Electrolyte, battery and electric device

Abstract

The invention discloses an electrolyte, a battery and application thereof. The electrolyte comprises an aprotic organic solvent and lithium salts, wherein the lithium salts comprise high-stability organic lithium borate and high-ionic-conductivity (greater than or equal to 8mS / cm) lithium sulfimide. Wherein the high-conductivity salt is responsible for improving lithium ion transport kinetics and promoting rapid embedding of lithium ions into the positive electrode, and the organic lithium borate salt plays a dual protection role by virtue of excellent thermal stability and chemical stability, on one hand, a stable film is formed on a positive electrode interface, structural stress and damage are relieved, and vanadium dissolution is directly inhibited; on the other hand, the gas production risk of the electrolyte is reduced through the thermal stability, the internal pressure of the battery is controlled, and the vanadium dissolution driving force is indirectly reduced. The two components cooperate with each other, so that the structural integrity of the positive electrode material is protected, the improved electrolyte component reduces the increase of the internal resistance of the battery during the discharging period of the battery, and the safety and reliability of the battery in the implantable heart equipment are improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to an electrolyte, a battery, and an electrical device. Background Technology

[0002] In the field of implantable medical devices, battery technology using silver vanadium oxide (SVO) as the positive electrode material has been widely validated and has a long history of reliable use. The actual operating mode of this type of battery is characterized by the following: it operates in a monitoring standby state with extremely low current for most of the time, a process that is intermittently interrupted by high-rate pulse discharges when the device is activated. Prolonged static storage leads to a continuous increase in DC internal resistance, which in turn causes a sharp drop in operating voltage during high-rate pulse discharges, resulting in a significant voltage hysteresis effect. This phenomenon restricts the device's response performance and shortens its service life. Research data confirms a strong correlation between the cumulative increase in DC internal resistance (Rdc) and the dissolution behavior of the positive electrode material. Specifically, this manifests as the dissolution of vanadium, with the dissolved vanadium species migrating to the negative electrode surface and depositing there, continuously eroding and damaging the solid electrolyte interface film of the negative electrode, ultimately resulting in an increase in the overall internal resistance of the battery.

[0003] Because the silver lithium vanadate system is prone to vanadium dissolution, and the electrolyte affects the degree of vanadium dissolution, it leads to an increase in the internal resistance (Rdc) of the diameter. Therefore, there is an urgent need to develop an electrolyte that can effectively improve vanadium dissolution. Summary of the Invention

[0004] This application provides an electrolyte, a battery, and an electrical device, which aims to solve the problem of vanadium leaching.

[0005] This application provides an electrolyte comprising an aprotic organic solvent and a lithium salt, wherein the lithium salt comprises an organoboronate lithium salt and a sulfonylimide lithium salt with an ionic conductivity greater than or equal to 8 mS / cm.

[0006] This application's embodiments design lithium salts comprising lithium salts with different properties: lithium organoborate and lithium sulfonylimide, wherein the lithium organoborate is a highly stable lithium salt, and the lithium sulfonylimide is a lithium salt with high ionic conductivity. The highly conductive salt is responsible for improving lithium-ion transport kinetics, promoting rapid lithium-ion insertion into the positive electrode, while the lithium organoborate, with its excellent thermal and chemical stability, plays a dual protective role: on the one hand, it forms a stable film at the positive electrode interface, alleviating structural stress and damage, and directly inhibiting vanadium dissolution; on the other hand, it reduces the risk of electrolyte gas generation through its own thermal stability, controlling the battery's internal pressure and indirectly reducing the driving force for vanadium dissolution. Together, they protect the structural integrity of the positive electrode material. The improved electrolyte composition reduces the increase in battery internal resistance during discharge, improving the safety and reliability of batteries implantable in cardiac devices.

[0007] Optionally, in some embodiments of this application, the organoboronium salt includes at least one of lithium tetrafluoroborate, lithium bis(oxalate)borate, and lithium difluorooxalateborate.

[0008] The thermal decomposition temperature of the above-mentioned organoboronate lithium salts is not lower than 200℃, and they have good heat resistance, which can reduce the risk of gas generation in the electrolyte due to temperature rise.

[0009] Optionally, in some embodiments of this application, the lithium sulfonylimide salt includes at least one of lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide.

[0010] The ionic conductivity of the aforementioned high-ionic-conductivity lithium salts is not less than 8 mS·cm. -1 It can effectively alleviate the problems of positive electrode active material SM during battery discharge. x V2O y The risk of structural collapse due to lattice rearrangement.

[0011] Optionally, in some embodiments of this application, the molar ratio of the lithium organoborate salt to the lithium sulfonamide salt in the electrolyte is (0.33~3):1.

