Solvent composition for lithium metal batteries

Abstract

The battery includes a positive electrode current collector, a positive electrode, an electrolyte comprising a solvent, the solvent comprising at least one of a fluorinated organosilicon and lithium metal, and a metal current collector comprising lithium plated thereon, and a layer coated on the lithium-plated metal current collector, the layer comprising at least nitrogen and fluorine.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 414,813, filed October 10, 2022, the disclosure of which is incorporated herein by reference in its entirety. This disclosure relates generally to lithium metal batteries. More specifically, this disclosure relates to solvent compositions for lithium metal batteries. [Background technology]

[0002] The development of viable lithium-ion (Li-ion) battery technology has continued to receive increasing attention over the past decade. Such development is closely linked to the future of green technology and the decline in the use of high-carbon emitting energy sources. Summary of the Invention

[0003] The Summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood with reference to appropriate portions of the entire specification, any or all drawings, and each claim. Embodiments of the present disclosure relate to a battery comprising a positive electrode current collector; a positive electrode; an electrolyte, the electrolyte comprising a solvent, the solvent comprising at least one of a fluorinated organosilicon and lithium metal; and a metal current collector, the metal current collector comprising lithium plated thereon, wherein a layer is coated on the lithium-plated metal current collector, the layer comprising at least nitrogen and fluorine. In some embodiments, the battery is a lithium metal battery. In some embodiments, the battery is a metal battery comprising at least one of Si, Ge, Al, Ga, Bi, Ag, Sn, or Au. In some embodiments, the fluorinated organosilicon is fluoroethylene. In some embodiments, the layer is less than 1000 nm thick. In some embodiments, the layer is less than 500 nm thick. In some embodiments, the layer comprises silicon. In some embodiments, the ratio of fluorine (fluorinate) to organosilicon in the fluorinated organosilicon is from 2:1 to 30:1. In some embodiments, the solvent has a concentration greater than 20% by volume of the electrolyte.

[0004] Embodiments of the present disclosure relate to a battery that includes a positive electrode current collector, a positive electrode, an electrolyte, the electrolyte comprising a solvent, the solvent comprising at least one of a fluorinated organosilicon or lithium metal, and a metal current collector, the metal current collector consisting essentially of a non-lithium metal. In some embodiments, the battery is a lithium metal battery. In some embodiments, the battery is a metal battery comprising at least one of Si, Ge, Al, Ga, Bi, Ag, Sn, or Au. In some embodiments, the fluorinated organosilicon is fluoroethylene. In some embodiments, the ratio of fluorine to organosilicon in the fluorinated organosilicon is from 2:1 to 30:1. In some embodiments, the solvent has a concentration greater than 20% by volume of the electrolyte. An embodiment of the present disclosure is a method of forming a lithium battery, comprising the steps of: obtaining a battery, the battery comprising: a positive electrode current collector; a positive electrode; an electrolyte, the electrolyte comprising a solvent, the solvent comprising at least one of a fluorinated organosilicon or a lithium metal; and a metal current collector, the metal current collector consisting essentially of a non-lithium metal; 2and forming a coated lithium plating on a metal current collector, wherein the coated lithium plating comprises a coating layer containing at least nitrogen and fluorine.

[0005] In some embodiments, the fluorinated organosilicon is fluoroethylene. In some embodiments, the layer is less than 1000 nm thick. In some embodiments, the layer is less than 500 nm thick. In some embodiments, the layer comprises silicon. The accompanying drawings are included to provide a further understanding of the disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments, and together with the detailed description, serve to explain the principles of the present disclosure. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 illustrates a general organosilicon structure. [Figure 2] FIG. 1 is a schematic diagram of a cross-sectional view of a lithium metal cell according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a schematic diagram of a cross-sectional view of a lithium metal cell according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a schematic diagram of a cross-sectional view of a lithium metal cell according to an embodiment of the present disclosure. [Figure 5] FIG. 1 is a schematic diagram of a cross-sectional view of an anode-less coin cell according to an embodiment of the present disclosure. [Figure 6] 1 is a graph showing discharge capacity retention from cycle 1 using standard electrolyte composition 1M LiPF EC / DMC and optimized solvent replacement composition in an anode-less cell at 4 mAh / cm according to an embodiment of the present disclosure. [Figure 7] 10 is a graph showing discharge capacity from cycle 1 using lithium salt substitution in optimized OS3 / FEC solvent in an anode-less cell at 4 mAh / cm2 according to an embodiment of the present disclosure. [Figure 8]10 is a graph showing the discharge capacity retention from cycle 1 using the optimized lithium salt system 0.6 M LiTFSI 0.4 M LDFOB with various OS3 / FEC solvent ratios in an anode-less cell at 4 mAh / cm2. [Figure 9] 10 is a graph showing discharge capacity retention from cycle 1 using LiTFSI and LDFOB salt substitution in optimized OS3 / FEC solvent in an anode-less cell at 4 mAh / cm2. [Figure 10] 10 is a graph showing discharge capacity retention from cycle 1 using LiFSI salt substitution in optimized OS3 / FEC solvent in an anode-less cell at 4 mAh / cm2. [Figure 11] 10 is a graph showing the discharge capacity retention from cycle 1 using optimized and reference electrolyte compositions in anodeless cells at a lower plating capacity of 2.5 mAh / cm. [Figure 12] 10 is a graph showing the discharge capacity retention from cycle 1 using the optimized electrolyte composition in an anode-less cell at a higher plating capacity of 6.5 mAh / cm. DETAILED DESCRIPTION OF THE INVENTION

[0007] The following description provides only exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the following description of exemplary embodiments will provide those skilled in the art with an enabling description for implementing one or more exemplary embodiments. It will be understood that various changes can be made in the function and arrangement of elements without departing from the spirit and scope of the presently disclosed embodiments. Example embodiments are described below with reference to the figures. Identical, similar, or identically acting elements in various figures are identified with the same reference numerals, and repeated descriptions of these elements are omitted in part to avoid redundancy. Among these benefits and improvements disclosed, other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings. Detailed embodiments of the present invention are disclosed herein. However, it should be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Furthermore, each of the examples provided in connection with various embodiments of the present invention are intended to be illustrative and not limiting.

[0008] Throughout the specification and claims, the following terms shall take the meanings expressly associated therewith, unless the context clearly dictates otherwise. As used herein, the phrases "in one embodiment" and "in some embodiments" may, but do not necessarily, refer to the same embodiment. Furthermore, as used herein, the phrases "in another embodiment" and "in some other embodiments" may, but do not necessarily, refer to different embodiments. Thus, as described below, various embodiments of the invention can be readily combined without departing from the scope or spirit of the invention.

[0009] Also, as used herein, the term "or" is an inclusive "or" operator and is equivalent to the term "and / or" unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for based on additional unlisted factors unless the context clearly dictates otherwise. Also, as used herein, the meanings of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on." The term "based on" is not exclusive and allows for based on additional unrecited factors unless the context clearly dictates otherwise. Also, as used herein, the meanings of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on." The use of "left," "right," "inner," "outer," "above," "below," and other spatial or directional terms should not be considered limiting as the invention may contemplate various alternative orientations. All numerical values ​​used herein should be understood as modified in all instances by the term "about." The term "about" means a range of plus or minus ten percent of the stated numerical value.

[0010] Unless otherwise indicated, all ranges or ratios disclosed herein should be understood to encompass all subranges or subratios subsumed therein. Unless otherwise indicated, all ranges or ratios herein are understood to be inclusive (i.e., including both the minimum and maximum values ​​of such range or ratio). For example, a range or ratio stated as "1 to 10" is considered to include all subranges between (and including) the minimum value of 1 and the maximum value of 10. That is, all subranges or subratios beginning with a minimum value of 1 or greater and ending with a maximum value of 10 or less, such as, but not limited to, 1 to 6.1, 3.5 to 7.8, and 5.5 to 10. Currently, lithium-ion secondary battery technology utilizing metal oxide and graphite electrodes has not been able to meet growing power demands. Therefore, efforts to enable high-energy-density materials, such as lithium metal, have been at the forefront of research. Lithium metal batteries are often considered the ultimate standard for achievable energy density due to the high theoretical capacity of lithium metal (3,860 mAh / g), especially when paired with high-energy-density cathode materials. However, the realization of lithium metal battery technology is hindered by practical drawbacks stemming from nonideal lithium plating and dendrite formation, lithium metal instability, and volume changes encountered during cycling. These drawbacks present significant safety issues that hinder the commercial viability of lithium metal in secondary batteries and draw significant attention to the nuances of lithium plating and SEI formation in lithium metal batteries.

[0011] Several enabling technologies have been investigated to address the shortcomings of lithium metal batteries and realize lithium metal with high volumetric energy density. Approaches include the use of nanoparticles in electrode materials, novel lithium host structures, highly conductive solid electrolytes, and optimized liquid electrolytes. Many approaches focus on tailoring the protective solid electrolyte interface (SEI) formed during initial electrolyte reduction at the negative electrode as an enabling approach for lithium metal technology. The morphology and chemical composition of the SEI are directly affected by the electrolyte chemistry used in the system, thus affecting cell performance and lifetime.

[0012] Lithium salt and cyclic / linear carbonate-based electrolyte compositions (including lithium hexafluorophosphate salt, 1M LiPF6EC / DMC, in ethylene carbonate and dimethyl carbonate solvents) are commonly used in commercial applications, but their poor thermal and chemical stability can limit achievable capacity. While this composition provides beneficial SEI components upon LiPF6 hydrolysis, the instability of LiPF6 in carbonate solvents necessitates further electrolyte improvement. The imide-based salts lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium bis(fluorosulfonyl)imide (LiFSI) serve as promising candidates for electrolyte optimization given their more favorable reaction kinetics, improved chemical and thermal stability, and known contribution to SEI stability via LiF formation. Furthermore, LDFOB is also a potential candidate for electrolyte improvement efforts due to its unique contribution of oxalate ester reduction products to the SEI. When paired with fluorinated solvents, such as fluoroethylene carbonate (FEC) and fluoroorganosilyl-based solvents ("OS3" [Silatronix]), additional fluorinated components may be made available to the SEI architecture, enabling higher efficiency and cycle life. These fluoroorganosilyl-based solvents were initially developed to preserve the cathode interface by slowing LiPF decomposition and subsequent HF formation. To date, these compounds have not been explored as solvents for use in lithium metal battery electrolytes. Due to the unique features of this compound, including Si / F functionality and an unstable nitrile backbone, its incorporation into electrolyte compositions may reveal unique pathways for lithium plating chemistries. The downstream chemistry allows for the formation of LixSi catalytic species, which may be facilitated by the facile decomposition of the unstable nitrile backbone. Once formed, these catalytic species would enable favorable lithium metal (Li metal) nucleation and stable deposition. This reaction mechanism may shed light on future modifications of similar catalytic chemistries, thereby enabling numerous electrochemical techniques for improving lithium deposition via electrolyte optimization.

[0013] In some embodiments, the present disclosure relates to novel liquid electrolytes that enable Li-metal secondary batteries and in-situ formed anodeless Li-metal batteries. In some embodiments, by applying low-capacity lithium plating (LCP), the initial formation of SEI is amplified to observe first-cycle coulombic efficiency. This observation cannot be made when applying larger plating capacities, and the impact on dendrite formation is more easily seen. In some embodiments, utilizing electrochemical methods to directly investigate and separate solid electrolyte layer (SEI) formation from dendrite capacity decay, the present disclosure describes the possible contribution of optimized electrolytes to cycle efficiency and lifetime. In some embodiments, the present disclosure relates to a battery. In some embodiments, the battery is a metal battery. In some embodiments, the metal may include Si, Ge, Al, Ga, Bi, Ag, Sn, or Au. In some embodiments, the present disclosure relates to a lithium ion metal battery. As shown in FIG. 2 , in some embodiments, the present disclosure relates to a lithium ion metal battery 100 after fabrication in situ during battery charging. In some embodiments, the lithium ion battery includes a positive electrode current collector, a positive electrode, an electrolyte, and a metal current collector.

[0014] In some embodiments, the electrolyte comprises a solvent. In some embodiments, the present disclosure relates to solvent molecules in lithium-ion batteries. In some embodiments, the solvent comprises a cation, a nitrile, and fluorine. In some embodiments, the cation is a metal cation. In some embodiments, the metal is a metal known to alloy with lithium. In some embodiments, the metal is Ge, Al, Ga, Bi, Ag, Sn, Au, or Si. In some embodiments, the cation is a silicon cation. In some embodiments, the solvent comprises a fluorinated organosilicon. Figure 1 shows the general structure of an organosilicon. In some embodiments, the fluorinated organosilicon is fluoroethylene (FEC). In some embodiments, the solvent comprises lithium metal. In some embodiments, the ratio of fluorine to organosilicon is from 2:1 to 30:1. In some embodiments, the ratio of fluorine to organosilicon is from 5:1 to 30:1. In some embodiments, the ratio is from 10:1 to 30:1. In some embodiments, the ratio is from 15:1 to 30:1. In some embodiments, the ratio is from 20:1 to 30:1. In some embodiments, the ratio is from 25:1 to 30:1.

[0015] In some embodiments, the ratio of fluorine to organosilicon is from 2:1 to 25:1. In some embodiments, the ratio is from 2:1 to 20:1. In some embodiments, the ratio of fluorine to organosilicon is from 2:1 to 15:1. In some embodiments, the ratio is from 2:1 to 10:1. In some embodiments, the ratio is from 2:1 to 5:1. In some embodiments, the ratio of fluorine to organosilicon is 4:1 to 20:1. In some embodiments, the ratio is 12:1 to 25:1. In some embodiments, the ratio of fluorine to organosilicon is 5:1 to 15:1. In some embodiments, the ratio is 10:1 to 25:1. In some embodiments, the ratio is 10:1 to 20:1. In some embodiments, the solvent has a volume concentration greater than 20% by volume of the electrolyte. In some embodiments, the solvent has a volume concentration of 20% to 99% by volume of the electrolyte. In some embodiments, the volume concentration is 30% to 99% by volume of the electrolyte. In some embodiments, the volume concentration is 40% to 50% by volume of the electrolyte. In some embodiments, the volume concentration is 50% to 99% by volume of the electrolyte. In some embodiments, the volume concentration is 60% to 99% by volume of the electrolyte. In some embodiments, the volume concentration is 70% to 99% by volume of the electrolyte. In some embodiments, the volume concentration is 80% to 99% by volume of the electrolyte. In some embodiments, the volume concentration is 90% to 99% by volume of the electrolyte.

[0016] In some embodiments, the solvent has a volume concentration of 20% to 99% by volume of the electrolyte. In some embodiments, the volume concentration is 20% to 90% by volume of the electrolyte. In some embodiments, the volume concentration is 20% to 80% by volume of the electrolyte. In some embodiments, the volume concentration is 20% to 70% by volume of the electrolyte. In some embodiments, the volume concentration is 20% to 60% by volume of the electrolyte. In some embodiments, the volume concentration is 20% to 50% by volume of the electrolyte. In some embodiments, the volume concentration is 20% to 40% by volume of the electrolyte. In some embodiments, the volume concentration is 20% to 30% by volume of the electrolyte. In some embodiments, the solvent has a volume concentration of 30% to 90% by volume of the total mixture. In some embodiments, the volume concentration is 40% to 80% by volume of the electrolyte. In some embodiments, the volume concentration is 20% to 80% by volume of the electrolyte. In some embodiments, the volume concentration is 50% to 70% by volume of the electrolyte. In some embodiments, the volume concentration is 60% to 80% by volume of the electrolyte. In some embodiments, the volume concentration is 30% to 50% by volume of the electrolyte. In some embodiments, the volume concentration is 40% to 60% by volume of the electrolyte. In some embodiments, the volume concentration is 30% to 60% by volume of the electrolyte.

[0017] In some embodiments, lithium is deposited onto the substrate using a low area volume plating technique. In some embodiments, the solvent comprises a fluoroorganosilyl solvent (OS3). In some embodiments, the OS3 solvent comprises FEC. In some embodiments, the ratio of OS3 to FEC is 90 / 10. In some embodiments, the solvent comprises between 0.6M LiTFSI and 2M LiTFSI. In some embodiments, the solvent comprises between 1M LiTFSI and 2M LiTFSI. In some embodiments, the solvent comprises between 1.5M LiTFSI and 2M LiTFSI. In some embodiments, the solvent comprises between 0.6M LiTFSI and 1.5M LiTFSI. In some embodiments, the solvent comprises between 0.6M LiTFSI and 1M LiTFSI. In some embodiments, the solvent comprises between 1M LiTFSI and 1.5M LiTFSI. In some embodiments, the solvent comprises between 0.8M LiTFSI and 1.2M LiTFSI. In some embodiments, the solvent comprises between 1.5M LiTFSI and 1.8M LiTFSI. In some embodiments, the solvent comprises between 1M LiTFSI and 1.2M LiTFSI.

[0018] In some embodiments, the metal current collector comprises lithium plated on the metal current collector. In some embodiments, a layer is coated on the lithium-plated metal current collector. In some embodiments, the layer comprises at least one of nitrogen or fluorine. In some embodiments, the layer comprises silicon. In some embodiments, the lithium plated on the metal current collector results in improved charge / discharge efficiency in the battery and longer cycle life before failure of the battery cell. In some embodiments, the layer is less than 5000 nm thick. In some embodiments, the layer is less than 1000 nm thick. In some embodiments, the layer is less than 500 nm thick. In some embodiments, the battery has a capacity of 0.1 mAh / cm 2 ~3mAh / cm 2 In some embodiments, the battery has an areal capacity of 0.5 mAh / cm 2 ~3mAh / cm 2 In some embodiments, the battery has an areal capacity of 1 mAh / cm 2 ~3mAh / cm 2 In some embodiments, the battery has an areal capacity of 1.5 mAh / cm2 ~3mAh / cm 2 In some embodiments, the battery has an areal capacity of 2 mAh / cm 2 ~3mAh / cm 2 In some embodiments, the battery has an areal capacity of 2.5 mAh / cm 2 ~3mAh / cm 2 It has an area capacity of

[0019] In some embodiments, the battery has a capacity of 0.5 mAh / cm 2 ~2.5mAh / cm 2 In some embodiments, the battery has an areal capacity of 0.5 mAh / cm 2 ~2mAh / cm 2 In some embodiments, the battery has an areal capacity of 0.5 mAh / cm 2 ~1.5mAh / cm 2 In some embodiments, the battery has an areal capacity of 0.5 mAh / cm 2 ~1mAh / cm 2 It has an area capacity of In some embodiments, the battery has a capacity of 1.5 mAh / cm 2 ~2.5mAh / cm 2 In some embodiments, the battery has an areal capacity of 1.5 mAh / cm 2 ~2mAh / cm 2 In some embodiments, the battery has an areal capacity of 2 mAh / cm 2 ~2.5mAh / cm 2 In some embodiments, the battery has an areal capacity of 1 mAh / cm 2 ~2.5mAh / cm 2 It has an area capacity of In some embodiments, the battery is a coin cell battery. In some embodiments, the battery is an anodeless coin cell battery.

[0020] In some embodiments, a low area plating technique is used to deposit the lithium. In some embodiments, the present disclosure relates to a metal battery that may be sold by a manufacturer (i.e., prior to in-situ fabrication). In some embodiments, the metal may include Si, Ge, Al, Ga, Bi, Ag, Sn, or Au. As shown in FIG. 3, in some embodiments, the disclosure relates to a lithium ion metal battery 110 prior to in-situ fabrication. In some embodiments, the battery includes a positive electrode current collector, a positive electrode, an electrolyte, and a metal current collector. In some embodiments, the electrolyte comprises a solvent. In some embodiments, the present disclosure relates to solvent molecules in lithium-ion batteries. In some embodiments, the solvent comprises a cation, a nitrile, and fluorine. In some embodiments, the cation is a metal cation. In some embodiments, the metal is a metal known to alloy with lithium. In some embodiments, the metal is Ge, Al, Ga, Bi, Ag, Sn, Au, or Si. In some embodiments, the cation is a silicon cation.

[0021] In some embodiments, the solvent comprises a fluorinated organosilicon. In some embodiments, the fluorinated organosilicon is fluoroethylene (FEC). In some embodiments, the solvent comprises lithium metal. In some embodiments, the solvent comprises the same properties as the solvents described above. In some embodiments, the metal current collector consists essentially of a non-lithium metal, hi some embodiments, the metal current collector does not include lithium metal or any equivalent thereof. In some embodiments, the present disclosure relates to a method of forming a battery. In some embodiments, the method includes obtaining a battery. In some embodiments, the battery is a metal battery. In some embodiments, the metal may include Si, Ge, Al, Ga, Bi, Ag, Sn, or Au. In some embodiments, the disclosure relates to a lithium ion metal battery. In some embodiments, the battery includes a positive electrode current collector, a positive electrode, an electrolyte, and a metal current collector as described above.

[0022] In some embodiments, once the battery is obtained, the method includes applying a current to the battery. In some embodiments, the current is 0.1 mAh / cm 2 ~20mAh / cm 2 In some embodiments, the current is in the range of 0.5 mAh / cm 2 ~20mAh / cm 2 In some embodiments, the current is in the range of 1 mAh / cm 2 ~20mAh / cm 2 In some embodiments, the current is in the range of 2 mAh / cm 2 ~20mAh / cm 2 In some embodiments, the current is in the range of 5 mAh / cm 2 ~20mAh / cm 2 In some embodiments, the current is in the range of 10 mAh / cm 2 ~20mAh / cm 2 In some embodiments, the current is in the range of 15 mAh / cm 2 ~20mAh / cm 2 is in the range. In some embodiments, the current is 0.1 mAh / cm 2 ~15mAh / cm 2 In some embodiments, the current is in the range of 0.1 mAh / cm 2 ~10mAh / cm 2 In some embodiments, the current is in the range of 0.1 mAh / cm 2 ~5mAh / cm 2 In some embodiments, the current is in the range of 0.1 mAh / cm 2 ~2mAh / cm 2 In some embodiments, the current is in the range of 0.1 mAh / cm 2 ~1mAh / cm 2 In some embodiments, the current is in the range of 0.1 mAh / cm 2 ~0.5mAh / cm 2 is in the range.

[0023] In some embodiments, the current is 0.5 mAh / cm2 ~2mAh / cm 2 In some embodiments, the current is in the range of 1 mAh / cm 2 ~10mAh / cm 2 In some embodiments, the current is in the range of 2 mAh / cm 2 ~5mAh / cm 2 In some embodiments, the current is in the range of 2 mAh / cm 2 ~10mAh / cm 2 In some embodiments, the current is in the range of 10 mAh / cm 2 ~15mAh / cm 2 In some embodiments, the current is in the range of 0.5 mAh / cm 2 ~1mAh / cm 2 In some embodiments, the current is in the range of 5 mAh / cm 2 ~10mAh / cm 2 is in the range. In some embodiments, the method includes forming a coated lithium plate on a metal current collector. In some embodiments, the coating of the coated lithium plate includes at least nitrogen and fluorine. In some embodiments, the lithium plated on the metal current collector results in improved charge / discharge efficiency in the battery and longer cycle life before failure of the battery cell. [Example]

[0024] Example 1: Preparation of Electrodes / Assembly of Coin Cells Lithium cobalt(III) oxide (LCO) electrodes were prepared using 80% by weight LiCoO2, 8% by weight carbon, and 12% by weight polymer binder. The electrode disks were dried overnight at 120°C under vacuum. Coin cells were prepared under argon with less than 0.1 ppm oxygen and moisture. A double-layer Whatman glass fiber separator was wetted with 150 μl of electrolyte dispensed using a 0-100 μl Thermofisher Finnpipette. The electrolyte composition was prepared under argon and mixed overnight at 850 RPM. The anodeless coin cell plating area was measured using a 5 mil Kapton ring on a scratch coin cell substrate to measure 0.6 cm2. 2 The lithium metal cells were limited to 1.27 cm in size on the coin cell substrate. 2 , 300μm lithium disc and 10mil, 1.19cm 2 A scratched stainless steel (SS316) disc was prepared in the same manner. Electrochemical tests were performed using a Biologic Galvanometer / Potentiostat. Anode-less coin cell experiments were performed at 0.3 mA / cm 2 , 4.2 V, and then constant voltage 0.15 mA / cm 2 and an area current applied of 0.2 mA / cm 2 The lithium plating experiments were carried out using a discharge area current of 0.08 mA / cm to 2.75 V. The cycling capacity was used to evaluate the coulombic efficiency and discharge capacity retention of the tested electrolyte compositions. 2 Charge-discharge tests were performed at 0.5 V or 1 hour using an areal current of 0.5 V. Coulombic efficiency data were analyzed for the electrolyte compositions tested to assess SEI formation. Both experiments were performed after a 1 hour rest period at open circuit voltage. In some embodiments, low-area capacitance plating (LCP) technology allows for direct and amplified observation of the SEI through Coulombic efficiency measurements. Here, LCP is applied to a lithium metal cell configuration, depositing lithium onto a stainless steel substrate. FIG. 2 illustrates a Li metal cell 100 according to an embodiment of the present disclosure. Specifically, the illustrated Li metal cell 100 includes a stainless steel spacer 102, Li metal 104, a glass fiber separator 106, and a stainless steel substrate 108. In some embodiments, as shown in FIG. 2, Li metal 104 is deposited onto the stainless steel substrate 108. In some embodiments, the glass fiber separator 106 separates the stainless steel substrate 108 and Li metal 104. This technique can be used to assess specific contributions to the SEI.

[0025] Example 2: Evaluation of common salts and novel additives Common commercially available electrolyte compositions, such as LiPF salt dissolved in cyclic and linear carbonates, e.g., EC / DMC / EMC, can be limiting for Li battery applications due to their poor thermal and chemical stability, especially when utilized in next-generation Li metal cells. Using ultra-low plating capacity, the electrolyte in Li metal half cells was modified to optimize it and investigate its effect on the formed SEI.

[0026] The initial electrolyte composition used was 1M LiPFEC / DMC. Maintaining the lithium concentration and solvent composition, LiPF was used in place of LiTFSI due to its known beneficial contributions of LiF, morphology benefits to the SEI, and favorable charge transfer kinetics. Table 1 shows the results for the 0.08 mAh / cm Li-metal half-cell. 2Table 1 shows the coulombic efficiency (CE) measurements of the standard reference and reference electrolyte compositions evaluated in Example 1. Salt concentrations and solvent volume ratios are given. Coulombic efficiencies for cycles 1, 10, 20, 50, 100, and 200 are shown. As shown in Table 1, LiPF6 produced a poor first cycle efficiency of 47.3% (versus 58.8% for 1M LiPF6EC / DMC). However, with the addition of FEC, the first cycle efficiency improved to 81.11%, exceeding that of the commercial reference composition (1M LiPF6EC / DMC).

[0027] [Table 1] Additionally, alkali metal additives (CsPF6 and KPF6) were included to establish performance benchmarks. CsPF6 and KPF6 were added to a standard electrolyte of 1M LiPF6EC / DMC at 0.05M and 0.15M, respectively, and tested for coulombic efficiency. Table 2 shows the results for the Li metal half-cell at 0.08 mAh / cm. 2 Figure 1 shows the measured coulombic efficiency of the electrolyte composition of the novel additive evaluated at cycle 1. Coulombic efficiencies are shown for cycles 1, 10, 20, 50, 100, and 200. All solvent components of the electrolyte composition listed are given in terms of volume ratios except for molar ratios indicated by *.

[0028] [Table 2] As shown in Table 2, the first cycle loss and subsequent cycling stability did not improve due to the small volume utilized here to amplify the contribution of the SEI. Additional novel electrolyte formulations were also investigated, including those reported to enable favorable lithium deposition morphology at higher plating capacities. Specifically, the ether-based composition 1.2 M LiTFSI BTFE / TEP (1 / 2 molar ratio) did not show any improvement in first cycle efficiency compared to the compositions shown in Tables 1 and 2.

[0029] Example 3: Incorporation of a novel OS3 solvent In addition to the addition of the FEC additive, a solvent change was made to incorporate additional fluorine components in order to enhance the formation of LiF on the lithium metal interface. A fluoroorganosilyl-based solvent (OS3) was utilized in place of DEC for this purpose. Using 1M LiTFSI salt, which was shown to be beneficial in the 90 / 10EC-DMC / FEC system in Table 1, OS3 was substituted for EC / DM. Table 3 shows the results of the 0.08 mAh / cm2 LiF half-cell analysis. 2 1 shows coulombic efficiency measurements of electrolyte compositions optimized for favorable SEI formation evaluated at 1000 cycles. Coulombic efficiencies for cycles 1, 10, 20, 50, 100, and 200 are shown.

[0030] [Table 3]

[0031] As shown in Table 3, the use of OS3 significantly improves standard electrolyte performance, resulting in modest benefits in first cycle loss and later cycle efficiency. To further explore the benefits of OS3 solvent substitution, the highly charge-transferable salts LiB4 and LiPF6 were used in place of LiTFSI. Both substitutions showed improvements over the standard electrolyte, but neither approached the performance of the 1M LiTFSI composition. Further improvements to the 1M LiTFSI 90 / 10 OS3 / FEC composition were also attempted by substituting 3-methoxypropionitrile (3-MPN) for OS3 and using a higher LiTFSI salt content. Substituting 3-MPN for OS3 did not improve first cycle loss but slightly improved efficiency in later cycles, as shown in Table 3. As shown in Table 3, no significant impact on first cycle loss or cycling stability was observed using a higher LiTFSI salt concentration (2M LiTFSI vs. 1M LiTFSI). The impact of higher molar lithium salt concentrations has been investigated on cycling efficiency at higher capacities, but its contribution to SEI formation in such an amplified LCP experiment set up has not been investigated.

[0032] Example 4: OS3 / FEC-based electrolyte incorporating LDFOB Compositions using LiBF4 and LDFOB salts in a 2 / 1 DEC / FEC were investigated using very low plating capacities. Table 4 shows the results for the 0.08 mAh / cm2 Li metal half cell. 2 1 shows measurements of the coulombic efficiency of electrolyte compositions incorporating OS3 / FEC solvent and LDFOB salt evaluated in Example 1. The coulombic efficiency for cycles 1, 10, 20, 50, 100, and 200 is shown.

[0033] [Table 4]

[0034] As shown in Table 4, direct solvent substitution of DEC and FEC with the OS3 and FEC system in a 0.6M LiBF4 / 0.6M LDFOB 2 / 1 DEC / FEC composition resulted in a higher first cycle efficiency, improving from 67.06% to 82.09%. This composition was further improved by substituting LiBF4 for LiTFSI, decreasing the LDFOB concentration, and increasing the relative content of OS3 (0.6M LiTFSI / 0.4M LDFOB 90 / 10 OS3 / FEC), as shown in Table 4. Further increasing the LiTFSI concentration to 1M slightly reduced first cycle loss while maintaining cycling stability, as shown in Table 4. Substituting LiTFSI for LiFSI in the composition did not result in a significant change in performance, with only a slight decrease in first cycle loss and subsequent cycling efficiency. Therefore, beneficial interactions between the LiTFSI / LDFOB salt system in the OS3 / FEC solvent were identified.

[0035] Example 5: Effect of OS3 to FEC ratio in LiTFSI / LDFOB salt system In the LiTFSI / LDFOB OS3 / FEC system established in the previous range, the ratio of the OS3 and FEC solvent components was varied to understand their interaction. While alone, FEC is not stable with Li metal, it plays an important possible role in stabilizing the solvent against continued undesired decomposition. While decomposition of the fluoroorganosilyl compound allows for the incorporation of Si and F into the SEI, continued decomposition would be detrimental to plating efficiency. Table 5 shows the results for a 0.08 mAh / cm Li metal half-cell. 2 1 shows coulombic efficiency measurements of electrolyte compositions incorporating OS3 / FEC solvent in a LiTFSI / LDFOB salt system evaluated in 1999. Coulombic efficiencies for cycles 1, 10, 20, 50, 100, and 200 are shown.

[0036] [Table 5] As shown in Table 5, for the LiTFSI / LDFOB salt system, increasing the FEC content from 50 / 50 to 90 / 10 slightly improves first cycle efficiency. Here, the effect of FEC is robust over a wide range. As previously shown, the benefit of OS3 / FEC for the 1M LiTFSI system (included again in this table for comparison) clearly indicates that LDFOB and FEC enable the performance of the OS3 / FEC solvent composition.

[0037] Example 6: Transition to Dendritic Crystal Capacity Decay Observation: Optimization of Cell Configuration Area capacity increased from 0.1 to 1 and finally to 3 mAh / cm 2 Increasing the areal capacity of a Li-ion battery to 1000 volts (consistent with the areal capacity of commercially available lithium-ion batteries) results in a systematic increase in first-cycle plating efficiency. Table 6 shows coulombic efficiency measurements for Li metal cell configurations featuring stainless steel and copper substrates evaluated at the indicated areal capacities, utilizing an electrolyte composition of 0.6M LiTFSI 0.4M LDFOB 90 / 10 OS3 / FEC. Coulombic efficiencies for cycles 1, 10, 20, 50, 100, and 200 are shown.

[0038] [Table 6]

[0039] Specifically, the area capacity is 0.1 mAh / cm 2 90% to 1mAh / cm 2 96% and 3mAh / cm 2 The capacity loss increased to 98% at 1000 kJ / s. This trend illustrates the usefulness of low-area capacitance plating studies as a useful tool for separating the initial formation of the SEI from the later-stage lithium deposition. The later-stage lithium deposition interacts chemically differently with the electrolyte and, therefore, may obscure any initial SEI-contributing interactions that may have occurred. Furthermore, the later-stage lithium deposition is characterized by a different morphology than that occurring during the earlier deposition. Applying the LCP technique allowed us to separate the capacity loss associated with these phenomena. As shown, low plating capacity, e.g., 0.08 mAh / cm 2 The use of allows for the evaluation of the SEI formed, and at higher volumes the effect of SEI formation is not evident. In the next section, we transfer these Li metal current collector structures to a LiCoO current collector anodeless design to evaluate the dendrite capacity fade of optimized electrolyte compositions at higher plating capacities.

[0040] Example 7: Observation of Dendritic Crystal Capacity Decay in Anode-less Cells Based on the SEI efficiency study in the Li metal cell setup, promising electrolytes were further investigated in an anode-less cell configuration, using a lithium cobalt oxide (LiCoO) cathode, with lithium plating occurring directly on the stainless steel coin cell substrate. Figure 3 shows an anode-less coin cell 110 with the structure used in the higher capacity plating analysis of dendritic capacity fade. As shown in Figure 3, the anode-less coin cell 110 includes a stainless steel spacer 112, an LCO 114, a glass fiber separator 116, and a Kapton ring 118. Lithium is deposited directly on the stainless steel coin cell substrate, confined to the inner diameter of the thin Kapton ring. The glass fiber is used as a separator between the stainless steel substrate and the LCO cathode. Here, a larger capacity application (e.g., 4 mAh / cm) is required to achieve a higher capacity. 2 ), a wider voltage range (the narrower drop range of 0.08 mAh / cm applied in the Li metal experiment) 2 In addition to the full spectrum of electrolyte products formed through the ion exchange reaction (compared to 4 mAh / cm), we observed a capacity fade over time. 2 capacity of approximately 3 mAh / cm2, which is used in lithium-ion batteries today. 2 It was selected as the applicable area capacity because it exceeds

[0041] To investigate the stability of the OS3 / FEC solvent system in anodeless configurations with high areal capacity, the solvent system was compared to EC / DMC with 1M LiTFSI salt. Table 7 shows the first cycle irreversible loss of electrolyte composition. Figure 4 shows the first cycle irreversible loss of electrolyte composition at 4 mAh / cm. 2 Table 7 shows the discharge capacity retention from cycle 1 using the standard electrolyte composition 1M LiPF6EC / DMC and the optimized solvent replacement composition in an anode-less cell at 25°C. As shown in Table 7, the new solvent replacement resulted in significantly improved first cycle efficiency (irreversible losses of 4.49% and 39.69% for 1M LiTFSI 90 / 10 OS3 / FEC and 1M LiTFSI EC / DMC, respectively).

[0042] [Table 7] As shown in Figure 4, an improvement was also observed at 20 cycles, with the OS3 / FEC substituted composition maintaining greater than 50% discharge capacity (versus approximately 30% discharge capacity retention for the EC / DMC substituted composition). This effect on discharge capacity was also observed, albeit to a lesser extent, using 1M LiPF6 salt with the same solvent substitution. Here, the OS3 / FEC substituted composition improves in terms of irreversible loss compared to the EC / DMC composition, but exhibits similar performance at later cycles.

[0043] Example 8: Effect of common lithium salts in OS3 / FEC solvent systems Because the OS3 / FEC solvent system produced low first cycle losses and stable capacity retention to 20 cycles using LiTFSI as shown in the previous section, the properties of the solvent were further investigated using other commonly utilized lithium salts. LiTFSI was used in place of LiBF4, LiPF6, and LiFSI and compared to compositions previously optimized using SEI observation experiments (0.6M LiTFSI 0.4M LDFOB 90 / 10). Table 8 shows the first cycle irreversible losses of the electrolyte compositions. Figure 5 shows the first cycle irreversible losses of the electrolyte compositions at 4 mAh / cm. 2 1 shows the discharge capacity retention from cycle 1 using lithium salt substitution in the optimized OS3 / FEC solvent in an anode-less cell at 770°C.

[0044] [Table 8] LDFOB is shown to be highly beneficial in combination with LiFSI or LiTFSI salts, as shown in Table 8 and Figure 5. Furthermore, LiBF4 was found to be detrimental in this system, with the lowest initial cycle losses and greater degradation with cycle number.

[0045] Example 9: Effect of OS3 / FEC Solvent Ratio in LiTFSI and LDFOB Salt Systems As mentioned in the previous section, FEC allows for stabilization of the fluoroorganosilyl group. The OS3 / FEC solvent system was optimized using the salt system 0.6M LiTFSI 0.4M LDFOB. OS3 is a strong solvent, and FEC is shown to be an effective factor in improving capacity retention and reducing first cycle loss through stabilization of the SEI film and subsequent decomposition of the OS3 solvent. Table 9 shows the first cycle irreversible loss of the electrolyte compositions. Figure 6 shows the first cycle irreversible loss of the electrolyte composition at 4 mAh / cm. 2 This figure shows the discharge capacity retention from cycle 1 using the lithium salt system 0.6M LiTFSI 0.4M LDFOB with various OS3 / FEC solvent ratios in an anode-less cell at 77°C. As can be seen from Table 9 and Figure 6, omitting FEC from the solvent results in immediate and continuous decomposition of the electrolyte and poor performance, but only 2% is highly effective in stabilizing the system, resulting in irreversible losses <3% and high cycling efficiency. From this optimization range, excess FEC was found to be detrimental, with 8-10% being most beneficial.

[0046] [Table 9]

[0047] Example 10: Effect of LiTFSI and LDFOB salt ratio in optimized OS3 / FEC solvent system The interaction between LDFOB concentration and the optimized solvent 90 / 10 OS3 / FEC was isolated to investigate the interaction between LDFOB and LiTFSI. Table 10 shows the irreversible loss of the first cycle for the electrolyte compositions. Figure 7 shows the irreversible loss of the 4 mAh / cm 2This figure shows the discharge capacity retention from cycle 1 using LiTFSI and LDFOB salt substitution in the optimized OS3 / FEC solvent in an anode-less cell at 77°C. As shown in Table 10 and Figure 7, when varying the LDFOB and LDFOB concentrations as shown, the first cycle irreversible loss differs by less than 1% between compositions. While concentrations above 0.4M LDFOB slightly reduce the benefit against first cycle loss, when paired with LiTFSI, concentrations above 0.2M are required to achieve high efficiency at cycle 20. When comparing the single salt 1M LiTFSI composition with and without LDFOB as shown in Table 6, it is clear that a critical amount of LDFOB is required for the high discharge capacity retention achieved in the OS3 / FEC solvent system.

[0048] [Table 10]

[0049] Example 11: Effect of LiFSI and LDFOB salt ratio in optimized OS3 / FEC solvent system Thus, the LiFSI salt is beneficial in the 90 / 10 OS3 / FEC triple salt system. The interaction between LiFSI and LDFOB in this system was further investigated by varying the LiFSI concentration. Table 11 shows the first cycle irreversible loss of electrolyte composition. Figure 8 shows the first cycle irreversible loss of 4 mAh / cm 2 Figure 8 shows the discharge capacity retention from cycle 1 using LiFSI salt substitution in the optimized OS3 / FEC solvent in an anode-less cell at 77°C. As shown in Table 11 and Figure 8, LiFSI was shown to be achievable as a substitution for LiTFSI in the optimized 0.6M LiTFSI 0.4M LDFOB 90 / 10 OS3 / FEC composition, but concentrations greater than 1M are detrimental in this system.

[0050] [Table 11]

[0051] Example 12: 2.5 mAh / cm2 and 6.5mAh / cm 2 (Capacity fade of reference and optimized compositions at Lower plating capacity (2.5mAh / cm 2 ), irreversible losses are generally expected to be higher, and a similar trend was found to exist for the optimized salt and solvent system, as well as the more common reference composition (1 M LiPF 6 EC / DMC) and literature (0.6 M LiBF 4 0.6 M LDFOB 2 / 1 DEC / FEC), as shown in Table 12 and Figure 9. A very high plating capacity was also observed for the optimized electrolyte composition (6.5 mAh / cm 2), as shown in Table 13 and Figure 10. 2 At lower plating capacities, the LiTFSI / LDFOB and OS3 / FEC relationships identified in the previous section were found to be robust, with optimized electrolyte compositions (0.6M LiTFSI 0.4M LDFOB 90 / 10 OS3 / FEC and 1M LiTFSI 0.4M LDFOB 90 / 10 OS3 / FEC) achieving 4 mAh / cm 2 The plating experiments show a similar trend. Higher plating capacity (6.5 mAh / cm 2 ), the first cycle loss is only slightly improved, demonstrating the robustness of the first cycle efficiency for these optimized compositions.

[0052] [Table 12]

[0053] Further embodiments of the present disclosure can be found in attached Appendix A, which is incorporated herein by reference. The foregoing examples are, of course, intended to be illustrative and not limiting. While several embodiments of the present disclosure have been described, it will be understood that these embodiments are illustrative and not limiting, and that many variations may be apparent to those skilled in the art. Furthermore, the various steps may be performed in any desired order (any desired step may be added and / or any desired step may be removed).

Claims

1. a positive electrode current collector; A positive electrode and an electrolyte comprising a solvent, the solvent comprising at least one of a fluorinated organosilicon and lithium metal; A metal current collector, the metal current collector comprising lithium, the lithium being plated on the metal current collector, and a layer being coated on the lithium-plated metal current collector, the layer comprising at least nitrogen and fluorine. Including batteries.

2. 10. The battery of claim 1, wherein the battery is a lithium metal battery.

3. 10. The battery of claim 1, wherein the battery is a metal battery containing at least one of Si, Ge, Al, Ga, Bi, Ag, Sn, or Au.

4. 2. The battery of claim 1, wherein the fluorinated organosilicon is fluoroethylene.

5. 10. The battery of claim 1, wherein the layer is less than 1000 nm thick.

6. 10. The battery of claim 1, wherein the layer is less than 500 nm thick.

7. The battery of claim 1 , wherein the layer comprises silicon.

8. 2. The battery of claim 1, wherein the ratio of fluorine to organosilicon in the fluorinated organosilicon is from 2:1 to 30:

1.

9. 10. The battery of claim 1, wherein the solvent has a concentration greater than 20% by volume of the electrolyte.

10. a positive electrode current collector; A positive electrode and an electrolyte comprising a solvent, the solvent comprising at least one of a fluorinated organosilicon or lithium metal; a metal current collector, the metal current collector consisting essentially of a non-lithium metal; Including batteries.

11. 11. The battery of claim 10, wherein the battery is a lithium metal battery.

12. 11. The battery of claim 10, wherein the battery is a metal battery containing at least one of Si, Ge, Al, Ga, Bi, Ag, Sn, or Au.

13. 11. The battery of claim 10, wherein the fluorinated organosilicon is fluoroethylene.

14. 11. The battery of claim 10, wherein the ratio of fluorine to organosilicon in the fluorinated organosilicon is from 2:1 to 30:

1.

15. 11. The battery of claim 10, wherein the solvent has a concentration greater than 20% by volume of the electrolyte.

16. 1. A method of forming a lithium battery, comprising: obtaining a battery, the battery comprising: a positive electrode current collector; a positive electrode; an electrolyte, the electrolyte comprising a solvent, the solvent comprising at least one of a fluorinated organosilicon or a lithium metal; and a metal current collector, the metal current collector consisting essentially of a non-lithium metal; The metal current collector has a current capacity of 0.1 to 20 mAh / cm 2 applying a current in the range of forming a coated lithium plating on the metal current collector, the coated lithium plating including a coating layer containing at least nitrogen and fluorine; A method comprising:

17. 17. The battery of claim 16, wherein the fluorinated organosilicon is fluoroethylene.

18. 17. The battery of claim 16, wherein the layer is less than 1000 nm thick.

19. 17. The battery of claim 16, wherein the layer is less than 500 nm thick.

20. 17. The battery of claim 16, wherein the layer comprises silicon.

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