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
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—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
  • H01M10/0568—Liquid materials characterised by the solutes
• • 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
  • H01M10/0569—Liquid materials characterised by the solvents
• • 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
• • 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
  • H01M2300/0028—Organic electrolyte characterised by the solvent
• • 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

Definitions

• the present disclosure relates to electrolyte solutions for electrochemical cells.
• an electrolyte solution includes a solvent; an electrolyte salt; and a LA:LB complex represented by the following general formula I:
• A is boron or phosphorous
• F is fluorine
• L is an aprotic organic amine
• x is an integer from 1-3, and at least one N atom of the aprotic organic amine, L, is bonded directly to A.
• the LA:LB complex is present in the solution in an amount of between 0.01 and 5.0 wt.%, based on the total weight of the electrolyte solution.
• a method of making an electrolyte solution includes combining a solvent, an electrolyte salt, and a LA:LB complex.
• the LA:LB complex is represented by the following general formula (I) :
• A is boron or phosphorous
• F is fluorine
• L is an aprotic organic amine
• x is an integer from 1-3, and at least one N atom of the aprotic organic amine, L, is bonded directly to A.
• the LA:LB complex is present in the solution in an amount of between 0.01 and 5.0 wt.%, based on the total weight of the electrolyte solution.
• an electrochemical cell is provided.
• the electrochemical cell includes a positive electrode, a negative electrode, and an electrolyte solution as described above.
• an electrolyte solution includes a solvent; an electrolyte salt; and a LA:LB complex represented by the following general formula I:
• A is boron or phosphorous
• F is fluorine
• L is an aprotic heteroaromatic amine
• x is an integer from 1-3, and at least one N atom of the aprotic heteroaromatic amine, L, is bonded directly to A.
• the LA:LB complex is present in the solution in an amount of between 0.01 and 5.0 wt.%, based on the total
• Figure 1 shows a schematic cross sectional view of an exemplary lithium ion electrochemical cell.
• Figure 2 shows the capacity versus cycle number curves for Graphite/NMCl 11 cells cycled at 55°C between 2.8-4.2V at 80mA..
• Figure 3 shows the capacity versus cycle number curves for Graphite/NMC442 cells cycled at 55°C between 2.8-4.4V at 80mA.
• Electrolyte additives designed to selectively react with, bond to, or self-organize at the electrode surface in a way that passivates the interface represents one of the simplest and potentially most cost effective ways of achieving this goal.
• the effect of common electrolyte solvents and additives, such as ethylene carbonate (EC), vinylene carbonate (VC), 2-fluoroethylene carbonate (FEC), and lithium bisoxalatoborate (LiBOB) on the stability of the negative electrode SEI (solid-electrolyte interface) layer is well documented.
• electrolyte additives that are capable of further improving the high temperature performance and stability (e.g. > 55°C) of lithium ion cells, provide electrolyte stability at high voltages (e.g. > 4.2V) for increased energy density, and enable the use of high voltage electrodes.
• stoichiometric LA:LB complex means a complex in which its component elements are present in substantially the exact proportions indicated by the formula of the complex.
• aprotic organic amine means an organic compound that includes nitrogen, and in which there are no hydrogen atoms directly bound to nitrogen or directly bound to other heteroatoms (such as O and S) that may optionally be present in the compound.
• all numbers expressing quantities or ingredients, measurement of properties and so forth used in the specification and embodiments are to be understood as being modified in all instances by the term "about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached listing of embodiments can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings of the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claimed embodiments, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
• the present disclosure in some embodiments, relates to a class of Lewis acid : Lewis base (LA:LB) complexes that can act as performance enhancing additives to the electrolytes of electrochemical cells (e.g., lithium ion electrochemical cells).
• LA:LB Lewis base
• These complexes can provide performance benefits in electrochemical cells when used at relatively low loadings in the electrolyte (e.g., ⁇ 5 wt% of the total electrolyte solution).
• electrochemical cells having electrolytes that include the LA:LB complexes of the present disclosure may exhibit improved high temperature storage performance, improved coulombic efficiency, improved charge endpoint capacity slippage, less impedance growth, reduced gas generation and improved charge-discharge cycling.
