CN115832283A - Composite positive electrode active material - Google Patents
Composite positive electrode active material Download PDFInfo
- Publication number
- CN115832283A CN115832283A CN202111473505.6A CN202111473505A CN115832283A CN 115832283 A CN115832283 A CN 115832283A CN 202111473505 A CN202111473505 A CN 202111473505A CN 115832283 A CN115832283 A CN 115832283A
- Authority
- CN
- China
- Prior art keywords
- active material
- positive electrode
- electrode active
- limn
- polarization
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000007774 positive electrode material Substances 0.000 title claims abstract description 75
- 239000002131 composite material Substances 0.000 title claims abstract description 34
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 53
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 53
- 230000010287 polarization Effects 0.000 claims abstract description 47
- 239000010416 ion conductor Substances 0.000 claims abstract description 36
- 229910015645 LiMn Inorganic materials 0.000 claims abstract description 35
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 51
- 238000003825 pressing Methods 0.000 claims description 24
- 238000003756 stirring Methods 0.000 claims description 18
- 229920002873 Polyethylenimine Polymers 0.000 claims description 16
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 11
- 239000011248 coating agent Substances 0.000 claims description 8
- 238000000576 coating method Methods 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 8
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 6
- 239000011230 binding agent Substances 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- 229910013716 LiNi Inorganic materials 0.000 claims description 5
- 229910009178 Li1.3Al0.3Ti1.7(PO4)3 Inorganic materials 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000011247 coating layer Substances 0.000 claims description 3
- 229910052744 lithium Inorganic materials 0.000 claims description 3
- 229920001610 polycaprolactone Polymers 0.000 claims description 3
- 239000004632 polycaprolactone Substances 0.000 claims description 3
- 229920001601 polyetherimide Polymers 0.000 claims description 3
- 239000011149 active material Substances 0.000 claims 2
- 239000006183 anode active material Substances 0.000 abstract description 3
- 230000002035 prolonged effect Effects 0.000 abstract description 3
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 description 21
- 238000002156 mixing Methods 0.000 description 15
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 11
- 229910015855 LiMn0.7Fe0.3PO4 Inorganic materials 0.000 description 11
- 239000002245 particle Substances 0.000 description 10
- 238000001035 drying Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 4
- 238000004146 energy storage Methods 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- 229910010710 LiFePO Inorganic materials 0.000 description 3
- 239000002033 PVDF binder Substances 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000006258 conductive agent Substances 0.000 description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000006230 acetylene black Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- -1 Polyethylene Polymers 0.000 description 1
- 230000004308 accommodation Effects 0.000 description 1
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 239000006182 cathode active material Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- ILXAVRFGLBYNEJ-UHFFFAOYSA-K lithium;manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[O-]P([O-])([O-])=O ILXAVRFGLBYNEJ-UHFFFAOYSA-K 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- 239000005486 organic electrolyte Substances 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Battery Electrode And Active Subsutance (AREA)
Abstract
The application provides a composite positive active material comprising LiMn x Fe 1‑x PO 4 (0<x<1) A lithium ion conductor and a positive electrode active material having small polarization; the lithium ion conductor and the small-polarization positive active material are distributed in LiMn x Fe 1‑x PO 4 (0<x<1) Of the surface of (a). The composite anode active material has the advantages of small polarization, good conductivity, good multiplying power performance and prolonged cycle life of the battery cell.
Description
Technical Field
The application relates to a composite positive electrode active material, belonging to the technical field of electrochemical batteries.
Background
Lithium ion secondary batteries have been widely used in the fields of digital products, electric vehicles, energy storage base stations, and the like. With the large number of applications of lithium ion secondary batteries, higher requirements are placed on positive electrode active materials of lithium ion secondary batteries. The positive active material is a core factor directly influencing the overall performance of the battery, and an ideal lithium ion secondary battery needs to have high energy density, stable cycle performance and rate capability, good safety and lower economic cost.
In the positive active material of the lithium ion secondary battery, the lithium manganese iron phosphate has the advantages of both lithium iron phosphate and lithium manganese phosphate, and the theoretical capacity of the lithium manganese iron phosphate is the same as that of the lithium iron phosphate and is 170mAh/g; however, lithium manganese iron phosphate is comparable to Li/Li + The electrode potential of (2) is 4.1V, which is much higher than 3.4V of lithium iron phosphate, and is positioned in a stable electrochemical window of an organic electrolyte system. The higher voltage platform of the lithium manganese iron phosphate enables the theoretical energy density of the lithium manganese iron phosphate to be 15-20% higher than that of lithium iron phosphate under the same condition.
