CN115911366A - Modified positive electrode lithium supplement material, lithium ion battery positive electrode and lithium ion battery - Google Patents
Modified positive electrode lithium supplement material, lithium ion battery positive electrode and lithium ion battery Download PDFInfo
- Publication number
- CN115911366A CN115911366A CN202310111395.1A CN202310111395A CN115911366A CN 115911366 A CN115911366 A CN 115911366A CN 202310111395 A CN202310111395 A CN 202310111395A CN 115911366 A CN115911366 A CN 115911366A
- Authority
- CN
- China
- Prior art keywords
- lithium
- positive electrode
- rich oxide
- ion battery
- oxide particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention discloses a modified anode lithium supplement material, a lithium ion battery anode and a lithium ion battery. Modified according to the inventionThe lithium-supplementing material comprises lithium-rich oxide particles and a coating layer which is coated on the surfaces of the lithium-rich oxide particles and is made of polysiloxane compounds; the lithium-rich oxide particles are Li 5 FeO 4 、Li 6 CoO 4 And Li 2 NiO 2 Any one of (a) to (b); the polysiloxane compound is selected from any one of polydimethylsiloxane, polymethylphenylsiloxane and polyphenylmethylsiloxane; wherein the polysiloxane compound is cross-linked between the lithium-rich oxide particles. According to the invention, polyalkylene oxide is uniformly coated on the surfaces of lithium-rich oxide particles and effective cross-linking is formed among the particles, so that 3D high-efficiency Li is constructed + A transmission network is used for improving the capacity; effectively isolating the lithium-rich oxide from contacting with moisture in the air, reducing surface residual alkali, improving the structural stability of the lithium-rich oxide, obviously prolonging the coating window period during processing and effectively improving the problem of slurry gelation.
Description
Technical Field
The invention relates to the technical field of lithium supplement of a lithium ion battery anode, in particular to a modified anode lithium supplement material, a lithium ion battery anode and a lithium ion battery.
Background
In recent years, portable electronic products, new energy vehicles, smart power grids, distributed energy storage, internet of things and the like are rapidly developed, and higher requirements are put forward on various performances of lithium ion batteries, wherein the improvement on the energy density of the batteries is the most urgent. The lithium ion battery lithium supplement technology is also becoming a hot research direction as an important means for improving the energy density of the battery. Most of the existing high-specific-capacity electrode materials lose a large amount of active lithium due to the formation of an SEI film during first charge and discharge, so that the initial cycle coulombic efficiency (ICE) is low, and the capacity and energy density of a lithium ion battery are reduced. The irreversible capacity loss of the graphite cathode which is most widely used at present is more than 6 percent, and for silicon-based and tin-based alloy cathodes with high specific capacity, the irreversible capacity loss is even more than 10 to 20 percent. The active lithium with the first cycle loss can be compensated by matching with a lithium supplement technology, a short plate with low first effect is improved, the advantage of high capacity of the short plate is fully exerted, and the effect of improving the energy density of the lithium ion battery is achieved.
The lithium-rich oxide system is used as an important positive electrode lithium supplement additive, and has the advantages of good compatibility with a battery system, low production cost, no toxicity and high lithium supplement capacity, and is widely concerned by researchers. However, current research shows that lithium is richOxide material versus environment (H) 2 O and CO 2 ) The lithium-rich oxide is extremely sensitive and has low intrinsic conductivity, so that the industrialization and application difficulty is extremely high, the market popularization is limited, the current domestic and foreign markets are still in the application, development and verification stage of lithium-rich oxide products, the problems of poor production stability, difficulty in processing and the like exist, and large-scale production and application are not available. At the same time, because of the existence of a large amount of free Li on the surface + The residual alkali is high, and when the lithium ion battery is put into a positive electrode, the slurry is usually gelled and cannot be coated, so that the popularization and application of a lithium supplement technology are greatly limited.
Disclosure of Invention
Aiming at the problems of poor stability of a lithium-rich oxide, poor processability, low ionic conductivity, large polarization and the like of the conventional positive electrode lithium supplement material, the invention aims to provide the modified positive electrode lithium supplement material, a lithium ion battery positive electrode and a lithium ion battery.
