Multifunctional silanes and electrolyte compositions containing them

Abstract

Multi-functional compounds of the structure: electrolyte compositions containing them, and electrochemical devices that utilize the electrolyte compositions.

Description

[0001] MULTIFUNCTIONAL SILANES AND ELECTROLYTE COMPOSITIONS CONTAINING THEM

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] Priority is hereby claimed to provisional application Ser. No. 63 / 634,054, filed April 15, 2024, which is incorporated herein by reference.

[0004] BACKGROUND

[0005] Liquid electrolytes in Li-ion batteries conventionally comprise a lithium salt, usually LiPF6, in an organic solvent blend of ethylene carbonate (EC) and one or more co-solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), or ethylmethyl carbonate (EMC). Unfortunately, LiPFe is unstable in these carbonate solvents above 60°C, as well as at charge voltages above 4.3 volts. Operation of a Li-ion battery’ above this temperature or voltage results in rapid degradation of electrode materials and battery performance. In addition, current Li-ion electrolyte solvents exhibit flashpoints around 35°C, and are the major source of the energy' released during an extreme Li-ion cell failure. Given these significant limitations, current electrolytes are impeding the development of advanced Li-ion batteries for all uses, including portable products, electric drive vehicles (EDVs), and utilityscale use. A dramatic reduction in battery failure rate is also required for large scale Li-ion batteries to effectively serve applications in EDVs and grid storage.

[0006] Thus, there is a long-felt and unmet need for improved electroly te solutions in energy' storage devices such as Li-ion batteries.

[0007] SUMMARY

[0008] Disclosed herein are organosilicon (OS) compounds for use as electrolyte solvents in electrochemical devices, among other uses.

[0009] In general, OS compounds are environmentally friendly, non-flammable, high temperature-resistant materials. These characteristics make OS materials well-suited for use as electrolyte solvents, binders, and coatings in energy storage devices. OS -based electrolytes are compatible with all lithium (Li) based electrochemical systems, including primary’ and rechargeable batteries, (i.e. Li-ion, Li-air), and capacitors (i.e. super / ultra- capacitors). The process of designing OS-based electrolytes into a Li battery involves limited changes in the cell design, and these electrolytes can be incorporated into production operations with existing manufacturing processes and equipment. The OS compounds described herein can be used as liquid electrolyte solvents that replace the carbonate based solvent system in traditional Li-ion batteries. The OS-based solvents provide significant improvements in performance and abuse tolerance in Li-ion batteries, including increased thermal stability for longer life at elevated temperatures, increased electrolyte flash points for improved safety, increased voltage stability to allow use of high voltage cathode materials and achieve higher energy density, reduced battery failure rates for consistency with the requirements for large scale Li batteries used in EDV and grid storage applications, and compatibility with materials currently in use in Li-ion batteries for ease of adoption in current designs. Electrical double-layer capacitor (EDLC) devices have also demonstrated functionality with OS based electrolytes. The OS compounds described herein can be used in OS-based electrolyte blends to meet the requirements of specific applications in the industrial, military, and consumer product devices.

[0010] Thus, disclosed and claimed herein are compounds of Formula I: (Formula I) wherein:

[0011] “a” is an integer from 1 to 4;

[0012] “b’" is an integer from 1 to 3;

[0013] “c,” “d,” and “e” are each independently an integer from 0 to 3;

[0014] •‘a” + -‘d” < 4; each R is independently selected from halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alky l, alkenyl, and alkynyl; each R3and R5is independently absent or selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl, (Formula II); each R1, R2, R4, and R6is independently selected from the group consisting of C1-15 linear or branched alkylene and C1-15 halo-substituted, linear or branched alkylene, or R2is absent; each X is independently an organic polar group selected from moieties having a valency of 2 to 4 in Group A; each Y and Z is independently an organic polar group selected from Group A or is

[0015] Group A is an organic polar group selected from the group consisting of: wherein a curved bond denotes a divalent -(CH2)2-6-(alkylenyl) bridging moiety.