[0012] In the electrolyte, when the molar ratio of lithium organoborate to lithium sulfonylimide is less than 0.33, the excessive content of lithium sulfonylimide accelerates the instability of the positive electrode and vanadium dissolution. Conversely, when the molar ratio is greater than 3, the excessive content of lithium organoborate leads to a decrease in electrolyte conductivity, thus affecting the battery's pulse performance. Controlling the molar ratio of lithium organoborate to lithium sulfonylimide is beneficial for improving the battery's pulse capability and maintaining SM (simultaneous pulse response). x V2O y Structural stability, thereby reducing SM x V2O y Risk of vanadium leaching.

[0013] Optionally, in some embodiments of this application, the concentration of the organoboronate lithium salt in the electrolyte is 0.5 mol / L to 1.5 mol / L.

[0014] Optionally, in some embodiments of this application, the concentration of the lithium sulfonamide salt in the electrolyte is 0.5 mol / L to 1.5 mol / L.

[0015] Optionally, in some embodiments of this application, the aprotic organic solvent includes at least one of carbonate solvents and ether solvents.

[0016] Carbonate solvents have the advantages of high dielectric constant and good thermal stability, which helps to reduce the risk of gas generation caused by thermal decomposition of electrolyte; while ether solvents have low viscosity, which can improve the ion migration rate in electrolyte and are suitable for high-rate discharge.

[0017] Optionally, in some embodiments of this application, the carbonate solvent includes cyclic carbonates.

[0018] Optionally, in some embodiments of this application, the ether solvent includes at least one of straight-chain monoethers and straight-chain diethers.

[0019] Accordingly, this application also provides a battery, including a negative electrode, a positive electrode, and a separator, wherein the separator is disposed between the positive electrode and the negative electrode, and the battery further includes the aforementioned electrolyte, wherein the positive electrode comprises a general formula SM. x V2O y The transition metal oxide, wherein SM comprises at least one metal selected from groups IB to VIIB and VIII of the periodic table, wherein x is 0.30 to 2.0 and y is 4.5 to 6.0; the negative electrode comprises lithium.

[0020] The battery provided in this application embodiment uses lithium ions as the migrating ions, with the general formula SM x V2O y When transition metal oxides are used as positive electrode active materials, SM cations are reduced to metallic SM, while V... 5+ Reduced to V 4+ or V 3+ Multiple redox reactions provide multiple discharge platforms, which together contribute to the capacity, giving the battery the advantages of high-rate discharge and life indication.

[0021] Optionally, in some embodiments of this application, the transition metal oxide includes the general formula Ag. x V2O y Silver vanadium oxide.

[0022] Ag has good electrical conductivity. The addition of Ag mainly plays the role of improving the conductivity of transition metal oxides, and can also improve the structural stability of transition metal oxides.

[0023] Optionally, in some embodiments of this application, the transition metal oxide includes Cu. x1 Ag x2 V2O y Transition metal oxides, wherein x1 is 0.10~1.0 and x2 is 0.10~1.0.

[0024] Adding Cu can further stabilize the crystal structure of transition metal oxides and improve the structural stability of the material. Optionally, in some embodiments of this application, the positive electrode also includes a composite carbonaceous active material.

[0025] The introduction of composite carbonaceous active materials is beneficial to improving battery capacity.

[0026] Optionally, in some embodiments of this application, the composite carbonaceous active material comprises the chemical formula (CF) z ) n Fluorocarbon materials, where z is 0.1~1.9 and n is the number of monomer units.

[0027] Optionally, in some embodiments of this application, the positive electrode sheet includes a positive current collector and a positive electrode film layer disposed on the positive current collector, the positive electrode film layer including the transition metal oxide, binder and conductive agent.

[0028] Optionally, in some embodiments of this application, the negative electrode comprises at least one of lithium and its alloys and intermetallic compounds.

[0029] Optionally, in some embodiments of this application, the negative electrode comprises at least one of Li-Si, Li-Al, Li-B, Li-Mg, Li-Si-B alloy and intermetallic compounds.

[0030] Optionally, in some embodiments of this application, the negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on the negative current collector, the negative electrode film layer containing the lithium.

[0031] In addition, this application also provides an electrical device, which includes the battery described above.

[0032] Optionally, in some embodiments of this application, the electrical device includes an implantable medical device. Detailed Implementation

[0033] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] This application provides an electrolyte, a battery, and an electrical device. These are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative and do not impose numerical requirements or establish an order. Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0035] Some embodiments of this application provide an electrical device that uses a battery as a power source. This electrical device may be, but is not limited to, an implantable medical device. In this electrical device, the battery can serve as the driving power source. In some embodiments of this application, the electrical device is an implantable medical device, including but not limited to implantable cardioverter defibrillators (ICDs), pacemakers, and cardiac resynchronization therapy (CRT) devices.

[0036] Some embodiments of this application provide a battery, and an electrical device includes the battery. It should be noted that the battery includes, but is not limited to, at least one of battery cells, battery modules, and battery packs.