In a first aspect, the invention provides a modified positive electrode lithium supplement material, which comprises lithium-rich oxide particles and a coating layer which is coated outside the lithium-rich oxide particles and is made of polysiloxane compounds;
the lithium-rich oxide particles are Li 5 FeO 4 、Li 6 CoO 4 And Li 2 NiO 2 Any one of (a) to (b);
the polysiloxane compound is selected from any one of polydimethylsiloxane, polymethylphenylsiloxane and polyphenyl methylsiloxane;
wherein the polysiloxane compound is cross-linked between the lithium-rich oxide particles.
In the modified positive electrode lithium supplement material, the mass ratio of the polysiloxane compound to the lithium-rich oxide particles may be (0.01 to 0.10): 1, specifically (0.02 to 0.10): 1. (0.04-0.10): 1. (0.02 to 0.04): 1. 0.10: 1. 0.04:1 or 0.02:1;
the thickness of the coating layer may be 0.1 to 1.0. Mu.m, specifically 0.1 to 0.6. Mu.m, 0.1 to 0.5. Mu.m, 0.1 to 0.2. Mu.m, 0.2 to 0.6. Mu.m, 0.2 to 0.5. Mu.m, 0.5 to 0.6. Mu.m, 0.5. Mu.m, 0.1. Mu.m, 0.2. Mu.m, or 0.6. Mu.m.
In the modified positive electrode lithium supplement material, the lithium-rich oxide particles may have an average diameter of 0.5 to 10 μm, specifically 1 to 8 μm, 1 to 5 μm, 1 to 3 μm, 1 to 2 μm, 2 to 8 μm, 2 to 5 μm, 2 to 3 μm, 3 to 8 μm, 3 to 5 μm, 5 to 8 μm, 5 μm, 3 μm, 2 μm, 8 μm, or 1 μm.
In the modified positive electrode lithium supplement material, the polydimethylsiloxane (molecular formula is (C) 2 H 6 OSi) n ) The molecular weight of (b) may be 1000 to 5000, specifically 2500;
the polymethylphenylsiloxane has a molecular formula of (C) 7 H 8 OSi) n ) The molecular weight of (A) is 1000-3000, specifically 2700;
the polyphenyl methylsiloxane (molecular formula is (C) 6 H 5 (CH 3 )SiO 2 ) n ) The molecular weight of (A) is 2000-5000, specifically 2500.
In a second aspect, the invention provides a method for preparing the modified cathode lithium supplement material, which comprises the following steps:
s1, placing the lithium-rich oxide particles in an organic solvent for ultrasonic treatment, and drying after the ultrasonic treatment;
and S2, taking the polysiloxane compound as a deposition material, and carrying out chemical vapor deposition on the lithium-rich oxide particles treated in the step S1 under the protection of inert atmosphere to form the coating layer, so as to obtain the modified cathode lithium supplement material.
In the above preparation method, the organic solvent is any one of absolute ethyl alcohol, absolute methyl alcohol, isopropyl alcohol, acetonitrile and acetone;
the power of the ultrasonic treatment can be 80-200W, specifically 80-150W, 80-100W, 100-150W, 100-200W, 150-200W, 80W, 200W, 100W or 150W, and the time can be 15-60 min, specifically 15-50 min, 15-30 min, 30-50 min, 30-60 min, 50-60 min, 15min, 30min or 50min;
the drying temperature can be 60-120 ℃, specifically 80-120 ℃, 80 ℃ or 120 ℃; the time can be 8-24 h, specifically 8-16 h, 16-24 h, 8h, 16h and 24h; the vacuum degree is less than or equal to-0.02 MPa, and can be specifically-0.09 MPa to-0.02 MPa, -0.09MPa to-0.05 MPa, -0.05MPa to-0.02 MPa, -0.05MPa, -0.09MPa or-0.02 MPa.
In the above preparation method, the temperature of the chemical vapor deposition may be 200 to 300 ℃, specifically 200 to 250 ℃, 250 to 300 ℃, 200 ℃ or 250 ℃; the time can be 0.5-5 h, specifically 1-2 h, 2h or 1h.
In the above preparation method, the inert gas may be nitrogen or argon.
In a third aspect, the invention provides an application of the modified positive electrode lithium supplement material in any one of the following 1) to 3):
1) Reducing the content of residual alkali LiOH on the surface;
2) The first charge capacity of the battery is improved;
3) The gel time of the slurry is prolonged.