• the LA:LB complexes of the present disclosure may display relatively high stability in ambient air, thus providing improved ease of handling and improved safety vs. known LA:LB complexes (e.g., BF 3 - diethyl ether and BF 3 -dimethyl carbonate, which rapidly hydrolyze in air to produce a visible white smoke (due to FIF formation)).
• the unexpected efficacy of the present LA:LB complexes at low loadings can lead to a reduction in overall electrolyte additive cost per electrochemical cell. Indeed, reduction in material costs is an important factor in the adoption of lithium-ion battery technology in new applications (e.g., electric vehicles, renewable energy storage).
• the present disclosure relates to electrolyte solutions for electrochemical cells.
• the electrolyte solutions may include a solvent, one or more salts, and one or more LA:LB complexes.
• the electrolyte solutions may include one or more solvents.
• the solvent may include one or more organic carbonates. Examples of suitable solvents include ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, vinylene carbonate, propylene carbonate,
• organic polymer containing electrolyte solvents which can include solid polymer electrolytes or gel polymer electrolytes, may also be employed.
• Organic polymers may include polyethylene oxide, polypropylene oxide, ethylene oxide/propylene oxide copolymers, polyacrylonitrile, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymers, and poly- [bis((methoxyethoxy)ethoxy)phosphazene] (MEEP), or combinations thereof.
• the solvents may be present in the electrolyte solution in an amount of between 15 and 98 wt.%, 25 and 95 wt.%, 50 and 90 wt.%, or 70 and 90 wt.%, based on the total weight of the electrolyte solution.
• the electrolyte solution may include one or more electrolyte salts.
• the electrolyte salts may include lithium salts and, optionally, other salts such as sodium salts (e.g., NaPF 6 ).
• Suitable lithium salts may include LiPF 6 , L1BF4, L1CIO4, lithium bis(oxalato)borate, LiN(S0 2 CF 3 ) 2 , LiN(S0 2 C 2 F 5 )2, LiAsFe, LiC(S0 2 CF 3 ) 3 , LiN(S0 2 F) 2 , LiN(S0 2 F)(S0 2 CF 3 ), LiN(S02F)(S0 2 C4F 9 ), or combinations thereof.
• the lithium salts may include LiPF 6 , lithium
• the lithium salts may include LiPF 6 and either or both of lithium bis(oxalato)borate and LiN(SC"2CF 3 )2.
• the salts may be present in the electrolyte solution in an amount of between 2 and 85 wt%, 5 and 75 wt%, 10 and 50 wt%, or 10 and 30 wt%, based on the total weight of the electrolyte solution.
• the electrolyte solutions may include one or more LA:LB complexes.
• the LA:LB complexes may have the following formula (I):
• A is boron or phosphorous
• F is fluorine
• L is an aprotic organic amine
• the LA:LB complex may be a stoichiometric LA:LB complex (i.e., very little, if any, excess (or uncomplexed) Lewis acid or Lewis base may be present in the electrolyte).
• excess Lewis acid or Lewis base may be present in the electrolyte solution at less than 10 mol%, less than 5 mol%, less than 3 mol%, or less than 1 mol%, based on the stoichiometry indicated in the LA:LB complex structural formula(s).
• the Lewis acid and Lewis base components of the LA:LB complex may be bonded together via a dipolar, co-ordinate (or dative) covalent bond formed by donation of a lone (or non-bonding) electron pair on at least one N atom of the Lewis base to the empty (or unoccupied) orbital on the B or P atom of the Lewis acid (BF 3 or PFs, respectively).
• the LA:LB complex may be held together by at least one B-N or P-N bond and at least one N atom of the aprotic organic amine, L, is bonded directly to A in formula (I)
• the aprotic organic amine (L) in formula (I) may include at least one N atom with a non-bonding electron pair that is available for bonding with an empty orbital of the Lewis acid (FnA).
• the aprotic organic amines may include tertiary amines that may be cyclic or acyclic, saturated or unsaturated, substituted or unsubstituted, and may optionally contain other catenary heteroatoms, such as O, S, and N, in the carbon chain or ring.
• the aprotic organic amines may include heteroaromatic amines that may be substituted or unsubstituted and may optionally contain other catenary heteroatoms, such as O, S, and N, in the carbon chain or ring.
