Electrochemical apparatus and electronic apparatus

Abstract

The present invention provides an electrochemical apparatus and an electronic apparatus. The electrochemical apparatus comprises a positive electrode containing a positive electrode active material, the positive electrode active material containing the metallic elements Co and Mn, with a mass content of Mn of B% relative to the total mass of the positive electrode active material, and an electrolyte containing a boron-containing lithium salt, with a mass content of the boron-containing lithium salt of C% relative to the total mass of the electrolyte, satisfying 0.05 ≤ C ≤ 1 and 0.01 ≤ C / 10B ≤ 2. The electrochemical apparatus of the present invention can simultaneously achieve high-temperature stability and cycle stability under high voltage and has excellent hot-box performance.

Description

[Technical Field]

[0001] The present invention relates to the field of electrochemical technology, and more specifically to electrochemical apparatus and electronic apparatus. [Background technology]

[0002] Lithium-ion batteries possess characteristics such as high specific energy, high operating voltage, low self-discharge rate, small volume, and light weight, and are widely applied in various fields such as power storage, portable electronic devices, and electric vehicles. As the range of applications for lithium-ion batteries expands, higher demands have been placed on them. For example, there is a growing demand for lithium-ion batteries with higher energy density and longer service life.

[0003] Increasing the operating off voltage of a lithium-ion battery can significantly improve the battery's energy density. However, as the voltage increases, the battery's stability, particularly its high-temperature stability, deteriorates rapidly. Doping the positive electrode can significantly improve its thermal stability. As the doping element increases, the positive electrode material gradually dissolves, significantly affecting the thermal stability of the negative electrode as well. This invention aims to achieve both thermal stability and cycle stability of the positive and negative electrodes by primarily adjusting the positive electrode material and electrolyte. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The object of the present invention is to provide electrochemical and electronic devices that improve the high-temperature cycling performance, room-temperature cycling performance, and hot-box performance of electrochemical devices. The specific technical solution is as follows. [Means for solving the problem]

[0005] In one embodiment, the present invention provides an electrochemical apparatus comprising a positive electrode containing a positive electrode active material, the positive electrode active material containing the metal element Co and the metal element Mn, wherein the mass content of Mn is B% with respect to the total mass of the positive electrode active material, and an electrolyte containing a boron-containing lithium salt, wherein the mass content of the boron-containing lithium salt is C% with respect to the total mass of the electrolyte, satisfying 0.05 ≤ C ≤ 1 and 0.01 ≤ C / 10B ≤ 2.

[0006] The inventors of this invention have found that the introduction of the doping element Mn has a remarkable effect in improving the high-temperature stability of the cathode material at high voltages. While we do not wish to be bound by any theory, this may be because Mn is stable with respect to O, and therefore improves the structural stability of the cathode material. However, as the Mn content increases further, the thermal stability of the anode deteriorates somewhat. However, by introducing a boron-containing lithium salt into the electrolyte, it is possible to achieve both thermal stability of the cathode and anode, and it has also been found that this effect is most evident when C / 10B is within the above range. While we do not wish to be bound by any theory, this may be because the introduction of the boron-containing lithium salt suppresses the dissolution of manganese ions and improves the thermal stability, hydrolysis stability, and oxidation stability of the electrolyte, thereby compensating for the deterioration of the dissolution of the cathode material due to metal element doping. Furthermore, electrolytes containing lithium bis(oxalato)borate (LiBOB) are characterized by their ability to form a stable and effective passivation film in propylene carbonate (PC) solution, without corroding the aluminum foil of the current collector, without attenuation of discharge capacity under high-temperature conditions, and thereby balancing the thermal stability of the positive and negative electrodes.

[0007] In some embodiments, at least one of the following conditions (a) to (b) is met: (a) 0.1 ≤ C ≤ 1, and (b) 0.05 ≤ C / 10B ≤ 1.

[0008] In some embodiments, when the mass content ratio of Co is A% with respect to the total mass of the positive electrode active material, A and B satisfy at least one of the following conditions: 0.05 ≦ B ≦ 0.5, and 6 ≦ A / 20B ≦ 60. Without wishing to be bound by any theory, the Mn element The content When it is within this range, the structural stability of the positive electrode material can be further enhanced, and thus, the thermal stability and high-temperature cycle stability at high voltages of the battery can be improved.

[0009] In some embodiments, the positive electrode active material contains Li α Co 1-x-y Mn x M y O β and M includes one or more of Mg, Al, Ca, Ti, Zr, V, Cr, Fe, Ni, Cu, Zn, Ru, or Sn, and satisfies 0.95 ≦ α ≦ 1.4, 0 < x ≦ 0.4, 0 ≦ y ≦ 0.3, and 1.90 ≦ β ≦ 2.10.

[0010] In some embodiments, the boron-containing lithium salt includes at least one selected from the group consisting of lithium bis(1,1-trifluoromethyl oxalate) borate, lithium bis(1-trifluoromethyl oxalate) borate, lithium difluoro(1,1-trifluoromethyl) oxalate borate, lithium difluoro(oxalato) borate, lithium bis(oxalato) borate, lithium bis(1,1-trifluoromethyl malonate) borate, lithium fluoromalonate difluoro borate, or lithium bis(fluoromalonate) borate.

[0011] The boron-containing lithium salt protects the positive electrode, suppresses the occurrence of related side reactions, and further improves the high-temperature stability of the electrolyte and the cycle stability of the electrochemical device.

[0012] In some embodiments, the electrolyte satisfies at least one of the following conditions (a) to (d): (a) The electrolyte further contains a carboxylic acid ester, and when the mass content of the carboxylic acid ester is X% of the total mass of the electrolyte, the condition 10 ≤ X ≤ 60 is satisfied. (b) The electrolyte further comprises ethylene carbonate and propylene carbonate, and when the mass content of ethylene carbonate is D% and the mass content of propylene carbonate is E% with respect to the total mass of the electrolyte, the following conditions are met: 5 ≤ D + E ≤ 40 and D ≥ E. (c) The electrolyte further comprises at least one selected from the group consisting of 1,3-propanesultone, vinyl sulfate, vinylene carbonate, bicyclic carbonate compound, bicyclic sulfate compound, trinitrile compound, or dinitrile compound, (d) The electrolyte further comprises at least one selected from the group consisting of lithium hexafluoride phosphate, lithium bis(trifluoromethane)sulfonylimide, lithium bis(fluorosulfonyl)imide, or lithium difluorophosphate.

