CN115621554B - Electrolyte additive, electrolyte and lithium ion battery - Google Patents

Electrolyte additive, electrolyte and lithium ion battery Download PDF

Info

Publication number
CN115621554B
CN115621554B CN202211335720.4A CN202211335720A CN115621554B CN 115621554 B CN115621554 B CN 115621554B CN 202211335720 A CN202211335720 A CN 202211335720A CN 115621554 B CN115621554 B CN 115621554B
Authority
CN
China
Prior art keywords
lithium ion
battery
electrolyte
ion battery
formula
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
CN202211335720.4A
Other languages
Chinese (zh)
Other versions
CN115621554A (en
Inventor
李存璞
魏子栋
童成
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.)
Chongqing University Lithium Battery And New Materials Suining Research Institute
Original Assignee
Chongqing University Lithium Battery And New Materials Suining Research Institute
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 Chongqing University Lithium Battery And New Materials Suining Research Institute filed Critical Chongqing University Lithium Battery And New Materials Suining Research Institute
Priority to CN202211335720.4A priority Critical patent/CN115621554B/en
Publication of CN115621554A publication Critical patent/CN115621554A/en
Application granted granted Critical
Publication of CN115621554B publication Critical patent/CN115621554B/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
    • H01M10/056—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
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Secondary Cells (AREA)

Abstract

The invention discloses an electrolyte additive, electrolyte and a lithium ion battery, wherein the electrolyte additive comprises a compound shown in a formula (I). The electrolyte additive rapidly absorbs the heat accumulated locally by the battery through reversible molecular transformation of the compound shown in the formula (I) when the compound is heated, and slowly releases the absorbed heat when the battery is working normally, so that the safe working of the battery is ensured, and the problems of fire, explosion and the like caused by out-of-control heat in the battery are avoided. The lithium ion battery containing the electrolyte has better capacity retention rate, higher specific capacity of the positive electrode material, better polarization control, smaller battery polarization, slower increase of polarization voltage along with cyclic progress, more stable and uniform electrode interface of the battery, better puncture resistance performance during puncture experiments and better safety.

