A kind of lithium-ion battery electrolytes and the lithium ion battery using the electrolyte
Technical field
The invention belongs to lithium ion battery material technical fields, and in particular to a kind of lithium-ion battery electrolytes and using should
The lithium ion battery of electrolyte.
Background technique
Lithium ion battery is since commercialization, and due to the light of it, specific energy is high, memory-less effect, good cycle,
It is widely used in the fields such as number, energy storage, power, militay space flight and communication apparatus.With the extensive use of lithium ion battery, disappear
More stringent requirements are proposed to performances such as the energy density of lithium ion battery, cycle life, high-temperature behavior, safeties by the person of expense.
The mode for improving energy density has following two, the charging voltage of battery on the one hand can be improved, using charging electricity
Press higher anode, improve using technique the voltage of existing battery or the nickelic positive electrode using high capacity, as NMC622,
NMC811, NCA etc.;It on the other hand can be using negative electrode materials such as the silicon-carbons of high-energy density, to improve the energy of battery.But
Voltage or unstable using nickelic positive electrode surface is improved, the transition metal ions on surface is in high oxidation state, causes to be electrolysed
Liquid is oxidized easily, and transition metal ions is caused to dissolve out, and furthermore nickelic positive electrode surface is unstable, there are problems that analysing oxygen;For negative
For pole, if the dissolution of positive transition metal ions moves to cathode and can destroy cathode SEI film, for its surface of silicon-carbon cathode
SEI film is unstable, is more easily damaged in charge and discharge process, therefore will lead to the deterioration of high energy density cells performance.
An important factor for electrolyte is influence performance of lithium ion battery, and additive therein is wherein crucial group
Point, the electrical property of lithium ion battery can be significantly improved by one or more kinds of additives.Such as: application No. is
The invention " electrolyte and lithium ion battery " of CN201610304130.3, discloses lithium hexafluoro phosphate (LiPF6) and double fluorine sulphonyl
Imine lithium (LiFSI) organizes carboxylic ester and/or alpha-fluorocarboxylate ester;Carbonic ester and/or fluoro carbonic ester;And sulfone, it is glued
Spend that low, ionic conductivity is good, can be used for the lithium ion battery of 4.5V and the above voltage.Sulfone and fluoro carbonic ester content height will lead to
Viscosity is big, and the viscosity of fluoro carbonic ester and sulfone can be effectively reduced in carboxylate, alpha-fluorocarboxylate ester, therefore it is lower to assign electrolyte
Viscosity and higher ionic conductivity.The addition of sulfone class will lead to that battery capacity is relatively low and cathode interface is bad, and carboxylate
The high temperature storage of battery and high temperature cyclic performance need further research textual criticism when content is higher.
The lithium salts of lithium-ion battery electrolytes is most of using lithium hexafluoro phosphate at present, research shows that in electrolyte
Lithium hexafluoro phosphate (LiPF6) can decompose generates PF5And LiF, PF5It is strong lewis acid, can reacts with solvent and especially exist
Lead to battery producing gas under high temperature, furthermore lithium hexafluoro phosphate (LiPF6) under the action of trace water, it can be reacted with water and generate LiF,
POF3And HF, HF can corrode the transition metal ions of positive electrode surface, and transition metal ions is caused to dissolve out, and destroy anode, move simultaneously
The SEI of cathode can be also destroyed if moving on to cathode, to influence the electrical property of battery.
Summary of the invention
The purpose of the present invention is to solve the resolution problem of lithium salts in existing lithium battery and itself and trace water occur it is secondary
Reaction leads to problems such as battery producing gas or performance deteriorate, provide a kind of lithium-ion battery electrolytes and using the electrolyte lithium from
Sub- battery.
To achieve the above object, the technical solution adopted by the present invention is as follows:
A kind of lithium-ion battery electrolytes, including organic solvent, lithium salts and additive, the organic solvent include A and/
Or B, the A are carbonic ester or fluoro carbonic ester, the B is carboxylate or alpha-fluorocarboxylate ester;The lithium salts includes six
Lithium fluophosphate, in addition, the lithium salts further includes bis trifluoromethyl sulfimide and/or bis- (fluorine sulphonyl) imine lithiums;Described
Additive includes cathode film formation additive and/or anode protection additive.
A kind of lithium ion battery containing above-mentioned electrolyte, the lithium ion battery include containing positive electrode active materials
Positive plate, the negative electrode tab containing negative electrode active material, lithium-ion membrane, binder and electrolyte.
