Flame retardants for battery electrolytes

Abstract

The present invention provides a non-aqueous electrolyte solution for a lithium battery, the non-aqueous electrolyte solution comprising a liquid electrolyte medium, a lithium-containing salt, and at least one oxygen-containing bromine-based flame retardant.

Description

[Technical field]

[0001] The present invention relates to brominated flame retardants for use in battery electrolyte solutions. [Background technology]

[0002] One factor affecting the safety of lithium-ion batteries is the use of flammable solvents in lithium-containing electrolyte solutions. The inclusion of flame retardants in electrolyte solutions is one way to mitigate the flammability of these solutions. For a flame retardant to be a suitable component of an electrolyte solution, in addition to solubility in the electrolyte, it must have electrochemical stability over the battery operating range and minimal adverse effects on battery performance. Adverse effects on battery performance may include reduced conductivity chemical instability to the active material, lithium consumption, and / or formation of resistive interfaces to the active material, which may adversely affect solid electrolyte interface (SEI) formation during initial cycles, resulting in chemical degradation of the electrolyte.

[0003] There is a need for flame retardants that can effectively suppress the flammability of lithium-ion batteries at a reasonable cost while minimizing the impact on the electrochemical performance of the lithium-ion batteries. Summary of the Invention

[0004] The present invention provides non-aqueous electrolyte solutions for lithium batteries that contain at least one oxygen-containing brominated flame retardant. In the presence of the oxygen-containing brominated flame retardant(s), these non-aqueous electrolyte solutions will extinguish a fire, at least under laboratory conditions.

[0005] An embodiment of the present invention is a non-aqueous electrolyte solution for a lithium battery, the solution comprising: i) a liquid electrolyte medium; ii) a lithium-containing salt; and iii) a) a brominated monoester, α) has 3 carbon atoms and at least one bromine atom, or β) a brominated monoester having at least 4 carbon atoms and at least one bromine atom and represented by the following formula: [ka] (In the formula, R 1 and R 2 Each of R has at least one carbon atom; 1 and R 2 at least one of R 2 is a benzyl group and at least one bromine atom is present in the benzyl group, R 1 is a branched or linear alkyl group, and b) a brominated diester having at least 6 carbon atoms and at least one bromine atom and represented by the formula: [ka] (In the formula, R a , R b , and R c Each of R has at least one carbon atom; a , R b , and R c at least one of which has at least one bromine atom; and

[0006] Another embodiment of the present invention is a non-aqueous electrolyte solution for a lithium battery, the solution comprising: i) a liquid electrolyte medium, ii) a lithium-containing salt, and iii) at least one oxygen-containing bromine-based flame retardant, such as methyl bromoacetate, 2-bromoethyl acetate, 4-bromobutyl acetate, 2-bromovinyl acetate, 3-bromoallyl acetate, 3-bromoallyl butyrate, 2,3-dibromoprop-2-en-1-yl acetate, 2,3-dibromoprop-2-en-1-yl propionate, (3,5-dibromophenyl)methyl acetate, 3-bromo-2,2-bis(bromomethyl)propyl acetate, 3-bromo-2-propenoate, methyl 2-bromo-acrylate, 2,3-dibromoprop-2-en-1-yl bromoacetate ... acetate, 2,3-dibromoprop-2-en-1-yl 2-methylpropanoate, (3,5-dibromophenyl)methyl bromoacetate, 2,3-dibromobut-2-ene-1,4-diyl diacetate, 2,3-dibromobut-2-ene-1,4-diyl bis(2-methylpropanoate), 2,3-dibromobut-2-ene-1,4-diyl bis(2-bromobutanoate), 2,2-bis(bromomethyl)-1,3-propanediyl diacetate, and 2,2-bis(bromomethyl)propane-1,3-diyl bis(bromoacetate).

[0007] These and other embodiments and features of the present invention will become further apparent from the following detailed description and the appended claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Throughout this specification, the phrase "electrolyte solution" is used interchangeably with the phrase "nonaqueous electrolyte solution."

[0009] The liquid electrolyte medium is comprised of one or more solvents that typically form the liquid electrolyte medium of the lithium electrolyte solution used in lithium batteries, which are polar, aprotic, stable to electrochemical cycling, and preferably have low viscosity. These solvents typically include acyclic carbonates, cyclic carbonates, ethers, sulfur-containing compounds, and esters of boric acid.

[0010] Solvents which may form the liquid electrolyte medium in the practice of the invention include ethylene carbonate (1,3-dioxolan-2-one), dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dioxolane, dimethoxyethane (glyme), tetrahydrofuran, ethylene sulfite, 1,3-propylene glycol borate, bis(2,2,2-trifluoroethyl) ether, and mixtures of any two or more of the foregoing.

[0011] Preferred solvents include ethylene carbonate, ethyl methyl carbonate, and mixtures thereof. More preferred are mixtures of ethylene carbonate and ethyl methyl carbonate, especially in a volume ratio of about 20:80 to about 40:60, more preferably about 25:75 to about 35:65 ethylene carbonate:ethyl methyl carbonate.

[0012] Lithium-containing salts suitable for the practice of the present invention include lithium perchlorate, lithium nitrate, lithium thiocyanate, lithium aluminate, lithium tetrachloroaluminate, lithium tetrafluoroaluminate, lithium tetraphenylborate, lithium tetrafluoroborate, lithium bis(oxolato)borate (LiBOB), lithium di(fluoro)(oxalato)borate, lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium hexafluoroantimonate, lithium titanate, lithium manganate, lithium cobaltate (LiCoO 2 ), lithium nickel oxide (LiNiO 2), lithium alkylcarbonates in which the alkyl group has 1 to 6 carbon atoms, lithium methylsulfonate, lithium trifluoromethylsulfonate, lithium pentafluoroethylsulfonate, lithium pentafluorophenylsulfonate, lithium fluorosulfonate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(pentafluoroethylsulfonyl)imide, lithium (ethylsulfonyl)(trifluoromethyl-sulfonyl)imide, and mixtures of any two or more of the foregoing. Preferred lithium-containing salts include lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium di(fluoro)(oxolato)borate, and lithium bis(oxolato)borate.

[0013] The usual concentration of the lithium-containing salt in the electrolyte solution is in the range of about 0.1 M to about 2.5 M, preferably about 0.5 M to about 2 M, more preferably about 0.75 M to about 1.75 M, and even more preferably about 0.95 M to about 1.5 M. When a plurality of lithium-containing salts form a lithium-containing electrolyte, the concentration refers to the total concentration of all the lithium-containing salts present in the electrolyte solution.

[0014] The electrolyte solution may contain other salts in addition to lithium salts, provided that such other salt(s) do not substantially degrade either the performance of the battery for the desired application or the flame retardancy of the electrolyte solution. Suitable electrolytes other than lithium salts include other alkali metal salts, such as sodium salts, potassium salts, rubidium salts, and cesium salts, and alkaline earth metal salts, such as magnesium salts, calcium salts, strontium salts, and barium salts. In some embodiments, the only salt in the non-aqueous electrolyte solution is one or more lithium salts.

[0015] Suitable alkali metal salts that may be present in the electrolyte solution include sodium salts such as sodium chloride, sodium bromide, sodium iodide, sodium perchlorate, sodium nitrate, sodium thiocyanate, sodium aluminate, sodium tetrachloroaluminate, sodium tetrafluoroaluminate, sodium tetraphenylborate, sodium tetrafluoroborate, and sodium hexafluorophosphate, and potassium salts such as potassium chloride, potassium bromide, potassium iodide, potassium perchlorate, potassium nitrate, potassium thiocyanate, potassium aluminate, potassium tetrachloroaluminate, potassium tetrafluoroaluminate, potassium tetraphenylborate, potassium tetrafluoroborate, and potassium hexafluorophosphate.

