CN107293797A - Lithium secondary battery - Google Patents
Lithium secondary battery Download PDFInfo
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- CN107293797A CN107293797A CN201710550316.1A CN201710550316A CN107293797A CN 107293797 A CN107293797 A CN 107293797A CN 201710550316 A CN201710550316 A CN 201710550316A CN 107293797 A CN107293797 A CN 107293797A
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- lithium
- secondary battery
- lithium secondary
- stratum granulosum
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- 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
- H01M10/058—Construction or manufacture
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- 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
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- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
The present invention relates to field of batteries, a kind of lithium secondary battery is disclosed, the lithium secondary battery includes：Positive pole, negative pole and electrolyte, the negative material of the negative pole include lithium matrix, form lithium metal stratum granulosum and the conformal protective layer for being covered in lithium metal particle layer surface in lithium matrix surface；The porosity of the lithium metal stratum granulosum is 10 80%；The protective layer contains lithium salts, and the anion of the lithium salts is selected from F‑、CO3 2‑、PO4 3‑、TFSI‑、FSI‑、OH‑、SO3 ‑、R1‑COO‑At least one of with trifluoromethanesulfonic acid radical ion, R1For C1‑C20Alkyl.The lithium secondary battery that the present invention is provided can overcome existing lithium secondary battery cathode material to be partially formed the defect that Li dendrite causes battery short circuit to trigger safety problem.
Description
Technical field
The present invention relates to field of batteries, and in particular to a kind of lithium secondary battery.
Background technology
Lithium metal is due to higher theoretical specific capacity (3860mAhg-1), low-density (0.59gcm-3) and it is most negative
Oxidation-reduction potential (- 3.040Vvs. standard hydrogen electrodes) and be considered as preferable secondary battery cathode material.With lithium from
Sub- battery technology is more and more ripe, and actual capacity becomes closer to theoretical capacity, and lithium ion battery is difficult to have again big breakthrough, because
This, it is difficult to meet the requirement that practical application is increasingly improved to lithium ion battery.Safe and efficient lithium metal battery will gradually replace
Lithium ion battery turns into energy storage device of future generation.And the security of battery is directly connected to the problem of dendrite, so seeking effectively
Method suppress development of the growth to secondary cell of Li dendrite and have great importance.
At present, as GND there is following defect in lithium metal：(1) lithium metal as GND in circulating battery mistake
The generation of Li dendrite easily penetrates battery diaphragm so as to cause internal short-circuit of battery in journey, and serious meeting causes battery catches fire blast to be deposited
In major safety risks；(2) constantly have the generation and decomposition of Li dendrite in charge and discharge process, electrode current density it is uneven
Distribution make it that the decomposition rate of dendrite is also uneven, and then causes the deposition of " dead lithium " to shorten the service life of battery；Dendrite
The side reaction that increases in the contact area of lithium metal and electrolyte, battery of growth increase electrolyte and lithium metal disappeared
Consumption, so as to cause low coulombic efficiency and low energy density.For drawbacks described above, the shape of Li dendrite in past 40 years
Extensive research is obtained for into process and suppressing method, most method concentrates on the mechanical strength and bullet of enhancing SEI films
Property intensity, can effectively stop after dendritic growth goes out, so that reducing or remitting dendrite penetrates barrier film and the continuous breaking, regenerating of SEI films
Process.But thermodynamics is unstable to lithium metal in organic solvent, is hardly formed at the interface of lithium electrode and liquid solvent
Inertia and stable film.Based on this, researchers start sight being placed in the modification to electrode/electrolyte interface.Document
(Nature Nanotechnology, 2014,9,618-623) is reported by one layer of nanometer of lithium anode superficial growth
The method of empty carbon ball is to form evenly stable SEI films so as to reach the purpose of suppression lithium dendrite growth, and this Stability Analysis of Structures has
There is higher Young's modulus, but preparation method is complicated, and cost is higher, it is impossible to reach the purpose of batch production.Document
(J.Am.Chem.Soc.2013,135,4450) is less than the cesium ion of lithium ion as electrolysis additive using sedimentation potential,
Negative terminal surface one layer of cesium ion protective layer of formation causes the deposition of lithium ion in negative terminal surface evenly, but this method it is inapplicable with
Circulation under high current degree.Many electrolysis additives can effectively strengthen the stability of SEI films, such as K.Kanamura et al.
It was found that add appropriate HF in the electrolytic solution is rich in LiF/Li in negative terminal surface formation2O SEI films, the lithium metal for making deposition is in
Reveal hemispherical, can dendrite inhibition formation.But the continuous consumption of additive causes this method not to be suitable for secondary cell
Circulate for a long time.
Therefore, it is urgently to be resolved hurrily the problem of Li dendrite in lithium secondary battery cyclic process.
The content of the invention
Li dendrite is also easy to produce in lithium secondary battery cyclic process the invention aims to overcome prior art presence
The problem of defect there is provided a kind of new lithium secondary battery.The lithium secondary battery that the present invention is provided can overcome existing lithium secondary
Cell negative electrode material is partially formed the defect that Li dendrite causes battery short circuit to trigger safety problem.
The present inventor has found that the formation of Li dendrite is mainly derived from lithium anode surface lithium in research process
The nonuniform deposition of ion.Therefore change lithium anode surface pattern promote lithium anode surface field to be uniformly distributed can
Fundamentally to solve the growth question of Li dendrite.
Based on this, the invention provides a kind of lithium secondary battery, the lithium secondary battery includes：Positive pole, negative pole and electrolyte,
The negative material of the negative pole include lithium matrix, formed lithium matrix surface lithium metal stratum granulosum and conformal be covered in metal
The protective layer of lithium particle layer surface；
Wherein, the porosity of the lithium metal stratum granulosum is 10-80%；The protective layer contains lithium salts, the lithium salts
Anion is selected from F-、CO3 2-、PO4 3-、TFSI-、FSI-、OH-、SO3 -、R1-COO-With at least one in trifluoromethanesulfonic acid radical ion
Kind, R1For C1-C20Alkyl.
The lithium secondary battery that the present invention is provided has unique lithium anode material surface pattern, can increase lithium metal
The contact area of negative pole and electrolyte, deposits for lithium ion and provides uniform point that more avtive spots promote surface charge
Cloth, so as to fundamentally reach the purpose for suppressing lithium dendrite growth.In addition, the negative pole material for the lithium secondary battery that the present invention is provided
Material surface distributed one layer of protective layer containing lithium salts, can be also easy to produce dendrite efficiently against common metal cathode of lithium interfacial instability
Defect.
The lithium secondary battery that the present invention is provided can overcome existing lithium secondary battery cathode material to be partially formed Li dendrite to lead
Battery short circuit is caused to trigger the defect of safety problem.The lithium secondary battery that the present invention is provided has higher coulombic efficiency and circulation steady
It is qualitative.
