CN116314820A - Positive electrode lithium supplementing additive and preparation method thereof - Google Patents
Positive electrode lithium supplementing additive and preparation method thereof Download PDFInfo
- Publication number
- CN116314820A CN116314820A CN202310349895.9A CN202310349895A CN116314820A CN 116314820 A CN116314820 A CN 116314820A CN 202310349895 A CN202310349895 A CN 202310349895A CN 116314820 A CN116314820 A CN 116314820A
- Authority
- CN
- China
- Prior art keywords
- lithium
- acid
- supplementing
- positive electrode
- organic
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
-
- 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
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention provides a positive electrode lithium supplementing additive and a preparation method thereof, and belongs to the technical field of preparation of lithium battery additives. The positive electrode lithium supplementing additive comprises a lithium supplementing agent core and an organic acid salt shell coated on the surface of the lithium supplementing agent; the organic acid salt shell is formed by in-situ conversion of residual alkali on the surface of the lithium supplementing agent and organic acid through reaction; the size of the lithium supplementing agent core is 1-20 mu m, and the thickness of the organic acid salt shell is 10-30 nm. The positive electrode lithium supplementing additive provided by the invention has the advantages of low residual alkali amount, good air stability and good conductivity.
Description
Technical Field
The invention belongs to the technical field of preparation of lithium battery additives, and particularly relates to a positive electrode lithium supplementing additive and a preparation method thereof.
Background
Most lithium batteries with high specific capacity lose a large amount of active lithium due to the formation of an SEI film during the first charge and discharge, and the loss of the active lithium in the positive electrode material can lead to permanent loss of lithium, thereby reducing the battery capacity, reducing the coulombic efficiency and deteriorating the cycle performance. The lithium supplementing technique is an effective means for improving the above problems. The lithium supplementing method can be divided into two types of negative electrode lithium supplementing and positive electrode lithium supplementing according to the technical route. The negative electrode lithium supplementing mode is simple and efficient, but is limited by the safety risk and the process difficulty of the metal lithium, and the negative electrode lithium supplementing technology still cannot be applied on a large scale. The lithium supplementing material is added into the positive electrode of the lithium ion battery, so that the lithium supplementing material is decomposed to release active lithium in the charging process of the battery, and the irreversible active lithium loss caused by the growth of the negative electrode SEI is compensated. The positive electrode lithium supplementing material has the advantages of stable chemical property, easiness in synthesis, low price, high lithium supplementing capability and the like, and meanwhile, the positive electrode lithium supplementing process can be well compatible with the existing lithium ion battery manufacturing process, and is more suitable for industrialization compared with the negative electrode lithium supplementing process.
The types of the currently reported positive electrode lithium supplementing agents are various, such as Li 3 N、Li 2 S、Li 2 NiO 2 、Li 5 FeO 4 、Li 2 MnO 2 Etc., wherein Li 5 FeO 4 As a lithium-rich transition metal oxide, it has a purity of up to 867 mAh.g -1 The theoretical charge specific capacity of (2) is extremely low, the discharge specific capacity is extremely high, and the lithium supplementing capacity is extremely high, so that the active lithium loss generated by the formation of the SEI film can be compensated to the greatest extent. But also has poor air stability and is easy to be matched with H in the air 2 O、CO 2 The reaction is modified, the content of residual alkali on the surface is high, the homogenization process is unstable, the polarization is large, and the side reaction with electrolyte causes abnormal gas production, poor electric conductivity and the like.
In the prior art, a hydrophobic coating layer is generally introduced to isolate the reaction of the lithium supplementing material with external moisture and carbon dioxide, so that the air stability of the material is improved. However, residual alkali still exists in the material, and contacts with electrolyte when the battery works, so as to catalyze side reactions of the electrolyte, increase gas production and deteriorate battery performance. And most coating schemes need secondary high-temperature treatment, so that the preparation of the lithium supplementing agent with small particle size is not facilitated while the energy consumption is high.
Disclosure of Invention
The invention provides a positive electrode lithium supplementing additive and a preparation method thereof.