[0016] In certain versions of the compounds, when a single R group is present, preferably the R is fluorine; and when two or more R groups are present, preferably at least one R is fluorine.

[0017] In certain versions of the compounds, each X may optionally and independently be an organic polar group selected from the group consisting of and

[0018] In certain versions of the compounds, when a single Y group is present, preferably the Y is selected from Group A; and when two or more Y groups are present, preferably at least one Y is selected from Group A.

[0019] In certain versions of the compounds, each Y may optionally and independently be an organic polar group selected from the group consisting of and

[0020] In one version of the compounds, “a” is 1,££b'’ is 1 to 2, and “d” is 0. Optionally,££c'’ is 0 or 1. When “c” is 1, R3is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alky nyl. In this version, the silicon atom is substituted with three R groups. In an optional embodiment, at least one R is fluorine, and each R1and R2is independently selected from the group consisting of Ci-6 linear or branched alkylene.

[0021] In an alternative version of the compounds, "‘a” is 2, “b” is 1 to 2, and “d” is 0. Optionally, “c” is 0 or 1. When “c” is 1, R3is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl. In this version, the silicon atom is substituted with two R groups. In an optional embodiment, at least one R is fluorine, and each R1and R2is independently selected from the group consisting of Ci-6 linear or branched alkylene.

[0022] In yet another alternative version of the compounds, “a” is 3, “b” is 1 to 2, and “d” is 0. Optionally, “c” is 0 or 1. When “c’‘ is 1, R3is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl. In this version, the silicon atom is substituted with a single R group. In an optional embodiment, the R group is fluorine, and each R1and R2is independently selected from the group consisting of Ci-6 linear or branched alkylene.

[0023] In yet another alternative version of the compounds, “a"’ is 4, “b” is 1 to 2, and “d’‘ is 0. Optionally, “c” is 0 or 1. When “c” is 1, R3is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl. In this version, R is not present. In an optional embodiment, each R1and R2is independently selected from the group consisting of Ci-6 linear or branched alkylene.

[0024] In yet another alternative version of the compounds, ‘‘d?’ is I to 3, and each R4is independently selected from the group consisting of Ci-6 linear or branched alkylene. Optionally, “e’‘ is 0 or 1. when “e” is 1, R5is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl.

[0025] Also disclosed herein is a non-aqueous electrolyte composition comprising, in combination, one or more compounds as described above and a lithium-containing salt. Also disclosed herein is an electrochemical device comprising the electrolyte composition. The compounds disclosed herein are highly useful for formulating electrolytes for use in chargestorage devices of all kinds (e.g., cells, batteries, capacitors, and the like).

[0026] The objects and advantages of the compounds and electrolyte formulations will appear more fully from the following detailed description and accompanying drawings.

[0027] BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 is a graph depicting oxidation using a platinum electrode of OS3 (FIS3MN), FIS3MOE, and FIS3MOEN in the presence of IM LiPFe.

[0029] FIG. 2A and FIG. 2B show the first cycle and second cycle (respectively) reduction using a glassy carbon electrode of OS3 (FIS3MN), FIS3MOE, and FIS3MOEN in the presence of IM LiPFe.

[0030] FIG. 3 is a graph depicting the effect of the nitrile-esters FIS3MEN and FIS3MOEN cell cycling in a NMC111 (lithium nickel manganese cobalt oxide, LiNii / sMni / sCoi / sOz) / graphite cell at 4.3V to 3.0V on cell cycle performance. The experiment was run at 70°C and 30°C. The electrolytes contained EC / DEC in a 3 / 7 ratio with IM LiPFg. A 2% vinylene carbonate (VC) electrolyte was used at the control. The cells were discharged at a rate of 1C and charged at a rate of C / 2.

[0031] FIG. 4 is a duplicate run of the cell cycling experiment shown in Fig. 3, but limited to 150 charge / discharge cycles.

