CN116314815A - Positive electrode lithium supplementing flame retardant additive and preparation method and application thereof - Google Patents

Positive electrode lithium supplementing flame retardant additive and preparation method and application thereof Download PDF

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CN116314815A
CN116314815A CN202310328017.9A CN202310328017A CN116314815A CN 116314815 A CN116314815 A CN 116314815A CN 202310328017 A CN202310328017 A CN 202310328017A CN 116314815 A CN116314815 A CN 116314815A
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lithium
flame retardant
supplementing
positive electrode
retardant additive
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郑奇
谢芳
王卫江
尹雪晗
张帅帅
杨雪
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Shandong Haike Innovation Research Institute Co Ltd
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Shandong Haike Innovation Research Institute Co Ltd
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/62Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • AHUMAN NECESSITIES
    • A62LIFE-SAVING; FIRE-FIGHTING
    • A62CFIRE-FIGHTING
    • A62C3/00Fire prevention, containment or extinguishing specially adapted for particular objects or places
    • A62C3/16Fire prevention, containment or extinguishing specially adapted for particular objects or places in electrical installations, e.g. cableways
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/052Li-accumulators
    • H01M10/0525Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/42Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M2004/026Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028Positive electrodes
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

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Abstract

The invention provides a positive electrode lithium supplementing flame retardant additive, and a preparation method and application thereof, and belongs to the technical field of lithium batteries. The positive electrode lithium supplementing flame retardant additive is prepared by mixing a lithium supplementing material with a flame retardant solution, and sequentially reacting and drying the obtained mixed material in an inert atmosphere; the flame retardant is phosphite, phosphate, fluorocarbonate, fluoroether, silane or phosphazene; the lithium supplementing material is represented by Li x M y N 1‑y O z Wherein, M and N are any two elements of Fe, co, ni, mn, cu, V, mo, ti, al and Si, x=2-6, y=0.5-1, and z=2-4. The positive electrode lithium supplementing flame retardant additive provided by the invention can supplement lithium at the same timeThe flame retardant effect is achieved, and the addition amount of the existing flame retardant in the electrolyte is reduced, so that the low-temperature performance and the lithium ion transmission rate of the electrolyte are not affected.

Description

Positive electrode lithium supplementing flame retardant additive and preparation method and application thereof
Technical Field
The invention belongs to the technical field of lithium battery additives, and particularly relates to a positive electrode lithium supplementing flame retardant additive, and a preparation method and application thereof.
Background
With the continuous development of new energy industry, lithium ion batteries are widely concerned, and the improvement of energy density is the key point of future development. In the battery cycle process, lithium ions in the positive electrode material can move to the negative electrode, an SEI film is generated on the surface of the negative electrode, and the SEI film consumes 7-10% of active lithium, which means Li extracted from the positive electrode material + Part of the lithium is irreversibly consumed, and lithium loss causes a decrease in battery capacity, a decrease in coulombic efficiency, and a deterioration in cycle performance. In order to further increase the energy density of lithium ion batteries, the supplementation of active lithium is an effective means to solve this problem. The current positive electrode lithium supplementing agent is mainly applied to power batteries.
In the power battery, the lithium iron phosphate and the ternary material are used as main materials, and the coulombic efficiency and the circulation process can be improved after the positive electrode lithium supplementing agent is added, but the power battery also needs to improve the multiplying power performance, and the thermal runaway of the battery can be possibly caused when the multiplying power performance is improved. In the high-rate charging process, lithium ions are rapidly released from the positive electrode to move towards the negative electrode, so that more active lithium is instantaneously present on the surface of the negative electrode, and at the moment, SEI film decomposition is easy to occur to cause lithium dendrite, so that more high-active oxygen is released from the surface of the positive electrode material, and thermal runaway of the battery is caused.
The current method for solving the thermal runaway of the battery is to add a flame retardant additive into the electrolyte, but the consumption of the flame retardant additive in the electrolyte is large (at least 5%), so that the cost and viscosity of the electrolyte are increased, and the conductivity and lithium ion transmission rate of the electrolyte are reduced, thereby influencing the cycle performance and the low-temperature performance of the battery.
