CN115692724A - Carbon-coated foil and preparation method and application thereof - Google Patents
Carbon-coated foil and preparation method and application thereof Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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Abstract
The invention provides a carbon-coated foil material and a preparation method and application thereof, wherein the carbon-coated foil material comprises a foil piece and a carbon-coated layer on at least one side surface of the foil piece, and the carbon-coated layer comprises a porous carbon material; the porosity of the carbon-coated layer is greater on the side remote from the foil than on the side close to the foil. According to the invention, the carbon coating layer is set to be a special structure with different porosities, so that from the perspective of the porosity of the coating layer, the wettability of the electrolyte is ensured, and the utilization rate of the electrolyte is improved, therefore, the limitation of lithium ions in the diffusion of the pores in the porous electrode is improved, so that the electrode not only has good conductivity and low contact resistance, but also obviously improves the multiplying power performance.
Description
Technical Field
The invention belongs to the technical field of batteries, and relates to a carbon-coated foil as well as a preparation method and application thereof.
Background
Market development puts higher requirements on the energy density and rate capability of the power lithium ion battery. On the basis of the prior art, the electrode is thickened and rolled, and the volume ratio of the active substance is improved by reducing the porosity of the electrode. Although the energy density of the battery can be increased, it causes a loss of the discharge capacity of the battery at a large rate.
Because the lithium ion battery is charged and discharged, li + Diffusion between the positive and negative electrodes takes three processes: 1) Solid phase diffusion inside the active material particles; 2) Charge exchange at the electrode/electrolyte interface; 3) Diffusion inside the porous electrode, each step possibly becoming a limiting step of the battery charge-discharge rate; research shows that the LFP/graphite system battery adopting the thin electrode design has better rate performance, but the rate performance is greatly influenced after the electrode is thickened, which also shows that Li + The diffusion process of pores in the thick porous electrode is an important limiting link of the rate capability of the lithium ion battery, so that the influence of the thickened electrode on the rate capability is considered, and the foil of the electrode needs to be further improved to solve the limitation of the charge and discharge rate of the battery.
The conventional foil is a smooth foil, and if a layer of conductive material (such as graphite, CNT or graphene) is coated on the surface of an aluminum foil or a copper foil, the coating thickness is between 1 and 2 mu m, the foil is called a carbon-coated foil. Compared with a smooth foil, the carbon-coated foil can reduce the ohmic impedance of the electrode, enhance the bonding strength of the positive and negative electrode slurry and the current collector, and when a pole piece resistance tester is used for measuring the resistance of the positive pole piece of the same surface density and different current collectors, the contact resistance of the positive pole piece of the carbon-coated aluminum foil is 0.1-1.0 omega cm 2 The contact resistance of the positive plate obtained by using the smooth aluminum foil is 30-50 omega cm 2 The contact resistance of the positive plate using the carbon-coated aluminum foil is reduced by at least one order of magnitude, and the DCR is also reduced from 120m omega to 30m omega. In addition, compared with the conventional foil, the carbon-coated foil has good conductivity due to the coated carbon layer, so that the use amount of a conductive agent and a binder can be reduced, and the cycle life of the battery is prolonged.
For example, CN 109888296A discloses a method for preparing a carbon-coated current collector for a positive electrode of a lithium ion battery, which comprises the following steps: placing a current collector in an organic solvent containing nano carbon powder and nano titanium powder, and carrying out ultrasonic vibration cleaning; placing the treated current collector in a vacuum deposition chamber, introducing a reaction carbon source gas under certain pressure, and performing pre-nucleation treatment on the surface of the current collector; the pressure in the vacuum deposition chamber is increased, the flow of the reactive carbon source gas is adjusted, and the growth of crystal nuclei on the surface of the current collector to form a film is promoted; compared with the current collector prepared by the traditional method, the method has the advantages that the peeling strength is higher, the risk of peeling the coating is reduced, the service life of the battery is prolonged, but the improvement on the comprehensive performance of the battery is limited, particularly the multiplying power performance cannot be improved by the improvement of the carbon-coated current collector.
Based on above research, need provide a scribble carbon foil, scribble carbon foil can not only promote the electric conductivity of electrode, reduce contact resistance, can also improve battery multiplying power performance, solve the limited problem of battery charge-discharge rate.