In a fourth aspect, the invention provides a lithium ion battery positive electrode, which comprises the modified positive electrode lithium supplement material.
In at least one embodiment of the present invention, the lithium ion battery positive electrode is formed by mixing, by mass, 8:1:1, carbon black and PVDF.
In at least one other embodiment of the present invention, the lithium ion battery positive electrode is formed by mixing, by mass, 8:1:1, carbon black and PVDF, wherein the mass percentage of the modified anode lithium supplement material in the mixture of the modified anode lithium supplement material and the lithium iron phosphate is 5%.
In a fifth aspect, the present invention provides a lithium ion battery, which comprises any one of the modified positive electrode lithium supplement material or the lithium ion battery positive electrode.
In at least one embodiment of the present invention, the lithium ionsThe battery is a button battery, the negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with 1mol/L 6 The electrolyte solvent is EC, DMC and EMC with the volume ratio of 1.
The invention has the following beneficial effects: the invention designs a surface coating layer to coat the lithium-rich oxide of the lithium-supplement material of the anode, (1) polyalkylene oxide is uniformly coated on the surfaces of lithium-rich oxide particles by a chemical vapor deposition method and effective cross-linking is formed among the particles, and 3D high-efficiency Li is constructed + A transmission network is used for improving the capacity; (2) Effectively isolating the lithium-rich oxide from contacting with moisture in the air, reducing surface alkali residue, improving the structural stability of the lithium-rich oxide, obviously prolonging the coating window period during processing and effectively improving the problem of slurry gelation. (3) Due to the hydrophobic oleophylic characteristic of the coating layer, the lithium supplement additive has excellent matching degree with the traditional oil-based adhesive, is more uniformly and tightly contacted with a positive electrode material, and has obvious effect of improving the capacity of a battery.
Drawings
FIG. 1 is SEM pictures of example 1 (a) and comparative example 3 (b).
Detailed Description
The present invention is described in further detail below with reference to specific embodiments, which are given for the purpose of illustration only and are not intended to limit the scope of the invention. The examples provided below serve as a guide for further modifications by a person skilled in the art and do not constitute a limitation of the invention in any way.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; the materials, reagents and the like used are commercially available unless otherwise specified.
Example 1
Mixing lithium-rich lithium iron oxide (Li) 5 FeO 4 ) Soaking in anhydrous ethanol, ultrasonic treating in an ultrasonic cleaning machine with ultrasonic power of 80W for 60min, sufficiently washing off alkaline impurities on the surface and adding Li 5 FeO 4 Forming a rough layer on the surface, and baking in a vacuum drying oven (vacuum degree-0.05 MPa) at 80 ℃ for 8h to obtain surface-treated Li 5 FeO 4 And (3) particles.
5g of the purified Li 5 FeO 4 Placing the particles (average diameter of 5 μm) and 0.5g of polydimethylsiloxane (molecular weight of 2500) in a high temperature-resistant sealable container, introducing nitrogen, and treating at 300 deg.C for 2 hr to obtain polydimethylsiloxane 5 FeO 4 The surface is slowly self-assembled and deposited to form the coating modified Li 5 FeO 4 The thickness of the coating layer of the composite material is 0.5 mu m.
Coating the prepared modified Li 5 FeO 4 The material, carbon black and PVDF are mixed according to the proportion of 8:1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Coating the prepared modified Li 5 FeO 4 Mixing the material with a lithium iron phosphate positive electrode material according to a mass ratio of 5: 1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The measuring voltage range of the button cell is 2V-4.5V, and the charging and discharging current is 0.05C.
Example 2
Lithium-rich lithium ferrate (Li) 5 FeO 4 ) Soaking in anhydrous methanol, ultrasonic treating in ultrasonic cleaner at 200W for 15min to remove alkaline impurities on surface and Li 5 FeO 4 Forming a rough layer on the surface, placing the rough layer in a vacuum drying oven (vacuum degree of-0.09 MPa) at 120 ℃ for baking for 16h to obtain surface-treated Li 5 FeO 4 And (3) granules.
5g of the purified Li obtained 5 FeO 4 The particles (average diameter 3 μm) and 0.2g of polymethylphenylsiloxane (molecular weight 2700) were placed in a heat-resistant sealable container, treated at 200 ℃ for 1h with nitrogen, and the polymethylphenylsiloxane was dried in Li 5 FeO 4 The surface is slowly self-assembled and deposited to form the coating modified Li 5 FeO 4 The thickness of the coating layer of the composite material is 0.1 mu m.