• suitable tertiary amines may include trimethylamine, triethylamine, tributylamine, tripentylamine, trihexylamine, trioctylamine, N,N- diisopropylethylamine, benzyldimethylamine, triphenylamine, N,N-diethylmethylamine, N-methylpiperidine, N-ethylpiperidine, l-chloro-N,N-dimethyl-methanamine, N-ethyl-N- (methoxymethyl)-ethanamine, N-methylpyrrolidine, N-ethylpyrrolidine, N- propylpyrrolidine, N-butyllpyrrolidine, l,8-diazabicycloundec-7-ene, 1,5- diazabicyclo[4.3.0]non-5-ene, 7-methyl-l,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,4- diazabic
• suitable heteroaromatic amines may include pyridine, pyrazine, pyridazine, pyrimidine, 4-dimethylaminopyridine, 1-methylimidizole, 1- methylpyrazole, thiazole, oxazole, all isomers thereof and substituted variants thereof wherein the substituent groups can include either H; F; nitrile groups; separate alkyl or fluoroalkyl groups from 1 to 4 carbon atoms, respectively or joined together to constitute a unitary alkylene radical of 2 to 4 carbon atoms forming a ring structure; alkoxy or fluoroalkoxy groups; or separate aryl of fluoroaryl groups.
• the LA:LB complexes may be selected from:
• the LA:LB complex or complexes may be present in the electrolyte solution in an amount of between 0.01 and 40.0 wt.%, 0.01 and 20.0 wt.%, 0.01 and 10.0 wt.%, 0.01 and 5.0 wt.%, 0.1 and 5.0 wt.%, or 0.5 and 5.0 wt.% based on the total weight of the electrolyte solution.
• the electrolyte solutions of the present disclosure may include one or more conventional electrolyte additives such as, for example, vinylene carbonate (VC), fluoroethylene carbonate (FEC), propane-1,3- sultone (PS), prop- 1-ene- 1,3 -sultone (PES), succinonitrile (SN), l,5,2,4-dioxadithiane-2,2,4,4-tetraoxide (MMDS), lithium bis(oxalate)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), tris(trimethylsilyl)phosphite (TTSPi), ethylene sulfite (ES), l,3,2-dioxathiolan-2,2-oxide (DTD), vinyl ethylene carbonate(VEC), trimethylene sulfite (TMS), tri-allyl-phosphate (TAP), methyl phenyl carbonate (MP
• the present disclosure is further directed to electrochemical cells (e.g., lithium-ion electrochemical cells as shown in Figure 1) that include the above- described electrolyte solutions.
• the electrochemical cells may include at least one positive electrode, at least one negative electrode, and a separator.
• the positive electrode may include a current collector having disposed thereon a positive electrode composition.
• the current collector for the positive electrode may be formed of a conductive material such as a metal.
• the current collector includes aluminum or an aluminum alloy.
• the thickness of the current collector is 5 ⁇ to 75 ⁇ . It should also be noted that while the positive current collector may be described as being a thin foil material, the positive current collector may have any of a variety of other configurations according to various exemplary embodiments.
• the positive current collector may be a grid such as a mesh grid, an expanded metal grid, a
• the positive electrode composition may include an active material.
• the active material may include a lithium metal oxide or lithium metal phosphate.
• the active material may include lithium transition metal oxide intercalation compounds such as L1C0O2, LiCoo.2Nio.8O2, LiMmC ⁇ , LiFePC"4, LiNi02, or lithium mixed metal oxides of manganese, nickel, and cobalt in any proportion. Blends of these materials can also be used in positive electrode compositions.
• Other exemplary cathode materials are disclosed in U.S. Patent No. 6,680,145 (Obrovac et al.) and include transition metal grains in combination with lithium-containing grains.
• Suitable transition metal grains include, for example, iron, cobalt, chromium, nickel, vanadium, manganese, copper, zinc, zirconium, molybdenum, niobium, or combinations thereof with a grain size no greater than about 50 nanometers.
• Suitable lithium-containing grains can be selected from lithium oxides, lithium sulfides, lithium halides (e.g., chlorides, bromides, iodides, or fluorides), or combinations thereof.
• the positive electrode composition may further include additives such as binders (e.g., polymeric binders (e.g., polyvinylidene fluoride)), conductive diluents (e.g., carbon), fillers, adhesion promoters, thickening agents for coating viscosity modification such as
• carboxymethylcellulose or other additives known by those skilled in the art.
