Electrolyte for a battery cell, battery cell for a vehicle and method for forming an electrolyte

Abstract

Electrolyte for a battery cell, battery cell for a vehicle, and method for forming an electrolyte. The electrolyte comprises a base electrolyte. The base electrolyte comprises a primary lithium salt, a carbonate solvent, and an organic sulfate additive. The electrolyte also comprises lithium bis(fluorosulfonyl)imide (LiFSI), present in the range of 0.1 wt% to 1 wt% of the total weight of the electrolyte, a phosphite ester oxygen scavenger, present in the range of 0.01 wt% to 1.5 wt% of the total weight of the electrolyte, and fluoroethylene carbonate, present in the range of 0.5 wt% to 2.0 wt% of the total weight of the electrolyte. The base electrolyte is the remaining wt% of the total weight of the electrolyte, and the total wt% of the electrolyte is 100 wt%.

Description

[0001] Electric and hybrid electric vehicle technology is enabled by the development and use of rechargeable secondary batteries that supply energy to the vehicle's powertrain. Secondary batteries include lithium-ion batteries, which generally comprise a cathode, an anode, a separator, and an electrolyte. The cathode provides the source of lithium ions and determines the battery's capacity and average voltage. The anode stores and releases lithium ions received from the cathode when energy is needed. The separator prevents the cathode and anode from contacting and short-circuiting the battery, and the electrolyte provides a medium between the cathode and anode through which the lithium ions move.

[0002] Battery performance can be quantified by a number of properties, including energy density, power density, specific energy, specific power, charge rate, discharge rate, capacity decay, cycle life, thermal performance, and aging. Of particular interest are high-voltage performance, around 4.4 volts per cell or higher, and stability during high-temperature battery cycles at temperatures of 45°C or higher. Conventional lithium-ion battery electrolytes may exhibit relatively low high-voltage protection at high temperatures. Lithium-manganese-rich (LMR) battery electrolytes contain relatively high levels of fluorinated solvents, which enhances their stability at high voltages.However, these electrolytes release gases at high temperatures, such as oxygen, carbon monoxide, carbon dioxide, and hydrogen, due to electrolyte decomposition caused by chemical reactions between components in the electrolyte and other components in the battery cell. The gas is trapped within the battery cells and causes them to expand.

[0003] Furthermore, during the formation of lithium- and manganese-rich batteries, it is desirable to convert manganese from a layered structure to a spinel structure. Converting manganese to spinel structures increases the specific capacity. If formation takes place at room temperature, the manganese conversion continues during subsequent charge and discharge cycles, complicating the programming of the battery management system and causing other problems. Formation at higher temperatures, such as around 45 degrees Celsius, increases the manganese conversion to spinel structures but again causes electrolyte gassing.

[0004] US 2024 / 0322244A1 describes an electrolyte comprising a lithium salt composition, a solvent composition, and a diluent composition. The diluent composition includes at least one alkane compound. The at least one alkane compound is selected from (1) non-fluorinated alkane compounds characterized by a first molecular formula CpH2p+2, where p is a first integer between 5 and 20, and (2) fluorinated alkane compounds characterized by a second molecular formula CqHq1Fq2, where q is a second integer between 4 and 20, where q1 is a third positive integer, and q2 is a fourth positive integer, where q, q1, and q2 are related to each other by q1+q2=2q+2. A lithium-ion battery containing such an electrolyte is also described.

[0005] CN 1 07 275 676 A describes an electrolyte solution for a silicon-based lithium secondary battery. The electrolyte solution comprises: a non-aqueous organic solvent, a lithium salt, and an additive, wherein the additive comprises fluoroethylene carbonate, lithium difluoro(oxalato)borate, and a compound with a structure specified in the description as Formula I, where in Formula IX a P=O group, a P atom, and a B atom are represented; A1, A2, and A3 are independently selected from alkyl, silicyl, and fluoroalkyl. A silicon-based lithium secondary battery is also described. The electrolyte solution can effectively improve the battery's cycle performance at room temperature, its storage performance at high temperatures, and its discharge performance at low temperatures.

[0006] DE 10 2023 124 421 A1 describes a battery that cycles lithium ions, comprising a negative electrode and an ionically conductive electrolyte. The negative electrode contains an electroactive material that includes a silicon oxide-based material. The electrolyte comprises an organic solvent, a lithium salt, and a ternary additive system with a phosphite compound, a borate compound, and a sulfate compound.

[0007] DE 10 2021 113 877 A1 describes a lithium-ion battery with a cathode, an anode, and an electrolyte composition in contact with the cathode and the anode. The cathode comprises a manganese-rich cathode active material containing manganese alone or together with at least one element from the group consisting of cobalt and nickel, wherein the molar fraction of manganese in the cathode active material is higher than the fraction of nickel and cobalt. The electrolyte composition comprises a solvent containing sulfolane or an alkyl-substituted sulfolane in a proportion of at least 30% by weight, based on the total weight of the solvent. Furthermore, the use of the electrolyte composition in a lithium-ion battery is proposed.

[0008] DE 10 2023 121 796 A1 describes an electrode for an electrochemical cell that cycles lithium ions, comprising a porous electroactive layer and an electrolyte arranged in at least a fraction of the pores of the porous electroactive layer. The porous electroactive layer contains an electroactive material represented by: Li₂MnO₃ · (1-x)LiMO₂, where M is a transition metal selected from the group consisting of nickel (Ni), manganese (Mn), cobalt (Co), aluminum (Al), iron (Fe), and combinations thereof, and 0.01 ≤ x ≤ 0.99. The electrolyte contains a lithium salt and a first solvent containing 2,2,2-trifluoroethyl acetate (TFEA). The electrolyte may also contain a second solvent containing fluoroethylene carbonate (FEC) and / or a third solvent containing diethyl carbonate (DEC).The ratio between the first solvent, the second solvent, and the third solvent can be greater than or equal to approximately 1:1:98 to less than or equal to approximately 98:1:1.

[0009] An, F.; Zhao, H.; Zhou, W.; Ma, Y.; Li, P.: S-containing and Si-containing compounds as highly effective electrolyte additives for SiOx-based anodes / NCM 811 cathodes in lithium ion cells. In: Science Reports, 2019, Vol. 9: 14108, describes high-energy-density battery cells containing nickel-rich cathodes and silicon-based anodes.

[0010] While conventional electrolyte chemistries and other battery materials fulfill their intended purpose, the object of the invention is to provide new and improved electrolyte chemistries that offer relatively improved high-temperature performance.