[0016] Suitable alkaline earth metal salts that may be present in the electrolyte solution include magnesium chloride, magnesium bromide, magnesium iodide, magnesium perchlorate, magnesium nitrate, magnesium thiocyanate, magnesium aluminate, magnesium tetrachloroaluminate, magnesium tetrafluoroaluminate, magnesium tetraphenylborate, tetrafluoroaluminate, and magnesium tetrafluoroborate. Included are magnesium salts such as magnesium oroborate and magnesium hexafluorophosphate, and calcium salts such as calcium chloride, calcium bromide, calcium iodide, calcium perchlorate, calcium nitrate, calcium thiocyanate, calcium aluminate, calcium tetrachloroaluminate, calcium tetrafluoroaluminate, calcium tetraphenylborate, calcium tetrafluoroborate, and calcium hexafluorophosphate.

[0017] In the practice of the present invention, the liquid brominated flame retardant is miscible with the liquid medium of the non-aqueous electrolyte solution, where "miscible" means that the brominated flame retardant does not form a separate phase from the electrolyte solution. More specifically, the brominated flame retardant is miscible if it forms a single phase in a mixture of 30% by weight ethylene carbonate and 70% by weight ethyl methyl carbonate containing 1.2M lithium hexafluorophosphate after shaking for 24 hours with a stirring device, no separate phase is formed after shaking is stopped, and the brominated flame retardant does not precipitate from the non-aqueous electrolyte solution or form a suspension or slurry. It is recommended and preferred that the brominated flame retardant does not cause precipitation of any of the other components of the non-aqueous electrolyte solution or the formation of a suspension or slurry.

[0018] In the practice of the present invention, the solid brominated flame retardant is soluble in the liquid medium of the non-aqueous electrolyte solution, where "soluble" means that the brominated flame retardant does not precipitate from the electrolyte solution. More specifically, the brominated flame retardant is soluble if it forms a single phase in a mixture of 30% by weight ethylene carbonate and 70% by weight ethyl methyl carbonate containing 1.2M lithium hexafluorophosphate after shaking for 24 hours with a stirring device, and no separate phase or precipitate is formed after shaking is stopped, and the brominated flame retardant does not precipitate from the non-aqueous electrolyte solution or form a suspension or slurry. It is recommended and preferred that the brominated flame retardant does not cause any of the other components of the non-aqueous electrolyte solution to precipitate or form a suspension or slurry.

[0019] In the practice of the present invention, the oxygen-containing bromine-based flame retardant generally has a bromine content of about 30% by weight or more, preferably about 35% by weight or more, based on the weight of the oxygen-containing bromine-based flame retardant. In the practice of the present invention, the oxygen-containing bromine-based flame retardant has a bromine content in the molecule ranging from about 30% by weight to about 75% by weight, more preferably from about 35% by weight to about 75% by weight.

[0020] The boiling point of the brominated flame retardants of the present invention is about 75° C. or higher, preferably about 95° C. or higher. Generally, the brominated flame retardants used in the practice of the present invention have a boiling point near or above the boiling point of the solvent or solvent mixture of the non-aqueous electrolyte solution. Boiling points discussed throughout this specification are at standard temperature and pressure (standard conditions) unless otherwise specified.

[0021] The brominated flame retardants used in the practice of the present invention are generally polar, aprotic, and stable to electrochemical cycling. Liquid brominated flame retardants also preferably have low viscosity.

[0022] In the practice of the present invention, the amount of flame retardant in the non-aqueous electrolyte solution means that there is enough flame retardant present for the solution to pass the modified horizontal UL-94 test described below. The amount of flame retardant often varies from brominated flame retardant to brominated flame retardant. For the brominated monoesters of the present invention, the amount of flame retardant in the electrolyte solution is usually about 9.5% by weight or more, preferably about 10% by weight or more of bromine (atom) based on the total weight of the non-aqueous electrolyte solution. For the brominated diesters, the amount of flame retardant in the electrolyte solution is usually about 9.5% by weight or more, preferably about 11% by weight or more of bromine (atom) based on the total weight of the non-aqueous electrolyte solution. For both the brominated monoesters and brominated diesters of the present invention, the amount of flame retardant in molecular terms is usually about 20% by weight or more, and in some cases 25% by weight or more, based on the total weight of the non-aqueous electrolyte solution.

[0023] The oxygen-containing brominated flame retardants of the present invention share several general characteristics: they have a bromine content of about 30% or more, preferably about 35% or more, preferably about 30% to about 75% and more preferably about 35% to about 72% by weight based on the total weight of the flame retardant molecule, and the oxygen-containing brominated flame retardant molecule has at least one bromine atom, preferably 1 to 6 bromine atoms.

[0024] In some embodiments, the oxygen-containing brominated flame retardant is a brominated monoester having at least 4 carbon atoms, preferably 4 to about 12 carbon atoms, more preferably 4 to about 10 carbon atoms, and at least 1 bromine atom, preferably 1 to 8 bromine atoms, more preferably 1 to about 6 bromine atoms, and even more preferably 1 to about 4 bromine atoms.

[0025] When the brominated monoester has 4 or more carbon atoms, the brominated monoester can be represented by the formula: [ka] In the formula, R 1 and R 2 Each of R has at least one carbon atom; 1 and R 2 At least one of R has at least one bromine atom. 1 In another embodiment, R 2 In yet another embodiment, R 1 and R 2 Both contain bromine. 1 and / or R 2 In some embodiments where there is only one bromine atom in R, the bromine atom is located at the terminal (ω) carbon atom of the group. 2 In another embodiment, R 1 does not contain a quaternary carbon atom, and preferably R 1 and R 2 None of the groups contain a quaternary carbon atom.

[0026] R 1 In embodiments where R contains bromine, 1 Preferably, R has 1 to about 8 carbon atoms, more preferably 1 to about 4 carbon atoms, and 1 to about 4 bromine atoms, preferably 1 to about 3 bromine atoms, more preferably 1 to about 2 bromine atoms. 1The group may be a branched or straight chain alkyl group, a branched or straight chain alkenyl group, an aryl group, or an aralkyl group, and is preferably a branched or straight chain alkenyl group. 1 Preferred alkenyl groups, when present, include vinyl, allyl, butenyl, pentenyl, and hexenyl, especially vinyl and allyl. 1 contains bromine, R 2 In these embodiments where R does not contain bromine, 2 R preferably has 1 to about 7 carbon atoms, more preferably 1 to about 3 carbon atoms, and may be a branched or straight chain alkyl group, a branched or straight chain alkenyl group, an aryl group, or an aralkyl group, preferably a branched or straight chain alkyl group. 2 Preferred alkyl groups when does not contain bromine include methyl, ethyl, n-propyl, and n-butyl, more preferred are methyl and ethyl, especially methyl.

[0027] R 2 In embodiments where R contains bromine, 2 Preferably, R has 2 to about 8 carbon atoms, more preferably 2 to about 7 carbon atoms, and 1 to about 4 bromine atoms, preferably 1 to about 3 bromine atoms. 2 The group may be a branched or straight chain alkyl group, a branched or straight chain alkenyl group, an aryl group, or an aralkyl group. 2 Preferred groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, neopentyl, vinyl, allyl, butenyl, pentenyl, R includes hexenyl, and benzyl, and more preferably ethyl, n-butyl, neopentyl, vinyl, allyl, and benzyl. 2 contains bromine, R 1 In embodiments where R does not contain bromine, 1R preferably has 1 to about 8 carbon atoms, more preferably 1 to about 6 carbon atoms, and may be a branched or straight chain alkyl group, a branched or straight chain alkenyl group, an aryl group, or an aralkyl group, preferably a branched or straight chain alkyl group. 1 When does not contain bromine, preferred alkyl groups include methyl, ethyl, n-propyl, isobutyl, and n-butyl, more preferred are methyl, ethyl, n-propyl, and isopropyl, especially methyl.

[0028] R 2 is a benzyl group and the benzyl group contains at least one bromine atom, R 1 is a branched or linear alkyl group, optionally and preferably R 1 contains one or more bromine atoms.

[0029] R 1 and R 2 In embodiments where both R 1 R preferably has 1 to about 8 carbon atoms, more preferably 1 to about 4 carbon atoms, and 1 to about 4 bromine atoms, preferably 1 to about 3 bromine atoms, more preferably 1 to about 2 bromine atoms. 1 R may be a branched or straight chain alkyl group, a branched or straight chain alkenyl group, an aryl group, or an aralkyl group, preferably a branched or straight chain alkyl group. Preferred alkyl groups include methyl, ethyl, n-propyl, and n-butyl, more preferably methyl and ethyl, especially methyl. 1 and R 2 When both R and R contain bromine, the preferred bromine-containing R 1 The group is bromomethyl.

