic solution includes one or more of hydrochloric acid, nitric acid, sulfuric acid, and perchloric acid, and the solvent includes water. Thereby, while ensuring sufficient removal of metal impurities, other impurity elements are not introduced.

[0122] H of the acidic solution +Adjusting one or more of the concentration, washing temperature, washing time, type of solute, etc. within the above ranges is advantageous for achieving sufficient washing and more preferably removing metal impurities.

[0123] In some embodiments, in S30, the OH of the alkaline solution - concentration is 0.1 mol / L - 6 mol / L, and optionally 1 mol / L - 6 mol / L.

[0124] In some embodiments, in S30, the washing temperature of the alkaline solution is 10°C - 95°C, and optionally 30°C - 95°C.

[0125] In some embodiments, in S30, the washing time of the alkaline solution is 1 h - 24 h, and optionally 10 h - 24 h.

[0126] In some embodiments, in S30, the solute of the alkaline solution includes NaOH, KOH, or a combination thereof, and the solvent includes water. This ensures sufficient removal of Si-containing impurities, etc., without introducing other impurity elements.

[0127] OH of the alkaline solution - Adjusting one or more of the concentration, washing temperature, washing time, solute type, etc. within the above ranges is advantageous for achieving sufficient washing.

[0128] In some embodiments, in S40, the temperature T1 is 1000°C - 1600°C, and may be, for example, a range consisting of any value from 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1350°C, 1400°C, 1450°C, 1500°C, 1550°C, 1600°C or above. Optionally, the temperature T1 is 1150°C - 1500°C.

[0129] When the temperature T1 is within the above range, the closed pore effect of the carbonaceous material is good, the size of the pore structure is small, and there is a large active ion storage space. Therefore, the capacity of the carbonaceous material is high. At the same time, the infiltration region of the electrolyte inside the carbonaceous material is low, and the consumption of active ions due to the formation of the SEI film is low. Therefore, the initial irreversible capacity loss of the carbonaceous material is low, and the initial Coulombic efficiency is high.

[0130] If the temperature T1 is too low, the true density of the obtained carbonaceous material is small and the interlayer distance is large. In this case, a large amount of water vapor is adsorbed into the interlayer structure and the adsorbed mass of water vapor is high. However, since this part of the interlayer structure of the carbonaceous material cannot effectively store active ions, the capacity and initial Coulombic efficiency of the carbonaceous material decrease.

[0131] If the temperature T1 is too high, the true density of the obtained carbonaceous material is large and the interlayer distance is small. Therefore, the insertion and desorption of active ions become difficult, and the capacity and initial Coulombic efficiency of the carbonaceous material decrease.

[0132] In some embodiments, in S40, the time t1 may be 1 h or more (≧1 h), for example, 2 h or more, 4 h or more, 6 h or more, 8 h or more, 10 h or more, 12 h or more, 14 h or more, or 16 h or more. When the heat preservation time t1 is within the above range, the content of impurity atoms in the carbonaceous material can be effectively reduced, and the carbonaceous material can be given a high initial Coulombic efficiency. If the heat preservation time t1 is short, some surface oxygen-containing functional groups of the carbonaceous material cannot be effectively reduced. Therefore, the content of oxygen impurity atoms in the finally produced carbonaceous material is high. After the oxygen impurity atoms combine with active ions, the active ions cannot be reversibly desorbed, and the initial Coulombic efficiency of the carbonaceous material further decreases.

[0133] Also, it is not preferable that the heat preservation time t1 is too long, because it causes waste of energy due to too high energy consumption. In some embodiments, optionally, the time t1 is 1 h - 24 h, 2 h - 24 h, 5 h - 24 h, 10 h - 24 h.

[0134] In some embodiments, in S40, the rate of temperature increase may be 0.05 °C / min - 1 °C / min, 0.06 °C / min - 1 °C / min, 0.08 °C / min - 1 °C / min, or 0.1 °C / min - 1 °C / min. Thereby, the production efficiency can be improved and the waste of energy can be reduced.

[0135] In some embodiments, in S40, the protective gas may include a mixed gas of hydrogen gas and an inert gas, and the volume concentration of the hydrogen gas is greater than 0 and less than or equal to 5%, optionally 1% - 5%. The volume concentration of hydrogen gas is mainly less than or equal to 5% (≤5%) from the perspective of safety. The inert gas may include nitrogen gas, argon gas, helium gas, or a combination thereof.

