CN115663286B - Lithium ion battery - Google Patents

Lithium ion battery Download PDF

Info

Publication number
CN115663286B
CN115663286B CN202211570289.1A CN202211570289A CN115663286B CN 115663286 B CN115663286 B CN 115663286B CN 202211570289 A CN202211570289 A CN 202211570289A CN 115663286 B CN115663286 B CN 115663286B
Authority
CN
China
Prior art keywords
equal
positive electrode
lithium ion
less
ion battery
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.)
Active
Application number
CN202211570289.1A
Other languages
Chinese (zh)
Other versions
CN115663286A (en
Inventor
钱韫娴
胡时光
李红梅
向晓霞
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shenzhen Capchem Technology Co Ltd
Original Assignee
Shenzhen Capchem Technology Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Shenzhen Capchem Technology Co Ltd filed Critical Shenzhen Capchem Technology Co Ltd
Priority to CN202211570289.1A priority Critical patent/CN115663286B/en
Publication of CN115663286A publication Critical patent/CN115663286A/en
Application granted granted Critical
Publication of CN115663286B publication Critical patent/CN115663286B/en
Priority to PCT/CN2023/127475 priority patent/WO2024120053A1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • 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)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Secondary Cells (AREA)

Abstract

In order to overcome the problem of insufficient cycle performance caused by unstable passivation film of the existing lithium ion battery, the invention provides a lithium ion battery, which comprises a positive electrode, a negative electrode, a nonaqueous electrolyte and a diaphragm arranged between the positive electrode and the negative electrode, wherein the positive electrode comprises a positive electrode material layer containing a positive electrode active material, the surface of the positive electrode material layer contains a first amphoteric oxide, the surface of the diaphragm contains a second amphoteric oxide, and the nonaqueous electrolyte comprises a nonaqueous organic solvent and PO 2 F 2 ‑ And a lithium salt comprising lithium hexafluorophosphate; the lithium ion battery meets the following conditions: m is more than or equal to 0.1 and less than or equal to (10, b+c)/a is more than or equal to 30, a is more than or equal to 0.5 and less than or equal to 1.5,0.01, m is more than or equal to 0.8,0.01 and less than or equal to b is more than or equal to 2, and c is more than or equal to 0.5 and less than or equal to 30. The lithium ion battery provided by the invention has good cycling stability, and the cycle life of the battery is effectively prolonged.

