Patent Application
20250158137
The present disclosure relates to a field of anode material, and particularly, to an anode material, a method for preparing the anode material, and a lithium ion battery.
At present, silicon-carbon materials are one of the most advanced anode materials for achieving excellent performance such as high initial Coulomb efficiency, high capacity, long cycle, and low expansion in secondary batteries. The existing silicon-carbon anode materials often have many pores, these pores may adsorb gas molecules from the air, such as oxygen and nitrogen, during the production process. However, the solubility of these gas molecules in aqueous electrolytes is relatively low (0.031 L oxygen/0.024 L nitrogen dissolved in 1 L water at 20° C. standard atmospheric pressure), so that the electrolyte is blocked by gas molecules and then is difficult to fill into the pores of the anode material, thereby seriously affecting the electrochemical performance of silicon-carbon anode materials.
Carbon dioxide is a greenhouse gas that exists in large quantities. Its emission amounts have been increasing year by year with the process of human industrialization, leading to a rise in global temperatures and posing a serious threat to human survival. Therefore, various countries in the world have implemented a series of measures to reduce carbon dioxide emissions, striving to mitigate or even eliminate the survival crisis caused by the greenhouse effect of carbon dioxide. In the electrochemical reaction process of secondary batteries, the FEC (fluoroethylene carbonate) contained in the electrolyte partially decompose during lithium intercalation process, producing CO2 and solid decomposition products (such as types of LiF, —CHF—OCO2 compounds, etc.), forming LiF dominated SEI and “adhesion effect”. Therefore, the generation of CO2 is beneficial to the absorption of electrolyte by anode materials. However, the initial generation of CO2 often occurs at a fast rate, which leads to the formation of loose and irregular SEI and even cracks, thereby affecting the initial coulomb efficiency and capacity of silicon-carbon anode materials.
The purpose of the present disclosure is to provide an anode material and a preparation method thereof, and a lithium ion battery. The carbon dioxide in the pores of the carbon substrate in the anode material of the present disclosure may quickly dissolve in the electrolyte and promote the electrolyte to enter the pores of the anode material. Meanwhile, during the lithium intercalation process, the dissolved carbon dioxide may reduce the decomposition rate of fluoroethylene carbonate (FEC), reduce the formation of loose and irregular SEI, increase the bonding effect between fluorine in the lithium fluoride SEI and lithium in the lithium-silicon alloy, thereby improving the capacity and initial coulomb efficiency of the anode material.
In a first aspect, the present disclosure provides an anode material including a carbon substrate and an active material, the carbon substrate has pores, and the active material is distributed within the pores of the carbon substrate.
In the infrared spectrum of the anode material, there are a first absorption peak and the first absorption peak located at 2375±1 cm−1, denoted as A1, and a first valley located at 2394±1 cm−1, denoted as A0; and a second absorption peak at 2919±1 cm−1, denoted as B1; and a second valley located at 2821±1 cm−1, denoted as B0.
The anode material has a carbon dioxide adsorption index P, wherein P=(A1−A0)/(B1−B0), and 0.25≤P<0.70.
In some embodiments, the carbon substrate includes porous carbon.
In some embodiments, the active material includes nano-silicon.
In some embodiments, the active material includes nano-silicon, and the nano-silicon includes crystalline silicon and/or amorphous silicon.
In some embodiments, the carbon substrate has an average particle size ranging from 8 μm to 15 μm.
In some embodiments, a mass content of the carbon element in the anode material ranges from 49% to 51%.
In some embodiments, a mass content of active material in the anode material ranges from 45% to 50%.
In some embodiments, the anode material contains oxygen element, and the mass content of the oxygen element in the anode material ranges from 1.0% to 4%.
In some embodiments, the anode material has an average particle size ranges from 0.8 μm to 25 μm.
In some embodiments, the anode material has a specific surface area ranging from 1 m2/g to 300 m2/g.
In some embodiments, the anode material has pores, and the pores in the anode material include micro-pores, meso-pores and macro-pores.
In some embodiments, the pores in the anode material have an average pore size ranging from 1 nm to 10 nm.
In some embodiments, a total pore volume of the anode material ranged from 0.001 cm3/g to 0.20 cm3/g.
In some embodiments, the anode material has pores, the pores in the anode material include micro-pores, and a pore volume of the micro-pore has a volume proportion of 30% to 65% of the total pore volume of all pores.
In some embodiments, the anode material has pores, the pores in the anode material include meso-pores, and a pore volume of the meso-pore has a volume proportion of 35% to 70% of a total pore volume of all pores.
In some embodiments, the anode material has pores, the pores in the anode material include macro-pores, and a pore volume of the macro-pore has a volume proportion of 0% to 5% of a total pore volume of all pores.
In a second aspect, the present disclosure provides a method for preparing an anode material. The method includes following steps:
In some embodiments, before introducing a carbon source gas to perform carbon deposition on the metal catalytic matrix, the method further includes: placing the metal catalytic matrix in an inert gas to perform air discharging treatment.