However, the lithium manganese iron phosphate has poor conductivity and large polarization, and influences the electrochemical performance of the battery cell; and the lithium manganese iron phosphate has poor dynamic performance at low SOC (state of charge), which limits the further wide application of lithium manganese iron phosphate.
Disclosure of Invention
In view of the above technical problem, the present application provides a composite cathode active material, which not only can enhance the conductivity of lithium iron manganese phosphate and solve the problem of large polarization, but also can improve the dynamic performance of the battery in low SOC and increase the cycling stability.
In a first aspect, the present application provides a composite positive electrode active material, comprising: liMn x Fe 1-x PO 4 (0<x<1) A lithium ion conductor and a positive electrode active material having small polarization; the lithium ion conductor and the small-polarization positive active material are distributed in LiMn x Fe 1-x PO 4 (0<x<1) Of (2) is provided.
The lithium ion conductor has high conductivity, can quickly conduct lithium ions and can improve LiMn x Fe 1-x PO 4 (0<x<1) The conductivity of (a); the positive electrode active material with small polarization can reduce LiMn x Fe 1-x PO 4 (0<x<1) The lithium ion conductor and the positive electrode active material with small polarization are distributed in the LiMn x Fe 1-x PO 4 (0<x<1) The surface energy of (2) improves the multiplying power performance of the battery core.
In some embodiments, the lithium ion conductor is polyethyleneimine PEI, polycaprolactone (C) 6 H 10 O 2 )n、Li 7 La 3 Zr 2 O 12 、Li 10 Ge(PS 6 ) 2 、Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 One or more of the above.
These materials are lithium ion conductors that can be suitable for use in a variety of situations, either alone or in combination, to enhance conductivity.
In some embodiments, the small polarization positive active material is nano lithium iron phosphate, and/or nano LiNi x Co y Mn z O 2 (x+y+z＝1,0≤x≤0.6)。
Nano lithium iron phosphate and/or nano LiNi x Co y Mn z O 2 (x + y + z =1, 0. Ltoreq. X. Ltoreq.0.6) not only can reduce LiMn x Fe 1-x PO 4 (0<x<1) The polarization of the battery can be improved at the same time, and the dynamic performance of the battery at low SOC can be improved.
In some embodiments, liMn x Fe 1-x PO 4 (0<x<1) Lithium ion conductorThe molar ratio of the bulk to the low-polarization positive active material is 96-98:1-2:1-2.
The positive active material mixed according to the molar ratio range has higher rate performance and capacity retention rate.
In some embodiments, liMn x Fe 1-x PO 4 (0<x<1) Dv50 of (3): 7-13 μm, and the Dv50: 20-100nm of the positive electrode active material with small polarization.
LiMn x Fe 1-x PO 4 When the Dv50 of the positive electrode active material with small polarization is in the range, the two materials can form better particle grading relationship, and can be fully contacted with each other, thereby being beneficial to the transmission of lithium ions among particles.
In a second aspect, the present application provides a positive electrode sheet, which is characterized by comprising the composite positive electrode active material.
In the composite positive electrode active material, the lithium ion conductor has strong conductivity and can improve LiMn x Fe 1-x PO 4 (0<x<1) The conductivity of (a); the positive electrode active material with small polarization can reduce LiMn x Fe 1-x PO 4 (0<x<1) The lithium ion conductor and the positive electrode active material with small polarization are distributed in the LiMn x Fe 1-x PO 4 (0<x<1) The positive pole piece prepared on the surface of the battery core can improve the multiplying power performance of the battery core.
In some embodiments, cold compaction of the positive pole piece: 3.45-3.5g/cm 3 。
The cold-pressed density of the positive pole piece is moderate, so that the positive pole piece can be ensured to be in close contact with the positive active material particles, and has better wettability to the electrolyte.
In a third aspect, the application provides a method for preparing the positive electrode plate, which includes the steps of dissolving the composite positive electrode active material, the binder and the conductive carbon in the N-methylpyrrolidone, uniformly stirring, coating and cold pressing.
Since the lithium ion conductor has high conductivity, liMn can be increased x Fe 1-x PO 4 (0<x<1) The conductivity of (2); the positive electrode active material with small polarization can reduce LiMn x Fe 1-x PO 4 (0<x<1) Thus, a lithium ion conductor and a positive electrode active material having small polarization are distributed in LiMn x Fe 1-x PO 4 (0<x<1) The positive pole piece prepared by the composite positive active material formed on the surface can improve the multiplying power performance of the battery cell.