Disclosure of Invention
The invention provides a positive electrode lithium supplementing flame retardant additive, a preparation method and application thereof.
In order to achieve the aim, the invention provides a positive electrode lithium supplementing flame retardant additive, which is prepared by mixing a lithium supplementing material with a flame retardant solution, and sequentially reacting and drying the obtained mixed material in an inert atmosphere; the flame retardant is phosphite, phosphate, fluorocarbonate, fluoroether, silane or phosphazene; the lithium supplementing material is represented by Li x M y N 1-y O z Wherein, M and N are any two elements of Fe, co, ni, mn, cu, V, mo, ti, al and Si, x=2-6, y=0.5-1, and z=2-4.
Preferably, the positive electrode lithium supplementing flame retardant additive takes a lithium supplementing material as a core and takes a flame retardant as a coating layer; the content of the inner core is 95 to 99.9 percent and the content of the coating layer is 0.1 to 5 percent according to the mass percent.
Preferably, the method comprises the steps of, the flame retardant is trimethyl phosphite, tris (2, 2-trifluoroethyl) phosphite, tris (hexafluoroisopropyl) phosphate, trimethyl phosphate, toluene diphenyl phosphate, triphenyl phosphate, tris (2, 2-trifluoroethyl) phosphate, dimethyl phenyl phosphate, triethyl phosphate, bis (2, 2-trifluoroethyl) carbonate, and methyl trifluoroethyl carbonate, bis hexafluoroisopropyl carbonate, 4-trifluoromethyl ethylene carbonate, 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane or ethoxypentafluoroethyl cyclotriphosphazene.
Preferably, M is Fe or Ni, and N is Al or Si.
The invention provides a preparation method of the positive electrode lithium supplementing flame retardant additive, which is characterized by comprising the following steps:
1) Mixing a lithium source, an M source and an N source to obtain precursor powder;
2) Calcining the precursor powder in a vacuum environment to obtain a lithium supplementing material;
3) Mixing the lithium supplementing material with a flame retardant solution, reacting the obtained mixture in an inert atmosphere, drying the obtained reactant, and uniformly coating the flame retardant on the surface of the lithium supplementing material to obtain the positive electrode lithium supplementing flame retardant additive.
Preferably, the lithium source in the step 1) is one or more of lithium oxide, hydroxide, peroxide, inorganic salt or organic salt; the M source is one or more of oxide, hydroxide, sulfate, chlorate and nitrate of M; the N source is one or more of N oxides, hydroxides, sulfates, chlorates, nitrates and phosphates.
Preferably, the calcination temperature in the step 2) is 700-1000 ℃, the time is 1-10 h, and the vacuum degree is more than or equal to 1 x 10 -5 Pa。
Preferably, the reaction in step 3) is carried out in an inert atmosphere for a period of time ranging from 0.5 to 3 hours.
Preferably, the drying in step 3) is freeze drying; the temperature during freeze drying is-50 to-10 ℃.
The invention provides application of the positive electrode lithium-supplementing flame-retardant additive in positive electrode lithium, wherein the addition amount of the positive electrode lithium-supplementing flame-retardant additive is 0.1-5 wt% of the positive electrode active material.
Compared with the prior art, the invention has the advantages and positive effects that:
the positive electrode lithium supplementing flame retardant additive provided by the invention mixes the lithium supplementing material with the flame retardant solution and then dries the mixture, so that the flame retardant forms a compact coating layer on the surface of the lithium supplementing agent to form a core-shell structure taking the lithium supplementing material as a core and the flame retardant as a shell, and the core lithium supplementing material can provide extra lithium ions to compensate for the SEI film and lithium ions consumed in the circulating process; the shell flame retardant can capture high-activity oxygen released by the positive electrode material before the thermal runaway of the battery, so that the thermal runaway of the battery is prevented; and can capture oxygen radical generated by the lithium supplementing agent during formation.