In order to achieve the aim, the invention provides a positive electrode lithium supplementing additive, which comprises a lithium supplementing agent core and an organic acid salt shell coated on the surface of the lithium supplementing agent core; the organic acid salt shell is formed by in-situ conversion of residual alkali on the surface of the lithium supplementing agent and organic acid through reaction; the size of the lithium supplementing agent core is 1-20 mu m, and the thickness of the organic acid salt shell is 10-30 nm.
Preferably, the residual alkali on the surface of the lithium supplementing agent comprises lithium carbonate and/or lithium hydroxide; the residual alkali content of the positive electrode lithium supplementing additive is less than or equal to 0.5wt%.
Preferably, the organic acid is one or more of organic sulfonic acid, organic boric acid, organic silicic acid, organic phosphoric acid and organic hypophosphorous acid; the lithium supplementing agent is Li 5 FeO 4 。
Preferably, the organic acid is one or more of trifluoromethanesulfonic acid, dodecylbenzenesulfonic acid, fluorobenzeneboronic acid, cyclopropylboric acid, formylphenylboric acid, 2-carboxyphenylboric acid, aminomethylphosphoric acid, dodecylphosphoric acid and 2-carboxyethylphenylphosphinic acid.
The invention provides a preparation method of the positive electrode lithium supplementing additive, which comprises the following steps:
1) Dissolving an iron source and a lithium source in water to prepare colloid, and spray-drying to prepare precursor powder;
2) Calcining the precursor powder in a vacuum environment to obtain a lithium supplementing material;
3) And mixing the lithium supplementing material, the organic acid and the molecular sieve for reaction, removing the molecular sieve after the reaction is completed, and drying to obtain the positive electrode lithium supplementing additive.
Preferably, the iron source in step 1) comprises one or more of iron oxide, hydroxide, sulfate, chlorate and nitrate; the lithium source comprises one or more of lithium oxide, hydroxide, peroxide, inorganic salt and organic salt.
Preferably, the spray drying temperature in step 1) is 180-200 ℃ and the feed flow rate is 20-25 mL/min.
Preferably, the degree of vacuum in step 2) upon calcination in a vacuum atmosphere is 1X 10 -5 Pa; the temperature during calcination is 700-950 ℃ and the time is 1-5 h.
Preferably, the molecular sieve in step 3) is a type 5A molecular sieve; the grain diameter of the molecular sieve is more than or equal to 0.5mm.
Preferably, the mixing in step 3) is solid phase mixing or liquid phase mixing; the solid phase mixing comprises one or more of grinding mixing, ball milling mixing and wall breaking machine mixing; the solvent used for liquid phase mixing comprises one or more of dichloromethane, chloroform, dimethylformamide, ethanol, acetone, tetrahydrofuran and N-methylpyrrolidone.
Compared with the prior art, the invention has the advantages and positive effects that:
(1) The positive electrode lithium supplementing additive provided by the invention adopts the reaction of the organic acid and the residual alkali on the surface of the lithium supplementing agent to enable the residual alkali on the surface to be in situ converted into organic acid salt components beneficial to a battery system, and simultaneously enables the residual alkali to be in situ converted into an organic acid salt coating layer, thereby reducing the residual alkali content on the surface of the lithium supplementing agent, improving the purity of the material, and improving the problems of difficult homogenate coating, low conductivity, aggravated electrolyte side reaction and the like caused by high residual alkali.
(2) The compact and uniform organic acid salt coating layer is formed in the invention, so that the reaction of the inner core of the lithium supplementing agent with moisture and carbon dioxide can be effectively isolated, the air stability of the lithium supplementing agent is improved, and the storage, transportation and processing performances are improved.
(3) The organic acid salt coating layer has good stability, can inhibit adverse reaction of materials and electrolyte, and can be used as an electrolyte additive after lithium supplementation is completed, so that good lithium supplementing performance of the lithium supplementing material is ensured.
(4) Furthermore, the lithium supplementing agent is prepared by calcining under the vacuum condition, byproducts can be timely discharged under the vacuum condition, the high-speed forward reaction is promoted, the calcining time is shortened, the particle size is reduced, and the residual alkali is reduced.