• the positive electrode composition can be provided on only one side of the positive current collector or it may be provided or coated on both sides of the current collector.
• the thickness of the positive electrode composition may be 0.1 ⁇ to 3 mm, 10 ⁇ to 300 ⁇ , or 20 ⁇ to 90 ⁇ .
• the negative electrode may include a current collector and a negative electrode composition disposed on the current collector.
• the current collector of the negative electrode may be formed of a conductive material such as a metal.
• the current collector includes copper or a copper alloy, titanium or a titanium alloy, nickel or a nickel alloy, or aluminum or an aluminum alloy.
• the thickness of the current collector may be 5 ⁇ to 75 ⁇ . It should also be noted that while the current collector of the negative electrode may be described as being a thin foil material, the current collector may have any of a variety of other configurations according to various exemplary embodiments.
• the current collector of the negative electrode may be a grid such as a mesh grid, an expanded metal grid, a photochemically etched grid, or the like.
• the negative electrode composition may include an active material (e.g., a material that is capable of intercalating or alloying with lithium.)
• the active material may include lithium metal, carbonaceous materials, or metal alloys (e.g., silicon alloy composition or lithium alloy compositions).
• Suitable carbonaceous materials can include synthetic graphites such as mesocarbon microbeads (MCMB) (available from China Steel, Taiwan, China ) , SLP30 (available from TimCal Ltd., Bodio Switzerland), natural graphites and hard carbons.
• Suitable alloys may include electrochemically active components such as silicon, tin, aluminum, gallium, indium, lead, bismuth, and zinc and may also include electrochemically inactive components such as iron, cobalt, transition metal silicides and transition metal aluminides.
• the active material of the negative electrode includes a silicon alloy.
• the negative electrode composition may further include additives such as binders (e.g., polymeric binders (e.g., polyvinylidene fluoride or styrene butadiene rubber (SBR)), conductive diluents (e.g., carbon black and/or carbon
• nanotubes fillers, adhesion promoters, thickening agents for coating viscosity
• the negative electrode composition can be provided on only one side of the negative current collector or it may be provided or coated on both sides of the current collector.
• the thickness of the negative electrode composition may be 0.1 ⁇ to 3 mm, 10 ⁇ to 300 ⁇ , or 20 ⁇ to 90 ⁇ .
• the electrochemical cells of the present disclosure may include a separator (e.g., a polymeric microporous separator which may or may not be coated with a layer of inorganic particles such as AI2O3) provided intermediate or between the positive electrode and the negative electrode.
• a separator e.g., a polymeric microporous separator which may or may not be coated with a layer of inorganic particles such as AI2O3
• the electrodes may be provided as relatively flat or planar plates or may be wrapped or wound in a spiral or other
• the electrodes may be wrapped around a relatively rectangular mandrel such that they form an oval wound coil for insertion into a relatively prismatic battery case.
• the electrodes may be wrapped around a relatively rectangular mandrel such that they form an oval wound coil for insertion into a relatively prismatic battery case.
• the battery may be provided as a button cell battery, a thin film solid state battery, or as another lithium ion battery configuration.
• the separator can be a polymeric material such as a polypropylene/polyethylene copolymer or another polyolefin multilayer laminate that includes micropores formed therein to allow electrolyte and lithium ions to flow from one side of the separator to the other.
• the thickness of the separator may be between approximately 10 micrometers ( ⁇ ) and 50 ⁇ according to an exemplary embodiment.
• the average pore size of the separator may be between approximately 0.02 ⁇ and 0.1 ⁇ .
• the present disclosure is further directed to electronic devices that include the above-described electrochemical cells.
• the disclosed electrochemical cells can be used in a variety of devices including, without limitation, portable computers, tablet displays, personal digital assistants, mobile telephones, motorized devices (e.g., personal or household appliances and vehicles), power tools, illumination devices, and heating devices.
• the present disclosure further relates to methods of making an electrochemical cell.
• the method may include providing the above-described negative electrode, providing the above-described positive electrode, and incorporating the negative electrode and the positive electrode into a battery comprising the above-described electrolyte solution.
• EMC Ethyl Methyl Carbonate
• DMC Dimethyl Carbonate
• reaction flask equipped with N2 sidearm
• anhydrous pyridine (2.94g, 0.0372mol) was charged.
