CN104269515B - A kind of anode plate for lithium ionic cell and preparation method thereof, lithium ion battery - Google Patents
A kind of anode plate for lithium ionic cell and preparation method thereof, lithium ion battery Download PDFInfo
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- H—ELECTRICITY
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/134—Electrodes based on metals, Si or alloys
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- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
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- H—ELECTRICITY
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
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- H—ELECTRICITY
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
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- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention discloses a kind of anode plate for lithium ionic cell and preparation method thereof, lithium ion battery.The preparation method of the anode plate for lithium ionic cell of the present invention comprises the following steps: 1) compound concentration is the graphene oxide solution of 1～20mg/mL；2) preparation of nano silicon grain and the mixed solution of polymer；3) mode of electrostatic spraying is used, collector is fixed on the reception device, step 1 described in electrostatic spraying successively) prepare graphene oxide solution, described step 2) prepare mixed solution, respectively obtain one layer of graphene oxide film and one layer of silicon polymer thin film, be defined as AB layer；4) repeat to spray described graphene oxide solution and described mixed solution, form multiple AB Rotating fields the most on a current collector；5) collector that will be covered with multiple AB Rotating fields carries out carbonization process, prepares negative plate.The preparation method simple process of the present invention, cost is relatively low, and the volumetric properties of the negative plate prepared is preferable, can meet application demand.
Description
[technical field]
The present invention relates to lithium ion cell electrode sheet, particularly relate to a kind of anode plate for lithium ionic cell and preparation side thereof
Method.
[background technology]
Lithium ion battery is because it has higher energy density and the longest service life is widely used in portable electric
Subset, such as: notebook computer, mobile phone etc..The negative plate of the lithium ion battery of commercialization at present mainly uses graphite material.So
And, the theoretical specific capacity of graphite is only 372mAh/g, in order to improve energy density and the merit of the negative pole of lithium ion battery further
Rate density, develops novel negative material most important.Owing to the theoretical capacity of silicon is up to 4200mAh/g, simultaneously at nature
Middle rich reserves, therefore has the solution being applied in lithium ion battery negative by silicon materials.General resolving ideas
It is first silicon materials and material with carbon element to be mixed with and obtain Si-C composite material, then Si-C composite material (is led with acetylene black
Electricity agent), Kynoar (binding agent) mixing be made into slurry, even spread to copper foil current collector obtains negative plate.Grind at present
The thinking sent out focuses mostly in Si-C composite material preparation process, obtains the Si-C composite material of some special microstructures, as
Publication No. CN103311523A has the Si-C composite material of nanometer micropore gap, silicon material in Publication No. CN103050672A
Silicon-graphene oxide film that material and material with carbon element prepare after mixing.(conduct electricity with acetylene black again after preparing Si-C composite material
Agent), Kynoar (binding agent) mixing be made into slurry, be applied on Copper Foil make negative plate.This silicon application making is born
The process of pole piece, technical process is loaded down with trivial details, is not suitable for applying in actual industrial production.
[summary of the invention]
The technical problem to be solved is: make up above-mentioned the deficiencies in the prior art, proposes a kind of lithium ion battery
Negative plate and preparation method thereof, lithium ion battery, preparation method simple process, cost is relatively low, and the capacity of the negative plate prepared
Better performances, can meet application demand.
The technical problem of the present invention is solved by following technical scheme:
The preparation method of a kind of anode plate for lithium ionic cell, comprises the following steps: 1) compound concentration is 1～20mg/mL
Graphene oxide solution；2) preparation of nano silicon grain and the mixed solution of polymer；Silicon nanoparticle and polymer are dissolved in alcohol
Aqueous solution prepares described mixed solution, and in described mixed solution, the concentration of described polymer is 1～50mg/mL, described
Silicon nanoparticle is 0.05～1 with the mass ratio of described polymer, and the diameter of described silicon nanoparticle is 30～150nm；3) adopt
By the mode of electrostatic spraying, by fixing for collector on the reception device, step 1 described in electrostatic spraying successively) the oxidation stone for preparing
Ink alkene solution, described step 2) prepare mixed solution, respectively obtain one layer of graphene oxide film and one layer of silicon-polymer thin
Film, is defined as AB layer；And through spraying, the mass ratio of described graphene oxide film and described silicon-thin polymer film be 1:6～
1:9；4) repeat to spray described graphene oxide solution and described mixed solution, form multiple AB layer knot the most on a current collector
Structure；5) collector that will be covered with multiple AB Rotating fields carries out carbonization process, prepares negative plate
The anode plate for lithium ionic cell that a kind of basis preparation method as above prepares.
A kind of lithium ion battery, the negative plate of described lithium ion battery is negative plate as above.