[0136] During the carbonization process, if the pressure in the furnace chamber is too low, due to the negative pressure effect, the raw material powder will float and escape into the furnace chamber, resulting in the contamination of the furnace chamber, a decrease in the yield, and an increased likelihood of dust and protective gas entering the exhaust gas pipeline simultaneously, increasing the risk of dust explosion. In some embodiments, in S40, the pressure in the furnace chamber is -5 kPa to -2 kPa, optionally -5 kPa to -3 kPa. This is advantageous for ensuring safe production.

[0137] In some embodiments, the manufacturing method further includes a secondary crushing treatment step S50 to crush the carbonaceous material obtained in S40. At this time, the carbonaceous material that may aggregate during the manufacturing process is crushed so that the carbonaceous material has a desired particle size, facilitating the production of the negative electrode slurry and the negative electrode sheet. Of course, in some embodiments, this step may be omitted.

[0138] In some embodiments, the manufacturing method includes a raw material providing step S10, in which the raw material is an organic carbon source; a crushing treatment step S20, in which the raw material is crushed to a desired particle size; a washing and impurity removal treatment step S30, in which the crushed raw material obtained in S20 is subjected to washing and impurity removal treatment, and the process of the washing and impurity removal treatment includes at least a washing step with an acidic solution and a washing step with an alkaline solution; and a carbonization treatment step S40, in which the washed and impurity-removed raw material obtained in S30 is put into a kiln furnace, a protective gas containing hydrogen gas is introduced, the pressure in the furnace chamber is controlled to be ≤ -2 kPa, then the temperature is raised to 1000°C - 1600°C at a rate of ≤ 1°C / min, and further heat preservation treatment is carried out at this temperature for 1 h - 24 h. After completion, a carbonaceous material is obtained. Here, the carbonaceous material is subjected to an adsorption test using water vapor under constant temperature and humidity conditions of 25°C and 100% RH and left standing for 100 h. Then, the adsorbed mass of water vapor is taken as A, the initial mass of the carbonaceous material is taken as B, and 0.13 ≤ A / B ≤ 0.50. The carbonaceous material obtained in this way can better balance high capacity and initial coulomb efficiency, and can further improve the energy density, service life, and rate performance of the secondary battery. Secondary battery

[0139] A third aspect of the embodiments of the present application provides a secondary battery.

[0140] In the examples or embodiments of the present application, the secondary battery mentioned refers to a single physical module including one or more battery cells to provide a higher voltage and capacity. For example, the secondary battery referred to in the present application can include battery cells, battery modules, or battery packs, etc. A battery cell is the smallest unit constituting a secondary battery and can perform the functions of charge and discharge independently. In the present application, the shape of the battery cell is not particularly limited and may be cylindrical, square, or any other shape. FIG. 1 shows, as an example, a square-structured battery cell 5.

[0141] In some embodiments, the battery cell includes an electrode assembly and an electrolyte, and the battery cell may further include an exterior. The exterior is used to seal the electrode assembly and the electrolyte. The exterior may be a rigid case such as a rigid plastic case, an aluminum case, or a steel case. The exterior may also be a soft pack, for example, a pouch soft pack. The material of the soft bag may be one or more of plastics such as polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0142] The electrode assembly generally includes a positive electrode sheet, a negative electrode sheet, etc. During the charge and discharge process of the secondary battery, active ions reciprocate and insert and desorb between the positive electrode sheet and the negative electrode sheet, and the electrolyte plays a role in conducting active ions between the positive electrode sheet and the negative electrode sheet. The electrode assembly can be manufactured by a winding process and / or a lamination process.

[0143] In some embodiments, as shown in FIG. 2, the exterior may include a case 51 and a cover plate 53. The case 51 includes a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates surround to form a receiving cavity. The case 51 has an opening communicating with the receiving cavity, and the cover plate 53 covers the opening to close the receiving cavity. The electrode assembly 52 is packaged in the receiving cavity. The number of electrode assemblies 52 included in the battery cell 5 may be one or more and can be adjusted as needed.

[0144] In some embodiments of the present application, the battery cells may be assembled into a battery module. The number of battery cells included in the battery module may be plural, and the specific number may be adjusted according to the application and capacity of the battery module. FIG. 3 is a schematic diagram of a battery module 4 as an example. As shown in FIG. 3, in the battery module 4, a plurality of battery cells 5 may be sequentially arranged along the longitudinal direction of the battery module 4. Of course, they may be arranged in any other manner. Further, the plurality of battery cells 5 may be fixed by fasteners.