Coating the prepared modified Li 5 FeO 4 The material is mixed with carbon black and PVDF according to the proportion of 8:1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Coating the prepared modified Li 5 FeO 4 Mixing the material with a lithium iron phosphate positive electrode material according to a mass ratio of 5: 1:1, then coating the aluminum foil as the anode of the lithium ion battery by scraping, and assembling a button cell with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Example 3
Mixing lithium-rich lithium nickelate (Li) 2 NiO 2 ) Soaking in acetonitrile, ultrasonic treating in ultrasonic cleaner at 200W for 30min to remove alkaline impurities on surface and Li 2 NiO 2 Forming a rough layer on the surface, placing the rough layer in a vacuum drying oven (vacuum degree of-0.09 MPa) at 120 ℃ for baking for 24 hours to obtain surface-treated Li 2 NiO 2 And (3) granules.
5g of the purified Li obtained 2 NiO 2 Particles (average diameter 2 μm) were mixed with 0.1g of polyphenylmethylsiloxane (molecular weight 250)0) Placing into a high temperature resistant sealable container, introducing argon, and treating at 250 deg.C for 1 hr to make polyphenylsiloxane in Li 2 NiO 2 The surface is slowly self-assembled and deposited to form the coating modified Li 2 NiO 2 The thickness of the coating layer of the composite material is 0.2 mu m.
Li coated with prepared super-hydrophobic layer 2 NiO 2 The material is mixed with carbon black and PVDF according to the proportion of 8:1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Coating the prepared modified Li 2 NiO 2 Mixing the material with a lithium iron phosphate positive electrode material according to a mass ratio of 5: 1:1, then coating the aluminum foil as the anode of the lithium ion battery by scraping, and assembling a button cell with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Example 4
Mixing lithium-rich lithium nickelate (Li) 2 NiO 2 ) Soaking in isopropanol, placing in an ultrasonic cleaning machine, performing ultrasonic treatment for 30min with ultrasonic power of 100W, sufficiently washing off alkaline impurities on the surface and in Li 2 NiO 2 Forming a rough layer on the surface, placing the rough layer in a vacuum drying oven (vacuum degree is-0.09 MPa) at 80 ℃ for baking for 24 hours to obtain the surface-treated Li 2 NiO 2 And (3) granules.
5g of the purified Li 2 NiO 2 Placing the particles (average diameter of 8 μm) and 0.5g polymethylphenylsiloxane (molecular weight of 2700) in a heat-resistant sealable container, introducing argon, and treating at 250 deg.C for 1 hr to obtain polyMethylphenylsiloxane in Li 2 NiO 2 The surface is slowly self-assembled and deposited to form the coating modified Li 2 NiO 2 The thickness of the coating layer of the composite material is 0.6 mu m.
Coating the prepared modified Li 2 NiO 2 The material is mixed with carbon black and PVDF according to the proportion of 8:1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Coating the prepared modified Li 2 NiO 2 Mixing the material with a lithium iron phosphate positive electrode material according to a mass ratio of 5: 1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Example 5
Mixing lithium-rich lithium cobaltate (Li) 6 CoO 4 ) Soaking in isopropanol, ultrasonic treating in ultrasonic cleaner at 150W for 50min to remove alkaline impurities on surface and Li 6 CoO 4 Forming a rough layer on the surface, placing the rough layer in a vacuum drying oven (vacuum degree of-0.02 MPa) at 120 ℃ for baking for 24 hours to obtain surface-treated Li 6 CoO 4 And (3) granules.
5g of the purified Li obtained 6 CoO 4 Placing the particles (average diameter of 1 μm) and 0.5g polymethylphenylsiloxane (molecular weight of 2700) in a high temperature-resistant sealable container, introducing argon, and treating at 250 deg.C for 2 hr to make polyphenylmethylsiloxane in Li 6 CoO 4 The surface is slowly self-assembled and deposited to form a packageLi coated with modification 6 CoO 4 The thickness of the coating layer of the composite material is 0.1 mu m.