Drawings
FIG. 1 is an SEM image of a positive electrode lithium-compensating additive prepared in example 1;
fig. 2 is a graph showing the lithium-supplementing capacity of the positive electrode lithium-supplementing additive prepared in example 1.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a positive electrode lithium supplementing additive, which comprises a lithium supplementing agent core and an organic acid salt shell coated on the surface of the lithium supplementing agent core; the organic acid salt shell is formed by in-situ conversion of residual alkali on the surface of the lithium supplementing agent and organic acid through reaction; the size of the lithium supplementing agent core is 1-20 mu m, and the thickness of the organic acid salt shell is 10-30 nm.
In the invention, the size of the lithium supplementing agent core is limited to 1-20 mu m, the thickness of the organic acid salt shell is limited to 10-30 nm, and the small particle size can effectively shorten the lithium ion diffusion path and improve the ion diffusion performance.
In the present invention, the residual alkali on the surface of the lithium supplementing agent preferably comprises lithium carbonate and/or lithium hydroxide; the residual alkali content of the positive electrode lithium supplementing additive is less than or equal to 0.5wt%. Residual alkali in the lithium supplementing agent can cause unstable homogenization process, large polarization, abnormal gas production caused by side reaction with electrolyte, poor electric conductivity and the like. The organic acid salt shell in the positive electrode lithium supplementing additive is formed by in-situ conversion of residual alkali on the surface of the lithium supplementing agent and organic acid, and the organic acid reacts with the residual alkali in the conversion process, so that the residual alkali content in the lithium supplementing agent is effectively reduced, and the performance of the lithium supplementing agent is improved.
In the invention, the organic acid is one or more of organic sulfonic acid, organic boric acid, organic silicic acid, organic phosphoric acid and organic hypophosphorous acid; more preferably one or more of trifluoromethanesulfonic acid, dodecylbenzenesulfonic acid, fluorobenzeneboronic acid, cyclopropylboronic acid, formylphenylboronic acid, 2-carboxyphenylboronic acid, aminomethylphosphoric acid, dodecylphosphoric acid and 2-carboxyethylphenylphosphinic acid. In the invention, the organic acid can react with residual alkali in the lithium supplementing agent, and the organic acid salt coating generated by the reaction can also be used as an electrolyte additive, so that the good lithium supplementing performance of the lithium supplementing material is further ensured.
In the present invention, the lithium supplementing agent is preferably Li 5 FeO 4 。
In the present invention, the organic acid salt is preferably at least one of organic sulfonate, organic borate, organic silicate, organic phosphate and organic hypophosphite; more preferably at least one of trifluoromethanesulfonate, alkylbenzenesulfonate, difluorooxalato borate, bisoxalato borate, fluorobenzene borate, tetraethyltetrafluoroborate, cyclopropyl borate, acyl benzene borate, carboxybenzene borate, tetrafluorooxalato phosphate, difluorodioxaoxalato phosphate, aminomethyl phosphate, alkyl phosphate, trimethylsilane phosphate and ethylphenyl hypophosphite.
The positive electrode lithium supplementing additive provided by the invention adopts the reaction of organic acid and residual alkali on the surface of a lithium supplementing agent to enable the residual alkali on the surface to be converted into a compact organic acid salt coating layer in situ. On one hand, the content of residual alkali on the surface of the lithium supplementing agent is reduced, the purity of the material is improved, and the problems of difficult homogenization, low conductivity and the like caused by high residual alkali are solved; in the second aspect, the compact and uniform organic acid salt coating layer on the surface of the lithium supplementing agent can effectively isolate the reaction between the inner core of the lithium supplementing agent and moisture and carbon dioxide, improve the air stability of the lithium supplementing agent and improve the storage, transportation and processing performances; in the third aspect, the organic acid salt coating layer has good stability, can inhibit adverse reaction of materials and electrolyte, and can be used as an electrolyte additive after lithium supplementation is completed, so that good lithium supplementing performance of the lithium supplementing material is ensured.