In some embodiments, a metal in the metal catalytic matrix includes at least one of iron, nickel, copper, gold, or an alloy.
In some embodiments, a metal in the metal catalytic matrix includes an alloy, and the alloy includes at least one of an iron-cobalt alloy, a nickel-copper alloy, and an iron-nickel-copper alloy.
In some embodiments, the inert gas includes at least one of nitrogen, argon, and helium.
In some embodiments, the inert gas has a flow rate ranging from 20 ccm to 200 sccm.
In some embodiments, the inert gas has an introduction time ranging from 0.5 h to 3 h.
In some embodiments, after introducing a reaction gas containing an active material and performing vapor deposition on the carbon substrate, the method further includes: introducing sequentially and repeatedly the carbon source gas and the reaction gas containing the active material for carbon deposition and vapor deposition for 4 h to 24 h.
In some embodiments, the carbon source gas includes at least one of methane, acetylene, ethane, and propane.
In some embodiments, the carbon source gas has a flow rate ranging from 10 sccm to 80 sccm.
In some embodiments, the carbon source gas has an introduction time ranging from 5 min to 30 min.
In some embodiments, the reaction gas containing the active material includes a silicon source gas.
In some embodiments, the reaction gas containing the active material includes a silicon source gas, and the silicon source gas includes silane and/or disilane.
In some embodiments, the reaction gas containing the active material includes a silicon source gas, and the silicon source gas has a flow rate of 10 sccm to 80 sccm.
In some embodiments, the reaction gas containing the active material includes a silicon source gas, and the silicon source gas has an introduction time ranging from 5 min to 30 min.
In some embodiments, a temperature of the carbon deposition and the vapor deposition ranges from 600° C. to 700° C.
In some embodiments, a heating rate of the carbon deposition and the vapor deposition ranges from 1° C./min to 12° C./min.
In some embodiments, the carbon deposition and the vapor deposition are performed in an inert gas.
In some embodiments, the carbon deposition and the vapor deposition are performed in the inert gas, and the inert gas includes at least one of nitrogen, argon, and helium.
In some embodiments, the carbon deposition and the vapor deposition are performed in the inert gas, and a flow rate of the inert gas ranges from 5 sccm to 50 sccm.
In some embodiments, the method further includes separating the metal catalytic matrix from a deposition product, and then sequentially performing mechanical pulverization and airflow pulverization on the deposition product.
In some embodiments, the mechanical pulverization has a time ranging from 0.5 h to 3 h.
In some embodiments, the airflow pulverization has a time ranging from 0.5 h to 3 h.
In a third aspect, the present disclosure provides a lithium ion battery, the lithium ion battery includes the anode material according to the first aspect or the anode material prepared by the method according to the second aspect.
Compared with the prior art, the technical solution of the present disclosure has at least following beneficial effects:
The anode materials provided by the present disclosure include a carbon substrate and an active material. The carbon substrate has pores, and the active material is distributed within the pores of the carbon substrate, allowing the anode material to maintain a high capacity; the carbon substrate may provide a certain volume space for the expansion of the active material, which is conducive to maintaining the structural stability of the anode material. The carbon substrate may also provide electron and ion transport pathways, improve lithium ion transport efficiency, and thus improving the initial coulomb efficiency of the anode material. Meanwhile, the pores of the carbon substrate contain carbon dioxide gas, which may quickly dissolve in the electrolyte and promote the electrolyte to enter the pores of the anode material. During the lithium intercalation process, the dissolved carbon dioxide gas may reduce the decomposition rate of fluoroethylene carbonate (FEC) in the electrolyte, reduce the formation of loose and irregular solid electrolyte interphase (SEI) on the surface of the anode material, increase the bonding effect between fluorine in the lithium fluoride SEI and lithium in the lithium silicon alloy, improve the interface stability of the lithium fluoride SEI, reduce the occurrence of side reactions, reduce the consumption of active lithium ions, and thus improving the capacity and initial coulomb efficiency of the anode material.
The present disclosure provides a preparation method of an anode material, firstly, the carbon source gas is deposited on the metal catalytic matrix to obtain a carbon substrate, the carbon substrate has pores, and the reaction gas containing the active material is introduced and vapor deposition is performed on the carbon substrate, in the processes of carbon deposition and vapor deposition, the metal catalytic matrix may improve deposition efficiency, accelerate the formation of the carbon substrate and the deposition of the active material, the active material may be fully filled into the pores of the carbon substrate, enable the prepared anode material to maintain a high capacity by vapor deposition; Meanwhile, the carbon substrate may provide a certain volume space for the expansion of the active material, which is conducive to maintaining the structural stability of the anode material, the carbon substrate may also provide electron and ion transport pathways, improve the lithium ion transport efficiency, and thus improving the initial coulomb efficiency of the anode material. In addition, the pores of the carbon substrate may adsorb carbon dioxide gas. The carbon dioxide gas adsorbed in the pores of the carbon substrate may quickly dissolve in the electrolyte and promote the electrolyte to enter the pores of the anode material. Meanwhile, during the lithium intercalation process, the dissolved carbon dioxide gas may reduce the decomposition rate of fluoroethylene carbonate (FEC) in the electrolyte, reduce the formation of a loose and irregular solid electrolyte interphase (SEI) on the surface of the anode material, increase the bonding effect between fluorine in the lithium fluoride SEI and lithium in the lithium silicon alloy, improve the interface stability of the lithium fluoride SEI, reduce the occurrence of side reactions, reduce the consumption of active lithium ions, and thus improving the capacity and initial coulomb efficiency of the anode material.