Coating the prepared modified Li 6 CoO 4 The material is mixed with carbon black and PVDF according to the proportion of 8:1:1, then coating the aluminum foil as the anode of the lithium ion battery by scraping, and assembling a button cell with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Coating the prepared modified Li 6 CoO 4 Mixing the material with a lithium iron phosphate positive electrode material according to a mass ratio of 5: 1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Comparative example 1
5g of Li 5 FeO 4 Placing the particles (average diameter of 5 μm) and 0.5g of polydimethylsiloxane (molecular weight of 2500) in a high temperature-resistant sealable container, introducing nitrogen, and treating at 300 deg.C for 2 hr to obtain polydimethylsiloxane 5 FeO 4 Slow self-assembly of the surface, deposition to form Li 5 FeO 4 A composite material.
In this comparative example, li 5 FeO 4 The surface is not treated, and a uniform and complete coating layer cannot be formed.
The prepared Li 5 FeO 4 The material is mixed with carbon black and PVDF according to the proportion of 8:1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, and the diaphragm is a polypropylene microporous membraneThe electrolyte is a 1mol/L LiPF6 solution, and the electrolyte solvent is EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
The prepared Li 5 FeO 4 Mixing the material with a lithium iron phosphate positive electrode material according to a mass ratio of 5: 1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Comparative example 2
Mixing lithium-rich lithium iron oxide (Li) 5 FeO 4 ) Soaking in anhydrous ethanol for 60min, and baking in 80 deg.C vacuum drying oven (vacuum degree-0.05 MPa) for 8 hr to obtain surface treated Li 5 FeO 4 And (3) granules.
5g of the purified Li obtained 5 FeO 4 Placing the particles (average diameter of 5 μm) and 0.5g of polydimethylsiloxane (molecular weight of 2500) in a high temperature-resistant sealable container, introducing nitrogen, and treating at 300 deg.C for 2 hr to obtain polydimethylsiloxane 5 FeO 4 Slow self-assembly of the surface, deposition to form Li 5 FeO 4 The thickness of the coating layer of the composite material is 0.5 mu m.
The prepared Li 5 FeO 4 The material, carbon black and PVDF are mixed according to the proportion of 8:1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
The prepared Li 5 FeO 4 The mass of the material and the lithium iron phosphate anode material is 5After mixing, mixing the mixture with carbon black and PVDF according to the proportion of 8:1:1, then coating the aluminum foil as the anode of the lithium ion battery by scraping, and assembling a button cell with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Comparative example 3
Lithium-rich lithium ferrate (Li) 5 FeO 4 ) Soaking in anhydrous ethanol, ultrasonic treating in an ultrasonic cleaner at 80W for 60min to remove alkaline impurities on surface and Li 5 FeO 4 Forming a rough layer on the surface, and baking in a vacuum drying oven (vacuum degree-0.05 MPa) at 80 ℃ for 8h to obtain surface-treated Li 5 FeO 4 And (3) particles.
5g of the purified Li obtained 5 FeO 4 The particles (average diameter 5 μm) were placed in a high temperature-resistant sealable container, nitrogen was passed through, and the mixture was treated at 300 ℃ for 2 hours.
The prepared Li 5 FeO 4 The material is mixed with carbon black and PVDF according to the proportion of 8:1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The electrolyte solvent was EC: DMC: EMC = 1. The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
The prepared Li 5 FeO 4 Mixing the material with a lithium iron phosphate positive electrode material according to a mass ratio of 5: 1:1, then coating the aluminum foil by scraping to be used as the anode of the lithium ion battery, and assembling the button cell battery with the model of CR2032 in a glove box filled with argon. The negative electrode of the battery is a metal lithium sheet, the diaphragm is a polypropylene microporous membrane, and the electrolyte is LiPF with the concentration of 1mol/L 6 The solution of the electrolyte solvent is EC, DMC and EMC =1 (v/v/v). The button cell has a voltage measuring range of 2V-4.5V and a charge-discharge current of 0.05C.
Comparative example 4
0.5g of polydimethylsiloxane (molecular weight: 2500) was dispersed in 10mL of anhydrous ethanol, and 5g of Li was added 5 Adding FeO4 powder into the mixture, fully stirring for 5h to be uniform, filtering, washing with 10mL of absolute ethanol, heating at 60 ℃ to volatilize the solvent, and finally drying in a vacuum oven at 100 ℃ for 12h to remove the residual solvent to obtain the composite material.