Disclosure of Invention
The invention aims to provide a carbon-coated foil and a preparation method and application thereof, wherein the carbon-coated foil not only has the advantages of the conventional carbon-coated foil and enables an electrode to have good conductivity and low contact resistance, but also improves the porosity of the electrode and the limitation of lithium ion diffusion in the pores of a porous electrode through the special structure of a carbon-coated layer, and enables the battery to have excellent rate performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a carbon-coated foil, which comprises a foil and a carbon-coated layer on at least one side surface of the foil, wherein the carbon-coated layer comprises a porous carbon material;
the porosity of the carbon-coated layer is greater on the side away from the foil than on the side adjacent to the foil.
The carbon-coated foil disclosed by the invention improves the problem that lithium ions are limited to diffuse in the internal pores of the porous electrode from the perspective of the porosity of the coating, and particularly, the carbon-coated layer is arranged into a special structure with different porosities, wherein the porosity of the top part far away from one side of the foil is larger, so that the electrolyte can diffuse inwards from the top part, the electrolyte can be fully infiltrated, the porosity of the bottom part near one side of the foil is smaller than the porosity of the top part, and on the premise of ensuring the full contact between the electrode material and the electrolyte, the problems that the electrolyte is excessively permeated from the bottom part and the utilization rate of the electrolyte is reduced are avoided, so that the rate performance of the electrode is optimized.
In addition, the carbon-coated layer comprises a porous carbon material, the porous carbon material refers to a carbon material with different pore structures, and can be subdivided into a disordered porous carbon material and an ordered porous carbon material according to the structural characteristics of the porous carbon material, the disordered porous carbon material has irregular pore channel shapes, and the pore size distribution range is wide; the ordered porous carbon material has the advantages of regular pore channel arrangement, pore channel shape, controllable pore diameter and narrow pore diameter distribution range; in addition, the porous carbon material not only has the properties of carbon materials such as high chemical stability, good conductivity and low price, but also has the advantages of adjustable pore diameter, pore channel and morphology and the like, and can be used for constructing a special pore structure of the invention, so that the carbon-coated foil material can improve the conductivity of the electrode, reduce the contact resistance and improve the rate capability of the battery.
Preferably, the morphology of the porous carbon material comprises a two-dimensional hexagonal morphology.
The porous carbon material is an ordered porous carbon material, has a specific shape of a two-dimensional hexagon, has the advantages of regular pore channel arrangement, pore channel shape, controllable pore diameter and narrow pore diameter distribution range compared with a disordered porous carbon material, and is a porous carbon material with a two-dimensional hexagonal structure, low curvature and high order compared with a spherical porous carbon material and the like, wherein electrons can rapidly pass through a current collector and an active substance due to the low curvature, so that the rate capability of a battery can be further improved.
Preferably, the carbon-coated layer has a gradient porosity.
In order to obtain the effect that the electrode can be fully infiltrated and the utilization rate of the electrolyte can not be reduced, the porosity of the carbon-coated layer is set to be the gradient porosity which is reduced in sequence from the outside far away from the foil to the inside near the foil.
Preferably, the porosity of the coated layer is from 40% to 60%, and can be, for example, 40%, 45%, 50%, 55%, or 60%, but is not limited to the recited values, and other unrecited values within the numerical range are equally applicable.
Preferably, the carbon-coated layer has a thickness of 1 to 2 μm, and may be, for example, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm or 2 μm, but is not limited to the values recited, and other values not recited within the range of values are equally applicable.
Preferably, the foil has a thickness of 4-16 μm, which may be, for example, 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm or 16 μm, but is not limited to the values recited, and other values not recited in the range of values are equally applicable.
Preferably, the foil comprises aluminum foil and/or copper foil.
In a second aspect, the present invention provides a method of making a carbon-coated foil material as described in the first aspect, the method comprising the steps of:
and arranging a porous carbon material on at least one side surface of the foil, then immersing the foil into an etching solution, and sintering the immersed foil to obtain the carbon-coated foil.
