CN111244373A - Feedback type lithium ion battery diaphragm material and preparation and application thereof - Google Patents
Feedback type lithium ion battery diaphragm material and preparation and application thereof Download PDFInfo
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- CN111244373A CN111244373A CN202010074408.9A CN202010074408A CN111244373A CN 111244373 A CN111244373 A CN 111244373A CN 202010074408 A CN202010074408 A CN 202010074408A CN 111244373 A CN111244373 A CN 111244373A
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- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- 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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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- 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
- H01M10/058—Construction or manufacture
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- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
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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
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
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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
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
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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
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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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
The invention relates to a reverse feeding type lithium ion battery diaphragm material and preparation and application thereof, wherein the diaphragm material comprises a base material and a composite coating attached to the upper surface and/or the lower surface of the base material, and the composite coating contains a component with the mass ratio of 1: (1-20) the high molecular polymer and silicon powder. Compared with the prior art, the diaphragm material prepared by the invention has the advantages that in the electrolyte environment and the electrochemical environment, the composite coating reacts with lithium to store lithium ions in the form of LixSi (x is an element belonging to (0,4.4)), and the consumption of the lithium ions is supplemented in a shallow charging and shallow discharging manner in the circulating process, so that the coulomb efficiency of a lithium-containing cathode is improved, the circulating life is prolonged, and the energy density of a lithium ion battery is further improved; in addition, the invention further improves the safety and cycle life of lithium-containing negative electrode batteries because LixSi (x ∈ (0,4.4)) which is not fully lithiated can absorb lithium dendrites generated by the negative electrode during cycling through alloying reactions and "back feed" the negative electrode in subsequent cycles.
Description
Technical Field
The invention belongs to the technical field of lithium ion battery diaphragms, and relates to a backswing type lithium ion battery diaphragm material, and preparation and application thereof.
Background
With the rapid development of electronic products, the demand of high-energy, high-power density lithium ion batteries has increased year by year. Lithium metal is considered as the most ideal negative electrode material for new lithium batteries, and has an extremely high theoretical specific capacity (3860mAh g)-1) Low density (0.59g cm)-3) And the most negative electrochemical potential (about-3.04V compared with a standard hydrogen electrode). However, rechargeable batteries based on lithium metal negative electrodes have not been commercialized yet since there are problems of dendrite growth and low Coulombic Efficiency (CE) during repeated charge/discharge of the lithium metal negative electrode.
Because lithium metal is very active, in a battery environment, the surface of lithium inevitably reacts with electrolyte to generate a layer of protective film (SEI) with poor electrochemical performance, and the application and popularization of the lithium metal battery are greatly limited. Currently, common methods for improving the performance of protective films or suppressing spontaneous SEI generation are: electrolyte additive, negative electrode surface coating, mechanical sealing layer, etc. The methods respectively solve the problems of dendritic crystal growth and low coulombic efficiency of the lithium metal negative electrode in the charge-discharge cycle process to a certain extent, but have certain limiting factors respectively. Similarly, lithium-containing alloy negative electrodes, like lithium metal negative electrodes, suffer from problems of lithium dendrite growth and SEI film, which in turn affects coulombic efficiency and long cycle performance.
The construction process of most negative electrode surface coatings has the characteristics of high requirements on the water oxygen content of the coating environment, high requirements on the solvent of a precursor, low production process efficiency, difficulty in control, low universality on the lithium-containing negative electrode material and the like in order to ensure the stability of the lithium-containing negative electrode material in the coating process. In order to improve the universality of the coating material, in recent years, the modification of the negative electrode coating by the modification of the separator coating is generally concerned.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a feedback type lithium ion battery diaphragm material, and preparation and application thereof. In an electrolyte environment and an electrochemical environment, the composite coating reacts with lithium to store lithium ions in a LixSi (x is an element of 0,4.4)), and the consumption of the lithium ions is supplemented in a shallow charging and shallow discharging manner in a circulating process, so that the coulomb efficiency of a lithium-containing cathode is improved, the circulating life is prolonged, and the energy density of a lithium ion battery is further improved; in addition, the invention further improves the safety and cycle life of lithium-containing negative electrode batteries because LixSi (x ∈ (0,4.4)) which is not fully lithiated can absorb lithium dendrites generated by the negative electrode during cycling through alloying reactions and "back feed" the negative electrode in subsequent cycles.
The purpose of the invention can be realized by the following technical scheme:
one of the technical schemes of the invention provides a feedback type lithium ion battery diaphragm material which is characterized by comprising a base material and a composite coating attached to the upper surface and/or the lower surface of the base material, wherein the composite coating contains components with the mass ratio of 1: (1-20) the high molecular polymer and silicon powder.