Furthermore, the preparation method provided by the invention adopts a vacuum sintering mode to prepare the lithium supplementing material, the sintering time is short, the obtained lithium supplementing material is loose and does not agglomerate, the particle size of the material is small, additional crushing is not needed, and the byproducts are few. The use of freeze drying can avoid deactivation of the flame retardant additive by high temperature drying. Meanwhile, the method provided by the invention is simple in process and suitable for industrial production.
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 flame retardant additive, which is prepared by mixing a lithium supplementing material and a flame retardant solution, and sequentially reacting and drying the obtained mixed material in an inert atmosphere; the flame retardant is phosphite, phosphate, fluorocarbonate, fluoroether, silane or phosphazene; the lithium supplementing material is represented by Li x M y N 1- y O z Wherein, M and N are any two elements of Fe, co, ni, mn, cu, V, mo, ti, al and Si, x=2-6, y=0.5-1, and z=2-4.
In the invention, the positive electrode lithium supplementing flame retardant additive takes a lithium supplementing material as a core and takes a flame retardant as a coating layer. The content of the inner core is preferably 95-99.9% by mass, and the content of the coating layer is preferably 0.1-5% by mass. In the invention, the dosage of the coating layer is controlled to be 0.1-5%, so that the flame retardant effect can be ensured and the capacity of the lithium supplementing material is not influenced.
In the present invention, the flame retardant is preferably trimethyl phosphite, tris (2, 2-trifluoroethyl) phosphite, tris (hexafluoroisopropyl) phosphate, trimethyl phosphate, toluene diphenyl phosphate, triphenyl phosphate, tris (2, 2-trifluoroethyl) phosphate, dimethyl phenyl phosphate, triethyl phosphate, or a mixture thereof bis (2, 2-trifluoroethyl) carbonate, methyltrifluoroethyl carbonate, bishexafluoroisopropyl carbonate, 4-trifluoromethyl ethylene carbonate, 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane or ethoxypentafluoroethylcyclotriphosphazene, more preferred are ethoxypentafluoroethylcyclotriphosphazene, trimethyl phosphite, trimethyl phosphate, and vinyltriethoxysilane.
In the present invention, M is preferably Fe or Ni, and N is preferably Al or Si.
The positive electrode lithium supplementing flame retardant provided by the invention is characterized in that the surface of the lithium supplementing agent is coated with the flame retardant, and the core lithium supplementing agent can provide extra lithium ions to compensate the SEI film and lithium ions consumed in the circulating process; the coating layer outer shell flame retardant can capture high-activity oxygen released by the positive electrode material before the thermal runaway of the battery, so that the thermal runaway of the battery is prevented; meanwhile, oxygen radical free radicals generated by the lithium supplementing agent during formation can be captured, so that formation gas is reduced, high-temperature storage gas production is reduced, and the electrochemical performance and the safety performance of the battery are improved. The lithium is supplemented, and meanwhile, the flame retardant effect is achieved, so that the problems that lithium dendrites possibly caused by the increase of the lithium content at the negative electrode end in the circulation process of the lithium ion battery using the positive electrode lithium supplementing agent at present are solved, SEI films are decomposed due to the lithium dendrites, and thermal runaway caused by high active oxygen is generated in the positive electrode material are solved; meanwhile, the fire retardant is used as a coating layer, so that water and CO in the air can be isolated 2 The air stability of the material is improved, and the increase of the base number in the processes of material storage, transportation, tabletting and the like is inhibited. The flame retardant is added into the positive electrode lithium supplementing material, so that the flame retardant additive is not added into the electrolyte, the safety of the battery is ensured, and the low-temperature performance and the lithium ion transmission rate of the electrolyte are not influenced.