[0145] Optionally, the battery module 4 may further include a housing having an accommodation space for accommodating a plurality of battery cells 5.

[0146] In some embodiments, the above battery module may be assembled into a battery pack, and the number of battery modules included in the battery pack can be adjusted according to the use and capacity of the battery pack. FIGS. 4 and 5 are schematic diagrams of a battery pack 1 as an example. As shown in FIGS. 4 and 5, the battery pack 1 may include a battery box and a plurality of battery modules 4 provided in the battery box. The battery box includes an upper housing 2 and a lower housing 3. The upper housing 2 covers the lower housing 3 and forms a sealed space for accommodating the battery module 4. The plurality of battery modules 4 may be arranged in the battery box in any manner. [Negative electrode sheet]

[0147] In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector. For example, the negative electrode current collector has two surfaces facing each other in the thickness direction, and the negative electrode film layer is provided on either one or both of the two opposing surfaces of the negative electrode current collector.

[0148] In some embodiments, the negative electrode film layer includes the carbonaceous material of the first aspect of the embodiments of the present application or the carbonaceous material manufactured by the method described in the second aspect of the embodiments of the present application. Thereby, the secondary battery can achieve both high energy density, long service life, and good rate characteristics.

[0149] In some embodiments, the negative electrode film layer may further include other negative electrode active materials other than the above carbonaceous material. In some embodiments, the other negative electrode active materials include, but are not limited to, one or more of natural graphite, artificial graphite, soft carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may include one or more of silicon alone, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy material. The tin-based material may include one or more of tin alone, tin oxide, and tin alloy material.

[0150] In some embodiments, the negative electrode film layer may include a negative electrode conductive agent. In the present application, the type of the negative electrode conductive agent is not particularly limited. By way of example, the negative electrode conductive agent may include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0151] In some embodiments, the negative electrode film layer may include a negative electrode binder as needed. In the present application, the type of the negative electrode binder is not particularly limited. By way of example, the negative electrode binder may include one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, aqueous acrylic resin (for example, polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0152] In some embodiments, the negative electrode film layer may contain other auxiliaries. As an example, the other auxiliaries may include a thickening agent, such as sodium carboxymethyl cellulose (CMC), a PTC thermistor material, and the like.

[0153] In some embodiments, the negative electrode current collector can use a metal foil or a composite current collector. As an example of the metal foil, a copper foil can be used. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material may include one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0154] The negative electrode film layer is usually formed by applying a negative electrode slurry to a negative electrode current collector, drying, and cold pressing. The negative electrode slurry is usually formed by dispersing a negative electrode active material, an optional conductive agent, an optional binder, and an optional other auxiliary in a solvent and uniformly stirring. The solvent may be N-methylpyrrolidone (NMP) or deionized water, but is not limited thereto.

[0155] The negative electrode sheet does not exclude other additional functional layers other than the negative electrode film layer. For example, in some embodiments, the negative electrode sheet described in the present application further includes a conductive undercoat layer (for example, composed of a conductive agent and an adhesive) sandwiched between the negative electrode current collector and the negative electrode film layer and provided on the surface of the negative electrode current collector. In some embodiments, the negative electrode sheet according to the present application further includes a protective layer covering the surface of the negative electrode film layer. [Positive Electrode Sheet]

[0156] In some embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector. For example, the positive electrode current collector has two surfaces facing each other in the self-thickness direction, and the positive electrode film layer is provided on either one or both of the two opposing surfaces of the positive electrode current collector.

[0157] The positive electrode current collector can use a metal foil or a composite current collector. As an example of the metal foil, an aluminum foil can be used. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material may include one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0158] The positive electrode film layer usually includes a positive electrode active material, an optional binder, and an optional conductive agent. The positive electrode film layer is usually formed by applying a positive electrode slurry to the positive electrode current collector, drying, and cold pressing. The positive electrode slurry is usually formed by dispersing a positive electrode active material, an optional conductive agent, an optional binder, and any other components in a solvent and stirring uniformly. The solvent may be, but is not limited to, N-methylpyrrolidone (NMP). As an example, the binder used in the positive electrode film layer may include, for example, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a terpolymer of vinylidene fluoride-tetrafluoroethylene-propylene, a terpolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, a copolymer of tetrafluoroethylene-hexafluoropropylene, and a fluorine-containing acrylate resin. As an example, the conductive agent used in the positive electrode film layer includes one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0159] The positive electrode active material can employ a positive electrode active material for secondary batteries known in the art.