In some embodiments, the composite positive electrode active material comprises 96-97% by weight of the coated coating layer.
The composite anode active material is used as the main component of the coating and can effectively improve the LiMn x Fe 1-x PO 4 (0<x<1) And reduce its polarization.
In some embodiments, the cold pressing pressure: 40-60T.
When the cold pressing pressure is within the range, the particles can be in close contact, the lithium ions can be transmitted among the particles, the internal resistance is reduced, the polarization loss is reduced, the cycle life of the battery is prolonged, and the utilization rate of the lithium ion secondary battery is improved.
In a fourth aspect, the present application provides a secondary battery, including the above-mentioned positive electrode sheet.
Since the lithium ion conductor has high conductivity, liMn can be increased x Fe 1-x PO 4 (0<x<1) The conductivity of (2); the positive electrode active material with small polarization can reduce LiMn x Fe 1-x PO 4 (0<x<1) Thus, a secondary battery containing a lithium ion conductor and a positive active material having small polarization has high rate performance.
In a fifth aspect, the present application provides a battery module including the secondary battery described above.
Since batteries containing lithium ion conductors and a positive electrode active material with low polarization have high rate performance, battery modules composed of such secondary batteries have high rate performance.
In a sixth aspect, the present application provides a battery pack including the battery module described above.
A battery pack having a plurality of battery modules with high rate capability can rapidly transfer energy.
In a seventh aspect, the present application provides an electric device, including the above battery pack.
Because the battery pack with high rate capability is contained, the electric device can quickly obtain high-efficiency electric energy, timely respond and support other components to play functions, and the safety of the electric device in operation is guaranteed.
The foregoing description is only an overview of the technical solutions of the present application, and the present application can be implemented according to the content of the description in order to make the technical means of the present application more clearly understood, and the following detailed description of the present application is given in order to make the above and other objects, features, and advantages of the present application more clearly understandable.
Drawings
Fig. 1 is a schematic view of a reaction principle of the composite positive active material.
Fig. 2 is a schematic view of a secondary battery according to an embodiment of the present application.
Fig. 3 is an exploded view of the secondary battery according to the embodiment of the present application shown in fig. 2.
Fig. 4 is a schematic view of a battery module according to an embodiment of the present application.
Fig. 5 is a schematic view of a battery pack according to an embodiment of the present application.
Fig. 6 is an exploded view of the battery pack according to the embodiment of the present application shown in fig. 5.
Fig. 7 is a schematic diagram of an electric device in which the secondary battery according to the embodiment of the present application is used as a power source.
Description of the reference numerals:
1, a battery pack; 2, putting the box body on the box body; 3, discharging the box body; 4 a battery module; 5 a secondary battery; 51 a housing; 52 an electrode assembly; 53 a cap assembly.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are merely used to more clearly illustrate the technical solutions of the present application, and therefore are only examples, and the protection scope of the present application is not limited thereby.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures are intended to cover non-exclusive inclusions.
Reference herein to "one or more" means that at least one of the element is present; a plurality of such elements may be present unless specifically limited otherwise.
In the description of the present application, the term "and/or" is only one kind of association relation describing an associated object, and means that three kinds of relations may exist, for example, a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
The experimental procedures used in the following examples are all conventional procedures unless otherwise specified. Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.
At present, lithium iron manganese phosphate is a lithium ion secondary battery positive electrode active material with very wide market prospect, the raw material cost is low, the environment is friendly, but the problems of low conductivity, large polarization and low dynamic performance at low SOC exist for a long time, so that the cycle life and the rate capability of a battery cell are poor. Some improved technologies exist, for example, a composite material coated with ternary lithium manganese iron phosphate is used as a positive electrode active material, however, such technologies only coat a conductive layer on the lithium manganese iron phosphate, and the problems of large polarization of the lithium manganese iron phosphate and low dynamic performance at low SOC cannot be effectively solved.
In order to solve the problem of large polarization of lithium manganese iron phosphate, the applicant researches and discovers that the large polarization of the lithium manganese iron phosphate is caused by the fact that lithium ions and electrons are difficult to transmit due to the unique olivine structure of the lithium manganese iron phosphate, and therefore the problem can be solved by coating a material with good conductivity and small polarization on the surface of the lithium manganese iron phosphate.
The applicant also researches and discovers that lithium ion transmission of the lithium iron manganese phosphate battery is slow and the dynamic performance of the lithium iron manganese phosphate battery is poor under low SOC, so that the nano lithium iron phosphate with better dynamic performance under low SOC can be compounded on the surface of the lithium iron manganese phosphate battery.
