Functional interface stabilizers for battery electrodes

Abstract

The present disclosure relates to a functional interface stabilizer for a battery having an organic non-aqueous solvent and a lithium salt soluble with the organic non-aqueous solvent. The present disclosure also relates to a battery having an anode, a cathode, a separator, a functional interfacial stabilizer having an organic non-aqueous solvent, and a lithium salt soluble with the organic non-aqueous solvent. The present disclosure also relates to a method of preparing a functional interface stabilizer comprising the steps of providing an organic non-aqueous solvent, adding a lithium salt to the organic non-aqueous solvent, and mixing the organic non-aqueous solvent with the lithium salt to form a solution.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 380,889, filed on October 25, 2022, the entire contents of which are incorporated herein by reference.

[0003] Government assistance

[0004] Pursuant to 35 U.S.C. §202(c)(6), applicants hereby declare that the invention disclosed in this specification was made with support from the U.S. federal government (Department of Defense, Contract No. N6893622C00180) and that the U.S. federal government has certain rights in this invention. Technical Field

[0005] The present invention teaches the use of liquid functional interfacial stabilizers that mediate the formation of stable solid electrolyte and cathode electrolyte interfaces in lithium rechargeable batteries and can be used in liquid electrolytes in lithium rechargeable cells or together with solid electrolytes. Background Art

[0006] The electrification of mobility sectors such as the automotive and aviation industries requires energy storage devices with high gravimetric and volumetric energy density, reasonable charging speed capabilities, high charge / discharge cycle life, low cost, and high thermal and mechanical abuse stability.

[0007] Although lithium-ion batteries (LIBs) have found widespread use in consumer electronics and electric vehicles, they still face safety and performance-related shortcomings. These limitations can be traced back to the organic liquid electrolytes (LEs) that LIBs rely on.

[0008] Mainstream LIB designs typically use LE-impregnated separators made of polyethylene (PE), polypropylene (PP), or PE / PP composite blends. LE is often lithium hexafluorophosphate (LiPF 6 ) in about 1 molar solution in a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC) and other organic solvents. These solvents decompose at different electrochemical potentials on the electrode surface to form different free radicals or ions, which then react continuously to produce several compounds. Due to the high surface energy of the electrode site, these compounds gradually develop into a mixed layer of organic and inorganic materials deposited on the electrode site, resulting in the development of a solid electrolyte interface (SEI) film and a cathode electrolyte interface (CEI) film at the interface of anode material / cathode material and separator. Both SEI film and CEI film play an important role in cycle stability, coulombic efficiency, rate performance and safety.

[0009] Lithium metal batteries (LMBs), which use metallic lithium as their anode rather than graphite carbon like LIBs, have the potential to offer greatly improved energy density performance characteristics. Unfortunately, the Li metal anode (LMA) exacerbates the negative effects of SEI generation. Although LMAs have a capacity of over 3000 mAh g -1 The theoretical specific capacity (compared to 370 mAh g -1 The theoretical specific capacity of the LMB cell is 200 MW (compared to a conventional graphite anode with a theoretical specific capacity of 200 MW), but the surface of the LMA is highly reduced and quickly decomposes the LE into SEI products. With each charge / discharge cycle of the LMB cell, the LMA consumes more LE and converts it into SEI. This continued growth leads to an unfavorable thick SEI layer, which increases the internal impedance of the LMB cell and reduces the cycle life due to increased polarization. The continuous growth of additional SEI also removes cyclable lithium from the cell system and converts it into irreversible SEI products. This phenomenon also reduces the cell capacity with each cycle.

[0010] In addition, the SEI layer may be mechanically unstable and crack, which can lead to exposure of bare lithium metal surfaces without protection from the SEI film. Lithium dendrites can form on these exposed interfaces. Dendrite growth can pierce the separator of the battery cell and cause internal short circuits. The rapid temperature rise accompanying this failure mode can trigger battery fire / explosion due to vaporization of LE. A stable SEI layer is critical to prevent the formation of these unfavorable lithium dendrites and improve the long-term cycling stability of the battery.

[0011] Considering the important role of SEI in the performance of LMBs, the battery industry has recently increased its efforts to improve the SEI kinetics of LMAs. The new approach involves the use of solid-state electrolytes (SSEs) that are more thermally and electrochemically stable than LEs. The enhanced elasticity of properly designed SSEs slows down the runaway SEI growth because they cannot be reduced by LMAs. They are also not easily converted into flammable gaseous products.

[0012] SSEs are usually composed of ceramic, polymer or composite materials. Although ceramic materials offer similar ionic conductivity to LE, their synthesis, processing and large-scale application in LIBs and mass-produced LMBs face challenges. On the other hand, SSEs made of polymer materials have excellent mechanical properties and can be more easily integrated into existing battery production equipment, but they often have limitations in achieving fast ion transport at room temperature.

[0013] Furthermore, ceramic-based SSEs, despite exhibiting high bulk ion transport properties, have high resistivity at their interfaces with electrodes. A common strategy to circumvent interfacial resistance is to use stack pressure. Uniaxial compression of cell stacks has been repeatedly shown to not only reduce internal cell resistance but also facilitate efficient Li deposition / stripping on LMAs, characterized by high Coulombic efficiency with cyclable lithium retention and low polarization growth. However, excessive external uniaxial compression (>5 atm) always requires placing the cells in a mechanical clamping device. This device adds mass and volume, weakening the energy density gain of LMBs.

[0014] In summary, it is necessary to develop solutions that promote the formation of a stable SEI to address and overcome the above-mentioned problems in the prior art. Summary of the invention

[0015] The following is a summary to provide an initial understanding of the teachings herein. This summary does not necessarily identify key elements, nor does it limit the scope of the teachings, but merely serves as an introduction to the following description.

[0016] One aspect of the present teachings provides a LIB or LMB having a dense active solid electrolyte separator or a porous inactive separator and a functional interphase stabilizer (FIS).

[0017] The present teaching provides a LIB or LMB having a porous separator or a dense SSE separator and a FIS. The FIS stabilizes the interface between the anode electrode and the separator by forming a SEI during the formation cycle of the battery cell. The SEI formed by the FIS is durable and uses minimal recyclable lithium. This improves the coulombic efficiency of the battery cell in subsequent cycles and helps to improve cycle stability and cycle life. In the present method, most of the FIS is reduced to a solid SEI product, while a limited residual liquid FIS is left. This means that after the formation cycle, the liquid volume inside the battery cell using the FIS is reduced and the volatile phase is minimized.

[0018] FIS forms a stable SEI on the anode surface, which mechanically adheres to the porous PE / PP or dense SSE separator. This prevents the SEI from breaking due to the volume dynamics of the anode active material during lithiation / delithiation. This dynamic is particularly problematic for LMA or silicon-based anodes, which may exhibit a volume expansion of 300% during charge and discharge, and silicon-based anodes expand up to 400%. Therefore, the thin, flexible SEI produced by FIS also supports improved cycle life. Simultaneous adhesion to the anode and separator also supports low resistivity of the electrolyte / SEI and SEI / anode interfaces. This low resistivity is maintained even at low stack pressures (e.g., external uniaxial compression of a cell stack of 0 to 3.4 atm) and with a solid electrolyte separator.

[0019] The addition of FIS at the interface between the cathode electrode and the separator also improves the current density performance of the battery. FIS reduces the interfacial resistance between the cathode and the electrolyte, which allows higher charge and discharge current densities (e.g., ≥4 mA cm) with lower polarization. -2 ). For example, CEI obtained by decomposition of FIS on the cathode can protect the separator from the high oxidative activity of high-performance cathode materials with high specific surface area and nickel content. CEI can also prevent the dissolution of transition metals (such as manganese) from manganese-containing spinel and transition metal oxide cathode materials. The dissolution of manganese ions from these active materials and the migration to the anode (where they participate in parasitic side reactions) is called "electrode crosstalk" and is another mechanism that may adversely affect the cycling stability of advanced lithium secondary batteries.

[0020] In one aspect, the present teachings provide a battery including an anode including an active material based on graphitic carbon, a metalloid (such as silicon, silicon oxide, or a silicon-carbon composite), lithium metal, or a composite containing two or more of these materials.

[0021] In one aspect, the present teachings provide a battery including a cathode including an active material based on spinel, olivine, or a transition metal oxide.

[0022] In one aspect, the present teachings provide a battery including a separator made of a porous polyolefin such as polyethylene, polypropylene, or a composite thereof, or a dense solid electrolyte including a ceramic or a polymer or a composite thereof.

[0023] In one aspect, the present teachings provide a battery comprising a FIS comprising at least one organic solvent and at least one dissolved lithium salt.

[0024] In one aspect, the present teachings provide batteries in which the FIS can be wetted onto the separator or electrode before or during the battery assembly process, or it can be injected into the battery after the battery assembly. The FIS can be used for batteries of any size or shape including button cells and pouch cells.

[0025] In one aspect of the present disclosure, provided is a FIS for a battery having an organic non-aqueous solvent and a lithium salt miscible with the organic non-aqueous solvent.

[0026] In another aspect of the present disclosure, the lithium salt has a solution concentration of about 0.1M to about 8M.

[0027] In another aspect of the present disclosure, the organic non-aqueous solvent includes 1,2-dimethoxyethane (DME), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), dimethyl sulfide (DMS), fluoroethylene carbonate (FEC), dimethyl sulfoxide (DMSO), dimethyl methylphosphonate (DMMPh), trimethyl phosphate (TMP), tris(trimethylsilyl)phosphite (TMSPi), dioxolane (DOL), 1,1-diethoxyethane (DE E), tetrahydrofuran (THF), triphenyl phosphate (TPhP), tri(2,2,2-trifluoroethyl) orthoformate (TFEO), vinylene carbonate (VC), triethyl phosphate (TEP), sulfolane (SL), methyl 1,1,2,2-tetrafluoroethyl ether (TFME), methyl β-L-fucopyranoside (MFB), 1,2-(1,1,2,2-tetrafluoroethoxy)ethane, 1,1,2,2-tetrafluoroethyl-1H,1H,5H-octafluoropentyl ether or acetonitrile.

[0028] In another aspect of the present disclosure, the lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluoromethanesulfonyl)imide (LiFSI), lithium fluoride (LiF), lithium nitrate (LiNO3), lithium difluoro(oxalato)borate (LiDFOB), lithium iodide (LiI), lithium difluorophosphate (LiPO2F2) or lithium hexafluorophosphate (LiPF6).

[0029] In another aspect of the present disclosure, a battery is provided, the battery having an anode, a cathode, a separator, a functional interface stabilizer having an organic non-aqueous solvent, and a lithium salt miscible with the organic non-aqueous solvent;

[0030] In another aspect of the present disclosure, the lithium salt has a solution concentration of about 0.1M to about 8M.

[0031] In another aspect of the present disclosure, the non-aqueous solvent includes 1,2-dimethoxyethane (DME), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), dimethyl sulfide (DMS), fluoroethylene carbonate (FEC), dimethyl sulfoxide (DMSO), dimethyl methylphosphonate (DMMPh), trimethyl phosphate (TMP), tris(trimethylsilyl)phosphite (TMSPi), dioxolane (DOL), 1,1-diethoxyethane (DEE) , tetrahydrofuran (THF), triphenyl phosphate (TPhP), tri(2,2,2-trifluoroethyl) orthoformate (TFEO), vinylene carbonate (VC), triethyl phosphate (TEP), sulfolane (SL), methyl 1,1,2,2-tetrafluoroethyl ether (TFME), or methyl β-L-fucopyranoside (MFB), 1,2-(1,1,2,2-tetrafluoroethoxy)ethane, 1,1,2,2-tetrafluoroethyl-1H,1H,5H-octafluoropentyl ether or acetonitrile.

[0032] In another aspect of the present disclosure, the lithium salt includes lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluoromethanesulfonyl)imide (LiFSI), lithium fluoride (LiF), lithium nitrate (LiNO 3 ), lithium difluoro(oxalate)borate (LiDFOB), lithium iodide (LiI), lithium difluorophosphate (LiPO 2 F 2 ) or lithium hexafluorophosphate (LiPF 6 ) at least one of.

[0033] In another aspect of the disclosure, the battery further includes a solid electrolyte interface on the surface of the anode.

[0034] In another aspect of the disclosure, the solid electrolyte interface on the anode surface is mechanically adhered to the separator.

[0035] In another aspect of the disclosure, the battery further includes a cathode electrolyte interface on the cathode surface.

[0036] In another aspect of the disclosure, the cathode electrolyte interface on the cathode surface is mechanically adhered to the separator.

[0037] In another aspect of the present disclosure, the separator is selected from the group consisting of polyethylene, polypropylene, polyolefin, microporous membrane, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, woven fabric, glass fiber woven fabric, polyethylene terephthalate fiber woven fabric, cellulose, aramid fiber, other organic or synthetic fibers, ceramic, composite polymer-ceramic solid electrolyte or a polymer film or multilayer film of a combination thereof. The separator may also be provided with a functional polymer and / or ceramic coating to enhance its thermal and / or mechanical properties.

[0038] In another aspect of the present disclosure, the cathode is selected from the group consisting of: lithium cobalt phosphate (LiCoPO 4 ), lithium iron phosphate (LiFePO 4 ) and lithium metal oxide (LiMeO x ), wherein Me is one or more metals selected from nickel (Ni), cobalt (Co), manganese (Mn), aluminum (Al), Li and O represent one or more corresponding lithium atoms and oxygen atoms, and x represents the number of oxygen atoms. For example, LiNi is usually selected. 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) is used as a favorable cathode active material. The cathode may also be selected from the group consisting of any other suitable spinel, olivine, sulfide, selenide, halide or combination thereof with or without lithium.

[0039] In another aspect of the present disclosure, the anode is selected from the group consisting of carbon-based anode active materials, graphite carbon, carbon fibers, tin oxide compounds, silicon oxides, silicon metal, silicon-carbon composites, lithium metal, lithium alloys, or combinations thereof.

[0040] In another aspect of the present disclosure, a method for preparing a functional interface stabilizer is provided, the method having the steps of providing an organic non-aqueous solvent, adding a lithium salt to the organic non-aqueous solvent, and mixing the organic non-aqueous solvent and the lithium salt to form a solution.

[0041] In another aspect of the present disclosure, the method includes the steps of adding an additive to the solution and mixing the solution until the additive is dissolved or homogenized.

[0042] In another aspect of the disclosure, the additive is an auxiliary salt.

[0043] In another aspect of the disclosure, the method includes the steps of adding a diluent to the solution and mixing the solution until the diluent is homogenized.

[0044] In another aspect of the disclosure, the diluent is a co-solvent.

[0045] These additional and / or other aspects and / or advantages of the present disclosure are set forth in the detailed description which follows; may be inferred from the detailed description; and / or may be learned by practice of the present disclosure.

[0046] Other features and aspects of the present teachings will become apparent from the following detailed description taken in conjunction with the accompanying drawings, which illustrate, by way of example, features of embodiments according to the present teachings.This summary is not intended to limit the scope of the present teachings. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a flow chart illustrating the production of a functional interfacial stabilizer (FIS).

[0048] Figure 2 It is a schematic diagram of the cross section of a button cell.

[0049] Figure 3 This is a picture of a soft-pack battery.

[0050] Figure 4 is an equivalent circuit used to determine the electrochemical impedance of the battery cell, where R L Proportional to the ionic conductivity (itself a function of the ionic conductivity of the FIS, electrolyte, and separator), R ct represents the charge transfer resistance, C dl is the capacitor corresponding to the double layer capacitance, and W is the Warburg element modeling the diffusion impedance.

[0051] Figure 5A and Figure 5B The cathode and the anode of lithium metal were NMC811 and (i) 1.2 M LiPF in 3:7 (w / w) ethylene carbonate (EC) / ethyl methyl carbonate (EMC). 6 Nyquist plots generated from electrochemical impedance spectroscopy of 2-layer 96 mAh soft-pack cells composed of (i) a conventional carbonate electrolyte with a PE / PP separator, and (ii) FIS with a dense polymer-ceramic composite solid electrolyte separator. The soft-pack cells were under external uniaxial stack compression of 2.25 atm and room temperature, and the EIS was measured from 1 MHz to 0.1 Hz after the cells completed the formation cycle. The lower x-intercept of the FIS cell indicates a lower R L (higher ionic conductivity), and the smaller diameter of the semicircular portion of the FIS spectrum compared to the carbonate electrolyte spectrum indicates a lower R ct (charge transfer resistance).

[0052] Fig. 6A and Figure 6BThe 3.58 mAh coin cell made of NMC811 cathode, 250 μm thick LMA and FIS with a dense polymer-ceramic composite solid electrolyte separator was shown to operate at 4 mA cm between 3 V and 4.2 V at room temperature. -2 Discharge capacity retention and cycling Coulombic efficiency for symmetric charge and discharge.

[0053] Fig. 7A , Figure 7B and Figure 7C The results show that the cathode of NMC811, 20 μm thick LMA and 1.2 M LiPF in 3:7 (w / w) ethylene carbonate (EC) / ethyl methyl carbonate (EMC) can be synthesized under external uniaxial compression at room temperature using 0 atm. 6 Charging of 96mAh 2-layer soft pack battery made of PE / PP separator ( Fig. 7A The circle in Figure 7C The slope of the increase) and discharge ( Fig. 7A The square in Figure 7C The slope of the decrease in the charge (normalized for the mass of cathode active material), the cycle coulombic efficiency and the capacity / voltage curves are shown. The charge was included at 0.67 mA cm -2 The battery was charged to 4.25V at constant current and 0.1mA cm at constant voltage at 4.25V. -2 Cut-off, at 0.67 mA cm -2 Discharge at constant current to 2.5V.

[0054] Fig. 8A , Figure 8B and Figure 8C Shown is the charging performance of a 96 mAh 2-layer pouch cell made of NMC811 cathode, 20 μm thick LMA and FIS with PE / PP separator under external uniaxial compression at room temperature using 0 atm ( Fig. 8A The circle in Figure 8C The slope of the increase) and discharge ( Fig. 8A The square in Figure 8C The slope of the decrease in the charge (normalized for the mass of cathode active material), the cycle coulombic efficiency and the capacity / voltage curves are shown. The charge was included at 0.67 mA cm -2 The battery was charged to 4.25V at constant current and 0.1mA cm at constant voltage at 4.25V. -2 Cut-off, at 0.67 mA cm -2 Discharge at constant current to 2.5V.

[0055] Fig.9A , Fig. 9B and Fig. 9CThe charging performance of a 96 mAh 2-layer pouch cell made of NMC811 cathode, 20 μm thick lithium metal anode LMA and FIS with a dense polymer-ceramic composite solid electrolyte separator is shown under external uniaxial compression at room temperature using 0 atm. Fig.9A The circle in Fig. 9C The slope of the increase) and discharge ( Fig.9A The square in Fig. 9C The slope of the decrease in the charge (normalized for the mass of cathode active material), the cycle coulombic efficiency and the capacity / voltage curves are shown. The charge was included at 0.67 mA cm -2 The battery was charged to 4.25V at constant current and 0.1mA cm at constant voltage at 4.25V. -2 Cut-off, at 0.67 mA cm -2 Discharge at constant current to 2.5V.

[0056] Fig. 10A and Fig. 10B The discharge capacity retention and cycling coulombic efficiency of a 48 mAh 1-layer pouch cell made of an NMC811 cathode, 20 μm thick LMA and FIS with a porous PE / PP separator are shown under external uniaxial compression at 3.4 atm at room temperature. -2 The battery was charged to 4.2V at constant current and 0.05mA cm at constant voltage at 4.2V. -2 Cut-off, at 1mA cm -2 Discharge at a constant current to 3V.

[0057] Fig.11A and Fig. 11B The 3.58 mAh button cell made of NMC811 cathode, graphite anode and PE / PP separator was shown to be charged at 1 mA cm at room temperature. -2 Discharge capacity retention and cycle coulombic efficiency for symmetrical charge and discharge. Charging includes -2 The battery was charged to 4.2V at constant current and 0.1mA cm at constant voltage at 4.2V. -2 Cut-off, at 1mA cm -2 Discharge at a constant current to 3V.

[0058] Fig. 12A , Fig. 12B and Fig. 12C It is shown that at room temperature, the SiO x The charging performance of a 7.16 mAh button cell made of an anode with a thickness of 250 μm (x is the number of oxygen atoms) and a PE / PP separator with a thickness of 250 μm LMA and FIS as the counter electrode ( Fig. 12A The circle in Fig. 12C The slope of the decrease) and discharge ( Fig. 12A The square in Fig. 12C The slope of the increase in the specific capacity (normalized for the mass of the anode active material), the cycling Coulombic efficiency and the capacity / voltage curves are shown. The cycling was performed at 2 mA cm -2 The charge and discharge are symmetrical between 0.05V and 1V.

[0059] Fig.13A , Fig. 13B and Fig. 13C The charging performance of a 7.16 mAh coin cell made of a SiC-based anode, 250 μm thick LMA and FIS as counter electrodes and a porous PE / PP separator is shown at room temperature. Fig.13A The circle in Fig. 13C The slope of the decrease) and discharge ( Fig.13A The square in Fig. 13C The slope of the increase in the specific capacity (normalized for the anode active material mass), cycle coulombic efficiency and capacity / voltage curves are shown. The cycles consisted of symmetrical charge and discharge between 0.05 V and 1 V. The 1st to 5th cycles were carried out at 0.8 mA cm -2 The current density was 2 mA cm-1 for the 6th to 10th cycles. -2 The 11th to 15th cycles were completed at 4 mA cm -2 completed, and the 16th to 20th cycles were performed at 0.8 mA cm -2 Finish. DETAILED DESCRIPTION

[0060] The present teaching will be described more fully below with reference to the accompanying drawings, which are a part of this specification and in which embodiments of the invention are shown. The description presented below is for illustrative purposes only, and the present teaching should not be limited to these embodiments.

[0061] In the following description, various aspects of the present disclosure are described. For the purpose of explanation, specific configurations and details are set forth to provide a thorough understanding of the present disclosure. However, it is obvious to those skilled in the art that the present disclosure can be practiced without the specific details presented herein. In addition, well-known features may be omitted or simplified so as not to make the present disclosure unclear. With specific reference to the accompanying drawings, it is emphasized that the details shown by way of example are only for the purpose of illustrative discussion of the present disclosure, and are presented to show the most useful and easy-to-understand description of the principles and concepts considered to be the present disclosure. In this regard, no attempt is made to show the structural details of the present disclosure in more detail than is necessary for basic understanding, and the description in conjunction with the accompanying drawings makes it clear to those skilled in the art how several forms of the present disclosure can be embodied in practice.

[0062] Before explaining the present disclosure in detail, it should be understood that the present disclosure is not limited in its application to the details of the structure and arrangement of the components set forth in the following description or shown in the accompanying drawings. The present disclosure is applicable to other disclosures and combinations thereof, which can be practiced or implemented in various ways. In addition, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered restrictive.

[0063] The present teachings provide efficient and economical methods and mechanisms for improving the cycle life of lithium rechargeable batteries and thereby provide improvements to the field of technology or energy storage.

[0064] The present teachings therefore relate to LIB cells, LMB cells and functional interfacial stabilizers (FIS). The FIS comprises a lithium salt and an organic solvent, and the FIS stabilizes the solid electrolyte interface (SEI) at the surface of the anode material particles and / or the cathode electrolyte interface (CEI) at the surface of the cathode material particles. The surface layer on the anode and / or cathode can be formed by a mechanism including partial decomposition of chemicals present in the electrolyte composition. The lithium salt can be incorporated into the surface layer.

[0065] Figure 1 A method 10 for producing FIS is shown. First, in step 11, a primary lithium salt (e.g., a salt discussed below) is added to a primary solvent (e.g., a solvent discussed below) and mixed to produce a solution. In step 12, optional additives such as secondary salts (including any of the lithium salts discussed below, such as LiDFOB and LiNO) are added to the primary solvent. 3 In step 13, optional diluents such as secondary solvents (including any organic solvents discussed below, such as HFE such as TTE) are added to the solution and mixed until dissolved or homogenized.

[0066] Figure 2 A button cell battery 20 is shown. The button cell battery 20 has a negative electrode casing 21 and a positive electrode casing 28. A spring 22 is located next to the negative electrode casing 21. A separator 25 is sandwiched between an anode (negative electrode) 23 and a cathode (positive electrode) 27. Functional interfacial stabilizers (FIS) 24, 26 are added to the surfaces of the anode 23 and the cathode 27, respectively. The functional interfacial stabilizers 24, 26 may be the same or different. The functional interfacial stabilizers 24, 26 may be added to the anode 23, the cathode 27, or both. Although Figure 2 A button cell battery 20 is shown, but it should be noted that the battery 20 may be used as a Figure 3The invention can be provided in the soft package shown in , or in other forms that will be understood by those skilled in the art.

[0067] Functional interface stabilizers 24, 26 may include a lithium ion migration source. Any lithium salt material commonly used in LE for LIB may be used. The lithium salt may be representatively selected from any one material or a mixture of at least two materials in the following group:

[0068] a. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI),

[0069] b. Lithium bis(fluoromethanesulfonyl)imide (LiFSI),

[0070] c. Lithium fluoride (LiF),

[0071] d. Lithium nitrate (LiNO 3 ),

[0072] e. Lithium difluoro(oxalato)borate (LiDFOB),

[0073] f. Lithium iodide (LiI),

[0074] g. Lithium difluorophosphate (LiPO 2 F 2 ),

[0075] h. Lithium hexafluorophosphate (LiPF 6 ).

[0076] The lithium salt is preferably used in a concentration range of 0.1 M to 8.0 M. If the concentration of the lithium salt is less than 0.1 M, the concentration is low, thereby reducing the performance of the stabilizer. On the other hand, if the concentration of the lithium salt is greater than 8.0 M, the viscosity of the stabilizer increases, thereby reducing the mobility of lithium ions and reducing the performance at low temperatures.

[0077] Functional interface stabilizers 24, 26 may include organic solvents. Any ether-based and carbonate-based materials commonly used in electrolytes for lithium-ion rechargeable batteries may be used. As a representative example, the organic compound may include any one material or a mixture of at least two materials selected from the group consisting of:

[0078] Ethers, including:

[0079] 1,2-dimethoxyethane (DME), and / or

[0080] 1,1-Diethoxyethane (DEE),

[0081] Hydrofluoroethers (HFEs), including:

[0082] 1,1,2,2-tetrafluoroethyl methyl ether (TFME), and / or

[0083] 1,1,2,2-Tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE),

[0084] 1,2-(1,1,2,2-tetrafluoroethoxy)ethane,

[0085] 1,1,2,2-Tetrafluoroethyl-1H,1H,5H-octafluoropentyl ether,

[0086] Fluorinated carbonates, including fluoroethylene carbonate (FEC),

[0087] Organic sulfur, including:

[0088] Dimethyl sulfide (DMS),

[0089] Dimethyl sulfoxide (DMSO), and / or

[0090] Sulfolane (SL),

[0091] Phosphate esters, including:

[0092] Triethyl phosphate (TEP),

[0093] Trimethyl phosphate (TMP),

[0094] dimethyl methylphosphonate (DMMPh), and / or

[0095] Triphenyl phosphate (TPhP),

[0096] Phosphites, including tris(trimethylsilyl)phosphite (TMSPi),

[0097] Cyclic ethers, including tetrahydrofuran (THF),

[0098] Fluorinated orthoesters, including tris(2,2,2-trifluoroethyl)orthoformate (TFEO),

[0099] Carbonates, including vinylene carbonate (VC),

[0100] Nitriles, including acetonitrile,

[0101] Methyl β-L-fucopyranoside (MFB),

[0102] Other heterocyclic organic solvents include dioxolane (DOL).

[0103] Among carbonate-based organic solvents, cyclic carbonates such as EC and PC can be preferably used because they have high viscosity, so that they show high dielectric constants and thus dissociate lithium salts in FIS. In addition, if linear carbonates such as DMC and EDC having low viscosity and low dielectric constants are mixed with cyclic carbonates in a suitable ratio, FIS with high electronic conductivity can be prepared.

[0104] The FIS for LIB or LMB is injected into an electrode structure having an anode 23, a cathode 27, and a porous inactive separator 25 or a dense active SSE separator 25 interposed between the anode 23 and the cathode 27, thereby making a LIB or LMB battery cell. The anode 23, the cathode 27, and the separator 25 may be made of any kind of material commonly used to manufacture lithium-ion rechargeable batteries, such as those discussed below.

[0105] The cathode 27 may be formed of a metal oxide, a layered oxide, a spinel, an olivine, a disordered rock salt or other structures, which may be used to receive Li ions by intercalation / deintercalation. More specifically, the cathode 27 active material may preferably be a lithium-containing transition metal oxide or phosphate, for example, any one material or a mixture of at least two materials selected from the group consisting of:

[0106] LiCoO 2 ,

[0107] LiNiO 2 ,

[0108] LiMnO 2 ,

[0109] LiMn 2 O 4 ,

[0110] LiNi A Mn B Co C O 2 (0 <A<1,0<B<1,0<C<1,A+B+C=1),

[0111] LiNi A Mn B Co C O 2 (0 <A<2,0<B<2,0<C<2,A+B+C=2),

[0112] LiNi 1-Y Co Y O 2 (0≤Y<1),

[0113] LiCo 1-Y MnY O 2 (0≤Y<1),

[0114] LiNi 1-Y Mn Y O 2 (0≤Y<1),

[0115] LiMn 2-Z Ni Z O 4 (0 <Z<2),

[0116] LiMn 2-Z Co Z O 4 (0 <Z<2),

[0117] LiCoPO 4 ,as well as

[0118] LiFePO 4 .

[0119] Furthermore, in addition to the above oxides, sulfides, selenides, and halides may be used as dopants for the cathode active material. The cathode may contain a binder such as polyvinylidene fluoride (PVDF) and a conductive additive such as amorphous carbon or carbon nanotubes.

[0120] Anode 23 active material can be formed by carbon material, lithium metal or silicon-based material, which can be used to store lithium ions by embedding / de-embedding, forming intermetallic phase, direct deposition (deposition / stripping) or a combination of these. Among them, carbon material is a conventional choice. Carbon material can be low crystallinity carbon or high crystallinity carbon. As a representative example, low crystallinity carbon can be soft carbon or hard carbon, and as a representative example, high crystallinity carbon can be natural graphite, Kish graphite, pyrolytic carbon, carbon fiber based on mesophase pitch, mesophase carbon microspheres, mesophase pitch or high temperature sintered carbon, such as coke derived from petroleum or coal tar pitch. Anode 23 can contain a binder, which can use various binder polymers, such as PVDF, PVDF-co-hexafluoropropylene (HFP), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyacrylic acid (PAA) and carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR).

[0121] In addition, separator 25 can be formed by conventional porous polymer film in monolayer or laminated form, such as taking the porous polymer film made of ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer or ethylene / methacrylate copolymer as an example. In other cases, separator 25 can be formed by woven fabric or conventional porous nonwoven fabric (such as nonwoven fabric made of glass fiber or polyethylene terephthalate fiber with high melting point), but it is limited to this. Porous separator 25 can also be made of cellulose, aramid fiber or other organic or synthetic fibers. Separator 25 can also be composite polymer-ceramic solid electrolyte. Separator 25 can also have functional ceramic or polymer coating that enhances its thermal stability, mechanical stability and / or electrochemical stability.

[0122] Example 1 illustrates an exemplary process for synthesizing FIS. Example 2 illustrates an exemplary process for producing FIS.

[0123] Example 1: Synthesis of FIS

[0124] The solution was prepared by using 5 ml of solvent as a base. First, 4.35 g of DME (5 ml) was charged into a vial. The solid additive was dissolved in the DME solvent, and then 0.14 g of LiNO was introduced. 3 , thus forming 0.4M LiNO 3 To produce a 2M LiFSI salt solution, 1.871 g of LiFSI was used as the main salt and was carefully incorporated into the solution and mixed thoroughly. Subsequently, the solution was blended with sulfolane in a volume ratio of 1:1 with DME.

[0125] Example 2: Synthesis of FIS

[0126] All concentration measurements and ratios are estimated based on the mass and volume of undiluted solutions without hydrofluoroether diluent. First, the solid additives were dissolved. The solution was prepared by using 5 ml of solvent as a base. First, 4.35 g of DME (5 ml) was charged to a vial. Subsequently, 0.14 g of LiNO 3 To produce 0.4M LiNO 3 After this step, LiDFOB was added to the solution, where the LiDFOB concentration constituted the previous solution (LiFSI + LiNO 3 +DME). The solution was stirred until complete dissolution of LiDFOB was achieved. In addition, 1.871 g of LiFSI was added to the solution as the main salt and mixed thoroughly to produce a 2M LiFSI salt solution. After this stage, any liquid additives can be introduced. Specifically, 2 wt% (relative to LiFSI+DME+LiNO 3)VC was added to the solution and stirred for a duration of 5 minutes. Subsequently, the solution was diluted to half of its initial concentration using an appropriate volume (in this case, 5 ml or 7.5 g) of TTE in a 1:1 volume ratio with DME.

[0127] After preparing the FIS in Examples 1 and 2, their electrochemical performance and compatibility with electrodes and solid electrolytes or separators were evaluated using electrochemical impedance spectroscopy (EIS). The half-cell and full-cell structures including anode materials, cathode materials, and electrolyte materials with added FIS were characterized by EIS at different stages of battery cell manufacturing, for example, Figure 2 The EIS experiment will produce a measurement frequency of 10 6 Up to 10 -1 Hz Nyquist plot. Figure 4 The equivalent resistance circuit shown in simulates the EIS data from the Nyquist plot to measure the change in impedance of the battery cell. Figure 4 , R L represents the ohmic resistance of the test cell, where the effectiveness and performance of the FIS are observed, R ct represents the charge transfer resistance, C dl represents the electrochemical double layer capacitance, and W represents the Warburg diffusion element simulating the diffusion process. A typical result of the EIS test is shown in FIG5 .

[0128] The constructed full battery cell was then evaluated in constant current cycling and rate performance tests. During the rate performance test, the entire cell was discharged and charged at various current rates. The discharge current was gradually increased from 1 / 5C rate to 2C rate, and the C rate is a measure of the discharge rate of a battery relative to its maximum capacity. The voltage response and specific capacity of the battery are monitored during each cycle to evaluate its performance. On the other hand, constant current cycling involves continuously cycling the lithium battery at a constant current between a defined upper voltage limit and a lower voltage limit. During constant current cycling, the battery cell is cycled at a voltage between 3.0V and 4.2V. This charge and discharge process is repeated multiple times to simulate the typical usage pattern of the battery. The key parameters monitored during constant current cycling include the voltage profile, capacity retention, coulombic efficiency and impedance change of the battery. Fig. 6A , Figure 6B , FIG. 7A to FIG. 7C , FIG. 8A to FIG. 8C , 9A to 9C , Fig. 10A , Fig. 10B , Fig.11A , Fig. 11B , FIG. 12A to FIG. 12C and FIG. 13A to FIG. 13C Typical results of constant current cycling and rate performance tests are shown in FIG.

[0129] The lithium rechargeable battery of the present disclosure can have various shapes, which are not particularly limited. Examples include cylindrical can shapes, soft pack shapes or coin shapes. As described above, the lithium rechargeable battery according to the present disclosure improves the life characteristics of the battery due to the improvement in the stability of SEI and / or CEI, high ion transport capacity (both FIS liquid phase and its SEI / CEI product), the reduction of the battery internal resistance, and the reduction of electrode crosstalk and other degradation mechanisms.

[0130] Although the present teachings have been described above in terms of specific embodiments, it should be understood that they are not limited to these disclosed embodiments. Many modifications and other embodiments will occur to those skilled in the art, and these modifications and other embodiments are intended to and are covered by the present disclosure.

[0131] As used herein, the term "about" indicates a value that is generally within ±5%, as appropriate (eg, a lower range limit of -5% and an upper range limit of +5%).

Claims

1. Functional interface stabilizer for battery, comprising: organic non-aqueous solvent; and A lithium salt that is compatible with the organic non-aqueous solvent.

2. The functional interface stabilizer according to claim 1, wherein the lithium salt has a solution concentration of about 0.1 M to about 8 M.

3. The functional interface stabilizer according to claim 1, wherein the organic non-aqueous solvent comprises 1,2-dimethoxyethane (DME), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), dimethyl sulfide (DMS), fluoroethylene carbonate (FEC), dimethyl sulfoxide (DMSO), dimethyl methylphosphonate (DMMPh), trimethyl phosphate (TMP), tris(trimethylsilyl)phosphite (TMSPi), dioxolane (DOL), 1,1-diethoxy At least one of ethane (DEE), tetrahydrofuran (THF), triphenyl phosphate (TPhP), tri(2,2,2-trifluoroethyl) orthoformate (TFEO), vinylene carbonate (VC), triethyl phosphate (TEP), sulfolane (SL), methyl 1,1,2,2-tetrafluoroethyl ether (TFME), methyl β-L-fucopyranoside (MFB), 1,2-(1,1,2,2-tetrafluoroethoxy)ethane, 1,1,2,2-tetrafluoroethyl-1H,1H,5H-octafluoropentyl ether or acetonitrile.

4. The functional interface stabilizer according to claim 1, wherein the lithium salt comprises lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluoromethanesulfonyl)imide (LiFSI), lithium fluoride (LiF), lithium nitrate (LiNO 3 ), lithium difluoro(oxalate)borate (LiDFOB), lithium iodide (LiI), lithium difluorophosphate (LiPO 2 F 2 ) or lithium hexafluorophosphate (LiPF 6 ) at least one of. 5.Battery, include: anode; cathode; Diaphragm; Functional interfacial stabilizer with organic non-aqueous solvent; as well as A lithium salt that is compatible with the organic non-aqueous solvent.

6. The battery of claim 5, wherein the lithium salt has a solution concentration of about 0.1 M to about 8 M.

7. The battery according to claim 5, wherein the non-aqueous solvent comprises 1,2-dimethoxyethane (DME), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), dimethyl sulfide (DMS), fluoroethylene carbonate (FEC), dimethyl sulfoxide (DMSO), dimethyl methylphosphonate (DMMPh), trimethyl phosphate (TMP), tris(trimethylsilyl)phosphite (TMSPi), dioxolane (DOL), 1,1-diethoxyethane (D At least one of tetrafluoroethylene (EE), tetrahydrofuran (THF), triphenyl phosphate (TPhP), tri(2,2,2-trifluoroethyl) orthoformate (TFEO), vinylene carbonate (VC), triethyl phosphate (TEP), sulfolane (SL), methyl 1,1,2,2-tetrafluoroethyl ether (TFME) or methyl β-L-fucopyranoside (MFB), 1,2-(1,1,2,2-tetrafluoroethoxy)ethane, 1,1,2,2-tetrafluoroethyl-1H,1H,5H-octafluoropentyl ether or acetonitrile.

8. The battery according to claim 5, wherein the lithium salt comprises lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluoromethanesulfonyl)imide (LiFSI), lithium fluoride (LiF), lithium nitrate (LiNO 3 ), lithium difluoro(oxalate)borate (LiDFOB), lithium iodide (LiI), lithium difluorophosphate (LiPO 2 F 2 ) or lithium hexafluorophosphate (LiPF 6 ) at least one of.

9. The battery of claim 5 further comprising a solid electrolyte interface on the anode surface.

10. The battery of claim 9, wherein the solid electrolyte interface on the anode surface is mechanically adhered to the separator.

11. The battery of claim 5 further comprising a cathode electrolyte interface on the cathode surface.

12. The battery of claim 11 wherein the cathode electrolyte interface on the cathode surface is mechanically adhered to the separator.

13. The lithium battery according to claim 5, wherein the separator is selected from the group consisting of polyethylene, polypropylene, polyolefin, microporous membrane, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, woven fabric, glass fiber woven fabric, polyethylene terephthalate fiber woven fabric, cellulose, aramid fiber, other organic or synthetic fibers, ceramic, composite polymer-ceramic solid electrolyte or a polymer film or a single or multilayer film of a combination thereof.

14. The lithium battery according to claim 5, wherein the cathode is selected from lithium cobalt phosphate (LiCoPO 4 ), lithium iron phosphate (LiFePO 4 ) and lithium metal oxide (LiMeO x ), wherein Me is one or more metals selected from nickel (Ni), cobalt (Co), manganese (Mn), aluminum (Al), Li and O represent one or more corresponding lithium atoms and oxygen atoms, and x represents the number of oxygen atoms. For example, LiNi is usually selected. 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) is used as a favorable cathode active material. The cathode may also be selected from the group consisting of any other suitable spinel, olivine, sulfide, selenide, halide or combination thereof with or without lithium.

15. The lithium battery according to claim 5, wherein the anode is selected from the group consisting of: carbon-based anode active materials, graphite carbon, carbon fibers, silicon oxide, pure silicon, silicon-carbon composites, lithium metal, lithium alloys or other suitable anode materials or combinations thereof.

16. A method for preparing a functional interface stabilizer, the method include: providing an organic non-aqueous solvent; adding a lithium salt to the organic non-aqueous solvent; as well as The organic nonaqueous solvent and the lithium salt are mixed to form a solution.

17. The method according to claim 16, further comprising: The following steps are involved: adding an additive to the solution; and The solution is mixed until the additive is dissolved or homogenized.

18. The method of claim 17, wherein the additive is an auxiliary salt.

19. The method according to claim 16, further comprising: The following steps are involved: adding a diluent to the solution; as well as The solution was mixed until the diluent was homogenous.

20. The method of claim 17, wherein the diluent is a co-solvent.

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