[0030] R 1 and R 2 In embodiments where both R 2R has 1 to about 9 carbon atoms, more preferably about 2 to about 8 carbon atoms, and 1 to about 4 bromine atoms, preferably 1 to about 3 bromine atoms, more preferably 1 to about 2 bromine atoms. 2 R may be a branched or straight chain alkyl group, a branched or straight chain alkenyl group, an aryl group, or an aralkyl group, and is preferably a branched or straight chain alkenyl group or an aralkyl group. 2 Preferred groups for R include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, vinyl, allyl, butenyl, pentenyl, hexenyl, and benzyl, more preferably allyl and benzyl. 1 and R 2 When both R and R contain bromine, the preferred bromine-containing R 2 Groups include 2,3-dibromoallyl, (3,5-dibromophenyl)methyl, and (4-bromophenyl)methyl.

[0031] Preferably, the brominated monoester is methyl bromoacetate, 2-bromoethyl acetate; 4-bromobutyl acetate; 2-bromovinyl acetate; 3-bromoallyl acetate; 3-bromoallyl butyrate; 2,3-dibromoprop-2-en-1-yl acetate, also called 2,3-dibromoallyl acetate; 2,3-dibromoprop-2-en-1-yl propanoate, also called 2,3-dibromoallyl propanoate; 2,3-dibromoprop-2-en-1-yl ester; methyl 2-methylpropanoate, (also called 2,3-dibromoprop-2-en-1-yl isobutyrate); (3,5-dibromophenyl)methyl acetate; 3-bromo-2,2-bis(bromomethyl)propyl acetate, (also called tribromoneopentyl acetate); methyl 3-bromo-2-propenoate; methyl 2-bromo-acrylate; 2,3-dibromoprop-2-en-1-yl bromoacetate; or (3,5-dibromophenyl)methyl bromoacetate.

[0032] In some embodiments, the brominated monoester has 3 carbon atoms and at least one bromine atom, preferably 1 to about 4 bromine atoms, and more preferably 1 to about 3 bromine atoms. The brominated monoester having 3 carbon atoms can be represented by the formula above, and as described above, in some embodiments, R 1 contains bromine, and in other embodiments So, R 2 comprises bromine, and in yet other embodiments, R 1 , R 2 In some preferred embodiments, both R 1 is bromomethyl. Preferred brominated monoesters having 3 carbon atoms include methyl bromoacetate.

[0033] In the practice of the present invention, the brominated monoesters preferably have 4 or more carbon atoms.

[0034] In another embodiment, the oxygen-containing brominated flame retardant is a brominated diester having 1 to about 8 bromine atoms, preferably 1 to about 6 bromine atoms, more preferably 2 to about 6 bromine atoms. The brominated diester has about 6 to about 20 carbon atoms, preferably about 6 to about 18 carbon atoms, more preferably about 6 to about 15 carbon atoms. The bromine content of the brominated diester is about 35% by weight or more, preferably about 35% by weight to about 70% by weight, more preferably about 40% by weight to about 65% by weight, based on the weight of the brominated diester.

[0035] The brominated diester has the formula: [ka] In the formula, R a , R b , and R c Each of R has at least one carbon atom; a , R b , and R c At least one of R has at least one bromine atom. bhas at least one bromine atom.

[0036] R a and R c R each independently has 1 to about 6 carbon atoms, preferably 1 to about 5 carbon atoms, more preferably 1 to about 4 carbon atoms, and 1 to about 4 bromine atoms, preferably 1 to about 3 bromine atoms, more preferably 1 to about 2 bromine atoms. a and R c Each R may independently be a branched or straight chain alkyl group, a branched or straight chain alkenyl group, or an aryl group. a and R c Preferred alkyl groups include methyl, ethyl, n-propyl, isopropyl, and n-butyl, more preferably methyl, n-propyl, and isopropyl, preferred alkenyl groups include vinyl, allyl, butenyl, pentenyl, and hexenyl, and preferred aryl groups include phenyl. In some embodiments, R a and / or R c R may not contain bromine. a and R c may be the same or different, and in some embodiments, R a and R c are preferably the same.

[0037] R b is a group bridging two ester moieties, R b has preferably 2 to about 8 carbon atoms, preferably 2 to about 6 carbon atoms, and 1 to about 4 bromine atoms, preferably 1 to about 3 bromine atoms, more preferably 1 to 2 bromine atoms. b At least two carbon atoms of R form a bridge between the two ester moieties. b is preferably a group other than a phenylene group or an arylene group. b can be a branched or straight chain alkylenyl group, or a branched or straight chain alkenylenyl group. In some preferred embodiments, R bdoes not contain a quaternary carbon atom. b For the above, preferred alkyl groups include ethyl, n-propyl, n-butyl, and neopentyl, and preferred alkenyl groups include ethylenyl, propylenyl, butenyl, pentenyl, and and hexenyl, especially butenyl.

[0038] Bromine atom is R b In some embodiments, the group R a and R c does not contain a bromine atom. In other embodiments, the bromine atom is R a and / or R c and preferably at least one bromine atom is present in R a , R b , and R c Each of these exists.

[0039] R b When R contains a quaternary carbon atom, it is preferred that R a , R b , and R c At least one bromine atom is present in each of R b At least one bromine atom is present in the group R a and R c does not contain a bromine atom. a and R b None of the groups contain a quaternary carbon atom.

[0040] Preferred brominated diesters include 2,3-dibromobut-2-ene-1,4-diyl diacetate; 2,3-dibromobuten-2-ene-1,4-diylbis(2-methylpropanoate), also known as 2,3-dibromobutene-1,4-diyl-1,4-diisobutyrate; 2,3-dibromobut-2-ene-1,4-diylbis(2-bromobutanoate); 2,2-bis(bromomethyl)-1,3-propanediyl diacetate, also known as dibromoneopentyl diacetate; and 2,2-bis(bromomethyl)propane-1,3-diylbis(bromoacetate).

[0041] In some preferred embodiments of the present invention, the liquid electrolyte medium is ethylene carbonate, ethyl methyl carbonate, or a mixture thereof. More preferably, the lithium-containing salt is lithium hexafluorophosphate, lithium di(fluoro)(oxalato)borate, or lithium bis(oxalato)borate.

[0042] In some embodiments of the present invention, at least one electrochemical additive is included in the non-aqueous electrolyte solution.

[0043] In the practice of the invention, the electrochemical additive is soluble in or miscible with the liquid medium of the non-aqueous electrolyte solution. The electrochemical additive in liquid form is miscible with the liquid medium of the non-aqueous electrolyte solution, where "miscible" means that the electrochemical additive does not form a separate phase from the electrolyte solution. More specifically, the electrochemical additive is miscible if it forms a single phase in a mixture of 30% by weight ethylene carbonate and 70% by weight ethyl methyl carbonate containing 1.2 M lithium hexafluorophosphate after shaking for 24 hours with a stirring device, no separate phase is formed after shaking is stopped, and the electrochemical additive does not precipitate from the non-aqueous electrolyte solution or form a suspension or slurry.

[0044] The term "soluble" is typically used for solid electrochemical additives to indicate that the electrochemical additive, once dissolved, does not precipitate from or form a suspension or slurry in the non-aqueous electrolyte solution. More specifically, an electrochemical additive is soluble if, after shaking for 24 hours with a stirring device, it dissolves in a mixture of 30% by weight ethylene carbonate and 70% by weight ethyl methyl carbonate containing 1.2 M lithium hexafluorophosphate and does not form a precipitate, suspension or slurry after shaking is stopped. It is recommended and preferred that the electrochemical additive does not cause precipitation of any of the other components of the non-aqueous electrolyte solution or the formation of a suspension or slurry.

[0045] The brominated flame retardants, electrochemical additives, and mixtures thereof are generally stable to electrochemical cycling and preferably have low viscosity and / or do not significantly increase the viscosity of the non-aqueous electrolyte solution.