Description

Lithium ion battery
Technical Field
The invention belongs to the technical field of energy storage devices, and particularly relates to a lithium ion battery.
Background
The lithium ion battery is widely applied to electric automobiles and consumer products due to the advantages of high voltage platform, less self-discharge, high output power, no memory effect, long cycle life, less environmental pollution and the like. With the expansion of application range, especially with the popularization of smart phones and electric vehicles, the demands for cycle life of lithium ion batteries are increasing.
In the use process of the lithium ion battery, the positive electrode active material with strong oxidation activity can easily oxidize the electrolyte, so that the electrolyte is decomposed to produce gas. In the prior art, lithium difluorophosphate is usually added into the electrolyte, so that a passivation film can be formed on the surface of the positive electrode, and the oxidation activity of the positive electrode active material is reduced, thereby improving the cycle life of the battery. The additives generally have a higher level of occupied molecular orbitals (HOMO) than the electrolyte solvent and the lithium salt. Therefore, it is oxidized before the main electrolyte component during charging and then forms a decomposition layer on the surface of the positive electrode to prevent further decomposition of the electrolyte, and the passivation film formed on the surface of the positive electrode is not stable enough to cause the lithium ion battery to be used in the cycle and storage processes (especially in the cycle and storage processes)End of storage) is subjected to continuous oxidative decomposition, and the direct current internal resistance in the cycle and storage process of the lithium ion battery is continuously increased, so that the use of the lithium ion battery is seriously influenced. More importantly, the introduction of conventional additives into the electrolyte can lead to additional risks of increasing the moisture in the electrolyte, water and LiPF 6 HF is produced by the reaction of (a) and is detrimental to the cyclic stability of the layered cathode active material, especially at high voltages.
Disclosure of Invention
Aiming at the problem of insufficient cycle performance caused by unstable passivation film in the existing lithium ion battery, the invention provides a lithium ion battery.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the invention provides a lithium ion battery, which comprises a positive electrode, a negative electrode, a nonaqueous electrolyte and a diaphragm arranged between the positive electrode and the negative electrode, wherein the positive electrode comprises a positive electrode material layer containing a positive electrode active material, the surface of the positive electrode material layer contains a first amphoteric oxide, the surface of the diaphragm contains a second amphoteric oxide, and the nonaqueous electrolyte comprises a nonaqueous organic solvent and PO 2 F 2 - And a lithium salt comprising lithium hexafluorophosphate;
the lithium ion battery meets the following conditions:
m is more than or equal to 0.1 and less than or equal to (10, b+c)/a is more than or equal to 30, a is more than or equal to 0.5 and less than or equal to 1.5,0.01, m is more than or equal to 0.8,0.01 and less than or equal to b is more than or equal to 2, and c is more than or equal to 0.5 and less than or equal to 30;
wherein a is the molar concentration of lithium hexafluorophosphate in the nonaqueous electrolyte, and the unit is mol/L;
m is PO in the nonaqueous electrolyte 2 F 2 - The mass percentage of (2) is as follows;
b is the percentage content of the first amphoteric oxide in the mass of the positive electrode material layer, and the unit is;
and c is the percentage content of the second amphoteric oxide in the mass of the diaphragm, and the unit is percent.
Optionally, the lithium ion battery meets the following conditions:
0.5≤m*(10*b+c)/a≤10。
optionally, the molar concentration a of the lithium hexafluorophosphate in the nonaqueous electrolyte is 0.7-1.2 mol/L.
Optionally, PO in the non-aqueous electrolyte 2 F 2 - The mass percentage content m is 0.05% -0.5%.
Optionally, the first amphoteric oxide accounts for 0.03% -1% of the mass of the positive electrode material layer.
Optionally, the second amphoteric oxide accounts for 3% -20% of the mass of the diaphragm.
Optionally, the first amphoteric oxide and the second amphoteric oxide are each independently selected from at least one of alumina, zirconia, tungsten oxide, and titanium oxide.
Optionally, the positive electrode active material comprises LiFe 1-x’ M’ x’ PO 4 、LiMn 2-y’ M y’ O 4 And LiNi x Co y Mn z M 1-x-y- z O 2 At least one of sulfide, selenide and halide, wherein M 'is at least one of Mn, mg, co, ni, cu, zn, al, sn, B, ga, cr, sr, V or Ti, M is at least one of Fe, co, ni, mn, mg, cu, zn, al, sn, B, ga, cr, sr, V or Ti, and x' is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, x is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and x+y+z is more than or equal to 1.
Optionally, the nonaqueous electrolyte further comprises an additive, wherein the additive comprises at least one of a cyclic sulfate compound, a sultone compound, a cyclic carbonate compound, a phosphate compound, a borate compound and a nitrile compound;
The content of the additive is 0.01% -30% based on 100% of the total mass of the nonaqueous electrolyte.
Optionally, the cyclic sulfate compound is selected from the group consisting of vinyl sulfate, propylene sulfate, vinyl methyl sulfate,、、
、、At least one of (a) and (b);
the sultone compound is selected from 1, 3-propane sultone, 1, 4-butane sultone, 1, 3-propylene sultone,At least one of (a) and (b);
the cyclic carbonate compound is at least one selected from ethylene carbonate, methylene ethylene carbonate, fluoroethylene carbonate, trifluoromethyl ethylene carbonate, bifluoroethylene carbonate and a compound shown in a structural formula 1:
structure 1
In the structural formula 1, R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently selected from one of a hydrogen atom, a halogen atom, a C1-C5 group;
the phosphate compound is at least one selected from tris (trimethylsilane) phosphate, tris (trimethylsilane) phosphite or a compound shown in a structural formula 2:
structure 2
In the structural formula 2, R 31 、R 32 、R 33 Each independently selected from the group consisting of C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, -Si (C) m H 2m+1 ) 3 M is a natural number of 1 to 3, and R 31 、R 32 、R 33 At least one of them is an unsaturated hydrocarbon group;
The borate compound is at least one selected from tri (trimethylsilane) borate and tri (triethylsilane) borate;
the nitrile compound is at least one selected from succinonitrile, glutaronitrile, ethylene glycol bis (propionitrile) ether, hexanedinitrile, adiponitrile, pimelic nitrile, suberonitrile, nonyldinitrile and decyldinitrile.
According to the lithium ion battery provided by the invention, the surface of the positive electrode material layer contains the first amphoteric oxide, the surface of the diaphragm contains the second amphoteric oxide, and the positive electrode material layer can react with lithium hexafluorophosphate added in the electrolyte to generate a large amount of beneficial PO 2 F 2 - In the battery formation process, PO 2 F 2 - The inventors have found through a great deal of research that when the molar concentration a of lithium hexafluorophosphate in the nonaqueous electrolyte and PO in the nonaqueous electrolyte are 2 F 2 - When the mass percentage content m, the mass percentage content b of the first amphoteric oxide and the mass percentage content c of the second amphoteric oxide in the positive electrode material layer satisfy the conditions that m is less than or equal to 0.1 (10 x b+c)/a is less than or equal to 30, a is less than or equal to 0.5 and less than or equal to 1.5,0.01, m is less than or equal to 0.8,0.01 and less than or equal to 2, c is less than or equal to 0.5 and less than or equal to 30, the densification degree of the passivation film generated on the surface of the positive electrode material layer can be effectively controlled, so that the passivation film is in a more stable state, the rupture of the passivation film is avoided in the charge-discharge cycle of the battery, the cycle stability of the nonaqueous electrolyte and the positive electrode active material is ensured, and the cycle performance of the battery is effectively improved.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects solved by the invention more clear, the invention is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The embodiment of the invention provides a lithium ion battery, which comprises a positive electrode, a negative electrode, a nonaqueous electrolyte and a diaphragm arranged between the positive electrode and the negative electrode, wherein the positive electrode comprises a positive electrode material layer containing a positive electrode active material, the surface of the positive electrode material layer contains a first amphoteric oxide, the surface of the diaphragm contains a second amphoteric oxide, and the nonaqueous electrolyte comprises a nonaqueous organic solvent and PO 2 F 2 - And a lithium salt comprising lithium hexafluorophosphate;
the lithium ion battery meets the following conditions:
m is more than or equal to 0.1 and less than or equal to (10, b+c)/a is more than or equal to 30, a is more than or equal to 0.5 and less than or equal to 1.5,0.01, m is more than or equal to 0.8,0.01 and less than or equal to b is more than or equal to 2, and c is more than or equal to 0.5 and less than or equal to 30;
wherein a is the molar concentration of lithium hexafluorophosphate in the nonaqueous electrolyte, and the unit is mol/L;
m is PO in the nonaqueous electrolyte 2 F 2 - The mass percentage of (2) is as follows;
b is the percentage content of the first amphoteric oxide in the mass of the positive electrode material layer, and the unit is;