Brief description of the drawings
Accompanying drawing is, for providing a further understanding of the present invention, and to constitute a part for specification, with following tool
Body embodiment is used to explain the present invention together, but is not construed as limiting the invention.In the accompanying drawings：
Fig. 1 is the lithium anode material S1 obtained in embodiments of the invention 1 SEM figures；
Fig. 2 is the lithium anode material S1 obtained in embodiments of the invention 1 X-ray diffraction spectrogram；
Fig. 3 is the lithium anode material S1 obtained in embodiments of the invention 1 XPS figures；
The SEM figures for the lithium anode material D1 that Fig. 4 is obtained in the comparative example 1 for the present invention.
Embodiment
The end points and any value of disclosed scope are not limited to the accurate scope or value herein, these scopes or
Value should be understood to comprising the value close to these scopes or value.For number range, between the endpoint value of each scope, respectively
It can be combined with each other between the endpoint value of individual scope and single point value, and individually between point value and obtain one or more
New number range, these number ranges should be considered as specific open herein.
The present invention provides a kind of lithium secondary battery, and the lithium secondary battery includes：Positive pole, negative pole and electrolyte, the negative pole
Negative material include lithium matrix, formed lithium matrix surface lithium metal stratum granulosum and conformal be covered in lithium metal stratum granulosum
The protective layer on surface；
Wherein, the porosity of the lithium metal stratum granulosum is 10-80%；The protective layer contains lithium salts, the lithium salts
Anion is selected from F-、CO3 2-、PO4 3-、TFSI-、FSI-、OH-、SO3 -、R1-COO-With at least one in trifluoromethanesulfonic acid radical ion
Kind, R1For C1-C20Alkyl.
Lithium secondary battery of the present invention be various lithium secondary batteries commonly used in the art, such as lithium metal battery,
Lithium ion battery, lithium-sulfur cell or lithium-air battery, there is no particular limitation to this by the present invention.Those skilled in the art can root
According to specific battery types, suitable electrolyte and positive electrode is selected to be matched.
In the present invention, the lithium matrix is untreated lithium metal commonly used in the art, and it is generally cause
Close structure.Compact texture of the present invention does not produce restriction effect to the lithium matrix of the present invention, is intended merely to lithium matrix and gold
The granuloplastic appearance structure of lithium metal in category lithium stratum granulosum makes a distinction.
In the present invention, the conformal covering refers to that protective layer is covered on lithium metal stratum granulosum, but does not change
Lithium metal stratum granulosum apparent form.
The lithium secondary battery provided according to the present invention, as long as forming lithium metal stratum granulosum on the surface of lithium matrix successively, protecting
Sheath can improve the chemical property of the negative material.The lithium metal stratum granulosum, protective layer are each independent can be to connect
Continuous, or it is discontinuous.Preferably, the lithium metal stratum granulosum, protective layer are continuous, it is highly preferred that this is negative
Pole material includes lithium matrix, is coated on the lithium metal stratum granulosum of lithium matrix surface and is coated on the guarantor of lithium metal particle layer surface
Sheath.
In accordance with the present invention it is preferred that, the porosity of the lithium metal stratum granulosum is 10-80%, it is further preferred that described
The porosity of lithium metal stratum granulosum is 20-60%.
In the present invention, the porosity represents the volume and whole lithium metal stratum granulosum volume of lithium metal stratum granulosum mesopore
Ratio.The porosity can be measured by high power scanning electronic microscope observation combination porosity calculation formula.The hole
Shown in gap rate calculation formula such as formula (1)：
Porosity=(V0-V)/V0× 100% formula (1)
Wherein, V0For the apparent volume of lithium metal stratum granulosum；V is the absolute closely knit volume of lithium metal stratum granulosum.
According to the present invention, the lithium metal stratum granulosum can be interconnected to form by lithium metal particle.
The present invention is wider to the size distribution range of choice of the lithium metal particle, it is preferable that the lithium metal particle
Size distribution is 0.2-20 μm, and more preferably 0.5-15 μm, be still more preferably 1-13 μm.When lithium metal particle is average
During undersized, the side reaction intensity between the two is increased while electrolyte and the increase of electrode contact area, is formed thicker
SEI films, reduce battery coulombic efficiency；When lithium metal average particle size is excessive so that electrode surface roughness, lithium metal particle point
Cloth is uneven, is unfavorable for effectively reducing surface current density.
In the present invention, the size distribution is obtained by high power scanning electronic microscope observation.
A preferred embodiment of the invention, the thickness of the lithium metal stratum granulosum is 300-1500 μm, preferably
For 500-1300 μm.When lithium metal stratum granulosum is blocked up, the side reaction between excessive specific surface area increase electrode and electrolyte, no
Beneficial to the increase of the coulombic efficiency of battery；When lithium metal stratum granulosum is relatively thin, the wellability between reduction electrode and electrolyte is unfavorable
In lithium ion interface migration.
In the present invention, the thickness of the lithium metal stratum granulosum is obtained by high power scanning electronic microscope observation.
A preferred embodiment of the invention, the lithium metal particle of the lithium metal stratum granulosum is in bulk.It is described
Bulk can be rule can also be it is irregular, the present invention to this, there is no particular limitation.Preferably, the bulk includes
Water chestnut square block and/or rectangular-shape.The metal of the lithium metal stratum granulosum of the negative material of the lithium secondary battery i.e. of the invention provided
Lithium particle can be in regular rectangular-shape, water chestnut square block, irregular rectangular-shape and the irregular water chestnut square of rule
At least one of shape.The lithium metal particle that the present invention provides the lithium metal stratum granulosum of the negative material of lithium secondary battery is presented
Pattern can by SEM observation obtain, as shown in Figure 1.
In accordance with the present invention it is preferred that, the lithium salts is faintly acid lithium salts, i.e., it is in weak acid that the anion of described lithium salts, which is preferably,
Property anion, it is further preferred that the anion of the faintly acid salt be selected from F-、CO3 2-、PO4 3-、TFSI-、FSI-、OH-、
SO3 -、R1-COO-At least one of with trifluoromethanesulfonic acid radical ion, R1For C1-C4Alkyl.
A preferred embodiment of the invention, the anion of the lithium salts is selected from F-、CO3 2-、CH3COO-With
TFSI-At least one of.
A preferred embodiment of the invention, the protective layer contains LiF, Li2CO3、Li3PO4、LiTFSI、
LiFSI、R1- COOLi and Li2SO3At least one of, more preferably LiF, CH3COOLi, LiTFSI and Li2CO3In
At least one, is still more preferably LiF.It is more beneficial for avoiding Li dendrite using the protective layer for preferably comprising LiF of the present invention
Generation.