[0011] The object of the invention is achieved by means of an electrolyte for a battery cell. The electrolyte comprises a base electrolyte. The base electrolyte comprises a primary lithium salt, a carbonate solvent, and an organic sulfate additive. The electrolyte also comprises lithium bis(fluorosulfonyl)imide (LiFSI), present in the range of 0.1 wt.% to 1 wt.% of the total weight of the electrolyte, a phosphite ester oxygen scavenger present in the range of 0.01 wt.% to 1.5 wt.% of the total weight of the electrolyte, and fluoroethylene carbonate present in the range of 0.5 wt.% to 2.0 wt.% of the total weight of the electrolyte. The base electrolyte is the remaining wt. percent of the total wt. percentage of the electrolyte, and the total wt. percentage of the electrolyte is 100 wt.%. The carbonate solvent comprises ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate.Ethylene carbonate is present at a volume of 20% to 30% of the total volume of the carbonate solvent. Ethyl methyl carbonate is present at a volume of 60% to 70% of the total volume of the carbonate solvent. Diethyl carbonate is present at a volume of 5% to 10% of the total volume of the carbonate solvent. The total volume percentage of the carbonate solvent is 100%.

[0012] According to one embodiment, the primary lithium salt comprises lithium hexafluorophosphate, which is present in a concentration ranging from 0.6 mol salt per liter, M, to 2.0 M in the carbonate solvent, and the lithium bis(fluorosulfonyl)imide is present in a concentration ranging from 0.01 mol salt per liter, M, to 0.2 M in the carbonate solvent.

[0013] According to another embodiment, the organic sulfate additive comprises methylenemethanedisulfonate and is present in the electrolyte in the range of 0.5 wt.% to 1 wt.% of the total weight of the electrolyte.

[0014] According to another embodiment, the phosphite ester oxygen scavenger is Tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, THFPPi.

[0015] According to a further embodiment, the base electrolyte comprises lithium hexafluorophosphate, LiPF6, present in the carbonate solvent at a concentration of 1.1 M; ethylene carbonate, EC, present at 25 volume percent of the total volume of the carbonate solvent; ethyl methyl carbonate, EMC, present at 65 volume percent of the total volume of the carbonate solvent; diethyl carbonate, DEC, present at 10 volume percent of the total volume of the carbonate solvent; and the organic sulfate additive is methylenemethanedisulfonate, present at 1 weight percent of the total weight of the electrolyte. The lithium bis(fluorosulfonyl)imide, LiFSI, is present at 0.1 weight percent of the total weight of the electrolyte, and the phosphite ester oxygen scavenger is Tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, present at 0.05 weight percent of the total weight. of the electrolyte is present, and fluoroethylene carbonate, FEC,which is present in 1 percent by weight of the total weight of the electrolyte.

[0016] According to the invention, a battery cell for a vehicle is also provided. The battery cell comprises a cathode electrode, which includes a cathode arranged on a cathode current collector; an anode electrode, which includes an anode arranged on an anode current collector; a separator positioned between the cathode and the anode; and an electrolyte that contacts the cathode, the anode, and the separator. The electrolyte comprises a base electrolyte. The base electrolyte comprises a primary lithium salt, a carbonate solvent, and an organic sulfate additive. The electrolyte also includes lithium bis(fluorosulfonyl)imide, LiFSI, present in an amount ranging from 0.1 wt% to 1 wt% of the total weight of the electrolyte, a phosphite ester oxygen scavenger present in an amount ranging from 0.01 wt% to 1.5 wt% of the total weight of the electrolyte, and fluoroethylene carbonate present in an amount ranging from 0.5 wt% to 1.5 wt% of the total weight of the electrolyte.The base electrolyte is present in a range of -% to 2.0 wt% of the total weight of the electrolyte. The base electrolyte is the remaining wt% of the total wt% of the electrolyte, and the total wt% of the electrolyte is 100 wt%. In embodiments, the electrolyte is one of the embodiments described above. The carbonate solvent comprises ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate. The ethylene carbonate is present in a range of 20 to 30 wt% of the total volume of the carbonate solvent. The ethyl methyl carbonate is present in a range of 60 to 70 wt% of the total volume of the carbonate solvent. The diethyl carbonate is present in a range of 5 to 10 wt% of the total volume of the carbonate solvent. The total wt% of the carbonate solvent is 100%.

[0017] According to one embodiment, the primary lithium salt comprises lithium hexafluorophosphate, which is present in the carbonate solvent at a concentration ranging from 0.6 mol salt per liter (M) to 2.0 M. The organic sulfate additive is methylenemethanedisulfonate. The methylenemethanedisulfonate is present in the electrolyte at a concentration ranging from 0.5 wt% to 1 wt% of the total weight of the electrolyte.

[0018] According to another embodiment, the phosphite ester oxygen scavenger is Tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite (THFPPi).

[0019] According to another embodiment, the cathode has the following composition: xLi2MnO3 - (1-x)LiMO2, where “M” is at least one of nickel, cobalt and manganese and “x” is in the range of 0 to 1.

[0020] According to another embodiment, the cathode is selected from at least one of lithium nickel manganese oxides, lithium nickel manganese cobalt oxides, lithium nickel cobalt aluminum oxides and lithium nickel cobalt manganese aluminum oxide.

[0021] According to a further embodiment, the anode comprises at least one of graphite and graphite-silicon, wherein silicon is present in the range of 0.1 wt.% to 30 wt.% of the total weight of the graphite-silicon.

[0022] According to the invention, a method for forming an electrolyte is also provided. The method comprises mixing a base electrolyte, wherein the base electrolyte comprises a primary lithium salt, a carbonate solvent, and an organic sulfate additive, with lithium bis(fluorosulfonyl)imide (LiFSI) present in an amount ranging from 0.1 wt% to 1 wt% of the total weight of the electrolyte, a phosphite ester oxygen scavenger present in a range ranging from 0.01 wt% to 1.5 wt% of the total weight of the electrolyte, and fluoroethylene carbonate present in a range ranging from 0.5 wt% to 2.0 wt% of the total weight of the electrolyte, wherein the base electrolyte is the remaining wt% of the total wt% of the electrolyte, and the total wt% of the electrolyte is 100 wt%. The carbonate solvent comprises ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate.Ethylene carbonate is present at a volume of 20% to 30% of the total volume of the carbonate solvent. Ethyl methyl carbonate is present at a volume of 60% to 70% of the total volume of the carbonate solvent. Diethyl carbonate is present at a volume of 5% to 10% of the total volume of the carbonate solvent. The total volume percentage of the carbonate solvent is 100%.

[0023] According to a further embodiment, the method further comprises introducing the electrolyte into a battery cell, charging and discharging the battery cell at temperatures in the range of 45 degrees Celsius to 80 degrees Celsius and forming a solid electrolyte interface.