The structure of the carbon-coated layer, wherein the porosity of the side, far away from the foil, of the carbon-coated layer is larger than the porosity of the side, close to the foil, of the carbon-coated layer is obtained through etching, the carbon-coated layer is sintered after being immersed in etching liquid, the etching liquid infiltrated in the porous carbon material can etch the surface of the material at high temperature, so that a top hole channel of the carbon-coated layer is increased, the porosity of the side, far away from the foil, is improved, and a special structure with small porosity at the bottom and large porosity at the top is formed.
Preferably, the method of disposing the porous carbon material on the foil comprises: the porous carbon material is coated or sprayed on the surface of the foil by slurry obtained by mixing the porous carbon material with water.
Preferably, the concentration of the etching solution is 3.5-6.5mol/L, for example, 3.5mol/L, 4mol/L, 4.5mol/L, 5mol/L, 5.5mol/L, 6.0mol/L or 6.5mol/L, but is not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, the etching solution comprises any one of KOH, naOH, or HF.
When KOH is adopted for etching, the following reactions can occur: 4KOH + -CH 2 →K 2 CO 3 +K 2 O+3H 2 ，K 2 CO 3 +2-C- → 2K +3CO, the carbon element participating in the reaction becomes CO gas and escapes, a new pore channel appears at the position of the carbon element, so that the porosity of the carbon-coated layer is controllable, and the pore channel is adjustable.
The sintering temperature and the concentration of the etching liquid can influence the etching effect, so that the porosity of the carbon-coated layer is influenced, and therefore, the sintering temperature and the concentration of the etching liquid are set within a reasonable range, if the etching temperature is too high, the time is too long or the concentration of the etching liquid is too high, the pore channels and the pore diameters of the carbon-coated layer are too large, the specific surface area of the material of the carbon-coated layer is too large, the adsorbed electrolyte is too large, the too much electrolyte is concentrated in the carbon-coated layer of the foil, the infiltration of the active material is not facilitated, and the electrolyte can react with the coating material to damage the structure of the coating material, so that the cohesiveness and the conductivity of the active material and the foil are reduced, and the multiplying power performance of the battery is deteriorated; when the etching temperature is too low, the etching time is too short or the concentration of the etching liquid is too low, the structure of the carbon-coated layer cannot be effectively constructed, the electrolyte cannot be fully infiltrated, and the technical effect that too much electrolyte is infiltrated into the bottom is avoided.
Preferably, the sintering is carried out in a protective atmosphere at a temperature of 500-700 ℃, for example 500 ℃, 550 ℃,600 ℃, 650 ℃ or 700 ℃, but not limited to the recited values, and other values not recited within the numerical range are equally applicable.
Preferably, the sintering time is 1 to 3 hours, and may be, for example, 1 hour, 1.25 hours, 1.5 hours, 1.75 hours, 2 hours, 2.25 hours, 2.5 hours, 2.75 hours or 3 hours, but is not limited to the recited values, and other values not recited in the numerical ranges are also applicable.
Preferably, the protective atmosphere comprises any one of argon, helium, neon or krypton, or a combination of at least two thereof, with typical, but non-limiting combinations including argon and helium, or neon and krypton.
Preferably, the method for preparing the porous carbon material comprises the following steps:
mixing, heating and calcining a phenol source, an organic source, a template agent, a catalyst and a pore-expanding agent to obtain the porous carbon material;
the organic source comprises an aldehyde source and/or an amine source.
The ordered porous carbon material is synthesized by an organic-organic self-assembly method, wherein phenolic resin generated by a phenol source and an organic source is used as a carbon source precursor, hydrogen bonds or coulomb force interaction exists between the carbon source precursor and a template agent, and then the template agent is removed at high temperature and the precursor is carbonized to remove impurities under the action of a pore-expanding agent, so that the ordered porous carbon material with a specific two-dimensional hexagonal structure can be obtained; namely, the specific two-dimensional hexagonal porous carbon material can be obtained only by matching the phenol source, the organic source, the template agent, the catalyst and the pore-expanding agent.
Preferably, the mass ratio of the phenol source, the organic source, the templating agent, the catalyst and the pore-expanding agent is (4-7): 0.5-1.5): 1 (0.5-3): 1-3, for example, the ratio can be 6.
The pore diameter of the porous carbon material can be increased along with the increase of the amount of the pore-expanding agent, and the pore diameter of the porous carbon material is not changed after the pore-expanding agent is added to a certain extent, so that the pore diameter and the porosity of the porous carbon material are influenced by the content of the pore-expanding agent.