Further, the base material is a ceramic diaphragm, a PE basal membrane, a PVDF basal membrane or a PP basal membrane and the like.
Further, the high molecular polymer is selected from one or a combination of more of CMC (carboxymethyl cellulose), SBR (styrene butadiene rubber), PVDF, sodium alginate, PAA (polyacrylic acid), PTFE or PVP, and the weight average molecular weight Mw of the high molecular polymer is 10-300 ten thousand.
Further, the thickness of the composite coating is 1-20 μm. (if the thickness is too high, the initial consumption of the lithium source by the silicon coating is too large, which increases the internal resistance of the battery and affects the electrochemical performance; if the thickness is too low, the silicon coating is easily pierced by lithium dendrites and is difficult to protect the lithium-containing negative electrode)
Furthermore, the particle size of the silicon powder is 10 nm-1 μm (the particle size of the silicon powder is too high, the conductivity between particles is too poor, and the reverse feeding effect cannot be realized after lithium source is absorbed), and the particle size of the silicon powder is too low, the lithiation rate of the silicon powder is too high, so that the lithium-containing negative electrode is difficult to be well protected, and the surface smoothness of the lithium-containing negative electrode is realized).
The diaphragm material in the technical scheme is arranged between a lithium ion anode and a lithium-containing cathode, and the composite coating is made to react with lithium in an electrolyte environment and an electrochemical environment to enable the composite coating to be Li-dopedxThe form of Si (x epsilon (0,4.4)) stores lithium ions, supplements the consumption of the lithium ions in a shallow charging and shallow discharging mode in the circulating process, and absorbs lithium dendrites generated in the circulating process through alloying reaction and feeds back the lithium dendrites to the negative electrode in a subsequent circulating process so as to improve the coulombic efficiency, the circulating life and the safety of the lithium-containing negative electrode.
In the diaphragm material, the function of the base material is similar to that of a common diaphragm, the effect of completely isolating the anode and the cathode of the battery is achieved, and the high molecular polymer is mainly used for bonding the silicon powder on the base material, so that the subsequent manufacturing steps are facilitated. The silicon powder firstly generates Li through lithium dendrite in the alloying reaction absorption cycle process in the early stage of the reactionxSi (x ∈ (0,4.4)), and in a full-cell environment, when the degree of polarization of lithium ion extraction from a lithium-containing negative electrode is too large, lithium ions are preferentially extracted from LixSi is produced by dealloying, thereby playing the role of protecting the lithium-containing cathode and realizing the reverse feeding function.
The second technical scheme of the invention provides a preparation method of a membrane separating material of a feedback type lithium ion battery, which is characterized by comprising the following steps:
(1) dissolving a high molecular polymer serving as a solute in a solvent, adding silicon powder, and uniformly mixing to obtain a precursor solution;
(2) and coating the obtained precursor solution on the upper surface and/or the lower surface of the base material, drying to evaporate the solvent, so that a composite coating is formed on the base material, and the target product lithium ion battery diaphragm material is obtained.
Further, in the step (1), the solvent used is selected from one or more of NMP (N-methylpyrrolidone), DMF, ethanol, methanol, acetone or water.
Further, in the step (1), the mass ratio of the high molecular polymer to the solvent is 1: 99-10: 90 (the high molecular polymer acts as a binder in the system, if the content is too high, a side reaction of too much binder is introduced to affect the overall performance of the battery, and if the content is too low, a coating with a proper thickness cannot be prepared).
Further, in the step (2), the coating process conditions are as follows: the environment temperature is 10-60 ℃, the environment humidity is 5-90%, and the coating speed is 1-20 cm/s; (the high-molecular polymer and the diaphragm substrate can generate deformation reaction even the change of microstructure to influence the overall performance if the environmental temperature is too high, the solvent volatilization rate is too low to ensure the solvent volatilization effect if the temperature is too low, the environmental humidity is too high, the solvent is difficult to volatilize to enough little residual quantity, and the high-molecular polymer can be hydrolyzed or deliquesced, the environmental temperature is too low, the solvent can be volatilized completely without the completion of the coating preparation, the feasibility of the production process can not be ensured, the coating speed is too high, the coating can be brushed away along with a coating machine, the coating preparation can not be completed, the coating speed is too low, the solvent can be volatilized completely without the completion of the coating preparation, and the feasibility of the production process can not be ensured.)
After drying, the residual amount of solvent evaporated was not more than 1 wt%.
After the diaphragm material prepared by the simple and universal coating method is assembled in a battery, the diaphragm material can be subjected to in-situ reaction of absorption and release of a lithium source with a lithium-containing negative electrode in a full battery environment to form a continuous interface on the negative electrode, so that the internal resistance of the battery is reduced.