[0037] In some embodiments of this application, the battery is a single battery cell (also called a battery cell), which includes a positive electrode, a negative electrode, and a separator. Specifically, the positive electrode and the negative electrode are arranged opposite to each other, and the separator is disposed between the positive electrode and the negative electrode to prevent short circuit caused by contact between the positive electrode and the negative electrode.

[0038] Specifically, the positive electrode contains a metal oxide. Specifically, the metal oxide has the general formula SM. x V2O y The transition metal oxide, wherein SM comprises at least one metal selected from groups IB to VIIB and VIII of the periodic table, wherein x is 0.30 to 2.0 and y is 4.5 to 6.0. The negative electrode contains lithium.

[0039] In other words, SM is a transition metal. For example, SM includes at least one of iron, cobalt, nickel, copper, silver, and gold. The values ​​of x and y will vary depending on the metal contained in SM. For example, x is 0.30, 0.5, 0.8, 1.0, 1.2, 1.5, 1.8, or 2.0, and y is 4.5, 4.8, 5.0, 5.3, 5.5, 5.8, or 6.0. Optionally, the aforementioned transition metal oxides can be generated from various metal oxides, metal sulfides, and / or metal elements through chemical addition, reaction, or other close contact; optionally, the methods for forming transition metal oxides include, but are not limited to, heat treatment, sol-gel method, chemical vapor deposition, and hydrothermal synthesis.

[0040] The negative electrode contains lithium, which can be elemental lithium metal, lithium alloy, or an intermetallic compound formed by lithium and other metals.

[0041] In addition, the battery cell also includes an electrolyte, which comprises an aprotic organic solvent and a lithium salt. The lithium salt dissolves in the aprotic organic solvent and dissociates into lithium ions. The electrolyte is added to the battery cell, and the positive electrode, negative electrode, and separator are wetted by the electrolyte. During the electrochemical reaction of the battery, the electrolyte acts as a medium for the migration of lithium ions between the positive and negative electrodes.

[0042] SM x V2O y For Ag x V2O y Taking Ag as an example, x V2O y It is a classic cathode material for lithium primary batteries (disposable batteries), and its discharge process is a multi-step irreversible reaction: lithium ion intercalation leads to Ag... + It is reduced to metallic silver and extracted from the layered lattice (contributing a ~3.2V voltage plateau), subsequently V in the framework 5+ Gradually restored to V 4+ and V³ + (Corresponding to ~2.6V and ~2.2V platforms), this multi-electron transfer process allows it to release a theoretical specific capacity of up to approximately 315mAh / g; however, during charging, the reduced metallic silver is difficult to reionize, and Ag... + (Radius ~1.15 Å) and Li + The (0.76 Å) size is severely mismatched and cannot be reversibly embedded into the rearranged and contracted vanadium-oxygen framework, resulting in irreversible lattice collapse and phase transition. Therefore, this material can only be used in primary batteries and cannot achieve effective cyclic charging.

[0043] In some embodiments of this application, the transition metal oxide includes the general formula Ag. x V2O yThe silver vanadium oxide (SVO) is used. In this case, SM is silver (Ag). Ag has good electrical conductivity, and the addition of Ag mainly improves the conductivity of the transition metal oxide, while also improving its structural stability. According to the general formula Ag... x V2O y The different values ​​of x and y in the formula result in different phases for silver vanadium oxide. For example, when x = 0.35 and y = 5.8 in the general formula, the silver vanadium oxide is a β phase; when x = 0.80 and y = 5.40, it is a γ phase; and when x = 1.0 and y = 5.5, it is an ε phase. Silver vanadium oxide can be a single-phase silver vanadium oxide or a mixture of multiple phases of silver vanadium oxide.

[0044] In some embodiments of this application, the transition metal oxide includes Cu. x1 Ag x2 V2O y The transition metal oxides are used, where x1 is 0.10~1.0 and x2 is 0.10~1.0. In this case, SM includes silver (Ag) and copper (Cu). Both Ag and Cu have good electrical conductivity, and the introduction of Cu, in particular, can improve the lattice structure of the transition metal oxide and enhance the structural stability of the material. x1 Ag x2 V2O y In CSVO, y represents the oxygen content. The precise stoichiometric ratio of oxygen in CSVO can vary depending on whether the material is prepared in an oxidizing atmosphere (e.g., air or oxygen) or an inert atmosphere (e.g., argon, nitrogen, and helium). As an example, CSVO is Cu. 0.16 Ag 0.67 V2O 5.5 , or CSVO is Cu 0.5 Ag 0.5 V2O 5.75 .

[0045] In some embodiments of this application, the positive electrode sheet further includes a composite carbonaceous active material. A composite carbonaceous active material refers to a functional material formed by combining or modifying carbonaceous materials with other functional components. Optionally, the carbonaceous material includes graphite and non-graphite forms of carbon, where the non-graphite form of carbon can be coke, charcoal, or activated carbon. The addition of a composite carbonaceous active material can improve the battery's capacity.