[0046] In various embodiments, the electrochemical additive comprises a) a non-ionic surfactant having from 3 to about 4 carbon atoms. a) a saturated cyclic carbonate having from 3 to about 4 carbon atoms and from 1 to about 2 fluorine atoms; b) a fluorine-containing saturated cyclic carbonate having from 3 to about 4 carbon atoms and from 1 to about 2 fluorine atoms; c) a tris(trihydrocarbylsilyl)phosphite having from 3 to about 6 carbon atoms; d) a trihydrocarbyl phosphate having from 3 to about 9 carbon atoms; e) a cyclic sultone having from 3 to about 4 carbon atoms; f) a saturated cyclic hydrocarbyl sulfite having a 5-membered ring and containing from 2 to about 4 carbon atoms; g) a saturated cyclic hydrocarbyl sulfate having a 5-membered ring and containing from 2 to about 4 carbon atoms; h) a cyclic dioxadithio polyoxide compound having a 6- or 7-membered ring and containing from 2 to about 4 carbon atoms; i) another lithium-containing salt; and j) a mixture of any two or more of the foregoing.

[0047] In some embodiments, the electrochemical additive is an unsaturated cyclic carbonate containing 3 to about 6 carbon atoms, preferably 3 to about 4 carbon atoms. Suitable unsaturated cyclic carbonates include vinylene carbonate (1,3-dioxol-2-one), 4-methyl-1,3-dioxol-2-one, and 4,5-dimethyl-1,3-dioxol-2-one. Vinylene carbonate is a preferred unsaturated cyclic carbonate. The unsaturated cyclic carbonate is preferably present in an amount of about 0.5% to about 12% by weight, more preferably about 0.5% to about 3% by weight, or about 8% to about 11% by weight, based on the total weight of the non-aqueous electrolyte solution.

[0048] When the electrochemical additive is a fluorine-containing saturated cyclic carbonate containing 3 to about 5 carbon atoms, preferably 3 to about 4 carbon atoms, and 1 to about 4 fluorine atoms, preferably 1 to about 2 fluorine atoms, suitable fluorine-containing saturated cyclic carbonates include 4-fluoro-ethylene carbonate and 4,5-difluoro-ethylene carbonate. Preferably, the fluorine-containing saturated cyclic carbonate is 4-fluoro-ethylene carbonate. The fluorine-containing saturated cyclic carbonate is preferably present in an amount of about 0.5% by weight to about 8% by weight, more preferably about 1.5% by weight to about 5% by weight, based on the total weight of the non-aqueous electrolyte solution.

[0049] The tris(trihydrocarbylsilyl)phosphite electrochemical additive contains 3 to about 9 carbon atoms, preferably about 3 to about 6 carbon atoms. The trihydrocarbylsilyl groups may be the same or different. Suitable tris(trihydrocarbylsilyl)phosphites include tris(trimethylsilyl)phosphite, bis(trimethylsilyl)(triethylsilyl)phosphite, tris(triethylsilyl)phosphite, bis(trimethylsilyl)(triethylsilyl)phosphite, bis(trimethylsilyl)(tri-n-propylsilyl)phosphite, and tris(tri-n-propylsilyl)phosphite. Tris(trimethylsilyl)phosphite is the preferred tris(trihydrocarbylsilyl)phosphite. The amount of tris(trihydrocarbylsilyl)phosphite is preferably about 0.1% by weight to about 5% by weight, more preferably about 0.15% by weight to about 4% by weight, and even more preferably about 0.2% by weight to about 3% by weight, based on the total weight of the nonaqueous electrolyte solution.

[0050] In some embodiments, the electrochemical additive is a trihydrocarbyl phosphate containing 3 to about 12 carbon atoms, preferably 3 to about 9 carbon atoms. The hydrocarbyl groups may be saturated or unsaturated, and the hydrocarbyl groups in the trihydrocarbyl phosphate may be the same or different. Suitable trihydrocarbyl phosphates include trimethyl phosphate, triethyl phosphate, dimethylethyl phosphate, tri-n-propyl phosphate, triallyl phosphate, and trivinyl phosphate. Triallyl phosphate is a preferred trihydrocarbyl phosphate. The trihydrocarbyl phosphate is generally present in an amount of about 0.5% to about 5% by weight, preferably about 1% to about 5% by weight, more preferably about 2% to about 3% by weight, based on the total weight of the non-aqueous electrolyte solution. The amount is about 4% by weight.

[0051] When the electrochemical additive is a cyclic sultone containing 3 to about 8 carbon atoms, preferably 3 to about 4 carbon atoms, suitable cyclic sultones include 1-propane-1,3-sultone (1,3-propane sultone), 1-propene-1,2-sultone (1,3-propene sultone), 1,3-butane sultone (5-methyl-1,2-oxathiolane 2,2-dioxide), 2,4-butane sultone (3-methyl-1,2-oxathiolane 2,2-dioxide), 1,4-butane sultone (1,2-oxathiane 2,2-dioxide), 2-hydroxy-alpha-toluenesulfonic acid sultone (3H-1,2-benzoxathiol 2,2-dioxide), and 1,8-naphthosultone. Preferred cyclic sultones include 1-propane-1,3-sultone, and 1-propene-,1,3-sultone. The amount of the cyclic sultone is preferably about 0.25% by weight to about 5% by weight, and more preferably about 0.5% by weight to about 4% by weight, based on the total weight of the nonaqueous electrolyte solution.

[0052] The saturated cyclic hydrocarbyl sulfite electrochemical additive contains 2 to about 6 carbon atoms, preferably 2 to about 4 carbon atoms, and has a 5- or 6-membered ring, preferably a 5-membered ring. One or more substituents, such as methyl or ethyl groups, preferably one or more methyl groups, can be present on the ring, and more preferably there are no substituents on the ring. Suitable saturated cyclic hydrocarbyl sulfites include 1,3,2-dioxathiolane 2-oxide (1,2-ethylene sulfite), 1,2-propanediol sulfite (1,2-propylene sulfite), 4,5-dimethyl-1,3,2-dioxathiolane 2-oxide, 1,3,2-dioxathiane 2-oxide, 4-methyl-1,3-dioxathiane, 2-oxide (1,3-butylene sulfite). Preferred cyclic hydrocarbyl sulfites include 1,3,2-dioxathiolane, 2-oxide (1,2-ethylene sulfite). The cyclic hydrocarbyl sulfite is preferably present in an amount of about 0.5% by weight to about 5% by weight, more preferably about 1% by weight to about 4% by weight, based on the total weight of the non-aqueous electrolyte solution.

[0053] In some embodiments, the electrochemical additive is a saturated cyclic hydrocarbyl sulfate containing 2 to about 6 carbon atoms, preferably 2 to about 4 carbon atoms, and having a 5- or 6-membered ring, preferably a 5-membered ring. One or more substituents, such as methyl or ethyl groups, preferably one or more methyl groups, can be present on the ring, and more preferably there are no substituents on the ring. Suitable saturated cyclic hydrocarbyl sulfates include 1,3,2-dioxathiolane 2,2-dioxide (1,2-ethylene sulfate), 1,3,2-dioxathiane 2,2-dioxide (1,3-propylene sulfate), 4-methyl-1,3,2-dioxathiane 2,2-dioxide (1,3-butylene sulfate), and 5,5-dimethyl-1,3,2-dioxathiane 2,2-dioxide. The saturated cyclic hydrocarbyl sulfate is preferably present in an amount of about 0.25% by weight to about 5% by weight, more preferably about 1% by weight to about 4% by weight, based on the total weight of the non-aqueous electrolyte solution.