The invention provides a preparation method of the positive electrode lithium supplementing additive, which comprises the following steps:
1) Dissolving an iron source and a lithium source in water to prepare colloid, and spray-drying to prepare precursor powder;
2) Calcining the precursor powder in a vacuum environment to obtain a lithium supplementing material;
3) And mixing the lithium supplementing material, the organic acid and the molecular sieve for reaction, removing the molecular sieve after the reaction is completed, and drying to obtain the positive electrode lithium supplementing additive.
The invention prepares precursor powder by dissolving an iron source and a lithium source in water to prepare colloid and spray-drying. In the present invention, the iron source preferably includes one or more of an oxide, hydroxide, sulfate, chlorate and nitrate of iron; more preferably Fe 2 O 3 、Fe 3 O 4 、FeC 2 O 4 、Fe(NO 3 ) 3 ·9H 2 O、FeCl 3 Or FeSO 4 The method comprises the steps of carrying out a first treatment on the surface of the Most preferably Fe (NO) 3 ) 3 ·9H 2 O. In the present invention, the lithium source preferably includes one or more of an oxide, hydroxide, peroxide, inorganic salt, and organic salt of lithium; more preferably Li 2 O、LiOH、Li 2 CO 3 、LiNO 3 、Li 2 C 2 O 4 And CH (CH) 3 One or more of COOLi; most preferably LiNO 3 。
In the present invention, the spray-drying temperature is preferably 180 to 200℃and the feed flow rate is preferably 20 to 25mL/min. According to the invention, the precursor is dried in a spray mode, and the obtained precursor has small particle size and narrow distribution range, so that the lithium supplementing material with small particle size is obtained.
After the precursor powder is obtained, the precursor powder is calcined in a vacuum environment to obtain the lithium supplementing material. In the present invention, the degree of vacuum upon calcination in a vacuum atmosphere is preferably 1X 10 -5 Pa; the temperature during calcination is preferably 700 to 950 ℃, and the time is preferably 1 to 5 hours. According to the invention, the calcination is carried out under the vacuum condition, so that harmful components in the atmosphere can be rapidly reduced, and the calcination time is shortened, thereby obtaining a loose and non-agglomerated lithium supplementing material, and the sample particle size is small. Meanwhile, the calcination is carried out under the vacuum condition, so that byproducts can be timely discharged, the high-speed forward reaction is promoted, and the calcination is shortenedFiring time.
After the lithium supplementing material is obtained, the lithium supplementing material, the organic acid and the molecular sieve are mixed for reaction, the molecular sieve is removed after the reaction is completed, and the positive electrode lithium supplementing additive is obtained after drying. In the present invention, the mixing means is preferably solid phase mixing or liquid phase mixing; the solid phase mixing preferably comprises one or more of grinding mixing, ball milling mixing and wall breaking machine mixing; the solvent used for the liquid phase mixing preferably comprises one or more of dichloromethane, chloroform, dimethylformamide, ethanol, acetone, tetrahydrofuran and N-methylpyrrolidone. In the present invention, the molecular sieve is preferably a type 5A molecular sieve; the particle size of the molecular sieve is preferably more than or equal to 0.5mm, more preferably 2-3 mm. In the present invention, molecular sieves are added for adsorbing H generated during the reaction 2 O. In the present invention, the drying mode is preferably 80 ℃ evaporation.
The technical solutions provided by the present invention are described in detail below in conjunction with examples for further illustrating the present invention, but they should not be construed as limiting the scope of the present invention.
Example 1
1. Preparation of the Positive electrode lithium-supplementing agent matrix
0.05mol of Fe (NO) 3 ) 3 ·9H 2 O is dissolved in 50ml deionized water to obtain ferric hydroxide colloid. Taking 0.2625mol LiNO 3 Dissolving in 50ml of water, and gradually dropwise adding into ferric hydroxide colloid to obtain precursor solution. Spray drying the precursor solution (drying temperature is 180deg.C, pressure is 0.3MPa, and feeding speed is 20 mL/min) to obtain precursor particles, and vacuum-drying the precursor particles in vacuum (vacuum degree is 1×10) -5 Pa), insulating at 850 ℃ for 3h, cooling along with a furnace to obtain Li 5 FeO 4 Particle diameter D 50 7.8 μm.
