A lithium metal for suppressing gas production, a lithium-ion battery electrolyte, lithium metal, and a lithium-ion battery.

Abstract

This invention provides a lithium metal electrolyte for suppressing gas production, as well as lithium metal and lithium-ion batteries, belonging to the field of lithium-ion battery technology. The electrolyte of this invention includes lithium salt, organic solvent, and additives. This invention uses organosilicon additives as "molecular decoupling agents," which can simultaneously passivate the positive electrode surface, reconstruct a robust and highly ionicly conductive negative electrode interface, and capture and oligomerize key shuttle species at the source, causing them to lose their redox activity, thereby blocking the chain reaction of gas generation. Soft-pack batteries prepared with this electrolyte show a reduction of approximately 90% in gas production for lithium metal batteries and approximately 95% in lithium-ion batteries after one month of storage at high temperature and 100% SOC. No gas production is observed in lithium metal and lithium-ion batteries after one month of storage at high temperature and 50% SOC, solving the industry problem of severe gas production in lithium metal and lithium-ion batteries under high temperature and high charge conditions.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a lithium metal for suppressing gas production, a lithium-ion battery electrolyte, lithium metal, and a lithium-ion battery. Background Technology

[0002] Currently, the commercialization of lithium-ion and lithium metal batteries is hampered by severe gas generation issues, especially at high temperatures and high state of charge (SOC). Gas accumulation leads to battery expansion, increased internal pressure, interface deterioration, and even the risk of thermal runaway. Current research generally suggests that gas generation is closely related to electrolyte decomposition at high voltages and side reactions at the electrode-electrolyte interface. Specifically, the crosstalk and migration of byproducts between the positive and negative electrodes reduces the stability of the positive and negative electrode interface at high temperatures, catalyzing interface dissolution and gas generation.

[0003] Furthermore, while fluorocarbonate solvents help form a stable solid-state electrolyte interface (SEI), they are prone to self-polymerization under Lewis acid catalysis (such as PF5), producing gases such as CO2. Currently, there are no technologies that can effectively suppress gas generation in batteries using additives. Summary of the Invention

[0004] In view of this, the present invention provides a lithium metal for suppressing gas generation, a lithium-ion battery electrolyte, and a lithium metal and lithium-ion battery. The present invention uses a silicon-nitrogen-containing compound as a "molecular decoupling agent" to disrupt crosstalk gas generation between the positive and negative electrodes, which can lead to battery expansion, increased internal pressure, interface deterioration, and even the risk of thermal runaway. Its molecular structure achieves a multi-target mechanism, passivating the cathode surface to inhibit transition metal dissolution, while simultaneously participating in the formation of a robust ion-conducting solid electrolyte interface on the anode. Crucially, the silicon-nitrogen-containing compound can effectively isolate and eliminate key soluble intermediates on the oligomeric anode, rendering them inactive and preventing their shuttle behavior, thereby blocking the chain reaction of gas generation and suppressing gas generation in the battery.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a lithium metal for suppressing gas production and a lithium-ion battery electrolyte, comprising lithium salt, organic solvent, and additives, wherein the additives include silicon-nitrogen compounds.

[0007] Furthermore, the silicon-nitrogen compounds include one or more of N,N-diethyltrimethylsilaneamine (EMSA), 3-(trimethylsilyl)-2-oxazolidinone (TMS-ON), and 1-(trimethylsilyl)imidazolium (1-TMSI).

[0008] Furthermore, the mass percentage of the silicon nitride compound is 0.1% to 5%.

[0009] Furthermore, the organic solvent includes one or more of fluorinated cyclic carbonate solvents and linear carbonate solvents.

[0010] Furthermore, the fluorinated cyclic carbonate solvent includes one or more of fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), and trifluoropropylene carbonate (TFPC), and the fluorinated cyclic carbonate solvent accounts for 10% to 50% of the mass of the electrolyte.

[0011] Furthermore, the linear carbonate solvent includes one or more of diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC), and the linear carbonate solvent accounts for 50% to 90% of the mass of the electrolyte.

[0012] Furthermore, the lithium salt includes one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium dioxaborate (LiBOB), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium hexafluoroarsenate (LiAsF6).

[0013] Furthermore, the concentration of the lithium salt is 0.3-4.5 mol / L.

[0014] Furthermore, the lithium battery electrolyte also includes film-forming additives, which include one or more of sulfonates, haloesters, sulfites, borates, and phosphates, and the mass percentage of the film-forming additives is 0.1% to 5%.