Based on the above consideration, in order to solve the problems of low conductivity, large polarization, and low dynamic performance at low SOC at the same time, the inventors have conducted intensive studies and have designed a composite positive electrode active material, comprising: liMn x Fe 1-x PO 4 (0<x<1) A lithium ion conductor and a positive electrode active material with small polarization; the lithium ion conductor and the small-polarization positive active material are distributed in LiMn x Fe 1-x PO 4 (0<x<1) Of (2) is provided.
The battery prepared from the composite positive active material can be widely applied to various digital products, electric automobiles, energy storage base stations and the like.
According to some embodiments, in a first aspect, the present application provides a composite positive electrode active material, characterized by comprising: liMn x Fe 1-x PO 4 (0<x<1) A lithium ion conductor and a positive electrode active material having small polarization; the lithium ion conductor and the small-polarization positive active material are distributed in LiMn x Fe 1-x PO 4 (0<x<1) Of (2) is provided.
"polarization is small" means that the deviation from equilibrium potential is small when the cell has current flow.
Distribution in LiMn x Fe 1-x PO 4 (0<x<1) The surface of (a) "may be fully coated, partially coated, or partially chimeric.
The lithium ion conductor has strong conductivity, and the LiMn can be improved by leading the lithium ions to be strong x Fe 1-x PO 4 (0<x<1) The conductivity of (a); the positive electrode active material with small polarization can reduce LiMn x Fe 1-x PO 4 (0<x<1) The lithium ion conductor and the positive electrode active material with small polarization are distributed in the LiMn x Fe 1-x PO 4 (0<x<1) The surface energy of (2) improves the multiplying power performance of the battery core.
In some embodiments, the lithium ion conductor is polyethyleneimine PEI, polycaprolactone (C) 6 H 10 O 2 )n、Li 7 La 3 Zr 2 O 12 、Li 10 Ge(PS 6 ) 2 、Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 One or more combinations thereof.
These materials are well known lithium ion conductors, each of which has advantages and can be adapted for use in a variety of situations, either alone or in combination, to enhance conductivity.
In some embodiments, the small polarization positive active material is nano lithium iron phosphate, and/or nano LiNi x Co y Mn z O 2 (x+y+z＝1,0≤x≤0.6)。
Nano lithium iron phosphate and/or nano LiNi x Co y Mn z O 2 (x + y + z =1, 0. Ltoreq. X. Ltoreq.0.6) not only can reduce LiMn x Fe 1-x PO 4 (0<x<1) The polarization of the battery can be improved at the same time, and the dynamic performance of the battery at low SOC can be improved.
In some embodiments, liMn x Fe 1-x PO 4 (0<x<1) The molar ratio of the lithium ion conductor to the positive electrode active material having small polarization is 96 to 98:1-2:1-2.
The positive active material mixed according to the molar ratio range has higher rate performance and capacity retention rate.
In some embodiments, liMn x Fe 1-x PO 4 (0<x<1) Dv50 of (3): 7-13 μm, and the Dv50: 20-100nm of the positive electrode active material with small polarization.
LiMn x Fe 1-x PO 4 And Dv50 of a positive electrode active material with small polarizationWithin the range, the two can form better grain composition relation, and the particles can be fully contacted, thereby being beneficial to the transmission of lithium ions among the particles.
In a second aspect, the present application provides a positive electrode sheet, which is characterized by comprising the composite positive electrode active material.
In the composite positive electrode active material, the lithium ion conductor has strong conductivity and can improve LiMn x Fe 1-x PO 4 (0<x<1) The conductivity of (a); the positive electrode active material with small polarization can reduce LiMn x Fe 1-x PO 4 (0<x<1) Distribution of the lithium ion conductor and the positive electrode active material with small polarization in LiMn x Fe 1-x PO 4 (0<x<1) The positive pole piece prepared on the surface of the battery core can improve the multiplying power performance of the battery core.
In some embodiments, the cold pressed density of the positive electrode sheet: 3.45-3.5g/cm 3 。
The cold pressing density of the positive pole piece is moderate, so that the positive pole piece can be ensured to be in close contact with the positive active material particles, and has better wettability to the electrolyte.
In a third aspect, the application provides a method for preparing the positive electrode plate, which includes the steps of dissolving the composite positive electrode active material, the binder and the conductive carbon in the N-methylpyrrolidone, uniformly stirring, coating and cold pressing.