The invention provides a preparation method of the positive electrode lithium supplementing flame retardant additive, which is characterized by comprising the following steps:
1) Mixing a lithium source, an M source and an N source to obtain precursor powder;
2) Calcining the precursor powder in a vacuum environment to obtain a lithium supplementing material;
3) Mixing the lithium supplementing material with a flame retardant solution, reacting the obtained mixture in an inert atmosphere, drying the obtained reactant, and uniformly coating the flame retardant on the surface of the lithium supplementing material to obtain the positive electrode lithium supplementing flame retardant additive.
The invention mixes lithium source, M source and N source to obtain precursor powder. In the present invention, the mixing is preferably performed by grinding or dissolving the lithium source, the M source, and the N source in a solvent and then spray-drying. In the present invention, the solvent is preferably deionized water, ethanol or a mixed solution of water and ethanol. In the present invention, the spray-drying temperature is preferably 150 to 250 ℃.
In the present invention, the lithium source is preferably one or more of lithium oxide, hydroxide, peroxide, inorganic salt or organic salt; more preferably Li 2 O、LiOH、Li 2 CO 3 、LiNO 3 、Li 2 C 2 O 4 、CH 3 One or more of COOLi; most preferably LiOH, li 2 CO 3 Or LiNO 3 . In the invention, the M source is preferably one or more of oxide, hydroxide, sulfate, chlorate and nitrate of M; more preferably Fe 2 O 3 、Fe 3 O 4 、FeC 2 O 4 、Fe(NO 3 ) 3 ·9H 2 O、FeCl 3 、Fe 2 (SO 4 ) 3 、NiO、Ni(NO 3 ) 2 、Ni 2 SO 4 Or NiCl 3 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 or Ni (NO) 3 ) 2 . In the invention, the N source is preferably one or more of oxides, hydroxides, sulfates, chlorates, nitrates and phosphates of N; more preferably Al 2 O 3 、AlCl 3 、Al 2 (SO 4 ) 3 、KAl(SO 4 ) 2 ·12H 2 O、CuCl 2 、CuSO 4 ·5H 2 O、Cu(NO 3 ) 2 、MnO 2 SiOx, silicate or silicone; most preferably Al 2 (SO 4 ) 3 、CuSO 4 ·5H 2 O、MnO 2 Or a silicone.
After the precursor powder is obtained, the precursor powder is calcined in a vacuum environment to obtain the lithium supplementing material. In the invention, calcination is carried out under vacuum condition, so that the generated by-product gas can be rapidly discharged from the interior of the material, thereby obtaining loose and uncracked materialLithium supplementing material of the block. And 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 time is shortened. In the invention, the temperature of the vacuum calcination is 700-1000 ℃, the time is 1-10 h, and the vacuum degree is more than or equal to 1 x 10 -5 Pa。
After the lithium supplementing material is obtained, the lithium supplementing material is mixed with the flame retardant solution, the obtained mixed material reacts in inert atmosphere, the obtained reactant is dried, and the flame retardant is uniformly coated on the surface of the lithium supplementing material, so that the anode lithium supplementing flame retardant additive is obtained. In the present invention, the reaction is preferably carried out in an inert atmosphere for a period of time of 0.5 to 3 hours. In the present invention, the inert atmosphere is preferably nitrogen. In the present invention, the drying is preferably freeze-drying; the temperature during freeze drying is-50 to-10 ℃. In the present invention, freeze drying can avoid deactivation of the flame retardant additive by high temperature drying.
The invention provides application of the positive electrode lithium supplementing flame retardant additive in the positive electrode lithium supplementing of a lithium ion battery, wherein the addition amount of the positive electrode lithium supplementing flame retardant additive is 0.1-5 wt% of the positive electrode active material. In the present invention, the positive electrode active material is preferably LiCoO 2 、LiFePO 4 And at least one of NCM, more preferably NCM811. In the present invention, the lithium ion battery preferably further includes a current collector, a negative electrode, a separator, and an electrolyte. The negative electrode active material is preferably at least one of natural graphite, artificial graphite, soft carbon, hard carbon, lithium titanate, silicon carbon, and silicon oxygen; more preferably a silicon oxygen negative electrode.