[0015] The present invention also provides a lithium metal comprising the electrolyte and a lithium-ion battery.

[0016] Compared with existing technologies, the present invention has the following beneficial effects: For soft-pack batteries prepared using the electrolyte provided by the present invention, the gas production of lithium metal batteries can be reduced by approximately 90% after one month of storage at high temperature and 100% SOC, and no gas production can be achieved after one month of storage at high temperature and 50% SOC. For lithium-ion batteries, the gas production can be reduced by approximately 95% after one month of storage at high temperature and 100% SOC, and no gas production can be achieved after one month of storage at high temperature and 50% SOC. Detailed Implementation

[0017] This invention provides a lithium metal for suppressing gas production and a lithium-ion battery electrolyte, comprising lithium salt, organic solvent, and additives, wherein the additives include silicon-nitrogen compounds.

[0018] In some embodiments of the present invention, the silicon-nitrogen compound includes one or more of N,N-diethyltrimethylsilaneamine (EMSA), 3-(trimethylsilyl)-2-oxazolidinone (TMS-ON), and 1-(trimethylsilyl)imidazolium (1-TMSI). Preferably, the silicon-nitrogen compound is 3-(trimethylsilyl)-2-oxazolidinone (TMS-ON).

[0019] In some embodiments of the present invention, the silicon nitride compound accounts for 0.1% to 5% by mass. Preferably, the silicon nitride compound accounts for 0.3% by mass.

[0020] In some embodiments of the present invention, the additive further includes 1,3-propanesulfonate lactone (PS). During the first charge and discharge of the battery, 1,3-propanesulfonate lactone (PS) preferentially undergoes reduction and decomposition on the negative electrode surface before solvent molecules, participating in the formation of a solid electrolyte interphase (SEI) film.

[0021] Among them, silicon-nitrogen additives can precisely identify and chemically capture soluble organic lithium intermediates (such as alkoxy lithium) generated by the incomplete reduction of organic solvents at the negative electrode through specific functional groups in their molecules. This induces these intermediates to undergo oligomerization, transforming them from migratable small molecules into insoluble high-molecular-weight polymers, thereby physically blocking their "shuttle" path from the negative electrode to the positive electrode. This completely severs the "cross-talk" cycle that leads to the generation of large amounts of gas; this effect is the result of the synergistic effect of lithium salts, organic solvents, and additives.

[0022] This invention reveals a mutually accelerating degradation pathway of gas generation in lithium metal batteries by combining differential electrochemical mass spectrometry, nuclear magnetic resonance spectroscopy, and theoretical calculations. The study found that metastable organic lithium salts generated at the negative electrode shuttle to the positive electrode and are oxidized to CO2. Simultaneously, positive electrode derivatives migrate to the negative electrode, disrupting the SEI structure and further promoting the generation of gas precursors. This crosstalk between electrodes is the main mechanism for the continuous generation of gas.

[0023] Based on this mechanism, this invention designs a multifunctional organosilicon additive as a "molecular decoupling agent" that can simultaneously passivate the positive electrode surface, reconstruct a robust and highly ionicly conductive negative electrode interface, and capture and oligomerize key shuttle species at the source, causing them to lose their redox activity, thereby blocking the chain reaction of gas generation.

[0024] In some embodiments of the present invention, the organic solvent includes one or more of fluorinated cyclic carbonate solvents and linear carbonate solvents. Preferably, the organic solvent is a fluorinated cyclic carbonate solvent. In some embodiments of the present invention, the fluorinated cyclic carbonate solvent includes one or more of fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), and trifluoropropylene carbonate (TFPC), and the fluorinated cyclic carbonate solvent accounts for 10% to 50% of the electrolyte by mass. Preferably, the fluorinated cyclic carbonate solvent accounts for 25% of the electrolyte by mass.

[0025] In some embodiments of the present invention, the linear carbonate solvent includes one or more of diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC), and the linear carbonate solvent accounts for 50% to 90% of the electrolyte by mass. Preferably, the linear carbonate solvent accounts for 75% of the electrolyte by mass.

[0026] In some embodiments of the present invention, the lithium salt includes one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium difluorooxalate borate (LiBOB), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluoroarsenate (LiAsF6), lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP).

[0027] In some embodiments of the present invention, the concentration of the lithium salt is 0.3-4.5 mol / L. Preferably, the concentration of the lithium salt is 1 mol / L.