Since the lithium ion conductor has high conductivity, liMn can be increased x Fe 1-x PO 4 (0<x<1) The conductivity of (a); the positive electrode active material with small polarization can reduce LiMn x Fe 1-x PO 4 (0<x<1) Thus, a lithium ion conductor and a positive electrode active material having small polarization are distributed in LiMn x Fe 1-x PO 4 (0<x<1) The positive pole piece prepared by the composite positive active material formed on the surface can improve the multiplying power performance of the battery cell.
In some embodiments, the composite positive electrode active material comprises 96-97% by weight of the coated coating layer.
The composite anode active material is used as the main component of the coating and can effectively improve the LiMn x Fe 1-x PO 4 (0<x<1) And reduce its polarization.
In some embodiments, the pressure of cold pressing: 40-60T.
When the cold pressing pressure is within the range, the particles can be in close contact, so that the lithium ions can be transmitted among the particles, the internal resistance is reduced, the polarization loss is reduced, the cycle life of the battery is prolonged, and the utilization rate of the lithium ion secondary battery is improved.
In a fourth aspect, the present application provides a secondary battery, including the positive electrode sheet described above.
Since the lithium ion conductor has high conductivity, liMn can be increased x Fe 1-x PO 4 (0<x<1) The conductivity of (a); the positive active material with small polarization can reduce LiMn x Fe 1-x PO 4 (0<x<1) Thus, a secondary battery containing a lithium ion conductor and a positive active material having small polarization has high rate performance.
In a fifth aspect, the present application provides a battery module including the secondary battery described above.
Since batteries containing lithium ion conductors and a positive electrode active material with low polarization have high rate performance, battery modules composed of such secondary batteries have high rate performance.
In a sixth aspect, the present application provides a battery pack including the battery module described above.
A battery pack having a plurality of battery modules with high rate capability can rapidly transfer energy.
In a seventh aspect, the present application provides an electric device, including the above battery pack.
Because the battery pack with high rate capability is contained, the electric device can quickly obtain high-efficiency electric energy, timely respond and support other components to play functions, and the safety of the electric device in operation is guaranteed.
Referring to fig. 1, pei (lithium ion conductor) and nano lithium iron phosphate (small-polarization positive active material) are distributed on the surface of the lithium manganese iron phosphate.
The shape of the secondary battery is not particularly limited, and may be a cylindrical shape, a square shape, or any other arbitrary shape. For example, fig. 2 is a secondary battery 5 of a square structure as an example.
In some embodiments, referring to fig. 3, the overwrap may include a housing 51 and a cover plate 53. The housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose to form an accommodating cavity. The housing 51 has an opening communicating with the accommodating chamber, and a cover plate 53 can be provided to cover the opening to close the accommodating chamber. The positive electrode tab, the negative electrode tab, and the separator may be formed into the electrode assembly 52 through a winding process or a lamination process. An electrode assembly 52 is enclosed within the receiving cavity. The electrolyte is impregnated into the electrode assembly 52. The number of electrode assemblies 52 contained in the secondary battery 5 may be one or more, and those skilled in the art can select them according to the actual needs.
In some embodiments, the secondary batteries may be assembled into a battery module, and the number of the secondary batteries contained in the battery module may be one or more, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery module.
Fig. 4 is a battery module 4 as an example. Referring to fig. 4, in the battery module 4, a plurality of secondary batteries 5 may be arranged in series along the longitudinal direction of the battery module 4. Of course, the arrangement may be in any other way. The plurality of secondary batteries 5 may be further fixed by a fastener.
Alternatively, the battery module 4 may further include a case having an accommodation space in which the plurality of secondary batteries 5 are accommodated.
In some embodiments, the battery modules may be assembled into a battery pack, and the number of the battery modules contained in the battery pack may be one or more, and the specific number may be selected by one skilled in the art according to the application and the capacity of the battery pack.
Fig. 5 and 6 are a battery pack 1 as an example. Referring to fig. 5 and 6, a battery pack 1 may include a battery case and a plurality of battery modules 4 disposed in the battery case. The battery box comprises an upper box body 2 and a lower box body 3, wherein the upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4. A plurality of battery modules 4 may be arranged in any manner in the battery box.
In addition, this application still provides a power consumption device, power consumption device includes at least one in secondary battery, battery module or the battery package that this application provided. The secondary battery, the battery module, or the battery pack may be used as a power source of the electric device, and may also be used as an energy storage unit of the electric device. The powered device may include a mobile device (e.g., a mobile phone, a laptop computer, etc.), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship, a satellite, an energy storage system, etc., but is not limited thereto.