[0054] When the electrochemical additive is a cyclic dioxadithiopolyoxide compound, the cyclic dioxadithiopolyoxide compound contains 2 to about 6 carbon atoms, preferably 2 to about 4 carbon atoms, and has a 6-membered, 7-membered, or 8-membered ring. Preferably, the cyclic dioxadithiopolyoxide compound contains 2 to about 4 carbon atoms and has a 6-membered or 7-membered ring. One or more substituents, such as methyl or ethyl groups, preferably one or more methyl groups, can be present on the ring, and more preferably, there are no substituents on the ring. Suitable cyclic dioxadithiopolyoxide compounds include 1,5,2,4-dioxadithiane 2,2,4,4-tetraoxide, 1,5,2,4-dioxadithiep ... Examples of suitable cyclic dioxadithio polyoxide compounds include cyclodithiophene 2,2,4,4-tetraoxide, 3-methyl-1,5,2,4-dioxadithiepane 2,2,4,4-tetraoxide, and 1,5,2,4-dioxadithiocane 2,2,4,4-tetraoxide. 1,5,2,4-dioxadithiane 2,2,4,4-tetraoxide is preferred. The amount of the cyclic dioxadithio polyoxide compound is preferably about 0.5% by weight to about 5% by weight, more preferably about 1% by weight to about 4% by weight, based on the total weight of the non-aqueous electrolyte solution.

[0055] The phrases "another lithium-containing salt" and "other lithium-containing salt" indicate that at least two lithium salts are used in the preparation of the electrolyte solution. When the electrochemical additive is another lithium-containing salt, it is preferably in an amount of about 0.5% to about 5% by weight, based on the total weight of the non-aqueous electrolyte solution. Suitable lithium-containing salts include all the lithium-containing salts mentioned above. Lithium di(fluoro)(oxolato)borate and lithium bis(oxolato)borate are preferred.

[0056] A mixture of any two or more of the aforementioned electrochemical additives can be used, including various electrochemical additives of the same type and / or different types of electrochemical additives. When a mixture of electrochemical additives is used, the total amount of electrochemical additives is about 0.25% by weight to about 5% by weight based on the total weight of the non-aqueous electrolyte solution. A mixture of unsaturated cyclic carbonate and saturated cyclic hydrocarbyl sulfite, or a mixture of cyclic sultones, tris(trihydrocarbylsilyl)phosphites, and cyclic dioxadithio polyoxide compounds is preferred.

[0057] Additional components often included in electrolyte solutions for lithium batteries can also be present in the electrolyte solution of the present invention. Such additional components include nitrile compounds such as succinonitrile and perfluoroalkylnitrile, and silazane compounds such as hexamethyldisilazane. Preferred additional components are nitrile compounds, with succinonitrile being the preferred nitrile compound. Typically, the amount of any component ranges from about 1% by weight to about 5% by weight, preferably from about 1% by weight to about 4% by weight, based on the total weight of the non-aqueous electrolyte solution.

[0058] In some preferred embodiments, a nitrile compound and another lithium-containing salt are components of the electrolyte solution. The nitrile compound and the lithium-containing salt are as described above. Preferably, the nitrile compound is succinonitrile, and the other lithium-containing salt is preferably lithium di(fluoro)(oxalato)borate.

[0059] Another embodiment of the present invention provides a process for producing a non-aqueous electrolyte solution for a lithium battery, the process comprising: i) a liquid electrolyte medium; ii) a lithium-containing salt; and iii) a) a brominated monoester, α) has 3 carbon atoms and at least one bromine atom, or β) a brominated monoester having at least 4 carbon atoms and at least one bromine atom and represented by the following formula: [ka] (In the formula, R 1 and R 2 Each of R has at least one carbon atom; 1 and R 2 at least one of R 2 is a benzyl group and at least one bromine atom is present in the benzyl group, R 1 is a branched or linear alkyl group, and b) a brominated diester having at least 6 carbon atoms and at least one bromine atom and represented by the formula: [ka] (In the formula, R a , R b , and R c Each of R has at least one carbon atom; a , R b , and R c and at least one oxygen-containing brominated flame retardant selected from, at least one of which has at least one bromine atom.

[0060] Optionally, the components further include iv) at least one electrochemical additive as described above. The oxygen-containing bromine-based flame retardant is present in the electrolyte solution in an amount of flame retardant. The components can be combined in any order, but it is preferred that all components are added to the liquid electrolyte medium. It is also preferred that the optional components are added to the liquid electrolyte medium. The characteristics and preferences of the liquid electrolyte medium, the lithium-containing salt, the oxygen-containing bromine-based flame retardant(s), the electrochemical additive(s), and the amount of each component are as described above.

[0061] Yet another embodiment of the present invention provides a process for producing a non-aqueous electrolyte solution for a lithium battery. The process includes blending components including: i) a liquid electrolyte medium; ii) a lithium-containing salt; and iii) at least one oxygen-containing bromine-based flame retardant. Optionally, the components further include iv) at least one electrochemical additive as described above. The oxygen-containing bromine-based flame retardant is selected from the group consisting of methyl bromoacetate, 2-bromoethyl acetate, 4-bromobutyl acetate, 2-bromovinyl acetate, 3-bromoallyl acetate, 3-bromoallyl butyrate, 2,3-dibromoprop-2-en-1-yl acetate, 2,3-dibromoprop-2-en-1-yl propionate, 2,3-dibromoprop-2-en-1-yl 2-methylpropanoate, (3,5-dibromophenyl)methyl ether, 2,3-dibromoprop-2-en-1-yl ... methyl acetate, 3-bromo-2,2-bis(bromomethyl)propyl acetate, methyl 3-bromo-2-propenoate, methyl 2-bromo-acrylate, 2,3-dibromoprop-2-en-1-yl bromoacetate, (3,5-dibromophenyl)methyl bromoacetate, 2,3-dibromobut-2-ene-1,4-diyl diacetate, 2,3-dibromobut-2-ene-1,4-diylbis(2-methylpropanoate), 2 ,3-dibromobut-2-ene-1,4-diylbis(2-bromobutanoate), 2,2-bis(bromomethyl)-1,3-propanediyl diacetate, and 2,2-bis(bromomethyl)propane-1,3-diylbis(bromoacetate). The preferences for the liquid electrolyte medium, lithium-containing salt, electrochemical additive(s), and the amounts of each component are as described above.

[0062] The non-aqueous electrolyte solution of the present invention containing one or more brominated flame retardants is typically used in a non-aqueous lithium battery, which includes a positive electrode, a negative electrode, and a non-aqueous electrolyte solution. The non-aqueous lithium battery can be obtained by injecting the non-aqueous electrolyte solution between a negative electrode and a positive electrode, optionally having a separator therebetween.

[0063] The molecules 2,3-dibromoprop-2-en-1-yl propanoate, 2,3-dibromoprop-2-en-1-yl 2-methylpropanoate, 2,3-dibromoprop-2-en-1-yl bromoacetate, 2,3-dibromobut-2-ene-1,4-diylbis(2-methylpropanoate), 2,3-dibromobut-2-ene-1,4-diylbis(2-bromobutanoate), and 2,2-bis(bromomethyl)propane-1,3-diylbis(bromoacetate) are new compositions of matter.

[0064] The following examples are presented for illustrative purposes and are not intended to impose limitations on the scope of the invention.

[0065] In Example 1, a modified horizontal UL-94 test was performed. This modified horizontal UL-94 test is very similar to known published horizontal UL-94 tests. In this regard, see, for example, Otsuki, M. et al. "Flame-Retardant Additives for Lithium-Ion Batteries." Lithium-Ion Batteries. Ed. M. Yoshio et al. New York, Springer, 2009, 275-289. The modified UL-94 test was as follows: The core was cut from a cylindrical fiberglass core, the cut edge was smoothed, and the surface of the core was cleaned of dust and particles. The core was dried at 120°C for 20 hours before testing. The length of the core was 5 ± 0.1 in (12.7 ± 0.25 cm). Each specimen to be tested was prepared in a 4 ounce (120 mL) glass vial in a dry box and the desired amount of flame retardant and, if present, electrochemical additives were combined with the desired amount of electrolyte solution to form an electrolyte solution containing flame retardant, e.g., 20% by weight brominated flame retardant with 80% by weight electrolyte solution. Prior to combination with the flame retardant, the electrolyte solution contained 1.2 M LiPF in ethylene carbonate / ethyl methyl carbonate (3:7 by weight). 6 Each wick was immersed in the electrolyte solution for 30 minutes. Each test specimen was removed from the electrolyte solution and held above the electrolyte solution until no more drips remained, then placed in a 4 oz. (120 mL) glass jar and capped to prevent evaporation of the electrolyte solution. The burner was ignited and adjusted to produce a blue flame 20±1 mm high. The test specimen was removed from the 4 oz. (120 mL) glass bottle container and the specimen was placed horizontally on a metal support fixture with one end of the wick secured in place. If the exhaust fan was running, it was shut off for the test. The flame was at an angle of 45±2 degrees to the horizontal wick. One way to accomplish this, if the burner had a burner tube, was to tilt the central axis of the burner tube toward the end of the specimen at an angle of 45±2 degrees from the horizontal. The flame was applied to the free end of the specimen without changing its position for 30±1 seconds, and the burner was removed after 30±1 seconds or as soon as the burning front on the specimen reached the 1 inch (2.54 cm) mark. If the specimen continued to burn after the test flame was removed, either the time (in seconds) for the flame to go out or the time (in seconds) for the burn front (flame) to reach from the 1 inch (2.54 cm) mark to the 4 inch (10.16 cm) mark was recorded.