[0032] FIG. 5 is a graph depicting the effect of OS3 (Fl S3MN) and nitrile-esters FI S3MEN and FIS3MOEN on 70°C cycling resistance in a NMCl l l / graphite cell. The cell was cycled from 4.3V to 3.0V. All electrolytes contained EC / DEC in a 3 / 7 ratio with IM LiPFg. The cells were discharged at a rate of 1C and charged at a rate of C / 2. Tested samples include 5% OS3, 20% OS3, 2% FIS3MOEN, and 2% FIS3MEN.

[0033] FIG. 6 is a graph depicting the effect of the nitrile-esters FIS3MEN and FIS3MOEN cell cycling in a NMCl l l / graphite cell at 4.3V to 3.0V on cell cycle performance. The experiment was run at 30°C and 70°C. The electrolytes contained EC / DEC in a 3 / 7 ratio with IM LiPFg. The cells were discharged at a rate of 1C and charged at a rate of C / 2.

[0034] FIG. 7 is a graph depicting the effect of FIS3MOE and nitrile-esters FIS3MOEN and FIS3MN on cell cycling at 30°C and 70°C. All data gathered at a discharge cycle from 4.3V to 3.0V using a NMC111 / graphite. All electrolytes contained EC / DEC in a 3 / 7 ratio with IM LiPFg. The cells were discharged at a rate of 1C and charged at a rate of C / 2.

[0035] DETAILED DESCRIPTION

[0036] Numerical ranges as used herein are intended to include every7number and subset of numbers contained within that range, whether specifically disclosed or not. Further, these numencal ranges should be construed as providing support for a claim directed to any number or subset of numbers in that range. For example, a disclosure of from 1 to 10 should be construed as supporting a range of from 2 to 8, from 3 to 7, from 5 to 6, from 1 to 9, from 3.6 to 4.6, from 3.5 to 9.9, and so forth.

[0037] All references to singular characteristics or limitations of the present invention shall include the corresponding plural characteristic or limitation, and vice-versa, unless otherwise specified or clearly implied to the contrary7by the context in which the reference is made. The indefinite articles “a” and “an” mean “one or more.” The word “or” is used inclusively and should be read “and / or.”

[0038] All combinations of method steps as used herein can be performed in any order, unless otherwise specified or clearly implied to the contrary by the context in which the referenced combination is made. The methods of the present disclosure can comprise, consist of, or consist essentially of the essential elements and limitations of the method described herein, as well as any additional or optional ingredients, components, or limitations described herein or otherwise useful in organic chemistry. The disclosure provided herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.

[0039] It is understood that the compounds and compositions disclosed herein are not confined to the particular construction and arrangement of parts herein illustrated and described, but embraces such modified forms thereof as come within the scope of the claims.

[0040] The present disclosure describes organosilicon compounds for use as electrolyte solvents in electrochemical devices. The compounds described have two or more polar groups attached to the silicon. The OS compounds described herein can be used as liquid electrolyte solvents that replace the carbonate based solvent system in traditional Li-ion batteries. The OS-based solvents provide significant improvements in performance and abuse tolerance in Li-ion batteries, including increased thermal stability for longer life at elevated temperatures, increased electrolyte flash points for improved safety, increased voltage stability to allow use of high voltage cathode materials and achieve higher energy' density, reduced battery failure rates for consistency with the requirements for large scale Li batteries used in EDV and grid storage applications, and compatibility with materials currently in use in Li-ion batteries for ease of adoption in current designs. Our experiments have shown improvement in cycling stability and reduced gassing when the multifunctional organosilanes are included in the electrolyte.

