An electrochemical device and an electronic device

Abstract

The application provides an electrochemical device and an electronic device, wherein the electrochemical device comprises an electrolyte, the electrolyte comprises a compound of formula (I) and a polymerization monomer, the mass percentage of the compound of formula (I) is m%, 0.01<=m<=5, and the mass percentage of the polymerization monomer is n%, 0.5<=n<=10, based on the mass of the electrolyte. By selecting the compound of formula (I) and the polymerization monomer, and adjusting the mass percentage of the compound of formula (I) and the mass percentage of the polymerization monomer within the above range, the cycle performance of the electrochemical device under high voltage and high discharge rate can be improved.

Description

Technical Field

[0001] This application relates to the field of electrochemical technology, and in particular to an electrochemical device and an electronic device. Background Technology

[0002] As the 3C digital market demands increasingly higher energy density and lower costs for electrochemical devices (such as lithium-ion batteries), the current approach typically involves developing solid-state electrolytes to improve energy density and reduce costs. However, existing solid-state electrolytes exhibit poor cycle performance at high voltages and high discharge rates, thus failing to completely replace common oxide solid-state electrolytes. This limits the cycle performance of lithium-ion batteries at high voltages and high discharge rates, such as voltages greater than or equal to 4.2V and discharge rates greater than or equal to 0.5C. Therefore, improving the cycle performance of lithium-ion batteries at high voltages and high discharge rates has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0003] This application provides an electrochemical device and an electronic device to improve the cycling performance of the electrochemical device under high voltage and high discharge rate.

[0004] It should be noted that while this application uses lithium-ion batteries as an example of an electrochemical device to explain the invention, the electrochemical device described herein is not limited to lithium-ion batteries. The specific technical solution is as follows:

[0005] A first aspect of this application provides an electrochemical device, including an electrolyte comprising a compound of formula (I) and a polymeric monomer:

[0006]

[0007] Wherein, X1 and X2 are each independently selected from Ra-substituted or unsubstituted C2 to C5 heterocyclic groups and Ra-substituted or unsubstituted C6 to C9 aryl groups, and the heteroatoms in the heterocyclic groups are selected from at least one of N, O, or S; the substituent Ra of each group is each independently selected from Rb-substituted or unsubstituted C1 to C5 heterocyclic groups. 12 Alkyl, Rb-substituted or unsubstituted C2 to C3 12 Alkenyl, Rb-substituted or unsubstituted C2 to C5 heterocyclic groups, Rb-substituted or unsubstituted C6 to C5 heterocyclic groups 12 Aryl group; the substituents Rb of each group are independently selected from C1 to C6 alkyl, C2 to C6 alkenyl, C6 to C6 alkyl, C2 to C6 alkenyl, C6 to C6 alkenyl, C2 ... 12 aryl, C1 to C6 alkoxy, C6 to C 12The compound comprises at least one of the following: aryloxy group, C1 to C6 ester group, Si1 to Si6 silyl group, Si1 to Si6 siloxane group, amino group, ether group, carbonyl group, carboxyl group, sulfonic acid group, mercapto group, nitro group, cyano group, or halogen group; the polymerizable monomer comprises at least one of the following: methyl acrylate, methyl methacrylate, vinylene carbonate, ethylene ethylene carbonate, ethylene, propylene, vinyl acetate, difluoroethylene, tetrafluoroethylene, hexafluoropropylene, acrylonitrile, ethylene glycol, ethylene glycol diacrylate, diethylene glycol diacrylate, ethylene oxide, dioxopentane, 2,6-dimethylphenol, 3,4-ethylenedioxothiophene, or 4,6-diamino-1,3-m-diphenol; based on the mass of the electrolyte, the mass percentage of the compound of formula (I) is m%, 0.01≤m≤5, preferably 0.5≤m≤4, and the mass percentage of the polymerizable monomer is n%, 0.5≤n≤10, preferably 2≤n≤8. By selecting the above-mentioned compounds of formula (I) and polymeric monomers, and controlling the mass percentage of the compounds of formula (I) and the mass percentage of the polymeric monomers within the above-mentioned ranges, the cycle performance of the electrochemical device under high voltage and high discharge rate can be improved.

[0008] For example, compounds of formula (I) include at least one of the following compounds: (I-1) to (I-10):

[0009]

[0010] In some embodiments of this application, the molar mass of the compound of formula (I) is M. (I) g / mol, the molar mass of the polymerized monomer is M 单 g / mol, m, n, M (I) and M 单 The following condition must be met: 1.5 ≤ (n / M) 单 ) / (m / M (I) )≤100, preferably, 4.8≤(n / M) 单 ) / (m / M (I) )≤60. (n / M) 单 ) / (m / M (I) Adjusting the value of ) within the above range is beneficial to improving the cycle performance and charging rate window of the electrochemical device.

[0011] In some embodiments of this application, the electrochemical device includes a positive electrode, which includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector. The positive electrode material layer includes a positive electrode active material and an inorganic solid electrolyte. Based on the mass of the positive electrode material layer, the mass percentage of the inorganic solid electrolyte is θ%, 0.005≤θ≤6. By controlling the mass percentage of the inorganic solid electrolyte in the positive electrode material layer within the above range, in conjunction with the content of the compound of formula (I) and the polymer monomer, the cycle performance of the electrochemical device under high voltage and high discharge rate can be further improved.

[0012] In some embodiments of this application, 0.1 ≤ n / θ ≤ 100. By adjusting the value of n / θ within the above range, the cycling performance of the electrochemical device at high voltage and high discharge rate is improved.

[0013] In some embodiments of this application, 0.005 ≤ θ ≤ 5 and / or 0.5 ≤ n / θ ≤ 100.

[0014] In some embodiments of this application, the inorganic solid electrolyte is a NASICON structural material; the inorganic solid electrolyte includes Li 1+a Al a Ge 2-a (PO4)3, Li 1+a Al a Ge 2-a (PO4)3 heteroatom doped compounds, Li 1+b Al b Ti 2-b (PO4)3, Li 1+b Al b Ti 2-b (PO4)3 heteroatom doped compounds or Li 6.5 La3Zr 1.5 Ta 0.5 O 12 At least one of the following: wherein 0 ≤ a ≤ 0.75, 0 ≤ b ≤ 0.5, and each heteroatom is independently selected from at least one of Y, Ga, Cr, In, Se, Zr, Sn, Fe, V, Hf, Mg, Nb, Sr, and Pr. The above-mentioned inorganic solid electrolyte exhibits good conductivity and oxidation resistance, and is compatible with the electrolyte provided in this application, thereby improving the cycle performance of the electrochemical device under high voltage and high discharge rate.

[0015] In some embodiments of the present application, the electrolyte further comprises an initiator, wherein the initiator comprises at least one of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azodiisobutyrate or methyl ethyl ketone peroxide; based on the mass of the electrolyte, the mass percentage of the initiator is 0.001% to 2%, preferably 0.05% to 1%. When the electrolyte comprises the initiator of the above kind and the mass percentage of the initiator in the electrolyte is controlled within the above range, the cycle performance of the electrochemical device under high voltage and high discharge rate can be improved.

[0016] In some embodiments of the present application, the electrolyte further comprises an additive containing an unsaturated bond, wherein the additive containing an unsaturated bond comprises at least one of fluoroethylene carbonate, vinylene carbonate, vinyl ethylene carbonate, 1,3-propene sultone, 1,3-propane sultone, 3-hexenedinitrile, fumaric anhydride or triallyl methoxysilane; based on the mass of the electrolyte, the mass percentage of the additive containing an unsaturated bond is 0.01% to 30%, preferably 0.01% to 20%. When the electrolyte comprises the above-mentioned additive containing an unsaturated bond and the mass percentage of the additive containing an unsaturated bond is controlled within the above range, the cycle performance of the electrochemical device under high voltage and high discharge rate can be further improved.