Description

Electrolyte additive, electrolyte and lithium ion battery
Technical Field
The invention belongs to the field of lithium ion batteries, and particularly relates to an electrolyte additive, electrolyte and a lithium ion battery.
Background
The development of human society is accompanied by the update of energy storage devices, and lithium ion batteries rapidly occupy the market of commercial energy storage devices due to the characteristics of high specific energy and low cost since the last century of business. With the continuous development of lithium ion batteries, the problem of safety in use of lithium ion batteries has attracted a great deal of attention, and the lithium ion batteries have the risk of spontaneous combustion in the process of charging and discharging, and the cause of spontaneous combustion can be summarized as follows: (1) Spontaneous combustion caused by the failure of a battery system, such as structural design defect of a battery pack, electrolyte leakage, explosion and the like caused by external impact; (2) The battery electrode interface is damaged due to overcharge and overdischarge of the battery, the electrode material reacts with electrolyte, and partial heat accumulation is caused by lithium precipitation to cause thermal runaway; (3) Thermal runaway caused by rapid discharge of the battery due to micro-short circuit inside the battery. In order to solve the problem of spontaneous combustion in the use process of the lithium ion battery, researchers start from a plurality of aspects and improve the problem of thermal runaway of the lithium ion battery, and mainly comprise the development of solid electrolyte, water-based electrolyte, a physical phase change cooling method and the like. However, the solid electrolyte and the water-based electrolyte in the method for solving the thermal runaway of lithium ions in the prior art are difficult to develop and face higher synthesis cost; the physical phase change rule cannot fundamentally solve the problem of thermal runaway; therefore, there is a need to develop a low-cost method that can intrinsically solve the thermal runaway of lithium ion batteries.
Disclosure of Invention
In order to overcome the problems of the prior art, it is an object of the present invention to provide an electrolyte additive.
The second purpose of the invention is to provide a preparation method of the electrolyte additive.
The third object of the present invention is to provide an electrolyte.
The fourth object of the invention is to provide a lithium ion battery.
The fifth object of the present invention is to provide an electrolyte additive or the use of an electrolyte in a battery.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
in a first aspect, the present invention provides an electrolyte additive comprising a compound of formula (I),
wherein A is selected from Li, na or K;
selected from->
Preferably, among the compounds represented by the formula (I),selected from-> Further preferably, in the compound represented by formula (I), the formula (I)>Selected from->
Preferably, in the compound represented by formula (I), a is selected from Li.
As shown in fig. 1, when the heat accumulation occurs locally in the battery, the compound shown in the formula (I) in the invention is subjected to chemical conversion (such as structural variation, ring opening, oxidation reduction and the like), and the compound shown in the formula (I) is converted from the low energy state alpha to the high energy state molecule gamma due to the existence of the energy potential well, so that a large amount of energy needs to be absorbed to overcome the energy potential well in the process, the chemical reaction occurs at the picosecond level, and the absorbed heat is tens of times of the phase-change heat, so that the heat generated locally in the battery can be rapidly absorbed and stored, and the normal operation of the battery electrode material interface is ensured. When the battery works at normal temperature, the molecules gamma and beta in the high-energy state can be mutually converted according to the thermodynamic principle, namely, the molecules gamma in the high-energy state are converted into the molecules beta, and the molecules beta can be slowly converted into the low-energy state alpha, so that the stored heat is slowly released, the rapid absorption and the slow release of the heat are realized, and the safe work of the lithium ion battery is ensured. The invention utilizes the compound shown in the formula (I) to absorb heat generated by the battery in order to overcome the energy potential well during the conversion process of the compound into different forms, thereby solving the problem of thermal runaway of the battery.
The compounds of formula (I) according to the invention are required to meet the following conditions: can be mutually dissolved with lithium ion battery electrolyte and does not react; the molecule can be driven by heat to quickly convert from a low energy state to a high energy state to absorb heat, and can be slowly and spontaneously converted from the high energy state to the low energy state and release energy at room temperature; the molecular conversion process is reversible, and no redundant product is produced or electrolyte is consumed.
A second aspect of the present invention is to provide a method for preparing the electrolyte additive provided in the first aspect of the present invention, the method comprising the steps of: mixing a compound shown in a formula (II) with diisopropylamino alkali metal for reaction to prepare the electrolyte additive,
wherein ,selected from->
Preferably, the alkali metal diisopropylamide is at least one of lithium diisopropylamide, sodium diisopropylamide or potassium diisopropylamide.
Preferably, the mixing reaction temperature is 20-40 ℃; further preferably, the mixing reaction temperature is 25 to 30 ℃.
Preferably, the mixing reaction time is 0.5-3 h; further preferably, the mixing reaction time is 0.5 to 2 hours.
Preferably, the mixing reaction is carried out under oxygen-free or low oxygen content; further preferably, the mixing reaction is carried out in a glove box.
Preferably, the preparation method further comprises the step of adding a solvent to perform a mixing reaction.
Preferably, the solvent is tetrahydrofuran.
Preferably, the mass ratio of the compound represented by the formula (II) to the diisopropylamino alkali metal substance is 1: (1-3); further preferably, the mass ratio of the compound represented by the formula (II) to the diisopropylamino alkali metal substance is 1: (2-3).
In a third aspect, the invention provides an electrolyte comprising the electrolyte additive provided in the first aspect of the invention.
Preferably, the electrolyte solution is further included in the electrolyte solution.
Preferably, the mass ratio of the electrolyte solution to the electrolyte additive is (10-1000): 1, a step of; further preferably, the mass ratio of the electrolyte solution to the electrolyte additive is (50 to 500): 1.
preferably, the electrolyte solution is an electrolyte solution used in a lithium ion battery or a lithium sulfur battery.
Preferably, the electrolyte solution includes an electrolyte and a solvent.
Preferably, the electrolyte is selected from LiPF 6 、LiTFSI、LiNO 3 At least one of them.
Preferably, the electrolyte is LiTFSI and LiNO 3 Or the electrolyte is LiPF 6 。
Preferably, the solvent is a mixture of DME and DOL, or the solvent is a mixture of EC, EMC and DMC.
Preferably, the preparation method of the electrolyte comprises the following steps: and mixing the electrolyte additive with an electrolyte solution to prepare the electrolyte.
Preferably, the mixing step employs at least one of stirring, ultrasound, and standing.
Preferably, the temperature of the mixing step is 20-40 ℃; further preferably, the temperature of the mixing step is 25-35 ℃; still more preferably, the temperature of the mixing step is 25 to 30 ℃.
Preferably, the time of the mixing step is 5-30 hours; further preferably, the mixing step is for a period of time ranging from 6 to 24 hours.
A fourth aspect of the invention provides a lithium ion battery comprising the electrolyte provided in the third aspect of the invention.
Preferably, the preparation method of the lithium ion battery comprises the steps of adding the electrolyte provided by the third aspect of the invention into the lithium ion battery, and then final sealing to prepare the lithium ion battery.
A fifth aspect of the invention provides the use of the electrolyte additive provided in the first aspect of the invention or the electrolyte provided in the third aspect of the invention in a battery.
Preferably, the battery is a lithium ion battery.
Preferably, the lithium ion battery comprises a lithium iron phosphate battery, a lithium cobalt oxide battery, a lithium manganate battery or a ternary lithium ion battery.
Preferably, the battery is a lithium ion pouch battery.
The beneficial effects of the invention are as follows: the electrolyte additive rapidly absorbs the heat accumulated locally by the battery through reversible molecular transformation of the compound shown in the formula (I) when the compound is heated, and slowly releases the absorbed heat when the battery is working normally, so that the safe working of the battery is ensured, and the problems of fire, explosion and the like caused by out-of-control heat in the battery are avoided.
The lithium ion battery containing the electrolyte has better capacity retention rate, higher specific capacity of the positive electrode material, better polarization control, smaller battery polarization, slower increase of polarization voltage along with cyclic progress, more stable and uniform electrode interface of the battery, better puncture resistance performance during puncture experiments and better safety.
Drawings
FIG. 1 shows the principle of the energy potential hydrazine of the compound of formula (I) according to the invention during different forms.
Fig. 2 is a cycle voltage test chart of the lithium ion soft pack battery in example 5 and comparative example 3.
Fig. 3 is a capacity retention test chart of lithium ion soft pack batteries in example 5 and comparative example 3.
Fig. 4 is a graph showing the polarization voltage of the lithium ion soft pack battery of example 6 and comparative example 4 as a function of the number of cycles.
Fig. 5 is a graph showing the change in coulombic efficiency with the number of cycles of the lithium ion pouch cells of example 7 and comparative example 5.
Fig. 6 is a graph showing the results of the needling experiments of the lithium ion pouch cells of example 8 and comparative example 6.
Detailed Description
Specific embodiments of the present invention will be described in further detail below with reference to the drawings and examples, but the practice and protection of the present invention are not limited thereto. It should be noted that the following processes, if not specifically described in detail, can be realized or understood by those skilled in the art with reference to the prior art. The reagents or apparatus used were not manufacturer-specific and were considered conventional products commercially available.
Example 1
The electrolyte for the lithium ion battery in the example consists of an additive and an electrolyte in a mass ratio of 1:50, wherein the electrolyte is LiPF with a concentration of 1mol/L 6 A solution; use in electrolyte for dissolving LiPF 6 The solvent of (a) is a mixed solvent of EC (ethylene carbonate), EMC (methyl ethyl carbonate) and DMC (dimethyl carbonate), and the volume ratio of EC, EMC and DMC is 1:1:1, wherein the additive is a compound shown in formula A and formula B, and the mass ratio is 1:1, wherein the structural formulae of formula a and formula B are as follows:
the electrolyte for the lithium ion battery in the example is prepared by adopting the following preparation method, and specifically comprises the following steps:
(1) Respectively measuring EC, EMC and DMC according to the volume ratio of 1:1:1, then mixing to obtain a mixed solvent, and mixing the LiPF 6 Adding into the mixed solvent to prepare LiPF with concentration of 1mol/L 6 A solution, i.e., an electrolyte;
(2) And respectively weighing the additive and the electrolyte according to the mass ratio of the additive to the electrolyte of 1:50, then mixing the additive and the electrolyte, and stirring for 24 hours at the temperature of 30 ℃ until the additive is completely dissolved and uniformly mixed to obtain the electrolyte for the lithium ion battery.
The preparation method of the additive in the example comprises the following steps:
the mass ratio is 1:1, cyclohepta-3-en-1-one (CAS No. 1121-64-8) and a compound represented by formula C (bicyclo [5.4.0] undec-6-en-2-one, CAS No. 1235804-17-7) were weighed respectively, then Lithium Diisopropylamide (LDA) was weighed in an amount twice as much as the total amount of cyclohepta-3-en-1-one and the compound represented by formula C, then all of the three substances were added to a tetrahydrofuran solution having a volume 10 times that of cyclohepta-3-en-1-one and the compound represented by formula C, stirred at a stirring speed of 100 rpm in a glove box at 20℃for sufficiently conducting an acid-base neutralization reaction for 1.5 hours, and then tetrahydrofuran was distilled off at 75℃to obtain the additive in this example.
Example 2
The electrolyte for the lithium ion battery in the example consists of an additive and the electrolyte in a mass ratio of 1:100. In the electrolyte, liNO 3 The mass percentage of the lithium bis (trifluoromethanesulfonyl imide) is 1 percent, the concentration of LiTFSI (lithium bis (trifluoromethanesulfonyl imide)) is 1mol/L, the solvent in the electrolyte is a mixed solvent of DME (ethylene glycol dimethyl ether) and DOL (1, 3-dioxolane), and the volume ratio of the DME to the DOL is 1:1. Wherein the additive is of formula A (same structure as formula A in example 1) andthe mass ratio of the compound shown in the formula D is 1:1, wherein formula D has the formula:
the electrolyte for the lithium ion battery in the example is prepared by adopting the following preparation method, and specifically comprises the following steps:
(1) Respectively measuring DME and DOL according to the volume ratio of 1:1, mixing to obtain a mixed solvent, adding LiTFSI into the mixed solvent to prepare LiTFSI solution with the concentration of 1mol/L, and then adding LiNO with the mass percentage of 1% into the LiTFSI solution 3 Is prepared into LiNO 3 And LiTFSI electrolyte;
(2) And respectively weighing the additive and the electrolyte according to the mass ratio of the additive to the electrolyte of 1:100, then mixing the additive and the electrolyte, and stirring for 8 hours at the temperature of 25 ℃ until the additive is completely dissolved and uniformly mixed to obtain the electrolyte for the lithium ion battery.
The preparation method of the additive in the example comprises the following steps:
the mass ratio is 1:1, cyclohepta-3-en-1-one (CAS No. 1121-64-8) and a compound represented by formula E (bicyclo [5.4.0] undec-4-en-2-one, CAS No. 136689-05-9) were weighed respectively, then Lithium Diisopropylamide (LDA) was weighed in three times the amount of the total substance of cyclohepta-3-en-1-one and the compound represented by formula E, then all of the three substances were added to a tetrahydrofuran solution having a volume 10 times the total volume of cyclohepta-3-en-1-one and the compound represented by formula E, stirred at a stirring speed of 100 rpm in a glove box at 20℃for 0.5 hours, and then tetrahydrofuran was distilled off at 75℃to obtain the additive in this example.
Example 3
In this example, the lithium ion battery is usedThe electrolyte of (2) consists of an additive and an electrolyte in a mass ratio of 1:500, wherein the electrolyte is LiPF with a concentration of 1mol/L 6 A solution; use in electrolyte for dissolving LiPF 6 The solvent of (a) is a mixed solvent of EC (ethylene carbonate), EMC (ethylmethyl carbonate) and DMC (dimethyl carbonate), and the volume ratio of EC, EMC and DMC is 1:1:1, wherein the additive is a compound shown as formula B (the structure of which is the same as that of formula B in example 1) and formula F, and the mass ratio is 1:1, wherein formula F has the following structural formula:
the electrolyte for the lithium ion battery in the example is prepared by adopting the following preparation method, and specifically comprises the following steps:
(1) Respectively measuring EC, EMC and DMC according to the volume ratio of 1:1:1, then mixing to obtain a mixed solvent, and mixing the LiPF 6 Adding into the mixed solvent to prepare LiPF with concentration of 1mol/L 6 A solution, i.e., an electrolyte;
(2) The additive and the electrolyte are respectively weighed according to the mass ratio of 1:500, then the additive and the electrolyte are mixed, and stirred for 8 hours at the temperature of 25 ℃ until the additive is completely dissolved and uniformly mixed, so that the electrolyte for the lithium ion battery in the embodiment is obtained.
The preparation method of the additive in the example comprises the following steps:
the mass ratio is 1:1, a compound represented by formula C and a compound represented by formula G (bicyclo [6.4.0] dodeca-1 (8) -en-9-one, CAS number 42186-21-0) were weighed separately, lithium Diisopropylamide (LDA) was weighed according to twice the total amount of the compound represented by formula C and the compound represented by formula G, and then all of the three substances were added to a tetrahydrofuran solution having a volume 10 times the total volume of the compound represented by formula C and the compound represented by formula G, stirred at a stirring speed of 100 rpm in a glove box at 20 ℃ for sufficiently conducting an acid-base neutralization reaction for 1.5 hours, and then tetrahydrofuran was distilled off at 75 ℃ to obtain an additive in this example.
Example 4
The electrolyte for the lithium ion battery in the example consists of an additive and an electrolyte in a mass ratio of 1:100, wherein the electrolyte is LiPF with a concentration of 1mol/L 6 A solution; use in electrolyte for dissolving LiPF 6 The solvent of (a) is a mixed solvent of EC (ethylene carbonate), EMC (ethylmethyl carbonate) and DMC (dimethyl carbonate), and the volume ratio of EC, EMC and DMC is 1:1:1, wherein the additive is a compound shown as formula D (the structure of the formula D is the same as that in the embodiment 2) and formula F, and the mass ratio is 1: 2.
The electrolyte for the lithium ion battery in the example is prepared by adopting the following preparation method, and specifically comprises the following steps:
(1) Respectively measuring EC, EMC and DMC according to the volume ratio of 1:1:1, then mixing to obtain a mixed solvent, and mixing the LiPF 6 Adding into the mixed solvent to prepare LiPF with concentration of 1mol/L 6 A solution, i.e., an electrolyte;
(2) And respectively weighing the additive and the electrolyte according to the mass ratio of the additive to the electrolyte of 1:100, then mixing the additive and the electrolyte, and stirring for 16 hours at the temperature of 25 ℃ until the additive is completely dissolved and uniformly mixed to obtain the electrolyte for the lithium ion battery.
The preparation method of the additive in the example comprises the following steps:
the mass ratio is 1:2 separately weighing the compound represented by formula E and the compound represented by formula G, then weighing Lithium Diisopropylamide (LDA) in twice the total amount of the compound represented by formula E and the compound represented by formula G, then adding the three substances into a tetrahydrofuran solution, wherein the volume of the tetrahydrofuran solution is 10 times of the total volume of the compound represented by formula E and the compound represented by formula G, stirring at a stirring speed of 100 revolutions per minute in a glove box at 20 ℃, sufficiently conducting acid-base neutralization reaction for 1.5 hours, and then distilling off tetrahydrofuran at 75 ℃ to obtain the additive in this example.
Example 5
The preparation method of the lithium ion soft package battery in the example comprises the following steps:
5mL of the electrolyte for the lithium ion battery in the embodiment 1 is added into a lithium iron phosphate battery containing 10 layers of positive electrode plates and 11 layers of negative electrode plates, then the soft package battery is subjected to final sealing, and the lithium ion soft package battery in the embodiment is obtained, and after the prepared lithium ion soft package battery is kept stand for a period of time, a charge and discharge test is carried out.
Example 6
The preparation method of the lithium ion soft package battery in the example comprises the following steps:
10mL of the electrolyte for the lithium ion battery in the example 2 is added into a lithium iron phosphate battery containing 10 layers of positive electrode plates and 11 layers of negative electrode plates, then the soft package battery is subjected to final sealing, and the lithium ion soft package battery in the example is obtained, and the prepared lithium ion soft package battery is subjected to charge and discharge test after being kept stand for a period of time.
Example 7
The preparation method of the lithium ion soft package battery in the example comprises the following steps:
10mL of the electrolyte for the lithium ion battery in the embodiment 3 is added into a lithium iron phosphate battery containing 10 layers of positive electrode plates and 11 layers of negative electrode plates, then the soft package battery is subjected to final sealing, the lithium ion soft package battery in the embodiment is obtained, and the prepared lithium ion soft package battery is subjected to charge and discharge test after being kept stand for a period of time.
Example 8
The preparation method of the lithium ion soft package battery in the example comprises the following steps:
5mL of the electrolyte for the lithium ion battery in the embodiment 4 is added into a nickel-cobalt-manganese (523) ternary lithium battery containing 4 layers of positive electrode plates and 5 layers of negative electrode plates, then the soft package battery is subjected to final sealing, so that the lithium ion soft package battery in the embodiment is obtained, and the prepared lithium ion soft package battery is subjected to charge and discharge tests after being kept stand for a period of time.
Comparative example 1
The electrolyte for the lithium ion battery in this example was LiPF with a concentration of 1mol/L 6 A solution; use in electrolyte for dissolving LiPF 6 Solvent of (2) is EC (ethyleneCarbonate), EMC (methyl ethyl carbonate) and DMC (dimethyl carbonate), and the volume ratio of EC, EMC and DMC is 1:1:1.
The electrolyte for the lithium ion battery in the example is prepared by adopting the following preparation method, and specifically comprises the following steps:
respectively measuring EC, EMC and DMC according to the volume ratio of 1:1:1, then mixing to obtain a mixed solvent, and mixing the LiPF 6 Adding into the mixed solvent to prepare LiPF with concentration of 1mol/L 6 The solution was stirred at 30℃for 24 hours to obtain an electrolyte for a lithium ion battery in this example.
Comparative example 2
In the electrolyte for lithium ion battery in this example, liNO 3 The mass percentage of the lithium bis (trifluoromethanesulfonyl imide) is 1 percent, the concentration of LiTFSI (lithium bis (trifluoromethanesulfonyl imide)) is 1mol/L, the solvent in the electrolyte is a mixed solvent of DME (ethylene glycol dimethyl ether) and DOL (1, 3-dioxolane), and the volume ratio of the DME to the DOL is 1:1.
The electrolyte for the lithium ion battery in the example is prepared by adopting the following preparation method, and specifically comprises the following steps:
respectively measuring DME and DOL according to the volume ratio of 1:1, mixing to obtain a mixed solvent, adding LiTFSI into the mixed solvent to prepare LiTFSI solution with the concentration of 1mol/L, and then adding LiNO with the mass percentage of 1% into the LiTFSI solution 3 Is prepared into LiNO 3 And LiTFSI, stirring for 8 hours at 25 ℃ to obtain the electrolyte for the lithium ion battery in the example.
Comparative example 3
The preparation method of the lithium ion soft package battery in the example comprises the following steps:
5mL of the electrolyte for the lithium ion battery in comparative example 1 was added to a lithium iron phosphate battery containing 10 layers of positive electrode sheets and 11 layers of negative electrode sheets, and then the soft-packed battery was subjected to final sealing to obtain a lithium ion soft-packed battery in this example, and the prepared lithium ion soft-packed battery was subjected to a charge and discharge test after standing for a period of time.
Comparative example 4
The preparation method of the lithium ion soft package battery in the example comprises the following steps:
10mL of the electrolyte for the lithium ion battery in comparative example 2 was added to a lithium iron phosphate battery containing 10 layers of positive electrode sheets and 11 layers of negative electrode sheets, and then the soft-packed battery was subjected to final sealing to obtain a lithium ion soft-packed battery in this example, and the prepared lithium ion soft-packed battery was subjected to a charge and discharge test after standing for a period of time.
Comparative example 5
The preparation method of the lithium ion soft package battery in the example comprises the following steps:
10mL of the electrolyte for the lithium ion battery in comparative example 1 was added to a lithium iron phosphate battery containing 10 layers of positive electrode pieces and 11 layers of negative electrode pieces, and then the soft-packed battery was subjected to final sealing to obtain a lithium ion soft-packed battery in this example, and the prepared lithium ion soft-packed battery was subjected to a charge and discharge test after standing for a period of time.
The lithium ion battery packs of comparative examples 3 to 5 were identical to those of examples 5 to 7 in terms of materials and conditions except for the electrolyte.
Comparative example 6
The preparation method of the lithium ion soft package battery in the example comprises the following steps:
5mL of the electrolyte for the lithium ion battery in comparative example 1 is added into a nickel-cobalt-manganese (523) ternary lithium battery containing 4 layers of positive electrode pieces and 5 layers of negative electrode pieces, then the soft package battery is subjected to final sealing, so as to obtain the lithium ion soft package battery in the example, and the prepared lithium ion soft package battery is subjected to a charge and discharge test after being kept stand for a period of time.
The lithium ion battery pack in comparative example 6 was identical to the lithium ion battery pack in example 8 in terms of materials and conditions except for the electrolyte.
The mass of the positive electrode active material of the entire lithium ion pouch cells in examples 5 to 8 and comparative examples 3 to 6 was 6.42g.
Performance testing
The lithium ion pouch cells in example 5 and comparative example 3 were tested for cycling voltage and capacity retention, respectively, under the following test conditions: the soft package battery is subjected to charge and discharge test in a voltage interval of 2.6-3.7V under the charge and discharge multiplying power of 0.2C, the test results are respectively shown in fig. 2 and 3, wherein fig. 2 (a) and 2 (B) are respectively cyclic voltage diagrams of the lithium ion soft package battery in comparative example 3 and example 5, curve A, curve B, curve C, curve D and curve E in fig. 2 (a) are respectively cyclic voltage diagrams of the lithium ion soft package battery in comparative example 3 after 1 circle, 10 circles, 20 circles, 50 circles and 80 circles of the lithium ion soft package battery under the multiplying power of 0.2C, and the same letter marks on the curves in fig. 2 (a) represent the same curve; curve a, curve B, curve C, curve D and curve E in fig. 2 (B) are cyclic voltage diagrams after the lithium ion pouch cell in example 5 circulates 1 cycle, 10 cycles, 20 cycles, 50 cycles and 80 cycles at a 0.2C magnification, respectively, and the same letter marks on the curves in fig. 2 (B) represent the same curve; fig. 3 is a capacity retention test chart of lithium ion soft pack batteries in example 5 and comparative example 3. As can be seen from fig. 2 and 3, the lithium ion pouch battery of example 5, which has an additive introduced into the electrolyte, has a more stable capacity retention rate after 0.2C rate cycle, compared with comparative example 3, because the compounds of formula a and formula B in the additive absorb local heat accumulation, thereby ensuring uniformity of a lithium ion pouch battery reaction interface and stability of an SEI film, and thus an electrode reaction can be more sufficiently and reversibly performed.
The polarization voltage is the voltage difference between the charge and discharge platforms in the process of circularly charging and discharging the battery in the soft package battery test system, and is the data read from the charge and discharge curves of different circle numbers after the battery cycle test is finished, and the results of the change of the polarization voltage of the lithium ion soft package battery in the example 6 and the comparative example 4 along with the circle number are shown in fig. 4. As can be seen from fig. 4, the lithium ion pouch cell of example 6 of the present invention, which incorporated the additive, has a smaller initial polarization voltage under 0.2C rate charge and discharge conditions than comparative example 4. The increase of the polarization voltage of the lithium ion soft-pack battery in the embodiment 6 is slower along with the increase of the number of charge and discharge cycles, which indicates that the addition of the compound shown in the molecular formula A and the formula D of the energy potential well can effectively relieve the polarization of the electrode-electrolyte interface in the circulation process of the lithium ion soft-pack battery, improve the circulation stability and the safety of the battery, and further indicates that the invention can effectively eliminate the accumulation of uneven heat in the battery, improve the electrode reaction interface, ensure the uniformity of the interface and improve the safety and the circulation stability of the battery by introducing the energy potential well molecule as an additive to the electrolyte.
The coulombic efficiency is recorded in real time during the cyclic charge and discharge process of the battery by the soft package battery test system, wherein the change results of the coulombic efficiency of the lithium ion soft package battery in the embodiment 7 and the comparative example 5 along with the cycle number are shown in fig. 5, and as can be known from fig. 5, the coulombic efficiency of the embodiment 7 applying the additive of the invention is constantly lower than that of the comparative example 5, because the additive molecule can store energy during the charging process, the conversion of the molecular configuration is realized, the energy which is locally nonuniform is absorbed, thereby improving the interface uniformity during the charging process, and realizing constant energy storage.
The lithium ion pouch cells of example 8 and comparative example 6 were subjected to a needling experiment, respectively, under the following test conditions: the diameter of the puncture needle is 3mm, the needling speed is 100mm/s, the taper angle of the needle tip is 60 degrees, the experimental temperature is 25 ℃, and the soft package battery is placed in the incubator during testing. The test results are shown in fig. 6, wherein fig. 6 (a) and 6 (b) are graphs showing the results of the needling experiments of the lithium ion battery packs of example 8 and comparative example 6, respectively; as can be seen from fig. 6, compared with comparative example 6, the lithium ion battery pack of example 8 has higher puncture resistance, no ignition combustion and higher safety when the needling experiment is performed due to the introduction of the compounds of the energy potential well formula D and formula F, whereas the lithium ion battery pack of comparative example 6 has extremely low safety due to the ignition immediately after the needling.
While the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes may be made without departing from the spirit of the present invention within the knowledge of those skilled in the art. Furthermore, embodiments of the invention and features of the embodiments may be combined with each other without conflict.

Claims (8)

1. An electrolyte additive for a lithium ion battery is characterized in that: comprising a compound shown in a formula (I),
wherein A is Li;
selected from->
2. The lithium ion battery electrolyte additive according to claim 1, wherein: of the compounds represented by the formula (I),
selected from->
3. The lithium ion battery electrolyte additive according to claim 2, characterized in that: of the compounds represented by the formula (I),
selected from->
4. A method for preparing the lithium ion battery electrolyte additive according to any one of claims 1 to 3, characterized in that: the method comprises the following steps: mixing a compound shown in a formula (II) with diisopropylamino alkali metal for reaction to prepare the lithium ion battery electrolyte additive,
wherein ,selected from->
5. The method for preparing the lithium ion battery electrolyte additive according to claim 4, wherein: the diisopropylamino alkali metal is at least one of lithium diisopropylamino, sodium diisopropylamino or potassium diisopropylamino.
6. The lithium ion battery electrolyte is characterized in that: comprising the lithium ion battery electrolyte additive and the electrolyte solution according to any one of claims 1 to 3, wherein the mass ratio of the electrolyte solution to the lithium ion battery electrolyte additive is (10 to 1000): 1.
7. a lithium ion battery, characterized in that: comprising the lithium ion battery electrolyte of claim 6.
8. Use of the lithium ion battery electrolyte additive of any one of claims 1 to 3 or the lithium ion battery electrolyte of claim 6 in a lithium ion battery.
CN202211335720.4A 2022-10-28 2022-10-28 Electrolyte additive, electrolyte and lithium ion battery Active CN115621554B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211335720.4A CN115621554B (en) 2022-10-28 2022-10-28 Electrolyte additive, electrolyte and lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211335720.4A CN115621554B (en) 2022-10-28 2022-10-28 Electrolyte additive, electrolyte and lithium ion battery

Publications (2)

Publication Number Publication Date
CN115621554A CN115621554A (en) 2023-01-17
CN115621554B true CN115621554B (en) 2023-08-22

Family

ID=84876102

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211335720.4A Active CN115621554B (en) 2022-10-28 2022-10-28 Electrolyte additive, electrolyte and lithium ion battery

Country Status (1)

Country Link
CN (1) CN115621554B (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110212164A (en) * 2019-06-10 2019-09-06 珠海冠宇电池有限公司 A method of lithium ion battery energy density is improved using lithium salts
CN113224386A (en) * 2021-04-30 2021-08-06 松山湖材料实验室 Cobalt acid lithium battery electrolyte additive, electrolyte and battery thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220131125A1 (en) * 2020-10-22 2022-04-28 Sila Nanotechnologies Inc. Surface coated porous substrates and particles and systems and methods thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110212164A (en) * 2019-06-10 2019-09-06 珠海冠宇电池有限公司 A method of lithium ion battery energy density is improved using lithium salts
CN113224386A (en) * 2021-04-30 2021-08-06 松山湖材料实验室 Cobalt acid lithium battery electrolyte additive, electrolyte and battery thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Separators Based on the Dynamic Tip-Occupying Electrostatic Shield Effect for Dendrite-Free Lithium-Metal Batteries;Qin Tong 等;《advanced sustainble systems》;第6卷;2100386中的第1-9页 *

Also Published As

Publication number Publication date
CN115621554A (en) 2023-01-17

Similar Documents

Publication Publication Date Title
Wu et al. Comparison analysis on the thermal runaway of lithium-ion battery under two heating modes
Jiang et al. Electrochemical performance and thermal stability analysis of LiNixCoyMnzO2 cathode based on a composite safety electrolyte
CN105264692B (en) Novel electrolytes composition for high energy anode
CN101640288B (en) Lithium-ion battery electrolyte and lithium-ion battery containing same
US20240097124A1 (en) Positive active material, positive electrode plate and lithium-ion secondary battery
CN104600363B (en) Electrolyte for preventing spinel lithium titanate-based lithium ion secondary battery from flatulence
CN113363581B (en) Non-aqueous electrolyte and secondary battery thereof
CN107331893A (en) A kind of high-temperature lithium-ion battery electrolyte and preparation method thereof and high temperature lithium ion battery
CN101662046A (en) Lithium ion battery
CN115810799A (en) High-performance lithium metal battery electrolyte and high-performance lithium metal battery
KR20240019835A (en) Lithium-ion batteries, battery modules, battery packs and electrical devices
CN102651486B (en) Lithium ion battery redox couple additive and lithium ion battery electrolyte
US20070031734A1 (en) Electrolyte additives for lithium metal and lithium ion rechargeable batteries
CN115621554B (en) Electrolyte additive, electrolyte and lithium ion battery
Uyama et al. Realizing the ultimate thermal stability of a lithium-ion battery using two zero-strain insertion materials
CN116799153A (en) Method for preparing anode material by coating and modifying metal sulfide
CN104466174A (en) Cathode active substance for lithium ion battery and preparation method thereof
CN113889667B (en) High-voltage electrolyte adaptive to lithium cobaltate battery capable of being charged quickly and application of high-voltage electrolyte
WO2022266886A1 (en) Preparation method for sei membrane-like component additive, electrolyte, lithium ion battery, battery module, battery pack, and electric device
CN103311546A (en) Electrode piece of lithium ion battery and lithium ion battery
CN108539273A (en) A kind of novel lithium secondary cell electrolyte and a kind of lithium secondary battery
CN114156533B (en) Lithium ion battery gel electrolyte and preparation method of lithium ion battery
CN112047398B (en) K 2 Ni 2 (MoO 4 ) 3 Application in lithium ion battery cathode
Wang et al. Improved thermal stability of graphite electrodes in lithium-ion batteries using 4-isopropyl phenyl diphenyl phosphate as an additive
CN112186246B (en) Lithium salt electrolyte additive, electrolyte containing additive 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