[0041] Disclosed herein are compounds of Formula !: (Formula I) wherein:

[0042] “a” is an integer from 1 to 4;

[0043] “b” is an integer from 1 to 3;

[0044] "c,” “d,” and "e” are each independently an integer from 0 to 3;

[0045] •‘a” + “d” < 4; each R is independently selected from halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alky l, alkenyl, and alkynyl; each R3and R5is independently selected from the group consisting of halo, Ci-6 linear or branched alky l, alkenyl, and alkynyl, Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl, (Formula II); each R1, R2, R4, and R6is independently selected from C1-15 linear or branched alkylene and C 1-15 halo-substituted, linear or branched alkylene; each X is independently an organic polar group selected from moieties having a valency of 2 to 4 in Group A; each Y and Z is independently an organic polar group selected from Group A or is R

[0046] — !— Si - R

[0047] R (Formula III); and Group A is an organic polar group selected from the group consisting of:

[0048] wherein a curved bond denotes a divalent -(CH2)2-6-(alkylenyl) bridging moiety.

[0049] As used herein, the term "organic polar group." “organic polar substituent" and “organic polar moiety” are used interchangeable. The terms explicitly include, but are not limited to the functional groups as listed in Group A.

[0050] In Formula I, the integer “a” represents the number of silicon-substituted moi eties containing the X and Y groups, while the integer “d” represents the number of silicon- substitute moieties containing the Z group. As “a” ranges from 1 to 4, and “d” ranges from 0 to 3, the compounds include at least one silicon-substituted moiety containing the X and Y groups. In preferred versions, at least one of the arms containing the X and Y groups includes both X and Y as organic polar groups capable of coordinating with Li+ions.

[0051] The integers “b,” “c,” and “e” correspond to the number of substituents attached to the X, Y, and Z groups, respectively, which are determined by the valency of the respective X, Y, and Z group.

[0052] In certain versions of the compounds, X, Y, and Z are organic polar groups capable of coordinating with Li+ions.

[0053] In certain versions of the compounds, when X, Y, and Z are organic polar groups with a valency of two or higher, they contain multiple substitution sites. The substitutions can be silicon atoms (as shown, for example, in Formula II or III), thereby allowing for multiple silicon atoms to be bonded to the X, Y, and Z groups via spacer groups (e g., R2and R6).

[0054] In all versions of the compounds and compositions, “halogen,” includes fluoro, chloro, bromo, and iodo. Fluoro and chloro are the preferred halogen substituents. The term “lithium-containing salt’’ explicitly includes, but is not limited to, LiC IO4-

[0055] L1BF4, LIASF6, LiPF6, L1CF3SO3, LI(CF3SO2)2N, LI(CF3SO2)3C, LIN(SO2C2F5)2, LiN(SO2F)2, lithium alkyl fluorophosphates, lithium bis(chelato)borates, and LiTFSI (bis(trifluoromethane)sulfonimide lithium salt).

[0056] For illustrative purposes only, the compounds disclosed herein may have the following exemplary structures:

[0057] The above structures are all depicted with '‘a” as 1 , “d” as 0, and one R as fluorine in Formula I. This is for purposes of brevity only. The analogous compounds having different silicon substituents, internal and / or terminal polar moieties, or additional silicon atoms, as described above, are explicitly encompassed within the scope of the disclosure. Likewise, while the halogenated compounds are illustrated as fluorinated compounds, analogous compounds having other halogen substituents (chlorine, bromine, and / or iodine) in place of fluorine are also explicitly included within the scope of the present disclosure.

[0058] The compounds listed above have been given short-hand designations, where “Fl” represents one fluoro substituent of silicon, "S3” represents a C3 alkylene spacer between the silicon atom and the X moiety, and "MEN” and “MOEN” represent the polar group moieties attached to the C3 alkylene spacer.

