Semi-solid-state battery

Abstract

In order to solve the problem that an electrolyte of an existing semi-solid-state battery is not matched, the semi-solid-state battery comprises a positive electrode, a negative electrode, a diaphragm and a non-aqueous electrolyte, the diaphragm is located between the positive electrode and the negative electrode, at least one surface of the diaphragm is provided with a solid electrolyte coating, and the non-aqueous electrolyte is arranged on the surface of the diaphragm. The non-aqueous electrolyte comprises a non-aqueous organic solvent, a lithium salt and an additive, and the additive comprises fluoroethylene carbonate and a boron-containing lithium salt additive; the semi-solid battery satisfies the following conditions: 0.3 < = S * V / 100 * (L + 1 / F) < = 12.35, 1 < = S < = 6, 0.3 < = F < = 4, 0.05 < = L < = 1.5, and 70 < = V < = 95. The semi-solid battery provided by the invention can have relatively long cycle life and relatively good high-temperature stability under the condition of relatively high working voltage.

Description

Technical Field

[0001] The invention belongs to the technical field of energy storage electronic components, and in particular relates to a semi-solid-state battery. Background Art

[0002] Lithium-ion batteries have the advantages of high operating voltage, wide operating temperature range, high energy density, high output power, no memory effect and long cycle life. They are not only widely used in 3C digital products such as mobile phones and laptops, but also have a broad application market in new energy vehicles and large-scale energy storage. "Range anxiety" is a topic that cannot be avoided in the field of electric vehicles, and it also continuously promotes the continuous improvement of battery energy density. High voltage is one of the mainstream technical routes in the future. The chemical system of positive and negative electrode materials determines the upper limit of the energy density of the battery cell. The operating voltage upper limit of the currently widely used nickel-cobalt-manganese ternary and LFP systems is ≤4.5V. Overcharging will be accompanied by irreversible structural damage and rapid capacity decay. Compared with conventional liquid electrolyte components, solid electrolyte materials have higher safety and wider voltage windows, and are expected to solve the problem of incompatibility between high-voltage positive electrode materials such as lithium-rich manganese-based and spinel nickel-manganese oxide and existing electrolytes.

[0003] During the charge and discharge process of the battery, a part of the lithium is often unable to be embedded in the negative electrode, but is deposited on the surface of the negative electrode, forming lithium dendrites. The growth of lithium dendrites pierces the diaphragm and causes an internal short circuit. After that, the SEI film, diaphragm, electrolyte, and positive electrode material successively decompose and release heat and oxygen, which promotes further accumulation of heat and eventually reaches the combustion conditions of the electrolyte. The battery suffers thermal runaway and eventually catches fire and explodes.

[0004] Semi-solid batteries are an intermediate solution for the transition from liquid batteries to all-solid batteries. Solid electrolytes are coated on both sides of the positive electrode material, negative electrode material or diaphragm while retaining the traditional liquid electrolyte to achieve solid-liquid mixing. Compared with liquid batteries, semi-solid batteries introduce solid electrolytes, which can improve energy density and safety on the basis of the existing system; compared with all-solid-state batteries, semi-solid batteries retain some electrolytes, improving conductivity and interface contact issues. Since the liquid battery structure is basically retained, semi-solid batteries are highly compatible with existing production lines and do not bring greater challenges to the production process of battery companies. Overall, it is the industry's current better choice.

[0005] The introduction of solid electrolyte materials into the existing battery system poses a compatibility test to the design of the electrolyte. When conventional electrolytes are used in semi-solid batteries, they are not compatible due to the significant changes in the properties of the contact interface. The mutual influence of chemical / electrochemical reactions may aggravate the degradation of battery performance. In order to match the battery performance under semi-solid technology, it is necessary to provide a high-voltage compatible electrolyte and lithium-ion battery for semi-solid technology. Summary of the invention

[0006] In view of the problem of electrolyte incompatibility in existing semi-solid batteries, the present invention provides a semi-solid battery.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows: The present invention provides a semi-solid-state battery, comprising a positive electrode, a negative electrode, a separator and a non-aqueous electrolyte, wherein the separator is located between the positive electrode and the negative electrode, at least one surface of the separator is provided with a solid electrolyte coating, the non-aqueous electrolyte comprises a non-aqueous organic solvent, a lithium salt and an additive, and the additive comprises fluoroethylene carbonate and a boron-containing lithium salt additive; The semi-solid-state battery meets the following conditions: 0.3≤S*V / 100*(L+1 / F)≤12.35, and 1≤S≤6, 0.3≤F≤4, 0.05≤L≤1.5, 70≤V≤95; Wherein, S is the thickness of the solid electrolyte coating, in μm; F is the mass percentage of fluoroethylene carbonate in the non-aqueous electrolyte, unit is %; L is the mass percentage of the boron-containing lithium salt additive in the non-aqueous electrolyte, in %; V is the capacity ratio in the high-voltage range, which is the percentage of the charging capacity of the semi-solid-state battery in the 4.5V~5V range to the charging capacity in the total range of 3.4V~5V, in %.

[0008] Optionally, the semi-solid-state battery meets the following conditions: 0.35≤S*V / 100*(L+1 / F)≤4.75.

[0009] Optionally, the thickness S of the solid electrolyte coating is 1.5-4.5 μm.

[0010] Optionally, the mass percentage F of fluoroethylene carbonate in the non-aqueous electrolyte is 0.5%~3%.

[0011] Optionally, the mass percentage L of the boron-containing lithium salt additive in the non-aqueous electrolyte is 0.1%~1%.

[0012] Optionally, the high-voltage interval capacity proportion V is 80%~90%.

[0013] Optionally, the solid electrolyte coating includes a solid electrolyte, and the solid electrolyte includes at least one of lithium aluminum titanium phosphate, lithium titanium phosphate, lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide, lithium tetrathiophosphate, lithium germanium phosphosulfur sulfide, and lithium phosphosulfur chloride.

[0014] Optionally, the boron-containing lithium salt additive includes at least one of LiODFB and LiBOB.

[0015] Optionally, the additive further includes at least one of a cyclic sulfate compound, a sultone compound, a cyclic carbonate compound, a phosphate compound, a borate compound and a nitrile compound; The cyclic sulfate ester compound includes at least one of vinyl sulfate, 1,3,2-dioxathiacyclohexane-2,2-dioxide, and methyl vinyl sulfate; and / or The sultone compound includes at least one of 1,3-propane sultone, 1,4-butane sultone and 1,3-propene sultone; and / or The cyclic carbonate compound includes at least one of vinylene carbonate, vinyl ethylene carbonate, methylene carbonate or the compound shown in structural formula 1: Structural formula 1 In the structural formula 1, R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Each is independently selected from a hydrogen atom, a halogen atom, a C1-C5 group; and / or The phosphate compound includes at least one of tris(trimethylsilyl)phosphate, tris(triethylsilyl)phosphate or the compound shown in structural formula 2: Structural formula 2 In the structural formula 2, R 31 , R 32 , R 33 Each is independently selected from a C1-C5 saturated hydrocarbon group, a C1-C5 unsaturated hydrocarbon group, a C1-C5 halogenated hydrocarbon group, -Si(C m H 2m+1 ) 3 , m is a natural number from 1 to 3, and R 31 , R 32 , R 33 At least one of them is an unsaturated hydrocarbon group; and / or The borate compound includes at least one of tris(trimethylsilyl)borate and tris(triethylsilyl)borate; and / or The nitrile compound includes at least one of succinonitrile, glutaronitrile, hexanetrinitrile, adiponitrile, pimelonitrile, suberonitrile, azelaic acid dinitrile and sebacononitrile.