The third technical scheme of the invention provides a lithium ion battery, which comprises a positive plate, a lithium-containing negative plate, the diaphragm material and electrolyte, wherein the positive plate and the lithium-containing negative plate are respectively attached to the two side surfaces of the diaphragm material, and one side surface of the diaphragm material, which contains a composite coating, faces to the lithium-containing negative plate.
Further, the positive plate includes but is not limited to a lithium plate (available from Tianjin from Limited public lithium industry)C.a.600 μm or 100 μm or 50 μm), sulfur-containing positive electrode sheet (active material content of 64 wt%, obtained by freeze drying or hot drying at 60 deg.C), and lithium iron phosphate positive electrode sheet (available from Jiangsu Shuangden group Co., Ltd., area mass density of 200g/cm2) Lithium cobaltate positive plate (purchased from Jiangsu Shuangdeng group Co., Ltd., area mass density of 200 g/cm)2) Ni-Co-Mn ternary lithium positive plate (purchased from Jiangsu Shuangdeng group Co., Ltd., area mass density of 50 g/cm)2Or from polyfluoro-rich New energy science and technology, Inc., and has an areal mass density of 163g/cm2) Or a nickel-cobalt-aluminum ternary lithium positive plate (taking an active material: conductive agent: binder 8:1:1 by hot drying at 100 ℃); the lithium-containing negative electrode sheet includes, but is not limited to, a lithium sheet (available from tianjin lithium industry ltd., c.a.600 μm or 100 μm or 50 μm), a lithium silicon alloy negative electrode sheet (made of silicon: conductive agent: binder: 8:1:1 or 7:2:1 or 6:2:2, and discharged to 0.01V by half-cell electrochemical pre-lithiation to prepare a lithium silicon alloy negative electrode), a lithium carbon composite negative electrode sheet (made of graphite or hard carbon: conductive agent: binder: 90:5:5 or 95:1:4, and discharged to 0.01V by half-cell electrochemical pre-lithiation to prepare a lithium carbon alloy negative electrode), or a lithium tin alloy negative electrode sheet (made of tin: conductive agent: binder: 8:1:1 or 7:2:1 or 6:2:2, and discharged to 0.01V by half-cell electrochemical pre-lithiation to prepare a lithium tin alloy negative electrode); the electrolyte comprises but is not limited to carbonate electrolyte (purchased from a multi-reagent net, and the brands are LB-048, LB-085, LX-025, LB-064 and the like) or ether electrolyte (purchased from a multi-reagent net, and the brands are LS-001, LS-002 and the like).
Compared with the prior art, the lithium-containing cathode has the advantages that the composite coating reacts with lithium in the electrolyte environment and the electrochemical environment, so that the composite coating stores lithium ions in the form of LixSi (x is formed by the element (0,4.4)), the consumption of active lithium ions of the cathode is supplemented in a shallow charging and shallow discharging manner in the circulation process, and meanwhile, lithium dendrites generated in the circulation process are absorbed through alloying reaction and are fed back to the cathode in a back-sequence circulation manner, so that the coulomb efficiency, the circulation life and the safety of the lithium-containing cathode are improved.
Drawings
Fig. 1 is a graph showing cycle performance of lithium batteries manufactured using the lithium battery separators of example 1 and comparative example 1;
fig. 2 is a graph showing cycle performance of lithium batteries manufactured using the lithium battery separators of example 2 and comparative example 2;
FIG. 3 is a time-voltage diagram of symmetric lithium batteries prepared in example 3 and comparative example 3;
FIG. 4 is a time-voltage diagram of symmetric lithium batteries prepared in example 4 and comparative example 4;
fig. 5-8 are graphs of the charge and discharge performance of the button cells obtained in comparative examples 5 to 8, respectively.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
In the following examples, specific sources of the positive electrode sheet and the lithium-containing negative electrode sheet used are as follows:
the positive plate includes, but is not limited to, a lithium plate (available from Tianjin lithium industry Co., Ltd., c.a.600 μm or 100 μm or 50 μm), a sulfur-containing positive plate (having an active material content of 64 wt%, and obtained by freeze-drying or hot-drying at 60 ℃), and a lithium iron phosphate positive plate (available from Jiangsu Shuangden group Co., Ltd., having an areal mass density of 200g/cm2) Lithium cobaltate positive plate (purchased from Jiangsu Shuangdeng group Co., Ltd., area mass density of 200 g/cm)2) Ni-Co-Mn ternary lithium positive plate (purchased from Jiangsu Shuangdeng group Co., Ltd., area mass density of 50 g/cm)2Or from polyfluoro-rich New energy science and technology, Inc., and has an areal mass density of 163g/cm2) Or a nickel-cobalt-aluminum ternary lithium positive plate (taking an active material: conductive agent: binder 8:1:1 by hot drying at 100 ℃);
the lithium-containing negative electrode sheet includes, but is not limited to, a lithium sheet (available from tianjin lithium industries ltd., c.a.600 μm or 100 μm or 50 μm), a lithium silicon alloy negative electrode sheet (made of silicon: conductive agent: binder: 8:1:1 or 7:2:1 or 6:2:2, and discharged to 0.01V by half-cell electrochemical pre-lithiation to prepare a lithium silicon alloy negative electrode), a lithium carbon composite negative electrode sheet (made of graphite or hard carbon: conductive agent: binder: 90:5:5 or 95:1:4, and discharged to 0.01V by half-cell electrochemical pre-lithiation to prepare a lithium carbon alloy negative electrode), or a lithium tin alloy negative electrode sheet (made of tin: conductive agent: binder: 8:1:1 or 7:2:1 or 6:2:2, and discharged to 0.01V by half-cell electrochemical pre-lithiation to prepare a lithium tin alloy negative electrode); the electrolyte comprises but is not limited to carbonate electrolyte (purchased from a multi-reagent net, and the brands are LB-048, LB-085, LX-025, LB-064 and the like) or ether electrolyte (purchased from a multi-reagent net, and the brands are LS-001, LS-002 and the like).