[0059] As can be seen, a number of these compounds are bifunctional, containing functional groups such as esters and a nitrile in the same arm. See, for example, the above structures for FIS3MEN and FIS3MOEN. It has been found that organosilicon compounds in this class are very beneficial for use in electrolytes in lithium-ion batteries due to their enhanced thermal stability' and improved electronic performance. For example, it was found that compounds disclosed therein having one of the following side groups had markedly improved thermal stability when formulated into an electrolyte composition containing fluoroethylene carbonate (FEC) and 1 M LiPFe:

[0060] A number of organosilicon compounds having a single organic polar group attached to the silicon atom were also evaluated along with the disclosed compounds to confirm the advanced characteristics of the latter. These comparison compounds follow a similar shorthand designation and have the following structures:

[0061] The following examples are provided to further illustrate the methods of synthesizing the compounds described herein and to demonstrate the properties and advantages of exemplary compounds. These examples are not intended to limit the scope of the disclosure as set forth in the appended claims.

[0062] EXAMPLES

[0063] Methods to make the compounds disclosed herein are best shown by examples of representative compounds. The analogous compounds can be fabricated using appropriate starting materials to yield the desired functional groups.

[0064] Synthesis of FIS3MEN:

[0065] FIS3MEN

[0066] Allyl cyanoacetate (CAS No. 13361-32-5; MilliporeSigma, Billerica, MA; catalog no. 360961) was mixed with few drops of Karstedt's catalyst and heated to 70°C. One (1) molar equivalent of dimethylchlorosilane was added dropwise to the flask and left stirred and kept at the same temperature overnight. The intermediate CHS3MEN was not purified and the crude product was fluorinated. Aqueous HF, NH4HF2 and SbF? were used to fluorinate the intermediate successfully. However, SbF? was preferred because the purification was easier; NH4HF2 caused solid formation during distillation and aqueous HF gave better yields but required separation of water. The crude FIS3MEN was purified by careful distillation because it decomposes easily if overheated, and then dried by azeotropic distillation with dimethyl carbonate (b.p. 80-90 °C at 0.5 Torr). Synthesis of FIS3MOEN:

[0067] Five (5) equivalents of water in the form of concentrated HCI (35% by mass) were added to 4-(fluorodimethylsilyl)butanenitrile (FIS3MN; see U.S. Pat. No. 9,437,371, issued September 6, 2016, incorporated herein by reference) and the mixture was left refluxing for 16 hours. A few drops of sulfuric acid were added to promote complete hydrolysis of the nitrile. (N.B., unreacted 4-(fluorodimethylsilyl)butanenitrile cannot be removed by distillation.) After reaction, the mixture was filtered to remove NH4CI and the organic and aqueous phases were separated. This carboxylic acid intermediate was dried by azeotropic distillation with toluene, and then it was distilled under vacuum (b.p. 80°C at 0.5 torr) to produce dry carboxylic acid. This acid was heated to 80°C and thionyl chloride was added dropwise via syringe, then left stirring overnight at room temperature. The acid chloride intermediate was distilled under vacuum (b.p. 30°C at 0.3 torr). The acid chloride silane was added dropwise to a mixture of one molar equivalent of 3-hydroxypropionitrile and 1.05 molar equivalents of triethylamine, dissolved in THF and cooled in an ice bath. A slight excess of triethylamine was used to ensure complete reaction. The final product was filtered, distilled under vacuum (b.p. 100 °C at 0.3 torr), rinsed with mild (~5%) HF solution, distilled again under vacuum, and then dried by azeotropic distillation with toluene to obtain pure and dry F 1 S3MOEN.

[0068] Determination of the Electrochemical Stability of Organosilicon Materials:

[0069] Computational chemistry methods were used to calculate electrochemical properties of various organosilicon molecules. The GAMESS program was used to model Density Function Theory (DFT) molecular orbital calculations. (“GAMESS” is acronym for “General Atomic and Molecular Electronic Structure System." It is a general ab initio quantum chemi stry software package developed by the Gordon Research Group of Iowa State University. See Schmidt et al. “General Atomic and Molecular Electronic Structure System,” J. Comput. Chem. 1993, 14, 1347-1363. It can be obtained at: msg.ameslab.gov / GAMESS / download.html.) The LUMO (lowest unoccupied molecular orbital) and HOMO (highest occupied molecular orbital) energy levels, which correlate to the reduction and oxidation potentials of compounds, respectively, were calculated at the B3LYP / DZV level. Table 1 shows LUM0 / H0M0 calculations of four of the subject compounds: FIS3MN, FIS3MEN, FIS3MOEN, and FIS3MOE. The oxidation potential ranking order, based on the highest to lowest HOMO levels, is FIS3MN, FIS3MEN, FIS3MOEN, and FIS3MOE. The reduction potential ranking order, based on highest to lowest LUMO levels, is FIS3MN, FIS3MOE, FIS3MOEN, and FIS3MEN.