[0016] Optionally, the positive electrode includes a positive electrode material layer containing a positive electrode active material, and the positive electrode active material includes at least one of the compounds represented by Formula (A) or Formula (B).

[0017] LiNi x M 2-x A y O r B p Formula (A) nLi 2 MnO 3 ·(1 - n)LiMO 2 Formula (B) In Formula (A), 0 ≤ x ≤ 1, 1 ≤ 2 - x ≤ 2, 0 ≤ y ≤ 0.05, 1 ≤ r ≤ 4, 0 ≤ p ≤ 4, r + p ≤ 4, M includes at least one of Mn and Al, A includes at least one of Zr, Zn, Cu, Cr, Fe, V, Ti, Sr, Sb, Sn, Y, W, Al, and Nb, and B includes at least one of F, Cl, and Br; In Formula (B), 0 < n < 1, and M includes at least one of Ni, Co, Mn, and Al.

[0018] According to the semi-solid battery provided by the present invention, a solid electrolyte coating is provided on the diaphragm, and fluoroethylene carbonate and boron-containing lithium salt additives are added to the non-aqueous electrolyte as additives. The inventors have found through a large number of blending studies that, for the purpose of improving the cycle performance and high-temperature storage performance of the semi-solid battery, the high-voltage range capacity proportion V of the semi-solid battery, the addition amount F of fluoroethylene carbonate and the addition amount L of the boron-containing lithium salt additive in the non-aqueous electrolyte, and the thickness S of the solid electrolyte coating have obvious interrelated influences. When the high voltage range capacity proportion V of the semi-solid battery is increased, the addition amount F of fluoroethylene carbonate and the addition amount L of the boron-containing lithium salt additive in the non-aqueous electrolyte are increased, and the thickness S of the solid electrolyte coating is increased. When the capacity ratio V in the high-voltage range, the addition amount F of fluoroethylene carbonate and the addition amount L of boron-containing lithium salt additive in the non-aqueous electrolyte, and the thickness S of the solid electrolyte coating meet the conditions of 0.3≤S*V / 100*(L+1 / F)≤12.35, and 1≤S≤6, 0.3≤F≤4, 0.05≤L≤1.5, 70≤V≤95, the obtained semi-solid-state battery can have a longer cycle life and better high-temperature stability under the condition of having a higher working voltage. It is speculated that this is because the capacity ratio V in the high-voltage range of the semi-solid-state battery not only determines The energy density of the semi-solid-state battery is determined, and the decomposition and gas production of the non-aqueous electrolyte on the positive electrode surface is greatly affected. Fluorinated ethylene carbonate and boron-containing lithium salt additives can form an interface film on the positive and negative electrode surfaces during the battery formation stage. The formed interface film is in direct contact with the solid electrolyte coating. By controlling the relative proportion of fluoroethylene carbonate and boron-containing lithium salt additives, the composition of the interface film derived from different additives can be controlled, thereby adjusting the compatibility of the interface film with the solid electrolyte coating. The high-voltage range capacity proportion V of the semi-solid-state battery determines the required thickness of the solid electrolyte coating and the thickness of the interface film. The thickness selection of the solid electrolyte coating correspondingly affects the thickness requirement of the interface film, thereby affecting the appropriate addition content of fluoroethylene carbonate and boron-containing lithium salt additives. When the high-voltage range capacity proportion V of the semi-solid-state battery, the addition amount F of fluoroethylene carbonate in the non-aqueous electrolyte, the addition amount L of the boron-containing lithium salt additive, and the thickness S of the solid electrolyte coating are in a synergistic state, it is beneficial to ensure the adaptability of the formed interface film to the solid electrolyte coating and the working voltage, and obtain a semi-solid-state battery with excellent electrochemical performance. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] An embodiment of the present invention provides a semi-solid-state battery, comprising a positive electrode, a negative electrode, a separator and a non-aqueous electrolyte, wherein the separator is located between the positive electrode and the negative electrode, and at least one surface of the separator is provided with a solid electrolyte coating, and the non-aqueous electrolyte comprises a non-aqueous organic solvent, a lithium salt and an additive, wherein the additive comprises fluoroethylene carbonate and a boron-containing lithium salt additive; The semi-solid-state battery meets the following conditions: 0.3≤S*V / 100*(L+1 / F)≤12.35, and 1≤S≤6, 0.3≤F≤4, 0.05≤L≤1.5, 70≤V≤95; Wherein, S is the thickness of the solid electrolyte coating, in μm; F is the mass percentage of fluoroethylene carbonate in the non-aqueous electrolyte, unit is %; L is the mass percentage of the boron-containing lithium salt additive in the non-aqueous electrolyte, in %; V is the capacity ratio in the high-voltage range, which is the percentage of the charging capacity of the semi-solid-state battery in the 4.5V~5V range to the charging capacity in the total range of 3.4V~5V, in %.

[0021] Based on the purpose of improving the cycle performance and high-temperature storage performance of semi-solid batteries, the inventors found through a large number of deployment studies that the high-voltage range capacity proportion V of the semi-solid battery, the addition amount F of fluoroethylene carbonate in the non-aqueous electrolyte and the addition amount L of the boron-containing lithium salt additive, and the thickness S of the solid electrolyte coating have obvious interrelated influences. When the high-voltage range capacity proportion V of the semi-solid battery, the addition amount F of fluoroethylene carbonate in the non-aqueous electrolyte and the addition amount L of the boron-containing lithium salt additive, and the thickness S of the solid electrolyte coating meet the conditions of 0.3≤S*V / 100*(L+1 / F)≤12.35, and 1≤S≤6, 0.3≤F≤4, 0.05≤L≤1.5, 70≤V≤95, the obtained semi-solid battery can have a longer cycle life and better high-temperature stability under the condition of having a higher energy density. It is speculated that this is because the high-voltage range capacity proportion V of the semi-solid battery not only determines the energy density of the semi-solid battery, but also affects the decomposition products of the non-aqueous electrolyte on the surface of the positive electrode. The influence of gas is relatively large, while fluoroethylene carbonate and boron-containing lithium salt additives can form an interface film on the surface of the positive and negative electrodes during the battery formation stage, and the formed interface film is in direct contact with the solid electrolyte coating. By controlling the relative proportion of fluoroethylene carbonate and boron-containing lithium salt additives, the composition of the interface film derived from different additives can be controlled, thereby adjusting the compatibility of the interface film with the solid electrolyte coating. The high-voltage range capacity proportion V of the semi-solid battery determines the required thickness of the solid electrolyte coating and the thickness of the interface film. The thickness selection of the solid electrolyte coating correspondingly affects the thickness requirement of the interface film, thereby affecting the appropriate addition content of fluoroethylene carbonate and boron-containing lithium salt additives. When the high-voltage range capacity proportion V of the semi-solid battery, the addition amount F of fluoroethylene carbonate in the non-aqueous electrolyte, the addition amount L of the boron-containing lithium salt additive, and the thickness S of the solid electrolyte coating are in a synergistic state, it is beneficial to ensure the adaptability of the formed interface film to the solid electrolyte coating and the working voltage, and obtain a semi-solid battery with excellent electrochemical performance.