[0160] When the secondary battery of the present application is a lithium-ion battery, the positive electrode active material includes, but is not limited to, one or more of lithium-containing transition metal oxides, lithium-containing phosphates, and their modified compounds. Examples of the lithium transition metal oxides include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds. Examples of the lithium-containing phosphates include, but are not limited to, one or more of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite material of lithium manganese iron phosphate and carbon, and their modified compounds.

[0161] In some embodiments, in order to further improve the energy density of the secondary battery, the positive electrode active material used in the lithium-ion battery may include one or more of lithium transition metal oxides and their modified compounds having the general formula Li a Ni b Co c M d O e A f where 0.8 ≦ a ≦ 1.2, 0.5 ≦ b < 1, 0 < c < 1, 0 < d < 1, 1 ≦ e ≦ 2, 0 ≦ f ≦ 1, M includes one or more selected from Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B, and A includes one or more selected from N, F, S, and Cl.

[0162] For example, the positive electrode active material used in the lithium-ion battery is LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), LiNi 0.85 Co 0.15 Al 0.05 O 2 , LiFePO 4 and LiMnPO 4 may include one or more of these.

[0163] When the secondary battery of the present application is a sodium ion battery, the positive electrode active material includes, but is not limited to, one or more of sodium-containing transition metal oxides, polyanion materials (e.g., phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue-based materials.

[0164] As an example, the positive electrode active material for a sodium ion battery is NaFeO 2 , NaCoO 2 , NaCrO 2 , NaMnO 2 , NaNiO 2 , NaNi 1 / 2 Ti 1 / 2 O 2 , NaNi 1 / 2 Mn 1 / 2 O 2 , Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O 2 , NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 , NaFePO 4 , NaMnPO 4 , NaCoPO 4 , Prussian blue-based materials, and those with the general formula X p M’ q(PO 4 ) r O x Y 3-x can include one or more of the materials that are. General formula X p M’ q (PO 4 ) r O x Y 3-x where 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, X is H + , Li + , Na + , K + and NH 4 + including one or more selected from, M’ is a transition metal cation, optionally including one or more selected from V, Ti, Mn, Fe, Co, Ni, Cu and Zn, Y is a halogen anion, optionally including one or more selected from F, Cl and Br.

[0165] In the present application, the modified compound of each of the above positive electrode active materials is obtained by performing doping modification and / or surface coating modification on the positive electrode active material. [Electrolyte]

[0166] In the present application, the type of the electrolyte is not particularly limited and can be selected according to actual needs. For example, the electrolyte may be at least one selected from a solid electrolyte and a liquid electrolyte (i.e., an electrolytic solution).

[0167] In some embodiments, the electrolyte uses an electrolytic solution containing an electrolyte salt and a solvent.

[0168] The type of the electrolyte salt is not specifically limited and can be selected according to actual needs.

[0169] When the secondary battery of the present application is a lithium ion battery, for example, the electrolyte salt is lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4) Lithium perchlorate (LiClO 4 ) Lithium hexafluoroarsenate (LiAsF 6 ) One or more of lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluoroborate (LiDFOB), lithium diborate (LiBOB), lithium difluorophosphate (LiPO 2 F 2 ) lithium difluorodiphosphate (LiDFOP), and lithium tetrafluoroborate (LiTFOP).

[0170] When the secondary battery of the present application is a sodium ion battery, the electrolyte salt is sodium hexafluorophosphate (NaPF 6 ) sodium tetrafluoroborate (NaBF 4 ), sodium perchlorate (NaClO 4 ), sodium hexafluoroarsenate (NaAsF 6 ), sodium bis(fluorosulfonyl)imide (NaFSI), sodium (bis(trifluoromethanesulfonyl)imide) (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluoroborate (NaDFOB), sodium diborate (NaBOB), sodium difluorophosphate (NaPO 2 F 2 ), sodium difluorodiphosphate (NaDFOP), and sodium tetrafluoroborate (NaTFOP).

[0171] The type of the solvent is not specifically limited and can be selected according to actual needs. In some embodiments, by way of example, the solvent may include one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0172] In some embodiments, the electrolyte may optionally contain additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performance of the battery, such as additives for improving the overcharge performance of the battery, additives for improving the high-temperature performance of the battery, additives for improving the low-temperature output performance of the battery, and the like. [Separator]

[0173] Secondary batteries using electrolytes and secondary batteries using solid electrolytes also include separators. The separator is provided between the positive electrode sheet and the negative electrode sheet and serves as an insulator. In the present application, the type of the separator is not particularly limited, and any known porous structure separator having good chemical stability and mechanical stability can be selected.