[0024] The drawings described herein are for illustrative purposes only. Fig. Figure 1 illustrates a vehicle and a powertrain that includes a secondary battery. Fig. Figure 2A illustrates an exploded view of the layers of a battery cell. Fig. 2B illustrates a pouch or prismatic battery cell. Fig. Figure 2C illustrates a cylindrical battery cell. Fig. 2D illustrates a button battery cell. Fig. Figure 3 illustrates a method for forming an electrolyte and a battery cell. Fig. Figure 4 illustrates a diagram of the specific capacity of battery cells (y-axis), including various additive formulations in the electrolyte relative to the charge-discharge cycle number (x-axis). Fig. Figure 5 illustrates a diagram of the change in the thickness of battery pouch cells (y-axis), including different electrolyte formulations (x-axis).

[0025] The following description is merely exemplary. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding introduction, summary, or subsequent detailed description. It is understood that in the drawings, identical reference symbols denote identical or corresponding parts and features.

[0026] Several examples of the description, illustrated in the accompanying drawings, are now referred to in detail. Where possible, the same or similar reference symbols are used in the drawings and the description to refer to identical or similar parts or steps. The drawings are simplified and not to scale.

[0027] This description relates to an electrolyte, a vehicle battery cell comprising the electrolyte, and a method for forming the electrolyte. The electrolyte can be used in a variety of battery cell platforms, including prismatic, pouch, cylindrical, or button-shaped battery cells. The electrolyte and the battery cell can be used in batteries for electric or hybrid electric vehicles. The electrolyte comprises fluoroethylene carbonate, which is present in 2% by weight or less of the total weight of the electrolyte, and provides stability at voltages of 4.0 volts (V) or higher, such as in the range of 4.0 volts to 4.5 volts. In embodiments, the electrolyte also comprises 10% by volume or less of diethyl carbonate in the carbonate solvent.In other embodiments, the battery cell exhibits increased temperature cycle stability at temperatures of 45 degrees Celsius or more, such as in the range of 45 degrees Celsius to 80 degrees Celsius.

[0028] As used herein, the term "vehicle" is not limited to automobiles. While the technology presented here is mainly described in connection with electric and hybrid electric vehicles, the technology is not limited to electric and hybrid electric vehicles.The concepts can be used in a wide variety of applications, such as in conjunction with components used in motorcycles, mopeds, locomotives, aircraft, watercraft and other vehicles, as well as in other applications that use batteries, such as consumer electronics, building power grids and portable power plants used to supply electricity to remote construction sites, emergency power supplies and permanent power plants connected to buildings and equipment, all of which can be powered, for example, by solar or wind-powered generator systems, power grids and fuel-based power generators, such as gasoline, propane, kerosene or diesel generators and Sterling engines.

[0029] Fig.Figure 1 illustrates a vehicle 100 comprising a drive system 120. The drive system 120 generally includes an electric motor 124 and a secondary battery 126 for supplying power to the electric motor 124. Furthermore, in many embodiments, the drive system 120 includes an inverter 128 for converting the power from DC (direct current), as supplied by the battery 126, to AC (alternating current), as used by the electric motor 124. The inverter 128 may be contained within a power electronics module 130, which includes, for example, transistors and diodes for switching the power from DC to AC and vice versa.

[0030] A controller 132 is connected to the inverter 128 and is programmed to control and manage the operation of the electric motor 124 and the associated hardware, including the inverter 128. The electric motor 124 is connected to a gearbox (drive unit) 136 and a drive line 138, which transmits mechanical power and rotation to the wheels 140 of the vehicle 100. The controller 132 comprises one or more processors and tangible, non-volatile memory 134. A combustion engine may also be included in the drive system of hybrid electric vehicles.

[0031] Referring again to the electric motor 124, the electric motor 124, which is powered by the battery 126, comprises a stator 142 and a rotor 144 located inside the stator 142. The stator 142 is the stationary part of the electric motor 124. The stator 142 provides a rotating magnetic field with which the stationary magnetic field of the rotor 144 attempts to align, causing the rotor 144 to rotate, which can be referred to as the "motor operation" mode. In other applications, the rotating field (as caused by physical rotation) of the rotor 144 generates an electric current in the stator 142—this operating mode is referred to as "generation," and the electric motor 124 used in this way is called a generator. In traction motor vehicle applications, the motor operation provides motion to the vehicle 100.The generation mode takes some of the energy recovered from braking while the vehicle is in the process of stopping and stores it back in the vehicle battery 126.

[0032] It will be directed to the Fig. 2A, Fig. 2B, Fig. 2C and Fig. 2D reference is made, which illustrates an example of a secondary battery 126 for supplying an electric vehicle 100 with electricity, such as the one in Fig. 1 illustrated electric vehicle 100. As noted above, secondary batteries 126 are understood to be rechargeable batteries that can be discharged when a load is applied and recharged when an external power source is applied. Referring to the Fig. 2A, Fig. 2B, Fig. 2C and Fig.Figure 2D illustrates that a battery 126 is connected to a load 148, such as the electric motor 124. Other loads 148, however, include various systems in the vehicle 100, such as climate control systems and infotainment systems. The battery 126 comprises one or more battery cells 150 that are assembled together. The battery cells 150 can be, for example, bag-shaped, prismatic, cylindrical, or button-shaped battery cells, which are discussed further below. With reference to the Fig. 2B to 2D move Li + -ions, when a load 148 is applied to the battery 126, from the anode 158 through the separator 160 via the electrolyte 162 to the cathode 156. Equivalent electrons e - move through circuit 146 from cathode 156 to anode 158, thereby supplying voltage to load 148. During charging, Li +-Ions are transferred from the cathode 156 via the electrolyte 162 through the separator 160 to the anode 158 when an external voltage is applied and can be stored in the anode 158.

[0033] Each battery cell contains 150 cells, such as those in the Fig. 2B, Fig. 2C and Fig.The 2D illustrated battery cell generally comprises a cathode current collector 152, a cathode 156 arranged on the cathode current collector 152, an anode current collector 154, an anode 158 arranged on the anode current collector 154, a separator 160 positioned between the cathode 156 and the anode 158, and an electrolyte 162. While the illustrated battery cells 150 comprise an anode 158 (and an anode current collector 154) and a cathode 156 (and a cathode current collector 152), the battery cell 150 can alternatively comprise two or more cathodes 156 (and one or more cathode current collectors 152) and one or more anodes 158 (and one or more anode current collectors 154). In further alternative embodiments, the battery cell 150 can comprise one or more cathodes 156 (and one or more cathode current collectors 152) and two or more anodes 158 (and two or more anode current collectors 154).In each of the above constructions, one or more separators 160 are nested between the cathodes 156 and the anodes 158 to prevent the cathodes 156 and the anodes 158 from contacting each other.