Preferably, the pore-expanding agent comprises m-trimethylbenzene and/or PVB (polyvinyl butyral).
Preferably, the templating agent comprises any one or a combination of at least two of P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer), F127 (polymer of propylene oxide and ethylene oxide) or F108 (polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer), typical but non-limiting combinations include combinations of P123 and F127, F127 or F108.
Preferably, the catalyst comprises L-lysine.
Preferably, the organic source comprises any one of, or a combination of at least two of, hexamethylenetetramine, formaldehyde or melamine, typical but non-limiting combinations including hexamethylenetetramine and formaldehyde, or hexamethylenetetramine and melamine.
Preferably, the phenol source comprises hydroquinone and/or resorcinol.
Preferably, the heating is carried out at a temperature of 65 to 85 ℃, for example 65 ℃,70 ℃,75 ℃, 80 ℃ or 85 ℃ for a time of 24 to 35 hours, for example 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours or 35 hours, but not limited to the recited values, and other values not recited in the range of values are equally applicable
Preferably, the heating is performed in an autoclave.
Preferably, the calcination temperature is above 800 ℃, for example 800 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃, 1050 ℃ or 1100 ℃, but not limited to the recited values, and other values not recited in the numerical range are equally applicable
As a preferred technical scheme of the preparation method of the carbon-coated foil, the preparation method comprises the following steps:
(1) Mixing a phenol source, an organic source, a template agent, a catalyst and a pore-expanding agent according to the mass ratio of (4-7) to (0.5-1.5) to (1) (0.5-3) to (1-3), heating at 65-85 ℃ for 24-35h and calcining at above 800 ℃ to obtain the porous carbon material;
the pore-expanding agent comprises m-trimethylbenzene and/or PVB, the template agent comprises any one of P123, F127 or F108 or a combination of at least two of the P123, the F127 and the F108, and the catalyst comprises L-lysine;
(2) Arranging the porous carbon material in the step (1) on at least one side surface of a foil, then immersing the foil into etching liquid, and sintering the immersed foil for 1-3 hours at the temperature of 500-700 ℃ in a protective atmosphere to obtain the carbon-coated foil;
the concentration of the etching liquid is 3.5-6.5mol/L.
In a third aspect, the present invention provides a lithium ion battery comprising a carbon-coated foil as described in the first aspect.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the invention, the carbon coating layer is set to be of a special structure, the porosity of the top part far away from the foil is larger, and the porosity of the bottom part near the foil is smaller than that of the top part, so that on the premise of ensuring full contact between an electrode material and electrolyte, the problems of excessive electrolyte permeation from the bottom and reduction of the utilization rate of the electrolyte can be avoided, and the rate performance of the battery is optimized;
(2) The porous carbon material adopted by the carbon-coated layer is a two-dimensional hexagonal ordered porous carbon material, not only has the properties of the carbon material such as high chemical stability, good conductivity, low price and the like, but also has the advantages of regular pore channel arrangement, controllable pore channel shape, controllable pore diameter and narrow pore diameter distribution range, and compared with the spherical porous carbon material and the like, the porous carbon material with the two-dimensional hexagonal structure has low curvature and high order, and can enable electrons to rapidly pass through between a foil material and an active substance, so that the rate capability of the battery can be further improved;
(3) According to the invention, the carbon-coated foil is etched to obtain a structure that the porosity of the carbon-coated layer far away from the foil is larger than that of the carbon-coated layer near the foil, and then the specific ordered porous carbon material is synthesized by matching an organic-organic self-assembly method, wherein phenolic resin generated by a phenol source and an organic source is used as a carbon source precursor, hydrogen bonds or coulomb force interaction exists between the carbon source precursor and a template agent, and then under the action of a pore-expanding agent, the template agent is removed at high temperature and the precursor is carbonized, so that the ordered porous carbon material with a specific two-dimensional hexagonal structure can be obtained, the porous carbon material can be matched with the carbon-coated layer structure, and the effect of improving the multiplying power performance of the battery is realized.
Drawings
FIG. 1 is a schematic structural view of a porous carbon material described in example 1 of the present invention.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitation of the present invention.
