WO2023184159A1 - 电化学装置 - Google Patents

电化学装置 Download PDF

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Publication number
WO2023184159A1
WO2023184159A1 PCT/CN2022/083729 CN2022083729W WO2023184159A1 WO 2023184159 A1 WO2023184159 A1 WO 2023184159A1 CN 2022083729 W CN2022083729 W CN 2022083729W WO 2023184159 A1 WO2023184159 A1 WO 2023184159A1
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Prior art keywords
dielectric
solid electrolyte
modification layer
electric field
negative electrode
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PCT/CN2022/083729
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English (en)
French (fr)
Inventor
关文浩
陈茂华
谢远森
鲁宇浩
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宁德新能源科技有限公司
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Priority to PCT/CN2022/083729 priority Critical patent/WO2023184159A1/zh
Priority to CN202280051826.3A priority patent/CN117693846A/zh
Publication of WO2023184159A1 publication Critical patent/WO2023184159A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof

Definitions

  • This application relates to the field of energy storage, specifically electrochemical devices.
  • Lithium-ion batteries have the advantages of large specific energy, high operating voltage, low self-discharge rate, small size, and light weight, and are widely used in the field of consumer electronics. With the rapid development of electric vehicles and mobile electronic devices, people have higher and higher demands for battery energy density, safety, cycle performance and other related requirements. Most common lithium-ion batteries use organic liquid electrolytes. Under certain usage conditions, such as overcharging or short-circuiting inside the lithium-ion battery, the internal temperature of the battery will rise, which in turn will aggravate the side reactions between the liquid electrolyte and the electrodes. , it is extremely easy for safety accidents to occur.
  • liquid range of liquid electrolytes is generally small, which results in a narrow operating temperature range for lithium-ion batteries using liquid electrolytes, and the ionic conductivity of liquid electrolytes drops significantly at low temperatures, which reduces the cycle performance of lithium-ion batteries.
  • the use of solid electrolytes can fundamentally avoid liquid electrolyte leakage, as well as side reactions, corrosion and other problems caused by liquid electrolytes, ensuring the safety of lithium-ion batteries during the battery's service life.
  • the electrodes and electrolytes in all-solid-state lithium-ion batteries are both solid, the interface contact between the two heterogeneous solids is much weaker than the liquid-solid contact interface, which brings about the problem of hindered diffusion of lithium ions on the solid-solid interface.
  • the present application provides an electrochemical device having a dielectric modification layer located between the negative electrode and the solid electrolyte.
  • the dielectric modification layer can improve the interface between the electrode and the solid electrolyte. contact, thereby effectively improving the cycle performance of the electrochemical device.
  • the present invention provides an electrochemical device, which includes a positive electrode, a negative electrode, a solid electrolyte and a dielectric modification layer.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte, wherein the dielectric modification layer There is a built-in electric field inside, and the direction of the built-in electric field is from the positive electrode to the negative electrode.
  • the dielectric modification layer is a powder coating or film with a ferroelectric effect or a piezoelectric effect.
  • An ordered polarization electric field is formed inside the dielectric modification layer from the positive electrode to the negative electrode, so that the surface of the negative electrode is in contact with the dielectric
  • the electrically modified layer contacts the negatively charged terminals.
  • the built-in electric field of the dielectric modification layer will promote the rapid transmission of lithium ions to the anode surface, improving the lithium ion transmission dynamics at the solid-solid interface; in addition, the dielectric modification layer is used to The dielectric effect provides negative feedback to the lithium ion flow at the solid-solid interface, which can suppress the generation of large currents at the solid-solid interface and achieve uniformity of the current; the uniformly covered dielectric modification layer can avoid the interaction between the solid electrolyte and the electrode.
  • the soft and elastic dielectric modification layer can also improve the physical contact at the interface between the solid electrolyte and the electrode, reduce the interface impedance, thereby improving Cycling performance of electrochemical devices.
  • the dielectric modification layer covers the surface of the solid electrolyte, that is, is between the negative electrode and the solid electrolyte, or covers the surface of the negative active material layer.
  • the dielectric modification layer includes a dielectric material
  • the strength of the room temperature coercive field of the dielectric material is Ec, 0 kV/mm ⁇ Ec ⁇ 100kV/mm.
  • Ec can be 0.5kV/mm, 5kV/mm, 10kV/mm, 20kV/mm, 30kV/mm, 40kV/mm, 50kV/mm, 60kV/mm, 70kV/mm, 80kV/mm , 90kV/mm, 100kV/mm and any value between them.
  • the thickness of the dielectric modification layer is L, 100nm ⁇ L ⁇ 5 ⁇ m.
  • L can be 100 nm, 500 nm, 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, and any value therebetween.
  • the dielectric material includes one or more of dielectric polymers, dielectric ceramics, dielectric single crystals, or inorganic dielectric films.
  • the dielectric polymer includes polyvinylidene fluoride (PVDF), polyvinylidene fluoride/polytrifluoroethylene copolymer, polyvinylidene fluoride/polytetrafluoroethylene copolymer, having the formula - (HN -(CH 2 ) x -CO-) n - one or more odd-numbered nylon dielectric polymers or amorphous dielectric polymers, where x is an even number and n is any positive integer.
  • the dielectric ceramic includes one or more of unitary piezoelectric ceramics, binary piezoelectric ceramics or ternary piezoelectric ceramics.
  • the dielectric single crystal includes a dielectric ceramic grown single crystal.
  • the inorganic dielectric film includes one of films or flakes made of metal oxides, nitrides, carbides, intermetallic compounds, dielectric ceramics or dielectric single crystals with piezoelectric properties, or Various.
  • the amorphous dielectric polymer includes vinylidene dicyanide/vinyl acetate copolymer (P(VDCN-VAC)), vinylidene dicyanide/vinyl benzoate copolymer (P(VDCN -VBz)), vinylidene dicyanide/vinyl propionate copolymer (P(VDCN-VPr)), vinylidene dicyanide/vinyl pivalate copolymer (P(VDCN-VPiv)), vinylidene dicyanide/vinyl pivalate copolymer (P(VDCN-VPiv)), One or more of cyanide/methyl methacrylate copolymer (P(VDCN-MMA)) or vinylidene dicyanide/isobutylene copolymer (P(VDCN-IB)).
  • the unit piezoelectric ceramic includes one of barium titanate (BaTiO 3 ), lead titanate (PbTiO 3 ), lithium niobate (LiNbO 3 ) or lithium tantalate (LiTaO 3 ), or Various.
  • the binary system piezoelectric ceramic includes lead zirconate titanate having the formula PbZr x Ti 1-x O 3 , where 0 ⁇ x ⁇ 1.
  • the ternary piezoelectric ceramic includes lead zirconate titanate with the formula PbZr x Ti 1-x O 3 and lead magnesium niobate with the formula PbMg x Nb 1-x O 3 .
  • a mixture of lead niobate zincate with the formula PbMn x Sb 1-x O 3 or lead manganese antimonate with the formula PbMn One or more of Pb 1 -x M x (Zr y Ti 1-y ) 1-(x/4) O 3 formed by lead zirconate titanate of x Ti 1-x O 3 and rare earth elements, where M It is a rare earth metal, such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), etc., 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1.
  • the dielectric single crystal includes quartz single crystal, bismuth germanate single crystal (Bi 12 GeO 20 ), lithium iodate single crystal (LiIO 3 ), aluminum orthophosphate single crystal (AlPO 4 ), silicon
  • LiIO 3 lithium iodate single crystal
  • AlPO 4 aluminum orthophosphate single crystal
  • silicon One or more of lanthanum gallium acid single crystal (La 3 Ga 5 SiO 14 ), barium titanate single crystal (BaTiO 3 ), tellurium oxide single crystal or lead zirconate titanate with the formula PbZr x Ti 1-x O 3 kind, where 0 ⁇ x ⁇ 1.
  • the dielectric modification layer forms a built-in electric field after being polarized in a polarization electric field.
  • the intensity of the polarization electric field is 0.1 to 6 times the room temperature coercive field intensity of the dielectric material. For example, it can It is 0.1 times, 0.2 times, 0.5 times, 1 times, 2 times, 3 times, 4 times, 5 times, 6 times and any value between them.
  • the negative electrode includes a negative electrode active material layer, the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material includes lithium metal, a composite material containing lithium metal, a carbon-based material such as graphite or hard carbon, silicon, One or more of silicon composite or lithium titanate.
  • the solid electrolyte includes one or more of a garnet structure solid electrolyte, a NASICON structure solid electrolyte, an organic polymer solid electrolyte, an anti-perovskite solid electrolyte or a sulfide solid electrolyte.
  • the dielectric modification layer includes a dielectric material
  • the strength of the coercive field at room temperature of the dielectric material is Ec, 1kV/mm ⁇ Ec ⁇ 60kV/mm.
  • Ec can be 1kV/mm, 3kV/mm, 5kV/mm, 8kV/mm, 15kV/mm, 25kV/mm, 35kV/mm, 45kV/mm, 55kV/mm, 60kV/mm, and any value between them.
  • the thickness L of the dielectric modification layer satisfies: 100nm ⁇ L ⁇ 3 ⁇ m.
  • L can be 100 nm, 200 nm, 400 nm, 600 nm, 800 nm, 1 ⁇ m, 1.5 ⁇ m, 2 ⁇ m, 2.5 ⁇ m, 3 ⁇ m, and any value therebetween.
  • the dielectric modification layer forms a built-in electric field after being polarized in a polarization electric field.