[0046] In some embodiments of this application, the composite carbonaceous active material comprises (CF) z ) nFluorocarbon materials are a class of carbon-containing materials formed by fluorinating carbonaceous materials (such as graphite, graphene, carbon nanotubes, etc.) with carbon dioxide (C₂). The z value ranges from 0.1 to 1.9, and n represents the number of monomer units. Carbon derivatives with F bonds. The chemical formula of fluorinated carbon materials is (CF₂). z ) n The value of z ranges from 0.1 to 1.9, depending on the precursor and degree of fluorination, while n refers to the number of monomer units. For example, z can be 0.1, 0.3, 0.5, 0.8, 1.0, 1.2, 1.5, 1.8, or 2.0. Fluorinated carbon materials can gradually defluorinate during battery discharge to form metallic carbon (C), creating a conductive carbon layer.

[0047] In some embodiments of this application, the positive electrode sheet includes a positive electrode film layer, which comprises a transition metal oxide and further includes a binder and a conductive agent. Optionally, the binder includes a fluoropolymer powder, such as at least one selected from polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene tetrafluoroethylene (ETFE), polyamide, and polyimide. Optionally, the conductive agent includes at least one selected from acetylene black, carbon black, graphite, and metal powder, wherein the metal powder includes, but is not limited to, at least one selected from powdered nickel, aluminum, titanium, and stainless steel. In the positive electrode film layer, the mass percentage of the binder is 1 wt% to 10 wt%, and the mass percentage of the conductive agent is 1 wt% to 10 wt%.

[0048] In some embodiments of this application, the positive electrode further includes a positive current collector, and the positive electrode film layer is disposed on the positive current collector. The positive current collector can be a foil or a mesh, and is not limited thereto. The positive electrode film layer is disposed on the positive current collector, which can be disposed on one side of the positive current collector or on both sides of the positive current collector, that is, the positive current collector is located between two positive electrode film layers. The positive current collector is a metal, and the material of the positive current collector includes, but is not limited to, stainless steel, titanium, tantalum, platinum, gold, aluminum, cobalt-nickel alloy, and at least one alloy containing nickel, chromium, and molybdenum. Optionally, the positive current collector includes a titanium layer and an iridium thin layer or a platinum thin layer applied thereon. In preparing the positive electrode, a positive electrode slurry is first prepared by mixing a transition metal oxide, a composite carbonaceous active material, a conductive agent, and a binder with a solvent. The positive electrode slurry is then applied to the positive current collector by coating, rolling, or other methods to obtain the positive electrode, also known as a positive electrode sheet.

[0049] In some embodiments of this application, the negative electrode includes a negative electrode film layer containing lithium. Optionally, the negative electrode film layer contains at least one of lithium and its alloys and intermetallic compounds. The negative electrode film layer contains a negative electrode active material, which can be elemental lithium, a lithium-containing alloy, or a lithium-containing intermetallic compound. Optionally, the negative electrode film layer contains at least one of Li-Si alloy, Li-Al alloy, Li-B alloy, Li-Mg alloy, Li-Si-B alloy, Li-Si intermetallic compound, Li-Al intermetallic compound, Li-B intermetallic compound, Li-Mg intermetallic compound, and Li-Si-B intermetallic compound. As an example, the negative electrode film layer contains a Li-Al alloy (i.e., a lithium-aluminum alloy). The higher the weight content of aluminum in the lithium-aluminum alloy, the lower the energy density of the battery.

[0050] In some embodiments of this application, the negative electrode further includes a negative electrode current collector, and the negative electrode film layer is disposed on the negative electrode current collector. Optionally, the negative electrode film layer is a thin metal sheet or foil of lithium material, which is pressed or wound on the negative electrode current collector to form the negative electrode. In one example, the negative electrode current collector is made of nickel.

[0051] In some embodiments of this application, the separator is made of an electrically insulating material that does not chemically react with either the positive or negative electrode active material, and is also chemically insoluble in the electrolyte. Typically, the separator has sufficient porosity to allow the electrolyte to flow through it during the electrochemical reactions of the battery. Exemplarily, the separator material includes fabrics woven from fluoropolymer fibers, including but not limited to polyvinylidene fluoride, polyethylene tetrafluoroethylene, and polyethylene trifluorochloroethylene, used alone or in combination with fluoropolymer microporous membrane laminations, polypropylene, polyethylene, glass fiber materials, ceramics, etc.

[0052] Some embodiments of this application also provide an electrolyte comprising an aprotic organic solvent and a lithium salt, wherein the lithium salt comprises an organoboronate lithium salt and a sulfonylimide lithium salt with an ionic conductivity greater than or equal to 8 mS / cm.

[0053] The lithium salt includes at least two different lithium salts, wherein the first lithium salt is a highly stable organoboronate lithium salt and the second lithium salt is a sulfonylimide lithium salt with high ionic conductivity (greater than or equal to 8 mS / cm).