The beneficial effect of the present invention compared with the existing technology is: the present invention uses the bis trifluoromethyl sulfimide of high-content
And/or lithium hexafluoro phosphate (the LiPF of bis- (fluorine sulphonyl) imine lithium part substitution routines6) lithium salts, since bis trifluoromethyl sulphonyl is sub-
Amine and/or bis- (fluorine sulphonyl) imine lithium substances itself compare that lithium hexafluoro phosphate is more stable, they do not have hexafluoro phosphorus to the reaction of water
Sour lithium is sensitive, and bis trifluoromethyl sulfimide and/or bis- (fluorine sulphonyl) imine lithiums can improve high temperature storage and high temperature circulation
Can, therefore the bis trifluoromethyl sulfimide and/or bis- (fluorine sulphonyl) imine lithiums of suitable lithium hexafluoro phosphate combination high-content, it can subtract
Few lithium hexafluoro phosphate decomposes the PF generated since its own high temperature is unstable5, the harmful substances such as HF, while double trifluoros of high-content
Sulfonyloxy methyl imines and/or bis- (fluorine sulphonyl) imine lithiums can provide the lithium ion of a part, and such lithium ion solubility increases, can
To reduce the usage amount of lithium hexafluoro phosphate to a certain extent, and then slow down lithium hexafluoro phosphate decomposition, reduces PF5Etc. harmful substances
Solubility, while reducing lithium hexafluoro phosphate because the side reaction that trace water generates is formed by the harmful substance contents such as HF, improve electricity
Pond performance.In conjunction with cathode film formation additive appropriate and/or anode protection additive, can improve battery high temperature circulation and
High-temperature storage performance.
Specific embodiment
Below with reference to embodiment, further description of the technical solution of the present invention, and with high voltage cobalt acid lithium (LCO)
Anode does specific description with graphite cathode battery, but positive and negative anodes of the invention are not limited thereto, all to the technology of the present invention
Scheme is modified or replaced equivalently, and without departing from the spirit and scope of the technical solution of the present invention, should all be covered in the present invention
Protection scope in.
Specific embodiment 1: present embodiment record is a kind of lithium-ion battery electrolytes, including organic solvent, lithium
Salt and additive, the organic solvent include A and/or B, and the A is carbonic ester or fluoro carbonic ester, and the B is carboxylic
Acid esters or alpha-fluorocarboxylate ester;The lithium salts includes lithium hexafluoro phosphate (LiPF6), in addition, the lithium salts further includes high-content
Bis trifluoromethyl sulfimide (LiTFSI) and/or bis- (fluorine sulphonyl) imine lithiums (LiFSI);The additive include cathode at
Film additive and/or anode protection additive.
Specific embodiment 2: a kind of lithium-ion battery electrolytes described in specific embodiment one, the carbonic ester
For one or more of ethylene carbonate, propene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate;Described
Carboxylate be propyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, ethyl propionate, propionic acid just
One or more of propyl ester, methyl butyrate, ethyl butyrate or fluorinated solvents of above-mentioned solvent.
Specific embodiment 3: a kind of lithium-ion battery electrolytes described in specific embodiment one, the hexafluoro phosphorus
Sour lithium (LiPF6) mass fraction shared in the electrolytic solution is 5%~20%, preferably 8%~14%;Double fluoroforms
Shared mass fraction is 0.5%~8%, preferably 3%~6% to base sulfimide (LiTFSI) in the electrolytic solution;Described
Shared mass fraction is 0.5%~6%, preferably 1%~4% to bis- (fluorine sulphonyl) imine lithiums (LiFSI) in the electrolytic solution.
Specific embodiment 4: one of specific embodiment one or three lithium-ion battery electrolytes, the lithium salts
It further include LiBF4 (LiBF4), bis- (oxalic acid) lithium borates (LiBOB), difluoro (oxalic acid) lithium borate (LiODFB), difluoro two
Oxalic acid lithium phosphate (LiDFOP), tetrafluoro oxalic acid lithium phosphate (LiTFOP), difluorophosphate (LiPO2F2), trifluoromethyl sulfonic acid lithium
(LiSO3CF3One or more of).
Specific embodiment 5: a kind of lithium-ion battery electrolytes described in specific embodiment one, the cathode at
Film additive is vinylene carbonate (VC), fluorinated ethylene carbonate (FEC), 1,3-propane sultone (1,3-PS), carbonic acid second
One of alkene ethyl (VEC), sulfuric acid vinyl ester (DTD), ethylene sulfite (ES), methane-disulfonic acid methylene ester (MMDS)
Or it is a variety of.