[0013] In some embodiments, the electrolyte satisfies at least one of the following conditions a) to j): a) The mass content of 1,3-propanesultone relative to the total mass of the electrolyte is 0.5% to 5%. b) The mass content of the vinyl sulfate ester relative to the total mass of the electrolyte is 0.1% to 1%. c) The mass content of vinylene carbonate relative to the total mass of the electrolyte is 0.1% to 1%. d) The mass content of the bicyclic carbonate ester compound is 0.1% to 30% of the total mass of the electrolyte. e) The mass content of the bicyclic sulfate ester compound relative to the total mass of the electrolyte is 0.1% to 5%. f) The mass content of the trinitrile compound relative to the total mass of the electrolyte is 0.1% to 10%. j) The mass content of the dinitrile compound relative to the total mass of the electrolyte is 0.1% to 10%.

[0014] In some examples, the carboxylic acid ester includes at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, ethyl propionate, propyl propionate, butyl propionate, pentyl propionate, halogenated methyl acetate, halogenated ethyl acetate, halogenated propyl acetate, halogenated ethyl propionate, halogenated propyl propionate, halogenated butyl propionate, or halogenated pentyl propionate.

[0015] While we do not wish to be constrained by any theory, the introduction of carboxylic acid esters can significantly reduce the viscosity of the electrolyte and improve its electrical conductivity, thereby increasing the transfer rate of lithium ions in the battery, reducing battery polarization, and compensating for the deterioration of kinetics and room-temperature performance caused by doping elements in the positive electrode.

[0016] While we do not wish to be constrained by any theory, by adjusting the amounts of ethylene carbonate and propylene carbonate used, interfacial protection to the negative electrode can be strengthened, the electrolyte consumption rate can be reduced, and the thermal stability and high-temperature cycle stability of lithium-ion batteries can be further enhanced. While we do not wish to be constrained by any theory, by adjusting the above-mentioned electrolyte additives within the range described in this invention, further strengthening of the interfacial film can be achieved, and the thermal stability of lithium-ion batteries can be further improved.

[0017] In some embodiments, the electrochemical apparatus further comprises a separator, the separator including a porous substrate and a porous coating layer provided on at least one surface of the porous substrate, the porous coating layer including inorganic particles and a binder.

[0018] In some embodiments, the separator satisfies at least one of the following conditions (a) to (c): (a) The inorganic particles in the porous coating layer include at least one of magnesium hydroxide, boehmite, or alumina. (b) The binder in the porous coating layer contains polyvinylidene fluoride, (c) When the thickness of the porous coating layer is T μm, 1 ≦ T ≦ 5 is satisfied.

[0019] In other embodiments, the present invention provides an electronic device, and the electronic device includes an electrochemical device according to an embodiment.

[0020] The electrochemical device provided by the present invention can simultaneously achieve both thermal stability and high-temperature cycle stability under high voltage, and has improved hot box performance.

[0021] Other aspects and advantages of the embodiments of the present invention are partially described and shown in the following content, or are explained by the implementation of the embodiments of the present invention.

Embodiments for Carrying Out the Invention

[0022] Hereinafter, in order to make the object, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described with reference to the embodiments. It is clear that the embodiments described below are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments described in the present invention belong to the protection scope of the present invention.

[0023] Hereinafter, the embodiments of the present invention will be described in detail. The embodiments of the present invention should not be construed as limiting the present invention.

[0024] In the present invention, amounts, ratios, and other numerical values may be expressed in a range format. Such a range format is used for convenience and brevity, and should be understood not only flexibly to include the numerical values explicitly listed as the upper and lower limits of the range, but also to include each numerical value or sub-range included in the range as if each numerical value or sub-range was explicitly listed.

[0025] In specific embodiments and claims, a list of items connected by the terms “one of,” “one of,” “a type of,” or other similar terms means any one of the listed items. For example, if items A and B are listed, the phrase “one of A and B” means either A only or B only. In other examples, if items A, B, and C are listed, the phrase “one of A, B, and C” means either A only, B only, or C only. Item A may contain one or more elements. Item B may contain one or more elements. Item C may contain one or more elements.

[0026] In specific embodiments and claims, a list of items connected by the terms “at least one of,” “at least one of,” “at least one kind of,” or other similar terms means any combination of the listed items. For example, if items A and B are listed, the phrase “at least one of A and B” means A only, B only, or A and B. In other examples, if items A, B, and C are listed, the phrase “at least one of A, B, and C” means A only, B only, C only, A and B (excluding C), A and C (excluding B), B and C (excluding A), or all of A, B, and C. Item A may contain one or more elements. Item B may contain one or more elements. Item C may contain one or more elements.

[0027] 1. Electrochemical apparatus In some embodiments, the present invention provides an electrochemical apparatus comprising a positive electrode containing a positive electrode active material, the positive electrode active material containing the metal element Co and the metal element Mn, wherein the mass content of Mn is B% relative to the total mass of the positive electrode active material, and an electrolyte containing a boron-containing lithium salt, wherein the mass content of the boron-containing lithium salt is C% relative to the total mass of the electrolyte, satisfying 0.05 ≤ C ≤ 1 and 0.01 ≤ C / 10B ≤ 2.

[0028] In some embodiments, at least one of the following conditions (a) to (b) is satisfied: (a) 0.1 ≤ C ≤ 1, and (b) 0.05 ≤ C / 10B ≤ 1.

[0029] In some aspects, C is 0.05, 0.08, 0.1, 0.3, 0.5, 0.8, 1, or a range consisting of any two of these numerical values.

[0030] In some aspects, C / 10B is 0.01, 0.03, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.8, 1, 1.5, 1.8, 2.0, or a range consisting of any two of these numerical values.

[0031] In some embodiments, 0.05 ≤ B ≤ 0.5 is satisfied. In some aspects, B is 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.5, or a range consisting of any two of these numerical values.