[0028] In some embodiments of the present invention, the lithium battery electrolyte further includes film-forming additives, which include one or more of sulfonates, haloesters, sulfites, borates, and phosphates.

[0029] The sulfonate compounds include, but are not limited to, any one of methanesulfonate, p-toluenesulfonate, and trifluoromethanesulfonate.

[0030] The haloesters include, but are not limited to, any one of ethyl chloroacetate, ethyl bromoacetate, and iodomethane.

[0031] The sulfites include, but are not limited to, any one of lithium sulfite, lithium bisulfite, and lithium metabisulfite.

[0032] The borates include, but are not limited to, any one of lithium tetraborate and lithium tetraphenylborate.

[0033] The phosphates include, but are not limited to, any one of lithium phosphate, lithium hydrogen phosphate, and lithium dihydrogen phosphate.

[0034] In some embodiments of the present invention, the film-forming additive accounts for 0.1% to 5% by mass. Preferably, the film-forming additive accounts for 0.3% by mass.

[0035] The present invention also provides a lithium metal comprising the electrolyte and a lithium-ion battery.

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] Unless otherwise specified, the test methods or experimental methods described in the following examples are all conventional methods; unless otherwise specified, the raw materials and additives are obtained from conventional commercial sources or prepared by conventional methods.

[0038] Example 1

[0039] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and additives; the lithium salt being lithium hexafluorophosphate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene difluorocarbonate (DFEC) solvent and ethyl methyl carbonate (EMC); and the additives being 3-trimethylsilyl-2-oxazolidinone (TMSON) and 1,3-propanesulfonate lactone (PS).

[0040] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0041] Step 1: Stir the mixture at room temperature until it is miscible with respect to DFEC:EMC in a mass ratio of 1:2 to obtain mixture A;

[0042] Step 2: Add lithium hexafluorophosphate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0043] Step 3: Add 0.3% TMSON, 0.3% PS, 1% LiODFB, and 1% LiDFP to mixture B, respectively, and stir at room temperature for 12 h. After mixing evenly, a lithium metal that inhibits gas production and a lithium-ion battery electrolyte are obtained.

[0044] A method for preparing a lithium metal battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: using a high-specific-capacity cathode material (Ni... 0.8 Co 0.1 Mn 0.1 (NCM811). The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and punched, then transferred to a glove box for later use. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the positive electrode aluminum tabs are welded on. Commercial lithium foil (20 µm thick) is used. In the glove box, the lithium foil is lightly rolled using a clean roller press to make its surface flat and dense, reducing the initial specific surface area, and the negative electrode nickel tab is welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The separators are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. After top sealing, the battery cell is placed in a high vacuum (< -0.1 MPa), high temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the battery cell through the injection port.

[0045] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 5 ml and 0 ml, respectively.

[0046] Example 2

[0047] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and additives; the lithium salt being lithium tetrafluoroborate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene difluorocarbonate (DFEC) solvent and ethyl methyl carbonate (EMC); and the additives being N,N-diethyltrimethylsilaneamine (EMSA) and 1,3-propanesulfonate lactone (PS).

[0048] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0049] Step 1: Stir the mixture at room temperature until it is miscible with respect to DFEC:EMC by mass ratio of 1:2 to obtain mixture A;

[0050] Step 2: Add lithium tetrafluoroborate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0051] Step 3: Add 0.3% EMSA, 0.3% PS, 1% LiODFB and 1% LiDFP to mixture B, respectively, and stir at room temperature for 12 h. After mixing evenly, a lithium metal that inhibits gas production and a lithium-ion battery electrolyte are obtained.

[0052] A method for preparing a lithium metal battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: using a high-specific-capacity cathode material (Ni... 0.8 Co 0.1 Mn 0.1 (NCM811). The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and punched, then transferred to a glove box for later use. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the positive electrode aluminum tabs are welded on. Commercial lithium foil (20 µm thick) is used. In the glove box, the lithium foil is lightly rolled using a clean roller press to make its surface flat and dense, reducing the initial specific surface area, and the negative electrode nickel tab is welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The separators are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. After top sealing, the battery cell is placed in a high vacuum (< -0.1 MPa), high temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the battery cell through the injection port.

[0053] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 5 ml and 0 ml, respectively.

[0054] Example 3

[0055] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and additives; the lithium salt being lithium tetrafluoroborate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene carbonate (EC) solvent and ethyl methyl carbonate (EMC); and the additives being N,N-diethyltrimethylsilaneamine (EMSA) and 1,3-propanesulfonate lactone (PS).