[0066] If the flame was extinguished when the burner was removed, the specimen was considered "not flammable." If the flame was extinguished before reaching the 1 inch (2.54 cm) mark, the specimen was considered "flame-retardant." If the flame was extinguished before reaching the 4 inch (10.16 cm) mark, the specimen was considered "self-extinguishing."

[0067] Each modified horizontal UL-94 test result reported below is the average of three tests.

[0068] Example 1 Various non-aqueous electrolyte solutions containing different oxygen-containing brominated flame retardants prepared as described above were subjected to the modified UL-94 test described above. The results are summarized below in Table 1. As stated above, the reported values ​​are the average of triplicates. [Table 1]

[0069] Example 2 Coin cells were also tested for several flame retardants. Coin cells were assembled using a non-aqueous electrolyte solution containing the desired amount of flame retardant. The coin cells were then subjected to electrochemical cycling of CCCV charging to 4.2 V at C / 5, followed by CC discharging from C / 5 to 3.0 V with a current interruption of C / 50 during the CV portion.

[0070] One sample was a flame retardant-free non-aqueous electrolyte solution of 1.2 M LiPF in ethylene carbonate / ethyl methyl carbonate (weight ratio 3:7). 6 The remaining samples contained the desired amount of flame retardant in the electrolyte solution. The results are summarized in Table 2 below. The error range for the coulombic efficiency is about ±0.5% to about ±1.0%. [Table 2]

[0071] Example 3 Synthesis of 2,3-dibromoprop-2-en-1-yl propanoate A 500 mL four-neck round bottom flask was charged with 2,3-dibromoprop-2-en-1-ol (35.5 g), propionic acid (34.71 g), p-toluenesulfonic acid monohydrate (1.30 g) and toluene (250 mL). The mixture was heated to reflux with stirring and maintained at 113-117 °C for 5 h, during which time water was removed and collected via a Dean-Stark apparatus. The reaction was monitored by gas chromatography (GC). After GC showed the reaction to be complete, the reaction mixture was cooled to room temperature, washed several times with saturated aqueous sodium bicarbonate (4 × 90 mL) and the phases were separated. The organic layer was washed with MgSO 4 After filtration, the toluene was removed from the organic layer using a rotary evaporator, and the organic layer was then further dried under high vacuum (about 1 Torr) to give 40.56 g of the product as a clear liquid.

[0072] Example 4 Synthesis of 2,3-dibromoprop-2-en-1-yl bromoacetate In a 500 mL four-neck round bottom flask, add 2,3-dibromoprop-2-en-1-ol (17.2 g), bromoacetate (30 g), p-toluenesulfonic acid monohydrate (0. The mixture was charged with toluene (250 mL). The mixture was heated to reflux with stirring and maintained at 115-117 °C for 3 h, during which time water was removed and collected via a Dean-Stark apparatus. The reaction was monitored by gas chromatography (GC). After GC showed the reaction was complete, the reaction mixture was cooled to room temperature, washed several times with saturated aqueous sodium bicarbonate (4 × 80 mL), and the phases were separated. The organic layer was washed with MgSO 4 After filtration, the toluene was removed from the organic layer using a rotary evaporator, and the organic layer was then further dried under high vacuum (55° C. at 0 Torr, 1.5 h) to give 24.97 g of product as a clear liquid.

[0073] Example 5 Synthesis of 2,3-dibromoprop-2-ene-1-methylpropanoate A 500 mL four-neck round bottom flask was charged with 2,3-dibromobut-2-en-1-ol (34.47 g), isobutyric acid (39.65 g), p-toluenesulfonic acid monohydrate (1.30 g) and toluene (250 mL). The mixture was heated to reflux with stirring and maintained at 116-118 °C for 4 h, during which time water was removed and collected via a Dean-Stark apparatus. The reaction was monitored by gas chromatography (GC). After GC showed the reaction to be complete, the reaction mixture was cooled to room temperature, washed several times with saturated aqueous sodium bicarbonate (5 × 80 mL) and the phases were separated. The organic layer was washed with MgSO 4 After filtration, the toluene was removed from the organic layer using a rotary evaporator, and the organic layer was then further dried under high vacuum (about 1 Torr) to give 41.12 g of the product as a clear liquid.

[0074] Example 6 Synthesis of 2,3-dibromobut-2-ene-1,4-diylbis(2-methylpropanoate) A 500 mL four-neck round bottom flask was charged with 2,3-dibromobut-2-ene-1,4-diol (49.18 g), isobutyric acid (105.60 g), p-toluenesulfonic acid monohydrate (3.60 g) and toluene (250 mL). The mixture was heated to reflux with stirring and maintained at 118 °C for 2 h, during which time water was removed and collected via a Dean-Stark apparatus. The reaction was monitored by gas chromatography (GC). After GC showed the reaction to be complete, the reaction mixture was cooled to room temperature, washed several times with saturated aqueous sodium bicarbonate (8 × 80 mL) and the phases were separated. The organic layer was washed with MgSO 4 After filtration, the toluene was removed from the organic layer using a rotary evaporator, and the organic layer was then further dried under high vacuum (about 1 Torr) to give 73.77 g of the product as a clear liquid.

[0075] Example 7 Synthesis of 2,3-dibromobut-2-ene-1,4-diylbis(2-bromobutanoate) A 500 mL four-neck round bottom flask was charged with 2,3-dibromobut-2-ene-1,4-diol (20 g), 2-bromobutyric acid (54.33 g), p-toluenesulfonic acid monohydrate (1.32 g) and toluene (250 mL). The mixture was heated to reflux with stirring and maintained at 117 °C for 4 h, during which time water was removed and collected via a Dean-Stark apparatus. The reaction was monitored by gas chromatography (GC). After GC showed the reaction to be complete, the reaction mixture was cooled to room temperature, washed several times with saturated aqueous sodium bicarbonate (5 × 150 mL) and the phases were separated. The organic layer was washed with MgSO 4 After filtration, the toluene was removed from the organic layer using a rotary evaporator, and the organic layer was then further dried under high vacuum (about 1 Torr) to give 37.69 g of the product as a slightly yellow liquid.

[0076] Example 8 Synthesis of 2,2-bis(bromomethyl)propane-1,3-diylbis(bromoacetate) A 500 mL four-neck round bottom flask was charged with 2,2-bis(bromomethyl)propane-1,3-diol (20 g), bromoacetate (42.44 g), p-toluenesulfonic acid monohydrate (1.23 g) and toluene (250 mL). The mixture was heated to reflux with stirring and maintained at 114 °C for 4.5 h, during which time water was removed and collected via a Dean-Stark apparatus. The reaction was monitored by gas chromatography (GC). After GC showed the reaction to be complete, the reaction mixture was cooled to room temperature, washed several times with saturated aqueous sodium bicarbonate (5 × 150 mL) and the phases were separated. The organic layer was washed with MgSO 4 After filtration, the toluene was removed from the organic layer using a rotary evaporator, and the organic layer was then further dried under high vacuum (about 1 Torr) to give 33.38 g of the product as a clear liquid.

[0077] An ingredient referred to by chemical name or formula anywhere in this specification or claims, whether referred to in the singular or plural, is identified as being present prior to contact with another substance (e.g., another component, solvent, etc.) referred to by the chemical name or chemical type. It does not matter what chemical change, transformation, and / or reaction occurs in the resulting mixture or solution, since such change, transformation, and / or reaction is the natural result of bringing the particular ingredients together under the conditions required in accordance with this disclosure. The ingredient is therefore identified as the ingredient that is brought together in connection with performing a desired operation or forming a desired composition. Also, although the claims below may refer to a substance, component, and / or ingredient in the present tense (such as "comprising," "is," etc.), the reference is to the substance, component, or ingredient as it existed at the time immediately prior to its first contact, blend, or mixing with one or more other substances, components, and / or ingredients according to this disclosure. The fact that the substances, components, or ingredients may have lost their original identity due to chemical reaction or transformation in the course of the contacting, blending or mixing operations, when carried out in accordance with this disclosure and the ordinary skill of the chemist, is therefore of no practical importance.

[0078] The present invention may comprise, consist of, or consist essentially of the materials and / or procedures recited herein.

[0079] As used herein, the term "about" modifying the amount of a component in the composition or used in the method of the present invention refers to variations in numerical quantity that may occur, for example, through typical measurements and liquid handling procedures used to make concentrates or use solutions in the real world; through inadvertent errors in these procedures; through differences in manufacture, source, or purity of components used to make the composition or carry out the method; etc. The term about also encompasses amounts that differ due to different equilibrium conditions of the composition resulting from a particular initial mixture. Whether or not modified by the term "about," the claims encompass the equivalent of the amount.

[0080] The article "a" or "an" as used herein is not intended, and should not be construed as, limiting the detailed description or claims to a single element to which the article refers, unless expressly stated otherwise. Rather, the article "a" or "an" as used herein is intended to cover one or more such elements, unless the context clearly indicates otherwise.

[0081] This invention is susceptible to considerable variation in its practice, and therefore the foregoing description is not intended to limit, and should not be construed as limiting, the invention to the particular exemplifications presented hereinabove.

Claims

1. 1. A non-aqueous electrolyte solution for a lithium battery, the solution comprising: i) a liquid electrolyte medium; ii) a lithium-containing salt; and iii) at least one oxygen-containing brominated flame retardant, a) a brominated monoester, α) has 3 carbon atoms and at least one bromine atom, or β) the brominated monoester having at least 4 carbon atoms and at least one bromine atom and represented by the following formula: 【Chemistry 1】 (In the formula, R 1 and R 2 Each of R has at least one carbon atom; 1 and R 2 at least one of R 2 is a benzyl group, and when at least one bromine atom is present in the benzyl group, R 1 is a branched or linear alkyl group, and b) a brominated diester having at least 6 carbon atoms and at least one bromine atom and represented by the formula: 【Chemistry 2】 (In the formula, R a , R b , and R c Each of R has at least one carbon atom; a , R b , and R c at least one of which has at least one bromine atom; and

2. The oxygen-containing bromine-based flame retardant is I) a) a brominated monoester having from 4 to about 12 carbon atoms and / or from 1 to about 8 bromine atoms, or b) a brominated diester having from 6 to about 20 carbon atoms and / or from 1 to about 8 bromine atoms, or II) a) R 1 a brominated monoester having at least one bromine atom and from 1 to about 8 carbon atoms, or 2. The solution of claim 1, wherein b) is a brominated diester having from about 6 to about 18 carbon atoms and / or from 1 to about 6 bromine atoms.

3. The oxygen-containing bromine-based flame retardant is I) a) R 2 a brominated monoester having at least one bromine atom and from 2 to about 8 carbon atoms, or b) R b has at least one bromine atom, and / or R a and R c or a brominated diester, II) a) R 1 and R 2 each having at least one bromine atom, R 1 has 1 to about 8 carbon atoms; R 2 having 1 to about 9 carbon atoms, or b) at least one bromine atom is R a , R b , and R c 2. The solution of claim 1 , wherein each of the brominated diesters is a brominated diester present in each of the brominated diesters.

4. The oxygen-containing bromine-based flame retardant is a) R 2 does not contain a quaternary carbon atom, or b) R b 2. The solution of claim 1 , wherein is a brominated diester that does not contain a quaternary carbon atom.

5. 3. The solution of claim 1, wherein the brominated monoester is 2-bromoethyl acetate, 4-bromobutyl acetate, 2-bromovinyl acetate, 3-bromoallyl acetate, 3-bromoallyl butyrate, 2,3-dibromoprop-2-en-1-yl acetate, 2,3-dibromoprop-2-en-1-yl propanoate, (3,5-dibromophenyl)methyl acetate, 3-bromo-2,2-bis(bromomethyl)propyl acetate, methyl 3-bromo-2-propenoate, methyl 2-bromo-acrylate, 2,3-dibromoprop-2-en-1-yl bromoacetate, or (3,5-dibromophenyl)methyl bromoacetate.

6. R b 4. The solution of claim 1, wherein 2 to about 4 carbon atoms form a bridge between the two ester moieties in the brominated diester.

7. The solution of any one of claims 1 to 3, wherein the brominated diester is 2,3-dibromobut-2-ene-1,4-diyl diacetate, 2,3-dibromobut-2-ene-1,4-diyl bis(2-methylpropanoate), 2,3-dibromobut-2-ene-1,4-diyl bis(2-bromobutanoate), 2,2-bis(bromomethyl)-1,3-propanediyl diacetate, or 2,2-bis(bromomethyl)propane-1,3-diyl bis(bromoacetate).

8. 5. The solution of claim 1, wherein the oxygen-containing brominated flame retardant is in an amount of about 9.5% by weight or more of bromine, based on the total weight of the solution.

9. 5. The solution of claim 1, wherein the liquid electrolyte medium is ethylene carbonate, ethyl methyl carbonate, or a mixture thereof, and / or the lithium-containing salt is lithium hexafluorophosphate, lithium di(fluoro)(oxalato)borate, or lithium bis(oxalato)borate.

10. moreover, I) a) an unsaturated cyclic carbonate containing from 3 to about 6 carbon atoms; b) fluorine-containing saturated cyclic carbonates containing from 3 to about 5 carbon atoms and from 1 to about 4 fluorine atoms; c) tris(trihydrocarbylsilyl)phosphites containing from 3 to about 9 carbon atoms; d) trihydrocarbyl phosphates containing from 3 to about 12 carbon atoms; e) cyclic sultones containing from 3 to about 8 carbon atoms; f) saturated cyclic hydrocarbyl sulfites having five or six membered rings and containing from 2 to about 6 carbon atoms; g) saturated cyclic hydrocarbyl sulfates having five or six membered rings and containing from 2 to about 6 carbon atoms; h) cyclic dioxadithio polyoxide compounds having 6, 7, or 8 membered rings and containing from 2 to about 6 carbon atoms; i) another lithium-containing salt, and j) a mixture of any two or more of the foregoing; or II) a) an unsaturated cyclic carbonate containing from 3 to about 4 carbon atoms; b) fluorine-containing saturated cyclic carbonates containing from 3 to about 4 carbon atoms and from 1 to about 2 fluorine atoms; c) tris(trihydrocarbylsilyl)phosphites containing from 3 to about 6 carbon atoms; d) trihydrocarbyl phosphates containing from 3 to about 9 carbon atoms; e) cyclic sultones containing from 3 to about 4 carbon atoms; f) saturated cyclic hydrocarbyl sulfites having a five-membered ring and containing from 2 to about 4 carbon atoms; g) saturated cyclic hydrocarbyl sulfates having a five-membered ring and containing from 2 to about 4 carbon atoms; h) cyclic dioxadithiopolyoxide compounds containing 6- or 7-membered rings and from 2 to about 4 carbon atoms; i) another lithium-containing salt, and j) a mixture of any two or more of the foregoing.