[0032] In some embodiments, when the mass content ratio of Co is A% with respect to the total mass of the positive electrode active material, 10 ≤ A ≤ 90 is satisfied. In some aspects, A is 10, 20, 30, 40, 50, 55, 58, 60, 62, 65, 70, 80, 90, or a range consisting of any two of these numerical values.

[0033] In some embodiments, 6 ≤ A / 20B ≤ 60 is satisfied. In some embodiments, A / 20B is 6, 8, 10, 12, 15, 18, 20, 25, 28, 30, 32, 35, 40, 45, 50, 55, 60, or a range consisting of any two of these numerical values.

[0034] In some embodiments, the positive electrode active material is Li α Co 1-x-y Mn x M y O βincluding, wherein M includes one or more of Mg, Al, Ca, Ti, Zr, V, Cr, Fe, Ni, Cu, Zn, Ru or Sn, and satisfies 0.95 ≦ α ≦ 1.4, 0 < x ≦ 0.4, 0 ≦ y ≦ 0.3, and 1.90 ≦ β ≦ 2.10.

[0035] In some embodiments, the positive electrode active material includes lithium cobaltate.

[0036] In some embodiments, the boron-containing lithium salt includes at least one selected from the group consisting of lithium bis(1,1-trifluoromethyl oxalate) borate, lithium bis(1-trifluoromethyl oxalate) borate, lithium difluoro(1,1-trifluoromethyl) oxalate borate, lithium difluoro(oxalato) borate, lithium bis(oxalato) borate, lithium bis(1,1-trifluoromethyl malonate) borate, lithium fluoromalonate difluoroborate, or lithium bis(fluoromalonate).

[0037] In some embodiments, the boron-containing lithium salt includes at least one of LiDFOB or LiBOB.

[0038] In some embodiments, the electrolyte satisfies at least one of the following conditions (a) to (d), (a) The electrolyte further includes a carboxylic acid ester. When the mass content ratio of the carboxylic acid ester is X% with respect to the total mass of the electrolyte, 10 ≦ X ≦ 60 is satisfied. (b) The electrolyte further includes ethylene carbonate and propylene carbonate. When the mass content ratio of ethylene carbonate is D% and the mass content ratio of propylene carbonate is E% with respect to the total mass of the electrolyte, 5 ≦ D + E ≦ 40 and D ≧ E are satisfied. (c) The electrolyte further comprises at least one selected from the group consisting of 1,3-propanesultone, vinyl sulfate, vinylene carbonate, bicyclic carbonate compound, bicyclic sulfate compound, trinitrile compound, or dinitrile compound, (d) The electrolyte further comprises at least one selected from the group consisting of lithium hexafluoride phosphate, lithium bis(trifluoromethane)sulfonylimide, lithium bis(fluorosulfonyl)imide, or lithium difluorophosphate.

[0039] In some embodiments, X is a range consisting of 10, 15, 20, 22, 28, 30, 32, 34, 36, 40, 50, 60, or any two of these numbers.

[0040] In some embodiments, the electrolyte satisfies at least one of the following conditions a) to j): a) The mass content of 1,3-propanesultone relative to the total mass of the electrolyte is 0.5% to 5%. b) The mass content of the vinyl sulfate ester relative to the total mass of the electrolyte is 0.1% to 1%. c) The mass content of vinylene carbonate relative to the total mass of the electrolyte is 0.1% to 1%. d) The mass content of the bicyclic carbonate ester compound is 0.1% to 30% of the total mass of the electrolyte. e) The mass content of the bicyclic sulfate ester compound relative to the total mass of the electrolyte is 0.1% to 5%. f) The mass content of the trinitrile compound relative to the total mass of the electrolyte is 0.1% to 10%. j) The mass content of the dinitrile compound relative to the total mass of the electrolyte is 0.1% to 10%.

[0041] In some embodiments, the mass content of 1,3-propanesultone relative to the total mass of the electrolyte is in the range of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any two of these values.

[0042] In some embodiments, the mass content of the vinyl sulfate ester relative to the total mass of the electrolyte is in the range of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or any two of these values.

[0043] In some embodiments, the mass content of vinylene carbonate relative to the total mass of the electrolyte is in the range of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or any two of these values.

[0044] In some embodiments, the mass content of the bicyclic carbonate ester compound relative to the total mass of the electrolyte is in the range of 0.1%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, or any two of these values.

[0045] In some embodiments, the mass content of the bicyclic sulfate ester compound relative to the total mass of the electrolyte is in the range of 0.1%, 0.5%, 1%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any two of these values. In some examples, the carboxylic acid ester includes at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, ethyl propionate, propyl propionate, butyl propionate, pentyl propionate, halogenated methyl acetate, halogenated ethyl acetate, halogenated propyl acetate, halogenated ethyl propionate, halogenated propyl propionate, halogenated butyl propionate, or halogenated pentyl propionate.

[0046] In some examples, the carboxylic acid ester includes ethyl propionate and propyl propionate.

[0047] In some examples, the carboxylic acid ester includes ethyl propionate, propyl propionate, and ethyl acetate.

[0048] In some embodiments, 5 ≤ D + E ≤ 40. In some embodiments, D is in the range of 5, 7, 10, 15, 18, 20, 25, 30, 35, 38, 40, or any two of these numbers.

[0049] In some embodiments, 0 ≤ E ≤ 30. In some embodiments, E is in the range of 0, 5, 8, 10, 15, 18, 20, 25, 30, or any two of these numbers.

[0050] In some embodiments, D > E is satisfied.

[0051] In some embodiments, D+E is a range consisting of 5, 7, 10, 15, 18, 20, 25, 30, 35, 38, 40, or any two of these numbers.

[0052] In some examples, the trinitrile compound includes at least one selected from the group consisting of 1,3,5-pentanetricarbonitrate, 1,2,3-propanetricarbonitrate, 1,3,6-hexanetricarbonitrate, 1,2,6-hexanetricarbonitrate, 1,2,3-tris(2-cyanoethoxy)propane, 1,2,4-tris(2-cyanoethoxy)butane, and 1,2,5-tris(cyanoethoxy)pentane.