Example 1
The embodiment provides a carbon-coated foil, which includes a foil and carbon-coated layers on two side surfaces of the foil, wherein the carbon-coated layers include a porous carbon material with a two-dimensional hexagonal morphology, and a structural schematic diagram of the porous carbon material is shown in fig. 1;
the porosity of the carbon-coated layer is 50%; the porosity of one side of the carbon-coated layer, which is far away from the foil, is greater than that of one side of the carbon-coated layer, which is close to the foil, and the porosity is gradually reduced from one side of the carbon-coated layer, which is far away from the foil, to one side of the carbon-coated layer, which is close to the foil;
the foil is an aluminum foil with the thickness of 8 mu m, and the carbon-coated layer is 1.5 mu m;
the preparation method of the carbon-coated foil comprises the following steps:
(1) Mixing hydroquinone, hexamethylenetetramine, P123, L-lysine and m-trimethylbenzene according to the mass ratio of 1;
(2) Arranging the porous carbon material in the step (1) on two sides of a foil, then immersing the foil into a KOH solution, and sintering the immersed foil for 2 hours at the temperature of 600 ℃ in an argon atmosphere to obtain the carbon-coated foil;
the concentration of the KOH solution is 4mol/L.
Example 2
The embodiment provides a carbon-coated foil, which comprises a foil and carbon-coated layers on the surfaces of two sides of the foil, wherein the carbon-coated layers comprise a porous carbon material with a two-dimensional hexagonal morphology;
the porosity of the carbon-coated layer is 60%; the porosity of one side of the carbon-coated layer, which is far away from the foil, is greater than that of one side of the carbon-coated layer, which is close to the foil, and the porosity is gradually reduced from one side of the carbon-coated layer, which is far away from the foil, to the other side of the carbon-coated layer, which is close to the foil;
the foil is an aluminum foil with the thickness of 6 mu m, and the carbon-coated layer is 1 mu m;
the preparation method of the carbon-coated foil comprises the following steps:
(1) Mixing resorcinol, formaldehyde, F127, L-lysine and PVB according to a mass ratio of 4.5;
(2) Arranging the porous carbon material in the step (1) on two sides of a foil, then immersing the foil into HF solution, and sintering the immersed foil for 1h at 700 ℃ in a helium atmosphere to obtain the carbon-coated foil;
the concentration of the HF solution is 6mol/L.
Example 3
The embodiment provides a carbon-coated foil, which comprises a foil and carbon-coated layers on the surfaces of two sides of the foil, wherein the carbon-coated layers comprise a porous carbon material with a two-dimensional hexagonal morphology;
the porosity of the carbon-coated layer is 40%; the porosity of one side of the carbon-coated layer, which is far away from the foil, is greater than that of one side of the carbon-coated layer, which is close to the foil, and the porosity is gradually reduced from one side of the carbon-coated layer, which is far away from the foil, to the other side of the carbon-coated layer, which is close to the foil;
the foil is a copper foil with the thickness of 16 mu m, and the thickness of the carbon-coated layer is 2 mu m;
the preparation method of the carbon-coated foil comprises the following steps:
(1) Mixing hydroquinone, melamine, F108, L-lysine and m-trimethylbenzene according to the mass ratio of 7.5;
(2) Arranging the porous carbon material in the step (1) on two sides of a foil, then immersing the foil into a KOH solution, and sintering the immersed foil for 3 hours at the temperature of 500 ℃ in an argon atmosphere to obtain the carbon-coated foil;
the concentration of the KOH solution is 3.5mol/L.
Example 4
This example provides a carbon-coated foil material that is the same as in example 1, except that the sintering temperature in step (2) was 450 ℃ in the preparation process, and the carbon-coated foil material was changed accordingly.
Example 5
This example provides a carbon-coated foil material that is the same as in example 1, except that the sintering temperature in step (2) was 550 ℃ in the preparation process, and the carbon-coated foil material was changed accordingly.
Example 6
This example provides a carbon-coated foil, which is the same as example 1 except that the KOH solution of step (2) is at a concentration of 3mol/L in the preparation method, and the carbon-coated foil is changed accordingly.
Example 7
This example provides a carbon-coated foil, which is the same as example 1 except that the KOH solution of step (2) is 7mol/L, and the concentration of the carbon-coated foil is changed accordingly in the preparation method.