11. The electrochemical additive is a) an unsaturated cyclic carbonate in an amount of about 0.5% to about 12% by weight, based on the total weight of the non-aqueous electrolyte solution; b) a fluorine-containing saturated cyclic carbonate in an amount of about 0.5% to about 8% by weight, based on the total weight of the nonaqueous electrolyte solution; c) tris(trihydrocarbylsilyl)phosphate in an amount of about 0.1% to about 5% by weight, based on the total weight of the non-aqueous electrolyte solution; d) a trihydrocarbyl phosphate in an amount of about 0.5% to about 5% by weight, based on the total weight of the non-aqueous electrolyte solution; e) a cyclic salt in an amount of about 0.25% by weight to about 5% by weight based on the total weight of the nonaqueous electrolyte solution; Sultana, f) a saturated cyclic hydrocarbyl sulfite in an amount of about 0.5% to about 5% by weight, based on the total weight of the non-aqueous electrolyte solution; g) a saturated cyclic hydrocarbyl sulfate in an amount of about 0.25% to about 5% by weight, based on the total weight of the non-aqueous electrolyte solution; h) a cyclic dioxadithio polyoxide compound in an amount of about 0.5% by weight to about 5% by weight based on the total weight of the non-aqueous electrolyte solution; i) another lithium-containing salt in an amount of about 0.5% to about 5% by weight, based on the total weight of the nonaqueous electrolyte solution; and j) a mixture of any two or more of the foregoing.

12. 11. The solution of claim 10, wherein each electrochemical additive is not used with other electrochemical additives.

13. The solution according to any one of claims 1 to 4, wherein the solution further comprises a nitrile compound, and optionally the nitrile compound is succinonitrile, or the solution further comprises a nitrile compound and another lithium-containing salt, and optionally the nitrile compound is succinonitrile and the lithium-containing salt is lithium di(fluoro)(oxalato)borate.

14. The at least one oxygen-containing brominated flame retardant is selected from the group consisting of methyl bromoacetate, 2-bromoethyl acetate, 4-bromobutyl acetate, 2-bromovinyl acetate, 3-bromoallyl acetate, 3-bromoallyl butyrate, 2,3-dibromoprop-2-en-1-yl acetate, 2,3-dibromoprop-2-en-1-yl propanoate, (3,5-dibromophenyl)methyl acetate, 3-bromo-2,2-bis(bromomethyl)propyl acetate, methyl 3-bromo-2-propenoate, methyl 2-bromo-acrylate, 2,3-dibromoprop-2-en-1-yl bromoacetate, 2,3-dibromoprop-2-en-1-yl 2-methylpropanoate, (3,5-dibromophenyl)methyl bromoacetate, 2,3-dibromobut-2-ene-1,4-diyl diacetate, 2,3-dibromobut-2-ene-1,4-diyl bis(2-methylpropanoate), 2,3-dibromobut-2-ene-1,4-diyl bis(2-bromobutanoate), 2,2-bis(bromomethyl)-1,3-propanediyl diacetate, and 2,2-bis(bromomethyl)propane-1,3-diyl bis(bromoacetate).

15. 15. The solution of claim 14, wherein the oxygen-containing brominated flame retardant is in an amount of about 9.5 wt.% or greater of bromine, based on the total weight of the solution.

16. 16. The solution of any of claims 14 to 15, wherein the liquid electrolyte medium is ethylene carbonate, ethyl methyl carbonate, or a mixture thereof, and / or the lithium-containing salt is lithium hexafluorophosphate, lithium di(fluoro)(oxalato)borate, or lithium bis(oxalato)borate.

17. 16. The solution of any one of claims 14 to 15, wherein the solution further comprises a nitrile compound, optionally the nitrile compound is succinonitrile, or a nitrile compound and another lithium-containing salt, optionally the nitrile compound is succinonitrile and the lithium-containing salt is lithium di(fluoro)(oxalato)borate.

18. A positive electrode, a negative electrode, and a nonaqueous electrolyte solution according to any one of claims 1 to 4 or 14 to 16. Including, non-aqueous lithium batteries.

19. 1. A process for producing a non-aqueous electrolyte solution for a lithium battery, the process comprising: i) a liquid electrolyte medium; ii) a lithium-containing salt; and iii) at least one oxygen-containing brominated flame retardant, a) a brominated monoester, α) has 3 carbon atoms and at least one bromine atom, or β) the brominated monoester having at least 4 carbon atoms and at least one bromine atom and represented by the following formula: 【Chemistry 3】 (In the formula, R 1 and R 2 Each of R has at least one carbon atom; 1 and R 2 at least one of R 2 is a benzyl group, and when at least one bromine atom is present in the benzyl group, R 1 is a branched or linear alkyl group, and b) a brominated diester having at least 6 carbon atoms and at least one bromine atom and represented by the formula: 【Chemistry 4】 (In the formula, R a , R b , and R c Each of R has at least one carbon atom; a , R b , and R c and said at least one oxygen-containing brominated flame retardant selected from the group consisting of:

20. The component further comprises: a) an unsaturated cyclic carbonate containing from 3 to about 6 carbon atoms; b) fluorine-containing saturated cyclic carbonates containing from 3 to about 5 carbon atoms and from 1 to about 4 fluorine atoms; c) tris(trihydrocarbylsilyl)phosphites containing from 3 to about 9 carbon atoms; d) trihydrocarbyl phosphates containing from 3 to about 12 carbon atoms; e) cyclic sultones containing from 3 to about 8 carbon atoms; f) saturated cyclic hydrocarbyl sulfites having five or six membered rings and containing from 2 to about 6 carbon atoms; g) saturated cyclic hydrocarbyl sulfates having five or six membered rings and containing from 2 to about 6 carbon atoms; h) cyclic dioxadithio polyoxide compounds having 6, 7, or 8 membered rings and containing from 2 to about 6 carbon atoms; i) another lithium-containing salt, and j) a mixture of any two or more of the foregoing.

20. The process of claim 19, further comprising a chemical additive.

21. The at least one oxygen-containing bromine-based flame retardant is selected from the group consisting of methyl bromoacetate, 2-bromoethyl acetate, 4-bromobutyl acetate, 2-bromovinyl acetate, 3-bromoallyl acetate, 3-bromoallyl butyrate, 2,3-dibromoprop-2-en-1-yl acetate, 2,3-dibromoprop-2-en-1-yl propanoate, (3,5-dibromophenyl)methyl acetate, 3-bromo-2,2-bis(bromomethyl)propyl acetate, methyl 3-bromo-2-propenoate, methyl 2-bromo-acrylate, 2,3-dibromoprop-2-en-1-yl bromoacetate, 2,3-dibromophenyl ether ...

20. The process for producing a non-aqueous electrolyte solution for a lithium battery according to claim 19, wherein the aryl group is selected from the group consisting of moprop-2-en-1-yl 2-methylpropanoate, (3,5-dibromophenyl)methyl bromoacetate, 2,3-dibromobut-2-ene-1,4-diyl diacetate, 2,3-dibromobut-2-ene-1,4-diyl bis(2-methylpropanoate), 2,3-dibromobut-2-ene-1,4-diyl bis(2-bromobutanoate), 2,2-bis(bromomethyl)-1,3-propanediyl diacetate, and 2,2-bis(bromomethyl)propane-1,3-diyl bis(bromoacetate).

22. 22. The process of claim 21, wherein the components further comprise at least one electrochemical additive selected from vinylene carbonate, 4-fluoro-ethylene carbonate, tris(trimethylsilyl)phosphite, triallyl phosphate, 1,3-propane sultone, 1,3-propene sultone, ethylene sulfite, 1,3,2-dioxathiolane 2,2-dioxide, 1,5,2,4-dioxadithiane 2,2,4,4-tetraoxide, lithium di(fluoro)(oxalato)borate, lithium bis(oxalato)borate, and mixtures of any two or more thereof.

23. Each of the following molecules is individually claimed as a novel composition of matter: 2,3-dibromoprop-2-en-1-yl-propanoate, 2,3-dibromoprop-2-en-1-yl 2-methylpropanoate, 2,3-dibromoprop-2-en-1-yl bromoacetate, 2,3-dibromobut-2-ene-1,4-diylbis(2-methylpropanoate), 2,3-Dibromobut-2-ene-1,4-diylbis(2-bromobutanoate).

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