A preferred embodiment of the invention, on the basis of the gross weight of protective layer, lithium salts in the protective layer
Content be 100 weight %.
In the present invention, the content of lithium salts can be carried out really by EDX energy spectrum analysis and XPS analysis in the protective layer
It is fixed.
In accordance with the present invention it is preferred that, the specific surface area of the protective layer is 0.56-56m2/ g, more preferably 1-
12m2/g.The specific surface area is measured by BET specific surface area method of testing.
The lithium secondary battery provided according to the present invention, its negative material is formd with uniform cap layer in lithium matrix surface
The micron grade blocky lithium metal stratum granulosum of cladding, can increase the contact area of cathode of lithium and electrolyte, be more beneficial for lithium ion
In the migration of negative terminal surface, more avtive spots are provided for the deposition of lithium ion, interface impedance is significantly reduced；Reduction
Surface current density promotes the uniform arrangement of negative terminal surface electric charge effectively to suppress the generation of Li dendrite.Negative material
Lithium metal particle deposits the presence with that can stablize during dissolving in lithium, effectively promotes being stabilized for SEI films.Cause
This, can solve the problem that the growth of Li dendrite and derivative safety problem, can effectively improve the chemical property of lithium secondary battery.
There is no particular limitation for preparation method of the present invention to the negative material of above-mentioned lithium secondary battery anode, as long as can
The method for preparing above-mentioned negative material is used equally for the present invention, it is preferable that the preparation side of the negative material of the negative pole
Method includes：Under an inert atmosphere, by lithium matrix and pretreatment fluid haptoreaction, the pretreatment fluid contains faintly acid salt, described
The cation of faintly acid salt is selected from [NH4H]2+、[NH4]+[BMIm]+[HMIm]+At least one of, the faintly acid salt
Anion is selected from F-、CO3 2-、PO4 3-、TFSI-、FSI-、OH-、SO3 -、R1-COO-With at least one in trifluoromethanesulfonic acid radical ion
Kind, R1For C1-C20Alkyl.
A preferred embodiment of the invention, on the basis of the gross weight of the pretreatment fluid, the faintly acid
The content of salt is 0.002-0.1 weight %, more preferably preferably 0.005-0.08 weight %, 0.04-0.08 weight %.
It is easily broken to metallic lithium surface excessive corrosion when pretreatment fluid excessive concentration, it can be adjusted by suitably shortening the reaction time
Section.
Also contain solvent in the pretreatment fluid, the present invention is wider to the range of choice of the solvent, as long as connect with lithium
The solvent not reacted when tactile with lithium is used equally for the present invention, it is preferable that the solvent is organic polar solvent, further excellent
Selection of land, the solvent is selected from tetrahydrofuran (THF), dimethyl sulfoxide (DMSO) (DMSO), acetonitrile, dimethyl imide (DMF) and N- first
At least one of base pyrrolidones, it is further preferred that the solvent is dimethyl sulfoxide (DMSO) and/or dimethyl imide,
Most preferably, the solvent is dimethyl sulfoxide (DMSO).
There is no particular limitation to the preparation of the pretreatment fluid by the present invention, for example, the pretreatment fluid is by by weak acid
Property salt is stirred with solvent to be obtained, and the stirring is carried out under an inert atmosphere.
The lithium secondary battery provided according to the present invention, it is preferable that the condition of the stirring includes：Temperature is 20-30 DEG C, when
Between be 5-10h, mixing speed is 500-1200r/min, it is further preferred that temperature be 25-30 DEG C.
The lithium secondary battery provided according to the present invention, the faintly acid salt reacts with lithium metal, and the generation present invention is above-mentioned
Faintly acid lithium salts, the selection of the anion is as described above, will not be repeated here.
The lithium secondary battery provided according to the present invention, preferably described lithium matrix is the lithium metal for eliminating surface passivation layer
Piece.
A preferred embodiment of the invention, the faintly acid salt be selected from ammonium acid fluoride, ammonium fluoride, ammonium acetate,
At least one of [BMIm] TFSI and [HMIm] TFSI, it is further preferred that the faintly acid salt is ammonium acid fluoride and/or fluorine
Change ammonium, most preferably ammonium acid fluoride.Ammonium acid fluoride generates the protective layer containing LiF, the guarantor containing LiF with lithium metal haptoreaction
Sheath is more beneficial for avoiding the generation of Li dendrite.In addition, from ammonium acid fluoride and/or ammonium fluoride (preferably ammonium acid fluoride), reaction
Thing is relatively simple, ammonium ion is stayed in a solvent, it is to avoid the introducing of impurity in negative material.
In the present invention, as long as by lithium matrix and pretreatment fluid haptoreaction, to the catalytic specific reality
Applying mode, there is no particular limitation, for example, lithium matrix can be immersed in pretreatment fluid, can also be sprayed at pretreatment fluid
Lithium matrix surface.
The lithium secondary battery provided according to the present invention, it is preferable that the catalytic condition includes：Temperature is 20-50
DEG C, the time is 2-48h, it is preferable that temperature is 20-30 DEG C, and the time is 8-36h, it is further preferred that temperature is 25-30 DEG C, when
Between be 18-24h.
The lithium secondary battery provided according to the present invention, it is preferable that the haptoreaction is carried out under agitation, stirring
Speed is 500-1200r/min.
The present invention to the inert atmosphere, there is no particular limitation, for example, the inert atmosphere can by helium, argon gas and
At least one of neon is provided, and is preferably provided by argon gas.
The lithium secondary battery provided according to the present invention, it is preferable that this method also includes to consolidating that the haptoreaction is obtained
Body material is dried.There is no particular limitation for condition of the present invention to the drying, and the drying can be (excellent in inert gas
Elect argon gas as) carry out under circulation condition, the temperature of the drying can be 20-40 DEG C, be carried out preferably at 25-30 DEG C.To institute
State the flow velocity of inert gas and there is no particular limitation time of drying, as long as by the unnecessary pretreatment fluid of solid matter surface
Drying is removed.Those skilled in the art can suitably be selected as the case may be.
According to a kind of most preferred embodiment of the present invention, the preparation method of the negative material of the negative pole includes：
(1) under an inert atmosphere, ammonium acid fluoride and/or ammonium fluoride (being preferably ammonium acid fluoride) are stirred with solvent,
Obtain pretreatment fluid, the pretreatment fluid, on the basis of the gross weight of the pretreatment fluid, the ammonium acid fluoride and/or fluorination
The content of ammonium (preferably ammonium acid fluoride) is 0.04-0.08 weight %；
(2) by lithium matrix and pretreatment fluid haptoreaction, the catalytic condition includes：Temperature is 25-30 DEG C, when
Between be 18-24h.