2. Preparation of positive electrode lithium supplementing additive coated with organic lithium sulfonate
0.063g of trifluoromethanesulfonic acid was weighed out and dissolved in 20mL of dimethylformamide, and 1g of Li obtained in step 1 was dissolved in water 5 FeO 4 Dispersing the lithium supplementing matrix and 0.5g of molecular sieve with the particle size of 2mm into the solution for reaction for 1h, and sieving to removeThe molecular sieve is filtered, leached for several times by dimethylformamide, and dried for 20min at 80 ℃ to obtain the positive electrode lithium supplementing additive, wherein an SEM (scanning electron microscope) diagram is shown in figure 1, and a lithium supplementing capacity performance diagram is shown in figure 2.
Example 2
1. Preparation of the Positive electrode lithium-supplementing agent matrix
0.05mol of Fe (NO) 3 ) 3 ·9H 2 O is dissolved in 20ml deionized water to obtain ferric hydroxide colloid. Taking 0.275mol LiNO 3 Dissolving in 20ml of water, and gradually dropwise adding into ferric hydroxide colloid to obtain precursor solution. Spray drying the precursor solution (drying temperature 200deg.C, pressure 0.3MPa, and feed rate 20 mL/min) to obtain precursor particles, and vacuum-drying the precursor particles in a vacuum environment (vacuum degree 1×10) -5 Pa), preserving the temperature for 2 hours at 900 ℃, and cooling along with a furnace to obtain Li 5 FeO 4 Particle diameter D 50 8.2 μm.
2. Preparation of positive electrode lithium supplementing additive coated with organic lithium hypophosphite
0.09g of 2-carboxyethylphenyl hypophosphorous acid was weighed out and dispersed in 20mL of tetrahydrofuran, after which 1g of Li obtained in step 1 was dissolved 5 FeO 4 Dispersing a lithium supplementing matrix and 0.5g of molecular sieve with the particle size of 2mm into the solution for reaction, sieving the molecular sieve after the reaction is carried out for 1.5h, filtering, leaching for several times by tetrahydrofuran, and drying for 20min at 80 ℃ to obtain the positive electrode lithium supplementing additive.
Example 3
1. Preparation of the Positive electrode lithium-supplementing agent matrix
0.05mol of Fe (NO) 3 ) 3 ·9H 2 O is dissolved in 50ml deionized water to obtain ferric hydroxide colloid. Taking 0.2625mol LiNO 3 Dissolving in 50ml of water, and gradually dropwise adding into ferric hydroxide colloid to obtain precursor solution. Spray drying the precursor solution (drying temperature is 180deg.C, pressure is 0.3MPa, and feeding speed is 20 mL/min) to obtain precursor particles, and vacuum-drying the precursor particles in vacuum (vacuum degree is 1×10) -5 Pa), insulating at 850 ℃ for 3h, cooling along with a furnace to obtain Li 5 FeO 4 Particle diameter D 50 7.8 μm.
2. Preparation of lithium supplementing additive for anode coated with lithium organic phosphate
0.105g of dodecylphosphoric acid was weighed and dissolved in 20mL of tetrahydrofuran, followed by 1g of Li obtained in the step one 5 FeO 4 Dispersing a lithium supplementing matrix and 0.5g of molecular sieve with the particle size of 2mm into the solution for reaction, sieving the molecular sieve after reacting for 1h, filtering, leaching with tetrahydrofuran for several times, and drying at 80 ℃ for 20min to obtain the positive electrode lithium supplementing additive.
Example 4
1. Preparation of the Positive electrode lithium-supplementing agent matrix
0.05mol of Fe (NO) 3 ) 3 ·9H 2 O is dissolved in 20ml deionized water to obtain ferric hydroxide colloid. Taking 0.275mol LiNO 3 Dissolving in 20ml of water, and gradually dropwise adding into ferric hydroxide colloid to obtain precursor solution. Spray drying the precursor solution (drying temperature 200deg.C, pressure 0.3MPa, and feed rate 20 mL/min) to obtain precursor particles, and vacuum-drying the precursor particles in a vacuum environment (vacuum degree 1×10) -5 Pa), preserving the temperature for 2 hours at 900 ℃, and cooling along with a furnace to obtain Li 5 FeO 4 Particle diameter D 50 8.2 μm.