The SEM pictures of example 1 and comparative example 3 are shown in fig. 1, and it can be seen from fig. 1 that the surface roughness is increased and the degree of cross-linking between particles is significantly increased after example 1 is coated with polysiloxane compared to comparative example 3.
Physicochemical and electrical properties of the positive electrode lithium-doped materials prepared in the above experimental examples 1 to 5 and comparative examples 1 to 3 were measured, and the results are shown in table 1.
The test method is as follows:
residual alkali LiOH test method: accurately weighing 0.3g of sample in a 100ml clean and dry gas washing bottle, adding 100ml of ethanol with fixed volume into the gas washing bottle, and stirring for 5min. After the stirring, the mixture was vacuum filtered, and the filtrate was collected in a 100ml volumetric flask. Transferring 40ml of filtrate and adding into a titration cup; titration with 0.01M HCl standard solution gave a titration curve and the volume V1 of hydrochloric acid standard solution consumed in the process was recorded. While the analytical method is blank, end point consumed hydrochloric acid volume V0, liOH content =23.94 × 0.01 × (V1-V0)/120.
Gel time determination method: the prepared Li 5 FeO 4 The material is mixed with carbon black and PVDF according to the proportion of 8:1:1, wherein the PVDF is a dope solution in which PVDF having a mass concentration of 5% is dispersed in NMP. The mixture was placed in a pulper and dispersed at 1950rmp for 10min before being removed. And starting timing when the slurry is taken out, and stopping timing when the glue solution is completely condensed into jelly without fluidity, wherein the time duration is the slurry gelling time. The experimental test conditions were a temperature of 25 ℃ and a dew point of-30 ℃.
TABLE 1 test results of positive electrode lithium-supplement materials
| Sample (I) | Residual alkali (LiOH) | First charge capacity of anode lithium supplement material | Gel time of the slurry |
| Example 1 | 220ppm | 622.3mAh/g | 400min |
| Example 2 | 312ppm | 608.9mAh/g | 315min |
| Example 3 | 488ppm | 386.0mAh/g | 205min |
| Example 4 | 431ppm | 365.6mAh/g | 200min |
| Example 5 | 189ppm | 855.7mAh/g | 465min |
| Comparative example 1 | 1165ppm | 597.7mAh/g | 12min |
| Comparative example 2 | 976ppm | 567.9mAh/g | 36min |
| Comparative example 3 | 1808ppm | 564.8mAh/g | 4min |
| Comparative example 4 | 877ppm | 467.9mAh/g | 40min |
As can be seen from Table 1, examples 1 to 5 showed a significant decrease in the residual alkali LiOH content as compared with comparative examples 1 to 4. Wherein examples 1,2 and comparative examples 1 to 4 are compared, and Li is coated after modification 5 FeO 4 The initial charge capacity of the material is improved, and compared with comparative examples 1 to 4, the gel time of the slurry is greatly prolonged in examples 1 to 5, which shows that high-efficiency Li is formed after polysiloxane coating + The transmission network can effectively improve the capacity exertion, the residual alkali value is reduced after the surface is coated, and the gel time of the slurry is obviously prolonged.
In order to further evaluate the lithium supplementing effect of the positive electrode lithium supplementing material prepared by the method, the lithium supplementing material is added into the lithium iron phosphate positive electrode material in a mass ratio of 5%, and electricity is generated by mixing and coating. Table 2 shows the performance of the electrical properties of the lithium supplement material added to the cathode material. The test method is the same as above.
TABLE 2 test results of 5% lithium supplement material + lithium iron phosphate
| Sample(s) | Initial charge capacity of 5% lithium supplement material and lithium iron phosphate | Gel time of the slurry |
| Example 1 | 183.9mAh/g | 585min |
| Example 2 | 180.7mAh/g | 470min |
| Example 3 | 172.5mAh/g | 335min |
| Example 4 | 171.2mAh/g | 335min |
| Example 5 | 191.3mAh/g | 525min |
| Comparative example 1 | 173.1mAh/g | 20min |
| Comparative example 2 | 174.6mAh/g | 30min |
| Comparative example 3 | 173.6mAh/g | 8min |
| Comparative example 4 | 171.0mAh/g | 23min |
As can be seen from Table 1, in examples 1 and 2, compared with comparative examples 1 to 4, the gel time of the slurry is greatly improved, and the first charge capacity is also improved, which shows that the polysiloxane coating of the lithium supplement material is beneficial to promoting the uniform dispersion of the material in the slurry and enhancing the effect.