The present invention is compared with the prior art and provides the benefit that:
Anode plate for lithium ionic cell of the present invention and preparation method thereof, the mode using electrostatic spraying is molten by graphene oxide
Liquid direct spraying, on collector, forms graphene oxide film layer, A layer；Then electrostatic spraying is by nano silicon material and polymerization
The mixed solution of thing is sprayed on graphene oxide film layer, forms silicon-polymer film layer, and B layer, through being repeated several times spray
It is coated with, after forming multiple AB Rotating fields on a current collector, collector carbonization together with the multiple AB Rotating fields covered on it is processed,
Directly prepare negative plate.Whole preparation process need not slurrying coating process in tradition preparation process, simple process, and can save
Going the use of conductive agent and binding agent, cost is relatively low.In the negative plate prepared, porous amorphous carbon (polymer carbonization formation) is
Silicon reserves cushion space in the volumetric expansion of process of intercalation, it is ensured that the electron transport ability that material is overall, it is ensured that the appearance of negative plate
Amount performance.And A Rotating fields and B Rotating fields stacked in multi-layers, the volumetric expansion stress that can make silicon is dispersed in layers, it is ensured that negative
The physical arrangement of pole piece is stable.Record according to experiment, the reversible specific capacity first of negative plate prepared 960～1680mAh/g,
After circulation 100 circle, charge specific capacity (de-lithium) is 580～1008mAh/g, and capability retention is 57.6%～74.5%, and performance is relatively
Good, commercial Application requirement can be met.
[accompanying drawing explanation]
Fig. 1 is the preparation method flow chart of the anode plate for lithium ionic cell of the specific embodiment of the invention；
Fig. 2 is the microstructure schematic diagram of the active substance on the negative plate of the specific embodiment of the invention；
Fig. 3 is the SEM photograph of the negative plate prepared in experimental example 3 in the specific embodiment of the invention.
[detailed description of the invention]
Below in conjunction with detailed description of the invention and compare accompanying drawing the present invention is described in further details.
In order to be applied in battery cathode sheet by silicon materials, general thinking has silicon materials nanometer chemical conversion zero dimension, one-dimensional
And two-dimensional material, i.e. nano silicon particles, nano wire, nanotube and nano thin-film.Then silicon materials and material with carbon element are passed through various
Technology controlling and process prepares the silico-carbo composite that structure is special, then the technique that Si-C composite material is coated with by slurrying is coated with
Cloth prepares negative plate on collector.And the present invention be no longer first prepare Si-C composite material after prepare negative plate again, but
Prepare graphene oxide solution, silicon materials solution respectively, formed multilayer laminated arrangement by electrostatic coating the most on a current collector
Graphene film, silicon-thin polymer film, through carbonization process after directly obtain negative plate.Whole preparation process changes often
Rule thinking, and simple process, cost is relatively low, and the volumetric properties of the negative plate prepared is preferable, can meet application demand.
As it is shown in figure 1, be the flow chart of the preparation method of the anode plate for lithium ionic cell of this detailed description of the invention, prepared
Journey comprises the following steps:
S1) compound concentration is the graphene oxide solution of 1～20mg/mL.
Specifically, improvement Hummer's method can be used to prepare graphite oxide, the most accurately weigh the oxidation stone of certain mass
Ink, is dissolved in the deionized water of certain mass, and ultrasonic disperse processes, and the graphene oxide obtaining certain mass mark is equal
Phase aqueous solution, then it is mixed with dehydrated alcohol 1:1 by volume, final prepared concentration is the graphene oxide of 1～20mg/mL
Homogeneous phase solution, be designated as solution M.
S2) preparation of nano silicon grain and the mixed solution of polymer；Silicon nanoparticle and polymer are dissolved in alcohol-water solution
In prepare described mixed solution, and the concentration of described polymer is 1～50mg/mL, described silicon nanoparticle and described polymer
Mass ratio be 0.05～1, the diameter of described silicon nanoparticle is 30～150nm.
Specifically, weighing a certain amount of silicon nanoparticle and polymer, polymer can be sucrose, soluble starch, Fructus Citri Limoniae
Acid, polyvinyl alcohol, polyvinylpyrrolidone, polyaniline, polypyrrole etc. carbonization can become the one in arbitrary polymer of material with carbon element
Or two or more mixing.Silicon nanoparticle and polymer are dissolved in alcohol-water solution, are sufficiently stirred for, ultrasonic disperse,
To silicon nanoparticle and the mixed solution of polymer, it is designated as solution N.