As the electricity-using device, a secondary battery, a battery module, or a battery pack may be selected according to the use requirement thereof.
Fig. 7 is an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle or a plug-in hybrid electric vehicle and the like. In order to meet the demand of the electric device for high power and high energy density of the secondary battery, a battery pack or a battery module may be used.
As another example, the device may be a cell phone, tablet, laptop, etc. The device is generally required to be thin and light, and a secondary battery may be used as a power source.
Comparative example 1
Mixing LiMn 0.7 Fe 0.3 PO 4 And the binder PVDF and the conductive agent Super P are dissolved in NMP according to the weight ratio of 96.2 0.7 Fe 0.3 PO 4 Dv50=8 μm, cold pressing pressure 45T, cold pressing density 3.5g/cm 3 。
Comparative example 2
Mixing LiMn 0.7 Fe 0.3 PO 4 Adding NMP, stirring for 10min, adding PEI, stirring for 2 hr, and adding PEIDrying to obtain LiMn 0.7 Fe 0.3 PO 4 Mixing PEI (molar ratio 98 0.7 Fe 0.3 PO 4 Dv50=8 μm, cold pressing pressure of 45T, cold pressing density of 3.5g/cm 3 。
Comparative example 3
Mixing LiMn 0.7 Fe 0.3 PO 4 Adding NMP, stirring for 10min, and adding nano LiFePO 4 Continuously stirring for 2h, and then drying to obtain LiMn 0.7 Fe 0.3 PO 4 Mixed nano LiFePO 4 (molar ratio 98 0.7 Fe 0.3 PO 4 Dv50=8 μm, nano-LiFePO 4 Dv50=80nm, cold pressing pressure 45T, cold pressing density 3.5g/cm 3 。
Example 1
Mixing LiMn 0.7 Fe 0.3 PO 4 Adding into NMP, stirring for 10min, adding PEI, stirring for 30min, adding nano LiFePO 4 Continuously stirring for 2 hours, and then drying to obtain LiMn 0.7 Fe 0.3 PO 4 Mixing PEI and nano LiFePO 4 (molar ratio 97 0.7 Fe 0.3 PO 4 Dv50=8 μm, nano-LiFePO 4 Dv50=80nm, cold pressing pressure 45T, cold pressing density 3.5g/cm 3 。
Example 2
Mixing LiMn 0.7 Fe 0.3 PO 4 Adding into NMPAdding PEI after stirring for 10min, adding nano LiFePO after stirring for 30min 4 Continuously stirring for 2h, and then drying to obtain LiMn 0.7 Fe 0.3 PO 4 Mixing PEI and nano LiFePO 4 (molar ratio 98 0.7 Fe 0.3 PO 4 Dv50=8 μm, nano-LiFePO 4 Dv50=80nm, cold pressing pressure 45T, cold pressing density 3.5g/cm 3 。
Example 3
Mixing LiMn 0.7 Fe 0.3 PO 4 Adding NMP, stirring for 10min, adding PEI, stirring for 30min, adding nano LiFePO 4 Continuously stirring for 2h, and then drying to obtain LiMn 0.7 Fe 0.3 PO 4 Mixing PEI and LiFePO 4 (molar ratio 97 0.7 Fe 0.3 PO 4 Dv50=8 μm, nano-LiFePO 4 Dv50=80nm, cold pressing pressure 45T, cold pressing density 3.5g/cm 3 。
Preparation of secondary battery
Mixing a positive electrode active material, a conductive agent acetylene black and a binder polyvinylidene fluoride (PVDF) according to a weight ratio of 96.2:1.1:2.7 fully stirring and uniformly mixing in an N-methyl pyrrolidone solvent system, coating on an aluminum foil, drying, and cold pressing to obtain the positive pole piece.
Artificial graphite serving as a negative electrode active material, acetylene black serving as a conductive agent, styrene Butadiene Rubber (SBR) serving as a binder and sodium carboxymethyl cellulose (CMC) serving as a thickening agent are mixed according to a weight ratio of 96.8:0.7:1.2:0.2:1.1, fully stirring and uniformly mixing in a deionized water solvent system, coating on a copper foil, drying and cold pressing to obtain the negative pole piece.
A porous polymer film made of Polyethylene (PE) was used as a separator.
And overlapping the positive plate, the isolating film and the negative plate in sequence to enable the isolating film to be positioned between the positive and negative electrodes to play an isolating role, and winding to obtain the bare cell. And placing the bare cell in an outer package, injecting electrolyte and packaging to obtain the secondary battery.
Cycle performance test of secondary battery
The secondary batteries prepared above are respectively circulated at 25 ℃ and 2.5-4.3V, charged to 4.3V by 16A constant current, constant voltage to 0.05C, left for 10min, discharged to 2.5V by 1Cn constant current, recorded with initial capacity as C0, and circularly charged and discharged until the capacity is Cn, and the Cn/C0 is less than or equal to 80 percent, and the test is stopped.
And (3) performance test results: see table 1.
TABLE 1
The results show LiMn alone compared to the composite material 0.7 Fe 0.3 PO 4 The rate performance and the capacity retention rate are relatively low; mixing PEI and nano LiFePO at the same time 4 Compared with the mixing of PEI only or nano LiFePO only 4 LiMn of (2) 0.7 Fe 0.3 PO 4 Higher in both rate capability and capacity retention. In summary, the composite of example 3 has the best rate capability and, correspondingly, the best dynamic performance.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present disclosure, and the present disclosure should be construed as being covered by the claims and the specification. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. The present application is not intended to be limited to the particular embodiments disclosed herein but is to cover all embodiments that may fall within the scope of the appended claims.
Claims (14)
1. A composite positive electrode active material, comprising: liMn x Fe 1-x PO 4 (0<x<1) A lithium ion conductor and a positive electrode active material having small polarization; the lithium ion conductor and the positive electrode active material with small polarization are distributed in LiMn x Fe 1-x PO 4 (0<x<1) Of (2) is provided.
2. The composite positive electrode active material according to claim 1, wherein the lithium ion conductor is polyethyleneimine PEI, polycaprolactone (C) 6 H 10 O 2 )n、Li 7 La 3 Zr 2 O 12 、Li 10 Ge(PS 6 ) 2 、Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 One or more combinations thereof.
3. The composite positive electrode active material according to claim 1 or claim 2, wherein the low-polarization positive electrode active material is nano lithium iron phosphate, and/or nano LiNi x Co y Mn z O 2 (x+y+z＝1,0≤x≤0.6)。
4. The composite positive electrode active material according to any one of claims 1 to 3, wherein the LiMn is x Fe 1-x PO 4 (0<x<1) The molar ratio of the lithium ion conductor to the small-polarization positive electrode active material is 96 to 98:1-2:1-2.
5. The composite positive electrode active material according to any one of claims 1 to 4, wherein the LiMn is x Fe 1-x PO 4 (0<x<1) Dv50 of (2) is 7-13 μm, the polarization is small positiveThe Dv50 of the polar active material is 20-100nm.
6. A positive electrode sheet comprising the composite positive electrode active material according to any one of claims 1 to 5.
7. The positive electrode sheet according to claim 6, wherein the cold pressing density of the positive electrode sheet is as follows: 3.45-3.5g/cm 3 。
8. A method for preparing the positive pole piece of claim 6 or 7, which comprises the steps of dissolving the composite positive pole active material, the binder and the conductive carbon of any one of claims 1 to 5 in N-methyl pyrrolidone, uniformly stirring, coating and cold pressing.
9. The method of claim 8, wherein the composite positive electrode active material comprises 96-97% by weight of the coated coating layer.