[0053] In some examples, the dinitrile compound includes at least one of succinonitrile, glutaronitrile, adiponitrile, 1,5-dicyanopentane, 1,6-dicyanohexane, 1,7-dicyanoheptane, 1,8-dicyanooctane, 1,9-dicyanononane, 1,10-dicyanodecane, 1,12-dicyanododecane, tetramethylsuccinonitrile, 2-methylglutaronitrile, 2,4-dimethylglutaronitrile, and 2,2,4,4-tetramethylglutaronitrile.

[0054] In some embodiments, the mass content of the trinitrile compound is 0 to 10% of the total mass of the electrolyte. In some embodiments, the mass content of the trinitrile compound is in the range of 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any two of these values.

[0055] In some embodiments, the mass content of the dinitrile compound is 0 to 10% of the total mass of the electrolyte. In some embodiments, the mass content of the dinitrile compound is in the range of 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any two of these values.

[0056] In some embodiments, the mass content of lithium hexafluoride phosphate, lithium bis(trifluoromethane)sulfonylimide, lithium bis(fluorosulfonyl)imide, or lithium difluorophosphate is 0.1% to 15%. In some embodiments, the mass content of lithium hexafluoride phosphate, lithium bis(trifluoromethane)sulfonylimide, lithium bis(fluorosulfonyl)imide, or lithium difluorophosphate is in the range of 0.1%, 0.3%, 0.5%, 1%, 1.5%, 1.8%, 2.0%, 2.5%, 3%, 5%, 8%, 10%, 12%, 15%, or any two of these values.

[0057] In some embodiments, the electrolyte further comprises diethyl carbonate (DEC). In some embodiments, the mass content of the diethyl carbonate relative to the total mass of the electrolyte is 20% to 70%. In some embodiments, the mass content of the diethyl carbonate relative to the total mass of the electrolyte is in the range of 10%, 15%, 18%, 20%, 25%, 30%, 35%, 38%, 40%, or any two of these values.

[0058] In some embodiments, the positive electrode further comprises a conductive agent. In some embodiments, the conductive agent comprises at least one selected from the group consisting of carbon nanotubes, carbon fibers, acetylene black, graphene, Ketjenblack, and carbon black.

[0059] In some embodiments, the positive electrode further comprises a binder. In some embodiments, the positive electrode active material layer further comprises a binder. In some embodiments, the binder comprises at least one selected from the group consisting of polyvinylidene fluoride, carboxymethylcellulose, styrene-butadiene rubber, polyvinyl alcohol, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, poly(1,1-difluoroethylene), polyethylene, polypropylene, acrylic acid (esterified) styrene-butadiene rubber, epoxy resin, and nylon.

[0060] In some embodiments, the current collector includes at least one of copper foil and aluminum foil.

[0061] In some embodiments, the positive electrode can be prepared by known preparation methods in the art. For example, the positive electrode can be obtained by preparing an active material composition by mixing a positive electrode active material, a conductive agent, and an adhesive in a solvent, and then applying the active material composition to a current collector. In some embodiments, the solvent includes, but is not limited to, N-methylpyrrolidone.

[0062] In some embodiments, the electrochemical apparatus includes any apparatus for initiating an electrochemical reaction.

[0063] In some embodiments, the electrochemical apparatus is a lithium secondary battery.

[0064] In some embodiments, the lithium secondary battery includes, but is not limited to, a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery, or an all-solid-state secondary lithium battery.

[0065] <Negative electrode> In some embodiments, the materials, configuration, and manufacturing methods of the negative electrode used in the electrochemical apparatus according to the present invention may include any techniques disclosed in the prior art. In some embodiments, the negative electrode is the negative electrode described in U.S. Patent Application US9812739B, the entire text of which is incorporated into the present invention by reference.

[0066] In some embodiments, the negative electrode comprises a current collector and a negative electrode active material layer located on the current collector. In some embodiments, the negative electrode active material layer comprises a negative electrode active material. In some embodiments, the negative electrode active material is lithium metal, structured lithium metal, structured lithium metal, natural graphite, artificial graphite, mesocarbon microbeads (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composite, silicon-oxygen material (e.g., SiO, SiO2), Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO2, lithium TiO2-Li4Ti5O having a spinel structure 12This includes, but is not limited to, Li-Al alloys or any combination thereof.

[0067] In some examples, the negative electrode active material layer includes an adhesive. In some examples, the adhesive includes, but is not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, poly(1,1-difluoroethylene), polyethylene, polypropylene, styrene-butadiene rubber, acrylic acid (esterified) styrene-butadiene rubber, epoxy resin, or nylon.

[0068] In some embodiments, the negative electrode active material layer includes a conductive material. In some embodiments, the conductive material includes, but is not limited to, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, metal powder, metal fiber, copper, nickel, aluminum, silver, or polyphenylene derivatives.

[0069] In some embodiments, the current collector includes, but is not limited to, copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, or a polymer substrate coated with a conductive metal.

[0070] In some embodiments, the negative electrode can be obtained by preparing an active material composition by mixing an active material, a conductive agent, and an adhesive in a solvent, and then applying the active material composition to a current collector.

[0071] In some examples, the solvent may include, but is not limited to, deionized water and N-methylpyrrolidone.

[0072] In some embodiments, the negative electrode in an all-solid-state secondary lithium battery is a metallic lithium foil.

[0073] <Separator> In some embodiments, the electrochemical apparatus further comprises a separator located between the positive electrode and the negative electrode, the separator comprising a porous substrate and a porous coating layer provided on at least one surface of the porous substrate, the porous coating layer comprising inorganic particles and a binder.

[0074] In some embodiments, a porous coating layer is placed on one surface of the porous substrate. In some embodiments, a porous coating layer is placed on both surfaces of the porous substrate.

[0075] In some embodiments, the separator satisfies at least one of the following conditions (a) to (c): (a) The inorganic particles in the porous coating layer include at least one of magnesium hydroxide, boehmite, or alumina. (b) The binder in the porous coating layer comprises polyvinylidene fluoride, (c) When the thickness of the porous coating layer is T μm, the condition 1 ≤ T ≤ 5 is satisfied.

[0076] In some embodiments, T is a range consisting of 1, 2, 3, 4, 5, or any two of these numbers.