[0174] In some embodiments, the material of the separator may include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. [Manufacturing method]

[0175] The manufacturing method of the secondary battery of the present application is known. In some embodiments, a secondary battery can be formed by assembling a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte. For example, a positive electrode sheet, a separator, and a negative electrode sheet are formed into an electrode assembly by a winding process and / or a lamination process, the electrode assembly is placed in an exterior package, the electrolyte is injected after drying, and through steps such as vacuum sealing, standing, formation, and shaping, a battery cell can be obtained. A plurality of battery cells may be further connected in series or in parallel or in a series-parallel hybrid manner to form a battery module. A plurality of battery modules may form a battery pack via series or parallel or series-parallel hybrid connection. In some embodiments, a plurality of battery cells may directly form a battery pack.

[0176] Power consumption device

[0177] The fourth aspect of the embodiment of the present application provides a power consumption device including the secondary battery of the present application. The secondary battery may be used as a power source of the power consumption device or as an energy storage means of the power consumption device. The power consumption device may be a portable device (for example, a mobile phone, a tablet computer, a notebook computer, etc.), an electric vehicle (for example, a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship, a satellite, an energy storage system, etc., but is not limited thereto.

[0178] The power consumption device can select a specific type of secondary battery, such as a battery cell, a battery module, or a battery pack, according to its usage needs.

[0179] FIG. 6 is a schematic diagram of a power consumption device as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or the like. In order to meet the requirements for high output and high energy density of the power consumption device, a battery pack or a battery module can be adopted as the power source.

[0180] The power consumption device as another example may be a mobile phone, a tablet computer, a notebook computer, or the like. The power consumption device is usually required to be thin, and a battery cell can be adopted as the power source. Example

[0181] The following examples are used to more specifically illustrate the disclosure content of the present application. Since it is obvious to those skilled in the art that various modifications and changes can be made within the scope of the disclosure content of the present application, these examples are only illustrative. Unless otherwise specified, all parts, percentages, and ratios described in the following examples are based on mass. All reagents used in the examples are commercially available or obtained by synthesis according to conventional methods and can be directly used without further treatment. Also, the equipment used in the examples is commercially available. Example 1

[0182] Commercially available coconut shells were crushed with a jet mill until the volume particle size D50 reached 6.8 ± 0.5 μm and D90 reached 13.7 ± 0.5 μm. Then, they were washed with a 3 mol / L perchloric acid aqueous solution at 60 °C for 12 h, and then washed with deionized water until neutral. Subsequently, they were washed with a 3 mol / L NaOH aqueous solution at 95 °C for 24 h, and further washed with deionized water until neutral. Then, they were dried by blowing air to remove moisture. The dried powder material was placed in a kiln furnace. Under the conditions of a mixed gas atmosphere with a volume ratio of hydrogen gas / argon gas of 5:95 and a furnace chamber pressure of -5 kPa, after heating to 1400 °C at a rate of 0.1 °C / min, it was heat-insulated for 24 h. After completion, a carbonaceous material was obtained.

[0183] In a constant temperature and humidity chamber at 25 °C and 100% RH, the carbonaceous material with mass B was evenly placed in a watch glass with a diameter of 10 cm, and the deposition thickness of the carbonaceous material was set to ≤ 0.2 cm. After standing for 100 h, the increased mass of the carbonaceous material was weighed and designated as the adsorbed mass A of water vapor.

[0184] The true density of the carbonaceous material was measured using the Archimedes immersion volume replacement method with n-butanol as the medium. Examples 2-16 and Comparative Examples 1-6

[0185] The manufacturing method of the carbonaceous material was similar to that of Example 1, and the difference was that the parameters of the manufacturing process of the carbonaceous material were adjusted. Specifically, refer to Table 1. Comparative Example 7

[0186] Commercially available coconut shells were crushed with a jet mill until the volume particle size D50 reached 6.8 ± 0.5 μm and D90 reached 13.7 ± 0.5 μm. Then, they were washed with a 3 mol / L perchloric acid aqueous solution at 60 °C for 12 h, and then washed with deionized water until neutral. Subsequently, they were dried by blowing air to remove moisture. The dried powder material was placed in a kiln furnace. Under the conditions of a mixed gas atmosphere with a volume ratio of hydrogen gas / argon gas of 5:95 and a furnace chamber pressure of -5 kPa, after heating to 1400 °C at a rate of 0.1 °C / min, it was heat-insulated for 24 h. After completion, a carbonaceous material was obtained. Comparative Example 8