The rest is conventional commercial raw materials or conventional processing techniques in the field if the raw material reagents or processing techniques are not specifically mentioned.
Example 1:
a lithium battery diaphragm for improving the coulomb efficiency, the cycle life and the safety of a lithium-containing cathode comprises the following steps:
the method comprises the following steps: high molecular polymer PVP with the molecular weight of 130 ten thousand is used as a solute, DMF is used as a solvent, the solute and the solvent are mixed according to the mass ratio of 5: 95, the solute is completely dissolved in the oily solvent, then silicon powder with the particle size of 10nm is added, the mass ratio of the PVP to the silicon powder is 1: 20, stirring is carried out for 20min, and precursor solution is prepared for standby.
Step two: selecting a PP basal membrane with the size of 100mm multiplied by 25mm and the thickness of 25 mu m as a base material, and uniformly coating the prepared precursor solution on the upper surface and/or the lower surface of the base material.
Step three: and (3) putting the coated base material into a vacuum oven, and baking for 12 hours at 45 ℃ in vacuum to dry so that the solvent is completely evaporated, and forming a composite coating with the thickness of 20 mu m on the surface of the base material to obtain the lithium battery diaphragm.
Step four: punching the prepared lithium battery diaphragm into a wafer by using a grinding tool, and placing the diaphragm in a nickel-cobalt-manganese ternary lithium positive plate (polyfluoro-multi-new energy, 163 g/cm)2) Placing the composite coating facing the lithium sheet cathode between the cathode and the lithium sheet cathode (C.a.600 μm) in a CR2032 button battery case, adding carbonate (multiple reagent net, LB-048) electrolyte, and making into buttonThe battery is subjected to charge and discharge tests, and the attached figure 1 is a cycle performance diagram of the battery. The reversible cycle capacity and coulombic efficiency stability of example 1 were both improved compared to comparative example 1.
Example 2:
a lithium battery diaphragm for improving the coulomb efficiency, the cycle life and the safety of a lithium-containing cathode comprises the following steps:
the method comprises the following steps: high molecular polymer PAA with molecular weight of 45 ten thousand is used as solute, NMP is used as solvent, the solute and the solvent are mixed according to the mass ratio of 1:99, the solute is completely dissolved in the oily solvent, then silicon powder with the particle size of 30nm is added, the mass ratio of the PAA to the silicon powder is 1:9, stirring is carried out for 10min, and precursor solution is prepared for standby.
Step two: selecting a PE base film with the size of 100mm multiplied by 25mm and the thickness of 21 mu m as a base material, and uniformly coating the prepared precursor solution on the upper surface and/or the lower surface of the base material.
Step three: and (3) putting the coated base material into a vacuum oven, and baking for 12 hours at 50 ℃ in vacuum to dry so that the solvent is completely evaporated, and forming a composite coating with the thickness of 1 mu m on the surface of the base material to obtain the lithium battery diaphragm.
Step four: punching the prepared lithium battery diaphragm into a circular sheet by using a grinding tool, and placing the diaphragm into a lithium iron phosphate positive plate (a doubly-bonded group, 200 g/cm)2) With a lithium carbon negative electrode (taking graphite or hard carbon: conductive agent: binder 90:5:5 or 95:1:4, performing electrochemical pre-lithiation on a half-cell, discharging to 0.01V to obtain a lithium-carbon alloy negative electrode), putting the composite coating facing the lithium-carbon negative electrode into a CR2032 button cell case, adding a carbonate electrolyte (a multi-reagent net, LB-085) to prepare a button cell, and performing charge and discharge tests on the button cell, wherein the attached figure 2 is a cycle performance diagram. The reversible cycle capacity and coulombic efficiency stability of example 2 were both improved compared to comparative example 2.