[0034] In embodiments, the battery cell 150 is of Fig.2B is configured as a pouch-like battery cell or in a prismatic battery cell. In both designs, which have multiple cathodes 156 and multiple anodes 158, separators 160 are provided between the cathodes 156 and the anodes 158. In embodiments, a ribbon-shaped separator 160 can be z-folded around each cathode 156 (and each cathode current collector 152) and around each anode 158 (and each anode current collector 154). In a pouch-like cell, tabs 164 are welded to the cathode current collectors 152 and the anode current collectors 154. Alternatively, the tabs 164 are integrally formed with the cathode current collectors 152 and the anode current collectors 154 by cutting the tabs 164 together with the cathode current collectors 152 and the anode current collectors 154 from larger sheet material. Furthermore, the cover 166 is in the form of a flexible foil bag made of aluminum or another material.Prismatic cells, on the other hand, include terminals to which the cathode current collectors 152 and the anode current collectors 154 are connected, and the cover 166 is formed from a relatively rigid housing, typically in the form of a cuboid. The tabs 164, or terminals, which are connected to the cathode current collectors 152 of several battery cells 150, are interconnected, for example, by a busbar 168 (see ). Fig. 2A) or another electrical connection, and the tabs 164 or terminals connected to the anode current collectors 154 of several battery cells 150 are connected to each other, such as by a busbar 169 (see Fig. 2A) or another electrical connection.

[0035] Alternatively, the battery cell 150 from Fig.2C is configured as a cylindrical battery cell 150. In this construction, the cathode current collector 152, the anode current collector 154, the cathode 156, the anode 158, and one or more separators 160 are in the form of long strips rolled into a cylinder or a jelly roll. Like the prismatic cell, the cover 166 is formed from a relatively rigid housing made of aluminum or another material. Tabs 164 are welded to the cathode current collector 152 and the anode current collector 154. The tabs 164, which are connected to the cathode current collectors 152 of several battery cells 150, are interconnected, for example, by a busbar 168 (see Fig. 2A) or another electrical connection, and the tabs 164 or terminals connected to the anode current collectors 154 of several battery cells 150 are connected to each other, such as by a busbar 169 (see Fig. 2A) or another electrical connection.

[0036] In alternative embodiments, the battery cell 150 is packaged in a button cell, as in Fig. Illustrated in 2D. In this construction, the cathode current collector 152, the anode current collector 154, the cathode 156, the anode 158, and one or more separators 160 in the form of discs are sandwiched together in the button-like packaging that forms the cover 166, which includes a cap 170 and a can 172. A spring washer 174 may be included between the cathode current collector 152 and the cap 170. Before the cap 170 is attached to the can 172, electrolyte 162 is added to the battery cell 150. The cap includes terminals 164 for the anode 158 and the cathode 156.

[0037] In the various types of battery cells 150 mentioned above, the cathode current collector 152 and the anode current collector 154 are formed from conductive materials. In embodiments, the cathode current collector 152 comprises aluminum. Alternatively or additionally, the cathode current collector 152 may comprise carbon-coated aluminum and stainless steel. In embodiments, the anode current collector 154 comprises copper. Alternatively or additionally, the anode current collector 154 may comprise nickel, stainless steel, and titanium. The current collectors 152 and 154 are illustrated as being in the form of a foil; however, it is understood that other forms, such as a mesh, are possible. In embodiments, a foil cathode current collector 152 and a foil anode current collector 154 are impermeable to gas.The cathode current collector 152 has a thickness in the range of 5 micrometers to 50 micrometers, including all values ​​and ranges within this range, such as the range of 5 micrometers to 25 micrometers. The anode current collector 154 has a thickness in the range of 4 micrometers to 50 micrometers, including all values ​​and ranges within this range, such as the range of 4 micrometers to 25 micrometers.

[0038] The cathode 156 includes a source of lithium ions (Li +) and can be subjected to reversible insertion or deposition of lithium ions, thereby determining, for example, the capacity and average voltage of a battery. In embodiments, the cathode material comprises a lithium- and manganese-rich material with the formulation xLi2MnO3 - (1-x)LiMO2, where "M" is at least one of nickel, cobalt, and manganese, and "x" is a fraction indicating the relative proportion of the Li2MnO3 phase within the structure, ranging from 0 to 1. Additionally or alternatively, the cathode material comprises lithium nickel manganese oxides, lithium nickel manganese cobalt oxides, lithium nickel cobalt aluminum oxides, and lithium nickel cobalt manganese aluminum oxide. In embodiments, the lithium nickel manganese cobalt oxides have the formula LiNi a Mn b Co c O2, where the sum of a, b and c is 1, such as LiNi 0,33 Mn 0,33 Co 0,33 O2 (NMC111), LiNi 0,5 Mn 0,3 Co0,2 O2 (NMC 523), LiNi 0,6 Mn 0,2 Co 0,2 O2 (NMC 622), LiNi 0,7 Mn 0,2 Co 0,1 O2 (NMC 721), LiNi 0,75 Mn 0,25 O2 (NM75) and LiNi 0,8 Mn 0,1 Co 0,1 O2 (NMC 811). In further embodiments, the lithium manganese oxide cathode, Li2Mn2O4, is a spinel-type cathode.

[0039] In embodiments, the cathode material is deposited on the cathode current collector 152 at a density in the range of 1.5 milliampere-hours per square centimeter to 5 milliampere-hours per square centimeter, including all values ​​and ranges therein, such as from 1.7 milliampere-hours per square centimeter to 3.5 milliampere-hours per square centimeter. The cathode material comprises particles having a particle size (largest linear cross-section, as measured by optical microscopy) in the range of 5 nanometers to 50 micrometers, including all values ​​and ranges therein.

[0040] The cathode electrode 151, which includes both the cathode current collector 152 and the cathode 156, has a thickness in the range of 10 micrometers to 500 micrometers, including all values ​​and ranges therein, when the cathode material is formed on one side of the cathode current collector 152. When the cathode material is formed on both sides of the cathode current collector 152, the cathode electrode has a thickness in the range of 30 micrometers to 1050 micrometers, including all values ​​and ranges therein, for a double-sided cathode electrode, such as in the range of 205 micrometers to 500 micrometers.