2. Preparation of positive electrode lithium supplementing additive coated with organic lithium borate
0.059g of fluorobenzeneboronic acid is weighed and dissolved in 20mL of chloroform, and 1g of Li obtained in the step one is added 5 FeO 4 Dispersing a lithium supplementing matrix and 0.5g of molecular sieve with the particle size of 2mm into the solution for reaction, sieving the molecular sieve after reacting for 1h, filtering, leaching for several times by using chloroform, and drying for 20min at 80 ℃ to obtain the positive electrode lithium supplementing additive.
Comparative examples 1 to 2
Comparative examples 1 to 2 correspond in sequence to the uncoated lithium supplement matrices prepared in examples 1 to 2.
Comparative example 3
The difference from example 1 is that the lithium supplementing material is obtained by sintering a precursor under nitrogen atmosphere, and the specific operation is as follows:
1. preparation of the Positive electrode lithium-supplementing agent matrix
0.05mol of Fe (NO) 3 ) 3 ·9H 2 O is dissolved in 50ml deionized water to obtain hydrogen oxideIron colloid. Taking 0.2625mol LiNO 3 Dissolving in 50ml of water, and gradually dropwise adding into ferric hydroxide colloid to obtain precursor solution. Spray drying the precursor solution (drying temperature is 180 ℃, pressure is 0.3MPa, feeding speed is 20 mL/min) to obtain precursor particles, preserving heat for 5h at 850 ℃ in nitrogen atmosphere, and cooling along with a furnace to obtain Li 5 FeO 4 Particle diameter D 50 13.5 μm.
2. Preparation of positive electrode lithium supplementing additive coated with organic lithium hypophosphite
0.063g of trifluoromethanesulfonic acid was weighed out and dissolved in 20mL of dimethylformamide, and 1g of Li obtained in step 1 was dissolved in water 5 FeO 4 Dispersing a lithium supplementing matrix and 0.5g of molecular sieve with the particle size of 2mm into the solution, reacting for 1h, sieving the molecular sieve, filtering, leaching for several times by using dimethylformamide, and drying for 20min at 80 ℃ to obtain the positive electrode lithium supplementing additive.
Base number test
The positive electrode lithium supplement additive obtained in the examples and the comparative examples is dissolved in methanol according to the ratio of solid to liquid=1:20, the solid material is filtered after stirring for 10min, the filtrate is transferred into a titration cup, electrochemical titration is carried out by using 0.1M hydrochloric acid standard solution, and the addition of two jump points is taken as the total base number. The test results are shown in table 1:
TABLE 1 Total base number
| Residual alkali content (wt%) | |
| Example 1 | 0.12 |
| Example 2 | 0.25 |
| Example 3 | 0.26 |
| Example 4 | 0.19 |
| Comparative example 1 | 2.52 |
| Comparative example 2 | 2.98 |
| Comparative example 3 | 3.901 |
As can be seen from table 1, the coating of the organic acid salt has a significant improvement effect in reducing the base number of the lithium-compensating agent material, which is mainly due to the in-situ reaction of the organic acid and the residual base on the surface of the lithium-compensating agent. The lower base number of example 1 compared to comparative example 3 is mainly due to the reduced residual base content of the lithium supplement by vacuum sintering.
Air stability test
The lithium supplement additives prepared in each example and each comparative example were mixed with a conductive agent and a binder to prepare a pole piece, and the pole piece and the lithium piece were assembled into a half cell for testing, and stability data under an air atmosphere at 30 ℃ and humidity of 30% are shown in table 2:
TABLE 2 Capacity Retention Rate
| 24h capacity retention (%) | |
| Example 1 | 88.5 |
| Example 2 | 87.3 |
| Example 3 | 87.8 |
| Example 4 | 88.1 |
| Comparative example 1 | 52.4 |
| Comparative example 2 | 49.8 |
| Comparative example 3 | 84.1 |
As can be seen from table 2, the organic acid salt coating layer effectively improves the air stability of the lithium supplementing material.