• the reaction flask was capped and placed under an inert atmosphere (N2, He or Ar) and cooled in an ice bath near 0°C.
• Boron trifluoride diethyl etherate (4.602g, 0.0324mol) was added to the pyridine via syringe under inert atmosphere. Solids precipitated as the boron trifluoride diethyl etherate was added to the reaction mixture. After all of the boron trifluoride diethyl etherate was charged, the reaction mixture was cooled to -20°C in a freezer overnight to promote crystal growth.
• the reaction was vacuum stripped of diethyl ether and excess pyridine using a high vacuum line while the product was heated to 45°C before transferring to a nitrogen glove box for storage.
• the appearance of the solid product ranged from colorless to pale yellow amorphous to crystalline solids.
• the mass yield of the isolated product was used to confirm the synthesis of the desired material. Furthermore, the identity of the product was confirmed by 3 ⁇ 4 and 19 F MR spectroscopy.
• reaction flask equipped with N2 sidearm
• anhydrous 2,6-lutidine (3.54g, 0.0330mol) and diethyl ether (14.16g, 0.1667mol) were charged.
• the reaction flask was capped and placed under an inert atmosphere (N2, He or Ar) and cooled in an ice bath to 0°C.
• Boron trifluoride diethyl etherate (4.602g, 0.0324mol) was added to the amine solution via syringe under inert atmosphere. Solids precipitated as the boron trifluoride diethyl etherate was added to the reaction mixture.
• reaction flask equipped with N2 sidearm
• pyrazine (3.54g, 0.0330mol)
• diethyl ether (10.08g, 0.1360mol)
• the reaction flask was capped and placed under an inert atmosphere (N2, He or Ar) and cooled in an ice bath to 0°C.
• Boron trifluoride diethyl etherate (9.20g, 0.0648mol) was added to the amine solution via syringe under inert atmosphere. Solids precipitated as the boron trifluoride diethyl etherate was added to the reaction mixture.
• the reaction mixture was cooled to -20°C in a freezer overnight to promote crystal growth. The following morning the supernatant of the reaction mixture was removed via syringe. The solid product was washed twice under inert atmosphere with lOmL aliquots of anhydrous diethyl ether before it was vacuum stripped of diethyl ether using a high vacuum line while the product was heated to 45°C before transferring to a nitrogen glove box for storage. The appearance of the product ranged from colorless to pale yellow amorphous to crystalline solids. The mass yield of the isolated product was used to confirm synthesis of the desired 2: 1 BF 3 :pyrazine complex.
• reaction flask equipped with N2 sidearm
• anhydrous 1-methylimidizole (2.71g, 0.033 lmol) and diethyl ether (7.13g, 0.0962mol) were charged.
• the reaction flask was capped and placed under an inert atmosphere (N2, He or Ar) and cooled in an ice bath to 0°C.
• Boron trifluoride diethyl etherate (4.60g, 0.0324mol) was added to the amine solution via syringe under inert atmosphere. Solids precipitated as the boron trifluoride diethyl etherate was added to the reaction mixture.
• reaction flask equipped with N2 sidearm
• anhydrous l,8-Diazabicycloundec-7-ene (5.03g, 0.0330mol) and diethyl ether (7.13g, 0.0946mol) were charged.
• the reaction flask was capped and placed under an inert atmosphere (N2, He or Ar) and cooled in an ice bath to 0°C.
• Boron trifluoride diethyl etherate (4.602g, 0.0324mol) was added to the amine solution via syringe under inert atmosphere. Solids precipitated as the boron trifluoride diethyl etherate was added to the reaction mixture.
• Pyridine (12.56g, 0.1588mmol) was charged to the oven dried body of a Parr reactor. Following addition of the pyridine, the reactor was fully assembled, sealed, and then cooled in a dry ice bath. Once cool, vacuum was pulled on the contents of the reactor using a water aspirator vacuum pump. The contents of the reactor were stirred as they were allowed to warm to room temperature. Then, phosphorus pentafluoride gas (lO.OOg, 0.7939mmol) was charged to the evacuated reactor at room temperature via reinforced pressure tubing. The temperature within the reactor spiked to 53°C during addition of PFs, indicating that an exothermic reaction had occurred. The reaction mixture was stirred overnight at room temperature.