[0017] In some embodiments of the present application, the positive electrode active material comprises LiCoO₂, LiNiO₂, LiMnO₂, LiNi 0.5 Mn 1.5 O₄, LiNi x Co 1-x O₂, LiNi x Co y Mn 1-x-y O₂, LiNi x Co y Al 1-x-y O₂ and at least one of modified compounds thereof, wherein 0<x<1, 0<y<1, 0<x+y<1, and x and y in each compound are the same or different. By selecting the above positive electrode active material, the electrochemical device has a higher energy density while having good cycle performance under high voltage and high discharge rate.

[0018] In some embodiments of this application, the electrolyte further includes an organic solvent, which includes at least one of carbonates, carboxylic acid esters, or ethers; the carbonate includes at least one of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, propylene carbonate, ethylene carbonate, dipropyl carbonate, methyl propyl carbonate, fluoroethylene carbonate, difluoroethylene carbonate, pentafluoropropyl ethylene carbonate, methyl trifluoroethyl carbonate, trifluoromethyl ethylene carbonate, or bis(2,2,2-trifluoroethyl) carbonate; the carboxylic acid ester includes propyl propionate, ethyl propionate, ethyl acetate, ethyl formate, methyl acetate, methyl propionate, propyl acetate, butyl butyrate, ethyl difluoroacetate, difluoroethyl acetate, and ethyl trifluoroacetate. The electrolyte contains at least one of trifluoroethyl acetate or methyl trifluoropropionate, and the ether comprises at least one of 1,3-dioxane, 1,4-dioxane, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol formate ethyl ether, diethoxymethane, 1,3-dimethoxypropane, 1,1,3,3-tetraethoxypropane ether, or 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether; based on the mass of the electrolyte, the carbonate content is 20% to 80% by mass, the carboxylic acid ester content is 0% to 60% by mass, and the ether content is 0% to 40% by mass.

[0019] In some embodiments of this application, the electrolyte further includes a lithium salt, which includes at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium tetraphenylborate, lithium methanesulfonate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, lithium tris(trifluoromethanesulfonyl)methyl lithium, lithium hexafluorosilicate, lithium dioxalateborate, or lithium difluorooxalateborate; the lithium salt has a mass percentage content of 6% to 20% based on the mass of the electrolyte.

[0020] A second aspect of this application provides an electronic device comprising the electrochemical device described in any of the foregoing embodiments. Therefore, the electronic device exhibits good performance in use.

[0021] This application provides an electrochemical device and an electronic device, wherein the electrochemical device includes an electrolyte comprising a compound of formula (I) and a polymeric monomer. Based on the mass of the electrolyte, the mass percentage of the compound of formula (I) is m%, 0.01 ≤ m ≤ 5, and the mass percentage of the polymeric monomer is n%, 0.5 ≤ n ≤ 10. By selecting the compound of formula (I) and the polymeric monomer of this application, and by controlling the mass percentage of the compound of formula (I) and the mass percentage of the polymeric monomer within the above-mentioned ranges, the cycle performance of the electrochemical device under high voltage and high discharge rate can be improved. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following embodiments are provided to further illustrate this application in detail. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in this application are within the scope of protection of this application.

[0023] It should be noted that, in the specific embodiments of this application, a lithium-ion battery is used as an example of an electrochemical device to explain this application; however, the electrochemical device of this application is not limited to lithium-ion batteries. The specific technical solution is as follows:

[0024] A first aspect of this application provides an electrochemical device, including an electrolyte comprising a compound of formula (I) and a polymeric monomer:

[0025]

[0026] Wherein, X1 and X2 are each independently selected from Ra-substituted or unsubstituted C2 to C5 heterocyclic groups and Ra-substituted or unsubstituted C6 to C9 aryl groups, and the heteroatoms in the heterocyclic groups are selected from at least one of N, O, or S; the substituent Ra of each group is each independently selected from Rb-substituted or unsubstituted C1 to C5 heterocyclic groups. 12 Alkyl, Rb-substituted or unsubstituted C2 to C3 12 Alkenyl, Rb-substituted or unsubstituted C2 to C5 heterocyclic groups, Rb-substituted or unsubstituted C6 to C5 heterocyclic groups 12 Aryl group; the substituents Rb of each group are independently selected from C1 to C6 alkyl, C2 to C6 alkenyl, C6 to C6 alkyl, C2 to C6 alkenyl, C6 to C6 alkenyl, C2 ... 12 aryl, C1 to C6 alkoxy, C6 to C 12The compound comprises at least one of the following: aryloxy group, C1 to C6 ester group, Si1 to Si6 silyl group, Si1 to Si6 siloxane group, amino group, ether group, carbonyl group, carboxyl group, sulfonic acid group, mercapto group, nitro group, cyano group, or halogen group; the polymerizable monomer comprises at least one of the following: methyl acrylate, methyl methacrylate, vinylene carbonate, ethylene ethylene carbonate, ethylene, propylene, vinyl acetate, difluoroethylene, tetrafluoroethylene, hexafluoropropylene, acrylonitrile, ethylene glycol, ethylene glycol diacrylate, diethylene glycol diacrylate, ethylene oxide, dioxopentane, 2,6-dimethylphenol, 3,4-ethylenedioxothiophene, or 4,6-diamino-1,3-m-diphenol; based on the mass of the electrolyte, the mass percentage of the compound of formula (I) is m%, 0.01≤m≤5, preferably 0.5≤m≤4, and the mass percentage of the polymerizable monomer is n%, 0.5≤n≤10, preferably 2≤n≤8. For example, m can be 0.01, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, or any value between any two of the above ranges. n can be 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or any value between any two of the above ranges.

[0027] Through extensive research, the inventors discovered that the compound of formula (I) possesses cross-linking polymerization and metal ion complexation functions. When both the compound and the monomer of this application are controlled within the aforementioned content range, a structure similar to organometallic molecules (MOFs) can be generated on the positive electrode. This structure, serving as the network framework of the positive electrolyte interfacial film (CEI), combines rigidity and flexibility, effectively blocking contact between the liquid electrolyte and the positive electrode and suppressing the oxidative decomposition of organic solvents under high voltage. Furthermore, this structure, as the network framework of the CEI, also exhibits low impedance, providing fast ion transport channels and broadening the rate window of the electrochemical device. During the charge-discharge cycle of the electrochemical device, the monomer of this application can undergo a repair polymerization reaction with polymers (such as binders) in the positive electrode, helping to maintain the adhesion of the binder and the network structure of the conductive agent in the positive electrode material layer, thereby extending the cycle life of the electrochemical device. If the mass percentage of compound (I) is less than 0.01% and / or the mass percentage of polymeric monomer is less than 0.5%, insufficient organic polymer formation can easily lead to poor contact between the inorganic solid electrolyte and the positive electrode active material particles, thereby increasing the interfacial impedance of the positive electrode / inorganic solid electrolyte and increasing the polarization of the electrochemical device. If the mass percentage of compound (I) is greater than 5% and / or the mass percentage of polymeric monomer is greater than 10%, excessive organic polymer formation can easily lead to an increase in the lithium-ion desolvation energy barrier, resulting in excessive interfacial impedance of the positive electrode / inorganic solid electrolyte, lithium plating during charging, and more residual polymeric monomer, which continuously reacts and consumes lithium ions during charging and discharging, leading to rapid capacity decay of the electrochemical device. Therefore, by selecting the above-mentioned types of compound (I) and polymeric monomer, and controlling the mass percentage of compound (I) and polymeric monomer within the above-mentioned ranges, the cycle performance of the electrochemical device under high voltage and high discharge rate can be improved. In this application, high voltage means a voltage greater than or equal to 4.25V, and high discharge rate means a discharge rate greater than 0.5C.

[0028] For example, compounds of formula (I) include at least one of the following compounds: (I-1) to (I-10):

[0029]

[0030] Using the compound of formula (I) above is beneficial to improving the cycle performance of electrochemical devices under high voltage and high discharge rate.

[0031] For example, C2 to C5 heterocyclic groups are selected from the following groups:

[0032]

[0033] For example, C6 to C9 aryl groups are selected from the following groups:

[0034]

[0035] In this application, "*" indicates a connection site.