  • the intensity of the polarization electric field is 3kV/mm to 100kV/mm, for example, it can be 3kV/mm or 8kV/mm. , 15kV/mm, 25kV/mm, 35kV/mm, 45kV/mm, 55kV/mm, 65kV/mm, 75kV/mm, 85kV/mm, 95kV/mm, 100kV/mm and any value between them.
  • the electrochemical device provided by this application has a dielectric modification layer located between the negative electrode and the solid electrolyte.
  • An ordered polarization electric field is formed inside the dielectric modification layer from the positive electrode to the negative electrode, which can improve the relationship between the electrode and the solid electrolyte.
  • Interfacial contact improves the lithium ion transport dynamics at the anode/electrolyte interface, thereby reducing the interface impedance; the evenly covered dielectric modification layer can also avoid direct contact between the solid electrolyte and the anode, avoiding the occurrence of side reactions, thereby improving electrochemistry Cycling performance of the device.
  • Figure 1 is a schematic structural diagram (cross-sectional view) of a dielectric modification layer according to some embodiments of the present application, in which 1 is a solid electrolyte, 2 is a dielectric modification layer, 3 is an anode active material layer, 4 is a copper foil, and 5 is the built-in electric field of the dielectric modification layer.
  • Figure 2 is a schematic diagram of the polarization principle of the dielectric modification layer according to some embodiments of the present application, in which 6 is the dielectric material before polarization and 7 is the dielectric material after polarization.
  • any lower limit can be combined with any upper limit to form an unexpressed range; and any lower limit can be combined with other lower limits to form an unexpressed range, and likewise any upper limit can be combined with any other upper limit to form an unexpressed range.
  • each individually disclosed point or single value may itself serve as a lower or upper limit in combination with any other point or single value or with other lower or upper limits to form a range not expressly recited.
  • a list of items connected by the terms “at least one of,” “at least one of,” “at least one of,” or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase “at least one of A and B” means only A; only B; or A and B. In another example, if the items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B and C.
  • Item A may contain a single component or multiple components.
  • Item B may contain a single component or multiple components.
  • Item C may contain a single component or multiple components.
  • the invention provides an electrochemical device, which includes a positive electrode, a negative electrode, a solid electrolyte and a dielectric modification layer.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte, wherein the dielectric modification layer has a built-in electric field inside. , the built-in electric field direction is from the positive electrode to the negative electrode.
  • the dielectric modification layer is a powder coating or film with ferroelectric effect or piezoelectric effect.
  • the dielectric modification layer When it is coated on the surface of the solid electrolyte facing the negative electrode side, or evenly covers the surface of the negative electrode, it will It performs directional polarization and forms an ordered polarization electric field from the positive electrode to the negative electrode inside the dielectric modification layer (as shown in Figures 1 and 2), so that the surface of the negative electrode is in contact with the negative charge end of the dielectric modification layer. It can be seen from Figure 2 that before polarization, the electric dipole moments of the dielectric material are randomly arranged and no equivalent electric field is formed.
  • the electric dipole moments of the dielectric material are arranged in the direction of the polarization electric field, and an equivalent electric field is formed. In the same direction as the polarizing electric field.
  • the built-in electric field of the dielectric modification layer will promote the rapid transmission of lithium ions to the negative electrode surface, improving the lithium ion transmission kinetics at the solid-solid interface.
  • the dielectric effect of the dielectric modification layer is used to provide negative feedback to the lithium ion flow at the solid-solid interface, which can suppress the generation of large current at the solid-solid interface and achieve uniformity of the current.
  • the uniformly covered dielectric modification layer can avoid direct contact between the solid electrolyte and the electrode, avoid interdiffusion of elements between the two, and inhibit the occurrence of side reactions.
  • the soft and elastic dielectric modification layer can also improve the physical contact at the interface between the solid electrolyte and the electrode material, reduce the interface impedance and thereby improve the cycle performance of the electrochemical device.
  • the dielectric modification layer includes a dielectric material
  • the strength of the room temperature coercive field of the dielectric material is Ec, 0 kV/mm ⁇ Ec ⁇ 100kV/mm.
  • Ec can be 0.5kV/mm, 5kV/mm, 10kV/mm, 20kV/mm, 30kV/mm, 40kV/mm, 50kV/mm, 60kV/mm, 70kV/mm, 80kV/mm , 90kV/mm, 100kV/mm and any value between them.
  • the thickness of the dielectric modification layer is L, 100nm ⁇ L ⁇ 5 ⁇ m.
  • L can be 100 nm, 500 nm, 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, and any value therebetween.
  • the dielectric material includes one or more of dielectric polymers, dielectric ceramics, dielectric single crystals, or inorganic dielectric films.
  • the dielectric polymer includes polyvinylidene fluoride (PVDF), polyvinylidene fluoride/polytrifluoroethylene copolymer, polyvinylidene fluoride/polytetrafluoroethylene copolymer, having the formula - (HN -(CH 2 ) x -CO-) n - one or more odd-numbered nylon dielectric polymers or amorphous dielectric polymers, where x is an even number and n is any positive integer.
  • the dielectric ceramic includes one or more of unitary piezoelectric ceramics, binary piezoelectric ceramics or ternary piezoelectric ceramics.
  • the dielectric single crystal includes a dielectric ceramic grown single crystal.
  • the inorganic dielectric film includes one of films or flakes made of metal oxides, nitrides, carbides, intermetallic compounds, dielectric ceramics or dielectric single crystals with piezoelectric properties, or Various.
  • the amorphous dielectric polymer includes vinylidene dicyanide/vinyl acetate copolymer (P(VDCN-VAC)), vinylidene dicyanide/vinyl benzoate copolymer (P(VDCN -VBz)), vinylidene dicyanide/vinyl propionate copolymer (P(VDCN-VPr)), vinylidene dicyanide/vinyl pivalate copolymer (P(VDCN-VPiv)), vinylidene dicyanide/vinyl pivalate copolymer (P(VDCN-VPiv)), One or more of cyanide/methyl methacrylate copolymer (P(VDCN-MMA)) or vinylidene dicyanide/isobutylene copolymer (P(VDCN-IB)).
  • the unit piezoelectric ceramic includes one of barium titanate (BaTiO 3 ), lead titanate (PbTiO 3 ), lithium niobate (LiNbO 3 ) or lithium tantalate (LiTaO 3 ), or Various.
  • the binary system piezoelectric ceramic includes lead zirconate titanate having the formula PbZr x Ti 1-x O 3 , where 0 ⁇ x ⁇ 1.
  • the ternary piezoelectric ceramic includes lead zirconate titanate with the formula PbZr x Ti 1-x O 3 and lead magnesium niobate with the formula PbMg x Nb 1-x O 3 .
  • a mixture of lead niobate zincate with the formula PbMn x Sb 1-x O 3 or lead manganese antimonate with the formula PbMn One or more of Pb 1-x M x (Zr y Ti 1-y ) 1-(x/4) O 3 formed by PbZr x Ti 1-x O 3 lead zirconate titanate and rare earth elements, wherein M is a rare earth metal, such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), etc., 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1.
  • La lanthanum
  • Ce cerium
  • Pr praseodymium
  • Nd neodymium
  • the dielectric single crystal includes quartz single crystal, bismuth germanate single crystal (Bi 12 GeO 20 ), lithium iodate single crystal (LiIO 3 ), aluminum orthophosphate single crystal (AlPO 4 ), silicon
  • LiIO 3 lithium iodate single crystal
  • AlPO 4 aluminum orthophosphate single crystal
  • silicon One or more of lanthanum gallium acid single crystal (La 3 Ga 5 SiO 14 ), barium titanate single crystal (BaTiO 3 ), tellurium oxide single crystal or lead zirconate titanate with the formula PbZr x Ti 1-x O 3 kind, where 0 ⁇ x ⁇ 1.
  • the dielectric modification layer forms a built-in electric field after being polarized in a polarization electric field.
  • the intensity of the polarization electric field is 0.1 to 6 times the room temperature coercive field intensity of the dielectric material. For example, it can It is 0.1 times, 0.2 times, 0.5 times, 1 times, 2 times, 3 times, 4 times, 5 times, 6 times and any value between them.
  • the negative electrode includes a negative electrode active material layer, the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material includes lithium metal, a composite material containing lithium metal, a carbon-based material such as graphite or hard carbon, silicon, One or more of silicon composite or lithium titanate.
  • the solid electrolyte includes one or more of a garnet structure solid electrolyte, a NASICON structure solid electrolyte, an organic polymer solid electrolyte, an anti-perovskite solid electrolyte or a sulfide solid electrolyte.
  • the dielectric modification layer includes a dielectric material
  • the strength of the coercive field at room temperature of the dielectric material is Ec, 1kV/mm ⁇ Ec ⁇ 60kV/mm.
  • Ec can be 1kV/mm, 3kV/mm, 5kV/mm, 8kV/mm, 15kV/mm, 25kV/mm, 35kV/mm, 45kV/mm, 55kV/mm, 60kV/mm, and any value between them.
  • the thickness L of the dielectric modification layer satisfies: 100nm ⁇ L ⁇ 3 ⁇ m.
  • L can be 100 nm, 200 nm, 400 nm, 600 nm, 800 nm, 1 ⁇ m, 1.5 ⁇ m, 2 ⁇ m, 2.5 ⁇ m, 3 ⁇ m, and any value therebetween.
  • the dielectric modification layer forms a built-in electric field after being polarized in a polarization electric field.