Using the above-mentioned preferred embodiment of the present invention, being more beneficial for being formed on lithium matrix has special surface structure
(lithium metal stratum granulosum), and ammonium acid fluoride and/or ammonium fluoride and lithium reaction, can contain in the formation of lithium metal particle layer surface
The protective layer of lithium fluoride, the micron grade blocky lithium metal stratum granulosum energy coated with uniform cap layer is formd in lithium matrix surface
The contact area of enough further increase cathode of lithium and electrolyte, it is lithium ion to be more beneficial for lithium ion in the migration of negative terminal surface
Deposition provides more avtive spots, significantly reduces interface impedance.The lithium metal particle of negative material lithium deposit with it is molten
The presence that can stablize during solution, more effectively promotes being stabilized for SEI films.Therefore, the negative material obtained can
The growth of Li dendrite and derivative safety problem are solved, the chemical property of lithium secondary battery can be further effectively improved.
According to the present invention, there is no particular limitation to the positive pole by the present invention, can be the conventional selection in this area, example
Such as, the positive pole can be in intercalation compounds positive electrode, metal oxide, air, sulphur and S-containing composite
It is at least one.
The intercalation compounds positive electrode can be selected from cobalt acid lithium, lithium nickelate, layered lithium manganate, and ternary material (contains
At least one of Ni, Co, Mn, Al and related proportioning) and lithium-rich manganese-based anode material；Wherein, the ternary material can be
Three kinds of the ternary material in Ni, Co, Mn and Al, the present invention is not in ternary material, the mol ratio of each metal is made especially
Restriction, ternary material commonly used in the art is within range of choice of the present invention.
The metal oxide includes but is not limited to barium oxide or manganese dioxide；The barium oxide can be selected from V2O4、
V2O3And V2O5At least one of.
The S-containing composite can be molybdenum disulfide and/or sulphur carbon composite.
There is no particular limitation to the electrolyte by the present invention, in the lithium secondary battery that the present invention is provided, as long as including institute
The negative material stated has preferable chemical property, and various electrolyte commonly used in the art are used equally for the present invention.
For example, the electrolyte can contain solvent and LiTFSI, LiPF6Or LiFSI.Addition can also be contained in the electrolyte
Agent LiNO3, at least one of LiODFB and LiF.But the present inventor has found in research process, using containing
LiTFSI and the electrolyte of film forming are used cooperatively with above-mentioned negative material, and lithium secondary battery chemical property is more preferable.It is therefore preferable that
Ground, the electrolyte contains LiTFSI, film for additive and solvent.
The present invention is wider to the range of choice of the molar concentration of the LiTFSI, it is preferable that the LiTFSI's is mole dense
Spend for 0.5-1mol/L, more preferably 0.5-0.8mol/L.
A preferred embodiment of the invention, the mol ratio of the LiTFSI and film for additive are 1-4:1.Adopt
It is more beneficial for improving the cyclical stability and coulomb of lithium secondary battery with the preferred LiTFSI and film for additive mol ratio
Efficiency.
The present invention is wider to the range of choice of the species of the film for additive, for example, the film for additive can be selected
From LiNO3, vinylene carbonate, at least one of fluorinated ethylene carbonate and ethylene sulfite, more preferably
LiNO3.Using the preferably film for additive and LiNO3Use cooperatively, be more beneficial for improving the electrochemistry of lithium secondary battery
Energy.
The present invention is wider to the range of choice of the solvent, for example, can be that volume ratio is 1:1 DME (glycol dinitrates
Ether)/DOL (1,3- dioxolanes).
A preferred embodiment of the invention, the lithium secondary battery can also include barrier film, wherein, barrier film
Effect is to avoid both positive and negative polarity from directly contacting to cause battery short circuit.The selection and installation of barrier film of the present invention can be according to this areas
Conventional technical means is carried out, for example, the barrier film can be at least one in PP films, PE films, PP/PE films and PP/PE/PP films
Plant, preferably the porous polypropylene barrier films of Celgard@2400.
The present invention will be described in detail by way of examples below.
In the examples below, the ESEM used when electron microscopic observation and EDX analyses is scanned to sweep for Flied emission
Retouch Electronic Speculum (Hitachi Hitachi S-4800)；
Battery assembling is carried out using MBraun Labmaster130 argon gas gloves for protections case；
LAND CT2001A testers are purchased from Wuhan Lan electricity Electronics Co., Ltd.s；
Magnetic stirring apparatus is Germany's IKA topolino magnetic stirring apparatus；
Battery diaphragm is the porous polypropylene barrier films of Celgard@2400.
The specific surface area of cell negative electrode material is measured using BET specific surface area method of testing.
The porosity of the lithium metal stratum granulosum of lithium anode material is used to observe under high power SEM and combined
Porosity calculation formula is obtained.
XPS analysis use scanning zone X ray detecting photoelectron spectrograph (PHI QUANTERA-II SXM).
Embodiment 1
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
(1) preparation of negative material
A) under high-purity argon gas (99.999 volume %, commercially available) atmosphere, by 0.08g ammonium acid fluorides and 10g dimethyl sulfoxide (DMSO)s
(purity is more than 99.9 weight %) mixing, in stirring 8h at 25 DEG C, mixing speed is 800r/min, obtains pretreatment fluid；
B) lithium piece for eliminating surface passivation layer is immersed in pretreatment fluid, in (800r/min) under stirring condition, in
24h is reacted at 25 DEG C；
C) the solid matter taking-up obtained by step b) is reacted, (flow velocity of argon gas is 2.5L/ under argon gas circulation condition
Min), 2h is dried at 25 DEG C, obtain lithium anode material S1.
SEM and XRD test analysis is carried out to lithium anode material S1, as a result respectively as depicted in figs. 1 and 2.From SEM knots
As can be seen that lithium anode material S1 lithium matrix surface forms by rule and irregular water chestnut square block micron in fruit
The lithium metal stratum granulosum that grade particles are formed by connecting, the thickness for measuring lithium metal stratum granulosum from SEM sectional view is 1000 μm, from
SEM it can be seen from the figure thats, the size distribution of lithium metal particle is 3-13 μm.From XRD spectra as can be seen that lithium anode material
S1 is LiF diffraction maximum occur at 65.5 ° in 2 θ, it was demonstrated that the protective layer contains LiF.
EDX and XPS analysis are carried out to lithium anode material S1 surfaces, XPS results show lithium anode material S1's
Surface-element is F and Li, and because the relative atomic mass of Li elements is smaller, the signal of generation is weaker, so analyzing nothing by EDX
Method is detected whether containing Li elements, and the peak only in XPS figures with a LiF is can be seen that by XPS analysis result (Fig. 3),
And simple substance Li peak is not contained, and then can be determined that protective layer is LiF from EDX, XRD and XPS Comprehensive analysis results.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.