[0054] Two lithium salts, based on their unique molecular structures, work synergistically to achieve stable and efficient high-rate pulse performance in lithium-silver vanadate batteries. Specifically, the high stability of organoboronate lithium salts stems from their electron-deficient boron centers and rigid chelate structure: boron atoms, as strong Lewis acid sites, readily coordinate with trace proton impurities in the electrolyte or free oxygen atoms on the cathode surface, preferentially undergoing controlled decomposition at the cathode interface to form a dense, stable cathode electrolyte interface film rich in inorganic components such as LiF and boron oxanes. This interface film not only physically isolates the electrolyte from direct contact with the highly active silver vanadate cathode material, which is prone to lattice rearrangement and vanadium dissolution, effectively buffering structural stress during discharge, but also chemically anchors dissolved vanadium species, directly inhibiting vanadium migration. Furthermore, the high bond energies of the CO and BO bonds in organoboronate lithium salts result in excellent thermodynamic stability of their overall molecular framework, significantly suppressing oxidative decomposition and gas production of the electrolyte at high potentials and temperatures, thereby controlling the internal pressure of the battery and ensuring the long-term stability of the aforementioned interface film. Meanwhile, the high ionic conductivity of lithium sulfonylimide salts stems from their molecular structure: the sulfonyl group (-SO2-) has a strong electron-withdrawing effect, resulting in a high degree of delocalization of the anionic charge, which significantly weakens the lithium-ion (Li) attraction. + The electrostatic interaction between the ions and anions facilitates their dissociation in aprotic solvents, forming a large number of freely migrating Li₂. + This ensures the electrolyte possesses excellent bulk ionic conductivity and rapid interfacial ion transport kinetics, crucial for meeting the instantaneous high-current pulse demands of implantable medical devices such as pacemakers. In summary, the highly conductive salt ensures rapid ion supply and response speed, while the highly stable salt constructs and maintains a robust cathode / electrolyte interface. The synergistic effect of these two components not only significantly reduces the increase in internal resistance caused by interfacial deterioration during discharge but also fundamentally improves the structural integrity, storage reliability, and long-term safety of the silver vanadate-based lithium primary battery under harsh pulse conditions, meeting the extreme power system requirements of implantable cardiac electronic devices.

[0055] This application optimizes the lithium salt composition in the electrolyte by designing lithium salts with different properties: highly stable organoboronate lithium salt and high ionic conductivity (greater than or equal to 8 mS / cm) sulfonylimide lithium salt. The high ionic conductivity sulfonylimide lithium salt enhances lithium-ion transport kinetics, promoting rapid lithium-ion insertion into the positive electrode. The highly stable organoboronate lithium salt, with its excellent thermal and chemical stability, provides dual protection: firstly, it forms a stable film at the positive electrode interface, alleviating structural stress and damage, and directly inhibiting vanadium dissolution; secondly, its thermal stability reduces the risk of electrolyte gas generation, controls battery internal pressure, and indirectly reduces the driving force for vanadium dissolution. Together, they protect the structural integrity of the positive electrode material. The improved electrolyte composition reduces the increase in battery internal resistance during discharge, improving the safety and reliability of batteries implantable in cardiac devices.

[0056] This application proposes an innovative composite lithium salt electrolyte solution to address the core problem of vanadium dissolution and structural collapse caused by lattice rearrangement in vanadium-based cathode materials during discharge and harsh environments (high-temperature storage).

[0057] In some embodiments of this application, the organoborate lithium salt includes at least one of lithium tetrafluoroborate, lithium bis(oxalato)borate, and lithium difluorooxalatoborate. The thermal decomposition temperature of lithium tetrafluoroborate (LiBF4) is approximately 293°C, that of lithium bis(oxalato)borate (LiBOB) is approximately 300°C, and that of lithium difluorooxalatoborate (LiDFOB) is approximately 240°C. The thermal decomposition temperatures of the aforementioned organoborate lithium salts are all above 200°C, exhibiting good heat resistance, thus reducing the risk of gas generation in the electrolyte due to temperature rise.

[0058] In some embodiments of this application, the lithium sulfonylimide salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide. The ionic conductivity of lithium bis(trifluoromethanesulfonyl)imide (LiTFSi) is 10.55 mS·cm. -1 The ionic conductivity of lithium bis(fluorosulfonyl)imide (LiFSi) is 11.44 mS·cm. -1 The ionic conductivity of the aforementioned high-ionic-conductivity lithium salts is not less than 8.0 mS·cm. -1 It is easy to dissociate and form a large number of freely migrating Li + This ensures that the electrolyte possesses excellent ionic conductivity and rapid interfacial ion transport kinetics, resulting in superior pulse discharge performance.