• VC vinylene carbonate
• PES prop- 1-ene- 1,3- sultone
• TEP triallyl phosphate
• EDTD ethylene sulfate [l,3,2-dioxathiolane-2,2-dioxane (DTD)] BF3 :diethyl ether (BFE) and BF3 : dimethyl carbonate (BFC).
• Dry Li[Nio.33Mno.33Coo.33]02 (NMCl 1 l)/graphite pouch cells (240 mAh), dry Li[Nio.42Mno.42Coo.i6]02 (NMC442)/graphite pouch cells (240 mAh), and LifNio.5Mno.3Coo.2jO2 (NMC532)/graphite pouch cells (220 mAh) were obtained without electrolyte from Li-Fun Technology Corporation (Xinma Industry Zone, Golden Dragon Road, Tianyuan District, Zhuzhou City, Hunan province, PRC, 412000, China).
• the positive electrode coating had a thickness of 105 ⁇ and was calendared to a density of 3.55 g/cm 3 .
• the negative electrode coating had a thickness of 110 ⁇ and was calendared to a density of 1.55 g/cm 3 .
• the positive electrode coating had an areal density of 16 mg/cm 2 and the negative electrode had an areal density of 9.5 mg/cm 2 .
• the positive electrode dimensions were 200 mm x 26 mm and the negative electrode dimensions were 204 mm x 28 mm. Both electrodes were coated on both sides, except for small regions on one side at the end of the foils.
• cells were placed in a temperature box at 40.0 ⁇ 0.1°C where they were held at 1.5 V for 24 hours, to allow for the completion of wetting. Then, cells were charged at 11 mA (C/20) to 3.8 V. After this step, cells were transferred and moved into the glove box, cut open to release gas generated and then vacuum sealed again. After degassing, impedance spectra of the cells were measured at 3.8 V as described below.
• the NMC/graphite cells destined for 4.5V operation were degassed a second time at 4.5 V. The amounts of gas created during formation to 3.8 V and between 3.8 V and 4.5 V were measured and recorded for NMC111 and NMC442. The amount of gas created during formation to 3.5 V and between 3.5 V and 4.5 V was measured and recorded for NMC532 cells.
• the cells were cycled using the Ultra High Precision Charger (UHPC) at Dalhousie
• Electrochemical Storage Test Protocol The cycling/storage procedure used in these tests is described as follows. Cells were first charged to 4.4 or 4.5 V and discharged to 2.8 V two times. Then the cells were charged to 4.4 or 4.5 V at a current of C/20 (11 mA) and then held at 4.4 or 4.5 V until the measured current decreased to C/1000. A Maccor series 4000 cycler was used for the preparation of the cells prior to storage. After the pre-cycling process, cells were carefully moved to the storage system which monitored their open circuit voltage every 6 hours.
• the open circuit voltage of Li-ion pouch cells was measured before and after storage at either 60°C for 350 hours or 40°C for 500 hours.
• the voltage drop (AV) is described in the equation 1.
• NMC/Graphite pouch cells before and after storage. Cells were charged or discharged to 3.80 V before they were moved to a 10.0 ⁇ 0.1 °C temperature box.
• AC impedance spectra were collected with ten points per decade from 100 kHz to 10 mHz with a signal amplitude of 10 mV at 10.0 ⁇ 0.1°C.
• the impedance rise (ohms) recorded in Table 3 was calculated according to the following equation:
• ⁇ -situ (static) gas measurements were used to measure gas evolution during formation and during cycling. The measurements were made using Archimedes' principle with cells suspended from a balance while submerged in liquid. The changes in the weight of the cell suspended in fluid, before and after testing are directly related to the change in cell volume due to the impact on buoyant force.
• the change in mass of a cell, Am, suspended in a fluid of density, p, is related to the change in cell volume, ⁇ , by
• Ex-situ measurements were made by suspending pouch cells from a fine wire "hook” attached under a Shimadzu balance (AUW200D).
• the pouch cells were immersed in a beaker of de-ionized “nanopure” water (18.2 ⁇ -cm) that was at 20 ⁇ 1°C for measurement.