Following further describes the present disclosure with reference to the accompanying drawings and embodiments.
In order to better illustrate the technical solutions of the present disclosure, detailed description of embodiments of the present disclosure will be provided below in conjunction with the accompanying drawings.
It is to be made clear that the described embodiments are only some rather than all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts fall within the protection scope of the present disclosure.
The terms used in the embodiments of the present disclosure are merely for the purpose of describing particular embodiments but not intended to limit the present disclosure. The singular forms of “a”, “an” and “the” used in the embodiments of the present disclosure and the appended claims are also intended to include plural forms, unless clearly indicating others.
It should be understood that the term “and/or” used herein is merely an association relationship describing an associated object, and indicates that there may be three relationships, for example, A and/or B, and may indicate: A alone, both A and B, and B alone. In addition, the character “/” herein generally means an “or” relationship between the associated objects.
In a first aspect, as shown in
In the infrared spectrum of the anode material, there are a first absorption peak having a peak located at 2375±1 cm−1, denoted as A1, and a first valley located at 2394±1 cm−1, denoted as A0; and a second absorption peak having a peak located at 2919±1 cm−1, denoted as B1; and a second valley located at 2821±1 cm−1, denoted as B0.
The anode material has a carbon dioxide adsorption index P, wherein P=(A1−A0)/(B1−B0), and 0.25≤P≤0.70.
The anode materials provided by the present disclosure include a carbon substrate and an active material. The carbon substrate has pores, and the active material is distributed within the pores of the carbon substrate, allowing the anode material to maintain a high capacity; the carbon substrate may provide a certain volume space for the expansion of the active material, which is conducive to maintaining the structural stability of the anode material. The carbon substrate may also provide electron and ion transport pathways, improve lithium ion transport efficiency, and thus improving the initial coulomb efficiency of the anode material. Meanwhile, the pores of the carbon substrate contain carbon dioxide gas, which may quickly dissolve in the electrolyte and promote the electrolyte to enter the pores of the anode material. During the lithium intercalation process, the dissolved carbon dioxide gas may reduce the decomposition rate of fluoroethylene carbonate (FEC) in the electrolyte, reduce the formation of loose and irregular solid electrolyte interphase (SEI) on the surface of the anode material, increase the bonding effect between fluorine in the lithium fluoride SEI and lithium in the lithium silicon alloy, improve the interface stability of the lithium fluoride SEI, reduce the occurrence of side reactions, reduce the consumption of active lithium ions, and thus improving the capacity and initial coulomb efficiency of the anode material.
Specifically, the value of P may be 0.25, 0.26, 0.28, 0.30, 0.33, 0.35, 0.37, 0.40, 0.45, 0.50, 0.56, 0.60, 0.63, 0.66, 0.69, or 0.70, which is not limited here.
It may be understood that the P value may represent the ability of the anode material to adsorb CO2. The larger the P value, the stronger the ability of the anode material to adsorb CO2, and the more CO2 is adsorbed in the anode material. Meanwhile, the ability of the anode material to adsorb CO2 is related to the proportion of micro-pores in the anode material. The more micro-pores there are, the stronger the ability of the anode material to adsorb CO2.
When the P value is too high, it indicates that there is more CO2 adsorbed in the anode material, but Meanwhile, it also indicates that there are more micro-pores in the anode material, that is, the micro-pores inside the anode material particles are less filled with silicon, and the silicon content in the anode material is low, resulting in a lower capacity of the anode material. When the P value is too small, it indicates that there is less CO2 adsorbed in the anode material, and it also indicates that there are fewer micro-pores in the anode material, that is, the micro-pores inside the anode material particles are filled with more silicon, resulting in a higher silicon content in the anode material and an increase in its capacity; however, an increase in silicon content in the anode material will lead to a decrease in the conductivity of the material particles, which in turn will result in a decrease in the initial coulomb efficiency of the anode material.
It should be noted that the values of A1 to A0 represent the relative absorbance of carbon dioxide, while the values of B1 to B0 represent the relative absorbance of —CH2 (carbon substrate).
In some embodiments, the carbon substrate includes porous carbon.
In some embodiments, the active material includes nano-silicon, and the nano-silicon includes crystalline silicon and/or amorphous silicon.
In some embodiments, the carbon substrate has an average particle size ranging from 8 μm to 15 μm, which may specifically be 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, or 15 μm, etc., but it is not limited to the listed values. Other values not listed within this range are also applicable.