Battery performance test
The products prepared in each example and each comparative example were mixed with NCM811, conductive carbon black, and PVDF as lithium supplementing additives in an amount of 3wt% based on the positive electrode active material, and homogenized to prepare a positive electrode sheet. The graphite was used as a negative electrode active material to prepare a negative electrode sheet, and the full cell was assembled for testing, and the data are shown in table 3 below:
table 3 battery performance
As can be seen from table 3, the positive electrode lithium-supplementing additive obtained by the preparation method of the present invention has more excellent lithium-supplementing effect.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (10)
1. The positive electrode lithium supplementing additive is characterized by comprising a lithium supplementing agent core and an organic acid salt shell coated on the surface of the lithium supplementing agent core; the organic acid salt shell is formed by in-situ conversion of residual alkali on the surface of the lithium supplementing agent and organic acid through reaction; the size of the lithium supplementing agent core is 1-20 mu m, and the thickness of the organic acid salt shell is 10-30 nm.
2. The positive electrode lithium supplement additive according to claim 1, wherein residual alkali on the surface of the lithium supplement agent comprises lithium carbonate and/or lithium hydroxide; the residual alkali content of the positive electrode lithium supplementing additive is less than or equal to 0.5wt%.
3. The positive electrode lithium-supplementing additive according to claim 1, wherein the organic acid is one or more of organic sulfonic acid, organic boric acid, organic silicic acid, organic phosphoric acid and organic hypophosphorous acid; the lithium supplementing agent is Li 5 FeO 4 。
4. The positive electrode lithium-supplementing additive according to claim 3, wherein the organic acid is one or more of trifluoromethanesulfonic acid, dodecylbenzenesulfonic acid, fluorobenzeneboronic acid, cyclopropylboronic acid, formylphenylboronic acid, 2-carboxyphenylboronic acid, aminomethylphosphoric acid, dodecylphosphoric acid and 2-carboxyethylphenylphosphinic acid.
5. The method for preparing a positive electrode lithium-supplementing additive according to any one of claims 1 to 4, comprising the steps of:
1) Dissolving an iron source and a lithium source in water to prepare colloid, and spray-drying to prepare precursor powder;
2) Calcining the precursor powder in a vacuum environment to obtain a lithium supplementing material;
3) And mixing the lithium supplementing material, the organic acid and the molecular sieve for reaction, removing the molecular sieve after the reaction is completed, and drying to obtain the positive electrode lithium supplementing additive.
6. The method according to claim 5, wherein the iron source in step 1) comprises one or more of iron oxide, hydroxide, sulfate, chlorate and nitrate; the lithium source comprises one or more of lithium oxide, hydroxide, peroxide, inorganic salt and organic salt.
7. The process according to claim 5, wherein the spray-drying in step 1) is carried out at a temperature of 180 to 200℃and a feed flow rate of 20 to 25mL/min.
8. The process according to claim 5, wherein the degree of vacuum in the calcination in the vacuum atmosphere in step 2) is 1X 10 -5 Pa; the temperature during calcination is 700-950 ℃ and the time is 1-5 h.
9. The method of claim 5, wherein the molecular sieve in step 3) is a type 5A molecular sieve; the grain diameter of the molecular sieve is more than or equal to 0.5mm.