[0041] The anode 158 comprises materials that can be subjected to reversible insertion or intercalation of lithium ions at a lower electrochemical potential than the cathode material 156, such that an electrochemical potential difference exists between the anode 158 and the cathode 156. In embodiments, the anode material comprises graphite, optionally in combination with a silicon compound. In embodiments, the graphite comprises at least one pure graphite and one surface-modified synthetic graphite. In further embodiments, the graphite is modified with at least one hard carbon (also referred to as non-graphitizing carbon or coal) and one soft carbon (also referred to as graphitizing carbon). In further embodiments, the graphite has an average particle size D50 between 6 micrometers and 20 micrometers.Furthermore, the graphite exhibits a surface area of ​​1 square meter per gram to 120 square meters per gram, as measured by Brunauer-Emmett-Teller (BET) surface analysis. The graphite has a gram weight percent in the range of 50 wt% to 100 wt%. Additionally, the graphite's tapping density ranges from 0.5 grams per cubic centimeter to 1.5 grams per cubic centimeter, encompassing all values ​​and ranges within this range.

[0042] In further embodiments, the anode material comprises graphite, present in the range of 70 wt.% to 99.9 wt.% of the total weight of the anode, including all values ​​and ranges therein, and a silicon compound, present in the range of 0.1 wt.% to 30 wt.% of the total weight of the anode, including all values ​​and ranges therein, such as 0.1 wt.% to 30 wt.%, wherein the total weight percentage of the anode is 100%. In further embodiments, the anode material comprises graphite, present in the range of 80 wt.% to 95 wt.% of the total weight of the anode, including all values ​​and ranges therein, and the silicon compound, present in the range of 5 wt.% to 20 wt.% of the total weight of the anode, including all values ​​and ranges therein, wherein the total weight percentage of the anode is 100%.The silicon compound comprises at least one of silicon, silicon oxide (SiOx, where x is in the range of 1 to 2), lithiated silicon oxide (LSO), silicon carbon (SiC), and a silicon alloy, such as silicon-titanium (SiTi), silicon-niobium (Si-Nb), and silicon-aluminum (Si-Al). Lithiated silicon oxide has the formula Li. y SiO xwhere x is between 0 and 2 and y is between 0 and 1. The average particle size of the lithiated silicon dioxide is 3 micrometers < D50 < 20 micrometers. The lithiated silicon dioxide also exhibits a surface area of ​​0.5 square meters per gram to 10 square meters per gram, as measured by Brunauer-Emmett-Teller (BET) surface analysis. Furthermore, the knock density of the lithiated silicon dioxide is in the range of 0.8 grams per cubic centimeter to 1.5 grams per cubic centimeter, including all values ​​and ranges therein. The silicon content in the silicon carbide is in the range of 30 wt% to 60 wt% of the silicon carbide, including all values ​​and ranges therein. The average particle size of the silicon carbide is 3 micrometers < D50 < 20 micrometers. Silicon carbide also has a surface area of ​​0.5 square meters per gram to 10 square meters per gram, as measured by Brunauer-Emmett-Teller (BET) surface analysis.Furthermore, the TD density of the silicon carbide is in the range of 0.6 grams per cubic centimeter to 1.5 grams per cubic centimeter, including all values ​​and ranges therein. Additionally or alternatively, the anode material comprises one or more of the following: tin oxide, aluminum, indium, zinc, germanium, and titanium oxide, as well as any combination thereof.

[0043] In embodiments, the anode material on the anode current collector 154 is deposited at a density in the range of 1.65 milliampere-hours per square centimeter to 5.5 milliampere-hours per square centimeter, including all values ​​and ranges therein, such as from 1.87 milliampere-hours per square centimeter to 3.85 milliampere-hours per square centimeter. Furthermore, the density after pressing of the anode material is in the range of 1.3 grams per cubic centimeter to 2 grams per cubic centimeter, including all values ​​and ranges therein, such as from 1.5 grams per cubic centimeter to 1.7 grams per cubic centimeter.

[0044] In embodiments, the anode 158 has a thickness in the range of 10 micrometers to 550 micrometers, including all values ​​and ranges therein. In embodiments, the anode 158 is applied to the anode current collector 154, with a coating being formed on the anode current collector 154 using a deposition process, such as a slurry-based process, a hot rolling process, extrusion, or additive manufacturing. The combined anode 158 and the combined anode current collector 154 provide an anode electrode (153) to which further reference is made.

[0045] The separator 160 is a porous material formed from an electrically insulating material that prevents the cathode 156 and the anode 158 from contacting the circuit and potentially short-circuiting. The separator 160 is sandwiched between the cathode 156 and the anode 158, or at least partially enclosed, thereby allowing the passage of lithium ions and the electrolyte 162 through the pores of the separator 160. The separator 160 can comprise a composite material and / or a polymer material and / or a nonwoven material. In embodiments, the separator comprises at least one material selected from the group consisting of polyethylene, polypropylene, polyamide, polytetrafluoroethylene, polyvinylidene fluoride, and polyvinyl chloride. Furthermore, the separator 160 can be filled, i.e., comprise one or more fillers dispersed therein, wherein the one or more fillers comprise materials such as glass fibers, nonwovens, or woven fabrics.In additional or alternative embodiments, the separator 160 can comprise at least one thermally stable, porous polymer coating and / or a ceramic coating such as an aluminum oxide coating. The coating is arranged on one or more surfaces of a porous polymer film, the polymer film being selected from at least one of polyethylene and polypropylene. The separator 160 can comprise one or more layers, each layer being formed from one or more of the aforementioned materials. The separator 160 can take the form of a film or a mesh, such as a woven mesh or a slit film. In embodiments, the separator 160 has a thickness in the range of 4 micrometers to 25 micrometers, including all values ​​and ranges therein.

[0046] The electrolyte 162 provides a medium between the cathode 156 and the anode 158 through which lithium ions move. The electrolyte 162 is a liquid electrolyte that permeates the separator 160, contacts the surfaces of the cathode 156 and the anode 158, and flows into any spaces that may be present between the particles that make up the cathode 156 and the anode 158. The electrolyte 162 generally comprises a base electrolyte and an additive formulation.