[0187] Commercially available coconut shells were crushed with a jet mill until the volume particle size D50 reached 6.8 ± 0.5 μm and D90 reached 13.7 ± 0.5 μm. Then, they were washed with a 3 mol / L NaOH aqueous solution at 95 °C for 24 h, and further washed with deionized water until neutral. After that, they were dried by blowing air to remove moisture. The dried powder material was put into a kiln furnace. Under the conditions of a mixed gas atmosphere with a hydrogen gas / argon gas volume ratio of 5:95 and a furnace chamber pressure of -5 kPa, the temperature was raised to 1400 °C at a rate of 0.1 °C / min, and then heat preservation treatment was carried out for 24 h. After completion, a carbonaceous material was obtained. Comparative Example 9

[0188] Commercially available coconut shells were crushed with a jet mill until the volume particle size D50 reached 6.8 ± 0.5 μm and D90 reached 13.7 ± 0.5 μm. Then, the powder material was put into a kiln furnace. Under the conditions of a mixed gas atmosphere with a hydrogen gas / argon gas volume ratio of 5:95 and a furnace chamber pressure of -5 kPa, the temperature was raised to 1400 °C at a rate of 0.1 °C / min, and then heat preservation treatment was carried out for 24 h. After completion, a carbonaceous material was obtained. Comparative Example 10

[0189] Commercially available coconut shells were washed with a 3 mol / L perchloric acid aqueous solution at 60 °C for 12 h, and then washed with deionized water until neutral. Further, they were washed with a 3 mol / L NaOH aqueous solution at 95 °C for 24 h, and then washed with deionized water until neutral. After that, they were dried by blowing air to remove moisture. The dried coconut shells were crushed with a jet mill until the volume particle size D50 reached 6.8 ± 0.5 μm and D90 reached 13.7 ± 0.5 μm. Then, the powder material was put into a kiln furnace. Under the conditions of a mixed gas atmosphere with a hydrogen gas / argon gas volume ratio of 5:95 and a furnace chamber pressure of -5 kPa, the temperature was raised to 1400 °C at a rate of 0.1 °C / min, and then heat preservation treatment was carried out for 24 h. After completion, a carbonaceous material was obtained. Performance test

[0190] The carbonaceous materials produced in each example and comparative example, styrene-butadiene rubber (SBR) as a binder, sodium carboxymethyl cellulose (CMC-Na) as a thickener, and carbon black as a conductive agent were sufficiently stirred and mixed with deionized water, an appropriate amount of solvent, at a mass ratio of 96.2:1.8:1.2:0.8 to form a uniform negative electrode slurry. The negative electrode slurry was uniformly coated on the surface of a copper foil, which is a negative electrode current collector, and dried in an oven for use. After mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) at a volume ratio of 1:1:1 to obtain an organic solvent, NaPF 6 was dissolved therein to prepare an electrolyte solution with a concentration of 1 mol / L. Then, using a metal sodium sheet as a counter electrode and a polyethylene (PE) film as a separator, a CR2430-type coin cell was assembled in a glove box protected by argon gas.

[0191] At 25 °C, first, the coin cells prepared in each example and comparative example were discharged at a constant current density of 10 mA / g to 0 V, and the initial charge capacity of the coin cell was recorded. Then, they were charged at a constant current density of 10 mA / g to 2.0 V, and the initial charge capacity of the coin cell was recorded.

[0192] Reversible gram capacity of carbonaceous material (mAh / g) = Initial charge capacity of coin cell / Mass of carbonaceous material

[0193] Initial coulombic efficiency of carbonaceous material (%) = Initial charge capacity of coin cell / Initial discharge capacity of coin cell × 100%.

[0194]

Table 1

[0195] Figures 7 and 8 are photographs of a scanning electron microscope of the carbonaceous material according to the present application. As shown in Figures 7 and 8, the morphology of the carbonaceous material according to the present application is random polygons. Summarizing the test results in Table 1, it can be seen that when the mass of water vapor adsorbed by the carbonaceous material per unit mass within 100 h is between 0.13 and 0.50 under the constant temperature and humidity conditions of 25°C and 100% RH, the carbonaceous material can achieve both high capacity and initial Coulomb efficiency.

[0196] The carbonaceous materials produced in Comparative Examples 1-10 cannot achieve both high capacity and initial Coulomb efficiency because the mass of water vapor adsorbed by the carbonaceous material per unit mass within 100 h is less than 0.13 or exceeds 0.50 under the constant temperature and humidity conditions of 25°C and 100% RH.

[0197] Summarizing the test results of Examples 1, 8-10, it can also be seen that when the parameter A / B of the carbonaceous material is close, due to the high true density of the carbonaceous material, the capacity and initial Coulomb efficiency of the carbonaceous material can be further improved. The reason is that the interlayer distance of the carbonaceous material obtained in Example 8 is large, and in this situation, a large amount of water vapor is adsorbed into the interlayer structure, resulting in a high mass of adsorbed water vapor. However, n-butanol liquid cannot enter the interlayer structure of the carbonaceous material, so the test value of the true density becomes low. In addition, the carbonaceous material obtained in Example 8 cannot efficiently store active ions in its interlayer structure, so the capacity and initial Coulomb efficiency are both lower than those in Examples 1, 9-10.

[0198] Therefore, when the carbonaceous material simultaneously satisfies that the mass of water vapor adsorbed by the carbonaceous material per unit mass within 100 h is between 0.13 and 0.50 and the true density ρ is between 1.0 g / cm 3 -1.6 g / cm 3 , and optionally between 1.05 g / cm 3 -1.45 g / cm 3 , the capacity and initial Coulomb efficiency of the carbonaceous material can be further improved.

[0199] Note that this application is not limited to the above embodiments. The above embodiments are merely exemplary. Any configuration that has a substantially identical structure to the technical idea within the technical scope of this application and exhibits the same operational effects is included in the technical scope of this application. Also, within the scope not departing from the gist of this application, various modifications conceived by those skilled in the art applied to the embodiments, as well as other forms constructed by combining some of the components in the embodiments, are also included within the scope of this application.

Description of Reference Numerals

[0200] 1 Battery pack 2 Upper housing 3 Lower housing 4 Battery module 5 Battery cell 51 Case 52 Electrode assembly 53 Cover plate

Claims

1. A carbonaceous material, which is subjected to an adsorption test using water vapor under constant temperature and humidity conditions of 25°C and 100% RH and left standing for 100 h. After that, when the adsorbed mass of water vapor is A and the initial mass of the carbonaceous material is B, 0.13 ≤ A / B ≤ 0.

50. The carbonaceous material.

2. 0.15 ≤ A / B ≤ 0.50, and optionally, 0.30 ≤ A / B ≤ 0.

496. The carbonaceous material according to Claim 1.

3. The true density ρ of the carbonaceous material is 1.0 g / cm ３ -1.6 g / cm ３ and optionally, 1.05 g / cm ３ -1.45 g / cm ３ The carbonaceous material according to claim 1 or 2, which is such.

4. The carbonaceous material according to any one of Claims 1 to 3, wherein the carbonaceous material includes a plurality of nanoporous structures, and optionally includes a pore structure with a plurality of pore diameters of 10 nm or less.

5. In the Raman spectrum of the carbonaceous material, I ｄ / I ｇ is 1.0 - 1.3, and optionally 1.05 - 1.15, where I ｄ represents the intensity of the d peak within the range of a Raman shift of 1350 ± 50 cm －１ , I ｇ represents the intensity of the g peak within the range of a Raman shift of 1580 ± 50 cm －１ , and / or The interlayer distance of the (002) crystal plane of the carbonaceous material is 0.37 nm or more, optionally 0.37 nm - 0.42 nm, and / or In the X-ray diffraction spectrum of the carbonaceous material, the 2θ value corresponding to the peak of the (002) crystal plane is 22° - 24°. The carbonaceous material according to any one of Claims 1 to 4.

6. The carbonaceous material satisfies at least one of the following conditions (1) - (5): (1) The volume particle size Dv50 of the carbonaceous material is 3 μm - 7 μm, and optionally 4 μm - 6 μm. (2) The volume particle size Dv90 of the carbonaceous material is 8 μm - 15 μm, and optionally 9 μm - 12 μm. (3) The specific surface area of the carbonaceous material is 0.1 m ２ / g - 10 m ２ / g, and optionally 1 m ２ / g - 5 m ２ / g, and (4) The powder compression density of the carbonaceous material under a 50,000 N acting force is 0.90 g / cm ３ - 1.05 g / cm ３ and optionally 0.93 g / cm ３ - 1.02 g / cm ３ and (5) The tap density of the carbonaceous material is 0.80 g / cm ３ - 0.95 g / cm ３ and optionally 0.85 g / cm ３ - 0.90 g / cm ３ is The carbonaceous material according to any one of Claims 1 to 5.

7. A method for producing a carbonaceous material, comprising: A raw material providing step S10, which is a step in which the raw material is an organic carbon source; A crushing treatment step S20, which is a step of crushing the raw material to a desired particle size; A washing and impurity removal treatment step S30, which performs a washing and impurity removal treatment on the crushed raw material obtained in S20. The process of the washing and impurity removal treatment includes at least a washing step with an acidic solution and a washing step with an alkaline solution; A carbonization treatment step S40, which puts the washed and impurity-removed raw material obtained in S30 into a kiln furnace, introduces a protective gas containing hydrogen gas, controls the pressure in the furnace chamber to ≤ -2 kPa, then raises the temperature to a target temperature T1 at a rate of ≤ 1°C / min, holds the temperature at the target temperature T1 for a target time t1, and obtains a carbonaceous material after completion. The carbonaceous material is subjected to an adsorption test using water vapor under constant temperature and humidity conditions of 25 °C and 100% RH, and after standing for 100 h, if the adsorbed mass of water vapor is A and the initial mass of the carbonaceous material is B, then 0.13 ≦ A / B ≦ 0.

50. A method for producing a carbonaceous material.

8. The method according to claim 7, wherein in S20, the crushing includes ball mill crushing or jet mill crushing.

9. In S30, the process of the washing and impurity removal treatment includes, in order, the steps of washing with an acidic solution, washing with water, washing with an alkaline solution, washing with water, and drying, or In S30, the process of the washing and impurity removal treatment includes, in order, the steps of washing with an alkaline solution, washing with water, washing with an acidic solution, washing with water, and drying. The method according to claim 7 or 8.

10. In S30, the acidic solution satisfies at least one of the following conditions (1)-(4): (1) The H of the acidic solution ＋ concentration is 0.1 mol / L - 6 mol / L, and optionally 1 mol / L - 6 mol / L, (2) The washing temperature of the acidic solution is 10 °C - 95 °C, and optionally 30 °C - 95 °C. (3) The washing time of the acidic solution is 1 h - 24 h, and optionally 10 h - 24 h. (4) The solute of the acidic solution includes one or more of hydrochloric acid, nitric acid, sulfuric acid, and perchloric acid, and the solvent includes water. The method according to any one of claims 7 to 9.

11. In S30, the alkaline solution satisfies at least one of the following conditions (1)-(4): (1) OH of the alkaline solution － The concentration is 0.1 mol / L - 6 mol / L, and optionally 1 mol / L - 6 mol / L, (2) The washing temperature of the alkaline solution is 10 °C - 95 °C, and optionally 30 °C - 95 °C. (3) The washing time of the alkaline solution is 1 h - 24 h, and optionally 10 h - 24 h. (4) The solute of the alkaline solution includes NaOH, KOH, or a combination thereof, and the solvent includes water. The method according to any one of claims 7 to 10.

12. In S40, the temperature T1 is 1000 °C - 1600 °C, and optionally 1150 °C - 1500 °C, and / or In S40, the time t1 is 1 h or more, and optionally 10 h - 24 h, and / or In S40, the heating rate is 0.05 °C / min - 1 °C / min, and optionally 0.1 °C / min - 1 °C / min, and / or In S40, the protective gas includes a mixed gas of hydrogen gas and an inert gas, and the volume concentration of the hydrogen gas is greater than 0 and 5% or less, and optionally 1% - 5%. In S40, the pressure in the furnace chamber is from -5 kPa to -2 kPa, and optionally from -5 kPa to -3 kPa. The method according to any one of claims 7 to 11.

13. In S10, the organic carbon source includes one or more of biomass materials and thermoplastic resin materials. Optionally, the biomass material includes one or more of energy crops and biomass waste. Optionally, the thermoplastic resin material includes one or more of phenolic resin, acrylic resin, polyvinyl chloride, polycarbonate, epoxy resin, polyoxymethylene, coumarone resin, and petroleum resin. The method according to any one of claims 7 to 12.

14. A secondary battery comprising a negative electrode sheet including the carbonaceous material according to any one of claims 1 to 6 or the carbonaceous material produced by the method according to any one of claims 7 to 13.

15. An electric power consuming device comprising the secondary battery according to claim 14.

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