[0059] In some embodiments of this application, the molar ratio of lithium organoborate to lithium sulfonylimide is 0.33 to 3:1. In the electrolyte, when the molar ratio of lithium organoborate to lithium sulfonylimide is less than 0.33, the content of lithium sulfonylimide is too high, accelerating the instability of the positive electrode and vanadium dissolution. Conversely, when the molar ratio is greater than 3, the content of lithium organoborate is too high, leading to a decrease in electrolyte conductivity and consequently affecting the battery's pulse performance. Controlling the molar ratio of lithium organoborate to lithium sulfonylimide is beneficial for improving the battery's pulse capability and maintaining SM (simultaneous pulse response). x V2O y Structural stability, thereby reducing SM x V2O y There is a risk of vanadium leaching. As an example, the molar ratio of organoboronate lithium salt to sulfonylimide lithium salt is 0.33:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, or 3:1.

[0060] In some embodiments of this application, the concentration of lithium organoborate in the electrolyte is 0.5 mol / L to 1.5 mol / L. Further control of the concentration of lithium organoborate, while controlling the molar ratio of lithium organoborate to lithium sulfonylimide, avoids situations where the concentration of lithium organoborate is too low, resulting in insignificant improvement on gas generation, or where the concentration of lithium organoborate is too high, leading to a decrease in electrolyte conductivity and thus affecting the battery's pulse performance. As examples, the concentration of lithium organoborate is 0.5 mol / L, 0.8 mol / L, 1 mol / L, 1.2 mol / L, or 1.5 mol / L.

[0061] In some embodiments of this application, the concentration of lithium sulfonylimide salt in the electrolyte is 0.5 mol / L to 1.5 mol / L. The concentration of lithium sulfonylimide salt is further controlled while maintaining the molar ratio of lithium organoborate salt to lithium sulfonylimide salt to avoid the concentration being too low, which would affect the pulse performance of the battery, or too high, which would accelerate vanadium dissolution. As examples, the concentration of lithium sulfonylimide salt is 0.5 mol / L, 0.8 mol / L, 1.0 mol / L, 1.2 mol / L, or 1.5 mol / L.

[0062] In some embodiments of this application, the aprotic organic solvent includes at least one of carbonate solvents and ether solvents. Carbonate solvents have the advantages of high dielectric constant and good thermal stability, which helps to reduce the risk of gas generation caused by thermal decomposition of the electrolyte; while ether solvents have low viscosity, which can improve the ion migration rate in the electrolyte and is suitable for high-rate discharge. Optionally, the carbonate solvent includes cyclic carbonates. As an example, cyclic carbonates include at least one of propylene carbonate (PC), ethylene carbonate (EC), butyl carbonate (BC), and γ-butyrolactone (GBL). Optionally, the ether solvent includes at least one of linear monoethers and linear diethers. As an example, linear monoethers include at least one of diethyl ether, ethylpropyl ether, ethyl butyl ether, dipropyl ether, dibutyl ether, methyl propyl ether, and methyl butyl ether.

[0063] The following description is based on specific embodiments.

[0064] Example 1 This embodiment provides a battery, as shown in Table 1. The manufacturing process of this battery includes: S1. Electrolyte preparation: In an argon-filled glove box, propylene carbonate (PC) and dimethyl ethylene glycol (DME) were mixed to obtain a mixed solvent. Lithium tetrafluoroborate (LiBF4) and lithium bis(fluorosulfonyl)imide (LiFSi) were added to the mixed solvent and stirred at room temperature for 3 hours to obtain a lithium silver vanadate battery electrolyte. The concentration of lithium tetrafluoroborate in the electrolyte was 1 mol / L and the concentration of lithium bis(fluorosulfonyl)imide was 1 mol / L. S2, Positive electrode preparation: SVO(AgV2O) 5.5 The positive electrode material, conductive agent SP, and binder PVDF are mixed in a mass ratio of 92:4:4 to prepare a high-viscosity slurry with a viscosity of 10000 cp. This slurry is then coated on both sides of carbon-coated aluminum foil to a thickness of 200 μm. The electrode loading is 300 g / m². After drying at 100℃, the mixture is rolled to a compaction density of 1.30 g / cm³. 3 With a porosity of 52%, it is cut into the corresponding size and pressed onto a titanium current collector to obtain a silver vanadate positive electrode sheet. S3. Negative electrode preparation: The lithium strip is cut into the corresponding size and pressed onto the nickel current collector to obtain the negative electrode sheet; S4. Diaphragm: Cut the diaphragm to the corresponding size to obtain the diaphragm; S5. Battery assembly: The SVO positive electrode, the lithium metal negative electrode and the separator are assembled into a battery cell by stacking. The prepared primary lithium silver vanadate battery electrolyte is injected into the battery cell with an injection coefficient of 1.5 g / Ah. After sealing, the lithium silver vanadate battery is obtained.

[0065] Example 2 This embodiment provides a battery, please refer to Table 1. The preparation process of this battery is the same as in Example 1, except that lithium bis(fluorosulfonyl)imide (LiFSi) is replaced with lithium bis(trifluoromethylsulfonyl)imide (LiTFSi).