And c is the percentage content of the second amphoteric oxide in the mass of the diaphragm, and the unit is percent.
In the description of the present invention, the term "percentage content of the first amphoteric oxide based on the mass of the positive electrode material layer" refers to the relative mass content of the first amphoteric oxide based on 100% of the mass of the positive electrode active layer. The term "percentage content of the second amphoteric oxide based on the mass of the separator" refers to the relative mass content of the second amphoteric oxide based on 100% of the mass of the separator.
The first amphoteric oxide on the surface of the positive electrode material layer and the second amphoteric oxide on the surface of the diaphragm can react with lithium hexafluorophosphate added in the electrolyte to generate a large amount of beneficial PO 2 F 2 - 。
The reaction equation is: 2Al 2 O 3 +3PF 6 - → AlF 3 + 3 PO 2 F 2 - 。
The above amphoteric oxides of Al 2 O 3 By way of example to illustrate the inventive concept, from the above mechanism, those skilled in the art will appreciate that the inventive object of the present invention can be similarly achieved when the material of the positive electrode material layer or the separator surface is other amphoteric oxide.
If the material of the positive electrode material layer and the separator surface is a non-amphoteric oxide, such as magnesium oxide, boron oxide, silicon oxide, etc., then the separator is made of LiPF 6 Exhibit little or no reactivity, so that little or no PO is formed 2 F 2 - The condition limit of the application is not satisfied, and the improvement of the battery cycle performance is also not facilitated.
In the battery formation process, PO 2 F 2 - The inventors have found through a great deal of research that when the molar concentration a of lithium hexafluorophosphate in the nonaqueous electrolyte and PO in the nonaqueous electrolyte are 2 F 2 - When the mass percentage content m, the mass percentage content b of the first amphoteric oxide and the mass percentage content c of the second amphoteric oxide in the positive electrode material layer satisfy the conditions that m is less than or equal to 0.1 (10 x b+c)/a is less than or equal to 30, a is less than or equal to 0.5 and less than or equal to 1.5,0.01, m is less than or equal to 0.8,0.01 and less than or equal to 2, c is less than or equal to 0.5 and less than or equal to 30, the densification degree of the passivation film generated on the surface of the positive electrode material layer can be effectively controlled, so that the passivation film is in a more stable state, the rupture of the passivation film is avoided in the charge-discharge cycle of the battery, the cycle stability of the nonaqueous electrolyte and the positive electrode active material is ensured, and the cycle performance of the battery is effectively improved.
Meanwhile, the surface of the positive electrode material layer and the surface of the diaphragm both contain amphoteric oxides, so that the synergistic effect of the positive electrode material layer and the diaphragm can be fully exerted, the improvement of the cycle life of the battery is more facilitated, and when only one of the surfaces of the positive electrode material layer or the diaphragm is used Containing amphoteric oxides, although PO can also be produced 2 F 2 - But it generates PO 2 F 2 - The smaller the amount, the more improved the battery performance is not produced.
In a preferred embodiment, the lithium ion battery satisfies the following conditions:
0.5≤m*(10*b+c)/a≤10。
when the molar concentration a of lithium hexafluorophosphate in the nonaqueous electrolyte solution and PO in the nonaqueous electrolyte solution are 2 F 2 - When the mass percentage content m, the mass percentage content b of the first amphoteric oxide and the mass percentage content c of the second amphoteric oxide and the separator satisfy the above conditions, the dynamic performance and the cycle performance of the battery can be better improved on the premise of ensuring the energy density of the battery.
When the value of m (10 x b+c)/a is too low, the side reaction of the nonaqueous electrolyte on the surface of the strong-oxidizing positive electrode material layer cannot be effectively inhibited, and PO is greatly reduced 2 F 2 - The internal resistance of the battery increases, which causes insufficient high-temperature stability of the electrolyte, affects the high-temperature cycle and storage performance of the battery, and deteriorates the cycle life of the battery.
When the value of m (10 x b+c)/a is too high, the energy density and dynamic performance of the battery are reduced, the conductivity of the electrolyte is too low, and the polarization of the battery is increased, so that the normal use of the battery is affected, and the PO is also affected 2 F 2 - Is disadvantageous for the improvement of the cycle life of the battery.
In some embodiments, the molar concentration a of lithium hexafluorophosphate in the nonaqueous electrolytic solution may be 0.5mol/L, 0.6mol/L, 0.7mol/L, 0.8mol/L, 0.9mol/L, 1.0mol/L, 1.1mol/L, 1.2mol/L, 1.3mol/L, 1.4mol/L, or 1.5mol/L.
In a preferred embodiment, the molar concentration a of lithium hexafluorophosphate in the nonaqueous electrolyte is 0.7-1.2 mol/L.
When the content of lithium hexafluorophosphate in the nonaqueous electrolytic solution is too low, on the one hand, it results in an overall electrolyte salt in the nonaqueous electrolytic solutionThe content is less, the ion conductivity of the nonaqueous electrolyte is affected, and the reactivity with the amphoteric oxide on the surface of the positive electrode material layer or the diaphragm is also affected, so that the amphoteric oxide and PF are reduced 6 - The anions react to form PO 2 F 2 - Is a measure of (2); when the content of lithium hexafluorophosphate in the nonaqueous electrolyte is high, the viscosity of the nonaqueous electrolyte is increased, the conductivity is reduced, and the ionic conductivity of the nonaqueous electrolyte is not improved.
In some embodiments, the PO in the nonaqueous electrolytic solution 2 F 2 - The mass percentage m of (c) may be 0.01%, 0.02%, 0.03%, 0.05%, 0.07%, 0.08%, 0.09%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.6%, 0.7% or 0.8%.
In a preferred embodiment, PO in the nonaqueous electrolytic solution 2 F 2 - The mass percentage content m is 0.05% -0.5%.
In the present invention, PO in the nonaqueous electrolytic solution 2 F 2 - Can be combined with PF through amphoteric oxides 6 - The anions are generated by reaction and can be added into the nonaqueous electrolyte by an additional adding mode; when PO is 2 F 2 - From amphoteric oxides and PF 6 - In the case of anionic reaction, PO in the nonaqueous electrolyte 2 F 2 - The production amount of the lithium hexafluorophosphate is affected by a large amount of factors, and in addition to the content of the amphoteric oxide and the concentration of the lithium hexafluorophosphate, conditions such as the installation position of the amphoteric oxide and the contact area with the nonaqueous electrolyte, the control voltage of the first battery formation, etc., lead to PO in the nonaqueous electrolyte 2 F 2 - Too little PO due to the difference in the amount of produced 2 F 2 - The performance improvement for lithium ion batteries is not obvious, but excessive PO is generated 2 F 2 - The generation may result in a decrease in the lithium hexafluorophosphate of the main lithium salt, thereby being disadvantageous for the improvement of the ion conduction rate of the lithium ion battery.
In some embodiments, the first amphoteric oxide may be 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.2%, 0.4%, 0.5%, 0.7%, 0.9%, 1.0%, 1.1%, 1.3%, 1.5%, 1.8%, or 2.0% of the positive electrode material layer by mass b.
In a preferred embodiment, the first amphoteric oxide accounts for 0.03% -1% of the mass of the positive electrode material layer.
The first amphoteric oxide is arranged on the surface of the positive electrode material layer, can isolate the positive electrode active material with strong oxidizing property from being in direct contact with the nonaqueous electrolyte, inhibits the side reaction of the nonaqueous electrolyte on the surface of the positive electrode material layer with strong oxidizing property, reduces the gas quantity generated by the decomposition of the nonaqueous electrolyte, and further well prolongs the service life of the battery. Meanwhile, the amphoteric oxide can neutralize residual alkali on the surface of the positive electrode material layer, consume HF generated in the electrolyte or in the using process of the battery, inhibit the dissolution of transition metal in the positive electrode active material, improve the stability of the interface between the positive electrode active material and the electrolyte, ensure the acid-base balance of a battery system, and further finally improve the electrochemical performance of the battery. Too low a content b of the first amphoteric oxide in the mass of the positive electrode material layer is detrimental to the improvement of the structural stability of the positive electrode active material and the PO 2 F 2 - Too high a level is detrimental to the improvement of the energy density and the reduction of the internal resistance of the battery.
In some embodiments, the second amphoteric oxide may comprise 0.5%, 0.7%, 0.9%, 1.0%, 1.1%, 1.3%, 1.5%, 1.8%, 2.0%, 2.3%, 2.7%, 3.0%, 3.3%, 3.7%, 4.0%, 4.3%, 4.7%, 5%, 8%, 10%, 13%, 15%, 16%, 18%, 21%, 23%, 24%, 26%, 27%, 29% or 30% of the separator by mass c.
In a preferred embodiment, the second amphoteric oxide accounts for 3% -20% of the mass of the diaphragm.
The second amphoteric oxide on the surface of the diaphragm plays a key role in inhibiting or reducing the harmful crosstalk phenomenon generated by the positive electrode, can effectively reduce the side reaction products generated by the positive electrode from entering the negative electrode through the diaphragm, can further improve the electronic insulation performance, the temperature resistance performance and the mechanical strength of the diaphragm, and is very important for realizing the lithium ion battery with long cycle life and high safety characteristics.