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
According to formula Li 5 FeO 4 Weighing LiNO according to the corresponding element mole ratio 3 、Fe(NO 3 ) 3 ·9H 2 O. Fe (NO) 3 ) 3 ·9H 2 The O solution is gradually dripped into boiling deionized water, and is stirred during dripping,and after the dripping is finished, reacting for 3 hours at 90 ℃ to obtain ferric hydroxide colloid. Drop-adding LiNO into ferric hydroxide colloid 3 And (3) obtaining a precursor solution after the solution, and carrying out spray drying (the temperature is 150 ℃) on the precursor solution to obtain precursor powder.
Heating the precursor powder to 950 ℃ at a speed of 15 ℃/min under vacuum condition, preserving heat for 1 hour, and cooling to room temperature at a speed of 15 ℃/min to obtain Li 5 FeO 4 . Li is mixed with 5 FeO 4 Adding the mixture and trimethyl phosphate into a reaction kettle containing inert atmosphere according to the mass ratio of 98:2, mixing for 0.5h, and freeze-drying the reaction product at-50 ℃ for 1h after the reaction is finished to obtain the anode lithium-supplementing flame-retardant additive.
Example 2
The positive electrode lithium-supplementing agent was Li as in example 1 5 FeO 4 . Li is mixed with 5 FeO 4 Adding the mixture and ethoxy pentafluoro cyclotriphosphazene into a reaction kettle containing inert atmosphere according to the mass ratio of 99:1 for reaction for 1h, and freeze-drying the reaction product at-30 ℃ for 2h after the reaction is finished to obtain the anode lithium supplementing flame retardant additive.
Example 3
According to formula Li 2 NiO 2 And weighing LiOH and NiO according to the corresponding molar ratio of each element, placing the weighed samples into a ball milling tank, and ball milling at 500rpm for 5 hours to obtain precursor powder.
Heating the obtained precursor powder to 800 ℃ at a speed of 20 ℃/min under vacuum condition, preserving heat for 8 hours, and cooling to room temperature at a speed of 20 ℃/min to obtain Li 2 NiO 2 . Li is mixed with 2 NiO 2 Adding the mixture and vinyl triethoxysilane into a reaction kettle containing inert atmosphere according to the mass ratio of 95:5 for reaction for 3 hours, and freeze-drying the reaction product at-20 ℃ for 5 hours after the reaction is finished to obtain the anode lithium supplementing flame retardant additive.
Example 4
According to formula Li 4 SiO 4 Weighing LiOH H according to the corresponding molar ratio of each element 2 O、SiO 2 And placing the weighed sample into a ball milling tank, and ball milling at 500rpm for 5 hours to obtain precursor powder.
Subjecting the precursor powder to vacuum conditions to obtainHeating to 900 ℃ at a speed of 15 ℃/min, preserving heat for 6 hours, and cooling to room temperature at a speed of 15 ℃/min to obtain Li 4 SiO 4 Li is taken as 4 SiO 4 Adding the mixture and trimethyl phosphite into a reaction kettle containing inert atmosphere according to the mass ratio of 97:3 for reaction for 3 hours, and freeze-drying the reaction product at-40 ℃ for 1.5 hours after the reaction is finished to obtain the anode lithium-supplementing flame-retardant additive.
Example 5
According to formula Li 5 Fe 0.95 Al 0.05 O 4 Weighing LiNO according to the corresponding element mole ratio 3 、Fe(NO 3 ) 3 ·9H 2 O、Al(NO 3 ) 3 . Fe (NO) 3 ) 3 ·9H 2 And gradually dropwise adding the O solution into boiling deionized water, stirring in the dropwise adding process, and reacting at 90 ℃ for 3 hours after the dropwise adding is finished to obtain ferric hydroxide colloid. Dropwise adding Al (NO) into ferric hydroxide colloid 3 ) 3 And LiNO 3 And (3) obtaining a precursor solution after the solution, and carrying out spray drying (the temperature is 150 ℃) on the precursor solution to obtain precursor powder.