The present invention has been described in detail above. It will be apparent to those skilled in the art that the present invention may be practiced in a wide range of equivalent parameters, concentrations, and conditions without departing from the spirit or scope of the invention. While the invention has been described with reference to specific embodiments, it will be appreciated that the invention can be further modified. In general, this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains.
Claims (10)
1. A modified positive electrode lithium supplement material is characterized in that: the lithium-rich lithium-ion battery comprises lithium-rich oxide particles and a coating layer which is coated on the surfaces of the lithium-rich oxide particles and is made of polysiloxane compounds;
the lithium-rich oxide particles are Li 5 FeO 4 、Li 6 CoO 4 And Li 2 NiO 2 Any one of (a);
the polysiloxane compound is selected from any one of polydimethylsiloxane, polymethylphenylsiloxane and polyphenylmethylsiloxane;
wherein the polysiloxane compound is cross-linked between the lithium-rich oxide particles.
2. The modified positive electrode lithium supplement material according to claim 1, wherein: the mass ratio of the polysiloxane compound to the lithium-rich oxide particles is (0.01-0.10): 1;
the thickness of the coating layer is 0.1-1.0 μm.
3. The modified positive electrode lithium supplement material according to claim 1 or 2, characterized in that: the lithium-rich oxide particles have an average diameter of 0.5 to 10 μm.
4. The modified positive electrode lithium supplement material according to claim 1 or 2, wherein: the molecular weight of the polydimethylsiloxane is 1000-5000;
the molecular weight of the polymethylphenylsiloxane is 1000-3000;
the molecular weight of the polyphenyl methyl siloxane is 2000-5000.
5. The method for preparing the modified positive electrode lithium supplement material according to any one of claims 1 to 4, comprising the steps of:
s1, placing the lithium-rich oxide particles in an organic solvent for ultrasonic treatment, and drying after the ultrasonic treatment;
and S2, taking the polysiloxane compound as a deposition material, and carrying out chemical vapor deposition on the lithium-rich oxide particles treated in the step S1 under the protection of inert atmosphere to form the coating layer, so as to obtain the modified cathode lithium supplement material.
6. The method for preparing the modified positive electrode lithium supplement material according to claim 5, wherein: the organic solvent is any one of absolute ethyl alcohol, absolute methyl alcohol, isopropanol, acetonitrile and acetone;
the power of ultrasonic treatment is 80-200W, and the time is 15-60 min;
the drying temperature is 60-120 ℃, the drying time is 8-24 h, and the vacuum degree is less than or equal to-0.02 MPa.
7. The method for preparing the modified positive electrode lithium supplement material according to claim 5, wherein: the temperature of the chemical vapor deposition is 200-300 ℃, and the time is 0.5-5 h.
8. Use of the modified positive electrode lithium supplement material of any one of claims 1 to 4 in any one of the following 1) to 3):
1) Reducing the content of residual alkali LiOH on the surface;
2) The first charge capacity of the battery is improved;
3) The gel time of the slurry is prolonged.
9. A lithium ion battery positive electrode, characterized in that: it comprises the modified positive electrode lithium supplement material according to any one of claims 1 to 4.