  • the intensity of the polarization electric field is 3kV/mm to 100kV/mm, for example, it can be 3kV/mm or 8kV/mm. , 15kV/mm, 25kV/mm, 35kV/mm, 45kV/mm, 55kV/mm, 65kV/mm, 75kV/mm, 85kV/mm, 95kV/mm, 100kV/mm and any value between them.
  • Materials, compositions, and methods of manufacturing solid electrolytes that may be used in embodiments of the present application include any techniques disclosed in the prior art.
  • the solid electrolyte includes one or more of a garnet structure solid electrolyte, a NASICON structure solid electrolyte, an organic polymer solid electrolyte, an anti-perovskite solid electrolyte or a sulfide solid electrolyte.
  • the garnet structure solid electrolyte includes Li 7 La 3 Zr 2 O 12 or Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 , etc.
  • non-limiting examples of the NASICON structure solid electrolyte include Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 , etc.
  • Non-limiting examples of organic polymer solid electrolytes include polyethylene oxide (-[-CH 2 ⁇ CH 2 ⁇ O-]- n ) or polyacrylonitrile (C 3 H 3 N) n ), etc.
  • non-limiting examples of sulfide solid electrolytes include Li 6 PS 5 Cl, Li 11 Ge 2 PS 12 etc.
  • the materials, composition, and manufacturing methods of the negative electrode that can be used in embodiments of the present application include any technology disclosed in the prior art.
  • the negative electrode includes a negative electrode active material layer, the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material includes lithium metal, a composite material containing lithium metal, a carbon-based material such as artificial graphite, natural graphite or hard carbon. etc., one or more of silicon and silicon-containing composite materials or lithium titanate.
  • the negative active material layer may include a binder and optionally a conductive material to impart conductivity to the electrode.
  • the binder improves the binding of the negative active material particles to each other and the binding of the negative active material to the current collector.
  • binders include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-containing Oxygen polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin, Nylon etc.
  • the conductive material may include any conductive material as long as it does not cause chemical changes.
  • conductive materials include carbon-based materials (eg, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (eg, metal powder, metal fibers, etc., e.g. copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives) and mixtures thereof.
  • the materials, composition, and manufacturing methods of the cathode that can be used in embodiments of the present application include any technology disclosed in the prior art.
  • the positive electrode includes a positive electrode current collector and a positive electrode active material layer located on the positive electrode current collector.
  • the positive active material includes at least one lithiated intercalation compound that reversibly intercalates and deintercalates lithium ions.
  • the positive active material includes a composite oxide.
  • the composite oxide contains lithium and at least one element selected from cobalt, manganese, and nickel.
  • the cathode active material is selected from lithium cobalt oxide (LiCoO 2 ), lithium nickel cobalt manganese (NCM) ternary material, lithium iron phosphate (LiFePO 4 ), lithium manganate (LiMn 2 O 4 ), or they any combination of.
  • the positive active material layer also includes a binder and optionally a conductive material.
  • the binder improves the binding of the positive active material particles to each other and also improves the binding of the positive active material to the current collector.
  • binders include, but are not limited to: polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-containing Oxygen polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin, Nylon etc.
  • conductive materials include, but are not limited to, carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof.
  • the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, or any combination thereof.
  • the metal-based material is selected from metal powders, metal fibers, copper, nickel, aluminum, silver.
  • the conductive polymer is a polyphenylene derivative.
  • the positive current collector may be aluminum, but is not limited thereto.
  • electrochemical devices of the present application include, but are not limited to: all types of primary batteries, secondary batteries, fuel cells, solar cells or capacitors.
  • the electrochemical device is a lithium secondary battery.
  • lithium secondary batteries include, but are not limited to: lithium metal secondary batteries, lithium ion secondary batteries, lithium polymer secondary batteries, or lithium ion polymer secondary batteries.
  • the present application also provides an electronic device using the electrochemical device according to the present application.
  • electronic devices include, but are not limited to: notebook computers, pen computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headsets, video recorders , LCD TV, portable cleaner, portable CD player, mini CD, transceiver, electronic notepad, calculator, memory card, portable recorder, radio, backup power supply, motor, automobile, motorcycle, power-assisted bicycle, bicycle, lighting Appliances, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries or lithium-ion capacitors, etc.
  • Test thickness with a screw micrometer. Before coating, test and record the thickness of the base material as t1. After coating the dielectric modification layer, test and record the thickness of the dielectric modification layer + base as t2. Then the thickness of the dielectric modification layer is t1-t2.
  • the battery was formed into a circle at a charge rate and discharge rate of 0.1C at 25°C, and then charged to a constant current of 0.3C to 4.3V at a test temperature of 25°C, then charged to a constant voltage of 0.05C, and left to stand. Discharge to 2.8V at 1C after 5 minutes. Use the capacity obtained in this step as the initial capacity, perform a 0.3C charge/1C discharge cycle test, and compare the capacity of each step with the initial capacity to obtain the capacity decay curve. The number of cycles at 25°C until the capacity retention rate reaches 80% is recorded as the room temperature cycle performance of the battery.
  • PVDF-TrFE Disperse vinylidene fluoride/trifluoroethylene copolymer
  • NMP N-methylpyrrolidone
  • the dielectric modified solid electrolyte is dried in a vacuum drying oven at 80°C until use.
  • the thickness of the dielectric modified layer after drying is 1 ⁇ m.
  • the above-mentioned dielectrically modified solid electrolyte is placed in a parallel electric field for polarization.
  • the polarization device includes a positive pressing plate and a negative pressing plate for generating a parallel electric field.
  • the direction of the parallel electric field between the positive pressing plate and the negative pressing plate is directed from the positive voltage plate to the negative direction.
  • Voltage plate, the polarization electric field strength is 10kV/mm, the polarization time is 30min, and the dielectric modification layer faces the positive voltage plate side.
  • ternary cathode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2
  • conductive carbon black Super P
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the lithium metal foil and the negative electrode current collector copper foil are stacked in order and cold-pressed, and then cut into discs with a diameter of 18 mm for later use.
  • the above-mentioned positive electrode sheets, modified solid electrolyte, and negative electrode sheets are stacked in order and then assembled into a button battery.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • step (1) b The only difference from Example 1 is that in step (1) b), the intensity of the polarization electric field is different. See Table 1 for details.
  • Example 1 The only difference from Example 1 is that in a) of step (1), the thickness of the dielectric modification layer is different. See Table 1 for details.
  • the lithium metal foil and the negative electrode current collector copper foil are stacked in order and cold-pressed, and then cut into discs with a diameter of 18 mm for later use.
  • the above-mentioned dielectrically modified negative electrode piece is placed in a parallel electric field for polarization.
  • the polarization electric field is 50kV/mm
  • the polarization time is 30min
  • the dielectrically modified layer faces the negative voltage plate side.
  • dielectrically modified negative electrode sheets Li 10 GeP 2 S 12 solid electrolyte discs with a diameter of 20 mm
  • positive electrode sheets are stacked in sequence and assembled into a button cell.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • Example 9 The only difference from Example 9 is that in a) of step (1), the thickness of the dielectric modification layer is different. See Table 1 for details.
  • Example 9 The only difference from Example 9 is that in b) of step (1), the intensity of the polarization electric field is different. See Table 1 for details.
  • the above dielectrically modified solid electrolyte is placed in a parallel electric field for polarization.
  • the polarization electric field is 50kV/mm
  • the polarization time is 30min
  • the dielectrically modified layer faces the positive voltage plate side.
  • ternary cathode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2
  • conductive carbon black Super P
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the above-mentioned negative electrode plates, dielectric modified solid electrolyte, and positive electrode plates are stacked in sequence and assembled into a button battery.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • the dielectrically modified solid electrolyte is placed in a parallel electric field for polarization.
  • the polarization electric field is 50kV/mm
  • the polarization time is 30min
  • the dielectrically modified layer faces the positive voltage plate side.
  • ternary cathode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2
  • conductive carbon black Super P
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the above-mentioned negative electrode plates, dielectric modified solid electrolyte, and positive electrode plates are stacked in sequence and assembled into a button battery.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • PVDF-TrFE powder Disperse PVDF-TrFE powder in NMP, stir to make PVDF-TrFE disperse evenly, coat it on the surface of Li 10 GeP 2 S 12 solid electrolyte to obtain a dielectrically modified solid electrolyte, and dry it in a vacuum drying oven at 80°C for later use. , the thickness of the dielectric modification layer after drying is 1 ⁇ m.
  • the above dielectrically modified solid electrolyte is placed in a parallel electric field for polarization.
  • the polarization electric field is 50kV/mm
  • the polarization time is 30min
  • the dielectrically modified layer faces the positive voltage plate side.
  • ternary cathode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2
  • Super P conductive carbon black
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the above-mentioned negative electrode plates, dielectric modified solid electrolyte, and positive electrode plates are stacked in sequence and assembled into a button battery.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • Disperse BaTiO 3 powder in NMP stir to disperse the BaTiO 3 powder evenly, coat it on the surface of Li 10 GeP 2 S 12 solid electrolyte to obtain a dielectrically modified solid electrolyte, and dry it in a vacuum drying oven at 80°C until use.
  • the thickness of the dielectric modification layer after drying is 1 ⁇ m.
  • the above-mentioned solid electrolyte is placed in a parallel electric field for polarization.
  • the polarization electric field is 3kV/mm
  • the polarization time is 30 minutes
  • the dielectric modification layer faces the positive voltage plate side.
  • ternary cathode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2
  • conductive carbon black Super P
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the lithium metal foil and the negative electrode current collector copper foil are stacked in order and cold-pressed, and then cut into discs with a diameter of 18 mm for later use.