[0047] The basic electrolyte comprises a primary lithium salt, a carbonate solvent, and an organic sulfate additive. The primary lithium salt comprises lithium hexafluorophosphate (LiPF6). Additionally or alternatively, the primary lithium salt may comprise one or more of the following: lithium perchlorate (LiClO4), lithium tetrachloroaluminate (LiAlCl4), lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF4), lithium tetraphenylborate (LiB(C6H5)4), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethane)sulfonylimide (LiN(CF3SO2)2), and lithium bis(trifluoromethanesulfonyl)azanide (LiTFSA). In embodiments, the primary lithium salt is present in the solvent at a concentration (moles of salt per liter of solvent) of 0.6 mol / L to 2.0 M, including all values ​​and ranges therein, such as 1.1 M. The carbonate solvent comprises a cyclic carbonate and at least two linear carbonates.The cyclic carbonate includes ethylene carbonate (EC). The cyclic carbonate is present in the range of 20% to 30% by volume of the total solvent volume, including all values ​​and ranges within this range, such as 25% by volume. The linear carbonates include ethyl methyl carbonate (EMC) and diethyl carbonate (DEC). DEC is used to increase stability at temperatures of 45°C or higher. The linear carbonate is present in the range of 60% to 80% by volume of the total carbonate solvent volume, including all values ​​and ranges within this range, such as 70% by volume.In embodiments, the ethyl methyl carbonate is present in the range of 60% to 70% by volume of the total volume of the carbonate solvent, including all values ​​and ranges therein, such as 65% by volume, and the diethyl carbonate is present in the range of 5% to 10% by volume of the total volume of the carbonate solvent, including all values ​​and ranges therein, such as 10% by volume. The use of the linear carbonates is believed to reduce the viscosity of the solvent and improve battery cell charging rate capability. The total volume percentage of the carbonate solvent is 100%. The organic sulfate additive comprises heterocyclic compounds containing at least one sulfur and at least one oxygen in the ring, wherein the ring is a five- or six-membered ring. Furthermore, at least one sulfur, if more than one is present, forms part of a sulfonyl group.In embodiments, the organic sulfate additive comprises methylenemethanedisulfonate (MMDS). Alternatively or additionally, the organic sulfate additive comprises at least one of 1,3-propanesultone, prop-1-ene-1,3-sultone, and 1,3,2-dioxathiolane-2,2-dioxide. The organic sulfate additive is present in amounts ranging from 0.1 wt% to 2.0 wt% of the total weight of the electrolyte, including all values ​​and ranges therein. Methylenemethanedisulfonate is expected to reduce solvent decomposition during cycling, thereby reducing gassing.

[0048] The additive formulation comprises lithium bis(fluorosulfonyl)imide (LiFSI), a phosphite ester oxygen scavenger, and fluoroethylene carbonate. The lithium bis(fluorosulfonyl)imide (LiFSI) is present in the electrolyte at a concentration of 0.1% to 1% by weight of the total electrolyte, including all values ​​and ranges within it. The concentration of lithium bis(fluorosulfonyl)imide (LiFSI) in the carbonate solvent is 0.01 to 0.2 M, including all values ​​and ranges within this range, such as approximately 0.1 M. The total concentration of the primary lithium salt and secondary lithium salt, if present, is up to 2.0 M, including all values ​​and ranges from 0.6 M to 2.0 M, such as approximately 1.2 M. The combination of lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI) is thought to increase the lithium ion conductivity, and the LiFSI is thought to enhance the thermal stability.The phosphite ester oxygen scavenger comprises tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite (THFPPi), present in the range of 0.01 wt% to 1.5 wt% of the total electrolyte weight. THFPPi is thought to enhance electrolyte stability at voltages of 4.0 volts or higher and also forms a relatively thin and stable cathode-electrolyte interface, with stability measured by the electrolyte's cyclic voltammogram. Furthermore, the phosphorus in the phosphite is thought to capture oxygen released from the cathode. Additionally or alternatively to THFPPi, the oxygen scavenger comprises tris(trimethylsilyl)phosphite. The additive formulation also includes fluoroethylene carbonate (FEC), which is present in the range of 0.1 wt% to 2.0 wt% of the total weight of the electrolyte, including all values ​​and ranges therein, such as 1.0 wt%.The FEC is expected to increase voltage stability at voltages of 4.0 volts or higher and protect the anode. It is understood that the total weight percentage of the electrolyte, comprising the base electrolyte, lithium bis(fluorosulfonyl)imide, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, and fluoroethylene carbonate, is 100 wt.%.

[0049] In examples, electrolyte 162 comprises a base electrolyte of 1.1 M lithium hexafluorophosphate (LiPF6) in a carbonate solvent consisting of ethylene carbonate (EC) present in 25 volume percent of the total volume of the solvent, ethyl methyl carbonate (EMC) present in 65 volume percent of the total volume of the solvent, diethyl carbonate (DEC) present in 10 volume percent of the total volume of the solvent, and methylenemethanedisulfonate present in 1 weight percent of the total weight of the electrolyte. In one example, the base electrolyte is combined with an additive formulation of lithium bis(fluorosulfonyl)imide (LiFSI), which is present in 0.1 wt% of the total weight of the electrolyte, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, which is present in 0.05 wt% of the total weight of the electrolyte, and fluoroethylene carbonate (FEC), which is present in 1 wt% of the total weight of the electrolyte.In another example, the base electrolyte is combined with an additive formulation consisting of lithium bis(fluorosulfonyl)imide (LiFSI), present in 0.1 wt% of the total weight of the electrolyte, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, present in 1 wt% of the total weight of the electrolyte, and fluoroethylene carbonate (FEC), present in 1 wt% of the total weight of the electrolyte. In another example, the base electrolyte is combined with an additive formulation of lithium bis(fluorosulfonyl)imide (LiFSI), which is present in 0.1 wt% of the total weight of the electrolyte, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, which is present in 0.05 wt% of the total weight of the electrolyte, and fluoroethylene carbonate (FEC), which is present in 1 wt% of the total weight of the electrolyte.In yet another example, the base electrolyte is combined with an additive formulation consisting of lithium bis(fluorosulfonyl)imide (LiFSI), present in 1 wt% of the total weight of the electrolyte, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, present in 1 wt% of the total weight of the electrolyte, and fluoroethylene carbonate (FEC), present in 1 wt% of the total weight of the electrolyte.

[0050] The electrolyte 162 is formed by mixing the carbonate solvent, the primary lithium salt, the organic sulfate additive, the lithium bis(fluorosulfonyl)imide, the phosphite ester oxygen scavenger, and the fluoroethylene carbonate. In embodiments, the base electrolyte (including the carbonate solvent, the primary lithium salt, and the organic sulfate ester) and the additive formulation (including the lithium bis(fluorosulfonyl)imide, the phosphite ester oxygen scavenger, and the fluoroethylene carbonate) can be combined separately, and then the base electrolyte and the additive formulation can be combined together. The electrolyte 162 can then be added to a battery cell, including one of the battery cells 150, which are located in Fig. 2B to Fig. 2D illustrations are shown. Fig.Figure 3 illustrates an embodiment of a method 300 for forming a battery cell 150 comprising the electrolyte 162. In block 302, the cathode current collector 152 with the cathode 156, the anode current collector 154 with the anode 158, and the separator 160 are assembled in a cover 166, 170, 172 of the battery cell 150. In embodiments, the cathode 156 is deposited on the cathode current collector 152 before the battery cell 150 is assembled, and the anode 158 is deposited on the anode current collector 154 before the battery cell 150 is assembled. In block 304, the electrolyte 162 is added to the battery cell 150. In block 306, the battery cell 150 is sealed. In further embodiments, the battery cell 150 at block 308 is coupled to a circuit and undergoes a formation process when current is first applied to the battery cell 150. Subsequent charging and discharging cycles can then be carried out for up to two cycles.Battery formation occurs at temperatures of 45 degrees Celsius or higher, typically in the range of 45 to 80 degrees Celsius. With charge and discharge rates ranging from 3 to 10 hours per charge and 3 to 10 hours per discharge, the charge and discharge rates are often equal. Formation at 45 degrees Celsius allows the battery cell to reach or approach its maximum capacity during formation and reduces lithium plating on the anode. As mentioned above, during battery formation, a solid electrolyte interface forms on the anode, including organic solvent reaction products with lithium. A cathode electrolyte interface also forms on the cathode, and structural changes occur in the cathode and anode materials. Examples

[0051] The following examples are provided herein for illustrative purposes.