Example 3:
a lithium battery diaphragm for improving the coulomb efficiency, the cycle life and the safety of a lithium-containing cathode comprises the following steps:
the method comprises the following steps: high molecular polymer PAA with the molecular weight of 50 ten thousand is used as a solute, ethanol is used as a solvent, the solute and the solvent are mixed according to the mass ratio of 10:90, the solute is completely dissolved in the solvent, then silicon powder with the particle size of 20nm is added, the mass ratio of the PAA to the silicon powder is 1:4, stirring is carried out for 10min, and precursor solution is prepared for standby.
Step two: selecting a PP basal membrane with the size of 100mm multiplied by 25mm and the thickness of 25 mu m as a base material, and uniformly coating the prepared precursor solution on the upper surface and/or the lower surface of the base material.
Step three: and putting the coated base material into a vacuum oven, and baking for 12 hours at 50 ℃ in vacuum to dry so that the solvent is completely evaporated, and forming a composite coating with the thickness of 10 mu m on the surface of the base material to obtain the lithium battery diaphragm.
Step four: the prepared lithium battery diaphragm is punched into a wafer by using a grinding tool, the wafer is placed between a lithium anode (middle energy lithium industry, c.a.100 mu m) and a lithium cathode (middle energy lithium industry, c.a.100 mu m), a composite coating faces to the lithium cathode, the wafer and the lithium cathode are placed into a CR2032 button battery case together, a carbonate (multi-reagent net, LB-064) electrolyte is added to prepare a button battery, and a charge and discharge test is carried out on the button battery, wherein the attached figure 3 is a time-voltage diagram. The stable polarization cycle time of example 3 was significantly prolonged and the voltage polarization of example 3 was also significantly reduced compared to comparative example 3.
Example 4:
a lithium battery diaphragm for improving the coulomb efficiency, the cycle life and the safety of a lithium-containing cathode comprises the following steps:
the method comprises the following steps: taking high molecular polymer sodium alginate with molecular weight of 27 ten thousand as a solute and water as a solvent, mixing the solute and the solvent according to the mass ratio of 4: 96 to completely dissolve the solute in the solvent, then adding silicon powder with the particle size of 30nm, stirring for 20min, and preparing a precursor solution for later use, wherein the mass ratio of the sodium alginate to the silicon powder is 2: 8.
Step two: selecting a ceramic base film with the size of 100mm multiplied by 25mm and the thickness of 26 mu m as a base material, and uniformly coating the prepared precursor solution on the upper surface and/or the lower surface of the base material.
Step three: and (3) putting the coated base material into a vacuum oven, and baking for 12 hours at 40 ℃ in vacuum to dry so that the solvent is completely evaporated, and forming a composite coating with the thickness of 3 mu m on the surface of the base material to obtain the lithium battery diaphragm.
Step four: the prepared lithium battery diaphragm is punched into a wafer by using a grinding tool, the wafer is placed between a lithium anode (middle energy lithium industry, c.a.50 mu m) and a lithium cathode (middle energy lithium industry, c.a.50 mu m), a composite coating faces to the lithium-containing cathode, the wafer and the lithium cathode are placed into a CR2032 button battery case together, ether (multi-reagent, LS-001) electrolyte is added to prepare a button battery, the button battery is subjected to charge and discharge tests, and the attached figure 4 is a time-voltage diagram thereof. The stable polarization cycle time of example 4 was significantly prolonged and the voltage polarization of example 4 was also significantly reduced compared to comparative example 4.
Comparative example 1:
punching PP basal membrane with thickness of 25 μm into round piece with grinding tool, and placing into Ni-Co-Mn ternary lithium positive plate (polyfluoro-multi-new energy, 163 g/cm)2) And between the lithium plate negative electrode (middle energy lithium industry, c.a.600 mu m), the composite coating faces the lithium plate negative electrode, the lithium plate negative electrode and the composite coating are placed into a CR2032 button battery case together, carbonate (multi-reagent, LB-048) electrolyte is added to prepare a button battery, a charge-discharge test is carried out on the button battery, and the charge-discharge test is carried out on the button battery, wherein the attached figure 1 is a cycle performance diagram.
Comparative example 2:
a PE base film with the thickness of 21 mu m is punched into a wafer by using a grinding tool, the wafer is placed between a lithium iron phosphate positive plate (a doubly charged group, 200g/cm2) and a lithium carbon negative electrode (graphite or hard carbon: a conductive agent: a binder: 90:5:5 or 95:1:4, the lithium carbon negative electrode is prepared by half-cell electrochemical pre-lithiation and discharging to 0.01V), the wafer and the lithium carbon negative electrode are placed into a CR2032 button battery case together, a carbonate electrolyte (a multi-reagent, LB-085) is added to prepare a button battery, and the button battery is subjected to charging and discharging tests, wherein the attached figure 2 shows a cycle performance chart.