[0070] Table 1. HOMO, LUMO, and window energy levels of selected compounds computed using GAMESS.

[0071] The oxidative stability of electrolytes containing organosilicon solvents was determined using linear sweep voltammetry (LSV) or cyclic voltammetry (CV) in a 3- electrode cell. A platinum microelectrode was used as the working electrode with lithium metal as both the counter and reference electrode. The potential of the system was increased from the open circuit voltage (OCV) to 6 or 8 V (vs. Li / Li+) at a scan rate of 10 mV / s. The resulting current density (mA / cm2) was recorded at each potential with a higher current indicating an oxidative reaction (i.e., lower oxidative stability). For the linear sweep voltammetry, 8V was used as a final potential to evaluate the fundamental oxidative stability of the material across a wider voltage range. For the cyclic voltammetry, 6V was used to evaluate the material across multiple scans under potentials more relevant to traditional battery applications. Multiple scans were conducted in the cyclic voltammetry experiments to determine the reversibility / irreversibility of any reactions observed.

[0072] The reductive stability of electrolytes containing organosilicon solvents was determined using linear sweep voltammetry (LSV) in a 3-electrode cell. A glassy carbon electrode was used as the working electrode with lithium metal as both the counter and reference electrode. The potential of the system was decreased from the open circuit voltage (OCV, typically 3 V) to 0.1V (vs. Li / Li+) at a scan rate of 10 mV / s. The resulting current density7(mA / cm2) was recorded at each potential with a greater current indicating a reduction reaction (i.e., lower reductive stability). Two scans w ere conducted to evaluate if the reductive processes were reversible or irreversible (i.e., passivating).

[0073] Determination of Thermal Stability of Neat Solvents & Formulated Electrolytes:

[0074] The thermal stability of the organosilicon solvents within electrolyte formulations are determined as follows: Approximately 1.0 mL of liquid sample is sealed in a Teflon liner under an Argon environment. The liner is sealed inside an NMR tube under vacuum. The samples are stored in a 100°C oven for a set number of days and / or months. Any decomposition products are detected and identified at low levels using nuclear magnetic resonance (NMR) spectroscopy. A quantitative analysis of the decomposition of solvents, salts, and additives is conducted. Multiple nuclei may be examined to fully analyze all components of the system, including the organosilicon solvent, any carbonate co-solvents, all additives, and the lithium salt (if present).

[0075] Preparation of Electrolytes:

[0076] Blending of electrolytes is completed inside a moisture-free (< 5ppm) and oxygen- free (< 20ppm) argon glove box. All electrolyte components, including solvents, salts, and additives are properly dried before blending and are stored in the glove box. Solvent moisture is monitored periodically by Karl Fischer measurement to ensure moisture levels are maintained at < 20ppm. Generally, solvents are weighed first into a separate vial and mixed until homogeneous. 70% of the solvent is added to a volumetric flask. Lithium (or other) salt is added slowly and stirred by magnetic stir bar until completed dissolved. Any other additives (i.e. VC, LiBOB) are then added slowly and stirred until the solution is homogeneous. The stir bar is removed and a portion of the remaining solvent is added to complete the volumetric requirement. The stir bar is placed back into the volumetric flask and the electrolyte is stirred until homogeneous. After blending is complete, the electrolyte is dispensed into a dried vial or alternate container for storage.