Heating the precursor powder to 950 ℃ at a speed of 15 ℃/min under vacuum condition, preserving heat for 1 hour, and cooling to room temperature at a speed of 15 ℃/min to obtain Li 5 Fe 0.95 Al 0.05 O 4 . Li is mixed with 5 Fe 0.95 Al 0.05 O 4 Adding the mixture and trimethyl phosphate into a reaction kettle containing inert atmosphere according to the mass ratio of 98:2, mixing for 0.5h, and freeze-drying the reaction product at-50 ℃ for 1h after the reaction is finished to obtain the anode lithium-supplementing flame-retardant additive.
Example 6
According to formula Li 2 Ni 0.98 Si 0.02 O 2 And weighing LiOH, niO, siO corresponding to the molar ratio of each element, placing the weighed sample into a ball milling tank, and ball milling at 500rpm for 5 hours to obtain precursor powder.
Heating the obtained precursor powder to 800 ℃ at a speed of 20 ℃/min under vacuum condition, preserving heat for 8 hours, and cooling to room temperature at a speed of 20 ℃/min to obtain Li 2 Ni 0.98 Si 0.02 O 2 . Li is mixed with 2 Ni 0.98 Si 0.02 O 2 Adding the mixture and vinyl triethoxysilane into a reaction kettle containing inert atmosphere according to the mass ratio of 95:5 for reaction for 3 hours, and freeze-drying the reaction product at-20 ℃ for 5 hours after the reaction is finished to obtain the anode lithium supplementing flame retardant additive.
Comparative example 1
The difference from example 1 is that the lithium-compensating material is obtained by sintering a precursor under nitrogen atmosphere, and the other operation modes are exactly the same as in example 1.
Comparative example 2
The difference from example 1 is that the lithium supplement material prepared is not coated with a flame retardant additive.
Comparative example 3
The difference from example 1 is that the drying mode in the preparation of the lithium-compensating flame retardant is spray drying, the spray drying temperature being 200 ℃.
Performance testing
The products of the above examples and comparative examples were added to a pouch cell for electrochemical performance testing, gas production and needling experiments, wherein the positive electrode was commercial NCM811, the negative electrode was commercial silicon carbon negative electrode composite graphite, and the electrolyte was 1mol/L LiPF 6 And EC: EMC with a mass ratio of 7:3, the battery capacity was 2.0Ah, the formation cutoff voltage was 4.4V, the circulating voltage range was 2.8V to 4.2V, the formation gas yield was tested respectively, the capacity retention rate and the gas expansion rate after 100 cycles of 1C, and the test results are shown in Table 1.
Table 1 test results
Figure BDA0004153899140000081
Note that: the gas yield test method of the formation in the table is that the gas volume of the gas bag chamber after the formation of the soft package battery is tested by a drainage method, and the gas expansion rate test method is that the thickness change of the highest point before and after the circulation of the soft package battery is measured.
As can be seen from Table 1, the positive electrode lithium supplement agent coated with the flame retardant exerts better safety performance while the lithium supplement amount is not influenced, and the calcination is performed in a vacuum mode, so that the battery cycle performance is improved compared with that of calcination under inert gas, because the particle size of the lithium supplement agent prepared by the method is smaller, the residual alkali amount is low, the lithium supplement agent can be mixed with the positive electrode material uniformly, lithium ions can be fully extracted, and the capacity is exerted.
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 flame retardant additive is characterized by being prepared by mixing a lithium supplementing material with a flame retardant solution, and sequentially reacting and drying the obtained mixed material in an inert atmosphere; the flame retardant is phosphite, phosphate, fluorocarbonate, fluoroether, silane or phosphazene; the lithium supplementing material is represented by Li x M y N 1-y O z Wherein, M and N are any two elements of Fe, co, ni, mn, cu, V, mo, ti, al and Si, x=2-6, y=0.5-1, and z=2-4.
2. The positive electrode lithium-supplementing flame-retardant additive according to claim 1, wherein the positive electrode lithium-supplementing flame-retardant additive takes a lithium-supplementing material as a core and takes a flame retardant as a coating layer; the content of the inner core is 95 to 99.9 percent and the content of the coating layer is 0.1 to 5 percent according to the mass percent.
3. The positive electrode lithium-supplementing flame-retardant additive according to claim 1, wherein, the flame retardant is trimethyl phosphite, tris (2, 2-trifluoroethyl) phosphite, tris (hexafluoroisopropyl) phosphate, trimethyl phosphate, toluene diphenyl phosphate, triphenyl phosphate, tris (2, 2-trifluoroethyl) phosphate, dimethyl phenyl phosphate, triethyl phosphate, bis (2, 2-trifluoroethyl) carbonate, and methyl trifluoroethyl carbonate, bis hexafluoroisopropyl carbonate, 4-trifluoromethyl ethylene carbonate, 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane or ethoxypentafluoroethyl cyclotriphosphazene.
4. The positive electrode lithium-compensating flame retardant additive of claim 1, wherein M is Fe or Ni and N is Al or Si.
5. The method for preparing the positive electrode lithium-supplementing flame-retardant additive according to any one of claims 1 to 4, which is characterized by comprising the following steps:
1) Mixing a lithium source, an M source and an N source to obtain precursor powder;
2) Calcining the precursor powder in a vacuum environment to obtain a lithium supplementing material;
3) Mixing the lithium supplementing material with a flame retardant solution, reacting the obtained mixture in an inert atmosphere, drying the obtained reactant, and uniformly coating the flame retardant on the surface of the lithium supplementing material to obtain the positive electrode lithium supplementing flame retardant additive.
6. The preparation method according to claim 5, wherein the lithium source in step 1) is one or more of lithium oxide, hydroxide, peroxide, inorganic salt or organic salt; the M source is one or more of oxide, hydroxide, sulfate, chlorate and nitrate of M; the N source is one or more of N oxides, hydroxides, sulfates, chlorates, nitrates and phosphates.
7. The preparation method according to claim 5, wherein the calcination temperature in step 2) is 700-1000 ℃ for 1-10 hours, and the vacuum degree is not less than 1 x 10 -5 Pa。
8. The process according to claim 5, wherein the reaction is carried out in an inert atmosphere in step 3) for a period of 0.5 to 3 hours.
9. The method of claim 5, wherein the drying in step 3) is freeze drying; the temperature during freeze drying is-50 to-10 ℃.
10. The use of the positive electrode lithium-supplementing flame retardant additive according to any one of claims 1 to 4 in positive electrode lithium supplementing, wherein the addition amount of the positive electrode lithium-supplementing flame retardant additive is 0.1 to 5wt% of the positive electrode active material.
CN202310328017.9A 2023-03-30 2023-03-30 Positive electrode lithium supplementing flame retardant additive and preparation method and application thereof Pending CN116314815A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117059804A (en) * 2023-10-13 2023-11-14 瑞浦兰钧能源股份有限公司 Chemical pre-lithium agent, lithium ion battery and preparation method of lithium ion battery
CN117457910A (en) * 2023-12-22 2024-01-26 天鹏锂能技术(淮安)有限公司 Positive pole piece and sodium ion battery

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117059804A (en) * 2023-10-13 2023-11-14 瑞浦兰钧能源股份有限公司 Chemical pre-lithium agent, lithium ion battery and preparation method of lithium ion battery
CN117059804B (en) * 2023-10-13 2024-03-19 瑞浦兰钧能源股份有限公司 Chemical pre-lithium agent, lithium ion battery and preparation method of lithium ion battery
CN117457910A (en) * 2023-12-22 2024-01-26 天鹏锂能技术(淮安)有限公司 Positive pole piece and sodium ion battery
CN117457910B (en) * 2023-12-22 2024-04-02 天鹏锂能技术(淮安)有限公司 Positive pole piece and sodium ion battery

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