[0052] Button cells were fabricated, including a base electrolyte and various additive formulations. The base electrolyte comprised 1.1 M lithium hexafluorophosphate (LiPF6) in a carbonate solvent consisting of ethylene carbonate (EC) present at 25% by volume of the total solvent volume, ethyl methyl carbonate (EMC) present at 65% by volume of the total solvent volume, diethyl carbonate (DEC) present at 10% by volume of the total solvent volume, and methylenemethanedisulfonate present at 1% by weight of the total electrolyte weight. The additive formulations, including lithium bis(fluorosulfonyl)imide, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, and fluoroethylene carbonate, are shown in Table 1 below. All amounts shown in the table are given as weight percent (wt%) of the total electrolyte weight. Table 1. Additive formulations formulation Lithium bis(fluorosulfonyl)imide (wt.%) Tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite (wt.%) Fluoroethylene carbonate (wt%) A 0,1 0,05 1 B 0,1 1 1 C 1 0,05 1 D 1 1 1

[0053] The button cells each comprised a graphite anode, a lithium- and manganese-rich anode with the formulation: 97% active material for the cathode and 95% active material for the anode, a spacer one millimeter thick, a wave spring 1.4 millimeter thick in a housing that includes a stainless steel cap and can.

[0054] The button cells were manufactured at 45 degrees Celsius and subjected to at least 100 charge and discharge cycles at a rate of 3 hours per charge. j Each charge and each discharge lasted 3 hours at an applied voltage ranging from 2 volts to 4.4 volts during the cycles. The specific capacity in milliampere-hours per gram was measured for each charge cycle. Fig. Figure 4 illustrates the maintenance of the specific capacity (y-axis) over the charging cycles (x-axis) for each formulation A to D.

[0055] Five pouch-shaped battery cells were fabricated and their thickness change was measured. Three of the pouch-shaped battery cells comprised the base electrolyte, each with a different additive formulation, and two of the pouch-shaped battery cells were fabricated with different electrolytes. The base electrolyte comprised 1.1 M lithium hexafluorophosphate (LiPF6) in a carbonate solvent consisting of ethylene carbonate (EC) present at 25% by volume of the total solvent volume, ethyl methyl carbonate (EMC) present at 65% by volume of the total solvent volume, diethyl carbonate (DEC) present at 10% by volume of the total solvent volume, and methylenemethanedisulfonate present at 1% by weight of the total electrolyte weight.The additive formulations, including lithium bis(fluorosulfonyl)imide, tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, and fluoroethylene carbonate, are shown in Table 2 below. All amounts shown in the table are given as weight percent (wt%) of the total weight of the electrolyte. Table 2. Additive formulations formulation Lithium bis(fluorosulfonyl)imide (wt.%) Tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite (wt.%) Fluoroethylene carbonate (wt%) A 0,1 0,05 1 B 0,1 1 1 C 1 0,05 1

[0056] The two additional electrolytes contained in the pouch cells comprised electrolyte E, which consisted of 20% by volume of fluoroethylene carbonate and 80% by volume of diethyl carbonate, and electrolyte F, which consisted of 30% by volume of ethyl carbonate, 70% by volume of dimethyl carbonate, 2% by volume of fluoroethylene carbonate, and 1% by volume of vinylene carbonate. Each pouch cell also included a lithium- and manganese-rich cathode with a 97% active material formulation, a graphite anode, a copper cathode current collector, and an aluminum anode current collector. The pouches were subjected to voltage generation from 2 volts to 4.5 volts at 45 degrees Celsius.

[0057] The thickness of the pouch cells was measured both before and after formation. The pouch cells were formed at 45 degrees Celsius and subjected to at least 100 charge and discharge cycles at a rate of 3 hours per charge and 3 hours per discharge, with an applied voltage during the cycles ranging from 2 volts to 4.4 volts. Fig. Figure 5 illustrates the increase in thickness (y-axis) for each formulation A to C, E and F. As illustrated, the pouch cells including the base electrolyte with the additive formulation showed a smaller increase in thickness compared to the other electrolyte compositions.

[0058] The electrolytes, battery cells, secondary batteries, and manufacturing processes described here offer a number of advantages. These advantages include, for example, the use of 2 wt% or less fluoroethylene carbonate. These advantages also include the use of 10 vt% or less diethyl carbonate. Furthermore, these advantages include voltage stability at 4.0 volts (V) or higher without increasing gassing. These advantages also include temperature stability at 45 degrees Celsius or higher. These advantages further include the formation of a relatively thin and stable solid electrolyte interface at the anode and cathode electrolyte interface. These advantages also include a relative increase in ionic conductivity with lithium bis(fluorosulfonyl)imide (LiFSI). These advantages also include a reduction in lithium plating, particularly after formation.These advantages also include achieving maximum or near-maximum manganese conversion during formation and simplifying battery management and battery management system programming.

[0059] As used herein, the term "controller" and related terms such as microcontroller, control module, module, controller, control unit, processor, and similar terms refer to one or more combinations of application-specific integrated circuit(s) (ASIC), field-programmable gate array (FPGA), electronic circuit(s), central processing unit(s), e.g., microprocessor(s), and associated non-volatile memory component(s) in the form of memory and storage devices (read-only memory, programmable read-only memory, direct access, hard disk, etc.). The controller 132 may also consist of multiple controllers that are in electrical communication with each other. The controller 132 may be connected to additional systems and / or controllers of the vehicle 100, enabling the controller 132 to access data such as, for example, the vehicle 100's speed, acceleration, braking, and steering angle.

[0060] A processor can be a custom or off-the-shelf processor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processor among several processors assigned to controller 132, a semiconductor composite microprocessor on a conductor basis (in the form of a microchip or chipset), a macroprocessor, a combination thereof, or generally a device for executing instructions.

[0061] The tangible, non-volatile memory 134 can, for example, include volatile and non-volatile storage in read-only memory (ROM), random-access memory (RAM), and keep-alive memory (KAM). KAM is persistent or non-volatile memory that can be used to store various operating variables while the processor is powered off. The tangible, non-volatile memory 134 can be implemented using a variety of storage devices, such as PROMs (programmable read-only memory), EPROMs (electrical PROMs), EEPROMs (electrically erasable PROMs), flash memory, or other electrical, magnetic, optical, or combination storage devices capable of storing data, some of which represents executable instructions used by the controller 132 to control various systems of the vehicle 100.

Claims

Electrolyte (162) for a battery cell (150), wherein the electrolyte (162) comprises: a base electrolyte, the base electrolyte comprising a primary lithium salt, a carbonate solvent and an organic sulfate additive; lithium bis(fluorosulfonyl)imide, LiFSI, present in the range of 0.1 wt% to 1 wt% of the total weight of the electrolyte (162); a phosphite ester oxygen scavenger present in the range of 0.01 wt% to 1.5 wt% of the total weight of the electrolyte (162); and fluoroethylene carbonate, which is present in the range of 0.5 wt% to 2.0 wt% of the total weight of the electrolyte (162), wherein the base electrolyte is the remaining wt% of the total wt% of the electrolyte (162) and the total wt% of the electrolyte (162) is 100 wt%.-%; wherein the carbonate solvent comprises ethylene carbonate, ethyl methyl carbonate and diethyl carbonate; and wherein the ethylene carbonate is present in the range of 20% to 30% by volume of the total volume of the carbonate solvent, the ethyl methyl carbonate is present in the range of 60% to 70% by volume of the total volume of the carbonate solvent, and the diethyl carbonate is present in the range of 5% to 10% by volume of the total volume of the carbonate solvent, wherein the total volume percentage of the carbonate solvent is 100%. Electrolyte (162) according to claim 1, wherein the primary lithium salt comprises lithium hexafluorophosphate present in a concentration in the range of 0.6 mol salt per liter, M, to 2.0 M in the carbonate solvent, and the lithium bis(fluorosulfonyl)imide present in a concentration in the range of 0.01 mol salt per liter, M, to 0.2 M in the carbonate solvent. Electrolyte (162) according to claim 1, wherein the organic sulfate additive comprises methylenemethanedisulfonate and is present in the electrolyte (162) in the range of 0.5 wt percent to 1 wt percent of the total weight of the electrolyte (162). Electrolyte (162) according to claim 1, wherein the phosphite ester oxygen scavenger is Tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, THFPPi. Electrolyte (162) according to claim 1, wherein the base electrolyte comprises lithium hexafluorophosphate, LiPF6, present in the carbonate solvent at a concentration of 1.1 M, ethylene carbonate, EC, present at 25 volume percent of the total volume of the carbonate solvent, ethyl methyl carbonate, EMC, present at 65 volume percent of the total volume of the carbonate solvent, diethyl carbonate, DEC, present at 10 volume percent of the total volume of the carbonate solvent, and the organic sulfate additive is methylenemethanedisulfonate, present at 1 weight percent of the total weight of the electrolyte (162), and wherein the lithium bis(fluorosulfonyl)imide, LiFSI, present at 0.1 weight percent of the total weight of the electrolyte (162), is the phosphitester oxygen scavenger. Tris(1,1,1,3,3,3-hexafluoro-2-propyl)phosphite, which is present in 0.05 wt percent of the total weight of the electrolyte (162), and fluoroethylene carbonate, FEC,which is present in 1 percent by weight of the total weight of the electrolyte (162). Battery cell (150) for a vehicle (100), comprising: a cathode electrode (151) comprising a cathode (156) arranged on a cathode current collector (152); an anode electrode comprising an anode (158) arranged on an anode current collector (154); a separator (160) positioned between the cathode (156) and the anode (158); and an electrolyte (162) contacting the cathode (156), the anode (158) and the separator (160), the electrolyte (162) comprising: a base electrolyte, the base electrolyte comprising a primary lithium salt, a carbonate solvent and an organic sulfate additive; lithium bis(fluorosulfonyl)imide, LiFSI, present in an amount ranging from 0.1 wt% to 1 wt% of the total weight of the electrolyte (162); a phosphite ester oxygen scavenger present in an amount ranging from 0.01 wt% to 1.5 wt% of the total weight of the electrolyte (162).-% of the total weight of the electrolyte (162) is present; and fluoroethylene carbonate, which is present in the range of 0.5 wt% to 2.0 wt% of the total weight of the electrolyte (162), wherein the base electrolyte is the remaining wt% of the total wt% of the electrolyte (162) and the total wt% of the electrolyte (162) is 100 wt%; wherein the carbonate solvent comprises ethylene carbonate, ethyl methyl carbonate and diethyl carbonate; and wherein the ethylene carbonate is present in the range of 20% to 30% by volume of the total volume of the carbonate solvent, the ethyl methyl carbonate is present in the range of 60% to 70% by volume of the total volume of the carbonate solvent, and the diethyl carbonate is present in the range of 5% to 10% by volume of the total volume of the carbonate solvent, wherein the total volume percentage of the carbonate solvent is 100%. Battery cell (150) according to claim 6, wherein the primary lithium salt comprises lithium hexafluorophosphate present in the carbonate solvent at a concentration in the range of 0.6 M to 2.0 M; and wherein the organic sulfate additive is methylenemethanedisulfonate present in the electrolyte (162) at a concentration in the range of 0.5 wt.% to 1 wt.% of the total weight of the electrolyte (162). A method for forming an electrolyte (162) comprising: mixing a base electrolyte, the base electrolyte comprising a primary lithium salt, a carbonate solvent, and an organic sulfate additive, with lithium bis(fluorosulfonyl)imide, LiFSI, present in an amount in the range of 0.1 wt% to 1 wt% of the total weight of the electrolyte (162), a phosphite ester oxygen scavenger present in the range of 0.01 wt% to 1.5 wt% of the total weight of the electrolyte (162), and fluoroethylene carbonate present in the range of 0.5 wt% to 2.0 wt% of the total weight of the electrolyte (162), wherein the base electrolyte is the remaining wt% of the total wt% of the electrolyte (162), and the total wt% of the electrolyte (162) is 100 wt%.-%; wherein the carbonate solvent comprises ethylene carbonate, ethyl methyl carbonate and diethyl carbonate; and wherein the ethylene carbonate is present in the range of 20% to 30% by volume of the total volume of the carbonate solvent, the ethyl methyl carbonate is present in the range of 60% to 70% by volume of the total volume of the carbonate solvent, and the diethyl carbonate is present in the range of 5% to 10% by volume of the total volume of the carbonate solvent, wherein the total volume percentage of the carbonate solvent is 100%.

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