[0022] In some embodiments, the total interval charging capacity of the semi-solid-state battery refers to the charging capacity of the semi-solid-state battery in the range of 3.4V to 5V.

[0023] In a preferred embodiment, the semi-solid-state battery satisfies the following conditions: 0.35≤S*V / 100*(L+1 / F)≤4.75.

[0024] When the high-voltage range capacity proportion V of the semi-solid-state battery, the addition amount F of fluoroethylene carbonate in the non-aqueous electrolyte, the addition amount L of the boron-containing lithium salt additive, and the thickness S of the solid electrolyte coating further meet the above conditions, it is beneficial to further improve the cycle performance and high-temperature storage performance of the semi-solid-state battery.

[0025] In some embodiments, the solid electrolyte coating is only disposed on a single side surface of the diaphragm facing the positive electrode, or the solid electrolyte coating is only disposed on a single side surface of the diaphragm facing the negative electrode, or the solid electrolyte coating is disposed on both side surfaces of the diaphragm.

[0026] In a specific embodiment, the thickness S of the solid electrolyte coating can be 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2.0 μm, 2.3 μm, 2.6 μm, 2.9 μm, 3.0 μm, 3.3 μm, 3.6 μm, 3.9 μm, 4.0 μm, 4.3 μm, 4.6 μm, 4.9 μm, 5.0 μm, 5.3 μm, 5.6 μm, 5.9 μm, 6.0 μm or a range between any two of the above values.

[0027] In a preferred embodiment, the thickness S of the solid electrolyte coating is 1.5-4.5 μm.

[0028] Setting a solid electrolyte coating on the surface of the diaphragm can conduct lithium ions and insulate electrons, which can inhibit the transfer of electrons through the diaphragm to a certain extent, while not significantly increasing the impedance of the diaphragm. After the solid electrolyte contacts lithium, gradual lithiation will occur, and the lithiation product can react with the lithium dendrites that pierce the diaphragm to inhibit the continued growth of lithium dendrites; in addition, the solid electrolyte coating diaphragm has a certain hardness, which can block the penetration of lithium dendrites to a certain extent. The thickness of the solid electrolyte coating should be controlled accordingly. When the thickness is too large, it will cause the internal resistance of the diaphragm to increase, so that the transmission process of lithium ions in the diaphragm is hindered and the battery performance is reduced. If the coating is too thin, the solid electrolyte coating will absorb too little lithium. When lithium dendrites grow in large quantities, it cannot effectively inhibit the growth of dendrites, resulting in puncture of the diaphragm.

[0029] In a specific embodiment, the mass percentage F of fluoroethylene carbonate in the non-aqueous electrolyte can be 0.3%, 0.5%, 0.6%, 1%, 1.2%, 1.5%, 1.8%, 2.0%, 2.3%, 2.6%, 2.9%, 3.0%, 3.3%, 3.6%, 3.9%, 4.0% or the range between any two of the above values.

[0030] In a preferred embodiment, the mass percentage F of fluoroethylene carbonate in the non-aqueous electrolyte is 0.5% to 3%.

[0031] Fluorinated ethylene carbonate has both the film-forming properties of cyclic carbonates and the high-voltage compatibility of fluorinated solvents, and has a wide electrochemical stability window, so it can match high-voltage positive electrode materials. The interface film formed based on fluoroethylene carbonate contains a large amount of LiF. Since LiF has a large band gap, low Li +Diffusion energy barrier and high surface energy, so the interface film can effectively block the penetration of electrons and promote Li + The rapid diffusion of lithium can be achieved by reducing the side reactions between the electrode interface and the non-aqueous electrolyte, which is beneficial to promoting the uniform deposition of lithium. However, the film formation process of fluoroethylene carbonate is accompanied by the production of a large amount of carbon dioxide. The gas barrier between the pole pieces will cause the lithium insertion path to be blocked and the battery safety to decrease. Therefore, the gas production of non-aqueous electrolyte containing fluoroethylene carbonate in high-voltage system is a key obstacle to application development. After the semi-solid electrolyte coating is introduced at the diaphragm level, the interfacial reaction is suppressed based on the consideration of improving the stability of the system, and the corresponding content requirement of fluoroethylene carbonate changes. If the content of fluoroethylene carbonate in the non-aqueous electrolyte is too low, it will be difficult to improve the semi-solid battery; if the content of fluoroethylene carbonate in the non-aqueous electrolyte is too high, the thickness of the interface film will be too large, affecting Li + The diffusion of gases increases the battery impedance and the risk of gas production.

[0032] In a specific embodiment, the mass percentage L of the boron-containing lithium salt additive in the non-aqueous electrolyte is 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5% or the range between any two of the above values.

[0033] In a preferred embodiment, the mass percentage L of the boron-containing lithium salt additive in the non-aqueous electrolyte is 0.1%~1%.

[0034] When a solid electrolyte coating is set on the surface of the diaphragm, the interface between the diaphragm and the positive and negative electrodes will be hardened. If the stability and strength of the interface film cannot adapt to the increase in the strength of the diaphragm, the interface film may be broken due to cross stress, thereby causing more violent side reactions and accumulation of by-products. Lithium salt additives are the key additive type to increase the inorganic components of the interface film, and the inorganic components correspond to the increase in the strength of the interface film. Boron-containing lithium salt additives decompose and open the ring on the positive electrode side, and then polymerize to form a small amount of inorganic salt protective film, which inhibits the solvent decomposition of non-aqueous electrolytes under high pressure and destroys the electrode structure. At the same time, the B atoms exposed on the outside due to the opening of the ring can attract hexafluorophosphate and fluoride ions to combine with it, inhibiting the decomposition of non-aqueous electrolytes. In addition, boron-containing lithium salt additives can consume trace hydrogen fluoride (HF) in the system, and a small amount of lithium difluorooxalate borate and lithium tetrafluoroborate generated during the cycle process are beneficial to the overall performance of the battery. As the thickness of the solid electrolyte coating increases, the content of boron-containing lithium salt additives is increased within a limited range, which is conducive to stress matching balance and ensures stable electrochemical performance.