Example 8
This example provides a carbon-coated foil, which is the same as in example 1 except that in the preparation method, the mass ratio of hydroquinone, hexamethylenetetramine, P123, L-lysine and m-trimethylbenzene in step (1) is 6.
Example 9
This example provides a carbon-coated foil, which is the same as in example 1, except that in the preparation method, the mass ratio of hydroquinone, hexamethylenetetramine, P123, L-lysine and m-trimethylbenzene in step (1) is 6.
Example 10
This example provides a carbon-coated foil material that is the same as in example 1 except that in the method of preparation, m-trimethylbenzene was not added in step (1) to change the carbon-coated foil material accordingly.
Example 11
The embodiment provides a carbon-coated foil, and the carbon-coated foil is the same as that in embodiment 1 except that in a carbon-coated layer, the shape of a porous carbon material is spherical;
the preparation method of the spherical porous carbon material comprises the following steps:
mixing hydroquinone and hexamethylenetetramine according to the mass ratio of 6.
Comparative example 1
This comparative example provides a carbon-coated foil material that was the same as in example 1 except that the porosity of the carbon-coated layer on the side away from the foil was the same as the porosity on the side near the foil;
the carbon-coated foil was produced in the same manner as in example 1, except that the step (2) was not immersed in a KOH solution, but was directly sintered after installation.
Comparative example 2
This comparative example provides a foil which is the same as example 1 except that no carbon-coated layer is provided.
Coating the positive electrode active layer or the negative electrode active layer slurry on the foils of the above examples and comparative examples to prepare a positive electrode plate and a negative electrode plate, and assembling the positive electrode plate and the negative electrode plate, the PE diaphragm and the lithium hexafluorophosphate electrolyte to form the lithium ion battery, wherein the active material of the positive electrode plate is LFP/NCM/LCO, and the active material of the negative electrode plate is graphite material/silicon-based material; the assembled lithium ion battery tests the rate capability and the DCR, and the rate capability test conditions are as follows: the discharge capacity retention rate of the material is tested under the conditions of 1C/1C, 1C/3C and 1C/5C, and the test conditions of DCR are as follows: charging to a specified SOC at a constant current of 0.33C, standing for 1h, charging and discharging at 1C for 10s (recording interval of 1 s), and standing for 10min; DCR formula: charge/discharge end voltage-charge/discharge start voltage |/1c 1000.
The test results are shown in table 1:
TABLE 1
As can be seen from table 1:
the carbon-coated foil provided by the invention can reduce the internal resistance of the battery, can also improve the rate capability of the battery, and improves the limit of lithium ion diffusion in the internal pores of the porous electrode; from example 1 and examples 4 to 11, it is clear that: the sintering temperature and the concentration of the etching solution in the step (2) can influence the etching effect, so that the porosity of the carbon-coated layer is influenced; the amount of the pore-expanding agent is within a reasonable range, so that all raw materials in the porous carbon material are matched to achieve the purpose of regulating and controlling the pore diameter and the porosity; when the morphology of the porous carbon material is changed, the performance of the battery is also influenced, and electrons can rapidly pass through a current collector and an active substance due to the two-dimensional hexagonal morphology, so that the rate capability of the battery can be further improved; meanwhile, as can be seen from the example 1 and the comparative examples 1 to 2, the rate performance of the battery can be obviously improved and the internal resistance can be reduced compared with the empty foil and the conventional carbon-coated current collector.
In conclusion, the carbon-coated foil material and the preparation method and application thereof provided by the invention have the advantages of the conventional carbon-coated foil material, so that the electrode has good conductivity and low contact resistance, and the porosity of the electrode is improved through the special structure of the carbon-coated layer, so that the limitation of lithium ion diffusion in the pores inside the porous electrode is improved, and the battery has excellent rate performance.
The above description is only for the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the protection scope and the disclosure of the present invention.
Claims (10)
1. The carbon-coated foil is characterized by comprising a foil and a carbon-coated layer on at least one side surface of the foil, wherein the carbon-coated layer comprises a porous carbon material;
the porosity of the carbon-coated layer is greater on the side away from the foil than on the side adjacent to the foil.