[0036] In some embodiments of this application, the molar mass of the compound of formula (I) is M. (I) g / mol, the molar mass of the polymerized monomer is M 单 g / mol, m, n, M (I) and M 单 The following condition must be met: 1.5 ≤ (n / M) 单 ) / (m / M (I) )≤100, preferably, 4.8≤(n / M) 单 ) / (m / M (I) )≤60. For example, (n / M 单 ) / (m / M (I) The value of (n / M) is 1.5, 3, 4.8, 10, 20, 30, 50, 60, 70, 80, 90, 100, or any value between any two of the above ranges. 单 ) / (m / M (I) By controlling the value of (I) within the aforementioned range, the compound and monomer of formula (I) can achieve directional control over the composition of repeating block polymer units and design the polymer type. The resulting organic polymer, as an artificial CEI, possesses more suitable rigidity and flexibility, which is beneficial for blocking the contact between the electrolyte and the positive electrode, suppressing the oxidative decomposition of organic solvents in the electrolyte under high voltage, and further reducing the impedance of the electrochemical device and widening its rate window. This, in turn, improves the cycle performance and charging rate window of the electrochemical device.

[0037] It should be noted that when two or more polymeric monomers and / or two or more compounds of formula (I) are selected in the electrolyte, (n / M 单 ) / (m / M (I) This can also be understood as ∑(n / M) 单 ) / ∑(m / M (I) ).

[0038] In some embodiments of this application, the electrochemical device includes a positive electrode, which includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector. The positive electrode material layer includes a positive electrode active material and an inorganic solid electrolyte. Based on the mass of the positive electrode material layer, the mass percentage of the inorganic solid electrolyte is θ%, 0.005 ≤ θ ≤ 6. For example, the value of θ is 0.001, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, or any value between any two of the above ranges. The inorganic solid electrolyte and the organic polymer together serve as an artificial CEI. The inorganic solid electrolyte has good conductivity and oxidation resistance, which can improve the rate performance and high voltage stability of the positive electrode. The organic polymer is formed by the polymerization reaction of monomers in the electrolyte, which can improve the contact between the inorganic solid electrolyte and the positive electrode active material, reduce the impedance of the positive electrode, and enhance the electrochemical stability of the positive electrode. By controlling the mass percentage of inorganic solid electrolyte in the cathode material layer within the above range, and matching it with the content of compound (I) and polymer monomer, the cycling performance of the electrochemical device under high voltage and high discharge rate can be further improved.

[0039] Those skilled in the art should understand that the above-mentioned "positive electrode material layer disposed on at least one surface of the positive electrode current collector" means that the positive electrode material layer can be disposed on one surface of the positive electrode current collector or on two surfaces of the positive electrode current collector, and the above-mentioned "surface" refers to all or part of the surface of the positive electrode current collector.

[0040] In some embodiments of this application, 0.1 ≤ n / θ ≤ 100, preferably 0.5 ≤ n / θ ≤ 100. For example, the value of n / θ is 0.1, 0.5, 1, 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, or any value between any two of the above ranges. Inorganic solid electrolytes have good conductivity and oxidation resistance, and also function as fast ion conductors. By controlling the value of n / θ within the above range, the contact interface between the inorganic solid electrolyte and the positive electrode active material (e.g., a positive electrode active material with a nickel content of not less than 80%) is well-densed. The CEI film generated by the in-situ polymerization of the monomers has a good protective effect on the positive electrode active material, reducing the possibility of irreversible crystal phase destruction and rapid capacity decay of the positive electrode active material during the charge-discharge cycle of the electrochemical device. Furthermore, the electrolyte has a suitable degree of polymerization, and there are sufficient liquid components remaining after the polymerization of the monomers, resulting in a low impedance of the electrochemical device. As a result, the cycling performance of the electrochemical device is improved under high voltage and high discharge rate.

[0041] Preferably, 0.005 ≤ θ ≤ 5. For example, the value of θ is 0.005, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, or any value between any two of the above ranges. Controlling the mass percentage of the inorganic solid electrolyte in the cathode material layer within the above-mentioned preferred range is beneficial for further improving the cycle performance of the electrochemical device under high voltage and high discharge rate.

[0042] Preferably, 0.5 ≤ n / θ ≤ 100. For example, the value of n / θ is 0.5, 1, 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, or any value between any two of the above ranges. Adjusting the value of n / θ within the above preferred range is beneficial for further improving the cycle performance of the electrochemical device under high voltage and high discharge rate.

[0043] Preferably, 0.005 ≤ θ ≤ 5, and 0.5 ≤ n / θ ≤ 100. By simultaneously controlling the mass percentage of the inorganic solid electrolyte in the positive electrode material layer and the value of n / θ within the above-mentioned preferred ranges, the cycle performance of the electrochemical device under high voltage and high discharge rate can be further improved.

[0044] In some embodiments of this application, the inorganic solid electrolyte is a NASICON structural material; the inorganic solid electrolyte includes Li 1+a Al a Ge 2-a (PO4)3, Li 1+a Al a Ge 2-a (PO4)3 heteroatom doped compounds, Li 1+b Al b Ti 2-b (PO4)3, Li 1+b Al b Ti 2-b (PO4)3 heteroatom doped compounds or Li 6.5 La3Zr 1.5 Ta 0.5 O 12 At least one of the following: wherein 0 ≤ a ≤ 0.75, 0 ≤ b ≤ 0.5, and each heteroatom is independently selected from at least one of Y, Ga, Cr, In, Se, Zr, Sn, Fe, V, Hf, Mg, Nb, Sr, and Pr. The above-mentioned inorganic solid electrolyte possesses good conductivity and oxidation resistance, matching the electrolyte provided in this application. The inorganic solid electrolyte and the organic polymer formed by the polymer monomers together serve as an artificial CEI, providing good interfacial protection for the positive electrode active material, thereby improving the rate performance and high voltage stability of the positive electrode, and thus enhancing the cycle performance of the electrochemical device under high voltage and high discharge rate.

[0045] In some embodiments of this application, the electrolyte further includes an initiator, which includes at least one selected from azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, or methyl ethyl ketone peroxide; the mass percentage of the initiator is 0.001% to 2%, preferably 0.05% to 1%, based on the mass of the electrolyte. For example, the mass percentage of the initiator is 0.001%, 0.01%, 0.05%, 0.1%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, or any value between any two of the above ranges. The electrolyte contains the above-mentioned initiators, and the mass percentage of the initiator in the electrolyte is controlled within the above-mentioned range. The initiator can further enhance the polymerization effect of the monomers, forming organic polymers that better adhere to the surface of the positive electrode active material and / or the surface of the inorganic solid electrolyte, thereby blocking the contact between the electrolyte and the positive electrode, inhibiting the oxidative decomposition of organic solvents in the electrolyte under high voltage, reducing the impedance of the electrochemical device, and thus improving the cycle performance of the electrochemical device under high voltage and high discharge rate.

[0046] In this application, the monomers can also undergo polymerization via electro-initiation (current-catalyzed polymerization), photo-initiation (ultraviolet photocatalyzed polymerization), or thermal initiation (high-temperature catalyzed polymerization), or polymerization can be initiated by an initiator under any of the above initiation methods, to form monomers or oligomers of the main chain segments and functional chain segments of the organic polymer, which adhere to the surface of the positive electrode active material or the surface of the inorganic solid electrolyte. In this application, the polymerization of monomers to form the organic polymer is generated during the electrochemical device manufacturing process. For example, during the electrolyte injection stage, monomers are added to the electrolyte and then polymerized via thermal initiation, or during the formation stage, polymerization is initiated via electro-initiation.