  • the above-mentioned negative electrode plates, dielectric modified solid electrolyte, and positive electrode plates are stacked in sequence and assembled into a button battery.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • the slurry is evenly coated on the Li 10 GeP 2 S 12 solid
  • the dielectric modified solid electrolyte is obtained on the surface of the electrolyte, which is dried at 80°C in a vacuum drying oven until use.
  • the thickness of the dielectric modified layer after drying is 1 ⁇ m.
  • the above dielectrically modified solid electrolyte is placed in a parallel electric field for polarization.
  • the polarization electric field is 3kV/mm
  • the polarization time is 30min
  • the dielectrically modified layer faces the positive voltage plate side.
  • ternary cathode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2
  • conductive carbon black Super P
  • PVDF polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the lithium metal foil and the negative electrode current collector copper foil are stacked in order and cold-pressed, and then cut into discs with a diameter of 18 mm for later use.
  • the above-mentioned negative electrode plates, dielectric modified solid electrolyte, and positive electrode plates are stacked in sequence and assembled into a button battery.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • the lithium metal foil and the negative electrode current collector copper foil are stacked in order and cold pressed to obtain the negative electrode sheet;
  • a nylon 7 film with a thickness of 5 ⁇ m (brand: Taiwan Chemical Fiber Co., Ltd., brand: NP4000) was placed in a parallel electric field for air polarization.
  • the polarization electric field was 280kV/mm
  • the polarization time was 30 minutes
  • the direction of the polarization electric field was parallel to the film thickness direction and remains constant.
  • the polarized nylon 7 film is attached to the surface of the negative electrode in the negatively charged direction to obtain a dielectric modified negative electrode with a dielectric modification layer thickness of 5 ⁇ m.
  • the dielectric modified negative electrode is cut into a diameter of 18 mm. The disc specifications are ready for use.
  • dielectrically modified negative electrode sheets Li 10 GeP 2 S 12 solid electrolyte discs with a diameter of 20 mm
  • positive electrode sheets are stacked in sequence and assembled into a button cell.
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • the lithium metal foil and the negative electrode current collector copper foil are stacked in order and cold pressed to obtain the negative electrode sheet;
  • a tellurium oxide crystal single chip with a thickness of 5 ⁇ m (brand: Beijing Wuke Optoelectronics Technology Co., Ltd., brand: TEO2) was placed in a parallel electric field for air polarization.
  • the polarization electric field was 3 kV/mm, and the polarization time was 30 minutes.
  • the direction of the electric field is parallel to the thickness direction of the single crystal and remains constant.
  • the polarized tellurium oxide crystal single crystal piece is attached to the surface of the negative electrode piece in the negatively charged direction to obtain a dielectric modified negative electrode piece with a dielectric modification layer thickness of 5 ⁇ m.
  • the negative electrode piece is cut into a circle with a diameter of 18 mm. Tablet specifications are available for later use.
  • the dielectrically modified negative electrode sheet, the Li 10 GeP 2 S 12 solid electrolyte disc with a diameter of 20 mm, and the positive electrode sheet were stacked in sequence and assembled into a button cell. Among them, the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • Example 1 The difference from Example 1 is that the solid electrolyte does not contain a dielectric modification layer, that is, the prepared button battery does not contain a dielectric modification layer. See Table 1 for details.
  • the electrochemical device including the dielectric modification layer provided by the present application that is, the electrochemical device includes a positive electrode, a negative electrode, a solid electrolyte and a dielectric modification layer,
  • the dielectric modification layer is located between the negative electrode and the solid electrolyte.
  • the direction of the built-in electric field is from the positive electrode to the negative electrode. Its cycle performance is significantly better than that of electrochemistry without a dielectric modification layer. device.