[0066] Example 3 This embodiment provides a battery, please refer to Table 1. The preparation process of this battery is the same as in Example 1, except that lithium tetrafluoroborate (LiBF4) is replaced with lithium bis(oxalateborate) (LiBOB).

[0067] Example 4 This embodiment provides a battery, please refer to Table 1. The preparation process of this battery is the same as in Example 1, except that the concentration of lithium tetrafluoroborate in the electrolyte is 1.5 mol / L and the concentration of lithium difluorosulfonylimide is 0.5 mol / L.

[0068] Example 5 This embodiment provides a battery, please refer to Table 1. The preparation process of this battery is the same as in Example 1, except that the concentration of lithium tetrafluoroborate in the electrolyte is 1.2 mol / L and the concentration of lithium difluorosulfonylimide is 0.8 mol / L.

[0069] Example 6 This embodiment provides a battery, please refer to Table 1. The preparation process of this battery is the same as in Example 1, except that the concentration of lithium tetrafluoroborate in the electrolyte is 0.8 mol / L and the concentration of lithium difluorosulfonylimide is 1.2 mol / L.

[0070] Example 7 This embodiment provides a battery, please refer to Table 1. The preparation process of this battery is the same as in Example 1, except that the concentration of lithium tetrafluoroborate in the electrolyte is 0.5 mol / L and the concentration of lithium difluorosulfonylimide is 1.5 mol / L.

[0071] Example 8 This embodiment provides a battery, please refer to Table 1. The preparation process of this battery is the same as in Example 1, except that propylene carbonate (PC) is replaced with γ-butyrolactone (GBL).

[0072] Comparative Example 1 This comparative example provides a battery, please refer to Table 1. The preparation process of this battery is the same as in Example 1, except that lithium tetrafluoroborate is omitted and the concentration of lithium difluorosulfonylimide is 2 mol / L.

[0073] Comparative Example 2 This comparative example provides a battery, please refer to Table 1. The preparation process of this battery is the same as in Example 1, except that lithium bis(fluorosulfonyl)imide is omitted and the concentration of lithium tetrafluoroborate is 2 mol / L.

[0074] Comparative Example 3 This comparative example provides a battery, please refer to Table 1. The preparation process of this battery is described in Example 1, the difference being that lithium hexafluorophosphate (LiPF6) is used instead of lithium tetrafluoroborate and lithium difluorosulfonylimide, and the concentration of lithium hexafluorophosphate in the electrolyte is 2 mol / L.

[0075] Table 1

[0076] Performance testing: 1. Conductivity Test: Under constant temperature conditions of 25°C ± 0.5°C, a precision conductivity meter calibrated with a standard potassium chloride solution is used for measurement. The specific steps include injecting the electrolyte to be tested into a clean sample cell, allowing it to stand until the temperature is constant, then completely immersing the instrument electrodes below the liquid surface. After the reading stabilizes, the conductivity value is recorded. The measurement is repeated three times, and the average value is taken as the final result. The conductivity meter is preferably a four-electrode instrument with a constant temperature control unit, and the test frequency is set between 1kHz and 10kHz to eliminate electrode polarization effects.

[0077] 2. Hysteresis Voltage Difference Test: The term "pulse" refers to a short burst of current with an amplitude significantly greater than that of the preceding pulse current. A "pulse sequence" consists of at least two electrical pulses. With or without an open circuit, the current, delivered in a relatively short, continuous manner, rests between the pulses. The range of current pulses is from approximately 15 mA / cm². 2 Up to approximately 50 mA / cm 2 An exemplary pulse sequence is provided, consisting of a 10-second cycle of pulses (20 mA / cm). 2 The sequence consists of four pulses, with a 15-second rest period between each pulse. In each table, P1 represents the battery voltage of the first pulse after the pulse sequence is applied. P4 represents the minimum voltage of the fourth pulse in the sequence. The hysteresis voltage difference U = |P1 - P4|.

[0078] 3. Annual Self-Discharge Rate Test: The lithium silver vanadate battery is placed in the sample chamber of a high-precision isothermal microcalorimeter and subjected to a long-term open-circuit storage test at a constant temperature of 25±0.1°C. The microcalorimeter continuously monitors the heat flow signal generated by the battery due to internal side reactions in real time. This heat flow (unit: watts) directly corresponds to the spontaneous dissipation rate of chemical and electrical energy within the battery. By integrating the total heat generation (unit: joules) during the storage period (e.g., 28 days), combined with the battery's nominal voltage or open-circuit voltage, and using the energy equivalence principle (Q_heat = I_loss * V * t), the average equivalent self-discharge current I_loss during this period can be accurately calculated. Finally, the annual self-discharge rate can be calculated using the formula: Annual self-discharge rate = (I_loss * 365 days * 24 hours) / Battery rated capacity (Ah) × 100%. This method achieves a fundamental and non-invasive quantitative characterization of the self-discharge process by directly measuring the heat of side reactions.