[0077] Results:

[0078] Fig. 1 is a graph depicting oxidation using a platinum electrode for OS3 (FIS3MN), FIS3MOE, and FIS3MOEN in the presence of IM LiPFe. As shown in Fig. 1, the oxidation peaks (4.5V and 5.3 V) of FIS3MOEN are earlier than the feature peak of FIS3MN (5.6V). Figs. 2A and 2B show the results of electrochemical reduction testing for the same three compounds: OS3, FIS3MOE, and FIS3MOEN, using a glassy carbon electrode. Fig. 2A shows the results of the first cycle. Fig. 2B shows the results of the second cycle. The figures show the very strong reduction behavior of FIS3MOEN. FIS3MOEN does not passivate at the electrode surface.

[0079] Fig. 3 depicts the results of cell cycling using cells comprising FI S3MOEN and FIS3MEN, at both 30°C and 70°C. The cell was a conventional NMC111 (lithium nickel manganese cobalt oxide, LiNi i sMrii sCoi sCE) / graphite cell and was cycled from 4.3V to 3.0V with a 1C discharge and a C / 2 charge for 200 cycles. The electrolytes contained EC / DEC in a 3 / 7 ratio with IM LiPF6. A 2% vinylene carbonate (VC) electrolyte was used as the control. The cell including an electrolyte comprising 2% FIS3MOEN cycled very well at 70°C. The electrolyte containing 2% F1S3MEN showed significant fade at both 30°C and 70°C. Fig. 4 confirms these results. Fig. 4 is a duplicate run of the cell cycling experiment shown in Fig. 3, but limited to 150 charge / discharge cycles. Again, the cell comprising a 2% FIS3MOEN electrolyte cycled very well at 70°C. The electrolyte containing 2% FIS3MEN showed significant fade at both 30 °C and 70°C.

[0080] Fig. 5 is a graph depicting the effect of nitrile-esters FIS3MOEN and FIS3MEN on 70°C cycling resistance in a NMC111 / graphite cell. The cell was cycled from 4.3V to 3.0V. All electrolytes contained EC / DEC in a 3 / 7 ratio with IM LiPFg, and one of 5% OS3, 20% OS3, 2% FIS3MOEN, and 2% FIS3MEN. As shown in the figure, the cell containing a 2% FIS3MOEN electrolyte showed similar impedance growth during 70°C cycling as did OS3. The impedance, though, for the cell containing a 2% FIS3MEN electrolyte was significantly higher.

[0081] Fig. 6 is another graph depicting the effect of the nitrile-esters FISsMOEN and FIS3MEN cell cycling in a NMC111 / graphite cell at 4.3V to 3.0V on cell cycle performance. The experiment was run at 30°C and 70°C. The electrolytes contained EC / DEC in a 3 / 7 ratio with IM LiPFg. Again, the cell containing a 2% FIS3MOEN electrolyte is cycling well at 70°C. The cell containing a 2% FIS3MEN electrolyte shows significant fade at both 30°C and 70°C.

[0082] Fig. 7 compares the cell cycling performance of a 2% FIS3MOEN electrolyte, a 2% FIS3MN electrolyte and a 5% FIS3MOE electrolyte. Data were gathered at a discharge cycle from 4.3V to 3.0V using a NMC1 11 / graphite; 1C discharge, C / 2 charge for 150 cycles. All electrolytes contained EC / DEC in a 3 / 7 ratio with IM LiPFg. As shown in the figure, FIS3MOEN cycling stability' improved over FIS3MOE and was similar to FIS3MN. Table 2 shows the physical properties of the nitril-esters FIS3MOEN and FI S3MEN, along with seven other organosilanes. The compounds were evaluated both in their neat form and when formulated as electrolytes containing IM LiPFe, tested at 30 °C. Electrolyte properties are shown for two formulations: without co-solvent and with 20% ethylene carbonate (EC) as co-solvent. FIS3MOEN and FIS3MEN exhibit excellent flash points and high boiling points (BP), indicating their superior thermal stability and suitability for use in high-temperature or abuse-tolerant electrolyte systems.