Preferably, when preparing mixed solution, alcohol-water solution adds conductive material, such as acetylene black, and conductive material
It is 0.2～5 with the mass ratio of silicon nanoparticle.When without conductive material, form porous after polymer carbonization amorphous
Carbon base body, energy auxiliary silicon materials conductive, it is ensured that the electric conductivity of active substance in negative plate.After adding conductive material, then can be big
Width promotes the electric conductivity of silicon materials, and then promotes the electric property of the negative plate prepared.
During it is further preferred that prepare mixed solution, alcohol-water solution adds CNT or carbon nano-fiber, receives
The mass ratio of rice carbon pipe or carbon nano-fiber and described silicon nanoparticle is 0.2～5.The CNT added or nanometer
Carbon fiber can play skeletal support effect, stablizes silicon-porous charcoal Rotating fields that follow-up carbonization is formed, promotes the mechanical property of this layer
Energy.CNT or the interpolation of carbon nano-fiber simultaneously, on the one hand contributes to being formed good conductive network, on the other hand can
To promote the mechanical property of active material, and then promote the chemical property of the negative plate prepared.
It should be noted that, the conductive material of interpolation, and CNT or the quality control of carbon nano-fiber, be through
Test of many times determines and obtains, and when controlling within the above range, coordinates the concentration of aforementioned M solution, and in N solution, each component contains
Amount, Comprehensive Control just can ensure that final silicon materials mass fraction in active material layer is at a suitable scope, silicon materials
High theoretical capacity could preferably be brought into play, it is ensured that the volumetric properties of negative plate is preferable.
S3) mode of electrostatic spraying is used, by fixing on the reception device for collector (such as conventional Copper Foil), the most quiet
Step S1 described in electrospray) prepared graphene oxide solution, described step S2) prepared mixed solution, respectively obtain one layer
Graphene oxide film, is defined as A layer and one layer of silicon-thin polymer film, is defined as B layer, thus forms AB layer knot on Copper Foil
Structure；And through spraying, A layer film is 1:6-1:9 with the mass ratio of B layer film.
Specifically, the reception device of electrostatic spraying apparatus fixes copper foil current collector, by step S1) the solution M that configures
Loading in syringe, sprayed by solution with certain flow, electrostatic spray under the high voltage electric field of 10～30kV, spinning head is to receiving
The distance of device is 5～15cm, and ambient temperature is 25 DEG C, and air humidity is 40%, certain time length of spraying, it is ensured that ejection solution
Form the quality that thin film can reach to need.The droplet that spraying is formed obtains after desolvation on the receptor be coated with Copper Foil
One layer of graphene oxide film, is A layer film.Then by step S2) the solution N that configures loads in syringe, with a constant current
Measuring and sprayed by solution, electrostatic spray under the high voltage electric field of 10～30kV, the distance of spinning head to receptor is 5～15cm, week
Enclosing ambient temperature is 25 DEG C, and air humidity is 40%, certain time length of spraying, it is ensured that ejection solution forms thin film can reach needs
Quality.The droplet that spraying is formed obtains one layer of silicon-thin polymer film, on A layer film i.e. on A layer film after desolvation
Define B layer film.
It should be noted that, in above-mentioned M solution and N solution, by parameter determination within the above range, the control of quantity for spray during spraying
System, not the most for it, but comprehensively determines through many experiments and obtains, the concentration (1～20mg/mL) of above-mentioned graphene oxide,
The mass ratio (0.05～1) of the concentration (1～50mg/mL) of polymer, silicon nanoparticle and polymer, A layer film and B during spraying
Mass ratio (1:6～1:9) several parameter joint effect of layer film so that in the final negative plate prepared, silicon materials are at active matter
Mass fraction in matter layer is a suitable scope, thus the high theoretical capacity of silicon materials can preferably be brought into play, really
The volumetric properties protecting negative plate is preferable.
S4) repeat to spray described graphene oxide solution and described mixed solution, form multiple AB the most on a current collector
Rotating fields.In this step, repeat spraying and form multiple structure, thus silicon volumetric expansion stress under height embedding lithium state can be made
Dispersed in layers, it is ensured that the unitary physical structure of negative plate is stable.It should be noted that, for comprising of prepared certain mass
The Graphene of certain mass or silicon-porous carbon material, be preferably provided with single layer structure relatively thin, and the more mode of the number of plies prepares certain
Quality.This mode, and the number of plies less mode thicker relative to single layer structure, the swelling stress dispersion of silicon materials in negative plate
In relatively multiple structure, disperseing more to open, the stability of structure is the best.
Preferably, in step S4) after, entering step S5) before carbonization heat treatment, also include step S4 ') (in figure
Do not illustrate), use the mode of electrostatic spraying, in described step S4) step described in electrostatic spraying on multiple AB Rotating fields of obtaining
1) graphene oxide solution prepared, forms one layer of graphene oxide film.By at B layer film (silicon-thin polymer film) table
Face covers one layer of graphene oxide film of formation, so, when negative plate is used in battery, the graphite oxide of negative plate most surface again
The silicon materials of lower section can be protected by alkene thin film, and the silicon materials below protection are not affected by electrolyte, it is ensured that negative plate
Service life is longer.
S5) collector that will be covered with multiple AB Rotating fields carries out carbonization process, prepares negative plate.
Specifically, when carbonization processes, carry out in high temperature carbonization furnace, in an inert atmosphere, with the intensification of 1～20 DEG C/min
Speed, from room temperature to 500～1000 DEG C, constant temperature 1～3h, after being then cooled to room temperature, is taken out and is obtained described negative plate.One
As collector, such as Copper Foil, its fusing point is higher, is therefore entirely capable of tolerating above-mentioned carbonization high-temperature process, finally prepares negative plate.As
Shown in Fig. 2, for the microstructure schematic diagram of the active material layer on negative plate.Active substance includes the A Rotating fields of stacked arrangement
(rGO that graphene oxide film carbonization is formed) and B Rotating fields (silicon-porous carbon that silicon-thin polymer film carbonization is formed), wherein
B Rotating fields includes the porous carbon materials B02 that polymer carbonization is formed, porous carbon materials parcel silicon materials B01.
Also providing for a kind of lithium ion battery in this detailed description of the invention, its negative plate is preparation method system as described above
The negative plate obtained.
In the preparation method of the negative plate of this detailed description of the invention, whole preparation process is no longer first to prepare silicon-carbon to be combined
Material, the most again by Si-C composite material and conductive agent, is coated with after binding agent slurrying, but after directly preparing solution, electrostatic
After mist, carbonization processes and obtains negative plate, and whole process simplicity is controlled, and without using conductive agent and binding agent, cost is relatively
Low.The negative plate prepared, volumetric properties is preferable, and reversible specific capacity is 960～1680mAh/g first, charge ratio after circulation 100 circle
Capacity (de-lithium) is 580～1008mAh/g, and capability retention, 59.8%～74.5%, can meet commercial Application requirement.
Following by arranging concrete experimental example, the volumetric properties of the negative plate of checking preparation.
Experimental example 1:
The first step: the preparation of graphene oxide homogeneous solution.Improvement Hummer ' s method is used to prepare graphite oxide.Accurately claim
Taking 160mg graphene oxide, be dissolved in the deionized water of 80mL, ultrasonic, the graphene oxide obtaining 2mg/mL is homogeneous
Solution, then it is mixed with dehydrated alcohol 1:1 by volume, obtain the homogeneous phase solution of the graphene oxide of 1mg/mL, be designated as molten
Liquid M.
Second step: the preparation of the mixed solution of silicon nanoparticle and polymer.Precise 40mg silicon nanoparticle (this reality
Test example is selected diameter 30～100nm silicon nanoparticle), the PVP of 200mg is dissolved in the alcohol-water solution of 20mL, fully
Stirring 4h, ultrasonic 1h, obtain the mixed solution of silicon nanoparticle and polymer, be designated as solution N1.Namely in N1 solution, polymer
Concentration be 10mg/mL, the mass ratio of silicon nanoparticle and polymer is 0.2.
3rd step: electrostatic spray solution M.The solution M first step prepared loads in syringe, at the high voltage electric field of 25kV
Lower electrostatic spray, the distance of spinning head to receptor (being fixed with copper foil current collector on receptor) is 5cm, ambient temperature
Being 25 DEG C, air humidity is 40%, and the droplet that spraying is formed middle desolvation on the receptor be coated with Copper Foil obtains thin
Film A.
4th step: electrostatic spray solution N1.The solution N1 prepared by second step loads in syringe, at the high-tension electricity of 25kV
Electrostatic spray after the match, the distance of spinning head to receptor is 5cm, and ambient temperature is 25 DEG C, and air humidity is 40%, former
Thin film B1 is formed on first thin film A.
Wherein in the 3rd step and the 4th step, the flow of spraying and spray time control so that final thin film A and thin film B1's
Mass ratio is 1:6.
5th step: repeat the 3rd step and the 4th step, until forming 10 AB1 laminated construction.
6th step: again through electrostatic spray thin film A on the multi-layer film structure that the 5th step obtains, during electrostatic spray
Control parameter identical with the 3rd step.
7th step: the Copper Foil being coated with multi-layer film structure that the 6th step obtains is carried out heat treatment.To overlay on Copper Foil
The thin film with 10 AB1 laminated construction carry out carbonization treatment.Under high-purity argon gas (purity > 99.999%) protection, with 5
DEG C/programming rate of min is progressively warming up to 600 DEG C from room temperature, and constant temperature 2h, take out sample after being cooled to room temperature, directly obtain
The silicium cathode electrode material of stacked in multi-layers.In this experimental example, on final collector, active substance load capacity is about 0.3mg/cm2。
8th step: electrochemical property test.The membrane electrode that 7th step obtains directly is washed into the electrode of a diameter of 15mm
Sheet, using metal lithium sheet as to electrode, microporous polypropylene membrane (Celgard2400) makees barrier film, and electrolyte is 1mol/LLiPF6Molten
Liquid, solvent is ethylene carbonate (EC)+diethyl carbonate (DEC)+Ethyl methyl carbonate (EMC)+vinylene carbonate (VC) solution,
The volume ratio of EC:DEC:EMC be 1:1:1, VC mass fraction in the electrolytic solution be 2%.Glove box at full high-purity argon gas
In be assembled into 2032 type button cells.Utilize Land battery test system that above-mentioned half-cell at room temperature carries out constant current charge and discharge
Electric performance test, electric current density is 200mA/g, and charging/discharging voltage scope is 0.01～1.0V.
The maximum reversible specific capacity of the negative plate obtained by above-mentioned steps is 1505mAh/g, the charging after circulation 100 circle
Specific capacity (de-lithium) is 900mAh/g, and capability retention is 59.8%.
Experimental example 2: this experimental example, relative to experimental example 1, the difference is that only: in the 3rd step and the 4th step, spraying
Flow and spray time control so that the mass ratio of final thin film A and thin film B1 is 1:7.5.Finally, the negative plate prepared is
Big reversible specific capacity is 1580mAh/g, and the charge specific capacity (de-lithium) after circulation 100 circle is 910mAh/g, capability retention
It is 57.6%.
By experimental example 1 and the comparison of experimental example 2, when the mass ratio of thin film A Yu thin film B1 has adjusted, but
The volumetric properties of the negative plate prepared eventually is similar.It is varied from although possible cause is thin film coated mass ratio, but due to
After polymer P VP carbonization, surplus is less, silicon materials mass fraction in active material layer almost quite (55-60% it
Between), thus cause the performance performance of silicon materials capacity almost identical.
Experimental example 3: this experimental example, relative to experimental example 2, the difference is that only: when second step prepares mixed solution,
Add acetylene black material and nano carbon tube material.
The first step: identical with the first step in experimental example 1, obtains the homogeneous phase solution of the graphene oxide of 1mg/mL, is designated as
Solution M.
Second step: the preparation of the mixed solution of silicon nanoparticle and polymer.Precise 40mg silicon nanoparticle (diameter
Be about 30-100nm), PVP, 20mg multi-walled carbon nano-tubes of 200mg and 40mg acetylene black be dissolved in the alcohol-water solution of 20mL,
It is sufficiently stirred for 4h, ultrasonic 1h, obtains the polymer homogeneous phase solution of silicon nanoparticle, be designated as solution N2.Namely in N2 solution, polymerization
The concentration of thing is 10mg/mL, and silicon nanoparticle is 0.2 with the mass ratio of polymer, conductive material and the quality of silicon nanoparticle
Ratio is 1, and CNT is 0.5 with the mass ratio of silicon nanoparticle.
3rd step: electrostatic spray solution M, spraying process is identical with the 3rd step in experimental example 1, obtains thin film A.
4th step: electrostatic spray solution N2, spraying process is identical with the 4th step in experimental example 1, is formed thin on thin film A
Film B2.
In 3rd step and the 4th step, flow and spray time by spraying control so that final thin film A and thin film B2's
Mass ratio is 1:7.5.
5th step: repeat the 3rd step and the 4th step, until forming 10 AB2 laminated construction.
6th step: again through electrostatic spray thin film A on the multi-layer film structure that the 5th step obtains, during electrostatic spray
Control parameter identical with the 3rd step.
7th step: the Copper Foil being coated with multi-layer film structure that the 6th step obtains is carried out heat treatment.Heat treatment condition with
The 7th step in experimental example 1 is identical.
8th step: electrochemical property test.Test condition is identical with the 8th step in experimental example 1.
The maximum reversible specific capacity of the negative plate obtained by above-mentioned steps is 1020mAh/g, the charging after circulation 100 circle
Specific capacity (de-lithium) is 760mAh/g, and capability retention is 74.5%.The SEM photograph of this negative plate is as it is shown on figure 3, wherein Fig. 3 a
For the photo of negative plate upper surface, Fig. 3 b is the photo of negative plate longitudinal cross-section.Can be seen that from Fig. 3 b there is obvious stacking knot
Structure.
By experimental example 3 and the comparison of experimental example 2, increase acetylene black material when second step prepares mixed solution preparing
Material and nano carbon tube material, can promote the volumetric properties of prepared negative plate.Although increase acetylene black, after nano carbon tube material,
Silicon materials mass fraction in active material layer in the final negative plate prepared is caused to reduce (about 30%), maximum reversible
Specific capacity decreases.But the interpolation of above-mentioned material makes on negative plate collector in active material, CNT, acetylene black are
Silicon materials construct stable conductive network, so that cyclical stability promotes.And the interpolation of CNT makes activity material
The structural stability of material is improved, and finally improves the circulation volume of negative plate in terms of conductive network and structural stability two
Performance.
Experimental example 4: this experimental example, relative to experimental example 3, the difference is that only: in second step in the mixed solution of configuration
In the content of silicon nanoparticle, and the 3rd step and the 4th step, the flow of spraying and spray time control so that final thin film A
Change with the mass ratio of thin film B1.
The first step: identical with the first step in experimental example 3, obtains the homogeneous phase solution of the graphene oxide of 1mg/mL, is designated as
Solution M.
Second step: the preparation of the mixed solution of silicon nanoparticle and polymer.Precise 100mg silicon nanoparticle is (straight
Footpath is about 30-100nm), PVP, 20mg multi-walled carbon nano-tubes of 200mg and 40mg acetylene black be dissolved in the alcohol-water solution of 20mL
In, it is sufficiently stirred for 4h, ultrasonic 1h, obtains the polymer homogeneous phase solution of silicon nanoparticle, be designated as solution N3.Namely in N3 solution,
The concentration of polymer is 10mg/mL, and silicon nanoparticle is 0.5 with the mass ratio of polymer, conductive material and silicon nanoparticle
Mass ratio is 0.4, and CNT is 0.2 with the mass ratio of silicon nanoparticle.
3rd step: electrostatic spray solution M, spraying process is identical with the 3rd step in experimental example 1, obtains thin film A.
4th step: electrostatic spray solution N3, spraying process is identical with the 4th step in experimental example 1, is formed thin on thin film A
Film B3.
In 3rd step and the 4th step, flow and spray time by spraying control so that final thin film A and thin film B2's
Mass ratio is 1:9.
5th step: repeat the 3rd step and the 4th step, until forming 10 AB3 laminated construction.
6th step is to the 8th step: identical to the 8th step with the 6th step in experimental example 3.
The maximum reversible specific capacity of the negative plate obtained by above-mentioned steps is 1680mAh/g, the charging after circulation 100 circle
Specific capacity (de-lithium) is 1008mAh/g, and capability retention is 60%.
By experimental example 4 and the comparison of experimental example 3, prepare mixed solution heighten silicon nanoparticle preparing second step
Content, and improve the relative amount (namely improving silicon materials relative to content of Graphene) of B thin film when electrostatic spray,
The maximum reversible specific capacity performance of prepared negative plate can be promoted, but after circulation, capacity retention can decline accordingly.Can
Seeing, the content increasing silicon materials not necessarily results in the lifting of capability retention.
Experimental example 5: this experimental example, relative to experimental example 3, the difference is that only: in the 3rd step and the 4th step, during spraying
The number of plies change of the change of unit are coating quality and repetition lamination.
The first step: identical with the first step in experimental example 3, obtains the homogeneous phase solution of the graphene oxide of 1mg/mL, is designated as
Solution M.
Second step: identical with the second step in experimental example 3, obtains the polymer homogeneous phase solution of silicon nanoparticle, is designated as molten
Liquid N2.
3rd step: electrostatic spray solution M, spraying process is identical with the 3rd step in experimental example 3, simply unit plane during spraying
Long-pending coating quality is in experimental example 33 times of the 3rd step, thus obtains thin film A.
4th step: electrostatic spray solution N2, spraying process is identical with the 4th step in experimental example 3, simply unit during spraying
The coating quality of area is in experimental example 33 times of the 4th step.
In 3rd step and the 4th step, flow and spray time by spraying control, still such that final thin film A and thin film
The mass ratio of B2 is 1:7.5.
5th step: repeat the 3rd step and the 4th step, until forming 3 AB3 laminated construction.
6th step: the thin film obtained in the 5th step is sprayed thin film A through the 3rd step again, state modulator and the 3rd step phase
With.
7th step is to the 8th step: identical to the 8th step with the 7th step in experimental example 3.
The maximum reversible specific capacity of the negative plate obtained by above-mentioned steps is 1100mAh/g, the charging after circulation 100 circle
Specific capacity (de-lithium) is 660mAh/g, and capability retention is 60%.
By experimental example 5 and the comparison of experimental example 3, prepare the quality that is roughly the same, the active matter of same composition content
Matter, in experimental example 3, stacking divides 10 layers, and every layer of coating quality is less, the scheme of thinner thickness, divides 3 layers than stacking in experimental example 5,
The scheme that every layer thickness is thicker, the conservation rate better performances of capacity, the former is 74.5%, and the latter is only 60%.Show in preparation
Time, the number of plies is more, and it is less that every layer of relatively thin scheme is better than the number of plies, every layer of thicker scheme.
Experimental example 6: this experimental example, relative to experimental example 3, the difference is that only: in the 5th step, repeats the number of plies of lamination
Change, increases to 50 AB2 laminated construction.Finally, the maximum reversible specific capacity of the negative plate prepared is 965mAh/g, circulation
Charge specific capacity (de-lithium) after 100 circles is 580mAh/g, and capability retention is 60.1%.
By experimental example 6 and the comparison of experimental example 3, the lamination number of plies is set to 10 or the scheme of 50
OK.But increasing the lamination number of plies, increase the content of active substance, unit mass specific capacity performance there is no substantially increase, also has on the contrary
Declined.Reason is: if mass percent one timing that silicon is in active material layer, when coating thickness strengthens, away from afflux
The capacity of the active substance of body plays degradation, so the volumetric properties of unit mass ratio there is no substantially increase.
Reference example: take 80mg silicon nanoparticle, by silicon nanoparticle (a diameter of 30～100nm) and graphene oxide, receives
Rice carbon pipe, acetylene black and PVP are 2:2:1:2:10 mix homogeneously according to mass ratio, namely graphene oxide quality: (nano-silicon
Grain+CNT+acetylene black+PVP) quality is 1:7.5 (identical with experimental example 3), the homogeneous mixture carbonization that will be mixed to get
Process and prepare Si-C composite material.Si-C composite material and acetylene black, Kynoar are made slurry for 8:1:1 in mass ratio
Material.Slurry is uniformly coated in copper foil current collector and prepares negative plate.Test the chemical property of this negative plate, test condition with
The 8th step in experimental example 3 is identical.The maximum reversible specific capacity recording negative plate is 980mAh/g, filling after circulation 100 circle
Electricity specific capacity (de-lithium) is 368mAh/g, and capability retention is 37.56%.
Experimental example 1～6 is compared with reference example, it is known that it is right that the volumetric properties of the negative plate that experimental example 1～6 prepares is superior to
The volumetric properties of the negative plate conventionally prepared in ratio.Visible, although material relative composition controls the same, passes through
Electrostatic Spraying technique, and the complex prepared has a structure of stacked in multi-layers, thus the electricity of beneficially holding electrode
Learning and structural stability, the volumetric properties of the negative plate made is better than the simple negative plate mixing carbonization treatment, according to reality
Testing negative plate volumetric properties prepared by the process of example 1～6 all preferable, conservation rate is 57.6%～74.5%.
Above content is to combine concrete preferred implementation further description made for the present invention, it is impossible to assert
Being embodied as of the present invention is confined to these explanations.For general technical staff of the technical field of the invention,
Without departing from making some replacements or obvious modification on the premise of present inventive concept, and performance or purposes are identical, all should be considered as
Belong to protection scope of the present invention.
Claims (9)
1. the preparation method of an anode plate for lithium ionic cell, it is characterised in that: comprise the following steps: 1) compound concentration be 1～
The graphene oxide solution of 20mg/mL；2) preparation of nano silicon grain and the mixed solution of polymer；Described polymer is can carbonization
Become the polymer of material with carbon element；Silicon nanoparticle and polymer are dissolved in alcohol-water solution and prepare described mixed solution, and described
In mixed solution, the concentration of described polymer is 1～50mg/mL, and described silicon nanoparticle with the mass ratio of described polymer is
0.05～1, the diameter of described silicon nanoparticle is 30～150nm；3) use the mode of electrostatic spraying, collector is fixed on and connects
On receiving apparatus, step 1 described in electrostatic spraying successively) graphene oxide solution for preparing, described step 2) mixed solution for preparing,
Respectively obtain one layer of graphene oxide film and one layer of silicon-thin polymer film, be defined as AB layer；And through spraying, described oxidation
Graphene film is 1:6～1:9 with the mass ratio of described silicon-thin polymer film；4) repeat to spray described graphene oxide solution
With described mixed solution, form multiple AB Rotating fields the most on a current collector；5) will be covered with the collector of multiple AB Rotating fields
Carry out carbonization process, prepare negative plate.
The preparation method of anode plate for lithium ionic cell the most according to claim 1, it is characterised in that: described step 2) in,
It is additionally included in described alcohol-water solution addition conductive material and prepares described mixed solution, described conductive material and described nano-silicon
The mass ratio of grain is 0.2～5.
The preparation method of anode plate for lithium ionic cell the most according to claim 1 and 2, it is characterised in that: described step 2)
In, it is additionally included in described alcohol-water solution addition CNT or carbon nano-fiber prepares described mixed solution, described nanometer
The mass ratio of carbon pipe or described carbon nano-fiber and described silicon nanoparticle is 0.2～5.
The preparation method of anode plate for lithium ionic cell the most according to claim 1, it is characterised in that: described step 4) and institute
State step 5) between also include step 4 '): use the mode of electrostatic spraying, in described step 4) on multiple AB Rotating fields of obtaining
Step 1 described in electrostatic spraying) prepare graphene oxide solution, form one layer of graphene oxide film.
The preparation method of anode plate for lithium ionic cell the most according to claim 1, it is characterised in that: described step 3) in quiet
During electrospray solution, voltage of electric field is 10～30kV, and receiving range is 5～15cm.
The preparation method of anode plate for lithium ionic cell the most according to claim 1, it is characterised in that: described step 5) in charcoal
When change processes, carry out in high temperature carbonization furnace, in an inert atmosphere, with the programming rate of 1～20 DEG C/min from room temperature to
500～1000 DEG C, constant temperature 1～3h, after being then cooled to room temperature, takes out and obtains described negative plate.
The preparation method of anode plate for lithium ionic cell the most according to claim 1, it is characterised in that: described step 2) in,
Described polymer is in sucrose, soluble starch, citric acid, polyvinyl alcohol, polyvinylpyrrolidone, polyaniline, polypyrrole
One or more kinds of mixture.
8. the anode plate for lithium ionic cell that a preparation method according to claim 1 prepares.
9. a lithium ion battery, it is characterised in that: the negative plate of described lithium ion battery is negative pole as claimed in claim 8
Sheet.
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Families Citing this family (23)
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| CN108565404A (en) * | 2017-12-23 | 2018-09-21 | 林荣铨 | It is a kind of to prepare application of the graphene/silicon carbon composite in lithium ion battery by carbon source of micro crystal graphite |
| CN108063236A (en) * | 2017-12-23 | 2018-05-22 | 林荣铨 | A kind of method that graphene/silicon carbon composite is prepared using crystalline flake graphite as carbon source |
| CN108063235A (en) * | 2017-12-23 | 2018-05-22 | 林荣铨 | A kind of method that graphene/silicon carbon composite prepares lithium ion battery |
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| EP3654413A1 (en) * | 2018-11-14 | 2020-05-20 | Université de Liège | Silicon-carbon composite anode material |
| CN111085416A (en) * | 2019-12-02 | 2020-05-01 | 深圳石墨烯创新中心有限公司 | Graphene composite metal foil and preparation method thereof |
| CN112927952A (en) * | 2019-12-06 | 2021-06-08 | 中国科学院大连化学物理研究所 | Flexible lithium titanate cathode of lithium ion hybrid capacitor and preparation method thereof |
| CN112436149B (en) * | 2020-11-23 | 2022-03-25 | 北京工业大学 | Si NWs-rGO manufacturing method and Si NWs-rGO lithium ion battery electrode manufacturing method |
| CN113550375B (en) * | 2021-08-03 | 2022-05-17 | 江苏玖润机械工业科技有限公司 | Hydraulic breaking hammer middle cylinder and manufacturing method thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103311502A (en) * | 2013-05-08 | 2013-09-18 | 上海新池能源科技有限公司 | Metal foil/graphene composite electrode plate and preparation method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130189577A1 (en) * | 2011-12-20 | 2013-07-25 | Zheng Wang | Apparatus and method for hot coating electrodes of lithium-ion batteries |
-
2014
- 2014-09-19 CN CN201410484728.6A patent/CN104269515B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103311502A (en) * | 2013-05-08 | 2013-09-18 | 上海新池能源科技有限公司 | Metal foil/graphene composite electrode plate and preparation method thereof |
Non-Patent Citations (2)
| Title |
|---|
| Multilayered Si Nanoparticle/Reduced Graphene Oxide Hybrid as a High-Performance Lithium-Ion Battery Anode;Jingbo Chang等;《Advanced Materials》;20130924;第26卷(第5期);第758-764页 * |
| Silicon–Graphene Composite Anodes for High-Energy Lithium Batteries;Jian-Guo Ren等;《Energy Technology》;20130107;第1卷(第1期);第77-84页 * |
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