Specific embodiment 6: a kind of lithium-ion battery electrolytes described in specific embodiment one, the anode is protected
Shield additive is 1,3-propane sultone (1,3-PS), vinylethylene carbonate (VEC), sulfuric acid vinyl ester (DTD), two sulphur of methane
Sour methylene ester (MMDS), propene sultone (RPS), succinonitrile (SN), glutaronitrile, adiponitrile (ADN), pimelic dinitrile, hexamethylene dicyanide,
Certain herbaceous plants with big flowers dintrile etc., 1, bis- (propionitrile) ethers of 3,6- hexane, three nitrile (HTCN), ethylene glycol, 1,2- bis- (2- cyanoethoxyl) ethane (DENE),
1,2- bis- (2- cyanoethoxyl) ethane, 1, one or more of 2,3- tri--(2- cyanoethoxyl) propane.
Specific embodiment 7: a kind of contain electrolyte described in any specific embodiment of specific embodiment one to six
Lithium ion battery, the lithium ion battery includes the positive plate containing positive electrode active materials, containing negative electrode active material
Negative electrode tab, lithium-ion membrane, binder and electrolyte.
Specific embodiment 8: lithium ion battery described in specific embodiment seven, the positive plate is Layered Lithium
Composite oxides, LiMn2O4, cobalt acid lithium mix one or more of ternary material, and the stratiform lithium composite xoide general formula is
Li1+xNiyCozM(1-y-z)Y2, wherein -0.1≤x≤1;0≤y≤1,0≤z≤1, and 0≤y+z≤1;Wherein, M Mg, Zn,
One or more of Ga, Ba, Al, Fe, Cr, Sn, V, Mn, Sc, Ti, Nb, Mo, Zr;Y is one or more of O, F, P.
Specific embodiment 9: lithium ion battery described in specific embodiment one, the negative electrode tab be carbon materials,
Silica-base material, tin-based material or their corresponding alloy materials.
Specific embodiment 10: lithium ion battery described in specific embodiment one, contain in the negative electrode active material
One or more of carbon, silicon, tin.
The operating voltage range of lithium ion battery of the present invention is 4.2V and the above voltage.
(1) prepared by positive plate
Positive electrode active materials 4.45V cobalt acid lithium (LCO), binder Kynoar (PVDF), conductive agent acetylene black are pressed
Mixed according to weight ratio 97.5:1.5:1.5, be added N-Methyl pyrrolidone (NMP), de-airing mixer effect under stir to
System at uniform flow anode sizing agent;Anode sizing agent is evenly applied on the aluminium foil with a thickness of 10~13 μm;By aluminium foil
It is transferred to 120 DEG C of oven drying 6-9h after room temperature is dried, then obtains positive plate by roll-in, cutting.
(2) prepared by negative electrode tab
Negative electrode active material graphite, thickener sodium carboxymethylcellulose (CMC), binder butadiene-styrene rubber, conductive agent are pressed
It is mixed according to weight ratio 97:1:1:1, deionized water is added, obtain negative electrode slurry under de-airing mixer effect;Cathode is starched
Material is coated uniformly on the copper foil with a thickness of 6-8 μm;Copper foil is transferred to 120 DEG C of oven drying 1h after room temperature is dried, then
By being cold-pressed, cutting to obtain negative electrode tab.
(3) prepared by electrolyte
Full of argon gas water oxygen content qualification glove box in, by ethylene carbonate, propene carbonate, diethyl carbonate,
N propyl propionate is uniformly mixed according to the ratio of mass ratio 20:10:25:45, then rapidly joins the abundant of 10wt% thereto
Dry lithium hexafluoro phosphate (LiPF6), it is dissolved in organic solvent, is eventually adding and accounts for electrolyte total amount weight 3.8wt%1,3-
Propane sultone (1,3-PS), 5.5wt% fluorinated ethylene carbonate (FEC), the adiponitrile of the succinonitrile (SN) of 1wt%, 2wt%
(ADN), 0.5wt%2- bis- (2- cyanoethoxyl) ethane (DENE), the electrolyte being uniformly mixing to obtain in embodiment 1.
(4) preparation of isolation film
The polyethylene separators (Asahi Kasei Corporation's offer) of 7~9 μ m-thicks are provided.
(5) preparation of lithium ion battery
The positive plate, isolation film, negative electrode tab of above-mentioned preparation are stacked in order, guarantee that isolation film is in positive and negative plate
Between play the role of isolation, then by winding obtain the naked battery core of non-fluid injection;Naked battery core is placed in outer packing foil, it will be upper
It states in the naked battery core after the electrolyte prepared is injected into drying, by works such as Vacuum Package, standing, chemical conversion, shaping, sortings
Sequence obtains required lithium ion battery.