  • the built-in electric field in the dielectric modification layer will promote the rapid transmission of lithium ions to the anode surface, which can improve the lithium ion transport dynamics at the solid-solid interface, suppress the generation of large currents at the solid-solid interface, and realize current flow. Homogenize and inhibit the occurrence of side reactions, thereby significantly improving the cycle performance of the electrochemical device.
  • Example 15 to Example 17 it can be seen that for different types of negative electrodes, after polarizing the dielectric modification layer using the polarization electric field intensity and direction within the scope of the present application, the electric power can be effectively improved. Cycling performance of chemical plants.
  • Example 2 Example 5 to Example 7, and Example 8 to Example 11 that the cycle performance of the electrochemical device is better when the thickness of the dielectric modification layer is within the scope of the present application.
  • the room temperature coercive field strength of a dielectric material determines the stability of its built-in electric field.
  • Using a dielectric material modified layer with a coercive field strength within the range of the present application can Further improve the cycle performance of electrochemical devices.

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Abstract

提供一种电化学装置，其包括正极、负极、固态电解质和介电改性层，介电改性层位于负极和固态电解质之间，其中，介电改性层内部具有内建电场，内建电场方向为由正极指向负极。该电化学装置中的介电改性层可以改善电极与固态电解质之间的界面接触，从而有效提升电化学装置的循环性能。

Description

电化学装置 技术领域
本申请涉及储能领域，具体涉及电化学装置。
背景技术
锂离子电池具有比能量大、工作电压高、自放电率低、体积小、重量轻等优势，在消费电子领域具有广泛的应用。随着电动汽车和可移动电子设备的高速发展，人们对电池的能量密度、安全性、循环性能等相关需求越来越高。常见的锂离子电池大多使用有机体系的液态电解质，在特定使用情况下，如锂离子电池内部发生过充或短路时，会导致电池内部温度升高，进而加剧液态电解质与电极之间的副反应，极易发生安全事故。另外，液态电解质的液程一般较小，这导致使用液态电解质的锂离子电池的工作温区比较窄，且低温下液态电解质离子电导率明显下降，使锂离子电池的循环性能等降低。采用固态电解质可以从根本上避免液态电解质漏液，以及液态电解质带来的副反应、腐蚀等问题，在电池服役寿命内保证锂离子电池的安全性。但由于全固态锂离子电池中电极与电解质均为固体，两种异质固体的界面接触远远弱于液-固接触界面，由此带来锂离子在固-固界面上扩散受阻的问题，导致界面阻抗大大增加，使得全固态锂离子电池的性能降低。因此，提升固-固界面接触性质，降低电池内部的界面接触阻抗，是提升全固态锂离子电池性能的关键。
发明内容
为了解决现有技术存在的问题，本申请提供一种电化学装置，其具有位于负极和固态电解质之间的介电改性层，该介电改性层可以改善电极与固态电解质之间的界面接触，从而有效提升电化学装置的循环性能。
为实现上述目的，本发明提供了一种电化学装置，其包括正极、负极、固态电解质和介电改性层，介电改性层位于负极和固态电解质之间，其中，介电改性层内部具有内建电场，内建电场方向为由正极指向负极。本申请中，该介电改性层是具有铁电效应或压电效应的粉末涂层或薄膜，在介电改性层内部形成从正极指向负极的有序极化电场，使负极表面与介电改性层负电荷端接触。当锂离子到达电极/电解质界面处，介电改性层的内建电 场将推动锂离子快速传输到负极表面，提升固-固界面处的锂离子传输动力学；另外，利用介电改性层的介电效应对固-固界面处的锂离子流进行负反馈，可以抑制固-固界面处大电流的产生，实现电流均匀化；均匀覆盖的介电改性层可以避免固态电解质与电极之间的直接接触，避免二者之间的元素互扩散，抑制副反应的发生；柔软且带有弹性的介电改性层还能改善固态电解质与电极的界面物理接触，降低界面阻抗，从而提升电化学装置的循环性能。根据本发明的一些实施方式，介电改性层覆盖在固态电解质表面，即介于负极与固态电解质之间，或者覆盖在负极活性材料层表面。
根据本申请的一些实施方式，介电改性层包括介电材料，介电材料的室温矫顽场的强度为Ec，0kV/mm＜Ec≤100kV/mm。在一些具体实施方式中，Ec可以为0.5kV/mm、5kV/mm、10kV/mm、20kV/mm、30kV/mm、40kV/mm、50kV/mm、60kV/mm、70kV/mm、80kV/mm、90kV/mm、100kV/mm以及它们之间的任意值。
根据本申请的一些实施方式，介电改性层的厚度为L，100nm≤L≤5μm。在一些具体实施方式中，L可以为100nm、500nm、1μm、2μm、3μm、4μm、5μm以及它们之间的任意值。
根据本申请的一些实施方式，介电材料包括介电聚合物、介电陶瓷、介电单晶或无机介电薄膜中的一种或多种。
根据本申请的一些实施方式，介电聚合物包括聚偏氟乙烯(PVDF)、聚偏氟乙烯/聚三氟乙烯共聚物、聚偏氟乙烯/聚四氟乙烯共聚物、具有式-(HN-(CH 2) x-CO-) n-的奇数尼龙系介电聚合物或非晶态介电聚合物中的一种或多种，其中x为偶数，n为任意正整数。根据本申请的一些实施方式，介电陶瓷包括单元系压电陶瓷、二元系压电陶瓷或三元系压电陶瓷中的一种或多种。根据本申请的一些实施方式，介电单晶包括介电陶瓷生长的单晶体。根据本申请的一些实施方式，无机介电薄膜包括具有压电性质的金属氧化物、氮化物、碳化物、金属间化合物、介电陶瓷或介电单晶制备的薄膜或薄片中的一种或多种。
根据本申请的一些实施方式，非晶态介电聚合物包括亚乙烯基二氰/醋酸乙烯共聚物(P(VDCN-VAC))、亚乙烯基二氰/苯甲酸乙烯共聚物(P(VDCN-VBz))、亚乙烯基二氰/丙酸乙烯共聚物(P(VDCN-VPr))、亚乙烯基二氰/新戊酸乙烯共聚物(P(VDCN-VPiv))、亚乙烯基二氰/甲基丙烯酸甲酯共聚物(P(VDCN-MMA))或亚乙烯基二氰/异丁烯共聚物(P(VDCN-IB))中的一种或多种。根据本申请的一些实施方式，单元系压电陶瓷包括钛酸钡(BaTiO 3)、钛酸铅(PbTiO 3)、铌酸锂(LiNbO 3)或钽酸锂(LiTaO 3)中的一种或多种。根据本申请的一些实施方式，二元系压电陶瓷包括具有式PbZr xTi 1-xO 3的锆钛酸 铅，其中0＜x＜1。根据本申请的一些实施方式，三元系压电陶瓷包括具有式PbZr xTi 1-xO 3的锆钛酸铅与具有式PbMg xNb 1-xO 3的铌镁酸铅、具有式PbZn xNb 1-xO 3的铌锌酸铅或具有式PbMn xSb 1-xO 3的锰锑酸铅的混合物，根据本申请的一些实施方式，三元系压电陶瓷还包括具有式PbZr xTi 1-xO 3的锆钛酸铅与稀土元素形成的Pb 1-xM x(Zr yTi 1-y) 1-(x/4)O 3中的一种或多种，其中M为稀土金属，例如为镧(La)、铈(Ce)、镨(Pr)、钕(Nd)等，0＜x＜1，0＜y＜1。根据本申请的一些实施方式，介电单晶包括石英单晶、锗酸铋单晶(Bi 12GeO 20)、碘酸锂单晶(LiIO 3)、正磷酸铝单晶(AlPO 4)、硅酸镓镧单晶(La 3Ga 5SiO 14)、钛酸钡单晶(BaTiO 3)、氧化碲单晶或具有式PbZr xTi 1-xO 3的锆钛酸铅中的一种或多种，其中0＜x＜1。
根据本申请的一些实施方式，介电改性层在极化电场中极化后形成内建电场，极化电场的强度为介电材料的室温矫顽场强度的0.1倍至6倍，例如可以为0.1倍、0.2倍、0.5倍、1倍、2倍、3倍、4倍、5倍、6倍以及它们之间的任意值。
根据本申请的一些实施方式，负极包括负极活性材料层，负极活性材料层包括负极活性材料，负极活性材料包括锂金属、含有锂金属的复合材料、碳基材料例如石墨或硬碳、硅、含硅复合材料或钛酸锂中的一种或多种。
根据本申请的一些实施方式，固态电解质包括石榴石结构固态电解质、NASICON结构固态电解质、有机聚合物固态电解质、反钙钛矿固态电解质或硫化物固态电解质中的一种或多种。
根据本申请的一些实施方式，介电改性层包括介电材料，介电材料的室温矫顽场的强度为Ec，1kV/mm≤Ec≤60kV/mm。在一些具体实施方式中，Ec可以为1kV/mm、3kV/mm、5kV/mm、8kV/mm、15kV/mm、25kV/mm、35kV/mm、45kV/mm、55kV/mm、60kV/mm以及它们之间的任意值。
根据本申请的一些实施方式，介电改性层的厚度为L满足：100nm≤L≤3μm。在一些具体实施方式中，L可以为100nm、200nm、400nm、600nm、800nm、1μm、1.5μm、2μm、2.5μm、3μm以及它们之间的任意值。
根据本申请的一些实施方式，介电改性层在极化电场中极化后形成内建电场，极化电场的强度为3kV/mm至100kV/mm，例如可以为3kV/mm、8kV/mm、15kV/mm、25kV/mm、35kV/mm、45kV/mm、55kV/mm、65kV/mm、75kV/mm、85kV/mm、95kV/mm、100kV/mm以及它们之间的任意值。
本申请提供的电化学装置具有位于负极和固态电解质之间的介电改性层，该介电改性层内部形成从正极指向负极的有序极化电场，可以改善电极与固态电解质之间的界面接触，提升负极/电解质界面锂离子传输动力学，从而降低界面阻抗；均匀覆盖的介电改性层还可以避免固态电解质与负极之间的直接接触，避免副反应的发生，从而提升电化学装置的循环性能。
附图说明
图1是根据本申请一些实施方式的介电改性层的结构示意图(截面图)，其中1为固态电解质，2为介电改性层，3为负极活性材料层，4为铜箔，5为介电改性层的内建电场。
图2是根据本申请一些实施方式的介电改性层的极化原理示意图，其中，6为极化前的介电材料，7为极化后的介电材料。