[0079] 4. Vanadium leaching test: The prepared lithium silver vanadate battery was placed in a 60℃ oven for 30 days. After disassembly, the lithium metal was collected and the vanadium content in the lithium was tested by ICP.

[0080] The results of the above tests are recorded in Table 2.

[0081] Table 2

[0082] Results analysis: By combining highly stable organoboronate lithium salts with lithium sulfonamide salts with high ionic conductivity (greater than or equal to 8 mS / cm), the probability of vanadium dissolution and structural collapse due to lattice rearrangement in vanadium-based cathode materials during discharge and harsh environments (high-temperature storage) is reduced. While highly conductive salts can improve lithium-ion transport kinetics and promote rapid lithium-ion insertion into the cathode, excessive amounts (e.g., in Example 7 and Comparative Example 1) result in high self-discharge and V dissolution, negatively impacting long-term battery stability. Organoboronate lithium salts, on the other hand, provide dual protection due to their excellent thermal and chemical stability. However, excessive amounts of organoboronate lithium salts (e.g., in Example 4 and Comparative Example 2) lead to excessively low electrolyte conductivity, severe voltage hysteresis, and poor pulse performance. Furthermore, lithium hexafluorophosphate (Comparative Example 3) exhibits poor structural stability and temperature resistance, resulting in the generation of hydrofluoric acid in the battery after storage and significant self-discharge. Only when the ratio of the two salts is within a reasonable range (Examples 1-3, 5, 6, 8) can they synergistically protect the structural integrity of the cathode material. The improved electrolyte composition reduces the increase in battery internal resistance during battery discharge, thereby enhancing the safety and reliability of batteries that can be implanted in cardiac devices.

[0083] The electrolyte, battery, and electrical device provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An electrolyte, characterized in that, It includes aprotic organic solvents and lithium salts, wherein the lithium salts include lithium organoborate and lithium sulfonylimide with an ionic conductivity greater than or equal to 8 mS / cm.

2. The electrolyte according to claim 1, characterized in that, The organoboronate lithium salt includes at least one of lithium tetrafluoroborate, lithium bis(oxalate)borate, and lithium difluorooxalateborate; and / or, The lithium sulfonylimide salt includes at least one of lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide; and / or, In the electrolyte, the molar ratio of the lithium organoborate salt to the lithium sulfonamide salt is (0.33~3):1; and / or, In the electrolyte, the concentration of the organoboronate lithium salt is 0.5 mol / L to 1.5 mol / L; and / or, The concentration of the lithium sulfonamide salt in the electrolyte is 0.5 mol / L to 1.5 mol / L.

3. The electrolyte according to claim 1 or 2, characterized in that, The aprotic organic solvent includes at least one of carbonate solvents and ether solvents.

4. The electrolyte according to claim 3, characterized in that, The carbonate solvents include cyclic carbonates; and / or, the ether solvents include at least one of linear monoethers and linear diethers.

5. A battery, characterized in that, The battery includes a negative electrode, a positive electrode, and a separator, wherein the separator is disposed between the positive electrode and the negative electrode. The battery also includes an electrolyte as described in any one of claims 1 to 4, wherein the positive electrode comprises a general formula SM. x V2O y The transition metal oxide, wherein SM comprises at least one metal selected from groups IB to VIIB and VIII of the periodic table, wherein x is 0.30 to 2.0 and y is 4.5 to 6.0; the negative electrode comprises lithium.

6. The battery according to claim 5, characterized in that, The transition metal oxides include those with the general formula Ag. x V2O y Silver vanadium oxide; and / or, The transition metal oxide includes Cu. x1 Ag x2 V2O y Transition metal oxides, wherein x1 is 0.10~1.0 and x2 is 0.10~1.

0.

7. The battery according to claim 5 or 6, characterized in that, The positive electrode also includes a composite carbonaceous active material.

8. The battery according to claim 7, characterized in that, The composite carbonaceous active material comprises materials with the chemical formula (CF). z ) n Fluorocarbon materials, where z is 0.1~1.9 and n is the number of monomer units.

9. The battery according to any one of claims 5 to 8, characterized in that, The positive electrode includes a positive current collector and a positive electrode film layer disposed on the positive current collector, the positive electrode film layer including the transition metal oxide, binder and conductive agent.

10. The battery according to any one of claims 5 to 9, characterized in that, The negative electrode contains at least one of lithium and its alloys and intermetallic compounds.

11. The battery according to claim 10, characterized in that, The negative electrode comprises at least one of Li-Si, Li-Al, Li-B, Li-Mg, Li-Si-B alloy and intermetallic compound.

12. The battery according to any one of claims 5 to 11, characterized in that, The negative electrode includes a negative current collector and a negative electrode film layer disposed on the negative current collector, the negative electrode film layer containing the lithium.

13. An electrical appliance, characterized in that, Includes the battery as described in any one of claims 5 to 12.

14. The electrical appliance according to claim 13, characterized in that, The electrical device includes implantable medical devices.

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