[0047] In some embodiments of the present application, the electrolyte further comprises an additive containing an unsaturated bond, and the additive containing an unsaturated bond comprises at least one of fluoroethylene carbonate, vinylene carbonate, vinyl ethylene carbonate, 1,3-propene sultone, 1,3-propane sultone, 3-hexenedinitrile, fumaric anhydride or triallylmethoxysilane; based on the mass of the electrolyte, the mass percentage of the additive containing an unsaturated bond is 0.01% to 30%, preferably 0.01% to 20%. For example, the mass percentage of the additive containing an unsaturated bond is 0.01%, 0.05%, 1%, 10%, 15%, 20%, 25%, 30%, or any value between any two of the above numerical ranges. When the electrolyte comprises the above-mentioned type of additive containing an unsaturated bond, and the mass percentage of the additive containing an unsaturated bond is controlled within the above-mentioned range, the additive containing an unsaturated bond undergoes a copolymerization reaction with the polymerizable monomer, and the formed copolymer also has the effect of adjusting the physical and electrochemical properties of the aforementioned organic polymer, and can also improve the ionic conductivity, oxidation resistance or reduction resistance window of the copolymer, produce a synergistic effect, and further improve the cycling performance of the electrochemical device under high voltage and high discharge rate conditions.

[0048] In the present application, the above-mentioned "unsaturated bond" refers to double bonds, triple bonds and rings formed by bonding of carbon, nitrogen, oxygen, sulfur, phosphorus and other elements.

[0049] In some embodiments of the present application, the positive electrode active material comprises LiCoO2, LiNiO2, LiMnO2, LiNi 0.5 Mn 1.5 O4, LiNi x Co 1-x O2, LiNi x Co y Mn 1-x-y O2, LiNi x Co y Al 1-x-y O2 and at least one of modified compounds thereof, wherein 0<x<1, 0<y<1, 0<x+y<1, and x and y in each compound are the same or different. With the selection of the above positive electrode active material, the electrochemical device has higher energy density while maintaining good cycling performance under high voltage and high discharge rate conditions.

[0050] In some embodiments of this application, the electrolyte further includes an organic solvent, which includes at least one of carbonates, carboxylic esters, or ethers; in one embodiment, the organic solvent includes carbonates; in one embodiment, the organic solvent includes carboxylic esters; in one embodiment, the organic solvent includes ethers; in one embodiment, the organic solvent includes both carbonates and carboxylic esters; in one embodiment, the organic solvent includes both carbonates and ethers; in one embodiment, the organic solvent includes both carboxylic esters and ethers; in one embodiment, the organic solvent includes carbonates, carboxylic esters, and ethers. Carbonates include at least one of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, propylene carbonate, ethylene carbonate, dipropyl carbonate, methyl propyl carbonate, fluoroethylene carbonate, difluoroethylene carbonate, pentafluoropropyl ethylene carbonate, methyl trifluoroethyl carbonate, trifluoromethyl ethylene carbonate, or bis(2,2,2-trifluoroethyl) carbonate; carboxylic acid esters include at least one of propyl propionate, ethyl propionate, ethyl acetate, ethyl formate, methyl acetate, methyl propionate, propyl acetate, butyl butyrate, ethyl difluoroethyl acetate, difluoroethyl acetate, ethyl trifluoroethyl acetate, trifluoroethyl acetate, or methyl trifluoropropionate; ether-containing... The electrolyte comprises at least one of 1,3-dioxane, 1,4-dioxane, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, ethylene glycol formate ethyl ether, diethoxymethane, 1,3-dimethoxypropane, 1,1,3,3-tetraethoxypropane ether, or 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether; based on the mass of the electrolyte, the carbonate content is 20% to 80% by mass, the carboxylic acid ester content is 0% to 60% by mass, and the ether content is 0% to 40% by mass. For example, the mass percentage of carbonates can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, or any value within any two of the above ranges; the mass percentage of carboxylic acid esters can be 0%, 10%, 20%, 30%, 40%, 50%, 60%, or any value within any two of the above ranges; and the mass percentage of ethers can be 0%, 10%, 20%, 30%, 40%, or any value within any two of the above ranges. Using the above-mentioned organic solvents and controlling the mass percentages of carbonates, carboxylic acid esters, and ethers in the electrolyte within the above ranges is beneficial for ensuring good wettability of the electrolyte to both the positive and negative electrode active materials, improving the lithium-ion transport rate, and ensuring good stability of the electrolyte, reducing the risk of electrolyte decomposition and gas generation, thereby improving the cycle performance of the electrochemical device at high voltage and high rate.

[0051] In some embodiments of this application, the electrolyte further includes a lithium salt, which includes at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), lithium perchlorate (LiClO4), lithium tetraphenylborate (LiB(C6H5)4), lithium methanesulfonate (LiCH3SO3), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiCF3SO3(LiTA)), lithium bis(trifluoromethanesulfonyl)imide (LiN(SO2CF3)2(LiTFSI)), lithium tris(trifluoromethanesulfonyl)methyl (LiC(SO2CF3)3), lithium hexafluorosilicate (LiSiF6), lithium dioxolaneborate (LiBOB), or lithium difluorooxolaneborate (LiDFOB); the lithium salt has a mass percentage content of 6% to 20% based on the mass of the electrolyte. For example, the mass percentage of lithium salts can be 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, or any value between any two of the above ranges. Selecting the above types of lithium salts and controlling their mass percentage in the electrolyte within the above ranges is beneficial for accelerating lithium ion transport and improving the cycle performance of the electrochemical device.

[0052] This application does not impose any particular limitation on the positive electrode current collector, as long as it achieves the purpose of this application. For example, the positive electrode current collector may include aluminum foil, aluminum alloy foil, or composite current collectors. In this application, there are no particular limitations on the thickness of the positive electrode current collector and the positive electrode material layer, as long as it achieves the purpose of this application. For example, the thickness of the positive electrode current collector is 5 μm to 20 μm, preferably 6 μm to 18 μm. The thickness of the single-sided positive electrode material layer is 30 μm to 120 μm. Optionally, the positive electrode material layer may also include a conductive agent and a binder. This application does not impose any particular limitation on the types of conductive agents and binders in the positive electrode material layer, as long as they achieve the purpose of this application. This application does not impose any particular limitation on the mass ratio of positive electrode active material, conductive agent, and binder in the positive electrode material layer; those skilled in the art can choose according to actual needs, as long as it achieves the purpose of this application. For example, the mass ratio of positive electrode active material, conductive agent, and binder in the positive electrode material layer is (80–99.9):(0.005–6):(0.01–6).

[0053] The electrochemical device of this application may further include a negative electrode sheet. This application does not impose any particular limitation on the negative electrode sheet, as long as it achieves the purpose of this application. For example, the negative electrode sheet includes a negative current collector and a negative electrode material layer. This application does not impose any particular limitation on the negative current collector, as long as it achieves the purpose of this application. For example, the negative current collector may include copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, or copper foam, etc. The negative electrode active material layer of this application includes a negative electrode active material. This application does not impose any particular limitation on the type of negative electrode active material, as long as it achieves the purpose of this application. For example, the negative electrode active material may include, but is not limited to, natural graphite, artificial graphite, mesophase microcarbon spheres, hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, and spinel-structured lithiated TiO2-Li4Ti5O. 12 Or at least one of Li-Al alloys. In this application, there are no particular limitations on the thickness of the negative electrode current collector and the negative electrode active material layer, as long as the purpose of this application is achieved. For example, the thickness of the negative electrode current collector is 6 μm to 10 μm, and the thickness of the negative electrode active material layer is 30 μm to 130 μm. Optionally, the negative electrode active material layer may further include at least one of a conductive agent, a stabilizer, and a binder. This application does not particularly limit the types of conductive agents, stabilizers, and binders in the negative electrode active material layer, as long as the purpose of this application is achieved. This application does not particularly limit the mass ratio of the negative electrode active material, conductive agent, stabilizer, and binder in the negative electrode active material layer, as long as the purpose of this application is achieved. For example, the mass ratio of the negative electrode active material, conductive agent, binder, and stabilizer in the negative electrode active material layer is (75–95):(0.01–8):(0.01–20):(1–10).

[0054] The electrochemical device of this application may also include a diaphragm. This application does not impose any particular limitation on the diaphragm, as long as it achieves the purpose of this application. For example, the diaphragm material may include, but is not limited to, at least one of polyethylene (PE), polyolefin (PO) primarily composed of polypropylene (PP), polyester (e.g., polyethylene terephthalate (PET)), cellulose, polyimide (PI), polyamide (PA), spandex, or aramid; the diaphragm type may include, but is not limited to, at least one of woven membrane, nonwoven membrane (non-woven fabric), microporous membrane, composite membrane, diaphragm paper, rolled membrane, or spun membrane. For example, the diaphragm may include a substrate layer and a surface treatment layer. The substrate layer may be a nonwoven fabric, membrane, or composite membrane with a porous structure, and the material of the substrate layer may include at least one of polyethylene, polypropylene, polyethylene terephthalate, or polyimide. Optionally, a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite membrane may be used. Optionally, a surface treatment layer is disposed on at least one surface of the substrate layer. The surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by a mixture of polymer and inorganic materials. For example, the inorganic layer includes inorganic particles and a binder. The inorganic particles are not particularly limited and may be selected from at least one of alumina, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, or barium sulfate. The binder is not particularly limited and may be selected from at least one of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, or polyhexafluoropropylene. The polymer layer contains a polymer, and the polymer material includes at least one of polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride, or poly(vinylidene fluoride-hexafluoropropylene).

[0055] The electrochemical device of this application may also include a packaging bag. This application does not have any particular restrictions on the packaging bag, and it can be a packaging bag known in the art, as long as it can achieve the purpose of this application. For example, aluminum-plastic film or steel shell.

[0056] This application does not impose any particular limitation on the type of electrochemical device, which may include any device in which an electrochemical reaction occurs. For example, electrochemical devices may include, but are not limited to: lithium metal secondary batteries, lithium-ion secondary batteries, sodium-ion secondary batteries, lithium polymer secondary batteries, and lithium-ion polymer secondary batteries.

[0057] This application does not impose any particular limitation on the preparation method of the electrochemical device. Any preparation method known in the art can be used, as long as it achieves the purpose of this application. For example, the preparation method of the electrochemical device includes, but is not limited to, the following steps: stacking the positive electrode, separator, and negative electrode in sequence, and performing operations such as winding and folding as needed to obtain a wound electrode assembly; placing the electrode assembly in a packaging bag; injecting electrolyte into the packaging bag and sealing it to obtain the electrochemical device; or, stacking the positive electrode, separator, and negative electrode in sequence, then fixing the four corners of the entire stacked structure to obtain a stacked electrode assembly; placing the electrode assembly in a packaging bag; injecting electrolyte into the packaging bag and sealing it to obtain the electrochemical device.

[0058] A second aspect of this application provides an electronic device comprising the electrochemical device described in any of the foregoing embodiments. Therefore, the electronic device exhibits good performance in use.

[0059] The electronic devices covered by this application are not particularly limited and may include, but are not limited to: laptops, pen-based computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, etc.

[0060] Example

[0061] The embodiments and comparative examples provided below illustrate the implementation of this application in more detail. Various tests and evaluations were conducted according to the methods described below.

[0062] Test methods and equipment:

[0063] Inorganic solid electrolytes, electrolyte composition and content testing:

[0064] The negative electrode sheet was obtained by disassembling a lithium-ion battery (0% state of charge, 2.5V). After cleaning the negative electrode sheet with dimethyl carbonate (DMC), the structure type of the inorganic solid electrolyte in the negative electrode material layer on the surface of the negative electrode sheet was tested by X-ray diffraction (XRD), and the composition of the inorganic solid electrolyte was tested by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS).

[0065] The electrolyte was obtained by disassembling a lithium-ion battery (0% state of charge, 2.5V). The mass percentage of organic solvent, compound (I), polymer monomer, initiator, and unsaturated bond additive in the electrolyte was determined by gas chromatography-mass spectrometry (GCMS). The mass percentage of lithium salt was determined by ion chromatography-mass spectrometry.

[0066] Cyclic performance test:

[0067] Three lithium-ion batteries from the examples or comparative examples were placed in a 25°C environment and left to stand for 30 minutes. The following three charge-discharge cycles were then tested: ① Charged at 0.5C to 4.2V, then constant-voltage charged to 0.05C, and finally constant-current discharged at 0.5C to 2.8V; ② Charged at 0.5C to 4.25V, then constant-voltage charged to 0.05C, and finally constant-current discharged at 0.5C to 2.5V; ③ Charged at 0.5C to 4.25V, then constant-voltage charged to 0.05C, and finally constant-current discharged at 1C to 2.5V. The initial discharge capacity C1 and the discharge capacity C1' after each cycle were recorded. The capacity retention rate η = (C1' / C1) × 100%. When η = 70%, the number of cycles ε corresponding to C1' was recorded. The test results using process ① are recorded as 2.8V-4.2Vε1, those using process ② are recorded as 2.5V-4.25Vε2, and those using process ③ are recorded as 2.5V-4.25Vε3. The cycle performance of lithium-ion batteries is evaluated by the number of cycles; a higher number of cycles indicates better cycle performance, and vice versa.

[0068] Example 1-1

[0069] <Preparation of Electrolyte>

[0070] In an argon-atmospheric glove box with a water content of less than 10 ppm, organic solvents were mixed uniformly at a mass ratio of EC:PC:DEC = 1:2:7. Lithium salts LiPF6 and LiFSI were then added, dissolved, and mixed uniformly to obtain the basic electrolyte. Compound (I) of formula (I-2), the monomers ethylene oxide and ethylene glycol diacrylate were added to the basic electrolyte and mixed uniformly to obtain the final electrolyte.

[0071] Based on the mass of the electrolyte, the mass percentage of LiPF6 is 8%, the mass percentage of LiFSI is 8%, the mass percentage of compound (I) is m% = 0.01%, the mass percentage of polymeric monomer is n% = 0.3% (ethylene oxide and ethylene glycol diacrylate are 0.2% and 0.1% respectively), and the remainder is organic solvent. The sum of the mass percentages of organic solvent, lithium salt, compound (I) and polymeric monomer is 100%.

[0072] <Preparation of the positive electrode>

[0073] The positive electrode active material Ni88(Li[Ni 0.88 Co 0.02 Mn 0.1 O2), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) binder were mixed in a mass ratio of 98:1:1. N-methylpyrrolidone (NMP) was added as a solvent, and the mixture was stirred under vacuum until a homogeneous positive electrode slurry with a solid content of 75 wt% was obtained. The positive electrode slurry was uniformly coated onto one surface of a 10 μm thick aluminum foil for positive electrode current collectors and dried at 85°C for 4 hours to obtain a positive electrode sheet with a single-sided coating of positive electrode active material layer (110 μm thick). The above steps were then repeated on the other surface of the aluminum foil to obtain a positive electrode sheet with a double-sided coating of positive electrode active material layer. After cold pressing, cutting, and slitting, the sheet was dried under vacuum at 85°C for 4 hours to obtain a positive electrode sheet with a size of 74 mm × 851 mm for later use.

[0074] <Preparation of Negative Electrode Sheets>

[0075] The negative electrode active material SiO, conductive agent conductive carbon black (Super P), binder styrene-butadiene rubber (SBR, solid content 45 wt%), and stabilizer sodium carboxymethyl cellulose (CMC-Na, weight average molecular weight 400,000) were mixed in a mass ratio of 86:2:2:10. Deionized water was then added as a solvent, and the mixture was stirred under vacuum until a homogeneous negative electrode slurry with a solid content of 53 wt% was obtained. The negative electrode slurry was uniformly coated onto one surface of an 8 μm thick copper foil current collector and dried at 85°C to obtain a negative electrode sheet with a single-sided coating of the negative electrode active material layer (130 μm thick). The above steps were then repeated on the other surface of the copper foil to obtain a negative electrode sheet with a double-sided coating of the negative electrode active material layer. After cold pressing, cutting, and slitting, the sheet was dried under vacuum at 120°C for 12 hours to obtain a negative electrode sheet with dimensions of 76 mm × 867 mm for later use.

[0076] <Septum>

[0077] A polyethylene film with a thickness of 12μm is used.

[0078] <Preparation of Lithium-ion Batteries>

[0079] The negative electrode sheet, separator, and positive electrode sheet prepared above are stacked and wound in sequence to obtain a wound electrode assembly. The electrode assembly is placed in an aluminum-plastic film packaging bag, dried, and then injected with electrolyte. After vacuum sealing, standing at 60°C for 12 hours, formation (0.1C constant current charging to 3.5V, then 0.5C constant current charging to 3.9V), degassing, and edge trimming, a lithium-ion battery is obtained.

[0080] Examples 1-2 to Examples 1-10

[0081] Except for adjusting the relevant preparation parameters according to Table 1, the rest is the same as in Example 1-1.

[0082] In Examples 1-2 to 1-10, when the mass percentage of compound (I) changes, the mass percentage of organic solvent changes accordingly, while the mass percentage of other components remains unchanged. The sum of the mass percentages of organic solvent, lithium salt, compound (I), and polymer monomer is 100%.

[0083] Examples 1-11 to Examples 1-15

[0084] Except for adjusting the relevant preparation parameters according to Table 1, the rest is the same as in Examples 1-3.

[0085] Examples 1-16 to Examples 1-23

[0086] Except for adjusting the relevant preparation parameters according to Table 1, the rest is the same as in Examples 1-3.

[0087] In Examples 1-16 to 1-23, when the mass percentage of the polymeric monomer changes, the mass percentage of the organic solvent changes accordingly, while the mass percentage of the other components remains unchanged. The sum of the mass percentages of the organic solvent, lithium salt, compound (I), and polymeric monomer is 100%.

[0088] Examples 1-24 to Examples 1-25

[0089] Except for adjusting the relevant preparation parameters according to Table 1, the rest is the same as in Examples 1-3.

[0090] In Examples 1-24 and 1-25, when the mass percentage of the compound of formula (I) and / or the mass percentage of the polymer monomer changes, the mass percentage of the organic solvent changes accordingly, while the mass percentage of the other components remains unchanged. The sum of the mass percentages of the organic solvent, lithium salt, compound of formula (I), and polymer monomer is 100%.

[0091] Example 2-1

[0092] <Preparation of the positive electrode>

[0093] The positive electrode active material Ni88(Li[Ni 0.88 Co 0.02 Mn 0.1 O2), inorganic solid electrolyte Li 1.7 Al 0.7 Ti 1.3(PO4)3, conductive carbon black (Super P) as a conductive agent, and polyvinylidene fluoride (PVDF) as a binder are mixed in a mass ratio of 97.995:0.005:1:1. N-methylpyrrolidone (NMP) is added as a solvent, and the mixture is stirred under vacuum until a homogeneous positive electrode slurry with a solid content of 75 wt% is obtained. The positive electrode slurry is uniformly coated onto one surface of a 10 μm thick aluminum foil for positive electrode current collectors and dried at 85°C for 4 hours to obtain a positive electrode sheet with a single-sided coating of positive electrode active material layer (110 μm thick). The above steps are then repeated on the other surface of the aluminum foil to obtain a positive electrode sheet with a double-sided coating of positive electrode active material layer. After cold pressing, cutting, and slitting, the sheet is dried under vacuum at 85°C for 4 hours to obtain a positive electrode sheet with a size of 74 mm × 867 mm for later use.

[0094] The rest is the same as in Examples 1-22.

[0095] Examples 2-2 to 2-7

[0096] Except for adjusting the relevant preparation parameters according to Table 2, the rest is the same as in Example 2-1.

[0097] In the <Preparation of Positive Electrode Sheets> of Examples 2-2 to 2-7, when the mass percentage θ of the inorganic solid electrolyte changes, the mass percentage of the positive electrode active material changes accordingly, while the contents of the other components remain unchanged. The sum of the mass percentages of the positive electrode active material, inorganic solid electrolyte, conductive agent, binder, and stabilizer is 100%.

[0098] In the <Preparation of Electrolyte> of Examples 2-2 to 2-7, when the mass percentage of the polymeric monomer changes, the mass percentage of the organic solvent changes accordingly, while the mass percentage of the other components remains unchanged. The sum of the mass percentages of the organic solvent, lithium salt, compound (I), and polymeric monomer is 100%.

[0099] Examples 2-8 to 2-9

[0100] In the <Preparation of Electrolyte>, except that the mass percentage of the polymer monomer is adjusted and the mass percentage of the organic solvent changes accordingly, while the mass percentage of the other components remains unchanged, everything else is the same as in Examples 1-5.

[0101] Except for the section on "Preparation of Positive Electrode Sheet," where the mass percentage of the inorganic solid electrolyte is adjusted and the mass percentage of the positive electrode active material changes accordingly, the mass percentages of the other components remain unchanged, the process is the same as in Example 2-1.

[0102] Example 2-10

[0103] In the <Preparation of Electrolyte>, except that the mass percentage of the polymeric monomer is adjusted and the mass percentage of the organic solvent changes accordingly, while the mass percentage of the other components remains unchanged, everything else is the same as in Examples 1-22.

[0104] The rest, except for the section on "Preparation of Positive Electrode," which describes the use of inorganic solid electrolyte Li... 1.7 Al 0.7 Ti 1.3 (PO4)3 is replaced with Li 1.5 Al 0.5 Ge 1.5 (PO4)3, by adjusting the mass percentage of the inorganic solid electrolyte, the mass percentage of the positive electrode active material changes accordingly, while the mass percentage of the other components remains unchanged, which is the same as in Examples 2-8.

[0105] Example 3-1

[0106] Except for the addition of the initiator azobisisobutyronitrile in the <Preparation of Electrolyte> (as shown in Table 3), the mass percentage of organic solvent is reduced accordingly, and the mass percentages of compound (I), lithium salt, and polymer monomer remain unchanged, the rest is the same as in Examples 2-10.

[0107] Examples 3-2 to 3-6

[0108] Except for adjusting the mass percentage of the initiator (y%) according to Table 3, and reducing the mass percentage of the organic solvent accordingly, while keeping the mass percentages of the compound of formula (I), lithium salt, and polymer monomer unchanged, the rest is the same as in Example 3-1.

[0109] Examples 3-7

[0110] Except for the addition of the initiator azobisisobutyronitrile in the amount shown in Table 3 in the <Preparation of Electrolyte>, the mass percentage of organic solvent is reduced accordingly, and the mass percentages of compound (I), lithium salt, and polymer monomer remain unchanged, the rest are the same as in Examples 2-9.

[0111] Examples 3-8

[0112] Except for adjusting the relevant preparation parameters according to Table 3, the rest is the same as in Examples 3-7.

[0113] Examples 3-9

[0114] Except for the addition of the additive 3-hexenedicyanate containing unsaturated bonds in the content of Table 3 in the <Preparation of Electrolyte>, the mass percentage of organic solvent is reduced accordingly, and the mass percentage of compound (I), lithium salt and polymer monomer remains unchanged, the rest is the same as in Examples 2-10.

[0115] Examples 3-10 to 3-13

[0116] Except for adjusting the type and mass percentage h% of additives containing unsaturated bonds according to Table 3, reducing the mass percentage of organic solvents accordingly, and keeping the mass percentages of compound (I), lithium salt, and polymer monomers unchanged, the rest are the same as in Examples 3-9.

[0117] Examples 3-14 to 3-16

[0118] Except for the addition of unsaturated bond-containing additives of the amounts and types listed in Table 3 in the <Preparation of Electrolyte>, the mass percentage of organic solvent is reduced accordingly, and the mass percentages of compound (I), lithium salt, polymerizing monomer, and initiator remain unchanged, the rest is the same as in Examples 3-4.

[0119] Example 3-17

[0120] Except for the addition of initiators of the contents and types listed in Table 3, additives containing unsaturated bonds of the contents and types listed in Table 3 in the <Preparation of Electrolyte>, the mass percentage of organic solvent is reduced accordingly, and the mass percentage of compound (I), lithium salt, polymer monomer and initiator remains unchanged, the rest is the same as in Examples 3-14.

[0121] Comparative Examples 1 to 8

[0122] Except for adjusting the relevant preparation parameters according to Table 1, the rest is the same as in Example 1-1.

[0123] In Comparative Examples 1 to 8, when the mass percentage of compound (I) and / or the mass percentage of polymeric monomer changed, the mass percentage of organic solvent changed accordingly, while the mass percentage of other components remained unchanged. The sum of the mass percentages of organic solvent, lithium salt, compound (I), and polymeric monomer was 100%.

[0124] The preparation and performance parameters of each embodiment and comparative example are shown in Tables 1 to 3.

[0125] Table 1

[0126]

[0127]

[0128] Note: In Table 1, "\" indicates that there is no corresponding parameter.

[0129] As can be seen from Examples 1-1 to 1-25 and Comparative Examples 1 to 8, the electrolytes used in the embodiments of this application simultaneously contain the compound of formula (I) and the polymeric monomer of this application, and the mass percentage content of the compound of formula (I) and the polymeric monomer is within the range of this application. The electrolyte of Comparative Example 1 did not contain the compound of formula (I) and the polymeric monomer of this application; the electrolytes of Comparative Examples 2 and 3 contained the polymeric monomer of this application but not the compound of formula (I); the electrolytes of Comparative Examples 4 and 5 contained the compound of formula (I) of this application but not the polymeric monomer of this application; the electrolytes of Comparative Examples 6 and 7 simultaneously contained the compound of formula (I) and the polymeric monomer of this application, but the mass percentage content of the polymeric monomer was not within the range of this application; the electrolyte of Comparative Example 8 simultaneously contained the compound of formula (I) and the polymeric monomer of this application, but the mass percentage content of the compound of formula (I) was not within the range of this application. The lithium-ion batteries in this embodiment exhibit high cycle counts in all three stages of the cycle performance test (processes ① to ③); however, the lithium-ion batteries in the comparative examples do not consistently show high cycle counts in all three stages. This indicates that the lithium-ion batteries in this embodiment have better cycle performance at high voltage and high discharge rate. Therefore, using the electrolyte provided in this application, the resulting lithium-ion batteries exhibit better cycle performance at high voltage and high discharge rate.

[0130] The mass percentage m% of the compound of formula (I) typically affects the cycle performance of lithium-ion batteries at high voltage and high discharge rate. As can be seen from Examples 1-1 to 1-10 and Comparative Example 8, lithium-ion batteries using a mass percentage m% of the compound of formula (I) within the scope of this application exhibit high cycle counts in the cycle performance tests of processes ① to ③, indicating that the lithium-ion batteries have good cycle performance at high voltage and high discharge rate.

[0131] The type of compound in formula (I) typically affects the cycle performance of lithium-ion batteries at high voltage and high discharge rate. As can be seen from Examples 1-3, 1-8, 1-11 to 1-15, lithium-ion batteries using compounds of formula (I) within the scope of this application exhibit high cycle counts in the cycle performance tests of processes ① to ③, indicating that the lithium-ion batteries have good cycle performance at high voltage and high discharge rate.

[0132] The mass percentage (n%) of the polymer monomers typically affects the cycle performance of lithium-ion batteries at high voltages and high discharge rates. As can be seen from Examples 1-16 to 1-21, Comparative Examples 6 and 7, lithium-ion batteries using polymer monomers with a mass percentage (n%) within the scope of this application exhibit high cycle counts in cycle performance tests from process ① to process ③, indicating that the lithium-ion batteries have good cycle performance at high voltages and high discharge rates.

[0133] The type of polymer monomer typically affects the cycle performance of lithium-ion batteries at high voltage and high discharge rate. As can be seen from Examples 1-3, 1-18, and 1-22, lithium-ion batteries using polymer monomers selected within the scope of this application exhibit high cycle counts in cycle performance tests from process ① to process ③, indicating that the lithium-ion batteries have good cycle performance at high voltage and high discharge rate.

[0134] (n / M 单 ) / (m / M (I) The value of (n / M) also typically affects the cycle performance of lithium-ion batteries at high voltage and high discharge rate. As can be seen from Examples 1-1 to 1-25, selecting (n / M) 单 ) / (m / M (I) The value of the lithium-ion battery within the scope of this application shows that it has a high number of cycles in the cycle performance tests of processes ① to ③, indicating that the lithium-ion battery has good cycle performance under high voltage and high discharge rate.

[0135] Table 2

[0136]

[0137]

[0138] Note: In Table 2, "\" indicates that there is no corresponding parameter.

[0139] As can be seen from Examples 1-22, 2-1 to 2-10, adding an inorganic solid electrolyte to the positive electrode material layer, the inorganic solid electrolyte and the electrolyte containing the compound of formula (I) and the polymer monomer work synergistically to further improve the cycle performance of lithium-ion batteries under high voltage and high discharge rate.

[0140] The mass percentage θ% of the inorganic solid electrolyte typically affects the cycle performance of lithium-ion batteries at high voltages and high discharge rates. As can be seen from Examples 1-22 and Examples 2-1 to 2-7, lithium-ion batteries using an inorganic solid electrolyte mass percentage θ% within the scope of this application exhibit high cycle counts in the cycle performance tests of processes ① to ③, indicating that the lithium-ion batteries have good cycle performance at high voltages and high discharge rates.

[0141] The value of n / θ typically affects the cycle performance of lithium-ion batteries under high voltage and high discharge rate. As can be seen from Examples 2-1 to 2-10, lithium-ion batteries using the selected n / θ value within the scope of this application exhibit high cycle counts in the cycle performance tests of processes ① to ③, indicating that the lithium-ion batteries have good cycle performance under high voltage and high discharge rate.

[0142] The type of inorganic solid electrolyte typically affects the cycle performance of lithium-ion batteries at high voltages and high discharge rates. As can be seen from Examples 2-1 to 2-10, lithium-ion batteries using inorganic solid electrolytes within the scope of this application exhibit high cycle counts in the cycle performance tests of processes ① to ③, indicating that the lithium-ion batteries have good cycle performance at high voltages and high discharge rates.

[0143] Table 3

[0144]

[0145]

[0146] Note: "\" in Table 3 indicates no corresponding parameter; "y(%)" in Table 3 indicates the mass percentage of initiator based on the mass of electrolyte; "h(%)" in Table 3 indicates the mass percentage of additives containing unsaturated bonds based on the mass of electrolyte.

[0147] As can be seen from Examples 2-9, 2-10, 3-1 to 3-8, when an initiator is further added to the electrolyte, and the polymerization of the monomers in the electrolyte is initiated by the initiator, the cycle performance of the lithium-ion battery under high voltage and high discharge rate is further improved.

[0148] The mass percentage (y%) of the initiator also typically affects the cycle performance of lithium-ion batteries at high voltage and high discharge rate. As can be seen from Examples 2-10, 3-1 to 3-6, 2-9, and 3-7, lithium-ion batteries using an initiator mass percentage (y%) within the scope of this application exhibit high cycle counts in the cycle performance tests of processes ① to ③, indicating that the lithium-ion batteries have good cycle performance at high voltage and high discharge rate.

[0149] The type of initiator also typically affects the cycle performance of lithium-ion batteries at high voltages and high discharge rates. As can be seen from Examples 3-7 and 3-8, the lithium-ion batteries using the selected initiator within the scope of this application exhibit high cycle counts in the cycle performance tests of processes ① to ③, indicating that the lithium-ion batteries have good cycle performance at high voltages and high discharge rates.

[0150] As can be seen from Examples 2-10, 3-9 to 3-13, the addition of additives containing unsaturated bonds to the electrolyte further improves the cycle performance of lithium-ion batteries under high voltage and high discharge rate.

[0151] The mass percentage (h%) and type of additives containing unsaturated bonds typically affect the cycle performance of lithium-ion batteries at high voltage and high discharge rate. As can be seen from Examples 2-10, 3-9 to 3-13, lithium-ion batteries using additives containing unsaturated bonds with a mass percentage (h%) and type within the scope of this application exhibit high cycle counts in the cycle performance tests of processes ① to ③, indicating that the lithium-ion batteries have good cycle performance at high voltage and high discharge rate.

[0152] As can be seen from Examples 2-10, 3-4, 3-9, 3-14 to 3-17, when an initiator and an additive containing unsaturated bonds are added to the electrolyte simultaneously, the lithium-ion battery exhibits a high number of cycles in the cycle performance tests of processes ① to ③, indicating that the lithium-ion battery has good cycle performance under high voltage and high discharge rate.

[0153] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0154] The various embodiments in this specification are described in a related manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0155] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An electrochemical device comprising an electrolyte, said electrolyte comprising a compound of formula (I) and a polymeric monomer: in, X1 and X2 are each independently selected from Ra-substituted or unsubstituted C2 to C5 heterocyclic groups and Ra-substituted or unsubstituted C6 to C9 aryl groups, wherein the heteroatom in the heterocyclic group is selected from at least one of N, O or S; The substituents Ra of each group are independently selected from C1 to C2 groups that are Rb-substituted or unsubstituted. 12 Alkyl, Rb-substituted or unsubstituted C2 to C3 12 Alkenyl, Rb-substituted or unsubstituted C2 to C5 heterocyclic groups, Rb-substituted or unsubstituted C6 to C5 heterocyclic groups 12 Aryl; The substituents Rb of each group are independently selected from C1 to C6 alkyl, C2 to C6 alkenyl, C6 to C6 alkyl, C2 to C6 alkenyl, C6 to C6 alkenyl, C2 ... 12 aryl, C1 to C6 alkoxy, C6 to C 12 At least one of the following: aryloxy, C1 to C6 ester, Si1 to Si6 silyl, Si1 to Si6 siloxane, amino, ether, carbonyl, carboxyl, sulfonic acid, mercapto, nitro, cyano, or halogen; The polymer monomers include at least one selected from methyl acrylate, methyl methacrylate, vinylene carbonate, ethylene carbonate, ethylene, propylene, vinyl acetate, difluoroethylene, tetrafluoroethylene, hexafluoropropylene, acrylonitrile, ethylene glycol, ethylene glycol diacrylate, diethylene glycol diacrylate, ethylene oxide, dioxolane, 2,6-dimethylphenol, 3,4-ethylenedioxothiophene, or 4,6-diamino-1,3-m-diphenol. Based on the mass of the electrolyte, the mass percentage of the compound of formula (I) is m%, 0.01≤m≤5, and the mass percentage of the polymeric monomer is n%, 0.5≤n≤10.

2. The electrochemical device according to claim 1, wherein, 0.5≤m≤4, and / or 2≤n≤8.

3. The electrochemical device according to claim 1, wherein, The compound of formula (I) includes at least one of the following compounds: (I-1) to (I-10):

4. The electrochemical device according to claim 1, wherein, The molar mass of the compound of formula (I) is M. (I) g / mol, the molar mass of the polymeric monomer is M 单 g / mol, m, n, M (I) and M 单 The condition is satisfied that: 1.5 ≤ (n / M) 单 ) / (m / M (I) )≤100.

5. The electrochemical device according to claim 1, wherein, The molar mass of the compound of formula (I) is M. (I) g / mol, the molar mass of the polymeric monomer is M 单 g / mol, m, n, M (I) and M 单 The condition is satisfied that: 4.8 ≤ (n / M) 单 ) / (m / M (I) )≤60.

6. The electrochemical device according to claim 1, wherein, The electrochemical device includes a positive electrode sheet, the positive electrode sheet includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector, the positive electrode material layer includes a positive electrode active material and an inorganic solid electrolyte; Based on the mass of the positive electrode material layer, the mass percentage of the inorganic solid electrolyte is θ%, 0.005≤θ≤6.

7. The electrochemical device according to claim 6, wherein, 0.1≤n / θ≤100.

8. The electrochemical device according to claim 6, wherein, 0.005≤θ≤5, and / or 0.5≤n / θ≤100.

9. The electrochemical device according to claim 6, wherein, The inorganic solid electrolyte is a NASICON structural material; The inorganic solid electrolyte includes Li 1+a Al a Ge 2-a (PO4)3, Li 1+a Al a Ge 2-a (PO4)3 heteroatom doped compounds, Li 1+b Al b Ti 2-b (PO4)3, Li 1+b Al b Ti 2-b (PO4)3 heteroatom doped compounds or Li 6.5 La3Zr 1.5 Ta 0.5 O 12 At least one of the following: wherein 0 ≤ a ≤ 0.75, 0 ≤ b ≤ 0.5, and each heteroatom is independently selected from at least one of Y, Ga, Cr, In, Se, Zr, Sn, Fe, V, Hf, Mg, Nb, Sr, and Pr.

10. The electrochemical device according to claim 1, wherein, The electrolyte also includes an initiator, which includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, or methyl ethyl ketone peroxide. Based on the mass of the electrolyte, the initiator has a mass percentage content of 0.001% to 2%.

11. The electrochemical device according to claim 1, wherein, The electrolyte also includes additives containing unsaturated bonds, which include at least one of fluoroethylene carbonate, vinylene carbonate, ethylene ethylene carbonate, 1,3-propenesulfonate lactone, 1,3-propanesulfonate lactone, 3-hexenedicyano, fumaric anhydride or triallylmethoxysilane. Based on the mass of the electrolyte, the mass percentage of the additive containing unsaturated bonds is from 0.01% to 30%.

12. The electrochemical device according to claim 6, wherein, The positive electrode active material comprises LiCoO₂, LiNiO₂, LiMnO₂, LiNi 0.5 Mn 1.5 O₄, LiNi x Co 1-x O₂, LiNi x Co y Mn 1-x-y O₂, LiNi x Co y Al 1-x-y O₂ and modified compounds thereof, wherein 0<x<1, 0<y<1, 0<x+y<1, and x and y in each compound are the same or different.

13. The electrochemical device according to claim 1, wherein, The electrolyte further includes an organic solvent, which includes at least one of carbonate, carboxylic acid ester or ether; The carbonate includes at least one of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, propylene carbonate, ethylene carbonate, dipropyl carbonate, methyl propyl carbonate, fluoroethylene carbonate, difluoroethylene carbonate, pentafluoropropyl ethylene carbonate, methyl trifluoroethyl carbonate, trifluoromethyl ethylene carbonate, or bis(2,2,2-trifluoroethyl) carbonate, and the carboxylic acid ester includes propyl propionate, ethyl propionate, ethyl acetate, ethyl formate, methyl acetate, methyl propionate, propyl acetate, butyl butyrate, ethyl difluoroacetate, and difluoroethyl acetate. The ether comprises at least one of ethyl acetate, ethyl trifluoroacetate, trifluoroethyl acetate, or methyl trifluoropropionate, wherein the ether comprises at least one of 1,3-dioxane, 1,4-dioxane, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol formate ethyl ether, diethoxymethane, 1,3-dimethoxypropane, 1,1,3,3-tetraethoxypropane ether, or 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether; Based on the mass of the electrolyte, the carbonate content is 20% to 80% by mass, the carboxylic acid ester content is 0% to 60% by mass, and the ether content is 0% to 40% by mass.

14. The electrochemical device according to claim 1, wherein, The electrolyte further includes lithium salts, which include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium tetraphenylborate, lithium methanesulfonate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, lithium tris(trifluoromethanesulfonyl)methyl lithium, lithium hexafluorosilicate, lithium dioxalateborate, or lithium difluorooxalateborate. Based on the mass of the electrolyte, the lithium salt has a mass percentage content of 6% to 20%.

15. An electronic device comprising the electrochemical device according to any one of claims 1 to 14.

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