[0035] In a specific embodiment, the high-voltage interval capacity proportion V can be 70%, 71%, 74%, 76%, 78%, 79%, 80%, 81.5%, 82%, 84%, 85%, 86%, 87%, 89%, 90%, 92%, 94%, 95% or a range between any two of the above values.

[0036] In a preferred embodiment, the high-voltage interval capacity proportion V is 80% to 90%.

[0037] The higher the high-voltage range capacity proportion V of the semi-solid-state battery, the higher its operating voltage and the greater the energy density of the battery. However, as the high-voltage range capacity proportion V increases, the requirements for the non-aqueous electrolyte are also higher, and the non-aqueous electrolyte is more likely to decompose under high operating voltage. Therefore, according to the selection of the high-voltage range capacity proportion V of the semi-solid-state battery, it is necessary to control the thickness of the solid electrolyte coating and the interface film to achieve an adaptation effect to ensure the normal use of the semi-solid-state battery. When the high-voltage range capacity proportion V of the semi-solid-state battery is within the above range, on the one hand, it has a higher energy density, and on the other hand, it can achieve better adaptability of the solid electrolyte coating and the interface film through the regulation of the condition 0.3≤S*V / 100*(L+1 / F)≤12.35, and has better cycle performance and high temperature performance.

[0038] The test method of the high-voltage interval capacity ratio V is: First, charge the battery at 0.1C constant current and constant voltage to the upper limit voltage (if the upper limit voltage is less than 5V, use the upper limit voltage), then discharge it at 0.1C constant current to 3.4V, repeat this charge and discharge twice to activate the battery within the total voltage range; Then, charge the battery at 0.5C constant current and constant voltage to the upper limit voltage, and then discharge it to 3.4V at 0.5C constant current, and record the charging capacity during the charging and discharging process, where the charging capacity from the start of charging to charging to the upper limit voltage is the charging capacity V1 of the total interval, and the charging capacity from charging to 4.5V to charging to the upper limit voltage is the charging capacity V2 of the interval from 4.5V to the upper limit voltage. The high-voltage interval capacity proportion V=V2 / V1*100%.

[0039] In some embodiments, the solid electrolyte coating includes a solid electrolyte, and the solid electrolyte includes at least one of lithium aluminum titanium phosphate, lithium titanium phosphate, lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide, lithium tetrathiophosphate, lithium germanium phosphosulfur sulfide, and lithium phosphosulfur chloride.

[0040] In some embodiments, the mass percentage of the solid electrolyte in the solid electrolyte coating is greater than or equal to 80%, and more preferably greater than or equal to 90%.

[0041] In some embodiments, the solid electrolyte coating further includes a binder.

[0042] In some embodiments, the binder includes polyvinylidene fluoride, copolymers of vinylidene fluoride, polytetrafluoroethylene, copolymers of vinylidene fluoride-hexafluoropropylene, copolymers of tetrafluoroethylene-hexafluoropropylene, copolymers of tetrafluoroethylene-perfluoroalkyl vinyl ether, copolymers of ethylene-tetrafluoroethylene, copolymers of vinylidene fluoride-tetrafluoroethylene, copolymers of vinylidene fluoride-trifluoroethylene, copolymers of vinylidene fluoride-trichloroethylene, copolymers of vinylidene fluoride-fluoroethylene, copolymers of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimide, thermoplastic resins such as polyethylene and polypropylene; acrylic resin; and at least one of styrene butadiene rubber.

[0043] In some embodiments, the separator includes one or more of polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), polyimide (PI), polyether sulfone (PES), polycarbonate (PC), polyphenylene sulfide (PPS), polyethylene oxide (PEO), and polymethyl methacrylate (PMMA).

[0044] In some embodiments, the boron-containing lithium salt additive includes at least one of LiODFB (lithium difluorooxalatoborate) and LiBOB (lithium bis(oxalatoborate)).

[0045] In some embodiments, the additive further comprises at least one of a cyclic sulfate compound, a sultone compound, a cyclic carbonate compound, a phosphate compound, a borate compound, and a nitrile compound.

[0046] In some embodiments, the cyclic sulfate ester compound includes at least one of vinyl sulfate, 1,3,2-dioxathiacyclohexane-2,2-dioxide, and methyl vinyl sulfate.

[0047] In some embodiments, the sultone compound includes at least one of 1,3-propane sultone, 1,4-butane sultone, and 1,3-propene sultone.

[0048] In some embodiments, the cyclic carbonate compound includes at least one of vinylene carbonate, vinyl ethylene carbonate, methylene carbonate, or a compound shown in Structural Formula 1: Structural formula 1 In the structural formula 1, R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Each is independently selected from a hydrogen atom, a halogen atom, and a C1-C5 group.

[0049] In some embodiments, the phosphate compound includes at least one of tris(trimethylsilyl)phosphate, tris(triethylsilyl)phosphate or the compound shown in formula 2: Structural formula 2 In the structural formula 2, R 31 , R 32 , R 33 Each is independently selected from a C1-C5 saturated hydrocarbon group, a C1-C5 unsaturated hydrocarbon group, a C1-C5 halogenated hydrocarbon group, -Si(C m H 2m+1 ) 3 , m is a natural number from 1 to 3, and R 31 , R 32 , R 33 At least one of them is an unsaturated hydrocarbon group.

[0050] In a preferred embodiment, the phosphate compound shown in the structural formula 2 may be at least one of tripropargyl phosphate, dipropargyl methyl phosphate, dipropargyl ethyl phosphate, dipropargyl propyl phosphate, dipropargyl trifluoromethyl phosphate, dipropargyl-2,2,2-trifluoroethyl phosphate, dipropargyl-3,3,3-trifluoropropyl phosphate, dipropargyl hexafluoroisopropyl phosphate, triallyl phosphate, diallyl methyl phosphate, diallyl ethyl phosphate, diallyl propyl phosphate, diallyl trifluoromethyl phosphate, diallyl-2,2,2-trifluoroethyl phosphate, diallyl-3,3,3-trifluoropropyl phosphate, and diallyl hexafluoroisopropyl phosphate.

[0051] In some embodiments, the borate compound includes at least one of tris(trimethylsilyl)borate and tris(triethylsilyl)borate; and / or In some embodiments, the nitrile compound includes at least one of succinonitrile, glutaronitrile, hexanetrinitrile, adiponitrile, pimelonitrile, suberonitrile, azelaic acid dinitrile, and sebacononitrile.

[0052] In other embodiments, the additives may also include other additives that can improve battery performance: for example, additives that enhance battery safety performance, such as flame retardant additives such as fluorophosphates and cyclophosphazenes, or overcharge prevention additives such as tert-amylbenzene and tert-butylbenzene.

[0053] It should be noted that, unless otherwise specified, in general, the content of any one of the optional substances in the additives in the non-aqueous electrolyte is less than 10%, preferably, the content is 0.01-5%, and more preferably, the content is 0.1%~2%. Specifically, the content of any one of the optional substances in the additives can be 0.01%, 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 7.8%, 8%, 8.5%, 9%, 9.5%, 10%.

[0054] In some embodiments, based on the total mass of the non-aqueous electrolyte being 100%, the mass content of the non-aqueous organic solvent is 65% to 90%.

[0055] Specifically, based on the total mass of the non-aqueous electrolyte as 100%, the mass content of the non-aqueous organic solvent can be 65%, 68%, 71%, 74%, 76%, 78%, 79%, 80%, 81.5%, 82%, 84%, 85%, 86%, 87%, 89%, or 90%.

[0056] In some embodiments, the non-aqueous organic solvent includes at least one of an ether solvent, a nitrile solvent, a carbonate solvent, a carboxylate solvent, and a sulfone solvent.

[0057] In some embodiments, the ether solvent includes a cyclic ether or a chain ether, preferably a chain ether with 3 to 10 carbon atoms and a cyclic ether with 3 to 6 carbon atoms. The cyclic ether may be, but is not limited to, 1,3-dioxolane (DOL), 1,4-dioxane (DX), crown ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH 3 -THF), 2-trifluoromethyltetrahydrofuran (2-CF 3-THF); the chain ether may specifically be, but is not limited to, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether. Since the chain ether has a high solvation ability with lithium ions and can improve ion dissociation, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane, which have low viscosity and can impart high ion conductivity, are particularly preferred. The ether compound can be used alone or in any combination and ratio. There is no special restriction on the amount of ether compound added, which is arbitrary within the range that does not significantly damage the effect of the high-density lithium-ion battery of the present invention. In the non-aqueous solvent volume ratio of 100%, the volume ratio is usually 1% or more, preferably 2% or more, and more preferably 3% or more. In addition, the volume ratio is usually 30% or less, preferably 25% or less, and more preferably 20% or less.

[0058] In some embodiments, the nitrile solvent may specifically be but is not limited to at least one of acetonitrile, glutaronitrile, and malononitrile.

[0059] In some embodiments, the carbonate solvent includes a cyclic carbonate or a chain carbonate, and the cyclic carbonate may be, but is not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), and butylene carbonate (BC); the chain carbonate may be, but is not limited to, at least one of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and dipropyl carbonate (DPC). The content of the cyclic carbonate is not particularly limited, and is arbitrary within the range that does not significantly damage the effect of the lithium ion battery of the present invention, but when one is used alone, the lower limit of its content is usually 3% or more by volume, preferably 5% or more by volume, relative to the total amount of solvent in the non-aqueous electrolyte. By setting this range, the conductivity can be reduced due to the reduction in the dielectric constant of the non-aqueous electrolyte, and it is easy to make the large current discharge characteristics, stability relative to the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery reach a good range. In addition, the upper limit is usually 90% or less by volume, preferably 85% or less by volume, and more preferably 80% or less by volume. By setting this scope, the oxidation / reduction tolerance of nonaqueous electrolyte can be improved, thus contribute to the stability during high temperature storage. The content of linear carbonate is not particularly limited, and relative to the total amount of solvent of nonaqueous electrolyte, it is usually more than 15% by volume, preferably more than 20% by volume, and more preferably more than 25% by volume. In addition, usually the volume ratio is less than 90%, preferably less than 85% by volume, and more preferably less than 80% by volume. By making the content of linear carbonate in the above-mentioned scope, it is easy to make the viscosity of nonaqueous electrolyte reach appropriate range, suppress the reduction of ionic conductivity, and then contribute to make the output characteristics of nonaqueous electrolyte battery reach good scope. When two or more linear carbonates are used in combination, the total amount of linear carbonate is made to meet the above-mentioned scope.

[0060] In certain embodiments, it is also possible to preferably use chain carbonates with fluorine atoms (hereinafter referred to as "fluorinated chain carbonates"). The number of fluorine atoms possessed by the fluorinated chain carbonate is not particularly limited as long as it is more than 1, but is generally less than 6, preferably less than 4. When the fluorinated chain carbonate has a plurality of fluorine atoms, these fluorine atoms can be bonded to the same carbon or to different carbons. As the fluorinated chain carbonate, fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, fluorinated diethyl carbonate derivatives, etc. can be listed.

[0061] The carboxylate solvent includes cyclic carboxylate and / or chain carbonate. Examples of cyclic carboxylate include at least one of γ-butyrolactone, γ-valerolactone, and δ-valerolactone. Examples of chain carbonate include at least one of methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), and butyl propionate.

[0062] In some embodiments, the sulfone solvent includes a cyclic sulfone and a chain sulfone. Preferably, in the case of a cyclic sulfone, it is usually a compound with 3 to 6 carbon atoms, preferably 3 to 5 carbon atoms, and in the case of a chain sulfone, it is usually a compound with 2 to 6 carbon atoms, preferably 2 to 5 carbon atoms. There is no special restriction on the amount of sulfone solvent added, and it is arbitrary within the range that does not significantly damage the effect of the lithium ion battery of the present invention. Relative to the total amount of solvent of the non-aqueous electrolyte, the volume ratio is usually 0.3% or more, preferably 0.5% or more, and more preferably 1% or more. In addition, the volume ratio is usually 40% or less, preferably 35% or less, and more preferably 30% or less. In the case of using two or more sulfone solvents in combination, the total amount of sulfone solvents can be made to meet the above range. When the amount of sulfone solvent added is within the above range, a non-aqueous electrolyte with excellent high temperature storage stability tends to be obtained.

[0063] In some embodiments, the lithium salt comprises LiPF 6 、LiPO 2 F 2 , LiBF 4 、LiSbF 6 、LiAsF 6 、LiN(SO 2 F) 2 、LiN(SO 2 CF 3 ) 2 、LiN(SO 2 C 2 F 5 ) 2 、LiC(SO 2 CF 3 ) 3 、LiClO 4 、LiAlCl 4 、LiCF 3 SO 3 、LiSO 3 F. at least one of lithium trioxalatephosphate, a lithium lower aliphatic carboxylate having 4 or less carbon atoms, or lithium tetraphenylborate.

[0064] In some embodiments, in the non-aqueous electrolyte, the concentration of the lithium salt is 0.1 mol / L to 4 mol / L. In preferred embodiments, in the non-aqueous electrolyte, the concentration of the lithium salt is 0.5 mol / L to 2.5 mol / L. Specifically, in the non-aqueous electrolyte, the concentration of the lithium salt can be 0.5 mol / L, 0.55 mol / L, 0.6 mol / L, 0.65 mol / L, 0.7 mol / L, 0.8 mol / L, 0.85 mol / L, 0.9 mol / L, 0.95 mol / L, 1.0 mol / L, 1.1 mol / L, 1.15 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.45 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2.0 mol / L, 2.1 mol / L, 2.2 mol / L, 2.3 mol / L, 2.4 mol / L or 2.5 mol / L.

[0065] In some embodiments, the positive electrode includes a positive electrode material layer containing a positive electrode active material, and the positive electrode active material includes at least one of the compounds represented by formula (A) or formula (B).

[0066] LiNi x M 2-x A y O r B p Formula (A) nLi 2 MnO 3 ·(1 - n)LiMO 2 Formula (B) In formula (A), 0 ≤ x ≤ 1, 1 ≤ 2 - x ≤ 2, 0 ≤ y ≤ 0.05, 1 ≤ r ≤ 4, 0 ≤ p ≤ 4, r + p ≤ 4, M includes at least one of Mn and Al, A includes at least one of Zr, Zn, Cu, Cr, Fe, V, Ti, Sr, Sb, Sn, Y, W, Al, and Nb, and B includes at least one of F, Cl, and Br; In formula (B), 0 < n < 1, and M includes at least one of Ni, Co, Mn, and Al.

[0067] In some embodiments, the positive electrode material layer further includes a positive electrode binder and a positive electrode conductive agent, and the positive electrode active material, the positive electrode binder, and the positive electrode conductive agent are blended to obtain the positive electrode material layer.

[0068] The positive electrode binder includes polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-hexafluoropropylene, a copolymer of tetrafluoroethylene-perfluoroalkyl vinyl ether, a copolymer of ethylene-tetrafluoroethylene, a copolymer of vinylidene fluoride-tetrafluoroethylene, a copolymer of vinylidene fluoride-trifluoroethylene, a copolymer of vinylidene fluoride-trichloroethylene, a copolymer of vinylidene fluoride-fluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimide, a thermoplastic resin such as polyethylene and polypropylene; an acrylic resin; and at least one of styrene butadiene rubber.

[0069] The positive electrode conductive agent includes at least one of conductive carbon black, conductive carbon balls, conductive graphite, conductive carbon fibers, carbon nanotubes, graphene or reduced graphene oxide.

[0070] In some embodiments, the positive electrode current collector includes a metal material that can conduct electrons. Preferably, the positive electrode current collector includes at least one of Al, Ni, tin, copper, and stainless steel. In a more preferred embodiment, the positive electrode current collector is selected from aluminum foil.

[0071] In some embodiments, the negative electrode includes a negative electrode material layer, the negative electrode material layer includes a negative electrode active material, and the negative electrode active material includes at least one of a carbon-based negative electrode, a silicon-based negative electrode, a tin-based negative electrode, and a lithium negative electrode. The carbon-based negative electrode may include graphite, hard carbon, soft carbon, graphene, mesophase carbon microspheres, etc.; the silicon-based negative electrode may include silicon materials, silicon oxides, silicon-carbon composite materials, and silicon alloy materials, etc.; the tin-based negative electrode may include tin, tin carbon, tin oxygen, and tin metal compounds; the lithium negative electrode may include metallic lithium or a lithium alloy. The lithium alloy may specifically be at least one of a lithium silicon alloy, a lithium sodium alloy, a lithium potassium alloy, a lithium aluminum alloy, a lithium tin alloy, and a lithium indium alloy.

[0072] In a more preferred embodiment, the negative electrode active material includes at least one of graphite, hard carbon, soft carbon, graphene, and silicon-carbon composite materials.

[0073] In some embodiments, the silicon material is one or more of silicon nanoparticles, silicon nanowires, silicon nanotubes, silicon thin films, 3D porous silicon, and hollow porous silicon.

[0074] In some embodiments, the negative electrode further comprises a negative electrode current collector, and the negative electrode material layer covers the surface of the negative electrode current collector. The negative electrode current collector comprises a metal material that can conduct electrons, preferably, the negative electrode current collector comprises at least one of Al, Ni, tin, copper, and stainless steel, and in a more preferred embodiment, the negative electrode current collector is selected from copper foil.

[0075] In some embodiments, the negative electrode material layer further includes a negative electrode binder and a negative electrode conductive agent, and the negative electrode active material, the negative electrode binder and the negative electrode conductive agent are blended to obtain the negative electrode material layer.

[0076] The negative electrode binder includes polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-hexafluoropropylene, a copolymer of tetrafluoroethylene-perfluoroalkyl vinyl ether, a copolymer of ethylene-tetrafluoroethylene, a copolymer of vinylidene fluoride-tetrafluoroethylene, a copolymer of vinylidene fluoride-trifluoroethylene, a copolymer of vinylidene fluoride-trichloroethylene, a copolymer of vinylidene fluoride-fluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimide, a thermoplastic resin such as polyethylene and polypropylene; an acrylic resin; and at least one of styrene butadiene rubber.

[0077] The negative electrode conductive agent includes at least one of conductive carbon black, conductive carbon balls, conductive graphite, conductive carbon fibers, carbon nanotubes, graphene or reduced graphene oxide.

[0078] The present invention is further described below by way of examples.

[0079] Table 1 In Table 1, LATP is lithium aluminum titanium phosphate, LLZO is lithium lanthanum zirconium oxide, and LLZTO is lithium lanthanum zirconium tantalum oxide.

[0080] Example 1 This example is used to illustrate the preparation method of the semi-solid battery disclosed in the present invention, which includes the following steps: The positive electrode preparation steps are as follows: high voltage lithium nickel manganese oxide active material LNMO, conductive carbon black and binder polyvinylidene fluoride are mixed in a mass ratio of 94.5:3.0:2.5, dispersed in N-methyl-2-pyrrolidone to obtain positive electrode slurry, the positive electrode slurry is evenly coated on both sides of aluminum foil, and after drying, rolling and vacuum drying, an aluminum lead wire is welded with an ultrasonic welder to obtain a positive electrode plate, and the thickness of the plate is between 120-150 μm; The negative electrode preparation steps are as follows: graphite material, conductive carbon black, binder styrene-butadiene rubber and carboxymethyl cellulose are mixed in a mass ratio of 95.2:1.0:2.4:1.4, dispersed in deionized water to obtain a negative electrode slurry, the negative electrode slurry is coated on both sides of a copper foil, and after drying, rolling and vacuum drying, a nickel lead wire is welded with an ultrasonic welder to obtain a negative electrode plate, wherein the thickness of the plate is between 120 and 150 μm; The electrolyte preparation steps are as follows: non-aqueous solvents are mixed at a mass ratio of EC:EMC:DEC = 20:40:40, and LiPF with a concentration of 1 mol / L is added after mixing. 6 , add additives in the amounts shown in Table 1.

[0081] The diaphragm preparation steps are as follows: a polyethylene diaphragm with a thickness of 20 μm is used, and a solid electrolyte coating is coated on both sides of the diaphragm. The type and thickness of the solid electrolyte coating are shown in Table 1; The battery assembly steps are as follows: placing a separator between the positive plate and the negative plate, then winding the sandwich structure consisting of the positive plate, the negative plate and the separator, flattening the wound body and placing it in an aluminum-plastic shell, welding the pole ears and sealing the aluminum-plastic shell to obtain a battery cell to be injected with liquid; cutting and injecting the electrolyte prepared above into the battery cell, sealing it after standing for 1 hour, and aging the sealed battery at 45°C for 48 hours.

[0082] Then, the conventional formation of the first charge was carried out according to the following steps: 0.05C constant current charging for 3 h, 0.1C constant current charging for 2 h, 0.2C constant current charging for 2 h, standing for 1 hr, aging at 45°C for 48 h, and then further charged to 4.85 V at 0.2C constant current, and discharged to 3.4 V at 0.2C constant current.

[0083] Test high voltage interval capacity ratio V: First, at room temperature, the semi-solid-state battery is charged at a constant current and constant voltage of 0.1C to an upper limit voltage of 4.85V, and then discharged at a constant current of 0.1C to 3.4V. This is repeated twice to activate the battery within the total voltage range. Then, the battery was charged to the upper limit voltage at 0.5C constant current and constant voltage, and then discharged to 3.4V at 0.5C constant current, and the charging capacity during the charging and discharging process was recorded, wherein the charging capacity from the beginning of charging to charging to 4.85V is the charging capacity V1 of the total interval, and the charging capacity from charging to 4.5V to charging to 4.85V is the charging capacity V2 of the 4.5V~4.85V interval. The high-voltage interval capacity proportion V=V2 / V1*100% was calculated and recorded in Table 1.

[0084] Embodiments 2 to 20 Examples 2 to 20 are used to illustrate the method for preparing a semi-solid-state battery disclosed in the present invention, and include most of the operating steps in Example 1, except that: The positive electrode active material, the type and thickness of the solid electrolyte coating, the additives in the non-aqueous electrolyte and their mass contents are shown in Examples 2 to 20 in Table 1.

[0085] Comparative Examples 1 to 12 Comparative Examples 1 to 12 are used to illustrate the method for preparing a semi-solid-state battery disclosed in the present invention, and include most of the operating steps in Example 1, except that: The positive electrode active material, the type and thickness of the solid electrolyte coating, the additives in the non-aqueous electrolyte and their mass contents are shown in Comparative Examples 1 to 12 in Table 1.

[0086] Performance Testing The following tests were performed on the semi-solid batteries prepared in the above examples and comparative examples: 1) High temperature storage performance: Charge the formed battery to 4.85V at room temperature with 1C constant current and constant voltage, then discharge it to 3.4V with 1C constant current, record the initial discharge capacity, then charge it to 4.85V with 1C constant current and constant voltage, measure the initial volume of the battery by drainage method, then store it at 45℃ for 30 days, and after the battery cools to room temperature, test the volume after storage, and measure the battery retention capacity by discharging it to 3.4V with 1C. The calculation formula is as follows: Battery capacity retention rate (%) = retention capacity / initial discharge capacity × 100%; Battery gas expansion rate (%) = (volume after storage - initial volume) / initial volume × 100%; 2) Normal temperature cycle performance test: At 25°C, charge the formed battery to 4.85V with 1C constant current and constant voltage, and then discharge it to 3.4V with 1C constant current. After 1000 cycles of charge / discharge, calculate the retention rate of the 1000th cycle capacity. The calculation formula is as follows: 1000th cycle capacity retention rate (%) = (1000th cycle discharge capacity / first cycle discharge capacity) × 100%; (1) The test results obtained in Examples 1 to 14 and Comparative Examples 1 to 12 are entered in Table 2.

[0087] Table 2 It can be seen from the test results of Examples 1 to 14 and Comparative Examples 1 to 12 that in a semi-solid battery having a solid electrolyte coating on the diaphragm, fluoroethylene carbonate and boron-containing lithium salt additives are used as electrolyte additives, and the high-voltage range capacity proportion V of the semi-solid battery, the addition amount F of fluoroethylene carbonate and the addition amount L of the boron-containing lithium salt additive in the non-aqueous electrolyte, and the thickness S of the solid electrolyte coating are further controlled to satisfy the conditions 0.3≤S*V / 100*(L+1 / F)≤12.35, and 1≤S≤6, 0.3≤F≤4, 0.05≤L≤1.5, 70≤V≤95. The obtained semi-solid battery has a higher capacity retention rate and a lower expansion rate under high temperature storage, and at the same time has a longer cycle life under normal temperature circulation. It is speculated that in semi-solid batteries, fluoroethylene carbonate (FEC) and boron-containing lithium salt additives can form protective interfacial films on the surfaces of the positive and negative electrodes during the battery formation stage. These interfacial films are in direct contact with the solid electrolyte coating. By adjusting the ratio of FEC and boron-containing lithium salt additives, the composition of the interfacial film can be controlled, thereby optimizing its compatibility with the solid electrolyte coating. The high-voltage range capacity ratio V determines the thickness requirements of the solid electrolyte coating and the interfacial film. Specifically, the value of V affects the required thickness S of the solid electrolyte coating, and the choice of S in turn affects the thickness requirements of the interfacial film. Therefore, when the high-voltage range capacity ratio V of the semi-solid battery, the amount of FEC added in the non-aqueous electrolyte F, the amount of boron-containing lithium salt additive added L, and the thickness S of the solid electrolyte coating are in a synergistic state, the formed interfacial film can better adapt to the solid electrolyte coating and the working voltage, thereby ensuring a semi-solid battery with excellent electrochemical performance and stability.

[0088] From the comparison of the test results of Examples 1 to 14, it can be seen that when the high-voltage range capacity proportion V of the semi-solid-state battery, the addition amount F of fluoroethylene carbonate and the addition amount L of the boron-containing lithium salt additive in the non-aqueous electrolyte, and the thickness S of the solid electrolyte coating further satisfy the conditions 0.35≤S*V / 100*(L+1 / F)≤4.75, and 1.5≤S≤4.5, 0.5≤F≤3, 0.1≤L≤1, 80≤V≤90, the cycle performance and high-temperature storage performance of the semi-solid-state battery can be further improved.

[0089] From the test results of Comparative Examples 1 to 7, it can be seen that when the high-voltage range capacity proportion V of the semi-solid-state battery, the addition amount F of fluoroethylene carbonate in the non-aqueous electrolyte and the addition amount L of the boron-containing lithium salt additive, and the thickness S of the solid electrolyte coating do not meet their respective range limits, even if the limit of 0.3≤S*V / 100*(L+1 / F)≤12.35 is met, the obtained semi-solid-state battery does not have good high-temperature storage performance and room-temperature cycle life, indicating that too high or too low V value, F value, L value, and S value are not conducive to the improvement of high-temperature performance and cycle life of lithium-ion batteries; From the test results of Examples 8 to 12, it can be seen that when the V value, F value, L value, and S value do not satisfy the limitation of 0.3≤S*V / 100*(L+1 / F)≤12.35, even if they satisfy their respective content range limitations, it will also lead to the degradation of the high-temperature storage capacity retention rate of the semi-solid-state battery and the increase of gas production, indicating that there is a mutual influence between the high-pressure range capacity proportion V, fluoroethylene carbonate, boron-containing lithium salt additive and solid electrolyte coating. When and only when the four reach a good balance state, can they have a more obvious improvement on the performance of the battery.

[0090] (2) The test results obtained in Examples 1 and 15 to 17 are entered in Table 3.

[0091] Table 3 From the comparison of the test results of Examples 1 and 15 to 17, it can be seen that in the semi-solid battery system provided by the present invention, under the premise of satisfying the conditions 0.3≤S*V / 100*(L+1 / F)≤12.35, and 1≤S≤6, 0.3≤F≤4, 0.05≤L≤1.5, 70≤V≤95, using different solid electrolytes or using different boron-containing lithium salt additives can improve the high temperature storage performance and cycle life of the semi-solid battery to a certain extent, indicating that the semi-solid battery system provided by the present invention is suitable for different solid electrolytes or using different boron-containing lithium salt additives.

[0092] (3) The test results obtained in Examples 1, 18 to 20 are entered in Table 4.

[0093] Table 4 From the comparison of the test results of Examples 1 and 18 to 20, it can be seen that in the semi-solid battery system provided by the present invention, further adding PS (1,3-propane sultone), DTD (vinyl sulfate) or VC (vinylene carbonate) is beneficial to further improve the electrochemical performance of the semi-solid battery, indicating that the performance improvement mechanism of PS (1,3-propane sultone), DTD (vinyl sulfate) or VC (vinylene carbonate) for the battery is different from that of fluoroethylene carbonate, and can improve the electrochemical performance of the semi-solid battery from different aspects.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A semi-solid-state battery, characterized in that: The invention comprises a positive electrode, a negative electrode, a separator and a non-aqueous electrolyte, wherein the separator is located between the positive electrode and the negative electrode, at least one surface of the separator is provided with a solid electrolyte coating, the non-aqueous electrolyte comprises a non-aqueous organic solvent, a lithium salt and an additive, and the additive comprises fluoroethylene carbonate and a boron-containing lithium salt additive; The semi-solid-state battery meets the following conditions: 0.3≤S*V / 100*(L+1 / F)≤12.35, and 1≤S≤6, 0.3≤F≤4, 0.05≤L≤1.5, 70≤V≤95; Wherein, S is the thickness of the solid electrolyte coating, in μm; F is the mass percentage of fluoroethylene carbonate in the non-aqueous electrolyte, unit is %; L is the mass percentage of the boron-containing lithium salt additive in the non-aqueous electrolyte, in %; V is the capacity ratio in the high-voltage range, which is the percentage of the charging capacity of the semi-solid-state battery in the 4.5V~5V range to the charging capacity in the total range of 3.4V~5V, in %.

2. The semi-solid-state battery according to claim 1, characterized in that: The semi-solid-state battery meets the following conditions: 0.35≤S*V / 100*(L+1 / F)≤4.

75.

3. The semi-solid-state battery according to claim 1, characterized in that: The thickness S of the solid electrolyte coating is 1.5-4.5 μm.

4. The semi-solid-state battery according to claim 1, characterized in that: The mass percentage F of fluoroethylene carbonate in the non-aqueous electrolyte is 0.5% to 3%.

5. The semi-solid-state battery according to claim 1, characterized in that: The mass percentage L of the boron-containing lithium salt additive in the non-aqueous electrolyte is 0.1% to 1%.

6. The semi-solid-state battery according to claim 1, characterized in that: The high-voltage interval capacity proportion V is 80%~90%.

7. The semi-solid-state battery according to claim 1, characterized in that: The solid electrolyte coating includes a solid electrolyte, and the solid electrolyte includes at least one of lithium aluminum titanium phosphate, lithium titanium phosphate, lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide, lithium tetrathiophosphate, lithium germanium phosphosulfur sulfide, and lithium phosphosulfur chloride.

8. The semi-solid-state battery according to claim 1, characterized in that: The boron-containing lithium salt additive includes at least one of LiODFB and LiBOB.

9. The semi-solid-state battery according to claim 1, characterized in that: The additive further comprises at least one of a cyclic sulfate compound, a sultone compound, a cyclic carbonate compound, a phosphate compound, a borate compound and a nitrile compound; The cyclic sulfate ester compound includes at least one of vinyl sulfate, 1,3,2-dioxathiacyclohexane-2,2-dioxide, and methyl vinyl sulfate; and / or The sultone compound includes at least one of 1,3-propane sultone, 1,4-butane sultone and 1,3-propene sultone; and / or The cyclic carbonate compound includes at least one of vinylene carbonate, vinyl ethylene carbonate, methylene carbonate or the compound shown in structural formula 1: Structural formula 1 In the structural formula 1, R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Each is independently selected from a hydrogen atom, a halogen atom, a C1-C5 group; and / or The phosphate compound includes at least one of tris(trimethylsilyl)phosphate, tris(triethylsilyl)phosphate or the compound shown in structural formula 2: Structural formula 2 In the structural formula 2, R 31 , R 32 , R 33 Each is independently selected from a C1-C5 saturated hydrocarbon group, a C1-C5 unsaturated hydrocarbon group, a C1-C5 halogenated hydrocarbon group, -Si(C m H 2m+1 )3, m is a natural number from 1 to 3, and R 31 , R 32 , R 33 At least one of them is an unsaturated hydrocarbon group; and / or The borate compound comprises at least one of tris(trimethylsilyl)borate and tris(triethylsilyl)borate; and / or The nitrile compound includes at least one of succinonitrile, glutaronitrile, hexanetrinitrile, adiponitrile, pimelonitrile, suberonitrile, azelaic acid dinitrile and sebacononitrile.

10. The semi-solid-state battery according to claim 1, characterized in that: The positive electrode includes a positive electrode material layer containing a positive electrode active material, and the positive electrode active material includes at least one of the compounds represented by Formula (A) or Formula (B): LiNi x M 2-x A y O r B p Formula (A) nLi2MnO3·(1-n)LiMO2 Formula (B) In Formula (A), 0 ≤ x ≤ 1, 1 ≤ 2 - x ≤ 2, 0 ≤ y ≤ 0.05, 1 ≤ r ≤ 4, 0 ≤ p ≤ 4, r + p ≤ 4, M includes at least one of Mn and Al, A includes at least one of Zr, Zn, Cu, Cr, Fe, V, Ti, Sr, Sb, Sn, Y, W, Al, and Nb, and B includes at least one of F, Cl, and Br; In Formula (B), 0 < n < 1, and M includes at least one of Ni, Co, Mn, and Al.

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