In some embodiments, a mass content of the carbon element in the anode material ranges from 49% to 51%, which may specifically be 49%, 49.3%, 49.5%, 49.6%, 49.7%, 50%, 50.2%, 50.6%, 50.7%, 50.9% or 51%, etc., and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, a mass content of the active material in the anode material ranges from 45% to 50%, which may specifically be 45%, 45.6%, 46%, 46.8%, 47.2%, 47.9%, 48%, 48.3%, 49%, 49.3% or 50% etc., and certainly may also be other values within the above range, which is not limited herein. It may be understood that controlling the mass content of the active material within the above range may effectively control the volume expansion of the anode material and the capacity of the anode material at the same time; meanwhile, since the active material preferentially occupies micro-pores in the preparation process of the anode material, the mass content of the active material is controlled within the above range, which may ensure that a certain number of micro-pores are reserved in the anode material particles, which is beneficial to the adsorption of carbon dioxide gas by the anode material.
In some embodiments, the anode material contains oxygen element, and a mass content of the oxygen element in the anode material ranges from 1.0% to 4.0%, which may specifically be 1.0%, 1.2%, 1.3%, 1.5%, 2%, 2.1%, 2.3%, 2.5%, 3%, 3.2%, 3.5%, 4%, etc., and certainly may also be other values within the above range, which is not limited herein. In the present disclosure, controlling the mass content of oxygen element in the anode material within the above range is beneficial to improving the specific capacity of the anode material and reducing the formation of inactive silica.
In some embodiments, the anode material has an average particle size ranging from 0.8 μm to 25 μm, which may specifically be 0.8 μm, 1 μm, 2 μm, 3 μm, 3.5 μm, 4 μm, 8 μm, 10 μm, 15 μm, 20 μm, 21 μm, 23 μm, 24 μm or 25 μm, etc., and certainly may also be other values within the above range, which is not limited herein. In the present disclosure, the average particle size of the anode material is controlled within the above range, which is beneficial to improving the cycling performance of the lithium ion battery made of the anode material.
In some embodiments, the anode material has pores, and the pores in the anode material include micro-pores, meso-pores and macro-pores.
In some embodiments, the pores of the anode material has an average pore size ranging from 1 nm to 10 nm, which may specifically be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm, etc., and certainly may also be other values within the above range, which is not limited herein. Controlling the average pore size of the anode material within the above range is beneficial to the adsorption of CO2 by the anode material.
In some embodiments, the total pore volume of the anode material is 0.001 cm3/g to 0.20 cm3/g, which may specifically be 0.001 cm3/g, 0.005 cm3/g, 0.01 cm3/g, 0.02 cm3/g, 0.05 cm3/g, 0.08 cm3/g, 0.12 cm3/g, 0.15 cm3/g, 0.18 cm3/g or 0.20 cm3/g etc., which is not limited here.
In some embodiments, the anode material has pores, the pores in the anode material include micro-pores, and a pore volume of the micro-pore has a volume proportion of 30% to 65%, which may specifically be 30%, 35%, 40%, 50%, 55%, 58%, 60%, 62%, 63%, or 65% of a total pore volume of all pores, but is not limited to the recited values, and other unlisted values within this range are also applicable.
In some embodiments, the anode material has pores, and the pores in the anode material include meso-pores, and a pore volume of the meso-pore has a volume proportion of 35% to 70%, which may specifically be 35%, 36%, 37%, 38%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%, etc. of a total pore volume of all pores, and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, the anode material has pores, and the pores in the anode material include macro-pore, and a pore volume of the macro-pore has a volume proportion of 0% to 5%, which may specifically be 0%, 0.5%, 0.8%, 1%, 1.5%, 2.1%, 3.2%, 3.8%, 4.4%, 4.7% or 5%, etc. of a total pore volume of all pores, and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, the specific surface area of the anode material is 1 m2/g to 300 m2/g, which may specifically be 1 m2/g, 5 m2/g, 10 m2/g, 20 m2/g, 50 m2/g, 100 m2/g, 125 m2/g, 130 m2/g, 150 m2/g, 200 m2/g, 250 m2/g, 300 m2/g, etc., and certainly may also be other values within the above range, which is not limited herein. Controlling the specific surface area of the anode material within the above range is beneficial to improving the cycling performance of the lithium ion battery made by the anode material.
In a second aspect, the present disclosure provides a method for preparing an anode material. The method includes following steps.
Step S100, a metal catalytic matrix is provided, and a carbon source gas is introduced to perform carbon deposition on the metal catalytic matrix to obtain a carbon substrate, the carbon substrate having pores.
Step S200, a reaction gas containing an active material is introduced, and vapor deposition is performed on the carbon substrate to obtain an anode material.