具体实施方式
为使本申请的目的、技术方案和优点更加清楚，下面将结合实施例对本申请的技术方案进行清楚、完整地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。在此所描述的有关实施例为说明性质的且用于提供对本申请的基本理解。本申请的实施例不应该被解释为对本申请的限制。基于本申请提供的技术方案及所给出的实施例，本领域技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
为了简明，本文仅具体地公开了一些数值范围。然而，任意下限可以与任何上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，每个单独公开的点或单个数值自身可以作为下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
除非另有说明，本申请中使用的术语具有本领域技术人员通常所理解的公知含义。除非另有说明，本申请中提到的各参数的数值可以用本领域常用的各种测量方法进行测量(例如，可以按照在本申请的实施例中给出的方法进行测试)。
术语“中的至少一者”、“中的至少一个”、“中的至少一种”或其他相似术语所连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A及B中的至少一者”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目 A、B及C，那么短语“A、B及C中的至少一者”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个组分或多个组分。项目B可包含单个组分或多个组分。项目C可包含单个组分或多个组分。
本发明提供了一种电化学装置，其包括正极、负极、固态电解质和介电改性层，介电改性层位于负极和固态电解质之间，其中，介电改性层内部具有内建电场，内建电场方向为由正极指向负极。
本申请中，该介电改性层是具有铁电效应或压电效应的粉末涂层或薄膜，当其涂覆于固态电解质面对负极侧的表面，或均匀地覆盖在负极表面时，对其进行定向极化，在介电改性层内部形成从正极指向负极的有序极化电场(如图1和图2所示)，使负极表面与介电改性层负电荷端接触。由图2可知，在极化前，介电材料的电偶极矩随机排列，未形成等效电场，而极化后，介电材料的电偶极矩随极化电场方向排列，等效电场与极化电场同向。在本申请的电化学装置中，当锂离子到达电极/电解质界面处，介电改性层的内建电场将推动锂离子快速传输到负极表面，提升固-固界面处的锂离子传输动力学。另外，利用介电改性层的介电效应对固-固界面处的锂离子流进行负反馈，可以抑制固-固界面处大电流的产生，实现电流均匀化。均匀覆盖的介电改性层可以避免固态电解质与电极之间的直接接触，避免二者之间的元素互扩散，抑制副反应的发生。柔软且带有弹性的介电改性层还能改善固态电解质与电极材料的界面物理接触，降低界面阻抗从而提升电化学装置的循环性能。
根据本申请的一些实施方式，介电改性层包括介电材料，介电材料的室温矫顽场的强度为Ec，0kV/mm＜Ec≤100kV/mm。在一些具体实施方式中，Ec可以为0.5kV/mm、5kV/mm、10kV/mm、20kV/mm、30kV/mm、40kV/mm、50kV/mm、60kV/mm、70kV/mm、80kV/mm、90kV/mm、100kV/mm以及它们之间的任意值。
根据本申请的一些实施方式，介电改性层的厚度为L，100nm≤L≤5μm。在一些具体实施方式中，L可以为100nm、500nm、1μm、2μm、3μm、4μm、5μm以及它们之间的任意值。
根据本申请的一些实施方式，介电材料包括介电聚合物、介电陶瓷、介电单晶或无机介电薄膜中的一种或多种。
根据本申请的一些实施方式，介电聚合物包括聚偏氟乙烯(PVDF)、聚偏氟乙烯/聚三氟乙烯共聚物、聚偏氟乙烯/聚四氟乙烯共聚物、具有式-(HN-(CH 2) x-CO-) n-的奇数尼 龙系介电聚合物或非晶态介电聚合物中的一种或多种，其中x为偶数，n为任意正整数。根据本申请的一些实施方式，介电陶瓷包括单元系压电陶瓷、二元系压电陶瓷或三元系压电陶瓷中的一种或多种。根据本申请的一些实施方式，介电单晶包括介电陶瓷生长的单晶体。根据本申请的一些实施方式，无机介电薄膜包括具有压电性质的金属氧化物、氮化物、碳化物、金属间化合物、介电陶瓷或介电单晶制备的薄膜或薄片中的一种或多种。
根据本申请的一些实施方式，非晶态介电聚合物包括亚乙烯基二氰/醋酸乙烯共聚物(P(VDCN-VAC))、亚乙烯基二氰/苯甲酸乙烯共聚物(P(VDCN-VBz))、亚乙烯基二氰/丙酸乙烯共聚物(P(VDCN-VPr))、亚乙烯基二氰/新戊酸乙烯共聚物(P(VDCN-VPiv))、亚乙烯基二氰/甲基丙烯酸甲酯共聚物(P(VDCN-MMA))或亚乙烯基二氰/异丁烯共聚物(P(VDCN-IB))中的一种或多种。根据本申请的一些实施方式，单元系压电陶瓷包括钛酸钡(BaTiO 3)、钛酸铅(PbTiO 3)、铌酸锂(LiNbO 3)或钽酸锂(LiTaO 3)中的一种或多种。根据本申请的一些实施方式，二元系压电陶瓷包括具有式PbZr xTi 1-xO 3的锆钛酸铅，其中0＜x＜1。根据本申请的一些实施方式，三元系压电陶瓷包括具有式PbZr xTi 1-xO 3的锆钛酸铅与具有式PbMg xNb 1-xO 3的铌镁酸铅、具有式PbZn xNb 1-xO 3的铌锌酸铅或具有式PbMn xSb 1-xO 3的锰锑酸铅形成的混合物；根据本申请的一些实施方式，三元系压电陶瓷还包括具有式PbZr xTi 1-xO 3的锆钛酸铅与稀土元素形成的Pb 1-xM x(Zr yTi 1-y) 1-(x/4)O 3中的一种或多种，其中M为稀土金属，例如为镧(La)、铈(Ce)、镨(Pr)、钕(Nd)等，0＜x＜1，0＜y＜1。根据本申请的一些实施方式，介电单晶包括石英单晶、锗酸铋单晶(Bi 12GeO 20)、碘酸锂单晶(LiIO 3)、正磷酸铝单晶(AlPO 4)、硅酸镓镧单晶(La 3Ga 5SiO 14)、钛酸钡单晶(BaTiO 3)、氧化碲单晶或具有式PbZr xTi 1-xO 3的锆钛酸铅中的一种或多种，其中0＜x＜1。
根据本申请的一些实施方式，介电改性层在极化电场中极化后形成内建电场，极化电场的强度为介电材料的室温矫顽场强度的0.1倍至6倍，例如可以为0.1倍、0.2倍、0.5倍、1倍、2倍、3倍、4倍、5倍、6倍以及它们之间的任意值。
根据本申请的一些实施方式，负极包括负极活性材料层，负极活性材料层包括负极活性材料，负极活性材料包括锂金属、含有锂金属的复合材料、碳基材料例如石墨或硬碳、硅、含硅复合材料或钛酸锂中的一种或多种。
根据本申请的一些实施方式，固态电解质包括石榴石结构固态电解质、NASICON结构固态电解质、有机聚合物固态电解质、反钙钛矿固态电解质或硫化物固态电解质中的一种或多种。
根据本申请的一些实施方式，介电改性层包括介电材料，介电材料的室温矫顽场的强度为Ec，1kV/mm≤Ec≤60kV/mm。在一些具体实施方式中，Ec可以为1kV/mm、3kV/mm、5kV/mm、8kV/mm、15kV/mm、25kV/mm、35kV/mm、45kV/mm、55kV/mm、60kV/mm以及它们之间的任意值。
根据本申请的一些实施方式，介电改性层的厚度为L满足：100nm≤L≤3μm。在一些具体实施方式中，L可以为100nm、200nm、400nm、600nm、800nm、1μm、1.5μm、2μm、2.5μm、3μm以及它们之间的任意值。
根据本申请的一些实施方式，介电改性层在极化电场中极化后形成内建电场，极化电场的强度为3kV/mm至100kV/mm，例如可以为3kV/mm、8kV/mm、15kV/mm、25kV/mm、35kV/mm、45kV/mm、55kV/mm、65kV/mm、75kV/mm、85kV/mm、95kV/mm、100kV/mm以及它们之间的任意值。
固态电解质
可用于本申请的实施方式中固态电解质的材料、构成和其制造方法包括任何现有技术中公开的技术。
根据本申请的一些实施方式，固态电解质包括石榴石结构固态电解质、NASICON结构固态电解质、有机聚合物固态电解质、反钙钛矿固态电解质或硫化物固态电解质中的一种或多种。根据本申请的一些具体的实施方式，石榴石结构固态电解质包括Li 7La 3Zr 2O 12或Li 6.4La 3Zr 1.4Ta 0.6O 12等，NASICON结构固态电解质的非限制性示例包括Li 1.3Al 0.3Ti 1.7(PO 4) 3等，有机聚合物固态电解质的非限制性示例包括聚环氧乙烷(-[-CH 2─CH 2─O-]- n)或聚丙烯腈(C 3H 3N) n)等，反钙钛矿固态电解质的非限制性示例包括Li 3OX(X＝Cl或Br)等，硫化物固态电解质的非限制性示例包括Li 6PS 5Cl，Li 11Ge 2PS 12等。
负极
可用于本申请的实施方式中负极的材料、构成和其制造方法包括任何现有技术中公开的技术。
根据本申请的一些实施方式，负极包括负极活性材料层，负极活性材料层包括负极活性材料，负极活性材料包括锂金属、含有锂金属的复合材料、碳基材料例如人造石墨、天然石墨或硬碳等、硅及含硅复合材料或钛酸锂中的一种或多种。
在一些实施方式中，负极活性材料层可以包括粘合剂，并且可选地还包括导电材料，从而赋予电极导电性。粘合剂提高负极活性材料颗粒彼此间的结合和负极活性材料与集流 体的结合。粘合剂的非限制性示例包括聚乙烯醇、羧甲基纤维素、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1,1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙等。该导电材料可以包括任何导电材料，只要它不引起化学变化。导电材料的非限制性示例包括基于碳的材料(例如，天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维等)、基于金属的材料(例如，金属粉、金属纤维等，例如铜、镍、铝、银等)、导电聚合物(例如，聚亚苯基衍生物)和它们的混合物。
正极
可用于本申请的实施方式中正极的材料、构成和其制造方法包括任何现有技术中公开的技术。
在一些实施方式中，正极包括正极集流体和位于正极集流体上的正极活性材料层。正极活性材料包括可逆地嵌入和脱嵌锂离子的至少一种锂化插层化合物。在一些实施方式中，正极活性材料包括复合氧化物。在一些实施方式中，该复合氧化物含有锂以及从钴、锰和镍中选择的至少一种元素。在一些实施方式中，正极活性材料选自钴酸锂(LiCoO 2)、锂镍钴锰(NCM)三元材料、磷酸亚铁锂(LiFePO 4)、锰酸锂(LiMn 2O 4)或它们的任意组合。
正极活性材料层还包括粘合剂，并且可选地包括导电材料。粘合剂提高正极活性材料颗粒彼此间的结合，并且还提高正极活性材料与集流体的结合。在一些实施方式中，粘合剂包括，但不限于：聚乙烯醇、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1，1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂、尼龙等。在一些实施方式中，导电材料包括，但不限于：基于碳的材料、基于金属的材料、导电聚合物和它们的混合物。在一些实施方式中，基于碳的材料选自天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维或其任意组合。在一些实施方式中，基于金属的材料选自金属粉、金属纤维、铜、镍、铝、银。在一些实施方式中，导电聚合物为聚亚苯基衍生物。
在一些实施方式中，正极集流体可以是铝，但不限于此。
在一些实施方式中，本申请的电化学装置包括，但不限于：所有种类的一次电池、二次电池、燃料电池、太阳能电池或电容。在一些实施方式中，电化学装置是锂二次电池。在一些实施方式中，锂二次电池包括，但不限于：锂金属二次电池、锂离子二次电池、锂聚合物二次电池或锂离子聚合物二次电池。
本申请还提供了使用根据本申请的电化学装置的电子装置。
在一些实施方式中，电子装置包括，但不限于：笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池或锂离子电容器等。
下面结合实施例，进一步阐述本申请。应理解，这些实施例仅用于说明本申请而不用于限制本申请的范围。
测试方法
1.介电材料的室温矫顽场的强度
使用标准电滞回线测量仪(型号：BZ-MTF-DH1)测试介电材料室温矫顽场。将样品放入样品盒中，样品盒通过电缆连接至测试主机信号接入端，关闭样品盒。接通样品盒电源，调节极化电压，点击开始测试，可获得材料电滞回线，读取室温矫顽场数值。
2.介电改性层的内部内建电场方向
使用万用表测试介电改性层内建电场方向。当介电材料层受到应力作用发生形变，则材料内部电偶极矩也随之发生变化，宏观上表现为内建电场发生变化。此时若电压表正负表针与该改性层的两面分别接触，并对改性层施加压力，由于电场变化电压表指针将发生偏转，可测得电压信号，根据电压信号正负性可获得电场方向信息。
3.介电改性层厚度
用螺旋千分尺测试厚度。未涂覆前先测试记录基底材料厚度为t1，涂覆介电改性层后测试记录介电改性层+基底厚度为t2，则介电改性层厚度为t1-t2。
4.容量保持率为80％的循环圈数
将电池在25℃下以0.1C的充电倍率和放电倍率化成一圈，然后，在测试温度为25℃条件下，以0.3C恒流充电到4.3V，再恒压充电到0.05C，静置5分钟后以1C放电到2.8V。以此步得到的容量为初始容量，进行0.3C充电/1C放电进行循环测试，以每一步的容量 与初始容量做比值，得到容量衰减曲线。以25℃循环截至到容量保持率为80％的圈数记为电池的室温循环性能。
实施例及对比例
实施例1
(1)介电改性固态电解质制备
a)介电改性层的制备
将偏氟乙烯/三氟乙烯共聚物(PVDF-TrFE)粉末分散于N-甲基吡咯烷酮(NMP)中，通过搅拌使PVDF-TrFE分散均匀，涂覆于Li 10GeP 2S 12固态电解质表面得到介电改性固态电解质，在真空干燥箱中80℃烘干待用，烘干后介电改性层厚度为1μm。
b)极化操作
将上述介电改性固态电解质放置于平行电场中进行极化，极化装置包括用于产生平行电场的正极压板和负极压板，正极压板和负极压板之间的平行电场方向由正电压板指向负电压板，极化电场场强为10kV/mm，极化时间为30min，介电改性层面对正电压板侧。完成后，将固态电解质裁切成直径20mm的圆片待用。
(2)正极极片的制备
将三元正极活性材料(LiNi 0.8Co 0.1Mn 0.1O 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上，90℃条件下烘干，得到正极极片。涂布完成后，将极片裁切成直径16mm的圆片待用。
(3)负极极片的制备
将锂金属箔、负极集流体铜箔按顺序堆叠并冷压后，裁切成直径为18mm的圆片待用。
(4)锂金属电池的制备
将上述正极极片、改性固态电解质、负极极片按顺序堆叠后组装成扣式电池。其中，介电改性层位于负极和固态电解质之间。
实施例2至实施例4
与实施例1的不同仅在于步骤(1)的b)中，极化电场的强度不同，具体参见表1。
实施例5至实施例7
与实施例1的不同仅在于步骤(1)的a)中，介电改性层厚度不同，具体参见表1。
实施例8
(1)介电改性负极极片制备
a)负极极片的制备
将锂金属箔、负极集流体铜箔按顺序堆叠并冷压后，裁切成直径为18mm的圆片待用。
b)介电改性层的制备
将PVDF-TrFE粉末分散于NMP中，通过搅拌使PVDF-TrFE分散均匀，使用刮刀涂覆于步骤a)得到的负极极片表面，在真空干燥箱中80℃烘干待用，烘干后厚度为0.1μm。
c)极化操作：
将上述介电改性负极极片放置于平行电场中进行极化，极化电场为50kV/mm，极化时间为30min，介电改性层面对负电压板侧。
(2)正极极片的制备
将正极活性材料磷酸铁锂(LiFePO 4)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上，90℃条件下烘干，得到正极极片。涂布完成后，将极片裁切成直径为16mm的圆片待用。
(3)锂电池的制备
将上述介电改性负极极片、直径为20mm的Li 10GeP 2S 12固态电解质圆片、正极极片按顺序堆叠后组装成扣式电池。其中，介电改性层位于负极和固态电解质之间。
实施例9至实施例11
与实施例9的不同仅在于步骤(1)的a)中，介电改性层厚度不同，具体参见表1。
实施例12至实施例14
与实施例9的不同仅在于步骤(1)的b)中，极化电场的强度不同，具体参见表1。
实施例15
(1)介电改性固态电解质制备
a)介电改性层的制备
将PVDF-TrFE粉末分散于NMP中，通过搅拌使PVDF-TrFE分散均匀，涂覆于Li10GeP2S12固态电解质表面得到介电改性固态电解质，在真空干燥箱中80℃烘干待用，烘干后介电改性层厚度为1μm。
b)极化操作
将上述介电改性固态电解质放置于平行电场中进行极化，极化电场为50kV/mm，极化时间为30min，介电改性层面对正电压板侧。完成后，将固态电解质裁切成直径20mm的圆片规格待用。
(2)正极极片的制备
将三元正极活性材料(LiNi 0.8Co 0.1Mn 0.1O 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上，90℃条件下烘干，得到正极极片。涂布完成后，将极片裁切成直径16mm的哟规格待用。
(3)负极极片的制备
将人造石墨、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97:1.0:2.0进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为80％的浆料，并搅拌均匀。将浆料均匀涂覆在负极集流体铜箔上，80℃条件下烘干，得到负极极片。涂布完成后，将极片裁切成直径18mm的圆片规格待用。
(4)锂电池的制备
将上述负极极片、介电改性固态电解质、正极极片按顺序堆叠后组装成扣式电池。其中，介电改性层位于负极和固态电解质之间。
实施例16
(1)介电改性固态电解质制备
a)介电改性层的制备
将PVDF-TrFE粉末分散于NMP中，通过搅拌使PVDF-TrFE分散均匀，涂覆于Li10GeP2S12固态电解质表面得到介电改性固态电解质，在真空干燥箱中80℃烘干待用，烘干后介电改性层厚度为1μm。
b)极化操作
将介电改性上述固态电解质放置于平行电场中进行极化，极化电场为50kV/mm，极化时间为30min，介电改性层面对正电压板侧。完成后，将固态电解质裁切成直径20mm的圆片规格待用。
(2)正极极片的制备
将三元正极活性材料(LiNi 0.8Co 0.1Mn 0.1O 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上，90℃条件下烘干，得到正极极片。涂布完成后，将极片裁切成直径16mm的圆片规格待用。
(3)负极极片的制备
将5％Si-C复合材料(其中，Si的重量比为5％)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97:1.0:2.0进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为80％的浆料，并搅拌均匀。将浆料均匀涂覆在负极集流体铜箔上，80℃条件下烘干，得到负极极片。涂布完成后，将极片裁切成直径18mm的规格待用。
(4)锂电池的制备
将上述负极极片、介电改性固态电解质、正极极片按顺序堆叠后组装成扣式电池。其中，介电改性层位于负极和固态电解质之间。
实施例17
(1)介电改性固态电解质制备
a)介电改性层的制备
将PVDF-TrFE粉末分散于NMP中，通过搅拌使PVDF-TrFE分散均匀，涂覆于Li 10GeP 2S 12固态电解质表面得到介电改性固态电解质，在真空干燥箱中80℃烘干待用，烘干后介电改性层厚度为1μm。
b)极化操作
将上述介电改性固态电解质放置于平行电场中进行极化，极化电场为50kV/mm，极化时间为30min，介电改性层面对正电压板侧。完成后，将固态电解质裁切成直径20mm的圆片规格待用。
(2)正极极片的制备
将三元正极活性材料(LiNi 0.8Co 0.1Mn 0.1O 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂， 调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上，90℃条件下烘干，得到正极极片。涂布完成后，将极片裁切成直径16mm的圆片规格待用。
(3)负极极片的制备
将钛酸锂负极活性材料、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97:1.0:2.0进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为80％的浆料，并搅拌均匀。将浆料均匀涂覆在负极集流体铜箔上，80℃条件下烘干，得到负极极片。涂布完成后，将极片裁切成直径18mm的圆片规格待用。
(4)锂电池的制备
将上述负极极片、介电改性固态电解质、正极极片按顺序堆叠后组装成扣式电池。其中，介电改性层位于负极和固态电解质之间。
实施例18
(1)介电改性固态电解质制备
a)介电改性层的制备
将BaTiO 3粉末分散于NMP中，通过搅拌使BaTiO 3粉末分散均匀，涂覆于Li 10GeP 2S 12固态电解质表面得到介电改性固态电解质，在真空干燥箱中80℃烘干待用，烘干后介电改性层厚度为1μm。
b)极化操作
将上述固态电解质放置于平行电场中进行极化，极化电场为3kV/mm，极化时间为30min，介电改性层面对正电压板侧。完成后，将固态电解质裁切成直径20mm的圆片规格待用。
(2)正极极片的制备
将三元正极活性材料(LiNi 0.8Co 0.1Mn 0.1O 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上，90℃条件下烘干，得到正极极片。涂布完成后，将极片裁切成直径16mm的圆片规格待用。
(3)负极极片制备
将锂金属箔、负极集流体铜箔按顺序堆叠并冷压后，裁切成直径为18mm的圆片待用。
(4)锂电池的制备
将上述负极极片、介电改性固态电解质、正极极片按顺序堆叠后组装成扣式电池。其中，介电改性层位于负极和固态电解质之间。
实施例19
(1)介电改性固态电解质制备
a)介电改性层的制备
将摩尔比为5:3:2的PbO、ZrO 2、TiO 2置于高能行星球磨机中，加入100ml乙醇作为球磨助剂，以250r/min的转速球磨30h，得到钛锆酸铅PbZr 0.6Ti 0.4O 3粉末。将PbZr 0.6Ti 0.4O 3粉末分散于NMP中，通过搅拌使PbZr 0.6Ti 0.4O 3粉末分散均匀，得到固含量为12％的浆料，将浆料均匀涂覆于Li 10GeP 2S 12固态电解质表面得到介电改性固态电解质，在真空干燥箱中80℃烘干待用，烘干后介电改性层厚度为1μm。
b)极化操作
将上述介电改性固态电解质放置于平行电场中进行极化，极化电场为3kV/mm，极化时间为30min，介电改性层面对正电压板侧。完成后，将固态电解质裁切成直径20mm的圆片规格待用。
(2)正极极片的制备
将三元正极活性材料(LiNi 0.8Co 0.1Mn 0.1O 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上，90℃条件下烘干，得到正极极片。涂布完成后，将极片裁切成直径16mm的圆片规格待用。
(3)负极极片制备
将锂金属箔、负极集流体铜箔按顺序堆叠并冷压后，裁切成直径为18mm的圆片待用。
(4)锂电池的制备
将上述负极极片、介电改性固态电解质、正极极片按顺序堆叠后组装成扣式电池。其中，介电改性层位于负极和固态电解质之间。
实施例20
(1)介电改性负极极片制备
将锂金属箔、负极集流体铜箔按顺序堆叠并冷压后得到负极极片；
将厚度为5μm的尼龙7薄膜(品牌：台湾化学纤维股份有限公司，牌号：NP4000)放置于平行电场中进行空气极化，极化电场为280kV/mm，极化时间为30min，极化电场方向平行于薄膜厚度方向且保持恒定。完成后，极化后尼龙7薄膜带负电方向贴在负极极片表面，得到介电改性层厚度为5μm的介电改性负极极片，将介电改性负极极片裁切成直径18mm的圆片规格待用。
(2)正极极片的制备
将正极活性材料磷酸铁锂(LiFePO 4)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上，90℃条件下烘干，得到正极极片。涂布完成后，将极片裁切成直径16mm的圆片规格待用。
(3)锂电池的制备
将上述介电改性负极极片、直径为20mm的Li 10GeP 2S 12固态电解质圆片、正极极片按顺序堆叠后组装成扣式电池。其中，介电改性层位于负极和固态电解质之间。
实施例21
(1)介电改性负极极片制备
将锂金属箔、负极集流体铜箔按顺序堆叠并冷压后得到负极极片；
将厚度为5μm的氧化碲晶体单晶片(品牌：北京物科光电技术有限公司，牌号：TEO2)放置于平行电场中进行空气极化，极化电场为3kV/mm，极化时间为30min，极化电场方向平行于单晶片厚度方向且保持恒定。完成后，极化后氧化碲晶体单晶片带负电方向贴在负极极片表面，得到介电改性层厚度为5μm的介电改性负极极片，将负极极片裁切成直径18mm的圆片规格待用。
(2)正极极片的制备
将正极活性材料磷酸铁锂(LiFePO 4)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在正极集流体铝箔上，90℃条件下烘干，得到正极极片。涂布完成后，将极片裁切成直径16mm的圆片规格待用。
(3)锂电池的制备
将介电改性负极极片、直径为20mm的Li 10GeP 2S 12固态电解质圆片、正极极片按顺序堆叠后组装成扣式电池。其中，介电改性层位于负极和固态电解质之间。
对比例1
与实施例1的不同在于固体电解质不含有介电改性层，即所制备的扣式电池不含有介电改性层，具体参见表1。
表1
Figure PCTCN2022083729-appb-000001
根据实施例1至实施例14和对比例1可以看出，包括本申请所提供的介电改性层的电化学装置，即电化学装置包括正极、负极、固态电解质和介电改性层，介电改性层位于负极和固态电解质之间，介电改性层内部具有内建电场，内建电场方向为由正极指向负极，其循环性能明显优于未设置介电改性层的电化学装置。归因于介电改性层内的内建电场将推动锂离子快速传输到负极表面，可提升固-固界面处的锂离子传输动力学、抑制固-固界面处大电流的产生并实现电流均匀化以及抑制副反应的发生，从而显著提升电化学装置的循环性能。
根据实施例2、实施例15至实施例17可以看出，对于不同种类的负极，利用本申请范围内的极化电场强度及方向对介电改性层进行极化后，均可以有效提升电化学装置的循环性能。
根据实施例1至实施例4、实施例8以及实施例12至实施例14可以看出，电化学装置中选用同一种类的介电改性层时，无论位于固态电解质负极侧(即固态电解质和负极之间)还是负极表面，采用本申请范围内的极化电场强度及方向对介电改性层进行极化后，均可以有效提升电化学装置的循环性能。
根据实施例2、实施例5至实施例7以及实施例8至实施例11可以看出，采用在本申请范围内的介电改性层的厚度，电化学装置的循环性能更好。
根据实施例18至实施例21可以看出，介电材料的室温矫顽场强度决定了其内建电场的稳定性，采用矫顽场强度在本申请范围内的介电材料改性层，能够进一步改善电化学装置的循环性能。
虽然已经说明和描述了本申请的一些示例性实施方式，然而本申请不限于所公开的实施方式。相反，本领域普通技术人员将认识到，在不脱离如所附权利要求中描述的本申请的精神和范围的情况下，可对所描述的实施方式进行一些修饰和改变。

Claims (10)

  1. 一种电化学装置，其包括正极、负极、固态电解质和介电改性层，所述介电改性层位于所述负极和所述固态电解质之间，其中，所述介电改性层内部具有内建电场，所述内建电场方向为由正极指向负极。
  2. 根据权利要求1所述的电化学装置，其特征在于，所述介电改性层包括介电材料，所述介电材料的室温矫顽场的强度为Ec，0kV/mm＜Ec≤100kV/mm。
  3. 根据权利要求1所述的电化学装置，其特征在于，所述介电改性层的厚度为L，100nm≤L≤5μm。
  4. 根据权利要求2所述的电化学装置，其特征在于，所述介电材料包括介电聚合物、介电陶瓷、介电单晶或无机介电薄膜中的一种或多种。
  5. 根据权利要求4所述的电化学装置，其特征在于，所述介电聚合物包括聚偏氟乙烯、聚偏氟乙烯/聚三氟乙烯共聚物、聚偏氟乙烯/聚四氟乙烯共聚物、具有式-(HN-(CH 2) x-CO-) n-的奇数尼龙系介电聚合物或非晶态介电聚合物中的一种或多种，其中x为偶数，n为任意正整数；
    所述介电陶瓷包括单元系压电陶瓷、二元系压电陶瓷或三元系压电陶瓷中的一种或多种；
    所述介电单晶包括介电陶瓷生长的单晶体；
    所述无机介电薄膜包括具有压电性质的金属氧化物、氮化物、碳化物、金属间化合物、所述介电陶瓷或所述介电单晶制备的薄膜或薄片中的一种或多种。
  6. 根据权利要求5所述的电化学装置，其特征在于，所述非晶态介电聚合物包括亚乙烯基二氰/醋酸乙烯共聚物、亚乙烯基二氰/苯甲酸乙烯共聚物、亚乙烯基二氰/丙酸乙烯共聚物、亚乙烯基二氰/新戊酸乙烯共聚物、亚乙烯基二氰/甲基丙烯酸甲酯共聚物或亚乙烯基二氰/异丁烯共聚物中的一种或多种；
    所述单元系压电陶瓷包括钛酸钡、钛酸铅、铌酸锂或钽酸锂中的一种或多种；
    所述二元系压电陶瓷包括具有式PbZr xTi 1-xO 3的锆钛酸铅，其中0＜x＜1；
    所述三元系压电陶瓷包括具有式PbZr xTi 1-xO 3的锆钛酸铅与具有式PbMg xNb 1-xO 3的铌镁酸铅、具有式PbZn xNb 1-xO 3的铌锌酸铅或具有式PbMn xSb 1-xO 3的锰锑酸铅形成的混合物中的一种或多种；
    所述三元系压电陶瓷包括具有式PbZr xTi 1-xO 3的锆钛酸铅与稀土元素形成的Pb 1-xM x(Zr yTi 1-y) 1-(x/4)O 3中的一种或多种，其中M为稀土金属，0＜x＜1，0＜y＜1；
    所述介电单晶包括石英单晶、锗酸铋单晶、碘酸锂单晶、正磷酸铝单晶、硅酸镓镧单晶、钛酸钡单晶、氧化碲单晶或具有式PbZr xTi 1-xO 3的锆钛酸铅中的一种或多种，其中0＜x＜1。
  7. 根据权利要求1所述的电化学装置，其特征在于，所述介电改性层在极化电场中极化后形成所述内建电场，所述极化电场的强度为所述介电材料的室温矫顽场强度的0.1倍至6倍。
  8. 根据权利要求1所述的电化学装置，其特征在于，所述负极包括负极活性材料层，所述负极活性材料层包括负极活性材料，所述负极活性材料包括锂金属、含有锂金属的复合材料、包括石墨或硬碳的碳基材料、硅、含硅复合材料或钛酸锂中的一种或多种。
  9. 根据权利要求1所述的电化学装置，其特征在于，所述固态电解质包括石榴石结构固态电解质、NASICON结构固态电解质、有机聚合物固态电解质、反钙钛矿固态电解质或硫化物固态电解质中的一种或多种。
  10. 根据权利要求1至9中任一项所述的电化学装置，其满足以下条件中的至少一者：
    (1)所述介电改性层包括介电材料，所述介电材料的室温矫顽场的强度为Ec，1kV/mm≤Ec≤60kV/mm；
    (2)所述介电改性层的厚度为L满足：100nm≤L≤3μm；
    (3)所述介电改性层在极化电场中极化后形成内建电场，所述极化电场的强度为3kV/mm至100kV/mm。
PCT/CN2022/083729 2022-03-29 2022-03-29 电化学装置 WO2023184159A1 (zh)

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CN105826508A (zh) * 2016-05-27 2016-08-03 北京师范大学 压电陶瓷复合隔膜、其制备方法及锂离子电池
CN109417189A (zh) * 2016-06-30 2019-03-01 罗伯特·博世有限公司 电解质
CN111463403A (zh) * 2020-04-13 2020-07-28 武汉大学 复合人工固态电解质界面膜修饰的负极材料及其电池应用
WO2021080052A1 (ko) * 2019-10-25 2021-04-29 주식회사 그리너지 리튬 메탈 음극 구조체, 이를 포함하는 전기화학소자, 및 상기 리튬 메탈 음극 구조체의 제조방법
CN114175304A (zh) * 2021-03-31 2022-03-11 宁德新能源科技有限公司 一种负极极片、包含该负极极片的电化学装置及电子装置

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CN105826508A (zh) * 2016-05-27 2016-08-03 北京师范大学 压电陶瓷复合隔膜、其制备方法及锂离子电池
CN109417189A (zh) * 2016-06-30 2019-03-01 罗伯特·博世有限公司 电解质
WO2021080052A1 (ko) * 2019-10-25 2021-04-29 주식회사 그리너지 리튬 메탈 음극 구조체, 이를 포함하는 전기화학소자, 및 상기 리튬 메탈 음극 구조체의 제조방법
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