Comparative example 3:
a PP (polypropylene) base film with the thickness of 25 mu m is punched into a wafer by using a grinding tool, the wafer is placed between a lithium anode (middle energy lithium industry, c.a.100 mu m) and a lithium cathode (middle energy lithium industry, c.a.100 mu m), a composite coating faces to the lithium cathode, the wafer and the lithium cathode are placed into a CR2032 button battery case together, a carbonate (multi-reagent, LB-064) electrolyte is added to prepare a button battery, and a charge-discharge test is carried out on the button battery, wherein the attached figure 3 is a time-voltage diagram.
Comparative example 4:
punching a ceramic base film with the thickness of 26 mu m into a wafer by using a grinding tool, placing the wafer between a lithium anode (middle energy lithium industry, c.a.50 mu m) and a lithium cathode (middle energy lithium industry, c.a.50 mu m), placing a composite coating facing the lithium cathode into a CR2032 button battery case, adding ether (multi-reagent, LS-001) electrolyte to prepare a button battery, and carrying out charge and discharge tests on the button battery, wherein the attached figure 4 is a time-voltage diagram thereof.
Comparative example 5:
compared to example 2, most of them were the same except that the silicon powder was omitted.
The manufacturing method comprises the following steps:
the method comprises the following steps: high molecular polymer PAA with molecular weight of 45 ten thousand is used as solute, NMP is used as solvent, the solute and the solvent are mixed according to the mass ratio of 1:99, so that the solute is completely dissolved in the oily solvent, and precursor solution is prepared for standby.
Step two: selecting a PE base film with the size of 100mm multiplied by 25mm and the thickness of 21 mu m as a base material, and uniformly coating the prepared precursor solution on the upper surface and/or the lower surface of the base material.
Step three: and (3) putting the coated base material into a vacuum oven, and baking for 12 hours at 50 ℃ in vacuum to dry so that the solvent is completely evaporated, and forming a composite coating with the thickness of 1 mu m on the surface of the base material to obtain the lithium battery diaphragm.
Step four: punching the prepared lithium battery diaphragm into a circular sheet by using a grinding tool, and placing the diaphragm into a lithium iron phosphate positive plate (a doubly-bonded group, 200 g/cm)2) With a lithium carbon negative electrode (graphite or hard carbon: conductive agent: binder 90:5:5 or 95:1:4, performing electrochemical pre-lithiation on a half-cell, discharging to 0.01V to obtain a lithium-carbon alloy negative electrode), putting the composite coating facing the lithium-carbon negative electrode into a CR2032 button cell case, adding carbonate electrolyte (multi-reagent, LB-085) to prepare a button cell, and performing charge and discharge tests on the button cell. Referring to FIG. 5, the corresponding battery cycling testIn the test, the battery capacity decayed dramatically as the charging and discharging processes proceeded.
Comparative example 6:
compared with example 2, most of them are the same except that the high molecular polymer is omitted.
The manufacturing method comprises the following steps:
the method comprises the following steps: uniformly mixing silicon powder and NMP according to the mass ratio of 1:99 to prepare a precursor solution for later use.
Step two: selecting a PE base film with the size of 100mm multiplied by 25mm and the thickness of 21 mu m as a base material, and uniformly coating the prepared precursor solution on the upper surface and/or the lower surface of the base material.
Step three: and (3) putting the coated base material into a vacuum oven, and baking for 12 hours at 50 ℃ in vacuum to dry so that the solvent is completely evaporated, and forming a composite coating with the thickness of 1 mu m on the surface of the base material to obtain the lithium battery diaphragm.
Step four: the prepared lithium battery diaphragm is punched into a circular sheet by using a grinding tool, the diaphragm is placed between a lithium iron phosphate positive plate (a doubly-modified group, 200g/cm2) and a lithium carbon negative electrode (graphite or hard carbon: a conductive agent: a binder: 90:5:5 or 95:1:4, and the lithium carbon negative electrode is prepared by discharging to 0.01V through half-cell electrochemical pre-lithiation), a composite coating faces the lithium carbon negative electrode, the composite coating is placed into a CR2032 button battery case together, a carbonate electrolyte (a multi-reagent, LB-085) is added, a button battery is prepared, and a charge and discharge test is carried out on the button battery, as shown in figure 6, the capacity of the battery continuously attenuates in the corresponding battery cycle performance test.