(2) assembling of lithium secondary battery
Using lithium anode material S1 as negative pole, 0.6mol/L LiTFSI and 0.4mol/L LiNO are used3's
(DME and DOL volume ratio are 1 to DME/DOL solution:1) it is as electrolyte, sulphur, Super P (conductive agent) and binding agent is poly- inclined
(5 weight % Kynoar solution, trade mark U.S. Su Wei 1015, producer's Dongguan City gold ships plastic material to PVF PVDF
Company) compare 7 according to weight:2:1 mixing, obtains positive pole coating material smear on aluminium foil and positive plate is made, battery diaphragm is
The porous polypropylene barrier films of Celgard 2400, are assembled into model CR2025 experiment buttons in the glove box full of argon gas atmosphere
Battery B1.
Constant current charge and discharge performance test is carried out on LAND CT2001A testers, charging or discharging current density is 0.2mAcm-2。
Coulombic efficiency and the coulombic efficiency that is averaged for 100 weeks after all coulombic efficiencies of head of above-mentioned battery, circulation 100 weeks are detected respectively, are used to
Evaluate stability of the lithium ion in electrode surface deposition/peeling.Coulombic efficiency can illustrate lithium ion after circulation in higher 100 weeks
The growth that would be even more beneficial to suppress Li dendrite of being uniformly distributed on metal lithium electrode surface, the cycle life of battery is longer.As a result
It is listed in table 1.
Embodiment 2
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
(1) preparation of negative material
A) under high-purity argon gas (99.999 volume %, commercially available) atmosphere, by 0.04g ammonium acid fluorides and 10g dimethyl sulfoxide (DMSO)s
(purity is more than 99.9 weight %) mixing, in stirring 8h at 25 DEG C, mixing speed is 800r/min, obtains pretreatment fluid；
B) lithium piece for eliminating surface passivation layer is immersed in pretreatment fluid, in (800r/min) under stirring condition, in
18h is reacted at 30 DEG C；
C) the solid matter taking-up obtained by step b) is reacted, (flow velocity of argon gas is 2.5L/ under argon gas circulation condition
Min), 2h is dried at 25 DEG C, obtain lithium anode material S2.
SEM and XRD test analysis is carried out to lithium anode material S2.As can be seen that lithium anode from SEM results
Material S2 lithium matrix surface forms the lithium metal that by rule and irregular water chestnut square block micron particles are formed by connecting
Stratum granulosum, the thickness that lithium metal stratum granulosum is measured from SEM sectional view is 880 μm, from SEM it can be seen from the figure thats, lithium metal
The size distribution of grain is 1-10 μm.From XRD spectra as can be seen that lithium anode material S2 is to occur LiF's at 65.5 ° in 2 θ
Diffraction maximum, it was demonstrated that the protective layer contains LiF.
EDX and XPS analysis are carried out to lithium anode material S2 surfaces, XPS results show lithium anode material S2's
Surface-element is F and Li, and because the relative atomic mass of Li elements is smaller, the signal of generation is weaker, so analyzing nothing by EDX
Method is detected whether containing Li elements, and the peak only in XPS figures with a LiF is can be seen that by XPS analysis result, without
Peak containing simple substance Li, and then can be determined that protective layer is LiF from EDX, XRD and XPS Comprehensive analysis results.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.
(2) assembling of lithium secondary battery
Using lithium anode material S2 as negative pole, 0.8mol/L LiTFSI and 0.2mol/L LiNO are used3's
(DME and DOL volume ratio are 1 to DME/DOL solution:1) as electrolyte, sulphur and Super P (conductive agent) are compared 8 with weight:2
It is well mixed, flowed down in high-purity argon gas (99.999 volume %, commercially available), 150 DEG C of firing obtain sulphur carbon composite for 12 hours, general
Sulphur carbon composite, Super P (conductive agent) and binding agent Kynoar PVDF (5 weight % Kynoar solution, board
Number U.S. Su Wei 1015, producer's Dongguan City gold ships plastic material company) compare 7 according to weight:2:1 mixing, obtains positive pole coating
Positive plate is made in material smear on aluminium foil, and battery diaphragm is the porous polypropylene barrier films of Celgard@2400, full of argon gas gas
Model CR2025 experiment button cells B2 is assembled into the glove box of atmosphere.Button cell B2 electrochemical property test is with implementation
Example 1, is as a result listed in table 1.
Embodiment 3
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
(1) preparation of negative material
A) under high-purity argon gas (99.999 volume %, commercially available) atmosphere, by 0.07g ammonium acid fluorides and 10g dimethyl sulfoxide (DMSO)s
(purity is more than 99.9 weight %) mixing, in stirring 8h at 25 DEG C, mixing speed is 800r/min, obtains pretreatment fluid；
B) lithium piece for eliminating surface passivation layer is immersed in pretreatment fluid, in (800r/min) under stirring condition, in
20h is reacted at 28 DEG C；
C) the solid matter taking-up obtained by step b) is reacted, (flow velocity of argon gas is 2.5L/ under argon gas circulation condition
Min), 2h is dried at 25 DEG C, obtain lithium anode material S3.
SEM and XRD test analysis is carried out to lithium anode material S3.As can be seen that lithium anode from SEM results
Material S3 lithium matrix surface forms the lithium metal that by rule and irregular water chestnut square block micron particles are formed by connecting
Stratum granulosum, the thickness that lithium metal stratum granulosum is measured from SEM sectional view is 960 μm, from SEM it can be seen from the figure thats, lithium metal
The size distribution of grain is 1-10 μm.From XRD spectra as can be seen that lithium anode material S3 is to occur LiF's at 65.5 ° in 2 θ
Diffraction maximum, it was demonstrated that the protective layer contains LiF.
EDX and XPS analysis are carried out to lithium anode material S3 surfaces, XPS results show lithium anode material S3's
Surface-element is F and Li, and because the relative atomic mass of Li elements is smaller, the signal of generation is weaker, so analyzing nothing by EDX
Method is detected whether containing Li elements, and the peak only in XPS figures with a LiF is can be seen that by XPS analysis result, without
Peak containing simple substance Li, and then can be determined that protective layer is LiF from EDX, XRD and XPS Comprehensive analysis results.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.