When the content c of the second amphoteric oxide in the mass of the separator is in the above range, PO can be effectively promoted 2 F 2 - And at the same time, improves the safety performance of the battery.
In some embodiments, the first amphoteric oxide and the second amphoteric oxide are each independently selected from at least one of alumina, zirconia, tungsten oxide, and titanium oxide.
In a preferred embodiment, the first amphoteric oxide and the second amphoteric oxide are each independently selected from at least one of alumina, zirconia, and titania.
In some embodiments, the separator is a polyolefin or non-woven porous composite membrane, and the second amphoteric oxide is coated on at least one side surface of the separator, and the separator includes, but is not limited to, one or more of polypropylene, polyethylene, polyimide, polyvinylidene fluoride.
In some embodiments, the positive electrode active material comprises LiFe 1-x’ M’ x’ PO 4 、LiMn 2-y’ M y’ O 4 And LiNi x Co y Mn z M 1-x-y-z O 2 At least one of sulfide, selenide and halide, wherein M 'is at least one of Mn, mg, co, ni, cu, zn, al, sn, B, ga, cr, sr, V or Ti, M is at least one of Fe, co, ni, mn, mg, cu, zn, al, sn, B, ga, cr, sr, V or Ti, and x' is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, x is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and x+y+z is more than or equal to 1.
In some embodiments, the positive electrode material layer further includes a positive electrode binder, wherein the positive electrode binder is selected from organic polymers, and the molecular weight of the organic polymers is 60-130 ten thousand.
When the positive electrode binder meets the above conditions, the positive electrode material layer and the positive electrode current collector can have good binding force and dynamic performance, and the battery is ensured to have excellent capacity and cycle life.
In some embodiments, the organic polymer comprises a thermoplastic resin such as polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-perfluoroalkyl vinyl ether, a copolymer of ethylene-tetrafluoroethylene, a copolymer of vinylidene fluoride-trifluoroethylene, a copolymer of vinylidene fluoride-trichloroethylene, a copolymer of vinylidene fluoride-fluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, a thermoplastic polyimide, polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, or the like; an acrylic resin; sodium hydroxymethyl cellulose; at least one of nitrile rubber, butadiene rubber, ethylene-propylene rubber, styrene-butadiene-styrene block copolymer or its hydride, ethylene-propylene-diene terpolymer, polyvinyl acetate, syndiotactic-1, 2-polybutadiene, ethylene-ethylene acetate.
In some embodiments, the positive electrode material layer further includes a positive electrode conductive agent including at least one of conductive carbon black, conductive carbon spheres, conductive graphite, conductive carbon fibers, carbon nanotubes, graphene, or reduced graphene oxide.
In some embodiments, the positive electrode active material is selected from LiFe 1-x’ M’ x’ PO 4 、LiMn 2-y’ M y’ O 4 And LiNi x Co y Mn z M 1-x-y-z O 2 Wherein M ' is selected from at least one of Mn, mg, co, ni, cu, zn, al, sn, B, ga, cr, sr, V or Ti, M is selected from at least one of Fe, co, ni, mg, cu, zn, al, sn, B, ga, cr, sr, V or Ti, and 0.ltoreq.x '. Ltoreq.1, 0.ltoreq.y '. Ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.x.ltoreq.1, 0.ltoreq.z.ltoreq.1, x+y+z.ltoreq.1.
In a preferred embodiment, the positive electrode active material may be selected from LiCoO 2 、LiFePO 4 、LiFe 0.8 Mn 0.2 PO 4 、LiMn 2 O 4 、LiNi 0.5 Co 0.2 Mn 0.3 O 2 、LiNi 0.6 Co 0.2 Mn 0.2 O 2 、LiNi 0.8 Co 0.1 Mn 0.1 O 2 、LiNi 0.5 Co 0.2 Mn 0.2 Al 0.1 O 2 、LiNi 0.5 Co 0.2 Al 0.3 O 2 At least one of them.
In some embodiments, the positive electrode further comprises a positive electrode current collector, and the positive electrode material layer is formed on a surface of the positive electrode current collector.
The positive current collector is selected from a metal material that can conduct electrons, preferably, the positive current collector includes at least one of Al, ni, tin, copper, stainless steel, and in a more preferred embodiment, the positive current collector is selected from aluminum foil.
In some embodiments, the negative electrode includes a negative electrode material layer including a negative electrode active material.
In a preferred embodiment, the negative electrode active material includes at least one of a carbon-based negative electrode, a silicon-based negative electrode, a tin-based negative electrode, and a lithium negative electrode. Wherein the carbon-based negative electrode may include graphite, hard carbon, soft carbon, graphene, mesophase carbon microspheres, and the like; the silicon-based anode may include a silicon material, an oxide of silicon, a silicon-carbon composite material, a silicon alloy material, or the like; the tin-based negative electrode may include tin, tin carbon, tin oxygen, and tin metal compounds; the lithium negative electrode may include metallic lithium or a lithium alloy. The lithium alloy may specifically be at least one of a lithium silicon alloy, a lithium sodium alloy, a lithium potassium alloy, a lithium aluminum alloy, a lithium tin alloy, and a lithium indium alloy.
In some embodiments, the negative electrode material layer further comprises a negative electrode binder and a negative electrode conductive agent, and the negative electrode active material, the negative electrode binder and the negative electrode conductive agent are blended to obtain the negative electrode material layer.
The selectable ranges of the negative electrode binder and the negative electrode conductive agent are the same as those of the positive electrode binder and the positive electrode conductive agent, respectively, and are not described in detail herein.
In some embodiments, the negative electrode further includes a negative electrode current collector, and the negative electrode material layer is formed on a surface of the negative electrode current collector.
The negative electrode current collector is selected from a metal material that can conduct electrons, preferably, the negative electrode current collector includes at least one of aluminum, nickel, tin, copper, stainless steel, and in a more preferred embodiment, the negative electrode current collector is selected from copper foil.
In some embodiments, the lithium salt further comprises LiBOB, liDFOB, liBF 4 、LiSbF 6 、LiAsF 6 、LiN(SO 2 CF 3 ) 2 、LiN(SO 2 C 2 F 5 ) 2 、LiC(SO 2 CF 3 ) 3 、LiN(SO 2 F) 2 、LiClO 4 、LiAlCl 4 、LiCF 3 SO 3 、Li 2 B 10 Cl 10 、LiSO 2 F. LiTOP, liDODFP and a lithium salt of a lower aliphatic carboxylic acid.
In some embodiments, the concentration of the lithium salt in the nonaqueous electrolyte is 0.1mol/L to 8mol/L. In a preferred embodiment, the concentration of the lithium salt in the nonaqueous electrolyte is 0.5mol/L to 2.5mol/L. Specifically, in the nonaqueous electrolytic solution, the concentration of the lithium salt may be 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, 2.5mol/L.
In some embodiments, the non-aqueous organic solvent comprises at least one of an ether solvent, a nitrile solvent, a carbonate solvent, a carboxylate solvent, and a sulfone solvent.
In some embodiments, the ether solvent includes cyclic or chain ethers, preferably chain ethers of 3-10 carbon atoms and cyclic ethers of 3-6 carbon atoms, which may be specifically but not limited to 1, 3-Dioxolane (DOL), 1, 4-Dioxane (DX), crown ethers, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH) 3 -THF), 2-trifluoromethyl tetrahydrofuran (2-CF) 3 -THF) at least one of; the chain ether may be, but not limited to, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether. Since the chain ether has a high solvation ability with lithium ions and can improve ion dissociation, dimethoxymethane having a low viscosity and capable of imparting a high ionic conductivity is particularly preferableDiethoxymethane and ethoxymethoxymethane. The ether compound may be used alone, or two or more of them may be used in any combination and ratio. The content of the ether compound is not particularly limited, and is arbitrary within a range that does not significantly impair the effect of the highly compacted lithium ion battery of the present invention, and the nonaqueous solvent is usually 1% or more, preferably 2% or more, more preferably 3% or more by volume, and is usually 30% or less, preferably 25% or less, more preferably 20% or less by volume, in 100% by volume. When two or more ether compounds are used in combination, the total amount of the ether compounds may be set to satisfy the above range. When the content of the ether compound is within the above preferred range, the effect of improving the ionic conductivity due to the increase in the dissociation degree of lithium ions and the decrease in the viscosity of the chain ether can be easily ensured. In addition, when the negative electrode active material is a carbon-based material, the co-intercalation phenomenon caused by the chain ether and lithium ions can be suppressed, and thus the input/output characteristics and the charge/discharge rate characteristics can be brought into appropriate ranges.
In some embodiments, the nitrile solvent may be, but is not limited to, at least one of acetonitrile, glutaronitrile, malononitrile.
In some embodiments, the carbonate-based solvent includes a cyclic carbonate or a chain carbonate, which may be specifically but not limited to at least one of Ethylene Carbonate (EC), propylene Carbonate (PC), gamma-butyrolactone (GBL), butylene Carbonate (BC); the chain carbonate may be, but not limited to, at least one of dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), dipropyl carbonate (DPC). The content of the cyclic carbonate is not particularly limited, and is arbitrary within a range that does not significantly impair the effect of the lithium ion battery of the present invention, but in the case of using one of them alone, the lower limit of the content is usually 3% by volume or more, preferably 5% by volume or more, relative to the total amount of the solvent of the nonaqueous electrolytic solution. By setting the range, it is possible to avoid a decrease in conductivity due to a decrease in dielectric constant of the nonaqueous electrolyte solution, and it is easy to achieve a good range of high-current discharge characteristics, stability with respect to the negative electrode, and cycle characteristics of the nonaqueous electrolyte battery. The upper limit is usually 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. By setting the range, the oxidation/reduction resistance of the nonaqueous electrolytic solution can be improved, thereby contributing to improvement of stability at high-temperature storage. The content of the chain carbonate is not particularly limited, but is usually 15% by volume or more, preferably 20% by volume or more, and more preferably 25% by volume or more, based on the total amount of the solvent of the nonaqueous electrolytic solution. In addition, the volume ratio is usually 90% or less, preferably 85% or less, and more preferably 80% or less. By setting the content of the chain carbonate in the above range, the viscosity of the nonaqueous electrolytic solution can be easily set to an appropriate range, and the decrease in the ionic conductivity can be suppressed, thereby contributing to the improvement in the output characteristics of the nonaqueous electrolyte battery. When two or more kinds of chain carbonates are used in combination, the total amount of the chain carbonates may be set to satisfy the above range.
In some embodiments, it may also be preferable to use a chain carbonate having a fluorine atom (hereinafter simply referred to as "fluorinated chain carbonate"). The number of fluorine atoms in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. In the case where the fluorinated chain carbonate has a plurality of fluorine atoms, these fluorine atoms may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated chain carbonate include fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, and fluorinated diethyl carbonate derivatives.
The carboxylic acid ester solvent includes a cyclic carboxylic acid ester and/or a chain carbonate. Examples of the cyclic carboxylic acid ester include: at least one of gamma-butyrolactone, gamma-valerolactone and delta-valerolactone. Examples of the chain carbonate include, for example: at least one of Methyl Acetate (MA), ethyl Acetate (EA), propyl acetate (EP), butyl acetate, propyl Propionate (PP) and butyl propionate.
In some embodiments, the sulfone-based solvent includes cyclic sulfones and chain sulfones, preferably compounds having generally 3 to 6 carbon atoms, preferably 3 to 5 carbon atoms, in the case of cyclic sulfones, and generally 2 to 6 carbon atoms, preferably 2 to 5 carbon atoms, in the case of chain sulfones. The content of the sulfone-based solvent is not particularly limited, and is arbitrary within a range that does not significantly impair the effect of the lithium ion battery of the present invention, and is usually 0.3% or more by volume, preferably 0.5% or more by volume, more preferably 1% or more by volume, and is usually 40% or less by volume, preferably 35% or less by volume, more preferably 30% or less by volume, based on the total amount of the solvent of the nonaqueous electrolyte. When two or more sulfone solvents are used in combination, the total amount of sulfone solvents may be set to satisfy the above range. When the content of the sulfone-based solvent is within the above range, a nonaqueous electrolytic solution excellent in high-temperature storage stability tends to be obtained.
In a preferred embodiment, the non-aqueous organic solvent includes at least one of ethylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, propylene carbonate, butyl acetate, gamma-butyrolactone, propyl propionate, ethyl butyrate, methyl acetate, ethyl fluoroacetate, and fluoroether.
In a preferred embodiment, the nonaqueous organic solvent is a mixture of cyclic carbonates and chain carbonates.
In some embodiments, the additive comprises at least one of a cyclic sulfate compound, a sultone compound, a cyclic carbonate compound, a phosphate compound, a borate compound, and a nitrile compound;
the content of the additive is 0.01% -30% based on 100% of the total mass of the nonaqueous electrolyte.
In some embodiments, the cyclic sulfate compound is selected from the group consisting of vinyl sulfate, propylene sulfate, vinyl methyl sulfate,、、、、At least one of (a) and (b);
the sultone compound is selected from 1, 3-propane sultone, 1, 4-butane sultone, 1, 3-propylene sultone,At least one of (a) and (b);
the cyclic carbonate compound is at least one selected from ethylene carbonate, methylene ethylene carbonate, fluoroethylene carbonate, trifluoromethyl ethylene carbonate, bifluoroethylene carbonate and a compound shown in a structural formula 1:
Structure 1
In the structural formula 1, R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently selected from one of a hydrogen atom, a halogen atom, a C1-C5 group;
the phosphate compound is at least one selected from tris (trimethylsilane) phosphate, tris (trimethylsilane) phosphite or a compound shown in a structural formula 2:
structure 2
In the structural formula 2, R 31 、R 32 、R 33 Each independently selected from the group consisting of C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, -Si (C) m H 2m+1 ) 3 M is a natural number of 1 to 3, and R 31 、R 32 、R 33 At least one of them is an unsaturated hydrocarbon group;
in a preferred embodiment, the phosphate compound represented by the structural formula 2 may be at least one of tripropylethyl phosphate, dipropargyl methyl phosphate, dipropargyl ethyl phosphate, dipropargyl propyl phosphate, dipropargyl trifluoromethyl phosphate, dipropargyl-2, 2-trifluoroethyl phosphate, dipropargyl-3, 3-trifluoropropyl phosphate, dipropargyl hexafluoroisopropyl phosphate, triallyl phosphate, diallyl methyl phosphate, diallyl ethyl phosphate, diallyl propyl phosphate, diallyl trifluoromethyl phosphate, diallyl-2, 2-trifluoroethyl phosphate, diallyl-3, 3-trifluoropropyl phosphate, diallyl hexafluoroisopropyl phosphate;
The borate compound is at least one selected from tri (trimethylsilane) borate and tri (triethylsilane) borate;
the nitrile compound is at least one selected from succinonitrile, glutaronitrile, ethylene glycol bis (propionitrile) ether, hexanedinitrile, adiponitrile, pimelic nitrile, suberonitrile, nonyldinitrile and decyldinitrile.
In other embodiments, the additive may further comprise other additives that improve battery performance: for example, additives that enhance the safety performance of the battery, specifically flame retardant additives such as fluorophosphate and cyclophosphazene, or overcharge-preventing additives such as t-amyl benzene and t-butyl benzene.
In general, the content of any one of the optional substances in the additive in the nonaqueous electrolytic solution is 10% or less, preferably 0.1 to 5%, more preferably 0.1 to 2%, unless otherwise specified. Specifically, the content of any optional substance in the additive may be 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 7.8%, 8.5%, 9%, 9.5%, 10%.
In some embodiments, when the additive is selected from fluoroethylene carbonate, the fluoroethylene carbonate content is 0.05% -30% based on 100% of the total mass of the nonaqueous electrolytic solution.
The invention is further illustrated by the following examples.
Table 1 examples and comparative examples designs of parameters
Example 1
This embodiment is for explaining the lithium ion battery disclosed by the invention, comprising a positive electrode, a negative electrode, a nonaqueous electrolyte and a separator arranged between the positive electrode and the negative electrode, wherein:
the positive electrode comprises a positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2 A positive electrode material layer formed by mixing conductive carbon black Super-P and a positive electrode binder, wherein the surface of the positive electrode material layer contains a first amphoteric oxide with the mass shown in table 1;
the negative electrode comprises a negative electrode material layer prepared by mixing negative electrode active materials of artificial graphite, conductive carbon black Super-P, a binder Styrene Butadiene Rubber (SBR) and carboxymethyl cellulose (CMC) in a mass ratio of 94:1:2.5:2.5;
the non-aqueous electrolyte comprises a non-aqueous organic solvent and PO 2 F 2 - And a lithium salt including lithium hexafluorophosphate, the organic solvent including Ethylene Carbonate (EC), diethyl carbonate (DEC) and Ethyl Methyl Carbonate (EMC) in a mass ratio ec:dec:emc=1:1:1, the lithium hexafluorophosphate (LiPF) in the nonaqueous electrolytic solution 6 ) Concentration and PO 2 F 2 - The content is shown in Table 1.
The separator was a PE separator, the surface of which contained a second amphoteric oxide of the mass shown in the examples of table 1.
Examples 2 to 31
Examples 2 to 31 are for illustrating the lithium ion battery disclosed in the present invention, and are mostly the same as example 1, except that:
positive electrode active materials and LiPF were used as shown in examples 2 to 31 in Table 1 6 Concentration, PO 2 F 2 - The mass content of (a) the mass content of (b) the other additives, the mass content of (b) the first amphoteric oxide and the mass content of (c) the second amphoteric oxide.
Comparative examples 1 to 27
Comparative examples 1 to 27 are for comparative illustration of the lithium ion battery disclosed in the present invention, and are mostly the same as example 1, except that:
positive electrode active materials, liPF, shown in examples 1 to 27 in Table 1 were used 6 Concentration, PO 2 F 2 - The mass content of the first amphoteric oxide/other oxide, the mass content of the second amphoteric oxide/other oxide, and the mass content thereof.
The lithium ion batteries of the above examples and comparative examples may be prepared by a known method, and are not particularly limited. Examples thereof include: liPO to be synthesized by a known method 2 F 2 A method of adding to an electrolyte; in advance, active materials, electrode plates, separators and other battery components are made to coexist, and LiPF is used 6 To generate PO in the system when the battery is assembled by the electrolyte of (a) 2 F 2 - Is a method of (2). In the present embodimentAny method may be used.
As a means for measuring PO in the above lithium ion battery 2 F 2 - The method of the content of (2) is not particularly limited, and any known method may be used. Specific examples thereof include: ion chromatography, 19 F NMR, and the like.
Performance testing
The following performance tests were performed on the above lithium ion batteries:
1. and (3) testing the cycle performance:
the lithium ion batteries of the examples and the comparative examples were charged at a rate of 1C and discharged at a rate of 1C at 25C, the capacity of the battery charged and discharged for the first time was recorded, and a full charge discharge cycle test was performed within a charge-discharge cut-off voltage (e.g., 3V to 4.2V) until the capacity of the lithium ion battery was attenuated to 80% of the initial capacity, and the initial capacity and the number of cycles of the battery were recorded.
2. Cell DCIR test:
the battery DCIR test procedure was: at 25 ℃, the lithium ion secondary battery is placed for 5 minutes, is charged to an upper limit cut-off voltage (such as 4.2V) with a constant current of 1C, is charged to a current of less than or equal to 0.05C at a constant voltage, the state of charge (SOC) of the battery is 100%, is placed for 5 minutes, is discharged with a constant current of 1C, and the state of charge (SOC) of the lithium ion secondary battery is adjusted to 50%. After the rest for 30 minutes, the discharge was performed at a rate of 1C for 10 seconds, the voltage before the discharge was designated U1, and the voltage after the discharge was designated U2. Dcir= (U1-U2)/1C of the battery.
(1) The test results obtained in examples 1 to 12 and comparative examples 1, 14 to 27 are filled in Table 2.
TABLE 2
From the test results obtained in examples 1 to 12 and comparative examples 1, 14 to 27, it is understood thatWhen the molar concentration a of lithium hexafluorophosphate in the nonaqueous electrolyte solution and PO in the nonaqueous electrolyte solution are 2 F 2 - When the mass percentage content m, the mass percentage content b of the first amphoteric oxide and the mass percentage content c of the second amphoteric oxide in the positive electrode material layer satisfy the condition that m (10 x b+c)/a is less than or equal to 30, a is less than or equal to 0.5 and less than or equal to 1.5,0.01, m is less than or equal to 0.8,0.01 and less than or equal to 2, c is less than or equal to 0.5 and less than or equal to 30, the obtained lithium ion battery has higher initial capacity, lower impedance and longer cycle life, and is presumably because lithium hexafluorophosphate can react to generate PO in the battery formation process 2 F 2 - ，PO 2 F 2 - Further decomposing on the surface of the positive electrode active material and forming a passivation film by being matched with the first amphoteric oxide, wherein the first amphoteric oxide and the second amphoteric oxide on the diaphragm in the positive electrode material layer can be regulated and controlled, and meanwhile, the content of lithium hexafluorophosphate and PO are controlled 2 F 2 - The quality of the passivation film on the surface of the positive electrode material layer is adjusted, so that the passivation film has more stable property, the passivation film is prevented from being broken in the charge-discharge cycle of the battery, the cycle stability of the nonaqueous electrolyte and the positive electrode active material is ensured, and the cycle performance of the battery is effectively improved.
As is clear from the test results of examples 1 to 12, when the molar concentration a of lithium hexafluorophosphate in the nonaqueous electrolytic solution and PO in the nonaqueous electrolytic solution are 2 F 2 - The mass percentage content m of the first amphoteric oxide and the mass percentage content b of the second amphoteric oxide of the positive electrode material layer further satisfy the condition that m (10 x b+c)/a is less than or equal to 10, a is less than or equal to 0.7 and less than or equal to 1.2,0.05, m is less than or equal to 0.5,0.03 and less than or equal to 1, c is less than or equal to 3 and less than or equal to 20, the initial capacity of the battery is further improved, the impedance of the battery is reduced, the cycle life of the lithium ion battery is prolonged, and the passivation film on the surface of the positive electrode material layer obtained at the moment is presumed to have better compactness and lower thickness, the capacity loss of the lithium ion battery is reduced, and the cycle performance of the lithium ion battery is improved.
As can be seen from the test results of comparative examples 14 to 27, even if the nonaqueous electrolyte isMolar concentration of lithium hexafluorophosphate in solution a, PO in the nonaqueous electrolyte 2 F 2 - The mass percentage content m of the first amphoteric oxide accounting for the mass of the positive electrode material layer, the mass percentage content b of the second amphoteric oxide accounting for the mass of the separator and the mass percentage content c of the second amphoteric oxide meet the limit that the condition 0.1 is less than or equal to m (10 x b+c)/a is less than or equal to 30, but when the value a, the value m, the value b or the value c does not meet the limit of the range, the lithium ion battery still does not have higher initial capacity and better cycle performance, and the value a, the value m, the value b or the value c have stronger relevance in improving the performance of the lithium ion battery. Similarly, when the value of a, m, b or c satisfies the range limit, but the value of m (10×b+c)/a does not satisfy the above-mentioned predetermined condition, the improvement in the battery performance is not significant.
(2) The test results obtained in example 1 and comparative examples 5 to 13 are shown in Table 3.
TABLE 3 Table 3
As can be seen from the test results of examples 1 and comparative examples 5-6, PO was caused either by the absence of the first amphoteric oxide or the absence of the second amphoteric oxide 2 F 2 - The amount drops to a greater extent, and at the same time, results in an increase in the impedance of the battery and a decrease in the number of cycles. As is evident from the test results of example 1 and comparative examples 7 to 13, when other oxides are used instead of the first amphoteric oxide and/or the second amphoteric oxide, the LiPF is modified 6 Exhibit little or no reactivity, so that little or no PO is formed 2 F 2 - The condition limit of the application is not satisfied, and the improvement of the battery cycle performance is also not facilitated.
(3) The test results obtained in examples 1 and 13 to 21 are filled in Table 4.
TABLE 4 Table 4
As shown by the test results of examples 1 and 13-21, when different amphoteric oxides or combinations thereof are adopted as the first amphoteric oxide and the second amphoteric oxide, as long as the value a, the value m, the value b or the value c meets the condition of 0.1 m (10 x b+c)/a is less than or equal to 30, a is less than or equal to 0.5 and less than or equal to 1.5,0.01, m is less than or equal to 0.8,0.01 and less than or equal to 2, and c is less than or equal to 0.5 and less than or equal to 30, the obtained lithium ion battery has higher initial capacity and better cycle performance, which indicates that the lithium ion battery system provided by the application has universality for different amphoteric oxides, and also indicates the necessity of the adoption of the amphoteric oxides for the lithium ion battery system.
(4) The test results obtained in examples 1, 20 to 22 and comparative examples 2 to 4 are shown in Table 5.
TABLE 5
As can be seen from the test results of examples 1 and comparative examples 2 to 4, the improvement effect of adding Vinylene Carbonate (VC), vinyl sulfate (DTD) or fluoroethylene carbonate (FEC) as a film forming additive to the lithium ion electrolyte is obviously inferior to the improvement of the performance of the battery system provided by the application to the lithium ion battery.
As shown by the test results of examples 1 and 20-22, in the battery system provided by the application, ethylene carbonate (VC), ethylene sulfate (DTD) or fluoroethylene carbonate (FEC) are additionally added, so that the battery impedance can be further reduced, the cycle life of the battery can be prolonged, and the improvement mechanism of other additives on the battery performance and PO can be illustrated 2 F 2 - There is a certain difference, and the two have complementary effect on film formation, so that the quality of the interfacial film on the surface of the positive electrode material layer is improved.
(5) The test results obtained in examples 1, 23 to 31 are shown in Table 6.
TABLE 6
As shown by the test results of examples 1 and 23-31, when the batteries are made of different positive electrode active materials, and the values of a, m, b or c meet the conditions of 0.1 m (10 x b+c)/a is less than or equal to 30, and 0.5 a is less than or equal to 1.5,0.01 m is less than or equal to 0.8,0.01 b is less than or equal to 2,0.5 c is less than or equal to 30, the battery has high initial capacity, lower battery impedance and excellent cycle performance, and the battery can have high energy density and long cycle life, so that the battery system provided by the application is suitable for different positive electrode active materials.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims (9)

1. The lithium ion battery is characterized by comprising a positive electrode, a negative electrode, a nonaqueous electrolyte and a diaphragm arranged between the positive electrode and the negative electrode, wherein the positive electrode comprises a positive electrode material layer containing a positive electrode active material, the surface of the positive electrode material layer contains a first amphoteric oxide, the surface of the diaphragm contains a second amphoteric oxide, and the nonaqueous electrolyte comprises a nonaqueous organic solvent and PO 2 F 2 - And a lithium salt comprising lithium hexafluorophosphate;
the lithium ion battery meets the following conditions:
m is more than or equal to 0.1 and less than or equal to (10 x b+c)/a is more than or equal to 30, a is more than or equal to 0.5 and less than or equal to 1.5,0.05, m is more than or equal to 0.5, b is more than or equal to 0.01 and less than or equal to 2, and c is more than or equal to 0.5 and less than or equal to 30;
wherein a is the molar concentration of lithium hexafluorophosphate in the nonaqueous electrolyte, and the unit is mol/L;
m is PO in the nonaqueous electrolyte 2 F 2 - The mass percentage of (2) is as follows;
b is the percentage content of the first amphoteric oxide in the mass of the positive electrode material layer, and the unit is;
and c is the percentage content of the second amphoteric oxide in the mass of the diaphragm, and the unit is percent.
2. The lithium ion battery of claim 1, wherein the lithium ion battery meets the following conditions:
0.5≤m*(10*b+c)/a≤10。
3. the lithium ion battery according to claim 1, wherein the molar concentration a of lithium hexafluorophosphate in the nonaqueous electrolytic solution is 0.7 to 1.2mol/L.
4. The lithium ion battery of claim 1, wherein the first amphoteric oxide comprises 0.03% -1% of the positive electrode material layer by mass b.
5. The lithium ion battery according to claim 1, wherein the second amphoteric oxide accounts for 3-20% of the mass of the separator.
6. The lithium ion battery of claim 1, wherein the first amphoteric oxide and the second amphoteric oxide are each independently selected from at least one of alumina, zirconia, tungsten oxide, and titania.
7. The lithium ion battery of claim 1, wherein the positive electrode active material comprises LiFe 1-x’ M’ x’ PO 4 、LiMn 2-y’ M y’ O 4 And LiNi x Co y Mn z M 1-x-y-z O 2 At least one of sulfide, selenide and halide, wherein M ' is selected from at least one of Mn, mg, co, ni, cu, zn, al, sn, B, ga, cr, sr, V or Ti, M is selected from at least one of Fe, co, ni, mn, mg, cu, zn, al, sn, B, ga, cr, sr, V or Ti, and x ' is more than or equal to 0 and less than or equal to 1, y ' is more than or equal to 0 and less than or equal to 1, and y is more than or equal to 0 and less than or equal to 1 1，0≤x≤1，0≤z≤1，x+y+z≤1。
8. The lithium ion battery according to claim 1, wherein the nonaqueous electrolytic solution further comprises an additive including at least one of a cyclic sulfate compound, a sultone compound, a cyclic carbonate compound, a phosphate compound, a borate compound, and a nitrile compound;
the content of the additive is 0.01-30% based on 100% of the total mass of the nonaqueous electrolyte.
9. The lithium ion battery of claim 8, wherein the cyclic sulfate compound is selected from the group consisting of vinyl sulfate, propylene sulfate, vinyl methyl sulfate, At least one of (a) and (b);
the sultone compound is selected from 1, 3-propane sultone, 1, 4-butane sultone, 1, 3-propylene sultone,At least one of (a) and (b);
the cyclic carbonate compound is at least one selected from ethylene carbonate, methylene ethylene carbonate, fluoroethylene carbonate, trifluoromethyl ethylene carbonate, bifluoroethylene carbonate and a compound shown in a structural formula 1:
in the structural formula 1, R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently selected from one of a hydrogen atom, a halogen atom, a C1-C5 group;
The phosphate compound is at least one selected from tris (trimethylsilane) phosphate, tris (trimethylsilane) phosphite or a compound shown in a structural formula 2:
in the structural formula 2, R 31 、R 32 、R 33 Each independently selected from the group consisting of C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, -Si (C) m H 2m+1 ) 3 M is a natural number of 1 to 3, and R 31 、R 32 、R 33 At least one of them is an unsaturated hydrocarbon group;
the borate compound is at least one selected from tri (trimethylsilane) borate and tri (triethylsilane) borate;
the nitrile compound is at least one selected from succinonitrile, glutaronitrile, ethylene glycol bis (propionitrile) ether, hexanedinitrile, adiponitrile, pimelic nitrile, suberonitrile, nonyldinitrile and decyldinitrile.
CN202211570289.1A 2022-12-08 2022-12-08 Lithium ion battery Active CN115663286B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202211570289.1A CN115663286B (en) 2022-12-08 2022-12-08 Lithium ion battery
PCT/CN2023/127475 WO2024120053A1 (en) 2022-12-08 2023-10-30 Lithium-ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211570289.1A CN115663286B (en) 2022-12-08 2022-12-08 Lithium ion battery

Publications (2)

Publication Number Publication Date
CN115663286A CN115663286A (en) 2023-01-31
CN115663286B true CN115663286B (en) 2023-09-08

Family

ID=85017201

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211570289.1A Active CN115663286B (en) 2022-12-08 2022-12-08 Lithium ion battery

Country Status (2)

Country Link
CN (1) CN115663286B (en)
WO (1) WO2024120053A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115663286B (en) * 2022-12-08 2023-09-08 深圳新宙邦科技股份有限公司 Lithium ion battery
CN118630319A (en) * 2024-08-14 2024-09-10 广州天赐高新材料股份有限公司 An electrolyte and includes battery of the electrolyte

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0374061A (en) * 1989-05-16 1991-03-28 Toshiba Corp Nonaqueous electrolyte secondary battery
EP2426773A2 (en) * 2010-09-03 2012-03-07 GS Yuasa International Ltd. Battery
JP2013161706A (en) * 2012-02-07 2013-08-19 Asahi Glass Co Ltd Nonaqueous electrolytic solution for secondary battery, and lithium ion secondary battery
CN103477493A (en) * 2011-03-29 2013-12-25 三洋电机株式会社 Non-aqueous electrolyte secondary battery
CN110265716A (en) * 2019-06-13 2019-09-20 东莞维科电池有限公司 A kind of lithium-ion battery electrolytes and lithium ion battery
CN112436150A (en) * 2020-12-09 2021-03-02 衡阳力赛储能有限公司 Low-temperature lithium iron phosphate cylindrical battery and manufacturing method thereof

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4991996B2 (en) * 2005-11-14 2012-08-08 パナソニック株式会社 Non-aqueous electrolyte secondary battery
CN107482247A (en) * 2017-08-29 2017-12-15 江苏楚汉新能源科技有限公司 A kind of high-voltage lithium ion batteries
CN114695944A (en) * 2020-12-28 2022-07-01 深圳新宙邦科技股份有限公司 Lithium ion battery
CN115663286B (en) * 2022-12-08 2023-09-08 深圳新宙邦科技股份有限公司 Lithium ion battery

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0374061A (en) * 1989-05-16 1991-03-28 Toshiba Corp Nonaqueous electrolyte secondary battery
EP2426773A2 (en) * 2010-09-03 2012-03-07 GS Yuasa International Ltd. Battery
CN103477493A (en) * 2011-03-29 2013-12-25 三洋电机株式会社 Non-aqueous electrolyte secondary battery
JP2013161706A (en) * 2012-02-07 2013-08-19 Asahi Glass Co Ltd Nonaqueous electrolytic solution for secondary battery, and lithium ion secondary battery
CN110265716A (en) * 2019-06-13 2019-09-20 东莞维科电池有限公司 A kind of lithium-ion battery electrolytes and lithium ion battery
CN112436150A (en) * 2020-12-09 2021-03-02 衡阳力赛储能有限公司 Low-temperature lithium iron phosphate cylindrical battery and manufacturing method thereof

Also Published As

Publication number Publication date
WO2024120053A1 (en) 2024-06-13
CN115663286A (en) 2023-01-31

Similar Documents

Publication Publication Date Title
CN114497692B (en) Secondary battery
CN114447295B (en) Lithium ion battery
CN114464887B (en) Secondary battery
CN115117452B (en) Lithium ion battery
US20120219866A1 (en) Nonaqueous electrolytic solution and nonaqueous-electrolyte battery employing the same
CN114639872B (en) Lithium ion battery
CN115663286B (en) Lithium ion battery
CN118610582A (en) Nonaqueous electrolyte and secondary battery
CN115020813B (en) Lithium ion battery
CN114361588B (en) Lithium ion battery
CN115036572A (en) Lithium secondary battery
CN115020815A (en) Lithium ion battery
CN116315090A (en) Lithium ion battery
CN114975873B (en) Positive plate and lithium ion battery
CN116435595A (en) Lithium ion battery
CN116072964A (en) Lithium ion battery
CN117790905A (en) Lithium ion battery
CN117728026A (en) Lithium ion battery
CN117650276A (en) Nonaqueous electrolyte and lithium ion battery
CN116454381A (en) High-voltage lithium ion battery
WO2023104038A1 (en) Secondary battery
CN117477027A (en) Nonaqueous electrolyte and secondary battery
CN115911545A (en) Non-aqueous electrolyte and battery
CN118472377A (en) Nonaqueous electrolyte and lithium ion battery
CN116190788A (en) Nonaqueous electrolyte and lithium ion battery

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
GR01 Patent grant
GR01 Patent grant