The present disclosure provides a preparation method of an anode material, firstly, the carbon source gas is deposited on the metal catalytic matrix to obtain a carbon substrate, the carbon substrate has pores, and the reaction gas containing the active material is introduced and vapor deposition is performed on the carbon substrate, in the processes of carbon deposition and vapor deposition, the metal catalytic matrix may improve deposition efficiency, accelerate the formation of the carbon substrate and the deposition of the active material, the active material may be fully filled into the pores of the carbon substrate, enable the prepared anode material to maintain a high capacity by vapor deposition; Meanwhile, the carbon substrate may provide a certain volume space for the expansion of the active material, which is conducive to maintaining the structural stability of the anode material, the carbon substrate may also provide electron and ion transport pathways, improve the lithium ion transport efficiency, and thus improving the initial coulomb efficiency of the anode material. In addition, the pores of the carbon substrate may adsorb carbon dioxide gas. The carbon dioxide gas adsorbed in the pores of the carbon substrate may quickly dissolve in the electrolyte and promote the electrolyte to enter the pores of the anode material. Meanwhile, during the lithium intercalation process, the dissolved carbon dioxide gas may reduce the decomposition rate of fluoroethylene carbonate (FEC) in the electrolyte, reduce the formation of a loose and irregular solid electrolyte interphase (SEI) on the surface of the anode material, increase the bonding effect between fluorine in the lithium fluoride SEI and lithium in the lithium silicon alloy, improve the interface stability of the lithium fluoride SEI, reduce the occurrence of side reactions, reduce the consumption of active lithium ions, and thus improving the capacity and initial coulomb efficiency of the anode material.
Step S100, a metal catalytic matrix is provided, and a carbon source gas is introduced to perform carbon deposition on the metal catalytic matrix to obtain a carbon substrate, the carbon substrate has pores.
In some embodiments, before introducing a carbon source gas to perform carbon deposition on the metal catalytic matrix, the method further includes: placing the metal catalytic matrix in an inert gas to perform air discharging treatment.
In some embodiments, a metal in the metal catalytic matrix includes at least one of iron, nickel, copper, gold, or an alloy.
In some embodiments, a metal in the metal catalytic matrix includes an alloy, the alloy includes at least one of an iron-cobalt alloy, a nickel-copper alloy, and an iron-nickel-copper alloy.
In some embodiments, the inert gas includes at least one of nitrogen, argon, and helium.
In some embodiments, the inert gas has a flow rate ranging from 20 sccm to 200 sccm, which may specifically be 20 sccm, 30 sccm, 50 sccm, 80 sccm, 100 sccm, 120 sccm, 150 sccm, 180 sccm or 200 sccm, etc., and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, the inert gas has an introduction time ranging from 0.5 h to 3 h, which may specifically be 0.5 h, 0.8 h, 1 h, 1.5 h, 1.8 h, 2 h, 2.3 h, 2.5 h or 3 h, etc., and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, the carbon source gas includes at least one of methane, acetylene, ethane, and propane.
In some embodiments, the carbon source gas has a flow rate ranging from 10 sccm to 80 sccm, which may specifically be 10 sccm, 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 70 sccm or 80 sccm, etc., and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, the carbon source gas has a introduction time ranging from 5 min to 30 min, which may specifically be 5 min, 8 min, 10 min, 15 min, 20 min, 22 min, 25 min, 28 min or 30 min, etc., and certainly may also be other values within the above range, which is not limited herein.
Step S200, a reaction gas containing an active material is introduced, and vapor deposition is performed on the carbon substrate to obtain an anode material.
In some embodiments, the reaction gas containing the active material includes a silicon source gas.
In some embodiments, the reaction gas containing the active material includes the silicon source gas, the silicon source gas includes silane and/or disilane.
In some embodiments, the reaction gas containing the active material includes a silicon source gas, and the silicon source gas has a flow rate ranging from 10 sccm to 80 sccm, which may specifically be 10 ccm, 20 ccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 70 sccm or 80 sccm, etc., and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, the reaction gas containing the active material includes a silicon source gas, and the silicon source gas has a introduction time ranging from 5 min to 30 min, which may specifically be 5 min, 8 min, 10 min, 15 min, 20 min, 22 min, 25 min, 28 min or 30 min, etc., and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, the carbon deposition and the silicon deposition has a temperature ranging from 600° C. to 700° C., which may specifically be 600° C., 620° C., 650° C., 660° C., 680° C., 690° C. or 700° C., which is not limited herein.
In some embodiments, the heating rate of carbon deposition and vapor deposition is between 1° C./min and 12° C./min, which may specifically be 1° C./min, 2° C./min, 5° C./min, 8° C./min, 9° C./min, 10° C./min, 11° C./min, or 12° C./min, etc., and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, the carbon deposition and the vapor deposition are performed in an inert gas.
In some embodiments, the carbon deposition and the vapor deposition are performed in the inert gas, the inert gas includes at least one of nitrogen, argon, and helium.
In some embodiments, the carbon deposition and the vapor deposition are performed in an inert gas, and the inert gas has a flow rate ranging from 5 sccm to 50 sccm, which may specifically be 5 sccm, 10 sccm, 15 sccm, 20 sccm, 25 sccm, 30 sccm, 40 sccm, 50 sccm, etc., and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, after introducing the reaction gas containing the active material and performing vapor deposition on the carbon substrate, the method further includes: repeatedly introducing carbon source gas and reaction gas containing the active material for carbon deposition and vapor deposition for 4 h to 24 h, which may specifically be 4 h, 8 h, 10 h, 15 h, 18 h, 20 h, 22 h, or 25 h, etc., and certainly may also be other values within the above range, which is not limited herein.
In the present disclosure, repeated vapor deposition and carbon deposition may improve the deposition uniformity of the active material, enhance production efficiency, and reduce thermal energy waste during the preparation process.
In some embodiments, the method further includes separating the metal catalytic matrix from a deposition product, and then sequentially performing mechanical pulverization and airflow pulverization on the deposition product.
In some embodiments, the mechanical pulverization has a time ranging from 0.5 h to 3 h, which may specifically be 0.5 h, 0.8 h, 1 h, 1.5 h, 1.8 h, 2 h, 2.4 h, 2.6 h or 3 h, etc., and certainly may also be other values within the above range, which is not limited herein.
In some embodiments, the airflow pulverization has a time ranging from 0.5 h to 3 h, which may specifically be 0.5 h, 0.8 h, 1 h, 1.5 h, 1.8 h, 2 h, 2.4 h, 2.6 h or 3 h, etc., and certainly may also be other values within the above range, which is not limited herein.
In a third aspect, the present disclosure provides a lithium ion battery, the lithium ion battery includes the anode material according to the first aspect or the anode material prepared by the preparation method according to the second aspect.
(1) The iron metal catalytic plate was placed in a tube furnace, argon gas was introduced at a flow rate of 100 sccm for 0.5 hours to remove air from the tube furnace, then the flow rate of argon gas was adjusted to 10 sccm and the tube furnace was heated at a rate of 10° C./min; after the tube furnace was heated to 650° C., acetylene gas was introduced at a flow rate of 50 sccm for 20 minutes to perform carbon deposition on an iron metal catalytic plate, and then the acetylene gas was shut off to obtain a carbon substrate.
(2) Then, silane gas was introduced at a flow rate of 30 sccm for 20 minutes to perform vapor deposition on the carbon substrate, and then the silane gas was shut off.
(3) The steps (1) and (2) was repeated in sequence for 8 h, the iron metal catalytic plate was taken out after cooled to room temperature, the deposited product was separated from the iron metal catalytic plate, and the separated silicon-carbon material was sequentially subjected to mechanical pulverization and airflow pulverization for 1 h to obtain an anode material.
The anode material prepared in this Example includes a carbon substrate and an active material, the carbon substrate has pores, the active material is distributed in the pores of the carbon substrate, and the active material includes nano-silicon.
(1) The iron-nickel alloy metal catalytic plate was placed in a tube furnace, argon gas was introduced at a flow rate of 100 sccm for 0.5 hours to remove air from the tube furnace, then the flow rate of argon gas was adjusted to 10 sccm and the tube furnace was heated at a rate of 10° C./min; after the tube furnace was heated to 650° C., acetylene gas was introduced at a flow rate of 50 sccm for 20 minutes to perform carbon deposition on the iron-nickel alloy metal catalytic plate, and then the acetylene gas was shut off to obtain the carbon substrate.
(2) Then, silane gas was introduced at a flow rate of 35 sccm for 20 minutes to perform vapor deposition on the carbon substrate, and then the silane gas was shut off.
(3) The steps (1) and (2) was repeated in sequence for 8 h, the iron-nickel alloy metal catalytic plate was taken out after cooled to room temperature, the deposited product was separated from the iron-nickel alloy metal catalytic plate, and the separated silicon-carbon material was sequentially subjected to mechanical pulverization and airflow pulverization for 1 h to obtain the anode material.
The anode material prepared in this Example includes a carbon substrate and an active material, the carbon substrate has pores, the active material is distributed in the pores of the carbon substrate, and the active material includes nano-silicon.
(1) The nickel metal catalytic plate was placed in a tube furnace, argon gas was introduced at a flow rate of 200 sccm for 0.5 hours to remove air from the tube furnace, then the flow rate of argon gas was adjusted to 10 sccm and the tube furnace was heated at a rate of 10° C./min; after the tube furnace was heated to 650° C., acetylene gas was introduced at a flow rate of 50 sccm for 20 minutes to perform carbon deposition on the nickel metal catalytic plate, and then the acetylene gas was shut off to obtain the carbon substrate.
(2) Then, silane gas was introduced at a flow rate of 40 sccm for 20 minutes to perform vapor deposition on the carbon substrate, and then the silane gas was shut off.
(3) The steps (1) and (2) was repeated in sequence for 8 h, the nickel metal catalytic plate was taken out after cooled to room temperature, the deposited product was separated from the nickel metal catalytic plate, and the separated silicon-carbon material was sequentially subjected to mechanical pulverization and airflow pulverization for 1 h to obtain the anode material.
The anode material prepared in this Example includes a carbon substrate and an active material, the carbon substrate has pores, the active material is distributed in the pores of the carbon substrate, and the active material includes nano-silicon.
(1) The copper metal catalytic plate was placed in a tube furnace, argon gas was introduced at a flow rate of 200 sccm for 0.5 hours to remove air from the tube furnace, then the flow rate of argon gas was adjusted to 10 sccm and the tube furnace was heated at a rate of 10° C./min; after the tube furnace was heated to 650° C., acetylene gas was introduced at a flow rate of 50 sccm for 20 minutes to perform carbon deposition on the copper metal catalytic plate, and then the acetylene gas was shut off to obtain the carbon substrate.
(2) Then, silane gas was introduced at a flow rate of 45 sccm for 20 minutes to perform vapor deposition on the carbon substrate, and then the silane gas was shut off.
(3) The steps (1) and (2) was repeated in sequence for 8 h, the copper metal catalytic plate was taken out after cooled to room temperature, the deposited product was separated from the copper metal catalytic plate, and the separated silicon-carbon material was sequentially subjected to mechanical pulverization and airflow pulverization for 1 h to obtain the anode material.
The anode material prepared in this Example includes a carbon substrate and an active material, the carbon substrate has pores, the active material is distributed in the pores of the carbon substrate, and the active material includes nano-silicon.
Different from Example 1, in (2), then silane gas was introduced at a flow rate of 10 sccm for 30 min to perform vapor deposition on the carbon substrate, and then the silane gas was shut off.
The anode material prepared in this Example includes a carbon substrate and an active material, the carbon substrate has pores, the active material is distributed in the pores of the carbon substrate, and the active material includes nano-silicon.
Different from Example 1, in (2), then silane gas was introduced at a flow rate of 80 sccm for 5 min to perform vapor deposition on the carbon substrate, and then the silane gas was shut off. The anode material prepared in this Example includes a carbon substrate and an active material, the carbon substrate has pores, the active material is distributed in the pores of the carbon substrate, and the active material includes nano-silicon.
The anode material prepared in Example 1 was subjected to a multi-fluoropolymer plugging-pore experiment, and the specific steps were as follows.
(1) 30 g of the anode material prepared in Example 1, 1 g acrylic acid, 2 g polypropylene pyrrolidone and 300 mL n-butanol were placed in a reaction flask, and nitrogen was introduced after vacuumizing to ensure that the reaction environment was a nitrogen environment.
(2) The reaction flask was placed in a magnetic stirring water bath, stirred and heated to 65° C., then 1 g azodiisobutyronitrile and 20 mL cyclopentane were added and kept at constant temperature for 0.5 h, then 1 g hexafluorobutyl acrylate and 20 mL acetone were added and kept at constant temperature for 0.5 h, then the reaction solution was heated to 70° C. and kept at constant temperature for 6 h to end the reaction, and finally, subjected to suction filtration and ethanol washing to obtain the comparative anode material 1 with pores plugged by fluoropolymer.
Different from Comparative Example 1, (2) the reaction flask was placed in a magnetic stirring water bath, stirred and heated to 65° C., then 1 g azodiisobutyronitrile and 20 mL cyclopentane were added and kept at constant temperature for 0.5 h, then 2 g hexafluorobutyl acrylate and 20 mL acetone were added and kept at constant temperature for 0.5 h, then the reaction solution was heated to 70° C. and kept at constant temperature for 6 h to end the reaction, and finally, subjected to suction filtration and ethanol washing to obtain the comparative anode material 2 with pores plugged by fluoropolymer.
Different from Comparative Example 1, (2) the reaction flask was placed in a magnetic stirring water bath, stirred and heated to 65° C., then 2 g azodiisobutyronitrile and 20 mL cyclopentane were added and kept at constant temperature for 0.5 h, then 2 g hexafluorobutyl acrylate and 20 mL acetone were added and kept at constant temperature for 0.5 h, then the reaction solution was heated to 70° C. and kept at constant temperature for 6 h to end the reaction, and finally, subjected to suction filtration and ethanol washing to obtain the comparative anode material 3 with pores plugged by fluoropolymer.
A silicon-free porous carbon preparation experiment was performed on the silicon-carbon anode active material prepared in Example 1, the specific steps are as follows:
30 g of the anode material prepared in Example 1 was placed in 250 mL of a hydrofluoric acid solution with a mass fraction of 20%, soaked for 12 h, and then subjected to suction filtration and pure water washing to obtain a comparative porous carbon anode active material 4.
A carbon growth plugging-pore experiment was performed on the silicon-carbon anode active material prepared in Example 1, the specific steps are as follows:
(1) 30 g of the anode material prepared in Example 1 was placed into a tube furnace and argon was introduced at a flow rate of 100 sccm for 0.5 h to remove air. Then the flow rate of argon was adjusted to 10 sccm, and the tube furnace was heated at a heating rate of 10° C./min to 650° C.
(2) Then acetylene gas was introduced at a flow rate of 10 sccm for 10 min, the acetylene gas was shut off, and the temperature was naturally reduced to room temperature to obtain a comparative anode material 5.