(2) assembling of lithium secondary battery
Using lithium anode material S3 as negative pole, 0.5mol/L LiTFSI and 0.5mol/L LiNO are used3's
(DME and DOL volume ratio are 1 to DME/DOL solution:1) as electrolyte, sulphur and Super P (conductive agent) are compared 8 with weight:2
It is well mixed, flowed down in high-purity argon gas (99.999 volume %, commercially available), 150 DEG C of firing obtain sulphur carbon composite for 12 hours, general
Sulphur carbon composite, Super P (conductive agent) and binding agent Kynoar PVDF (5 weight % Kynoar solution, board
Number U.S. Su Wei 1015, producer's Dongguan City gold ships plastic material company) compare 7 according to weight:2:1 mixing, obtains positive pole coating
Positive plate is made in material smear on aluminium foil, and battery diaphragm is the porous polypropylene barrier films of Celgard@2400, full of argon gas gas
Model CR2025 experiment button cells B3 is assembled into the glove box of atmosphere.Button cell B3 electrochemical property test is with implementation
Example 1, is as a result listed in table 1.
Embodiment 4
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
According to the method for embodiment 1, unlike, in step b), the time of reaction is 12h, obtains lithium anode material
Expect S4.Model CR2025 experiment button cells B4 is obtained by follow-up assembling.
SEM and XRD test analysis is carried out to lithium anode material S4.As can be seen that lithium anode from SEM results
Material S4 lithium matrix surface forms the lithium metal that by rule and irregular water chestnut square block micron particles are formed by connecting
Stratum granulosum, the thickness that lithium metal stratum granulosum is measured from SEM sectional view is 750 μm, from SEM it can be seen from the figure thats, lithium metal
The size distribution of grain is 2-15 μm.From XRD spectra as can be seen that lithium anode material S4 is to occur LiF's at 65.5 ° in 2 θ
Diffraction maximum, it was demonstrated that the protective layer contains LiF.
EDX and XPS analysis are carried out to lithium anode material S4 surfaces, XPS results show lithium anode material S4's
Surface-element is F and Li, and because the relative atomic mass of Li elements is smaller, the signal of generation is weaker, so analyzing nothing by EDX
Method is detected whether containing Li elements, and the peak only in XPS figures with a LiF is can be seen that by XPS analysis result, without
Peak containing simple substance Li, and then can be determined that protective layer is LiF from EDX, XRD and XPS Comprehensive analysis results.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.Button cell B4 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Embodiment 5
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
According to the method for embodiment 1, unlike, in step b), the time of reaction is 48h, obtains lithium anode material
Expect S5.Model CR2025 experiment button cells B5 is obtained by follow-up assembling.
SEM and XRD test analysis is carried out to lithium anode material S5.As can be seen that lithium anode from SEM results
Material S5 lithium matrix surface forms the lithium metal that by rule and irregular water chestnut square block micron particles are formed by connecting
Stratum granulosum, the thickness that lithium metal stratum granulosum is measured from SEM sectional view is 1260 μm, from SEM it can be seen from the figure thats, lithium metal
The size distribution of grain is 2-6 μm.From XRD spectra as can be seen that lithium anode material S5 is to occur LiF's at 65.5 ° in 2 θ
Diffraction maximum, it was demonstrated that the protective layer contains LiF.
EDX and XPS analysis are carried out to lithium anode material S5 surfaces, XPS results show lithium anode material S5's
Surface-element is F and Li, and because the relative atomic mass of Li elements is smaller, the signal of generation is weaker, so analyzing nothing by EDX
Method is detected whether containing Li elements, and the peak only in XPS figures with a LiF is can be seen that by XPS analysis result, without
Peak containing simple substance Li, and then can be determined that protective layer is LiF from EDX, XRD and XPS Comprehensive analysis results.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.Button cell B5 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Embodiment 6
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
According to the method for embodiment 1, unlike, ammonium acid fluoride is replaced using [BMIm] TFSI of phase homogenous quantities, obtained
Lithium anode material S6.Model CR2025 experiment button cells B6 is obtained by follow-up assembling.
SEM and XRD test analysis is carried out to lithium anode material S6.As can be seen that lithium anode from SEM results
Material S6 lithium matrix surface forms the lithium metal that by rule and irregular water chestnut square block micron particles are formed by connecting
Stratum granulosum, the thickness that lithium metal stratum granulosum is measured from SEM sectional view is 660 μm, from SEM it can be seen from the figure thats, lithium metal
The size distribution of grain is 0.2-12 μm.From XRD spectra as can be seen that lithium anode material S6 is 33 ° or so appearance in 2 θ
LiTFSI diffraction maximum, it was demonstrated that the protective layer contains LiTFSI.
EDX and XPS analysis are carried out to lithium anode material S6 surfaces, XPS results show lithium anode material S6's
Surface-element is Li, C, N and S, and because the relative atomic mass of Li elements is smaller, the signal of generation is weaker, so passing through EDX points
Analysis can not be detected whether containing Li elements, and be can be seen that by XPS analysis result in XPS figures only with LiTFSI
Peak, and simple substance Li peak is not contained, and then can be determined that protective layer is LiTFSI from EDX, XRD and XPS Comprehensive analysis results.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.Button cell B6 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Embodiment 7
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
According to the method for embodiment 1, unlike, ammonium acid fluoride is replaced using [HMIm] TFSI of phase homogenous quantities, obtained
Lithium anode material S7.Model CR2025 experiment button cells B7 is obtained by follow-up assembling.
SEM and XRD test analysis is carried out to lithium anode material S7.As can be seen that lithium anode from SEM results
Material S7 lithium matrix surface forms the lithium metal that by rule and irregular water chestnut square block micron particles are formed by connecting
Stratum granulosum, the thickness that lithium metal stratum granulosum is measured from SEM sectional view is 590 μm, from SEM it can be seen from the figure thats, lithium metal
The size distribution of grain is 0.2-13 μm.From XRD spectra as can be seen that lithium anode material S7 occurs from 2 θ are 33 ° or so
LiTFSI diffraction maximum, it was demonstrated that the protective layer contains LiTFSI.
EDX and XPS analysis are carried out to lithium anode material S7 surfaces, XPS results show lithium anode material S7's
Surface-element is Li, C, N and S, and because the relative atomic mass of Li elements is smaller, the signal of generation is weaker, so passing through EDX points
Analysis can not be detected whether containing Li elements, and be can be seen that by XPS analysis result in XPS figures only with LiTFSI
Peak, and simple substance Li peak is not contained, and then can be determined that protective layer is LiTFSI from EDX, XRD and XPS Comprehensive analysis results.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.Button cell B7 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Embodiment 8
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
According to the method for embodiment 1, unlike, ammonium acid fluoride is replaced using the ammonium carbonate of phase homogenous quantities, metal is obtained
Lithium titanate cathode material S8.Model CR2025 experiment button cells B8 is obtained by follow-up assembling.
SEM and XRD test analysis is carried out to lithium anode material S8.As can be seen that lithium anode from SEM results
Material S8 lithium matrix surface forms the lithium metal that by rule and irregular water chestnut square block micron particles are formed by connecting
Stratum granulosum, the thickness that lithium metal stratum granulosum is measured from SEM sectional view is 880 μm, from SEM it can be seen from the figure thats, lithium metal
The size distribution of grain is 0.3-12 μm.From XRD spectra as can be seen that lithium anode material S8 is 31.8 ° or so appearance in 2 θ
Li2CO3Diffraction maximum, it was demonstrated that the protective layer contains Li2CO3。
EDX and XPS analysis are carried out to lithium anode material S8 surfaces, XPS results show lithium anode material S8's
Surface-element is Li, C and O, and because the relative atomic mass of Li elements is smaller, the signal of generation is weaker, so being analyzed by EDX
It can not detect whether containing Li elements, and can be seen that by XPS analysis result only has a Li in XPS figures2CO3Peak,
And simple substance Li peak is not contained, and then can be determined that protective layer is Li from EDX, XRD and XPS Comprehensive analysis results2CO3。
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.Button cell B8 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Embodiment 9
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
According to the method for embodiment 1, unlike, ammonium acid fluoride is replaced using the ammonium acetate of phase homogenous quantities, metal is obtained
Lithium titanate cathode material S9.Model CR2025 experiment button cells B9 is obtained by follow-up assembling.
SEM and XRD test analysis is carried out to lithium anode material S9.As can be seen that lithium anode from SEM results
Material S9 lithium matrix surface forms the lithium metal that by rule and irregular water chestnut square block micron particles are formed by connecting
Stratum granulosum, the thickness that lithium metal stratum granulosum is measured from SEM sectional view is 850 μm, from SEM it can be seen from the figure thats, lithium metal
The size distribution of grain is 0.2-15 μm.From XRD spectra as can be seen that lithium anode material S9 is 23.4 ° or so appearance in 2 θ
CH3COOLi diffraction maximum, it was demonstrated that the protective layer contains CH3COOLi。
EDX and XPS analysis are carried out to lithium anode material S9 surfaces, XPS results show lithium anode material S9's
Surface-element is Li, H, C and O, and because the relative atomic mass of H, Li element is smaller, the signal of generation is weaker, so passing through EDX
Analysis can not be detected whether containing H, Li element, and can be seen that by XPS analysis result only has one in XPS figures
CH3COOLi peak, and simple substance Li peak is not contained, and then can be determined that protection from EDX, XRD and XPS Comprehensive analysis results
Layer is CH3COOLi。
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.Button cell B9 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Embodiment 10
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
According to the method for embodiment 1, unlike, the consumption of ammonium acid fluoride is 0.1g, obtains lithium anode material
S10.Model CR2025 experiment button cells B10 is obtained by follow-up assembling.
SEM and XRD test analysis is carried out to lithium anode material S10.As can be seen that lithium metal is born from SEM results
Pole material S10 lithium matrix surface forms the metal that by rule and irregular water chestnut square block micron particles are formed by connecting
Lithium stratum granulosum, the thickness that lithium metal stratum granulosum is measured from SEM sectional view is 1050 μm, from SEM it can be seen from the figure thats, lithium metal
The size distribution of particle is 0.3-10 μm.From XRD spectra as can be seen that lithium anode material S10 is to occur at 65.5 ° in 2 θ
LiF diffraction maximum, it was demonstrated that the protective layer contains LiF.
EDX and XPS analysis are carried out to lithium anode material S10 surfaces, XPS results show lithium anode material S10
Surface-element be F and Li, because the relative atomic mass of Li elements is smaller, the signal of generation is weaker, so being analyzed by EDX
It can not detect whether containing Li elements, and the peak only in XPS figures with a LiF is can be seen that by XPS analysis result, and
Simple substance Li peak is not contained, and then can be determined that protective layer is LiF from EDX, XRD and XPS Comprehensive analysis results.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.Button cell B10 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Comparative example 1
According to the method for embodiment 1, unlike, without using ammonium acid fluoride, it will directly eliminate the lithium of surface passivation layer
Piece is immersed in dimethyl sulfoxide (DMSO), specifically：
The lithium piece for eliminating surface passivation layer is immersed in 10g dimethyl sulfoxide (DMSO)s, in (800r/min) under stirring condition,
In contacting 24h at 25 DEG C；
Solid matter obtained by contact is taken out, (flow velocity of argon gas is 2.5L/min), 25 DEG C under argon gas circulation condition
Lower drying 2h, obtains lithium anode material D1.Model CR2025 experiment button cells DB1 is obtained by follow-up assembling.
SEM test analysis is carried out to lithium anode material D1, as shown in figure 4, as can be seen that metal from SEM results
Lithium titanate cathode material D1 lithium matrix surface is without the phenomenon being etched.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.Button cell DB1 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Comparative example 2
According to the method for embodiment 1, unlike, without using ammonium acid fluoride, it will directly eliminate the lithium of surface passivation layer
Piece, which is immersed in, to be diluted in the HF that concentration is 0.04%, specifically：
The lithium piece for eliminating surface passivation layer is immersed in the HF that 10g concentration is 0.04%, under stirring condition
(800r/min), in contacting 24h at 25 DEG C；
Solid matter obtained by contact is taken out, (flow velocity of argon gas is 2.5L/min), 25 DEG C under argon gas circulation condition
Lower drying 2h, obtains lithium anode material D2.Model CR2025 experiment button cells DB2 is obtained by follow-up assembling.
The porosity of the lithium metal stratum granulosum of lithium anode material and the specific surface area test of lithium anode material
It the results are shown in Table 1.Button cell DB2 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Embodiment 11
The present embodiment is used for the lithium secondary battery for illustrating that the present invention is provided.
According to the method for embodiment 1, unlike, without using LiNO in electrolyte3, i.e., with 0.6mol/L LiTFSI's
(DME and DOL volume ratio are 1 to DME/DOL solution:1) as electrolyte, model CR2025 experiment button cells are assembled into
B11.Button cell B11 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Embodiment 12
According to the method for embodiment 1, unlike, with 1mol/L LiPF6EC (vinyl carbonate)/DMC (carbonic acid two
Methyl esters) (EC, DMC, EMC volume ratio are 1 to/EMC (methyl ethyl carbonate) solution:1:1) it is electrolyte, is assembled into model
CR2025 experiment button cells B12.Button cell B12 electrochemical property test be the same as Example 1, is as a result listed in table 1.
Table 1
By embodiment 1-12 and comparative example 1-2 comparing result, button is assembled using the modification lithium piece of the present invention
The all coulombic efficiencies of higher head are shown after battery, illustrate the lithium salts protective layer tool on the modified metal lithium sheet surface of the present invention
There is very high stability.Circulate after 100 weeks, the lithium secondary battery that the present invention is provided has higher average coulombic efficiency, says
It is bright that more stable SEI films are formd during circulating battery by modified metal lithium sheet, be conducive to lithium ion in lithium metal
Negative terminal surface is uniformly distributed, so the modification lithium secondary battery cathode material that the present invention is used can suppress the production of Li dendrite
It is raw, improve the lithium secondary battery cyclical stability that the present invention is provided, and extend the cycle life of lithium secondary battery and carry
The coulombic efficiency of high battery.In addition, the preparation for the lithium secondary battery cathode material that the present invention is provided will not produce pollution gas
And liquid, inert atmosphere will not be destroyed, processing method environmental protection, technique is simple to operation, and cost is low；And the present invention is provided
Lithium secondary battery anode can be processed in batches, with good prospects for commercial application.
The preferred embodiment of the present invention is described in detail above in association with accompanying drawing, still, the present invention is not limited to above-mentioned reality
The detail in mode is applied, in the range of the technology design of the present invention, a variety of letters can be carried out to technical scheme
Monotropic type, these simple variants belong to protection scope of the present invention.
It is further to note that each particular technique feature described in above-mentioned embodiment, in not lance
In the case of shield, can be combined by any suitable means, in order to avoid unnecessary repetition, the present invention to it is various can
The combination of energy no longer separately illustrates.
In addition, various embodiments of the present invention can be combined randomly, as long as it is without prejudice to originally
The thought of invention, it should equally be considered as content disclosed in this invention.
Claims (10)
1. a kind of lithium secondary battery, it is characterised in that the lithium secondary battery includes：Positive pole, negative pole and electrolyte, the negative pole
Negative material include lithium matrix, formed lithium matrix surface lithium metal stratum granulosum and conformal be covered in lithium metal stratum granulosum table
The protective layer in face；
Wherein, the porosity of the lithium metal stratum granulosum is 10-80%；The protective layer contains lithium salts, the lithium salts it is cloudy from
Son is selected from F-、CO3 2-、PO4 3-、TFSI-、FSI-、OH-、SO3 -、R1-COO-At least one of with trifluoromethanesulfonic acid radical ion, R1
For C1-C20Alkyl.
2. lithium secondary battery according to claim 1, wherein, the porosity of the lithium metal stratum granulosum is 10-80%；
Preferably, the lithium metal stratum granulosum is interconnected to form by lithium metal particle, the size distribution of the lithium metal particle
For 0.2-20 μm, preferably 0.5-15 μm, more preferably 1-13 μm；
Preferably, the thickness of the lithium metal stratum granulosum is 300-1500 μm, preferably 500-1300 μm.
3. lithium secondary battery according to claim 1 or 2, wherein, the lithium metal particle of the lithium metal stratum granulosum is in rule
Then or irregular bulk, it is preferable that described block to include water chestnut square block and/or rectangular-shape.
4. the lithium secondary battery according to any one in claim 1-3, wherein,
The protective layer contains LiF, Li2CO3、Li3PO4、LiTFSI、LiFSI、R1- COOLi and Li2SO3At least one of, it is excellent
Elect LiF as；
Preferably, on the basis of the gross weight of protective layer, the content of lithium salts is 100 weight % in the protective layer.
5. the lithium secondary battery according to any one in claim 1-4, wherein, the preparation of the negative material of the negative pole
Method includes：
Under an inert atmosphere, by lithium matrix and pretreatment fluid haptoreaction, the pretreatment fluid contains faintly acid salt, the weak acid
Property salt cation be selected from [NH4H]2+、[NH4]+[BMIm]+[HMIm]+At least one of, the faintly acid salt it is cloudy from
Son is selected from F-、CO3 2-、PO4 3-、TFSI-、FSI-、OH-、SO3 -、R1-COO-At least one of with trifluoromethanesulfonic acid radical ion, R1
For C1-C20Alkyl；
Preferably, on the basis of the gross weight of the pretreatment fluid, the content of the faintly acid salt is 0.002-0.1 weight %,
Preferably 0.005-0.08 weight %, more preferably 0.04-0.08 weight %；
The pretreatment fluid also contains solvent, it is preferable that the solvent is organic polar solvent, it is further preferred that described molten
Agent is selected from least one of tetrahydrofuran, dimethyl sulfoxide (DMSO), acetonitrile, dimethyl imide and 1-METHYLPYRROLIDONE, more enters
Preferably, the solvent is dimethyl sulfoxide (DMSO) and/or dimethyl imide to one step；
Preferably, the pretreatment fluid is obtained by the way that faintly acid salt is stirred with solvent, and the stirring is under an inert atmosphere
Carry out；
Preferably, the condition of the stirring includes：Temperature is 20-30 DEG C, and the time is 5-10h, and mixing speed is 500-1200r/
min。
6. lithium secondary battery according to claim 5, wherein, the faintly acid salt is selected from ammonium acid fluoride, ammonium fluoride, acetic acid
At least one of ammonium, [BMIm] TFSI and [HMIm] TFSI.
7. the lithium secondary battery according to claim 5 or 6, wherein, lithium matrix is included with pretreatment fluid haptoreaction：Will
Lithium matrix is immersed in pretreatment fluid, or pretreatment fluid is sprayed at into lithium matrix surface；
Preferably, the catalytic condition includes：Temperature is 20-50 DEG C, and the time is 2-48h, it is further preferred that temperature
For 20-30 DEG C, the time is 8-36h, it is further preferred that temperature is 25-30 DEG C, the time is 18-24h.
8. the lithium secondary battery according to any one in claim 1-7, wherein, the positive pole is selected from intercalation compounds
At least one of positive electrode, metal oxide, air, sulphur and S-containing composite；
Preferably, the intercalation compounds positive electrode is selected from cobalt acid lithium, lithium nickelate, layered lithium manganate, tertiary cathode material
At least one of with lithium-rich manganese-based anode material；
Preferably, the metal oxide is selected from barium oxide or manganese dioxide；
Preferably, the S-containing composite is molybdenum disulfide and/or sulphur carbon composite.
9. the lithium secondary battery according to any one in claim 1-8, wherein, the electrolyte contain LiTFSI, into
Film additive and solvent；
Preferably, the molar concentration of the LiTFSI is 0.5-1mol/L；
Preferably, the mol ratio of the LiTFSI and film for additive are 1-4:1.
10. lithium secondary battery according to claim 9, wherein,
The film for additive is selected from LiNO3, vinylene carbonate, in fluorinated ethylene carbonate and ethylene sulfite at least
One kind, more preferably LiNO3；
The solvent is that volume ratio is 1:1 DME/DOL.
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| CN109524708A (en) * | 2018-09-11 | 2019-03-26 | 湖南立方新能源科技有限责任公司 | High-energy-density flexible-package metal lithium battery |
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