[0056] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0057] Step 1: Stir the mixture at room temperature until it is miscible with respect to EC:EMC by mass ratio of 1:2 to obtain mixture A;

[0058] Step 2: Add lithium tetrafluoroborate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0059] Step 3: Add 0.3% EMSA, 0.3% PS, 1% LiODFB and 1% LiDFP to mixture B, respectively, and stir at room temperature for 12 h. After mixing evenly, a lithium metal that inhibits gas production and a lithium-ion battery electrolyte are obtained.

[0060] A method for preparing a lithium metal battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: using a high-specific-capacity cathode material (Ni... 0.8 Co 0.1 Mn 0.1 (NCM811). The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and punched, then transferred to a glove box for later use. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the positive electrode aluminum tabs are welded on. Commercial lithium foil (20 µm thick) is used. In the glove box, the lithium foil is lightly rolled using a clean roller press to make its surface flat and dense, reducing the initial specific surface area, and the negative electrode nickel tab is welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The separators are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. After top sealing, the battery cell is placed in a high vacuum (< -0.1 MPa), high temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the battery cell through the injection port.

[0061] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 35 ml and 0 ml, respectively.

[0062] Example 4

[0063] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and additives; the lithium salt being lithium tetrafluoroborate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene carbonate (EC) solvent, ethyl methyl carbonate (EMC), and difluoroethylene carbonate (DFEC); and the additives being N,N-diethyltrimethylsilaneamine (EMSA) and 1,3-propanesulfonate lactone (PS).

[0064] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0065] Step 1: Stir the mixture at room temperature until it is miscible with respect to EC:EMC by mass ratio of 1:2 to obtain mixture A;

[0066] Step 2: Add lithium tetrafluoroborate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0067] Step 3: Add 0.3% by mass of EMSA, 0.3% by mass of PS, 0.3% by mass of DFEC, 1% by mass of LiODFB, and 1% by mass of LiDFP to mixture B, respectively. Stir at room temperature for 12 h. After mixing evenly, a lithium metal that inhibits gas production and a lithium-ion battery electrolyte are obtained.

[0068] A method for preparing a lithium metal battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: using a high-specific-capacity cathode material (Ni... 0.8 Co 0.1 Mn 0.1(NCM811). The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and punched, then transferred to a glove box for later use. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the positive electrode aluminum tabs are welded on. Commercial lithium foil (20 µm thick) is used. In the glove box, the lithium foil is lightly rolled using a clean roller press to make its surface flat and dense, reducing the initial specific surface area, and the negative electrode nickel tab is welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The separators are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. After top sealing, the battery cell is placed in a high vacuum (< -0.1 MPa), high temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the battery cell through the injection port.

[0069] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 29 ml and 0 ml, respectively.

[0070] Example 5

[0071] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and additives; the lithium salt being lithium hexafluorophosphate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene carbonate (EC) solvent, ethyl methyl carbonate (EMC), and difluoroethylene carbonate (DFEC); and the additives being N,N-diethyltrimethylsilaneamine (EMSA) and 1,3-propanesulfonate lactone (PS).

[0072] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0073] Step 1: Stir the mixture at room temperature until it is miscible with respect to EC:EMC by mass ratio of 1:2 to obtain mixture A;

[0074] Step 2: Add lithium hexafluorophosphate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0075] Step 3: Add 0.3% by mass of EMSA, 0.3% by mass of PS, 0.3% by mass of DFEC, 1% by mass of LiODFB, and 1% by mass of LiDFP to mixture B, respectively. Stir at room temperature for 12 h. After mixing evenly, a lithium metal that inhibits gas production and a lithium-ion battery electrolyte are obtained.

[0076] A method for preparing a lithium metal battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: using a high-specific-capacity cathode material (Ni... 0.8 Co 0.1 Mn 0.1 (NCM811). The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and punched, then transferred to a glove box for later use. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the positive electrode aluminum tabs are welded on. Commercial lithium foil (20 µm thick) is used. In the glove box, the lithium foil is lightly rolled using a clean roller press to make its surface flat and dense, reducing the initial specific surface area, and the negative electrode nickel tab is welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The separators are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. After top sealing, the battery cell is placed in a high vacuum (< -0.1 MPa), high temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the battery cell through the injection port.

[0077] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40℃ for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 25 ml and 0 ml, respectively.

[0078] Example 6

[0079] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and an additive; the lithium salt being lithium tetrafluoroborate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene difluorocarbonate (DFEC) solvent and ethyl methyl carbonate (EMC); and the additive being 1,3-propanesulfonate lactone (PS).

[0080] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0081] Step 1: Stir the mixture at room temperature until it is miscible with respect to DFEC:EMC by mass ratio of 1:2 to obtain mixture A;

[0082] Step 2: Add lithium tetrafluoroborate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0083] Step 3: Add 0.3% PS, 1% LiODFB, and 1% LiDFP to mixture B, respectively, and stir at room temperature for 12 h. After mixing evenly, a lithium metal that inhibits gas production and a lithium-ion battery electrolyte are obtained.

[0084] A method for preparing a lithium metal battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: using a high-specific-capacity cathode material (Ni... 0.8 Co 0.1 Mn 0.1 (NCM811). The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and punched, then transferred to a glove box for later use. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the positive electrode aluminum tabs are welded on. Commercial lithium foil (20 µm thick) is used. In the glove box, the lithium foil is lightly rolled using a clean roller press to make its surface flat and dense, reducing the initial specific surface area, and the negative electrode nickel tab is welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The separators are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. After top sealing, the battery cell is placed in a high vacuum (< -0.1 MPa), high temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the battery cell through the injection port.

[0085] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 21 ml and 0 ml, respectively.

[0086] Example 7

[0087] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and additives; the lithium salt being lithium hexafluorophosphate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene difluorocarbonate (DFEC) solvent and ethyl methyl carbonate (EMC); and the additives being 1-(trimethylsilyl)imidazolium (1-TMSI) and 1,3-propanesulfonate lactone (PS).

[0088] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0089] Step 1: Stir the mixture at room temperature until it is miscible with respect to DFEC:EMC in a mass ratio of 1:2 to obtain mixture A;

[0090] Step 2: Add lithium hexafluorophosphate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0091] Step 3: Add 0.3% by mass of 1-TMSI, 0.3% by mass of PS, 1% by mass of LiODFB, and 1% by mass of LiDFP to mixture B, respectively, and stir at room temperature for 12 h. After mixing evenly, a lithium metal that inhibits gas production and a lithium-ion battery electrolyte are obtained.

[0092] A method for preparing a lithium metal battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: using a high-specific-capacity cathode material (Ni... 0.8 Co 0.1 Mn 0.1 (NCM811). The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and punched, then transferred to a glove box for later use. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the positive electrode aluminum tabs are welded on. Commercial lithium foil (20 µm thick) is used. In the glove box, the lithium foil is lightly rolled using a clean roller press to make its surface flat and dense, reducing the initial specific surface area, and the negative electrode nickel tab is welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The separators are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. After top sealing, the battery cell is placed in a high vacuum (< -0.1 MPa), high temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the battery cell through the injection port.

[0093] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 5 ml and 0 ml, respectively.

[0094] Example 8

[0095] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and additives; the lithium salt being lithium hexafluorophosphate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene difluorocarbonate (DFEC) solvent and ethyl methyl carbonate (EMC); and the additives being 3-trimethylsilyl-2-oxazolidinone (TMSON) and 1,3-propanesulfonate lactone (PS).

[0096] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0097] Step 1: Stir the mixture at room temperature until it is miscible with respect to DFEC:EMC in a mass ratio of 1:2 to obtain mixture A;

[0098] Step 2: Add lithium hexafluorophosphate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0099] Step 3: Add 0.3% TMSON, 0.3% PS, 1% LiODFB, and 1% LiDFP to mixture B, respectively, and stir at room temperature for 12 h. After mixing evenly, a lithium metal that inhibits gas production and a lithium-ion battery electrolyte are obtained.

[0100] A method for preparing a lithium-ion battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: A high-specific-capacity positive electrode material (Ni0.8Co0.1Mn0.1, NCM811) is used. The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and stamped, then transferred to a glove box for later use. The electrode sheet is cut to the designed size using a die-cutting machine or laser cutting machine, and the positive electrode aluminum tabs are welded on. Graphite, conductive agent, and binder are mixed uniformly in a solvent in a mass ratio of 92:3:5. The mixture is placed in a vacuum mixer and stirred at an appropriate speed until a uniform slurry with good flowability and no particle agglomeration is formed. The obtained slurry is uniformly coated onto a copper foil current collector, with the coating thickness controlled by a doctor blade or coating machine. The coated electrode sheet is placed in an oven to dry completely to remove the solvent. After drying, the electrode sheets are compacted to the designed density using a roller press, and then punched into electrode sheets of the required size. The punched electrode sheets are further dried in a vacuum oven to completely remove moisture, and then transferred to an argon-filled glove box for storage. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the negative nickel electrode tabs are welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The electrodes are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. The top-sealed cell is placed in a high-vacuum (< -0.1 MPa), high-temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the cell through the injection port.

[0101] Two identical 7Ah lithium-ion batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume difference between the two records was 1 ml and 0 ml, respectively.

[0102] Example 9

[0103] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and additives; the lithium salt being lithium tetrafluoroborate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene difluorocarbonate (DFEC) solvent and ethyl methyl carbonate (EMC); and the additives being N,N-diethyltrimethylsilaneamine (EMSA) and 1,3-propanesulfonate lactone (PS).

[0104] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0105] Step 1: Stir the mixture at room temperature until it is miscible with respect to DFEC:EMC by mass ratio of 1:2 to obtain mixture A;

[0106] Step 2: Add lithium tetrafluoroborate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0107] Step 3: Add 0.3% EMSA, 0.3% PS, 1% LiODFB and 1% LiDFP to mixture B, respectively, and stir at room temperature for 12 h. After mixing evenly, a lithium metal that inhibits gas production and a lithium-ion battery electrolyte are obtained.

[0108] A method for preparing a lithium-ion battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: A high-specific-capacity positive electrode material (Ni0.8Co0.1Mn0.1, NCM811) is used. The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and stamped, then transferred to a glove box for later use. The electrode sheet is cut to the designed size using a die-cutting machine or laser cutting machine, and the positive electrode aluminum tabs are welded on. Graphite, conductive agent, and binder are mixed uniformly in a solvent in a mass ratio of 92:3:5. The mixture is placed in a vacuum mixer and stirred at an appropriate speed until a uniform slurry with good flowability and no particle agglomeration is formed. The obtained slurry is uniformly coated onto a copper foil current collector, with the coating thickness controlled by a doctor blade or coating machine. The coated electrode sheet is placed in an oven to dry completely to remove the solvent. After drying, the electrode sheets are compacted to the designed density using a roller press, and then punched into electrode sheets of the required size. The punched electrode sheets are further dried in a vacuum oven to completely remove moisture, and then transferred to an argon-filled glove box for storage. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the negative nickel electrode tabs are welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The electrodes are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. The top-sealed cell is placed in a high-vacuum (< -0.1 MPa), high-temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the cell through the injection port.

[0109] Two identical 7Ah lithium-ion batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 1.5 ml and 0 ml, respectively.

[0110] Example 10

[0111] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt, an organic solvent, and an additive; the lithium salt being lithium tetrafluoroborate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene difluorocarbonate (DFEC) solvent and ethyl methyl carbonate (EMC); and the additive being 1,3-propanesulfonate lactone (PS).

[0112] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0113] Step 1: Stir the mixture at room temperature until it is miscible with respect to DFEC:EMC by mass ratio of 1:2 to obtain mixture A;

[0114] Step 2: Add lithium tetrafluoroborate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0115] Step 3: Add 0.3% PS by mass, 1% LiODFB by mass, and 1% LiDFP by mass to mixture B, respectively, and stir at room temperature for 12 h. After mixing evenly, a lithium metal and a lithium-ion battery electrolyte are obtained.

[0116] A method for preparing a lithium-ion battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: A high-specific-capacity positive electrode material (Ni0.8Co0.1Mn0.1, NCM811) is used. The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and stamped, then transferred to a glove box for later use. The electrode sheet is cut to the designed size using a die-cutting machine or laser cutting machine, and the positive electrode aluminum tabs are welded on. Graphite, conductive agent, and binder are mixed uniformly in a solvent in a mass ratio of 92:3:5. The mixture is placed in a vacuum mixer and stirred at an appropriate speed until a uniform slurry with good flowability and no particle agglomeration is formed. The obtained slurry is uniformly coated onto a copper foil current collector, with the coating thickness controlled by a doctor blade or coating machine. The coated electrode sheet is placed in an oven to dry completely to remove the solvent. After drying, the electrode sheets are compacted to the designed density using a roller press, and then punched into electrode sheets of the required size. The punched electrode sheets are further dried in a vacuum oven to completely remove moisture, and then transferred to an argon-filled glove box for storage. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the negative nickel electrode tabs are welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The electrodes are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. The top-sealed cell is placed in a high-vacuum (< -0.1 MPa), high-temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the cell through the injection port.

[0117] Two identical 7Ah lithium-ion batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 22 ml and 0 ml, respectively.

[0118] Comparative Example 1

[0119] The difference from Example 1 is that the electrolyte used is a commercial electrolyte (1 M LiPF6 EC / DEC / EMC, 1:1:1).

[0120] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 40 ml and 15 ml, respectively.

[0121] Comparative Example 2

[0122] The difference from Example 1 is that the formulation used lacks 1% by mass of LiODFB and 1% by mass of LiDFP.

[0123] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 35 ml and 14 ml, respectively.

[0124] Comparative Example 3

[0125] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt and an organic solvent; the lithium salt being lithium tetrafluoroborate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene difluorocarbonate (DFEC) solvent and ethyl methyl carbonate (EMC).

[0126] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0127] Step 1: Stir the mixture at room temperature until it is miscible with respect to DFEC:EMC at a mass ratio of 1:6 to obtain mixture A;

[0128] Step 2: Add lithium tetrafluoroborate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0129] Step 3: Add 1% by mass of LiODFB and 1% by mass of LiDFP to mixture B, stir at room temperature for 12 h, and after mixing evenly, obtain a lithium metal that inhibits gas production and a lithium-ion battery electrolyte.

[0130] A method for preparing a lithium metal battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: using a high-specific-capacity cathode material (Ni... 0.8 Co 0.1 Mn 0.1(NCM811). The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and punched, then transferred to a glove box for later use. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the positive electrode aluminum tabs are welded on. Commercial lithium foil (20 µm thick) is used. In the glove box, the lithium foil is lightly rolled using a clean roller press to make its surface flat and dense, reducing the initial specific surface area, and the negative electrode nickel tab is welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The separators are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. After top sealing, the battery cell is placed in a high vacuum (< -0.1 MPa), high temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the battery cell through the injection port.

[0131] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40°C for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 30 ml and 0 ml, respectively.

[0132] Comparative Example 4

[0133] A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, the electrolyte being composed of a lithium salt and an organic solvent; the lithium salt being lithium tetrafluoroborate, lithium difluorooxalate borate (LiODFB), and lithium difluorophosphate (LiDFP); the organic solvent being ethylene difluorocarbonate (DFEC) solvent and ethyl methyl carbonate (EMC).

[0134] The specific steps of the method for preparing the lithium metal that suppresses gas production and the lithium-ion battery electrolyte are as follows (the preparation of the electrolyte is carried out in a glove box filled with argon gas):

[0135] Step 1: Stir the mixture at room temperature until it is miscible with respect to DFEC:EMC in a mass ratio of 1:2 to obtain mixture A;

[0136] Step 2: Add lithium tetrafluoroborate to mixture A at a lithium salt concentration of 1 mol / L, and stir at room temperature for 12 h to obtain mixture B;

[0137] Step 3: Add 1% by mass of LiODFB and 1% by mass of LiDFP to mixture B, stir at room temperature for 12 h, and after mixing evenly, obtain a lithium metal that inhibits gas production and a lithium-ion battery electrolyte.

[0138] A method for preparing a lithium metal battery includes lithium metal for suppressing gas production and a lithium-ion battery electrolyte. The specific steps are as follows: using a high-specific-capacity cathode material (Ni... 0.8 Co 0.1 Mn 0.1 (NCM811). The positive electrode active material, conductive agent, and binder are mixed in a ratio of 90:5:5 in N-methylpyrrolidone and ground into a uniform slurry. The slurry is uniformly coated onto an aluminum foil current collector, vacuum dried, rolled, and punched, then transferred to a glove box for later use. The electrode sheets are cut to the designed size using a die-cutting machine or laser cutter, and the positive electrode aluminum tabs are welded on. Commercial lithium foil (20 µm thick) is used. In the glove box, the lithium foil is lightly rolled using a clean roller press to make its surface flat and dense, reducing the initial specific surface area, and the negative electrode nickel tab is welded on. A ceramic-coated polyolefin separator with good electrolyte wettability, oxidation resistance, and certain mechanical strength is selected. The separators are stacked in the following order: separator, negative electrode sheet, separator, positive electrode sheet, separator… Ensure that the edges of each layer of electrode sheets are completely wrapped by the separator to prevent direct contact between the positive and negative electrodes. After top sealing, the battery cell is placed in a high vacuum (< -0.1 MPa), high temperature oven and baked for 24-48 hours. Under high vacuum conditions, a precisely metered amount of gas-suppressing electrolyte is injected into the battery cell through the injection port.

[0139] Two identical 7Ah lithium metal batteries were activated by three 0.1C charge-discharge cycles, and the volume of the batteries after activation was recorded. The batteries were then charged to 100% SOC and 50% SOC at 1C, respectively, and left to rest at 40℃ for one month. The volume and cycle number of the batteries after resting were recorded. The volume differences between the two records were 33 ml and 0 ml, respectively.

[0140] Performance testing

[0141] The performance of the electrolytes provided in the test examples and comparative examples in suppressing gas production and maintaining cycle life is shown in Table 1.

[0142] Table 1

[0143] Group Gas production at 100% SOC Gas production at 50% SOC Number of cycles after one month Example 1 5ml 0 ml 185 times Example 2 5ml 0 ml 180 times Example 3 35ml 0 ml 173 times Example 4 29ml 0 ml 95 times Example 5 25ml 0 ml 100 times Example 6 21ml 0 ml 162 times Example 7 5ml 0 ml 177 times Example 8 1ml 0 ml 240 times Example 9 1.5ml 0 ml 239 times Example 10 22ml 0 ml 150 times Comparative Example 1 40ml 15ml 40 times Comparative Example 2 35ml 14ml 44 times Comparative Example 3 30ml 0 ml 100 times Comparative Example 4 33ml 0 ml 160 times

[0144] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A lithium metal for suppressing gas production and a lithium-ion battery electrolyte, comprising a lithium salt, an organic solvent, and additives, characterized in that, The additives include silicon-nitrogen compounds.

2. The lithium metal for suppressing gas production and the lithium-ion battery electrolyte according to claim 1, comprising lithium salt, organic solvent, and additives, characterized in that, The silicon-nitrogen compounds include one or more of N,N-diethyltrimethylsilaneamine, 3-(trimethylsilyl)-2-oxazolidinone, and 1-(trimethylsilyl)imidazolium.

3. The lithium metal for suppressing gas production and the lithium-ion battery electrolyte according to claim 1, comprising lithium salt, organic solvent, and additives, characterized in that, The mass percentage of the silicon-nitrogen compounds is 0.1% to 5%.

4. The lithium metal for suppressing gas production and the lithium-ion battery electrolyte according to claim 1, comprising lithium salt, organic solvent, and additives, characterized in that, The organic solvent includes one or more of fluorinated cyclic carbonate solvents and linear carbonate solvents.

5. The lithium metal for suppressing gas production and the lithium-ion battery electrolyte according to claim 4, comprising lithium salt, organic solvent, and additives, characterized in that, The fluorinated cyclic carbonate solvent includes one or more of fluoroethylene carbonate, difluoroethylene carbonate, and trifluoropropylene carbonate, and the fluorinated cyclic carbonate solvent accounts for 10% to 50% of the mass of the electrolyte.

6. The lithium metal for suppressing gas production and the lithium-ion battery electrolyte according to claim 4, comprising lithium salt, organic solvent, and additives, characterized in that, The linear carbonate solvent includes one or more of diethyl carbonate, dimethyl carbonate, and ethyl methyl carbonate, and the linear carbonate solvent accounts for 50% to 90% of the mass of the electrolyte.

7. The lithium metal for suppressing gas production and the lithium-ion battery electrolyte according to claim 1, comprising lithium salt, organic solvent, and additives, characterized in that, The lithium salt includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium dioxaborate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium hexafluoroarsenate.

8. The lithium metal for suppressing gas production and the lithium-ion battery electrolyte according to claim 7, comprising lithium salt, organic solvent, and additives, characterized in that, The concentration of the lithium salt is 0.3-4.5 mol / L.

9. The lithium metal for suppressing gas production and the lithium-ion battery electrolyte according to claim 1, comprising lithium salt, organic solvent, and additives, characterized in that, The lithium battery electrolyte also includes film-forming additives, which include one or more of sulfonates, haloesters, sulfites, borates, and phosphates, and the mass percentage of the film-forming additives is 0.1% to 5%.

10. A lithium metal and a lithium-ion battery, characterized in that: Includes the electrolyte as described in any one of claims 1-9.