• Example 21 2% Phosphorus Pentafluoride Pyridine (1 : 1) Lithium ion pouch cells containing the MC442 cathode and graphite anode were stored at 4.4V and at 60°C, as described above. The voltage drop, impedance rise, and gas evolution results are summarized in Table 3. The data clearly indicates that electrolyte containing Lewis acid:Lewis base complexes of the invention as electrolyte additives reduce voltage drop, impedance rise and gas generation upon storage at high temperature and high voltage.
• Lithium ion pouch cells containing the MC442 cathode and graphite anode were stored at 4.4V and at 40°C, as described above.
• the voltage drop results are summarized in Table 4. The data clearly indicates that electrolyte containing Lewis acid:Lewis base complexes of the invention as electrolyte additives reduce voltage drop, impedance rise and gas generation upon storage at high temperature and high voltage.
• Table 5 shows ultra-high precision cycling data for MC442/graphite pouch cells cycled at 40°C and 4.4V. Electrolyte containing the additives disclosed in this invention provide comparable or better performance with respect to coulombic efficiency (CE), charge endpoint capacity slippage, gas volume change, and charge transfer impedance rise compared to comparative example 2 (with 2% VC additive).
• CE coulombic efficiency
• Example 13 0.9977 0.36 0.05 0.41 MC442/graphite pouch cells were cycled at 55°C and 4.4V. Table 6 shows the capacity retention, impedance rise, and cell volume increase on long term cycling test. Obviously all the cells with additives disclosed in this invention showed better cycling performance than the comparative example 8 (with 2% TAP additive).
• Lithium ion pouch cells containing the MC442 cathode and graphite anode were stored at 4.5V and at 40°C, as described above.
• the voltage drop results are summarized in Table 7 and clearly show that electrolyte containing Lewis acid:Lewis base complexes of the invention as electrolyte additives improved the cell's storage performance at high temperature and high voltage.
• Example 1 0.16 0.28 -0.002
• Example 2 0.15 0.13 -0.003
• Figure 2 shows the discharge capacity of MC111/graphite cells vs. cycle number during extended testing ( ⁇ 6 months) at 55°C. In order to clearly compare the curves, the capacities of the cells were normalized to the same starting value (210mAh). The actual capacities were in the range of 205 to 217mAh. The cells with control electrolyte lost more than 20% of their initial capacity in the first 200 cycles.
• Figure 2 clearly shows that example 2 significantly improved cycle life of lithium ion cells compared to comparative examples 1, and 2.
• MC442/graphite cells were cycled between 2.8 and 4.4 V at 55°C.
• Figure 3 shows the discharge capacity versus cycle number of MC442/graphite pouch cells containing different additives under extremely aggressive cycling conditions.
• the cells were cycled between 2.8 V and 4.4 V at 55°C and 80 raA current ( ⁇ rate C/3) without clamps, so generated gas would promote loss of stack pressure. After 500 cycles (more than 4 months), all of these cells retained less than 80% of their initial capacity but example 14 performed best. Cells with additives disclosed in this invention showed promising long-term cycling results at high voltage (4.4V) and high temperature (55°C) vs. comparative example 8 (with 2% TAP additive).
• Lithium ion pouch cells containing the MC532 cathode and graphite anode were stored at 4.5V and at 60°C, as described above.
• the voltage drop results are summarized in Table 8 and clearly show that electrolyte containing Lewis acid:Lewis base complex of the invention as electrolyte additives improved the cell's storage performance at high temperature and high voltage. The amount of gas generated under these storage conditions were also greatly reduced.
• Table 8 MC532/Graphite Cell Performance Metrics upon Storage at 60°C and
• Dry pouch cells (200 mAh) were obtained without electrolyte from Li-Fun Technology Corporation (Xinma Industry Zone, Golden Dragon Road, Tianyuan District, Zhuzhou City, Hunan province, PRC, 412000, China).
• the positive electrode coating had a thickness of 93 ⁇ .
• the negative electrode coating had thickness of 44 ⁇ , a loading of 6.6 mg/cm 2 and was calendered to 30% porosity.
• the positive electrode dimensions were 187 mm x 26 mm and the negative electrode dimensions were 191 mm x 28 mm. These cells are referred to as LiFunSi-vl
• Both electrodes were coated on both sides, except for small regions on one side at the end of the foils. All pouch cells were vacuum sealed without electrolyte in China. Before electrolyte filling, the cells were cut just below the heat seal and dried at 80°C under vacuum for at least 14 h to remove any residual water in a dry room with a dew point of - 40 °C. While still in the dry room, the cells were filled with electrolyte and vacuum sealed. All pouches were filled with 0.65 mL of electrolyte. After filling, cells were vacuum-sealed with a vacuum sealer (MSK-115 A, MTI Corp.).