[0077] In some embodiments, the material and shape of the separator used in the electrochemical apparatus of the present invention are not particularly limited and can be any technology disclosed in the prior art.

[0078] In some embodiments, the porous substrate can be selected from at least one or more of the following: a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite membrane.

[0079] In some embodiments, the mass content of the fluorine-containing binder is calculated to be between 10% and 70% based on the total mass of inorganic particles and fluorine-containing binder in the porous coating layer. In some embodiments, the mass content of the fluorine-containing binder in the porous coating layer is in the range of 10%, 20%, 30%, 40%, 50%, 60%, 70%, or any two of these values.

[0080] In some embodiments, the mass content of inorganic particles is calculated to be 30-90% based on the total mass of inorganic particles and fluorine-containing binder in the porous coating layer. In some embodiments, the mass content of inorganic particles in the porous coating layer is in the range of 30%, 40%, 50%, 60%, 70%, 80%, 90%, or any two of these values, relative to the total mass of inorganic particles and fluorine-containing binder. The porous coating layer can improve the heat resistance, oxidation resistance, and wettability of the separator and strengthen the adhesion between the separator and the electrode piece.

[0081] In some examples, the binder is one or more selected from the group consisting of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and hexafluoropropylene, polytetrafluoroethylene, and polyhexafluoropropylene.

[0082] <Electrolyte> In some embodiments, the electrolyte used in the electrolyte of the embodiment of the present invention may be an electrolyte known in the prior art, such as inorganic lithium salts such as LiClO4, LiPF6, LiBF4, LiSbF6, LiSO3F, LiN(FSO2)2, for example LiCF3SO3, LiN(FSO2)(CF3SO2), LiN(CF3SO2)2, LiN(C2F5SO2)2, cyclic 1,3-hexafluoropropanedisulfonimidolithium, cyclic 1,2-tetrafluoroethanedisulfonimidolithium, LiN(CF3SO2)(C4F9SO2), LiC(CF3SO2) 3. This includes, but is not limited to, fluorine-containing organolithium salts such as LiPF4(CF3)2, LiPF4(C2F5)2, LiPF4(CF3SO2)2, LiPF4(C2F5SO2)2, LiBF2(CF3)2, LiBF2(C2F5)2, LiBF2(CF3SO2)2, and LiBF2(C2F5SO2)2, as well as lithium salts containing dicarboxylic acid complexes such as lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium tris(oxalato)phosphate, lithium difluorobis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate. The electrolyte may be used individually or two or more simultaneously. For example, in some examples, the electrolyte includes a combination of LiPF6 and LiBF4. In some examples, the electrolyte includes a combination of an inorganic lithium salt such as LiPF6 or LiBF4 and a fluorine-containing organic lithium salt such as LiCF3SO3, LiN(CF3SO2)2, or LiN(C2F5SO2)2. In some examples, the electrolyte concentration is in the range of 0.8 to 3 mol / L, for example, in the range of 0.8 to 2.5 mol / L, 0.8 to 2 mol / L, 1 to 2 mol / L, 0.5 to 1.5 mol / L, 0.8 to 1.3 mol / L, 0.5 to 1.2 mol / L, or for example, 1 mol / L, 1.15 mol / L, 1.2 mol / L, 1.5 mol / L, 2 mol / L, or 2.5 mol / L.

[0083] The preparation process for electrochemical devices is well known to those skilled in the art, and the present invention is not particularly limited in this respect. For example, a lithium-ion battery is manufactured by stacking a positive electrode and a negative electrode with a separator in between, winding and folding them as needed, then placing them in a case, injecting an electrolyte into the case, and sealing it. In addition, if necessary, an overcurrent prevention element, lead plates, etc., may be placed in the case to prevent pressure rise and overcharging / discharging inside the lithium-ion battery.

[0084] 2.Electronic equipment The electronic device of the present invention can be any device that uses the electrochemical apparatus according to the embodiment of the present invention.

[0085] In some embodiments, the electronic devices include, but are not limited to, notebook computers, pen-input computers, mobile computers, e-book readers, mobile phones, portable facsimile machines, portable photocopiers, portable printers, stereo headphones, video recorders, LCD televisions, portable cleaners, portable CD players, MiniDisc players, transceivers, electronic organizers, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric assist bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, strobes, cameras, large household storage batteries, or lithium-ion capacitors.

[0086] The preparation of lithium-ion batteries will be described below, using lithium-ion batteries as an example and referring to specific embodiments. Those skilled in the art should understand that the preparation method described in this invention is merely an example, and any other suitable preparation method falls within the scope of this invention.

[0087] [Examples] Embodiments of the present invention will be described in more detail below with reference to examples and comparative examples. Various tests and evaluations will be carried out according to the methods described below. Unless otherwise specified, "parts" and "%" are based on mass.

[0088] 1. Measurement Method and Equipment (1) Measurement of the content of metallic elements Co and Mn in the positive electrode active material The active material from the positive electrode piece, which has been washed with DMC (dimethyl carbonate), is taken using a doctor blade and dissolved in a mixed solvent (for example, 10 ml of aqua regia (a 1:1 mixture of nitric acid and hydrochloric acid) and 2 ml of HF were used for 0.4 g of positive electrode active material), the volume was adjusted to 100 mL, and the metal elements such as Co and Mn in the solution were analyzed using an ICP analyzer. mass content The measurement is taken, and the unit is "%".

[0089] (2) Measurement of high-temperature cycle performance of lithium-ion batteries Under conditions of 45°C, a lithium-ion battery was charged with a constant current at 0.7C (rate) up to 4.5V, then charged with a constant voltage until the current dropped to 0.05C, and finally discharged with a constant current at 1C up to 3.0V. This constituted one charge-discharge cycle, and this was the first cycle. The discharge capacity of the lithium-ion battery after the first cycle was recorded. Charge-discharge cycles were performed on the lithium-ion battery according to the above method, and the discharge capacity of each cycle was recorded. The cycle was terminated when the discharge capacity of the lithium-ion battery decreased to 80% of the discharge capacity of the first cycle, and the number of charge-discharge cycles was recorded.

[0090] (3) Measurement of the room temperature cycle performance of lithium-ion batteries Under conditions of 25°C, a lithium-ion battery was charged with a constant current at 0.7C (rate) up to 4.5V, then charged with a constant voltage until the current dropped to 0.05C, and finally discharged with a constant current at 1C up to 3.0V. This constituted one charge-discharge cycle, and this was the first cycle. The discharge capacity of the lithium-ion battery after the first cycle was recorded. Charge-discharge cycles were performed on the lithium-ion battery according to the above method, and the discharge capacity of each cycle was recorded. The cycle was terminated when the discharge capacity of the lithium-ion battery decreased to 80% of the discharge capacity of the first cycle, and the number of charge-discharge cycles was recorded.

[0091] (4) Hotbox safety testing of lithium-ion batteries Before thermal shock, the cells were fully charged. Their appearance was inspected and photographed before and after the test. A temperature-sensing wire was attached to the center of the outer surface of the cell. The sample was placed vertically in a box and heated to the desired test temperature (130 / 135) ±2°C at a heating rate of 2±2°C, and held for 60 minutes. For measurement frequency, voltage and internal resistance were measured using a 1KHz standard, after pretreatment and after the test. The test pass criterion was that there was no fire or explosion. Here, "5 / 10 Pass" means that out of 10 batteries tested in each example, 5 passed.

[0092] 2. Preparation of lithium-ion batteries [Examples 1-9 and Comparative Examples 1-3] (1) Preparation of modified cathode active material

[0093] Commercial lithium cobalt oxide (LiCoO2) and trimanganese tetroxide (Mn3O4) were mixed in a high-speed mixer at 300 r / min for 20 minutes. The mixture was then placed in an air furnace and heated to 820°C at a rate of 5°C / min, held for 24 hours, and after natural cooling, removed and passed through a 300-mesh sieve to obtain a modified cathode active material (i.e., modified LiCoO2). In the modified cathode active material, the metallic elements Mn and Co mass content The total is as shown in Table 1.

[0094] (2) Preparation of positive electrode piece Modified LiCoO2, carbon nanotubes (CNTs) as a conductive agent, and polyvinylidene fluoride as a binder were mixed in a mass ratio of 95:2:3. N-methylpyrrolidone (NMP) was added as a solvent, and the mixture was stirred with a vacuum stirrer until a homogeneous positive electrode slurry with a solid content of 75 wt% was obtained. The positive electrode slurry was uniformly coated onto a 12 μm thick aluminum foil positive electrode current collector, dried at 85°C, and cold-pressed to obtain a positive electrode piece with a positive electrode active material layer thickness of 100 μm. The same procedure was repeated on the other surface of the same positive electrode piece to obtain a positive electrode piece with positive electrode active material layers coated on both sides. The positive electrode piece was cut to a size of 74 mm × 867 mm, tabs were welded on, and it was set aside.

[0095] (3) Preparation of the negative electrode piece Artificial graphite, styrene-butadiene rubber (SBR), and carboxymethylcellulose (CMC), which are the negative electrode active materials, were mixed in a mass ratio of 95:2:3. Deionized water was added as a solvent to prepare a slurry with a solid content of 70 wt%, and the mixture was uniformly stirred. The slurry was uniformly applied to one surface of an 8 μm thick copper foil, dried at 110°C, and after cold pressing, a negative electrode piece was obtained with a negative electrode active material layer thickness of 150 μm, coated on one side. The above procedure was then repeated on the other surface of the same negative electrode piece to obtain a negative electrode piece with negative electrode active material layers coated on both sides. The negative electrode pieces were cut to a size of 74 mm × 867 mm, tabs were welded on, and they were set aside. The degree of defect Id / Ig of the negative electrode pieces was 0.17.

[0096] (4) Preparation of electrolyte In an argon gas-atmosphered glove box with a moisture content of less than 10 ppm, ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were uniformly mixed in a mass ratio of 20:20:60 to form the base solvent. Lithium hexafluoride phosphate (LiPF6) and a boron-containing lithium salt were added to this base solvent and uniformly stirred to form the electrolyte. Based on the total mass of the electrolyte, the mass content of LiPF6 was calculated to be 12.5%, and the specific mass content of the boron-containing lithium salt is shown in Table 1. mass content The total is 100%.

[0097] In Table 1, LiDFOB represents lithium difluoro(oxalato)borate, and LiBOB represents lithium bis(oxalato)borate.

[0098] (5) Preparation of separators A porous polymerized polyethylene (PE) thin film with a thickness of 12 μm is used as a separator, and a porous coating consisting of Al2O3 and PVDF is applied to both surfaces of the base film, with a thickness of 3 μm. The mass content of Al2O3 in the porous coating is 70%, and the mass content of PVDF in the porous coating is 30%.

[0099] (6) Preparation of lithium-ion batteries An electrode assembly was obtained by stacking the positive electrode piece, separator, and negative electrode piece in order, winding them up, and having the separator interposed between the positive electrode piece and the negative electrode piece to act as an isolation. The electrode assembly was placed in an aluminum plastic film that served as the outer casing, and after removing moisture at 80°C, the prepared electrolyte was injected. A lithium-ion battery was then obtained through processes such as vacuum packaging, standing, formation, and shaping.

[0100] [Examples 10-14] <Preparation of Electrolyte> In an argon gas-atmosphered glove box with a moisture content of less than 10 ppm, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and carboxylic acid esters were uniformly mixed in a mass ratio of 20:20:(60-X):X to form the base solvent. LiPF6 and boron-containing lithium salt were added to this base solvent and uniformly stirred to form the electrolyte. Based on the total mass of the electrolyte, the mass content of the boron-containing lithium salt was calculated to be 0.5%, and the mass content of LiPF6 was calculated to be 12.5%. The types of carboxylic acid esters, their mass content, related preparation parameters, and changes in performance are shown in Table 2. mass content This is calculated based on the total mass of the base solvent. Here, the amount of each substance in the electrolyte mass content The total is 100%.

[0101] The preparation of the electrolyte in this example differs from that in Example 6, but all other aspects are the same as in Example 6. [Examples 15-20] <Preparation of Electrolyte>

[0102] In an argon gas-atmosphered glove box with a moisture content of less than 10 ppm, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and / or polypropylene (PP) were uniformly mixed to form the base solvent. LiPF6 and a boron-containing lithium salt were added to the base solvent and uniformly stirred to form the electrolyte. Based on the total mass of the electrolyte, the mass content of the boron-containing lithium salt was calculated to be 0.5%, and the mass content of LiPF6 was 12.5%. The mass content of other substances, related preparation parameters, and changes in performance are shown in Table 3. mass content This is calculated based on the total mass of the base solvent. Here, the amount of each substance in the electrolyte mass content The total is 100%.

[0103] The preparation of the electrolyte in this example differs from that in Example 6, but all other aspects are the same as in Example 6.

[0104] [Examples 21-23] <Preparation of Electrolyte> In an argon gas-atmosphered glove box with a moisture content of less than 10 ppm, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and / or polypropylene (PP) were uniformly mixed to form the base solvent. LiPF6, lithium bis(oxalato)borate (LiBOB), and 1,3,6-hexanetricarbonitric acid were added to the base solvent and uniformly stirred to form the electrolyte. Based on the total mass of the electrolyte, the mass content of LiPF6 was calculated to be 12.5%, and the mass content of the boron-containing lithium salt was 0.5%. The specific mass content and performance of the other substances are shown in Table 4. The EC, PC, and PP content in Table 4 were calculated based on the total mass of the base solvent. The mass content of 1,3,6-hexanetricarbonitric acid shown in Table 4 was calculated based on the total mass of the electrolyte. mass content The total is 100%.

[0105] The preparation of the electrolyte in this example differs from that in Example 6, but all other aspects are the same as in Example 6. [Examples 24-27]

[0106] In an argon gas-atmosphered glove box with a moisture content of less than 10 ppm, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and / or polypropylene (PP) were uniformly mixed to form the base solvent. LiPF6, lithium bis(oxalato)borate (LiBOB), and / or 1,3,6-hexanetricarbonitride were added to the base solvent and uniformly stirred to form the electrolyte. Based on the total mass of the electrolyte, the mass content of LiPF6 was calculated to be 12.5%, and the mass content of the boron-containing lithium salt was 0.5%. The specific mass content and performance of the other substances are shown in the table. 5 As shown in Table 5, EC, PC and PP mass content This is calculated based on the total mass of the base solvent. The mass content of 1,3,6-hexanetricarbonitride shown in Table 5 is calculated based on the total mass of the electrolyte. Here, the mass content of each substance in the electrolyte is calculated based on the total mass of the electrolyte. mass content The total is 100%. <Preparation of the separator>

[0107] A porous polymerized polyethylene (PE) thin film with a thickness of 12 μm was used as a separator, and a porous coating consisting of Al2O3 and PVDF was applied to both surfaces of the base film. The thickness of the porous coating is as shown in Table 5. The mass content of Al2O3 in the porous coating is 70%, and the mass content of PVDF in the porous coating is 30%.

[0108] The preparation of the separator and electrolyte in this example differs from that in Example 6, but all other aspects are the same as in Example 6.

[0109] [Table 1]

[0110] As can be seen from Examples 1 to 9 and Comparative Examples 1 to 3 in Table 1, adjusting C / 10B within the range of the present invention significantly improves the hot box pass rate of lithium-ion batteries at 130°C and 135°C. While we do not wish to be constrained by any theory, it is thought that this may be because Mn has stability relative to O, and consequently, improves the structural stability of the positive electrode material. However, as the content of Mn element increases further, the thermal stability of the negative electrode deteriorates slightly, but by introducing a boron-containing lithium salt into the electrolyte, it is possible to achieve both positive and negative electrode thermal stability, and it was also found that this effect is most clear when C / 10B is within the above range. While we do not wish to be constrained by any theory, it is thought that this may be because the introduction of the boron-containing lithium salt suppresses the dissolution of manganese ions, and improves the thermal stability, hydrolysis stability, and oxidation stability of the electrolyte, compensating for the deterioration of the dissolution of the positive electrode material due to metal element doping. Furthermore, electrolytes containing lithium bis(oxalato)borate (LiBOB) are characterized by their ability to form a stable and effective passivation film in propylene carbonate (PC) solution, without corroding the aluminum foil of the current collector, without attenuation of discharge capacity under high-temperature conditions, and thereby balancing the thermal stability of the positive and negative electrodes.

[0111] [Table 2]

[0112] As can be seen from Examples 10 to 14 in Table 2, introducing an appropriate amount of carboxylic acid ester into the electrolyte has a certain effect in improving both the high-temperature cycle stability and the room-temperature cycle stability of lithium-ion batteries. Although we do not wish to be constrained by any theory, the introduction of carboxylic acid ester can significantly reduce the viscosity of the electrolyte and improve its electrical conductivity, which in turn can improve the transfer rate of lithium ions in the battery, reduce the polarization of the battery, and compensate for the deterioration of kinetics and room-temperature performance caused by doping elements in the positive electrode.

[0113] [Table 3]

[0114] As can be seen from Examples 15 to 20 in Table 3, when D and E are within the scope of the present invention, lithium-ion batteries can obtain superior cycle performance. Although we do not wish to be constrained by any theory, by adjusting the amounts of ethylene carbonate and propylene carbonate used, interfacial protection to the negative electrode can be strengthened, the electrolyte consumption rate can be reduced, and the thermal stability and high-temperature cycle stability of lithium-ion batteries can be further enhanced. Although we do not wish to be constrained by any theory, by adjusting the above electrolyte additives within the scope described in the present invention, further strengthening of the interfacial film can be achieved, and the thermal stability of lithium-ion batteries can be further improved.

[0115] [Table 4]

[0116] As can be seen from Examples 21 to 23 in Table 4, the cycle stability of lithium-ion batteries can be further improved by adding a nitrile-based additive (e.g., 1,3,6-hexanetricarbonitrate) to the electrolyte. Although not bound by any theory, the cyano group in the nitrile-based additive has strong coordinating ability and can bind to active sites on the electrode surface (e.g., high-potency tetravalent cobalt ions), exerting a masking effect on these active ions on the positive electrode surface, thereby reducing the decomposition of the electrolyte by the electrode and decreasing side reactions, thus improving cycle performance.

[0117] [Table 5]

[0118] As can be seen from Examples 24-27 in Table 5, when the thickness of the porous coating layer of the separator is 1-5 μm, the cycle performance of the lithium-ion battery at high temperature and room temperature can be further improved.

[0119] References throughout this specification to “several embodiments,” “part of an embodiment,” “one embodiment,” “another example,” “example,” “a specific example,” or “part of an example” mean that at least one embodiment or example in the present invention has the specific features, structure, or property described in that embodiment or example. Thus, phrases such as “in some embodiments,” “in one embodiment,” “in one embodiment,” “in another example,” “in one example,” “a specific example,” or “example” appear throughout this specification, but they do not necessarily refer to the same embodiment or example in the present invention. Furthermore, specific features, structures, materials, or properties disclosed herein may be implemented in any suitable form in combination in one or more examples or illustrations.

[0120] While exemplary embodiments have been shown and described, it will be obvious to those skilled in the art that these embodiments cannot be interpreted as limiting the present invention, and that these embodiments can be modified, substituted, and altered without departing from the spirit, principles, and scope of the present invention.

Claims

1. A positive electrode comprising a positive electrode active material, wherein the positive electrode active material contains the metallic elements Co and Mn, and the mass content of Mn is B% relative to the total mass of the positive electrode active material, An electrolyte containing a boron-containing lithium salt, wherein the mass content of the boron-containing lithium salt is C% relative to the total mass of the electrolyte, Equipped with, An electrochemical apparatus characterized by satisfying 0.05 ≤ C ≤ 1 and 0.01 ≤ C / 10B ≤ 2.

2. Satisfying at least one of the following conditions (a) to (b), (a) 0.1 ≤ C ≤ 1, and (b) 0.05≦C / 10B≦1 The electrochemical apparatus according to claim 1, characterized in that

3. When the mass content of Co is A% relative to the total mass of the positive electrode active material, A and B satisfy at least one of the following conditions: 0.05 ≤ B ≤ 0.5, and 6 ≤ A / 20B ≤ 60, The electrochemical apparatus according to claim 1, characterized in that

4. The positive electrode active material is Li α Co １－ｘ－ｙ Mn ｘ M ｙ O β Includes, The aforementioned M includes one or more of the following: Mg, Al, Ca, Ti, Zr, V, Cr, Fe, Ni, Cu, Zn, Ru, or Sn. The electrochemical apparatus according to claim 1, characterized in that it satisfies 0.95 ≤ α ≤ 1.4, 0 < x ≤ 0.4, 0 ≤ y ≤ 0.3, and 1.90 ≤ β ≤ 2.

10.

5. The electrochemical apparatus according to claim 1, characterized in that the boron-containing lithium salt comprises at least one selected from the group consisting of lithium bis(1,1-trifluoromethyloxalate)borate, lithium bis(1-trifluoromethyloxalate)borate, lithium difluoro(1,1-trifluoromethyl)oxalate borate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium bis(1,1-trifluoromethylmalonic acid)borate, lithium fluoromalonate difluoroborate, or lithium bis(fluoromalonic acid)borate.

6. The electrolyte satisfies at least one of the following conditions (a) to (d): (a) The electrolyte further contains a carboxylic acid ester, and when the mass content of the carboxylic acid ester is X% with respect to the total mass of the electrolyte, the condition 10 ≤ X ≤ 60 is satisfied. (b) The electrolyte further contains ethylene carbonate and propylene carbonate, and the mass content of ethylene carbonate is D% and the mass content of propylene carbonate is E% with respect to the total mass of the electrolyte, satisfying 5 ≤ D + E ≤ 40 and D ≥ E. (c) The electrolyte further comprises at least one selected from the group consisting of 1,3-propanesultone, vinyl sulfate, vinylene carbonate, bicyclic carbonate compound, bicyclic sulfate compound, trinitrile compound, or dinitrile compound, (d) The electrolyte further comprises at least one selected from the group consisting of lithium hexafluoride phosphate, lithium bis(trifluoromethane)sulfonylimide, lithium bis(fluorosulfonyl)imide, or lithium difluorophosphate. The electrochemical apparatus according to claim 1, characterized in that

7. The electrochemical apparatus according to claim 6, characterized in that the carboxylic acid ester comprises at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, ethyl propionate, propyl propionate, butyl propionate, pentyl propionate, halogenated methyl acetate, halogenated ethyl acetate, halogenated propyl acetate, halogenated ethyl propionate, halogenated propyl propionate, halogenated butyl propionate, or halogenated pentyl propionate.

8. The electrolyte satisfies at least one of the following conditions a) to j): a) The mass content of 1,3-propanesultone relative to the total mass of the electrolyte is 0.5% to 5%. b) The mass content of the vinyl sulfate ester relative to the total mass of the electrolyte is 0.1% to 1%. c) The mass content of vinylene carbonate relative to the total mass of the electrolyte is 0.1% to 1%. d) The mass content of the bicyclic carbonate compound is 0.1% to 30% of the total mass of the electrolyte. e) The mass content of the bicyclic sulfate ester compound is 0.1% to 5% of the total mass of the electrolyte. f) The mass content of the trinitrile compound relative to the total mass of the electrolyte is 0.1% to 10%. j) The mass content of the dinitrile compound is 0.1% to 10% relative to the total mass of the electrolyte. The electrochemical apparatus according to claim 5, characterized in that

9. It is further equipped with a separator, The separator includes a porous substrate and a porous coating layer provided on at least one surface of the porous substrate. The electrochemical apparatus according to claim 1, characterized in that the porous coating layer comprises inorganic particles and a binder.

10. The separator satisfies at least one of the following conditions (a) to (c): (a) The inorganic particles in the porous coating layer include at least one of magnesium hydroxide, boehmite, or alumina. (b) The binder in the porous coating layer comprises polyvinylidene fluoride, (c) When the thickness of the porous coating layer is T μm, the following conditions must be met: 1 ≤ T ≤ 5 The electrochemical apparatus according to claim 9, characterized in that

11. An electronic device characterized by comprising an electrochemical apparatus as described in any one of claims 1 to 10.

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