Electrolyte is substantially according to the preparation in above-mentioned electrolyte quota, here the area of the electrolyte of embodiment and comparative example
It is not listed as follows:
Type |
LiPF6 |
LiTFSI |
LiFSI |
Embodiment 1 |
13.8% |
1% |
|
Embodiment 2 |
11.8% |
3% |
|
Embodiment 3 |
9.8% |
5% |
|
Embodiment 4 |
8.8% |
6% |
|
Embodiment 5 |
13.8% |
|
1% |
Embodiment 6 |
13.3% |
|
1.5% |
Embodiment 7 |
12.8% |
|
2% |
Embodiment 8 |
10.8% |
|
4% |
Embodiment 9 |
8.8% |
|
6% |
Embodiment 10 |
11.3% |
2% |
1% |
Embodiment 11 |
9.0% |
3% |
1.5% |
Embodiment 12 |
9.0% |
4% |
2% |
Comparative example 1 |
14.8% |
|
|
Comparative example 2 |
14.3% |
0.3% |
|
Comparative example 3 |
14.5% |
|
0.3% |
Dependence test is described as follows:
High temperature storage experiment:
Under conditions of 25 DEG C ± 3 DEG C of environment temperature, battery/battery core is with 0.5C constant-current discharge to blanking voltage, with 0.7C/
0.5C cut-off current 0.025C charge and discharge, record initially expire capacitance Q0, the thickness D of the full electric battery/battery core of test later0;
Fully charged battery core is opened a way under the conditions of (60 ± 2) DEG C shelve 30 days after, at room temperature open circuit shelve 2h, survey
Try cooling thickness D1;With 0.5C constant-current discharge to blanking voltage, it is denoted as residual capacity Q1;Again with 0.7C/0.5C cut-off current
0.025C charge and discharge 3 times, peak capacity, which is denoted as, restores capacity Q2。
Thickness change (%)=(D1-D0)/D0* 100%
Capacity retention ratio (%)=Q1/Q0* 100%
Capacity restoration rate (%)=Q2/Q0* 100%
45 DEG C of high temperature circulation experiments:
The thickness D of the full electric battery core of test before test0, battery is placed in (45 ± 2) DEG C environment, 1.5-3 hour is stood,
When battery core body reaches (45 ± 2) DEG C, battery records initial capacity according to 0.7C/0.5C cut-off current 0.025C charge and discharge
Q0, when circulation reaches required number, the full electricity of battery records the capacity Q of battery1, after battery core is taken out, it is small that room temperature stands 1-3
When, test full electric thickness D1.Record result such as table 1.
The meter formula wherein used is as follows:
Thickness change (%)=(D1-D0)/D0* 100%
Capacity retention ratio (%)=Q1/Q0* 100%
55 DEG C of high temperature circulation experiments:
The thickness D of the full electric battery core of test before test0, battery is placed in (55 ± 2) DEG C environment, 1.5-3 hour is stood,
When battery core body reaches (55 ± 2) DEG C, battery records initial capacity according to 0.5C/0.5C charge and discharge, cut-off current 0.025C
Q0, when circulation reaches required number, the full electricity of battery records the capacity Q of battery1, after battery core is taken out, it is small that room temperature stands 1-3
When, test electric thickness D full at this time1.Record result such as table 1.
The meter formula wherein used is as follows:
Thickness change (%)=(D1-D0)/D0* 100%
Capacity retention ratio (%)=Q1/Q0* 100%
The comparison of 1 embodiment and comparative example experimental result of table
It is compared by comparative example 1,2 and embodiment 1-4, illustrates that the bis trifluoromethyl sulfimide (LiTFSI) of high-content can
To be obviously improved the thickness swelling and capacity retention ratio of circulating battery, while improving the high-temperature storage performance of battery, and with
Bis trifluoromethyl sulfimide (LiTFSI) content increase, more preferably, low content improvement is unobvious for improvement.By right
Ratio 1,3 and embodiment 5-9 illustrate that bis- (fluorine sulphonyl) imine lithiums (LiFSI) of high-content can be obviously improved circulating battery
Thickness swelling and capacity retention ratio improve the high-temperature storage performance of battery.Comparative example 5-7 and 10-12 and embodiment 4
With embodiment 12, it can be found that considering bis trifluoromethyl sulfimide (LiTFSI) and bis- (fluorine sulphonyl) imine lithiums (LiFSI)
Combined effect than single bis trifluoromethyl sulfimide (LiTFSI) or bis- (fluorine sulphonyl) imine lithium (LiFSI) high temperature circulation and
High-temperature storage performance is more excellent.
It is to be illustrated for possible embodiments of the invention above, but positive and negative electrode of the invention, electrolyte not office
It is limited to this, all modifying or equivalently replacing the technical solution of the present invention, without departing from the spirit of the technical scheme of the invention
And range, it should all cover within the protection scope of the present invention.