• the LiFunSi-vl cells were cycled with a Neware BTS4000 cycler in a temperature controlled room at 22 ⁇ 2 °C. After the formation cycle described above the cells were charged a 100 mA (C/2) up to 4.35 V and held at 4.35 V until the current dropped to 10 mA (C/20), left to rest open circuit for 15 minutes, then discharged at 100 mA (C/2) until the voltage reached 2.75 V, and then left to rest open circuit for 15 minutes. This cycling was repeated and every 50 cycles a slow cycle was performed which consisted in charging at 10 mA (C/20) up to 4.35 V, resting 15 minutes, discharging at 10 mA down to 2.75 V and resting 15 minutes. This cycling procedure was performed for at least 200 cycles. Table 9 lists the additives used in the electrolytes. The electrolytes were formulated using the additive listed, 10% FEC, and the remainder EC/EMC 3/7 with 1M LiPFe.
• the performance of the cells is quantified by the capacity retention after 200 cycles.
• Table 10 lists the performance of the cells and shows that the additives have resulted in improved cycling.
• Table 10 Discharge Retention Data For Si Alloy Cells With Room Temperature Cycling
• the LiFunSi-v2 cells were filled as described above with the electrolytes and additives listed in Table 11 and the remainder EC/EMC 3/7 with 1M LiPF 6 .
• the cells were formed and cycled on an ultra high precision cycler model UHPCvl (Novonix, Suite, NS, Canada) in a temperature controlled chamber held at 45 ⁇ 0.1 °C.
• the cells were cycled by charging at 20 mA (C/10) up to 4.35V, resting open circuit for 15 minutes, discharging at 20 mA down to 2.75 V, and resting open circuit for 15 minutes. At least 40 cycles were performed.
• Table 12 shows the CE, capacity and retention.
• the samples with the Lewis Complex additives show better CE and capacity retention.
• Example 24 32903p2c 0.9966 214.1 192.0 89.7%
• Example 25 32904p2c 0.9965 213.3 190.1 89.1%
• the Lewis Complex additives therefore provide significant benefits in combination with Si alloy materials including increased capacity retention and improved coulombic efficiency. Furthermore added benefits are obtained in combination with fluoroethylene carbonate (FEC), in addition to increased capacity retention and improved coulombic efficiency, the Lewis Complex additives suppress gassing.
• FEC fluoroethylene carbonate
• the dry pouch cells (200 mAh) which were obtained from Li-Fun Technology, referred to as LiFunSi-v2, were used in the Table 13.
• the pouch cells were cut open and dried at 80°C under vacuum for at least 14 h to remove any residual water in a dry room with a dew point of -40 °C. While still in the dry room, the cells were filled with electrolyte and vacuum sealed. All pouches were filled with 0.65 mL of electrolyte. After filling, cells were vacuum-sealed with a vacuum sealer (MSK-115A, MTI Corp.).
• PC Propylene carbonate
• EC Ethylene carbonate
• DEC Diethyl carbonate).
• the pouch cell volume variation before FM1 and post FM1 are the volume of produced gas during FMl (FMl produced Gas). (Detail measurement is described in the section "Determination of Gas Evolution").
• Table 13 The electrolyte type and produced gas volume of Si pouch cell during formation stepl .
• the dry pouch cells (200 mAh) which were obtained from Li-Fun Technology, referred to as LiFunSi-v2 were also used to evaluate the electrolyte in the Table 14. After dried pouch cell were filled with the electrolyte as in Table 14, they were vacuum-sealed with a vacuum sealer (MSK-115A, MTI Corp.). After passing Formation Step 1 (FMl) at room temperature, the cells were sandwiched with two plates under suitable pressure and aged at 70°C for four hours. Then cells were cut open and vacuum-sealed again to remove the produced gas (degassing). Then cells were trickle charge to 4.35V using C/20 current till the current decades down to C/40 at room temperature, then discharge to 2.8V. At last, the cells were degassed and vacuum-sealed again.
• a vacuum sealer MSK-115A, MTI Corp.

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