Comparative example 7:
compared with example 2, most of them are the same except that the mass ratio of PAA to silicon powder is 2: 1.
the manufacturing method comprises the following steps:
the method comprises the following steps: taking high molecular polymer PAA with molecular weight of 45 ten thousand as solute and NMP as solvent, mixing the solute and the solvent according to the mass ratio of 1:99, completely dissolving the solute in the oily solvent, then adding silicon powder with the particle size of 30nm, stirring for 10min, and preparing into precursor solution for later use, wherein the mass ratio of the PAA to the silicon powder is 2: 1.
Step two: selecting a PE base film with the size of 100mm multiplied by 25mm and the thickness of 21 mu m as a base material, and uniformly coating the prepared precursor solution on the upper surface and/or the lower surface of the base material.
Step three: and (3) putting the coated base material into a vacuum oven, and baking for 12 hours at 50 ℃ in vacuum to dry so that the solvent is completely evaporated, and forming a composite coating with the thickness of 1 mu m on the surface of the base material to obtain the lithium battery diaphragm.
Step four: punching the prepared lithium battery diaphragm into a circular sheet by using a grinding tool, and placing the diaphragm into a lithium iron phosphate positive plate (a doubly-bonded group, 200 g/cm)2) With a lithium carbon negative electrode (graphite or hard carbon: conductive agent: binder 90:5:5 or 95:1:4, performing electrochemical pre-lithiation on a half-cell, discharging to 0.01V to obtain a lithium-carbon alloy negative electrode), putting the composite coating facing the lithium-carbon negative electrode into a CR2032 button cell case, adding carbonate electrolyte (multi-reagent, LB-085) to prepare a button cell, and performing charge and discharge tests on the button cell. Referring to fig. 7, the corresponding battery test was stable in the early stages, but the capacity was drastically reduced after 30 cycles.
Comparative example 8:
compared with example 2, most of them are the same except that the mass ratio of PAA to silicon powder is 1: 25.
the manufacturing method comprises the following steps:
the method comprises the following steps: taking high molecular polymer PAA with molecular weight of 45 ten thousand as solute and NMP as solvent, mixing the solute and the solvent according to the mass ratio of 1:99, completely dissolving the solute in the oily solvent, then adding silicon powder with the particle size of 30nm, stirring for 10min, and preparing into precursor solution for later use.
Step two: selecting a PE base film with the size of 100mm multiplied by 25mm and the thickness of 21 mu m as a base material, and uniformly coating the prepared precursor solution on the upper surface and/or the lower surface of the base material.
Step three: and (3) putting the coated base material into a vacuum oven, and baking for 12 hours at 50 ℃ in vacuum to dry so that the solvent is completely evaporated, and forming a composite coating with the thickness of 1 mu m on the surface of the base material to obtain the lithium battery diaphragm.
Step four: punching the prepared lithium battery diaphragm into a wafer by using a grinding tool, placing the diaphragm between a lithium iron phosphate positive plate (a doubly charged group, 200g/cm2) and a lithium carbon negative electrode (graphite or hard carbon: a conductive agent: a binder: 90:5:5 or 95:1:4, performing half-cell electrochemical pre-lithiation, discharging to 0.01V to prepare a lithium carbon alloy negative electrode), placing the composite coating facing the lithium carbon negative electrode into a CR2032 button battery case, adding a carbonate electrolyte (a multi-reagent, LB-085) to prepare a button battery, and performing charge and discharge tests on the button battery. Referring to fig. 8, in the cycle performance test, the capacity of the corresponding battery is attenuated continuously, and the capacity is attenuated severely around 55 cycles.
In addition, in the above embodiments, the base material may be arbitrarily adjusted to a ceramic separator, a PE-based film, a PVDF-based film, a PP-based film, or the like; the high molecular polymer can be arbitrarily adjusted to be one or a combination of more of CMC (carboxymethyl cellulose), SBR (styrene butadiene rubber), PVDF, sodium alginate, PAA (polyacrylic acid), PTFE or PVP, and the weight average molecular weight Mw of the high molecular polymer is 10-300 ten thousand.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.
Claims (10)
1. The feedback type lithium ion battery diaphragm material is characterized by comprising a base material and a composite coating attached to the upper surface and/or the lower surface of the base material, wherein the composite coating comprises the following components in a mass ratio of 1: (1-20) the high molecular polymer and silicon powder.
2. The feedback type lithium ion battery separator material of claim 1, wherein the substrate is a ceramic separator, a PE-based film, a PVDF-based film, or a PP-based film;
the high molecular polymer is selected from one or a combination of more of CMC, SBR, PVDF, sodium alginate, PAA, PTFE or PVP, and the weight average molecular weight of the high molecular polymer is 10-300 ten thousand.
3. The feedback type lithium ion battery separator material of claim 1, wherein the thickness of the composite coating layer is 1-20 μm.
4. The feedback type lithium ion battery separator material of claim 1, wherein the particle size of the silicon powder is 10 nm-1 μm.
5. The method for preparing the membrane separating material of the regurgitation-type lithium ion battery as defined in any one of claims 1 to 4, comprising the steps of:
(1) dissolving a high molecular polymer serving as a solute in a solvent, adding silicon powder, and uniformly mixing to obtain a precursor solution;
(2) and coating the obtained precursor solution on the upper surface and/or the lower surface of the base material, drying to evaporate the solvent, so that a composite coating is formed on the base material, and the target product lithium ion battery diaphragm material is obtained.
6. The method for preparing a membrane separating material of a feedback type lithium ion battery according to claim 5, wherein in the step (1), the solvent is selected from one or more of NMP, DMF, ethanol, methanol, acetone or water.
7. The method for preparing the membrane separation material of the feedback type lithium ion battery according to claim 5, wherein in the step (1), the mass ratio of the high molecular polymer to the solvent is 1: 99-10: 90.
8. The method for preparing the membrane separating material of the feedback type lithium ion battery according to claim 5, wherein in the step (2), the coating process conditions are as follows: the environment temperature is 10-60 ℃, the environment humidity is 5-90%, and the coating speed is 1-20 cm/s;
after drying, the residual amount of solvent evaporated was not more than 1 wt%.
9. A lithium ion battery, which comprises a positive plate, a lithium-containing negative plate, the diaphragm material according to any one of claims 1 to 4, and electrolyte, wherein the positive plate and the lithium-containing negative plate are respectively attached to two side surfaces of the diaphragm material, and one side surface of the diaphragm material, which contains a composite coating, faces to the lithium-containing negative plate.
10. The lithium ion battery of claim 9, wherein the positive electrode sheet is a lithium sheet, a sulfur-containing positive electrode sheet, a lithium iron phosphate positive electrode sheet, a lithium cobaltate positive electrode sheet, a nickel cobalt manganese ternary lithium positive electrode sheet, or a nickel cobalt aluminum ternary lithium positive electrode sheet;
the lithium-containing negative plate is a lithium plate, a silicon-lithium alloy negative plate, a lithium-carbon composite negative plate or a lithium-tin alloy negative plate;
the electrolyte is carbonate electrolyte or ether electrolyte.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112194914A (en) * | 2020-08-28 | 2021-01-08 | 河北金力新能源科技股份有限公司 | Lithium battery diaphragm slurry, lithium battery diaphragm prepared from same and lithium battery |
| WO2021017801A1 (en) * | 2019-07-26 | 2021-02-04 | 宁德时代新能源科技股份有限公司 | Functionalized isolation film, preparation method therefor, lithium metal battery, and device comprising same |
| CN114335900A (en) * | 2021-12-30 | 2022-04-12 | 珠海冠宇电池股份有限公司 | Diaphragm and battery containing same |
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| CN109244332A (en) * | 2018-10-15 | 2019-01-18 | 上海力信能源科技有限责任公司 | Improve the lithium battery diaphragm of siliceous negative electrode material head effect and the lithium battery of production method, preparation |
| CN110247009A (en) * | 2019-07-03 | 2019-09-17 | 珠海冠宇电池有限公司 | A kind of anti-overcharge diaphragm and preparation method thereof and lithium ion battery |
| CN110364662A (en) * | 2018-04-11 | 2019-10-22 | 宁德新能源科技有限公司 | Isolation film and electrochemical appliance |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110364662A (en) * | 2018-04-11 | 2019-10-22 | 宁德新能源科技有限公司 | Isolation film and electrochemical appliance |
| CN109244332A (en) * | 2018-10-15 | 2019-01-18 | 上海力信能源科技有限责任公司 | Improve the lithium battery diaphragm of siliceous negative electrode material head effect and the lithium battery of production method, preparation |
| CN110247009A (en) * | 2019-07-03 | 2019-09-17 | 珠海冠宇电池有限公司 | A kind of anti-overcharge diaphragm and preparation method thereof and lithium ion battery |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2021017801A1 (en) * | 2019-07-26 | 2021-02-04 | 宁德时代新能源科技股份有限公司 | Functionalized isolation film, preparation method therefor, lithium metal battery, and device comprising same |
| CN112194914A (en) * | 2020-08-28 | 2021-01-08 | 河北金力新能源科技股份有限公司 | Lithium battery diaphragm slurry, lithium battery diaphragm prepared from same and lithium battery |
| CN114335900A (en) * | 2021-12-30 | 2022-04-12 | 珠海冠宇电池股份有限公司 | Diaphragm and battery containing same |
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Application publication date: 20200605 |