10. The method according to claim 5, wherein the mixing in step 3) is solid phase mixing or liquid phase mixing; the solid phase mixing comprises one or more of grinding mixing, ball milling mixing and wall breaking machine mixing; the solvent used for liquid phase mixing comprises one or more of dichloromethane, chloroform, dimethylformamide, ethanol, acetone, tetrahydrofuran and N-methylpyrrolidone.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310349895.9A CN116314820A (en) | 2023-03-30 | 2023-03-30 | Positive electrode lithium supplementing additive and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310349895.9A CN116314820A (en) | 2023-03-30 | 2023-03-30 | Positive electrode lithium supplementing additive and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116314820A true CN116314820A (en) | 2023-06-23 |
Family
ID=86820248
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310349895.9A Pending CN116314820A (en) | 2023-03-30 | 2023-03-30 | Positive electrode lithium supplementing additive and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116314820A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117239104A (en) * | 2023-11-13 | 2023-12-15 | 宁德时代新能源科技股份有限公司 | Lithium supplementing additive, positive pole piece, battery and electricity utilization device |
| CN117638081A (en) * | 2024-01-23 | 2024-03-01 | 上海瑞浦青创新能源有限公司 | Composite lithium supplementing agent, preparation method thereof, positive electrode plate and lithium ion battery |
-
2023
- 2023-03-30 CN CN202310349895.9A patent/CN116314820A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117239104A (en) * | 2023-11-13 | 2023-12-15 | 宁德时代新能源科技股份有限公司 | Lithium supplementing additive, positive pole piece, battery and electricity utilization device |
| CN117239104B (en) * | 2023-11-13 | 2024-03-29 | 宁德时代新能源科技股份有限公司 | Lithium supplementing additive, positive pole piece, battery and electricity utilization device |
| CN117638081A (en) * | 2024-01-23 | 2024-03-01 | 上海瑞浦青创新能源有限公司 | Composite lithium supplementing agent, preparation method thereof, positive electrode plate and lithium ion battery |
| CN117638081B (en) * | 2024-01-23 | 2024-04-26 | 上海瑞浦青创新能源有限公司 | Composite lithium supplementing agent, preparation method thereof, positive electrode plate and lithium ion battery |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108878799B (en) | Mesoporous lithium aluminum silicate coated doped single crystal ternary positive electrode material and preparation method thereof | |
| CN116314820A (en) | Positive electrode lithium supplementing additive and preparation method thereof | |
| CN111063870A (en) | Nano material and preparation method thereof, electrode and secondary battery | |
| KR20220150938A (en) | Composite cathode material for lithium ion battery, manufacturing method and use thereof | |
| CN113937286B (en) | Coated modified sodium ion battery positive electrode material, preparation method thereof and battery | |
| CN112467122B (en) | Lithium orthosilicate composite material and preparation method and application thereof | |
| CN110518221B (en) | Method for preparing lithium silicate coated lithium nickel cobalt manganese oxide positive electrode material by anti-solvent method | |
| CN111211362B (en) | Lithium-supplementing washing liquid and application thereof, high-nickel multi-element positive electrode material and preparation method thereof | |
| CN114497694A (en) | Lithium supplement agent for manufacturing lithium ion battery and preparation method thereof | |
| CN116730317A (en) | Preparation method of lithium iron phosphate | |
| CN116111072A (en) | Positive electrode sodium supplement additive and preparation method and application thereof | |
| CN116706048A (en) | Nickel-cobalt-manganese ternary positive electrode material, preparation method thereof and lithium ion battery | |
| CN115642257A (en) | Lithium supplement agent, preparation method thereof, positive electrode material and lithium ion battery | |
| KR20140066414A (en) | The preparing method of lithium iron phosphate cathode active materials, the lithium iron phosphate cathod acive materials thereby and the secondary battery using the same | |
| CN114497475A (en) | Zinc-containing nitrogen-doped porous carbon-coated zinc-based negative electrode material for lithium ion battery | |
| CN113582254A (en) | Layered positive electrode material and preparation method and application thereof | |
| CN115275207B (en) | Biomass carbon-coated sodium iron phosphate composite material and preparation method and application thereof | |
| CN116470053A (en) | Composite lithium supplementing additive and preparation method and application thereof | |
| CN115939362A (en) | Positive electrode material, preparation method thereof, positive electrode piece and secondary battery | |
| CN102263248B (en) | Method for preparing carbon coated nanometer LiFePO4 | |
| CN115642232A (en) | Preparation method of carbon-coated lithium-rich lithium ferrite, product obtained by preparation method and application of product | |
| CN114956193A (en) | Preparation method and application of positive active material | |
| CN114530591A (en) | Lithium ion battery cathode material, preparation method thereof and lithium ion battery | |
| CN113764671A (en) | Anode material of lithium ion battery | |
| CN110707285A (en) | SnO (stannic oxide)2Negative electrode material lithium battery and positive plate 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 |