2. The carbon-coated foil of claim 1, wherein the morphology of the porous carbon material comprises a two-dimensional hexagonal morphology;
preferably, the carbon-coated layer has a gradient porosity;
preferably, the porosity of the carbon-coated layer is 40-60%;
preferably, the carbon-coated layer has a thickness of 1-2 μm.
3. A method of making the carbon-coated foil material of claim 1 or 2, wherein the method comprises the steps of:
and arranging a porous carbon material on at least one side surface of the foil, then immersing the foil into an etching solution, and sintering the immersed foil to obtain the carbon-coated foil.
4. The preparation method according to claim 3, wherein the concentration of the etching solution is 3.5-6.5mol/L;
preferably, the etching solution comprises any one of KOH, naOH or HF;
preferably, the sintering is carried out under a protective atmosphere at a temperature of 500-700 ℃;
preferably, the sintering time is 1-3h.
5. The production method according to claim 3 or 4, characterized in that the method for producing the porous carbon material comprises the steps of:
mixing, heating and calcining a phenol source, an organic source, a template agent, a catalyst and a pore-expanding agent to obtain the porous carbon material;
the organic source comprises an aldehyde source and/or an amine source.
6. The preparation method according to claim 5, wherein the mass ratio of the phenol source, the organic source, the template agent, the catalyst and the pore-enlarging agent is (4-7): 0.5-1.5): 1, (0.5-3): 1-3);
preferably, the pore-expanding agent comprises m-trimethylbenzene and/or PVB;
preferably, the templating agent comprises any one of P123, F127, or F108, or a combination of at least two thereof.
7. The production method according to claim 5 or 6, wherein the catalyst comprises L-lysine;
preferably, the organic source comprises any one of hexamethylenetetramine, formaldehyde or melamine or a combination of at least two thereof;
preferably, the phenol source comprises hydroquinone and/or resorcinol.
8. The method according to any one of claims 5 to 7, wherein the heating is carried out at a temperature of 65 to 85 ℃ for 24 to 35 hours;
preferably, the temperature of the calcination is above 800 ℃.
9. The production method according to any one of claims 3 to 8, characterized by comprising the steps of:
(1) Mixing a phenol source, an organic source, a template agent, a catalyst and a pore-expanding agent according to the mass ratio of (4-7) to (0.5-1.5) to (1) (0.5-3) to (1-3), heating at 65-85 ℃ for 24-35h and calcining at above 800 ℃ to obtain the porous carbon material;
the pore-expanding agent comprises m-trimethylbenzene and/or PVB, the template agent comprises any one of P123, F127 or F108 or a combination of at least two of the P123, the F127 and the F108, and the catalyst comprises L-lysine;
(2) Arranging the porous carbon material in the step (1) on at least one side surface of a foil, then immersing the foil into etching liquid, and sintering the immersed foil for 1-3 hours at the temperature of 500-700 ℃ in a protective atmosphere to obtain the carbon-coated foil;
the concentration of the etching liquid is 3.5-6.5mol/L.
10. A lithium-ion battery comprising the carbon-coated foil of claim 1 or 2.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116417621A (en) * | 2023-06-12 | 2023-07-11 | 广州方邦电子股份有限公司 | Composite foil, battery pole piece and battery |
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| CN102694150A (en) * | 2012-06-12 | 2012-09-26 | 宁德新能源科技有限公司 | Method for preparing lithium-ion secondary battery pole piece |
| CN113594414A (en) * | 2021-07-29 | 2021-11-02 | 溧阳紫宸新材料科技有限公司 | Organic porous skeleton cathode, preparation method thereof and battery |
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| US20120070741A1 (en) * | 2010-03-03 | 2012-03-22 | Amprius, Inc. | High capacity battery electrode structures |
| CN102694150A (en) * | 2012-06-12 | 2012-09-26 | 宁德新能源科技有限公司 | Method for preparing lithium-ion secondary battery pole piece |
| CN113594414A (en) * | 2021-07-29 | 2021-11-02 | 溧阳紫宸新材料科技有限公司 | Organic porous skeleton cathode, preparation method thereof and battery |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116417621A (en) * | 2023-06-12 | 2023-07-11 | 广州方邦电子股份有限公司 | Composite foil, battery pole piece and battery |
| CN116417621B (en) * | 2023-06-12 | 2023-09-05 | 广州方邦电子股份有限公司 | Composite foil, battery pole piece and battery |
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