Different from Comparative Example 5, (2) then acetylene gas was introduced at a flow rate of 10 sccm for 20 min, the acetylene gas was shut off, and the temperature was naturally reduced to room temperature to obtain a comparative anode material 6.
Different from Comparative Example 5, (2) then acetylene gas was introduced at a flow rate of 10 sccm for 30 min, the acetylene gas was shut off, and the temperature was naturally reduced to room temperature to obtain a comparative anode material 7.
Different from Comparative Example 5, (2) then acetylene gas was introduced at a flow rate of 10 sccm for 40 min, the acetylene gas was shut off, and the temperature was naturally reduced to room temperature to obtain a comparative anode material 8.
German Bruker/German Eltra infrared carbon sulfur analyzer G4 ICARUS HF/CS-i was used, the sample was burned in a high-temperature oxygen rich state, and the carbon elements contained in it were oxidized to carbon dioxide, which entered the infrared detector with the carrier gas. The mass content of carbon elements was calculated quantitatively by analyzing the changes in the infrared absorption wavelength intensity of the carbon dioxide signal.
A sample was dried overnight and placed in a corundum crucible. The crucible was placed in a 1200° C. muffle furnace (Nanyang Xinyu SA2-9-17TP) for 480 minutes to complete the combustion of carbon and the oxidation reaction of silicon or silicon monoxide to silica; during the process, the weight of the crucible m0, the weight of the sample m1, the total weight of the crucible and product after burning m2 were recorded, and the silicon content according to following formula was calculated: Si %=(m2−m0)/m1× 28.09/60.09×100%.
German Friedel Crafts Oxygen Nitrogen Hydrogen Analyzer ONH 2000 was used, the principle is that the sample is wrapped in a fluxing agent and melted in an inert atmosphere, and the oxygen elements contained in it are reduced to carbon dioxide by carbon in a graphite crucible. The generated carbon dioxide entered the infrared detector with the carrier gas, and the change in the infrared signal of carbon dioxide was quantitatively counted to calculate the mass content of oxygen elements.
Malvern laser particle size analyzer MS3000 was used, based on the principle that the scattered light intensity distribution generated by particles in various directions depends on the size of the particles, large particles have small scattering angles, and small particles have large scattering angles. Therefore, the particle size distribution may be obtained by using the scattered light intensity distribution of laser diffraction.
Thermo Scientific iN10 Fourier transform infrared spectrometer from the United States was used to test a small amount of test samples and KBr tablets to obtain their infrared absorption spectra.
Physical and Chemical Union iPore620 pore size tester and BET pore size distribution testing method were used, the isothermal adsorption characteristic curve of nitrogen gas was used to obtain the pore size distribution data of the materials through DFT simulation analysis, and then the average pore size, total pore volume, and BET specific surface area of the materials were obtained.
The anode materials prepared in Examples 1 to 6 and Comparative Examples 1 to 8, conductive carbon black (super P), and LA133 were mixed in a ratio of 70:15:15 into a slurry and evenly coat it onto copper foil, then dried, and the anode sheet was prepared. The metal lithium sheets were used as counter electrodes and assembled into a button cell in an argon-filled glove box, and tested for charging capacity and initial coulombic efficiency on a Blue Power Battery Test Cabinet M340A.
The above test data are detailed in Table 1 and Table 2.
According to the test data in Tables 1 and 2, it may be seen that the anode materials prepared in Examples 1 to 6 include a carbon substrate and an active material. The carbon substrate has pores, and the active material is distributed within the pores of the carbon substrate, allowing the anode material to maintain a high capacity; the carbon substrate may provide a certain volume space for the expansion of the active material, which is conducive to maintaining the structural stability of the anode material. The carbon substrate may also provide electron and ion transport pathways, improve lithium ion transport efficiency, and thus improving the initial coulomb efficiency of the anode material. Meanwhile, the pores of the carbon substrate contain CO2, which may quickly dissolve in the electrolyte and promote the electrolyte to enter the pores of the anode material. Meanwhile, during the lithium intercalation process, the dissolved CO2 may reduce the decomposition rate of fluoroethylene carbonate (FEC), reduce the formation of loose and irregular solid electrolyte interphases (SEI), increase the bonding effect between fluorine in the lithium fluoride SEI and lithium in the lithium silicon alloy, improve the interface stability of the lithium fluoride SEI, reduce the occurrence of side reactions, reduce the consumption of active lithium ions, and thus improving the capacity and initial coulomb efficiency of the anode material.
The above are only preferred Examples of the present disclosure and are not intended to limit the present disclosure, and it should be noted herein that any modifications, equivalent substitutions, improvements, and the like made within the spirit and principle of the present disclosure shall fall within the protection scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202311407790.0 | Oct 2023 | CN | national |
The present application is a continuation of International Patent Application No: PCT/CN2024/102003 filed on Jun. 27, 2024, which claims priority to Chinese Patent Application No. 202311407790.0 filed on Oct. 26, 2023, the disclosure each of which is hereby incorporated by reference in their entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2024/102003 | Jun 2024 | WO |
| Child | 19020973 | US |