10. The method according to claim 8 or 9, wherein the pressure of the cold pressing is: 40-60T.
11. A secondary battery comprising the positive electrode sheet according to claim 6 or 7.
12. A battery module characterized by comprising the secondary battery according to claim 11.
13. A battery pack comprising the battery module according to claim 12.
14. An electric device comprising the battery pack according to claim 13.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111473505.6A CN115832283A (en) | 2021-11-29 | 2021-11-29 | Composite positive electrode active material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111473505.6A CN115832283A (en) | 2021-11-29 | 2021-11-29 | Composite positive electrode active material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115832283A true CN115832283A (en) | 2023-03-21 |
Family
ID=85516103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111473505.6A Pending CN115832283A (en) | 2021-11-29 | 2021-11-29 | Composite positive electrode active material |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115832283A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013069567A (en) * | 2011-09-22 | 2013-04-18 | Sumitomo Osaka Cement Co Ltd | Electrode active material and method for manufacturing the same, and lithium ion battery |
| JP2016146301A (en) * | 2015-02-09 | 2016-08-12 | 三井造船株式会社 | Positive electrode material for lithium secondary battery and manufacturing method of the same |
| CN107623112A (en) * | 2017-08-18 | 2018-01-23 | 宁波知能新材料有限公司 | Mix carbon coating lithium iron manganese phosphate anode material of lithium boron phosphate modification and preparation method thereof |
| CN108598386A (en) * | 2018-03-20 | 2018-09-28 | 深圳市德方纳米科技股份有限公司 | Iron manganese phosphate for lithium base composite positive pole and preparation method thereof |
| US20200161632A1 (en) * | 2017-05-29 | 2020-05-21 | Taiheiyo Cement Corporation | Positive electrode active material complex for lithium-ion secondary battery, secondary battery using same, and method for producing positive electrode active material complex for lithium-ion secondary battery |
-
2021
- 2021-11-29 CN CN202111473505.6A patent/CN115832283A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013069567A (en) * | 2011-09-22 | 2013-04-18 | Sumitomo Osaka Cement Co Ltd | Electrode active material and method for manufacturing the same, and lithium ion battery |
| JP2016146301A (en) * | 2015-02-09 | 2016-08-12 | 三井造船株式会社 | Positive electrode material for lithium secondary battery and manufacturing method of the same |
| US20200161632A1 (en) * | 2017-05-29 | 2020-05-21 | Taiheiyo Cement Corporation | Positive electrode active material complex for lithium-ion secondary battery, secondary battery using same, and method for producing positive electrode active material complex for lithium-ion secondary battery |
| CN107623112A (en) * | 2017-08-18 | 2018-01-23 | 宁波知能新材料有限公司 | Mix carbon coating lithium iron manganese phosphate anode material of lithium boron phosphate modification and preparation method thereof |
| CN108598386A (en) * | 2018-03-20 | 2018-09-28 | 深圳市德方纳米科技股份有限公司 | Iron manganese phosphate for lithium base composite positive pole and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111224158A (en) | Secondary battery, composite electrolyte, battery pack, and vehicle | |
| CN102427123A (en) | Lithium ion secondary battery and anode sheet thereof | |
| CN115133020A (en) | Lithium manganate positive electrode active material, positive electrode plate comprising same, secondary battery, battery module, battery pack and electric device | |
| CN115810796B (en) | Electrolyte, secondary battery comprising same and preparation method of secondary battery | |
| CN117637988A (en) | Negative electrode plate of high-energy-density battery, preparation method of negative electrode plate, battery and power utilization device | |
| US20230378613A1 (en) | Secondary battery, battery module, battery pack and power consuming device | |
| CN113113603A (en) | Lithium ion battery electrode plate, preparation method thereof and lithium ion battery | |
| CN115842118A (en) | Lithium salt composite material, negative plate, preparation method of negative plate, battery and electricity utilization device | |
| WO2023108352A1 (en) | Positive electrode active material and related electrode sheet, secondary battery, battery module, battery pack, and device | |
| CN116960287A (en) | Positive electrode material, preparation method thereof, composite positive electrode material, positive electrode plate and secondary battery | |
| CN117652039A (en) | Carbon nanotube and manufacturing method, application, secondary battery, battery module, battery pack and electricity utilization device thereof | |
| CN115832277A (en) | Positive electrode slurry, positive electrode piece, battery cell, battery monomer, battery and power utilization device | |
| CN115810863A (en) | Separator, method for producing same, secondary battery, battery module, battery pack, and electric device | |
| CN116130651A (en) | Pole piece, lithium ion battery, battery module, battery pack and electricity utilization device | |
| CN115832283A (en) | Composite positive electrode active material | |
| CN102956886A (en) | Lithium iron phosphate battery and preparation method thereof | |
| US20230124703A1 (en) | Negative electrode plate, secondary battery, battery module, battery pack and power consuming device | |
| WO2023141954A1 (en) | Lithium-ion battery, battery module, battery pack, and electric apparatus | |
| CN115842114B (en) | Positive electrode sheet, lithium ion secondary battery, battery module, battery pack, and power consumption device | |
| EP4258383A1 (en) | Positive electrode sheet, secondary battery, battery module, battery pack, electric device, and method for balancing internal voltage difference of battery | |
| EP4199146A1 (en) | Negative electrode sheet, secondary battery, battery module, battery pack, and electric device | |
| EP4228079A1 (en) | Battery pack and electric device therefor | |
| WO2024138385A1 (en) | Gel electrolyte composition, secondary battery, battery module, battery pack, and electrical device | |
| CN116435694A (en) | Battery pack and electricity utilization device | |
| CN116864837A (en) | Secondary battery and electricity utilization device |
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 |