[0083] Table 2. Physical Properties of Organosilanes Tested. * Decomposition temperature < BP

[0084] See above for the structures of the various organosilanes noted in Table 2.

Claims

CLAIMSWhat is claimed is:

1. A compound of Formula I:(Formula I) wherein:“a” is an integer from 1 to 4;“b” is an integer from 1 to 3;“d,” and "‘e” are each independently an integer from 0 to 3;“a” + “d” < 4; each R is independently selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl; each R3and R5is independently absent or selected from the group consisting of halo, Ci- 6 linear or branched alkyl, alkenyl, and alkynyl, Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl,(Formula II); each R1, R2, R4, and R6is independently selected from the group consisting of C1-15 linear or branched alkylene and Ci-i5 halo-substituted, linear or branched alkylene, or R2is absent; each X is independently an organic polar group selected from moieties having a valency of 2 to 4 in Group A; each Y and Z is independently an organic polar group selected from Group A or is(Formula III); and wherein Group A is an organic polar group selected from the group consisting of:wherein a curved bond denotes a divalent -(CH2)2-6-( alkylenyl) bridging moiety.

2. The compound of claim 1, wherein when a single R group is present, the R is fluorine; and when two or more R groups are present, at least one R is fluorine.

3. The compound of any one of claims 1-2, wherein each X is independently selected from the group consisting of4. The compound of any one of claims 1-3, wherein when a single Y group is present, the Y is selected from Group A; and when two or more Y groups are present, at least one Y is selected from Group A.

5. The compound of claim 4, wherein each Y is independently selected from the. . „ group consisting ol6. The compound of any one of claims 1 -5, wherein “a” is 1 , "‘b” is 1 to 2, and “d” is 0.

7. The compound of claim 6, wherein "c" is 0 or 1; and when ”c" is 1, R3is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl.

8. The compound of claim 7, wherein at least one R is fluorine, and each R1and R2is independently selected from the group consisting of Ci-6 linear or branched alkylene.

9. The compound of any one of claims 1-5, wherein “a’' is 2, “b” is 1 to 2, and “d” is 0.

10. The compound of claim 9, wherein “c” is 0 or 1; and whenC'c’’ is 1, R3is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl.

11. The compound of claim 10, wherein at least one R is fluorine, and each R1and R2is independently selected from the group consisting of Ci-6 linear or branched alkylene.

12. The compound of any one of claims 1-5, wherein “a” is 3, "‘b” is 1 to 2, and “d” is 0.

13. The compound of claim 12, wherein “c’?is 0 or 1; and when “c” is 1, R3is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyd, alkenyl, and alkynyl.

14. The compound of claim 13, wherein R is fluorine, and each R1and R2is independently selected from the group consisting of Ci-6 linear or branched alkylene.

15. The compound of any one of claims 1-5, wherein “a’' is 4, “b” is 1 to 2, and “d"’ is 0.

16. The compound of claim 15, wherein “c” is 0 or 1; and when “c” is 1, R3is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alky l, alkenyl, and alky nyl.

17. The compound of claim 16, wherein each R1and R2is independently selected from the group consisting of Ci-6 linear or branched alkylene.

18. The compound of any one of claims 1-5, wherein “d” is 1 to 3, and each R4is independently selected from the group consisting of Ci-6 linear or branched alkylene.

19. The compound of claim 18, wherein “e” is 0 or 1; and when “e’‘ is 1, R5is selected from the group consisting of halo, Ci-6 linear or branched alkyl, alkenyl, and alkynyl, and Ci-6 halo-substituted, linear or branched alkyl, alkenyl, and alkynyl.

20. An electrolyte composition comprising, in combination, one or more compounds as recited in any one of claims 1-18 and a lithium-containing salt.

21. An electrochemical device comprising the electrolyte composition of claim 20.

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