10. A lithium ion battery, characterized by: the modified positive electrode lithium supplement material of any one of claims 1 to 4 or the lithium ion battery positive electrode of claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310111395.1A CN115911366A (en) | 2023-02-01 | 2023-02-01 | Modified positive electrode lithium supplement material, lithium ion battery positive electrode and lithium ion battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310111395.1A CN115911366A (en) | 2023-02-01 | 2023-02-01 | Modified positive electrode lithium supplement material, lithium ion battery positive electrode and lithium ion battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115911366A true CN115911366A (en) | 2023-04-04 |
Family
ID=86479171
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310111395.1A Pending CN115911366A (en) | 2023-02-01 | 2023-02-01 | Modified positive electrode lithium supplement material, lithium ion battery positive electrode and lithium ion battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115911366A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116666582A (en) * | 2023-05-16 | 2023-08-29 | 广州凌顶能源科技有限公司 | Metal oxide coated lithium oxide composite positive electrode material, preparation method thereof, positive electrode plate containing positive electrode material and battery |
| CN117117357A (en) * | 2023-10-25 | 2023-11-24 | 宁德时代新能源科技股份有限公司 | Lithium supplementing agent, preparation method thereof, positive electrode plate, battery and power utilization device |
| CN117558922A (en) * | 2024-01-12 | 2024-02-13 | 紫金矿业新能源新材料科技(长沙)有限公司 | Lithium-rich lithium ferrite lithium supplementing material and preparation method thereof |
-
2023
- 2023-02-01 CN CN202310111395.1A patent/CN115911366A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116666582A (en) * | 2023-05-16 | 2023-08-29 | 广州凌顶能源科技有限公司 | Metal oxide coated lithium oxide composite positive electrode material, preparation method thereof, positive electrode plate containing positive electrode material and battery |
| CN117117357A (en) * | 2023-10-25 | 2023-11-24 | 宁德时代新能源科技股份有限公司 | Lithium supplementing agent, preparation method thereof, positive electrode plate, battery and power utilization device |
| CN117117357B (en) * | 2023-10-25 | 2024-03-12 | 宁德时代新能源科技股份有限公司 | Lithium supplementing agent, preparation method thereof, positive electrode plate, battery and power utilization device |
| CN117558922A (en) * | 2024-01-12 | 2024-02-13 | 紫金矿业新能源新材料科技(长沙)有限公司 | Lithium-rich lithium ferrite lithium supplementing material and preparation method thereof |
| CN117558922B (en) * | 2024-01-12 | 2024-03-29 | 紫金矿业新能源新材料科技(长沙)有限公司 | Lithium-rich lithium ferrite lithium supplementing material and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN115911366A (en) | Modified positive electrode lithium supplement material, lithium ion battery positive electrode and lithium ion battery | |
| CN103730645B (en) | Coated carbon fiber nanometer composite material of a kind of silicon and its preparation method and application | |
| CN110739427B (en) | Battery diaphragm material and preparation method and application thereof | |
| CN102104144B (en) | Method for preparing lithium iron phosphate compound anode material | |
| CN102723491A (en) | Lithium ion battery combined electrode material immersed and covered by conducting polymer and preparation method thereof | |
| CN109449399B (en) | Hollow hybrid microsphere for lithium ion battery negative electrode material and preparation method thereof | |
| CN109659511B (en) | SiO (silicon dioxide)2Coated ternary positive electrode material and preparation method thereof | |
| CN115566255B (en) | Secondary battery and electric equipment | |
| CN111029547A (en) | Preparation method of porous silicon-carbon composite material | |
| CN103050694A (en) | Anode active material, preparation method thereof and battery | |
| CN114751393A (en) | Nitrogen-sulfur co-doped porous carbon/sulfur composite material and preparation method and application thereof | |
| CN114171736B (en) | Water-based lithium manganate positive electrode slurry and preparation method thereof | |
| CN111584866A (en) | Preparation method of high-rate artificial graphite negative electrode material | |
| CN113690420B (en) | Nitrogen-sulfur doped silicon-carbon composite material and preparation method and application thereof | |
| CN107634177A (en) | A kind of LiFePO4 combination electrode of surface metal oxide coating | |
| CN107742694B (en) | Silicon-based negative electrode plate, silicon-doped composite current collector and lithium ion battery | |
| CN112467117B (en) | Lithium titanium aluminum phosphate coated graphite composite material, preparation method thereof and battery cathode | |
| CN113889595A (en) | Preparation method of solid electrolyte coated graphite composite material | |
| CN116364886A (en) | Silicon-mesoporous titanium dioxide composite anode material, preparation method and battery | |
| CN109309228B (en) | Positive electrode active material, preparation method, positive electrode and high-specific-energy power battery | |
| CN115020708A (en) | Water-based binder suitable for negative electrode and preparation method and application thereof | |
| CN114695894A (en) | High-capacity hard carbon fast-charging negative electrode material and preparation method and application thereof | |
| CN114864897A (en) | Quick-charging graphite composite material and preparation method thereof | |
| CN110518194B (en) | Method for preparing core-shell silicon/carbon composite material by in-situ carbon coating and application thereof | |
| CN108807921B (en) | Lithium battery negative electrode material and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |