CN112825373B - Non-aqueous electrolyte and lithium secondary battery comprising same - Google Patents
Non-aqueous electrolyte and lithium secondary battery comprising same Download PDFInfo
- Publication number
- CN112825373B CN112825373B CN201911144466.8A CN201911144466A CN112825373B CN 112825373 B CN112825373 B CN 112825373B CN 201911144466 A CN201911144466 A CN 201911144466A CN 112825373 B CN112825373 B CN 112825373B
- Authority
- CN
- China
- Prior art keywords
- secondary battery
- lithium
- lithium secondary
- additive
- hexanetricarbonitrile
- 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
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic 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
Abstract
The invention provides a non-aqueous electrolyte and a lithium secondary battery comprising the same, wherein the non-aqueous electrolyte comprises an organic solvent, an additive and a lithium salt, and the additive at least contains a polynary nitrile compound; the dosage of the additive accounts for 0.01 to 10 weight percent of the total weight of the nonaqueous electrolyte; the polynary nitrile compound is prepared from low-element nitrile compounds, and the content of the low-element nitrile compounds in the polynary nitrile compounds is 5-60 ppm. The electrolyte with better high-temperature cycle performance is prepared by controlling the content of raw material impurities in the polynary nitrile compound serving as the additive and the using amount of the additive, and the high-temperature cycle performance of the electrolyte is obviously improved when the electrolyte is used for a lithium secondary battery.
Description
Technical Field
The invention belongs to the technical field of electrolyte, and particularly relates to a non-aqueous electrolyte and a lithium secondary battery comprising the same.
Background
Compared with lead-acid batteries, cadmium-nickel batteries and nickel-hydrogen batteries, the lithium secondary battery has the advantages of high working voltage, high specific energy, small self-discharge, long cycle life, no memory effect and the like, so that the lithium secondary battery is developed rapidly in recent years, and the performance index is improved continuously. As the demand for the endurance of the lithium secondary battery increases, developers have to further increase the charging voltage of the lithium secondary battery. However, this deteriorates the cycle performance of the lithium secondary battery.
The electrolyte additive has the outstanding advantage of being most economical and feasible for improving the performance of the lithium secondary battery. The polynary nitrile compound is a common additive for improving high-temperature cycle performance, and the high-temperature cycle performance of the lithium secondary battery can be obviously improved by adding a small amount of polynary nitrile compound into the electrolyte, so that the lithium secondary battery which is suitable for high voltage and has better high-temperature cycle performance is prepared.
However, even when a polynitrile compound is added, the lithium secondary battery produced has a problem that the transition metal ions are eluted at a high voltage and the high-temperature performance is poor, and thus it is difficult to achieve an optimum state.
Disclosure of Invention
The invention aims to solve the problems of the existing lithium secondary battery that the transition metal ions are dissolved out under high voltage and the high-temperature performance is poor, and provides a non-aqueous electrolyte and a lithium secondary battery containing the non-aqueous electrolyte.
When the polynary nitrile compound is produced from a monovalent nitrile compound or a lower nitrile compound, the monovalent nitrile compound or the lower nitrile compound is generally contained as an impurity because it is difficult to completely remove the compound by a simple purification method. Taking 1,3, 6-hexanetricarbonitrile as an example, it is prepared from acrylonitrile, and generally contains a trace amount of acrylonitrile impurities, and even purified 1,3, 6-hexanetricarbonitrile inevitably contains residual acrylonitrile. The inventors have studied and found that when the polynitrile compound is used as an additive for an electrolyte, the content of raw material impurities (such as acrylonitrile) therein greatly affects the performance of a lithium secondary battery, and as a result, it has been found that the raw material impurities generally contain cyano-conjugated double bonds which are superior to the action of the polynitrile compound on a positive electrode to stabilize a transition metal on the surface by complexing with transition metal ions on the surface at the positive electrode because the polynitrile compound reacts at the positive electrode at the time of first charging of the lithium secondary battery. The inventor of the present application finds, through research, that an electrolyte having a better high-temperature cycle performance can be prepared by controlling the content of raw material impurities in the polynitrile compound. Specifically, when the content of raw material impurities is controlled within the range of 5-60ppm, the raw material impurities can be completely reduced at the negative electrode during the first charging, and the reaction at the positive electrode is not carried out any more, so that the effect of polynitrile compounds on the positive electrode protection is not influenced; in addition, the reduced raw material impurities can form a good interface film on the surface of the negative electrode, and nitrile groups (-CN) in the raw material impurities can be combined with transition metal on the surface of the negative electrode, so that the deposition of transition metal ions dissolved out from the positive electrode on the negative electrode is inhibited, and the decomposition of electrolyte on the negative electrode is inhibited; based on this, the high-temperature cycle performance of the lithium secondary battery is remarkably improved, and the purpose of the invention is achieved.
The purpose of the invention is realized by the following technical scheme:
a nonaqueous electrolytic solution comprising an organic solvent, an additive and a lithium salt, wherein the additive contains at least a polynitrile compound; the dosage of the additive accounts for 0.01 to 10 weight percent of the total weight of the nonaqueous electrolyte; the polynary nitrile compound is prepared from low-element nitrile compounds, and the content of the low-element nitrile compounds in the polynary nitrile compounds is 5-60 ppm.
Wherein the low-membered nitrile compound is selected from compounds having a structure represented by formula (1):
in the formula (1), R1And R2Identical or different, independently of one another, from H, halogen, alkyl or aryl; r3Selected from H, halogen, alkyl or aryl; when R is1And R3When selected from hydrocarbon groups, they may be linked to each other to form a ring, i.e., a compound having a structure represented by the following formula (2):
in the formula (2), R2Is as defined in formula (1); r'1And R'3Are each R1And R3By removal of one H group, R1And R3Identical or different, independently of one another, from the group of hydrocarbon radicals.
The non-aqueous electrolyte comprises an organic solvent, an additive and a lithium salt, wherein the additive at least contains 1,3, 6-hexanetrinitrile; the dosage of the additive accounts for 0.01 to 10 weight percent of the total weight of the nonaqueous electrolyte; the content of acrylonitrile in the 1,3, 6-hexanetricarbonitrile is 5-60 ppm.
Wherein the 1,3, 6-hexanetricarbonitrile has an acrylonitrile content of 5 to 58ppm, such as 7 to 55ppm, such as 8 to 53ppm, such as 8.99 to 51.99ppm, such as 9.99 to 31.99 ppm.
Wherein the additive is used in an amount of 0.1 to 5wt%, for example, 0.5 to 2wt%, based on the total weight of the nonaqueous electrolytic solution.
Wherein the organic solvent is at least one selected from carbonate (such as cyclic carbonate and chain carbonate), carboxylate (such as cyclic carboxylate and chain carboxylate), ether compound (such as cyclic ether compound and chain ether compound), phosphorus-containing compound, sulfur-containing compound and aromatic fluorine-containing compound.
The lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis (fluorosulfonyl) imide, lithium difluoro oxalate borate, lithium bis (trifluoromethanesulfonyl) imide, lithium bis (oxalato) borate and lithium difluoro oxalate phosphate, and accounts for 8-25wt% of the total mass of the nonaqueous electrolyte.
The invention also provides a lithium secondary battery which comprises the nonaqueous electrolyte.
The lithium secondary battery further comprises a positive plate, a negative plate and a diaphragm, wherein the diaphragm is arranged between the positive plate and the negative plate.
Wherein the specific surface area of the positive active material in the positive plate is 0.1-1 m2The specific surface area of the negative active material in the negative plate is 1-2 m2/g。
The invention has the beneficial effects that:
the invention provides a non-aqueous electrolyte and a lithium secondary battery containing the same, wherein the electrolyte has better high-temperature cycle performance and can improve the charging performance of the lithium secondary battery.
The electrolyte with better high-temperature cycle performance can be prepared by controlling the content of raw material impurities in the polynitrile compound. Specifically, when the content of raw material impurities is controlled within the range of 5-60ppm, the raw material impurities can be completely reduced at the negative electrode during the first charging, and the reaction at the positive electrode is not carried out any more, so that the effect of polynitrile compounds on the positive electrode protection is not influenced; in addition, the reduced raw material impurities can form a good interface film on the surface of the negative electrode, and nitrile groups (-CN) in the raw material impurities can be combined with transition metal on the surface of the negative electrode, so that the deposition of transition metal ions dissolved out from the positive electrode on the negative electrode is inhibited, and the decomposition of electrolyte on the negative electrode is inhibited; based on this, the high-temperature cycle performance of the lithium secondary battery is significantly improved.
Drawings
Fig. 1 is a graph of cycle performance for example 1, comparative example 2, and comparative example 3.
Detailed Description
As described above, the present invention provides a nonaqueous electrolytic solution including an organic solvent, an additive, and a lithium salt, wherein the additive contains at least a polynitrile compound; the dosage of the additive accounts for 0.01 to 10 weight percent of the total weight of the nonaqueous electrolyte; the polynary nitrile compound is prepared from low-element nitrile compounds, and the content of the low-element nitrile compounds in the polynary nitrile compounds is 5-60 ppm.
In the present invention, the low-membered nitrile compound means a nitrile compound in which the number of cyano CNs is smaller than that of the above-mentioned polybasic nitrile compound; for example, if the polynary nitrile compound is a ternary nitrile compound, the lower nitrile compound is a monovalent nitrile compound or a divalent nitrile compound.
Wherein the low-membered nitrile compound may be selected from compounds having a structure represented by formula (1):
in the formula (1), R1And R2Identical or different, independently of one another, from H, halogen, hydrocarbon or aromaticA group; r3Selected from H, halogen, alkyl or aryl; when R is1And R3When selected from hydrocarbon groups, they may be linked to each other to form a ring, i.e., a compound having a structure represented by the following formula (2):
in the formula (2), R2Is as defined in formula (1); r'1And R'3Are each R1And R3By removal of one H group, R1And R3Identical or different, independently of one another, from the group of hydrocarbon radicals.
Preferably, R1And R2Identical or different, independently of one another, from H, halogen, alkyl; r3Selected from H, halogen, alkyl; when R is1And R3When selected from alkyl groups, they may be linked to each other to form a ring. Specifically, the R is1、R2、R3Is selected from H.
Wherein the polynary nitrile compound is prepared from low-element nitrile compounds, and the low-element nitrile compounds at least comprise the compound with the structure shown in the formula (1). For example, when the lower nitrile is selected from acrylonitrile, the higher nitrile is selected from 1,3, 6-hexanetricarbonitrile.
The "halogen" in the invention refers to fluorine, chlorine, bromine or iodine.
"hydrocarbyl" as used herein alone or as suffix or prefix, is for example a straight or branched chain saturated/unsaturated aliphatic radical, which may in particular be an alkyl, alkenyl or alkynyl radical.
"alkyl" used herein alone or as suffix or prefix, is intended to include both branched and straight chain saturated aliphatic hydrocarbon groups having from 1 to 20, preferably from 1 to 6, carbon atoms. For example, "C1-6 alkyl" denotes straight and branched chain alkyl groups having 1,2, 3, 4, 5 or 6 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, and hexyl.
"alkenyl" as used herein alone or as a suffix or prefix, is intended to include both branched and straight chain aliphatic hydrocarbon radicals containing alkenyl or alkene radicals having from 2 to 20, preferably 2-6, carbon atoms (or the particular number of carbon atoms if provided). For example, "C2-6 alkenyl" denotes alkenyl having 2,3, 4, 5 or 6 carbon atoms. Examples of alkenyl groups include, but are not limited to, vinyl, allyl, 1-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methylbut-2-enyl, 3-methylbut-1-enyl, 1-pentenyl, 3-pentenyl, and 4-hexenyl.
"alkynyl" used herein alone or as a suffix or prefix is intended to include both branched and straight chain aliphatic hydrocarbon radicals containing alkynyl groups or alkynes having 2 to 20, preferably 2-6 carbon atoms (or the particular number of carbon atoms if provided). For example ethynyl, propynyl (e.g., l-propynyl, 2-propynyl), 3-butynyl, pentynyl, hexynyl and 1-methylpent-2-ynyl.
"aryl" used herein alone or as a suffix or prefix, refers to an aromatic ring structure made up of 5 to 20 carbon atoms. For example: the aromatic ring structure containing 5, 6, 7 and 8 carbon atoms may be a monocyclic aromatic group such as phenyl; the ring structure containing 8, 9, 10, 11, 12, 13 or 14 carbon atoms may be polycyclic, for example naphthyl. The aromatic ring may be substituted at one or more ring positions with substituents such as alkyl, halogen, and the like, e.g., tolyl. The term "aryl" also includes polycyclic ring systems having two or more cyclic rings in which two or more carbons are common to two adjoining rings (the rings are "fused rings"), wherein at least one of the rings is aromatic and the other cyclic rings can be, for example, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, and/or heterocyclyl. Examples of polycyclic rings include, but are not limited to, 2, 3-dihydro-1, 4-benzodioxine and 2, 3-dihydro-1-benzofuran.
In a specific embodiment, the nonaqueous electrolytic solution comprises an organic solvent, an additive and a lithium salt, wherein the additive at least contains 1,3, 6-hexanetricarbonitrile; the dosage of the additive accounts for 0.01 to 10 weight percent of the total weight of the nonaqueous electrolyte; the content of acrylonitrile in the 1,3, 6-hexanetricarbonitrile is 5-60 ppm.
In one embodiment of the invention, the 1,3, 6-hexanetricarbonitrile has an acrylonitrile content of from 5 to 58ppm, for example from 7 to 55ppm, for example from 8 to 53ppm, for example from 8.99 to 51.99ppm, for example from 9.99 to 31.99 ppm.
In one embodiment of the present invention, the 1,3, 6-hexanetricarbonitrile is used in an electrolyte solution, and can form a film on a positive electrode and inhibit elution of metal ions from the positive electrode. When the content of acrylonitrile in 1,3, 6-hexanetricarbonitrile is controlled to be within a range of 5-60ppm, acrylonitrile can be completely reduced at the negative electrode during first charging, and the effect of 1,3, 6-hexanetricarbonitrile on the positive electrode protection will not be affected.
As above, the additive is used in an amount of 0.01 to 10wt% based on the total weight of the nonaqueous electrolytic solution; in one embodiment of the present invention, the amount is 0.1 to 5wt%, and further, for example, 0.5 to 2wt% based on the total weight of the nonaqueous electrolytic solution.
In one embodiment of the present invention, the organic solvent is at least one selected from the group consisting of a carbonate (e.g., cyclic carbonate, chain carbonate), a carboxylate (e.g., cyclic carboxylate, chain carboxylate), an ether compound (e.g., cyclic ether compound, chain ether compound), a phosphorus-containing compound, a sulfur-containing compound, and an aromatic fluorine-containing compound.
Wherein the carbonate is at least one selected from the group consisting of dimethyl carbonate, methylethyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate, di-n-propyl carbonate, bis (fluoromethyl) carbonate, bis (difluoromethyl) carbonate, bis (trifluoromethyl) carbonate, bis (2-fluoroethyl) carbonate, bis (2, 2-difluoroethyl) carbonate, bis (2,2, 2-trifluoroethyl) carbonate, 2-fluoroethyl methyl carbonate, 2, 2-difluoroethyl methyl carbonate and 2,2, 2-trifluoroethyl methyl carbonate.
Wherein the carboxylic acid ester is selected from at least one of methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, sec-butyl acetate, isobutyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, methyl isobutyrate, ethyl isobutyrate, methyl valerate, ethyl valerate, methyl pivalate and ethyl pivalate, methyl trifluoroacetate, ethyl trifluoroacetate, propyl trifluoroacetate, butyl trifluoroacetate, trifluoroacetic acid and 2,2, 2-trifluoroethyl ester.
Wherein the ether compound is at least one selected from tetrahydrofuran, 2-methyltetrahydrofuran, 1, 3-dioxolane, 2-methyl-1, 3-dioxolane, 4-methyl-1, 3-dioxolane, 1, 3-dioxane, 1, 4-dioxane, dimethoxypropane, dimethoxymethane, 1-dimethoxyethane, 1, 2-dimethoxyethane, diethoxymethane, 1-diethoxyethane, 1, 2-diethoxyethane, ethoxymethoxymethane, 1-ethoxymethoxyethane and 1, 2-ethoxymethoxyethane.
Wherein the phosphorus-containing compound is selected from at least one of trimethyl phosphate, triethyl phosphate, dimethyl ethyl phosphate, methyl diethyl phosphate, ethylene methyl phosphate, ethylene ethyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, tris (2,2, 2-trifluoroethyl) phosphate, and tris (2,2,3,3, 3-pentafluoropropyl) phosphate.
Wherein the sulfur-containing compound is at least one selected from sulfolane, 2-methylsulfolane, 3-methylsulfolane, dimethylsulfone, diethylsulfone, ethylmethylsulfone, methylpropylsulfone, dimethylsulfoxide, methyl methanesulfonate, ethyl methanesulfonate, methyl ethanesulfonate, ethyl ethanesulfonate, dimethyl sulfate, diethyl sulfate and dibutyl sulfate.
Wherein the aromatic fluorine-containing compound is selected from m-fluorotoluene, p-fluorotoluene, fluorobiphenyl and fluorobenzene.
In one embodiment of the invention, the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis (fluorosulfonyl) imide, lithium difluoro oxalate borate, lithium bis (trifluoromethylsulfonyl) imide, lithium bis oxalate borate and lithium difluoro oxalate phosphate, and the lithium salt accounts for 8-25wt% of the total mass of the nonaqueous electrolytic solution.
As described above, the present invention also provides a method for preparing the above nonaqueous electrolytic solution, the method comprising:
mixing an organic solvent, a lithium salt and an additive which at least contains the polynitrile compound and accounts for 0.01-10wt% of the total weight of the non-aqueous electrolyte to prepare the electrolyte.
In one embodiment of the invention, the mixing is carried out at room temperature.
In one embodiment of the invention, the mixing is not limited by the order of addition.
As described above, the present invention also provides a lithium secondary battery comprising the above-described nonaqueous electrolytic solution.
In one aspect of the present invention, the lithium secondary battery further includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet. The diaphragm arranged between the positive plate and the negative plate can prevent the current short circuit caused by the contact of the two plates and can allow lithium ions to pass through.
In one aspect of the present invention, the anode includes an anode current collector and an anode active material layer disposed on one or both surfaces of the anode current collector.
Wherein, the negative current collector is selected from copper foil, such as electrolytic copper foil or rolled copper foil.
Wherein the anode active material layer includes an anode active material and an anode binder.
In some embodiments, the negative electrode active material is any material capable of deintercalating metal ions such as lithium ions.
In some embodiments, the negative active material may be one or more of graphite, a silicon material, a silicon-carbon composite material, a silicon-oxygen material, an alloy material, and a lithium-containing metal composite oxide material.
In some embodiments, the chargeable capacity of the negative electrode active material is greater than the discharge capacity of the positive electrode active material to prevent unintentional precipitation of lithium metal on the negative electrode during charging.
In some embodiments, the negative electrode binder includes, but is not limited to, one or more of styrene-butadiene rubber, fluorine-based rubber, and ethylene propylene diene, hydroxyalkyl methyl cellulose.
The negative electrode active material layer may further include a conductive agent, and the conductive agent may be at least one of graphite, carbon black, acetylene black, ketjen black, carbon nanotubes, and graphene.
In one aspect of the present invention, the positive electrode includes a positive electrode current collector and a positive electrode active material layer provided on one or both surfaces of the positive electrode current collector.
Wherein the positive electrode current collector is selected from aluminum foil.
Wherein the positive electrode active material layer includes a positive electrode active material and a positive electrode binder.
In some embodiments, the positive active material is a lithium-containing compound. The lithium-containing compound includes one or more of a lithium transition metal composite oxide and a lithium transition metal phosphate compound.
In some embodiments, the lithium transition metal composite oxide comprises lithium and an oxide having one or more transition metal elements.
In some embodiments, the lithium transition metal phosphate compound comprises lithium and a phosphate compound having one or more transition metal elements.
In some embodiments, the transition metal element includes one or more of Co, Ni, Mn, and Fe, which may allow the electrochemical device to obtain a higher voltage. Specific examples can be lithium cobaltate, ternary nickel cobalt manganese, lithium iron phosphate and other materials.
In some embodiments, the positive electrode binder may be a polymeric material including, but not limited to, polyvinylidene fluoride and polyimide.
The positive electrode may further include a conductive agent, and the conductive agent may be at least one of graphite, carbon black, acetylene black, ketjen black, carbon nanotubes, and graphene.
In one aspect of the invention, the separator is selected from porous films.
Wherein, the diaphragm is a porous film made of polymer.
In some embodiments, the polymers include, but are not limited to: polyethylene terephthalate, polybutylene terephthalate, polyether, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyether sulfone, polyphenylene ether, polyphenylene sulfide, polyethylene naphthalene, high density polyethylene, low density polyethylene, linear low density polyethylene, ultra high molecular weight polyethylene, and polypropylene.
In some embodiments, the separator further comprises an organic or inorganic coating disposed on one or both surfaces of the porous membrane.
In some embodiments, the inorganic substances may specifically include, but are not limited to: BaTiO 23、Pb(Zr，Ti)O3(PZT)、Pb1-xLaxZr1-yTiyO3、PB(Mg3Nb2/3)O3-PbTiO3Hafnium oxide (HfO)2)、SrTiO3、SnO2、CeO2、MgO、NiO、CaO、ZnO、ZrO2、SiO2、Y2O3、Al2O3、SiC、TiO2And mixtures thereof.
In some embodiments, the organic material may specifically include, but is not limited to: cyanoethylpullulan, cyanoethylpolyvinyl alcohol, cyanoethylcellulose, cyanoethylsucrose, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyimide, polyethylene oxide, cellulose acetate butyrate and cellulose acetate propionate, and mixtures thereof.
In one embodiment of the present invention, the specific surface area of the positive electrode active material is 0.1 to 1m2(ii)/g; further preferably 0.1 to 0.5m2/g。
In one embodiment of the invention, the specific surface area of the negative active material is 1-2 m2(ii)/g; further preferably 1.2 to 1.8m2Per g, preferably from 1.3 to 1.7m2/g。
The preparation method of the present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.
Example 1
A non-aqueous electrolyte consists of an organic solvent, a lithium salt and an additive, wherein the organic solvent is prepared from ethylene carbonate: propylene carbonate: diethyl carbonate (1: 2: 7) and the organic solvent accounted for 84.5 wt% of the total mass of the nonaqueous electrolytic solution. The lithium salt is lithium hexafluorophosphate accounting for 12.5 wt% of the total mass of the nonaqueous electrolyte. The additive was 1,3, 6-hexanetricarbonitrile containing 15.03ppm of acrylonitrile, which accounted for 3 wt% of the total mass of the nonaqueous electrolytic solution.
A lithium secondary battery includes a positive electrode sheet containing a positive electrode active material, a negative electrode sheet containing a negative electrode active material, a separator, and the above electrolyte. The positive active material is lithium cobaltate with a specific surface area of 0.34m2(ii) in terms of/g. The negative active material is graphite with a specific surface area of 1.41m2/g。
Example 2
A non-aqueous electrolyte consists of an organic solvent, a lithium salt and an additive, wherein the organic solvent is prepared from ethylene carbonate: propylene carbonate: propyl propionate: diethyl carbonate (2: 1:3: 4) and the organic solvent accounts for 82 wt% of the total mass of the nonaqueous electrolyte. The lithium salt is lithium hexafluorophosphate accounting for 15 wt% of the total mass of the nonaqueous electrolyte. The additive was 1,3, 6-hexanetricarbonitrile containing 45.68ppm of acrylonitrile, which accounted for 3 wt% of the total mass of the nonaqueous electrolytic solution.
The lithium secondary battery was fabricated by the same procedure as in example 1, except that the electrolyte of this example was used.
Example 3
A non-aqueous electrolyte consists of an organic solvent, a lithium salt and an additive, wherein the organic solvent is prepared from ethylene carbonate: propylene carbonate: ethyl propionate: propyl propionate: diethyl carbonate (2: 1:2:2: 3) and the organic solvent accounts for 84 wt% of the total mass of the nonaqueous electrolyte. The lithium salt is lithium hexafluorophosphate accounting for 13 wt% of the total mass of the nonaqueous electrolyte. The additive was 1,3, 6-hexanetricarbonitrile containing 33.38ppm of acrylonitrile, which accounted for 3 wt% of the total mass of the nonaqueous electrolytic solution.
A lithium secondary battery was fabricated by the same procedure as in example 1, except that the electrolyte of this example was used, and the specific surface area of the selected negative electrode active material was 1.6m2/g。
Comparative example 1
The electrolyte was prepared in the same manner as in example 1 except that 2.98ppm of acrylonitrile was contained in 1,3, 6-hexanetricarbonitrile.
The lithium secondary battery was fabricated by the same procedure as in example 1, except that the electrolyte of this example was used.
Comparative example 2
The electrolyte was prepared in the same manner as in example 1 except that 68.23ppm of acrylonitrile was contained in 1,3, 6-hexanetricarbonitrile.
The lithium secondary battery was fabricated by the same procedure as in example 1, except that the electrolyte of this example was used.
Comparative example 3
The electrolyte was prepared in the same manner as in example 1.
The lithium secondary battery was fabricated by the same procedure as in example 1, except that the negative active material having a specific surface area of 2.4m was used2/g。
Comparative example 4
The electrolyte was prepared in the same manner as in example 1.
The lithium secondary battery was fabricated by the same procedure as in example 1, except that the positive electrode active material having a specific surface area of 1.3m was used2/g。
Comparative example 5
The procedure for preparing an electrolyte was the same as in example 1 except that 1,3, 6-hexanetricarbonitrile was added in an amount of 15% by weight based on the total mass of the nonaqueous electrolyte.
The lithium secondary battery was fabricated by the same procedure as in example 1, except that the electrolyte of this example was used.
The lithium secondary batteries of examples and comparative examples were subjected to high-temperature cycle tests under the following specific test conditions:
high-temperature cycle test: the battery is placed at 45 ℃, the charge-discharge cycle is carried out by using 1C current in the charge-discharge voltage interval of 3-4.5V, the maximum capacity of the battery in the first three times is recorded as Q, and the capacity of the battery in the cycle of 300 weeks is selected as Q2The capacity retention after high temperature cycling of the battery was calculated by the following formula: capacity retention (%) ═ Q2/Q×100。
As shown in the above table and fig. 1, it can be seen from the results listed in the above table and fig. 1 that the examples have significant advantageous effects, specifically, the capacity retention rate after high temperature cycling is significantly improved, compared to the comparative examples, indicating that the lithium secondary battery obtained by using the electrolyte solution of the present invention has outstanding advantages.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (12)
1. A lithium secondary battery is characterized by comprising a non-aqueous electrolyte, a positive plate, a negative plate and a diaphragm, wherein the diaphragm is arranged between the positive plate and the negative plate; wherein the specific surface area of the positive active material in the positive plate is 0.1-1 m2The specific surface area of the negative active material in the negative plate is 1-2 m2/g；
The non-aqueous electrolyte comprises an organic solvent, an additive and a lithium salt, wherein the additive at least contains a polynitrile compound; the dosage of the additive accounts for 0.01 to 10 weight percent of the total weight of the nonaqueous electrolyte; the polynary nitrile compound is prepared from low-element nitrile compounds, and the content of the low-element nitrile compounds in the polynary nitrile compounds is 5-60 ppm;
the low-nitrile compound refers to a nitrile compound in which the number of cyano CN groups is less than that of a polynary nitrile compound.
2. The lithium secondary battery according to claim 1, wherein the low-order nitrile compound is selected from compounds having a structure represented by formula (1):
In the formula (1), R1And R2Identical or different, independently of one another, from H, halogen, alkyl or aryl; r3Selected from H, halogen, alkyl or aryl; when R is1And R3When selected from hydrocarbon groups, they may be linked to each other to form a ring, i.e., a compound having a structure represented by the following formula (2):
In the formula (2), R2Is as defined in formula (1); r'1And R'3Are each R1And R3By removal of one H group, R1And R3Identical or different, independently of one another, from the group of hydrocarbon radicals.
3. The lithium secondary battery according to claim 1 or 2, the nonaqueous electrolytic solution comprising an organic solvent, an additive containing at least 1,3, 6-hexanetricarbonitrile, and a lithium salt; the dosage of the additive accounts for 0.01 to 10 weight percent of the total weight of the nonaqueous electrolyte; the content of acrylonitrile in the 1,3, 6-hexanetricarbonitrile is 5-60 ppm.
4. The lithium secondary battery according to claim 3, wherein the content of acrylonitrile in the 1,3, 6-hexanetricarbonitrile is 5 to 58 ppm.
5. The lithium secondary battery according to claim 4, wherein the content of acrylonitrile in the 1,3, 6-hexanetricarbonitrile is 7 to 55 ppm.
6. The lithium secondary battery according to claim 5, wherein the content of acrylonitrile in the 1,3, 6-hexanetricarbonitrile is 8 to 53 ppm.
7. The lithium secondary battery according to claim 6, wherein the content of acrylonitrile in the 1,3, 6-hexanetricarbonitrile is 8.99 to 51.99 ppm.
8. The lithium secondary battery according to claim 7, wherein the content of acrylonitrile in the 1,3, 6-hexanetricarbonitrile is 9.99 to 31.99 ppm.
9. The lithium secondary battery as claimed in claim 1 or 2, wherein the additive is used in an amount of 0.1 to 5wt% based on the total weight of the nonaqueous electrolytic solution.
10. The lithium secondary battery as claimed in claim 9, wherein the additive is used in an amount of 0.5 to 2wt% based on the total weight of the nonaqueous electrolytic solution.
11. The lithium secondary battery according to claim 1 or 2, wherein the organic solvent is at least one selected from the group consisting of carbonates, carboxylates, ether compounds, phosphorus-containing compounds, sulfur-containing compounds, and aromatic fluorine-containing compounds.
12. The lithium secondary battery according to claim 1 or 2, wherein the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis (fluorosulfonyl) imide, lithium difluorooxalato borate, lithium bis (trifluoromethanesulfonyl) imide and lithium bis (oxalato) borate, lithium difluorooxalato phosphate, and the lithium salt accounts for 8 to 25wt% of the total mass of the nonaqueous electrolytic solution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911144466.8A CN112825373B (en) | 2019-11-20 | 2019-11-20 | Non-aqueous electrolyte and lithium secondary battery comprising same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911144466.8A CN112825373B (en) | 2019-11-20 | 2019-11-20 | Non-aqueous electrolyte and lithium secondary battery comprising same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112825373A CN112825373A (en) | 2021-05-21 |
| CN112825373B true CN112825373B (en) | 2022-06-14 |
Family
ID=75907050
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911144466.8A Active CN112825373B (en) | 2019-11-20 | 2019-11-20 | Non-aqueous electrolyte and lithium secondary battery comprising same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112825373B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114400379A (en) * | 2022-01-20 | 2022-04-26 | 湖南科技大学 | Preparation method of high-safety high-voltage electrolyte containing nitrile compounds |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1341589A (en) * | 2000-07-06 | 2002-03-27 | 拜尔公司 | Process for preparing aliphatic trinitrile |
| CN102110846A (en) * | 2009-12-25 | 2011-06-29 | 三洋电机株式会社 | Nonaqueous secondary battery |
| CN104387291A (en) * | 2014-11-07 | 2015-03-04 | 苏州亚科化学试剂股份有限公司 | Preparation method of 1,3,6-hexanetricarbonitrile |
| CN104852087A (en) * | 2015-04-15 | 2015-08-19 | 宁德时代新能源科技有限公司 | Electrolyte additive and lithium ion battery using the same |
| CN105037203A (en) * | 2015-08-27 | 2015-11-11 | 石家庄圣泰化工有限公司 | Preparation method of 1,3,6-hexanetricarbonitrile |
| CN109473713A (en) * | 2018-12-19 | 2019-03-15 | 珠海光宇电池有限公司 | A kind of high-voltage electrolyte for taking into account high temperature performance and the lithium ion battery using the electrolyte |
| CN109841831A (en) * | 2019-03-21 | 2019-06-04 | 宁德新能源科技有限公司 | Negative electrode material and cathode and electrochemical appliance comprising the negative electrode material |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101580478B (en) * | 2009-06-17 | 2012-07-04 | 武汉工程大学 | Method for synthesizing three direction dendrimer core by microwave |
| KR20190054920A (en) * | 2017-11-14 | 2019-05-22 | 주식회사 엘지화학 | Electrolyte for lithium secondary battery and lithium secondary battery comprising the same |
| CN108033900A (en) * | 2017-12-25 | 2018-05-15 | 惠州市宙邦化工有限公司 | A kind of discoloration method of three nitrile of 1,3,6- hexanes |
| CN109301326B (en) * | 2018-09-21 | 2020-11-27 | 宁德新能源科技有限公司 | Electrolyte and electrochemical device |
-
2019
- 2019-11-20 CN CN201911144466.8A patent/CN112825373B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1341589A (en) * | 2000-07-06 | 2002-03-27 | 拜尔公司 | Process for preparing aliphatic trinitrile |
| CN102110846A (en) * | 2009-12-25 | 2011-06-29 | 三洋电机株式会社 | Nonaqueous secondary battery |
| CN104387291A (en) * | 2014-11-07 | 2015-03-04 | 苏州亚科化学试剂股份有限公司 | Preparation method of 1,3,6-hexanetricarbonitrile |
| CN104852087A (en) * | 2015-04-15 | 2015-08-19 | 宁德时代新能源科技有限公司 | Electrolyte additive and lithium ion battery using the same |
| CN105037203A (en) * | 2015-08-27 | 2015-11-11 | 石家庄圣泰化工有限公司 | Preparation method of 1,3,6-hexanetricarbonitrile |
| CN109473713A (en) * | 2018-12-19 | 2019-03-15 | 珠海光宇电池有限公司 | A kind of high-voltage electrolyte for taking into account high temperature performance and the lithium ion battery using the electrolyte |
| CN109841831A (en) * | 2019-03-21 | 2019-06-04 | 宁德新能源科技有限公司 | Negative electrode material and cathode and electrochemical appliance comprising the negative electrode material |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112825373A (en) | 2021-05-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6673225B2 (en) | Non-aqueous electrolyte and power storage device using the same | |
| CN110176630B (en) | Electrolyte solution and electrochemical device using the same | |
| CN113206296A (en) | Electrolyte solution, electrochemical device, and electronic device | |
| JP2013118168A (en) | Nonaqueous electrolyte secondary battery | |
| JP7399626B2 (en) | Non-aqueous electrolyte and energy devices using it | |
| CN107210489B (en) | Nonaqueous electrolyte solution and nonaqueous electrolyte secondary battery | |
| KR20160091077A (en) | Organic electrolytic solution and Lithium battery comprising the solution | |
| CN111640985A (en) | Non-aqueous electrolyte and high-voltage lithium ion battery containing same | |
| CN111430794B (en) | Electrolyte, electrochemical device and electronic device | |
| CN116314595B (en) | Secondary battery and device | |
| CN112635823A (en) | High-voltage lithium cobalt oxide lithium ion battery electrolyte and lithium ion battery | |
| CN112825370A (en) | Non-aqueous electrolyte and lithium ion battery containing same | |
| WO2021065863A1 (en) | Non-aqueous electrolyte solution and power storage device using same | |
| KR20190018941A (en) | Disulfonate-based additive and Lithium secondary battery comprising the same | |
| CN112825373B (en) | Non-aqueous electrolyte and lithium secondary battery comprising same | |
| CN111354946B (en) | Positive electrode material, and electrochemical device and electronic device using same | |
| KR20190012364A (en) | Additive for nonaqueous electrolyte, nonaqueous electrolyte for lithium secondary battery comprising the same, and lithium secondary battery | |
| CN113661595B (en) | Electrolyte for lithium secondary battery and lithium secondary battery comprising same | |
| CN115152058A (en) | Electrochemical device and electronic device including the same | |
| CN112825369B (en) | High-voltage lithium ion battery with excellent high-temperature performance | |
| CN114616709A (en) | Electrolyte additive for secondary battery, nonaqueous electrolyte for lithium secondary battery, and lithium secondary battery comprising same | |
| CN117457910B (en) | Positive pole piece and sodium ion battery | |
| CN116487706B (en) | Secondary battery and device | |
| TW201840548A (en) | Additive for non-aqueous electrolyte, non-aqueous electrolyte, and power storage device | |
| CN116404258B (en) | Secondary battery and 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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |