Solid-state electrolyte thin film and solid-state battery
By introducing an oxide electrolyte layer with a specific structure into a solid electrolyte film, the problem of balancing ionic conductivity and stability in traditional solid electrolyte films is solved, improving the overall performance of the battery and making it suitable for new energy vehicles and consumer electronics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHONGQING TALENT NEW ENERGY CO LTD
- Filing Date
- 2025-07-04
- Publication Date
- 2026-07-24
Smart Images
Figure CN224554364U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of battery technology, specifically relating to a solid electrolyte film and a solid battery. Background Technology
[0002] Since their commercialization in the 1990s, lithium-ion batteries have gradually permeated all aspects of people's lives. With continuous technological development and progress, the demand for energy density in lithium-ion batteries is increasing, while the safety issues of traditional liquid lithium-ion batteries are becoming increasingly serious. Liquid lithium-ion batteries, due to the use of flammable organic electrolytes and thermally unstable separators, pose significant safety hazards at high temperatures, limiting their further development and application. Replacing traditional liquid electrolytes and separators with stable solid-state electrolytes is an effective way to improve the safety of lithium-ion batteries. Solid-state batteries not only achieve inherent battery safety but also have higher energy density, and are considered a significant technological innovation in the fields of new energy vehicles and consumer electronics. Currently in a phase of rapid development, they are expected to become the next generation of batteries.
[0003] Inorganic oxide electrolyte films are considered to have great commercial application prospects due to their high mechanical strength, good thermal stability, and wide electrochemical window. However, oxide electrolyte films still face problems such as limited ionic conductivity and interfacial compatibility with positive and negative electrodes. Doping can effectively improve the ionic conductivity of oxide electrolytes, but may lead to a decrease in electrolyte stability. Electrolyte film structure design can improve the interfacial compatibility between the electrolyte film and the positive and negative electrodes to a certain extent, but it has a certain impact on the ionic conductivity of the oxide electrolyte film. Therefore, it is difficult to achieve both ionic conductivity and stability in solid-state electrolyte films. Utility Model Content
[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a solid electrolyte film and a solid-state battery. The solid electrolyte film provided in this application can balance ionic conductivity and stability.
[0005] In a first aspect, the present invention provides a solid electrolyte film comprising a positive electrode buffer layer, a lithium-ion fast conduction layer, and a negative electrode buffer layer stacked sequentially, wherein the positive electrode buffer layer comprises a NASICON-type oxide electrolyte; the lithium-ion fast conduction layer comprises alternating layers of glassy oxide electrolyte layer and garnet-type oxide electrolyte layer; and the negative electrode buffer layer comprises a perovskite-type oxide electrolyte.
[0006] According to the solid electrolyte film of the above embodiments of this utility model, the alternating structure of glassy oxide electrolyte layer and garnet oxide electrolyte layer in the lithium-ion fast conduction layer effectively solves the problem that traditional solid electrolyte films cannot simultaneously possess excellent ionic conductivity and good stability. To better match the positive and negative electrodes in solid-state batteries, positive and negative electrode buffer layers are designed on both sides of the lithium-ion fast conduction layer. The NASICON-type oxide material of the positive electrode buffer layer not only has excellent compatibility and good mechanical properties with the positive electrode, effectively reducing the interfacial impedance between the positive electrode and the solid electrolyte film, but also avoids side reactions from contact with the negative electrode. The perovskite oxide electrolyte of the negative electrode buffer layer has good compatibility with the negative electrode and can prevent the growth of lithium dendrites on the negative electrode surface during battery cycling. The entire composite oxide electrolyte film has the advantages of chemical stability, high ionic conductivity, and cycle stability, while also being well compatible with the positive and negative electrode materials in the battery, significantly improving the performance of solid-state lithium-ion batteries and facilitating their industrial application. In summary, the solid electrolyte film proposed in this application can balance ionic conductivity and stability.
[0007] In addition, the solid electrolyte film according to the above embodiments of the present invention may also have the following additional technical features:
[0008] In some embodiments of this invention, the NASICON-type oxide electrolyte includes any one of lithium aluminum titanium phosphate and lithium aluminum germanium phosphate. Therefore, the solid electrolyte film can balance ionic conductivity and stability.
[0009] In some embodiments of this invention, the NASICON-type oxide electrolyte comprises lithium aluminum titanium phosphate. Thus, the solid electrolyte film can balance ionic conductivity and stability.
[0010] In some embodiments of this invention, the thickness of the positive electrode buffer layer is 100nm-1000nm. Therefore, the solid electrolyte film can balance ionic conductivity and stability.
[0011] In some embodiments of this invention, the total number of the glassy oxide electrolyte layer and the garnet-type oxide electrolyte layer is 2 to 50 layers. Thus, the solid electrolyte film can balance ionic conductivity and stability.
[0012] In some embodiments of this invention, the thickness of the lithium-ion fast conduction layer is 200nm-5000nm. Therefore, the solid electrolyte film can balance ionic conductivity and stability.
[0013] In some embodiments of this invention, the thickness of a single glassy oxide electrolyte layer is 100 nm to 200 nm. Therefore, the solid electrolyte film can balance ionic conductivity and stability.
[0014] In some embodiments of this invention, the thickness of a single garnet-type oxide electrolyte layer is 100 nm-200 nm. Thus, the solid electrolyte film can balance ionic conductivity and stability.
[0015] In some embodiments of this invention, the glassy oxide electrolyte layer includes any one of LiPON and LiSiPON. Thus, the solid electrolyte film can balance ionic conductivity and stability.
[0016] In some embodiments of this invention, the garnet-type oxide electrolyte layer comprises lithium lanthanum zirconium oxide. Thus, the solid electrolyte film can balance ionic conductivity and stability.
[0017] In some embodiments of this invention, the perovskite oxide electrolyte comprises lithium lanthanum titanium oxide. Thus, the solid electrolyte film can balance ionic conductivity and stability.
[0018] In some embodiments of this invention, the thickness of the negative electrode buffer layer is 100nm-1000nm. Therefore, the solid electrolyte film can balance ionic conductivity and stability.
[0019] In a second aspect, this invention provides a solid-state battery comprising a positive electrode, a solid electrolyte film as described in the first aspect, and a negative electrode, stacked sequentially, wherein the positive electrode is in contact with the positive electrode buffer layer, and the negative electrode is in contact with the negative electrode buffer layer. Thus, the solid-state battery containing this solid electrolyte film exhibits excellent ionic conductivity and stability.
[0020] In some embodiments of this invention, the negative electrode comprises lithium metal. Therefore, the solid-state battery exhibits excellent energy density, as well as excellent ionic conductivity and stability.
[0021] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0022] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0023] Figure 1A schematic diagram of the structure of the solid electrolyte film provided by this utility model is shown.
[0024] Figure 2 Showing Figure 1 A schematic diagram of the structure of one embodiment of the lithium-ion fast conduction layer.
[0025] Figure 3 A schematic diagram of the solid-state battery provided by this utility model is shown.
[0026] Icon labels:
[0027] Positive electrode 1, positive electrode buffer layer 2, lithium-ion fast conduction layer 3, glassy oxide electrolyte layer 31, garnet oxide electrolyte layer 32, negative electrode buffer layer 4, negative electrode 5. Detailed Implementation
[0028] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.
[0029] In a first aspect, this utility model provides a solid electrolyte thin film, please refer to [link to relevant documentation]. Figure 1 and Figure 2 The solid electrolyte film includes a positive electrode buffer layer 2, a lithium-ion fast conduction layer 3, and a negative electrode buffer layer 4 stacked sequentially. The positive electrode buffer layer 2 includes a NASICON-type oxide electrolyte; the lithium-ion fast conduction layer 3 includes an alternately stacked glassy oxide electrolyte layer 31 and a garnet-type oxide electrolyte layer 32; and the negative electrode buffer layer 4 includes a perovskite-type oxide electrolyte.
[0030] According to the solid electrolyte film of the above embodiment of this utility model, the alternating structure of glassy oxide electrolyte layer 31 and garnet oxide electrolyte layer 32 in the lithium-ion fast conduction layer 3 effectively solves the problem that traditional solid electrolyte films cannot simultaneously possess excellent ionic conductivity and good stability. To better match with the positive and negative electrodes in the battery, a positive electrode buffer layer 2 and a negative electrode buffer layer 4 are designed on both sides of the lithium-ion fast conduction layer 3. The NASICON-type oxide electrolyte in the positive electrode buffer layer 2 not only has excellent compatibility and good mechanical properties with the positive electrode, effectively reducing the interfacial impedance between the positive electrode sheet 1 and the solid electrolyte film, but also avoids side reactions from contact with the negative electrode sheet 5. The perovskite-type oxide electrolyte in the negative electrode buffer layer 4 has good compatibility with the negative electrode sheet 5, and can also prevent the growth of lithium dendrites on the negative electrode surface during battery cycling. The entire composite oxide solid electrolyte film has the advantages of chemical stability, high ionic conductivity, and cycle stability, while also being well compatible with the positive and negative electrode materials in the battery, significantly improving the performance of solid-state lithium-ion batteries and facilitating their industrial application. In summary, the solid electrolyte film proposed in this application can balance ionic conductivity and stability.
[0031] It can be understood that the garnet-type oxide electrolyte layer 32 includes a garnet-type oxide electrolyte, which is a solid electrolyte material with a garnet crystal structure. The garnet-type oxide electrolyte itself has high ionic conductivity, which can dominate ion transport and provide a fast channel to promote the efficient migration of lithium ions. The glassy oxide electrolyte layer 31 includes a glassy oxide electrolyte, which is an amorphous solid electrolyte material. Its internal structure lacks long-range order and is similar to the structure of ordinary glass. It can improve interfacial transport, thereby further improving the overall ion conduction efficiency.
[0032] Garnet-type oxide electrolytes and glassy oxide electrolytes inherently possess excellent chemical and structural stability. Furthermore, the flexibility of glassy oxide electrolytes helps mitigate stress changes during battery charging and discharging, and its low electronic conductivity effectively suppresses side reactions. The combination of these two factors further enhances the mechanical stability of the alternating structure. The alternating multilayer configuration amplifies the excellent ionic conductivity of garnet-type oxide electrolytes and the flexibility and low electronic conductivity of glassy oxide electrolytes, enabling the overall solid electrolyte film to exhibit higher conductivity, better strain resistance, and improved structural stability.
[0033] NASICON-type oxide electrolytes are a class of solid-state electrolyte materials with special crystal structures and excellent ion conductivity. Their name derives from their typical crystal structure and composition, namely Na₂O₃. x A y Z z(PO4)3 (x = 3, y = 2, z = 2), where Na represents sodium ions, A and Z represent other metal ions (such as Ti, Al, Mg, etc.), and PO4 represents phosphate ions. This material was originally designed for sodium-ion batteries, but by replacing sodium ions with lithium ions, it can also be used in lithium-ion batteries. In the embodiments of this application, the NASICON-type oxide electrolyte has a stable three-dimensional channel structure, which can provide good ion channels, thereby achieving efficient charge transfer and good interfacial contact; it has good chemical stability and is not prone to chemical reaction with the positive electrode material; it has good mechanical properties, which can ensure structural stability; and it has a wide electrochemical window. Using this material as the positive electrode buffer layer 2 can achieve good compatibility between the solid electrolyte film and the positive electrode 1.
[0034] Perovskite oxide electrolytes are solid-state electrolyte materials with a perovskite crystal structure. The general formula for the perovskite structure is ABO3, where: A represents the larger cation, usually a rare earth element or alkaline earth metal (such as La, Li, Sr, Ba, etc.); B represents the smaller cation, usually a transition metal (such as Ti, Co, Fe, Ni, etc.); and O represents the oxygen ion, through the trivalent rare earth ion La. 3+ and monovalent alkaline earth cations (Li + Na + K + Alkaline earth ions that co-substitute at the A-site can synthesize perovskite-structured Li. 0.5 La 0.5 TiO3. The ABO3-type simple cubic perovskite structure consists of a series of shared oxygen octahedra. B-site ions with higher valence and smaller radius are located at the center of the oxygen octahedra, such as Ti, Sn, Zr, Nb, Ta, and W. Within the oxygen octahedra are A-site ions with larger radius, lower valence, and a coordination number of 12, such as Na, K, Rb, Ca, Sr, Ba, and Pb. Perovskite oxide electrolytes exhibit excellent chemical stability, do not react with the negative electrode, and ensure interfacial stability; they also possess excellent ionic conductivity and low electronic conductivity, enabling rapid migration of lithium ions within the electrolyte, reducing lithium ion accumulation on the negative electrode surface, and thus inhibiting lithium dendrite growth; and they possess excellent mechanical properties, ensuring structural stability and suppressing dendrite growth. Using this material as the negative electrode buffer layer 4 allows for good compatibility between the solid electrolyte film and the negative electrode sheet 5.
[0035] According to an embodiment of this utility model, the thickness of the positive electrode buffer layer 2 is 100nm-1000nm. For example, it can be 100nm, 300nm, 500nm, 700nm, 900nm, 1000nm, etc. Thus, by controlling the thickness of the positive electrode buffer layer 2 within the above range, the solid electrolyte film not only has excellent compatibility and good mechanical properties with the positive electrode 1, but also avoids being too thick, which would increase the lithium ion transport path and cause excessive internal resistance.
[0036] According to embodiments of this invention, the NASICON-type oxide electrolyte comprises either lithium aluminum titanium phosphate (LATP) or lithium aluminum germanium phosphate (LAGP). Preferably, the NASICON-type oxide electrolyte comprises lithium aluminum titanium phosphate (LATP). The NASICON-type oxide electrolyte formed from the above materials has a stable three-dimensional channel structure, providing good ion channels, thereby achieving efficient charge transfer and good interfacial contact; it has good chemical stability, is not prone to chemical reaction with the positive electrode material, has good mechanical properties, ensuring structural stability, and has a wide electrochemical window. Using this material as the positive electrode buffer layer 2 can achieve good compatibility between the solid electrolyte film and the positive electrode 1, thereby achieving a balance between the ionic conductivity and stability of the solid electrolyte film.
[0037] It is understood that the lithium aluminum titanium phosphate may include Li 1.3 Al x1 M1 y1 Ti 2-x1-y1 (PO4)3, M1 includes one or more of Ge, Zn, Mg, Ca, Sr, Si, and Sn, x1 = 0.2-0.6, y1 = 0-1; lithium aluminum germanium phosphate includes Li 1.3 Al x2 M2 y2 Ge 2-x2-y2 (PO4)3, M2 includes one or more of Al, Zn, Mg, Ca, Sr, Si, and Sn, x2 = 0.2-0.6, y2 = 0-1.
[0038] According to some embodiments of this utility model, the total number of layers of the glassy oxide electrolyte layer 31 and the garnet oxide electrolyte layer 32 is 2 to 50 layers. For example, the total number of layers can be 2, 5, 10, 30, 50, etc. By controlling the total number of alternatingly stacked glassy oxide electrolyte layers 31 and garnet oxide electrolyte layers 32 within the above range, the excellent ionic conductivity of the garnet oxide electrolyte and the flexibility and low electronic conductivity of the glassy oxide electrolyte can be amplified. This allows the overall thin film structure to have higher conductivity, better strain resistance, and better structural stability, thereby achieving a balance between the ionic conductivity and stability of the solid electrolyte thin film.
[0039] Please see Figure 2 Taking a total of 8 layers of glassy oxide electrolyte layer 31 and garnet oxide electrolyte layer 32 as an example, the glassy oxide electrolyte layer 31 and garnet oxide electrolyte layer 32 are stacked alternately to form 8 layers, so as to form lithium ion fast conduction layer 3.
[0040] According to some embodiments of this utility model, the thickness of the lithium-ion fast conduction layer 3 is 200nm-5000nm. For example, it can be 200nm, 500nm, 1000nm, 5000nm, etc. Controlling the thickness of the lithium-ion fast conduction layer 3 within the above range facilitates the rapid transport of lithium ions in the solid electrolyte film, enabling the overall solid electrolyte film to have higher conductivity, better strain resistance, and better structural stability.
[0041] According to some embodiments of this utility model, the thickness of a single glassy oxide electrolyte layer 31 is 100nm-200nm. For example, it can be 100nm, 150nm, 200nm, etc. Controlling the thickness of a single glassy oxide electrolyte layer 31 within the above range can further improve interfacial transport, thereby further improving the overall ion conduction efficiency.
[0042] According to some embodiments of this utility model, the thickness of a single garnet-type oxide electrolyte layer 32 is 100nm-200nm. For example, it can be 100nm, 150nm, 200nm, etc. Controlling the thickness of a single garnet-type oxide electrolyte layer 32 within the above range can improve the chemical and structural stability of the solid electrolyte film, thereby achieving a balance between the ionic conductivity and stability of the solid electrolyte film.
[0043] According to some embodiments of this utility model, the glassy oxide electrolyte layer 31 includes any one of LiPON and LiSiPON. The glassy oxide material described above possesses flexibility, which helps alleviate stress changes during battery charging and discharging. Its low electronic conductivity can also effectively suppress the occurrence of side reactions, further contributing to achieving a balance between ionic conductivity and stability in the solid electrolyte film.
[0044] It is understood that in this embodiment of the invention, "modified material" refers to material modification such as element doping and surface coating. Element doping can involve elements such as Fe, Mn, Al, and Si, and can be one or more dopants. Coating materials can include Al2O3, TiO2, C, and Si, and can also be one or more coatings. In this embodiment of the invention, when modifying the material of the glassy oxide electrolyte layer, it can be a modified LiPON or a modified LiSiPON, and so on below.
[0045] According to some embodiments of this utility model, the garnet-type oxide electrolyte layer 32 comprises lithium lanthanum zirconium oxide, with the general formula: Li7La3Zr 2-y3 M3 y3 O 12 M3 includes one or more of Ta, Nb, Ge, Mo, W, Hf, Sn, and Mn, and y3 = 0-1.5. The garnet-type oxide electrolyte layer 32 of the above materials has high ionic conductivity, can dominate ion transport and provide a fast channel, promote the efficient migration of lithium ions, and can improve the ionic conductivity of solid electrolyte films.
[0046] According to some embodiments of this utility model, the perovskite oxide electrolyte includes lithium lanthanum titanium oxide, and the general formula can be: Li x4 La y4 M4 z4 TiO3, where M4 includes one or more of Ce, Pr, Y, Sc, Nd, Sm, Eu, and Gd, with x4 = 0.2-0.8, y4 = 0.3-0.6, and z4 = 0-0.5. In the crystal structure of LLTO, LLTO belongs to the cubic crystal system with space group Pm-3m. Titanium ions and oxygen ions constitute the octahedral structure of TiO6, while lithium ions and lanthanum ions are located in the interstices formed by the eight vertices connected to the same apex of TiO6. + There are 12 O's around it 2-The perovskite oxide electrolyte exhibits excellent chemical stability, does not react with the negative electrode, and ensures interfacial stability; it also possesses excellent ionic conductivity and low electronic conductivity, enabling rapid migration of lithium ions within the electrolyte and reducing lithium ion accumulation on the negative electrode surface, thereby inhibiting lithium dendrite growth; and it has excellent mechanical properties, ensuring structural stability and suppressing dendrite growth. Using this material as the negative electrode buffer layer 4 achieves good compatibility between the solid electrolyte film and the negative electrode sheet 5.
[0047] According to some embodiments of this utility model, the thickness of the negative electrode buffer layer 4 is 100nm-1000nm. For example, the thickness of the negative electrode buffer layer 4 can be 100nm, 200nm, 500nm, 800nm, 10000nm, etc. Thus, by controlling the thickness of the negative electrode buffer layer 4 within the above range, the solid electrolyte film not only has excellent compatibility and good mechanical properties with the negative electrode, suppressing the growth of negative electrode dendrites, but also avoids excessive thickness that would increase the lithium ion transport path and cause excessive internal resistance.
[0048] According to some embodiments of the present invention, each layer of the solid electrolyte film can be prepared using conventional methods in the art, such as magnetron sputtering for each layer or casting for each layer.
[0049] As an example, when using magnetron sputtering, the sputtering power of the positive electrode buffer layer 2 is 80W-150W, the atmosphere is Ar, the pressure is 1Pa-2Pa, the substrate temperature is 0℃-500℃, the target material composition is LATP or LAGP, and the distance between the target material and the substrate is 5cm-10cm.
[0050] The sputtering power of the glassy oxide electrolyte layer 31 in the lithium-ion fast conduction layer 3 is 40W-150W, the atmosphere is Ar / N2, the flow ratio of Ar to N2 is 1:1-10:1, the gas pressure is 1Pa-2Pa, the substrate temperature is 0℃-400℃, the target material composition is Li3PO4 or Li3PO4 / Si3N4, and the distance between the target material and the substrate is 5cm-10cm.
[0051] The sputtering power of the garnet-type oxide electrolyte layer 32 in the lithium-ion fast conduction layer 3 is 40W-150W, the atmosphere is Ar, the gas pressure is 1Pa-2Pa, the substrate temperature is 0℃-500℃, the target material is LLZO, and the distance between the target material and the substrate is 5cm-10cm.
[0052] The sputtering power of the negative electrode buffer layer 4 is 80W-150W, the atmosphere is Ar, the pressure is 1Pa-2Pa, the substrate temperature is 0℃-400℃, the target material composition is LLTO, and the distance between the target material and the substrate is 5cm-10cm.
[0053] In a second aspect, the present invention provides a solid-state battery, the solid-state battery comprising the solid electrolyte film described in the first aspect of the present invention.
[0054] Please see Figure 3 The solid-state battery comprises a positive electrode 1, a solid electrolyte film as described in the first aspect of this invention, and a negative electrode 5, stacked sequentially. The positive electrode 1 is in contact with the positive electrode buffer layer 2, and the negative electrode 5 is in contact with the negative electrode buffer layer 4. Therefore, the solid-state battery of this invention exhibits excellent ionic conductivity and cycle performance.
[0055] Typically, a battery consists of a positive electrode, a negative electrode, and a solid electrolyte film. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and extracting. The solid electrolyte film acts as a conductor of ions between the positive and negative electrodes.
[0056] Typically, a positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one side surface of the positive current collector, wherein the positive active material layer includes a positive active material.
[0057] In some embodiments of this application, the positive electrode current collector may include a metal foil or a composite positive electrode current collector. For example, the metal foil may be aluminum foil. The composite positive electrode current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. For example, the composite positive electrode current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.).
[0058] As an example, the positive electrode active material includes, but is not limited to, at least one of metal oxide positive electrode active materials, polyanionic positive electrode active materials, transition metal positive electrode active materials, and organic positive electrode active materials.
[0059] As an example, the metal oxide cathode active materials include, but are not limited to, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum ternary materials, lithium-rich manganese-based materials, lithium manganese oxide (LiMn2O4), and lithium nickel-manganese oxide (LiNi). 0.5 Mn 1.5 At least one of O4, iron(III) oxide (Fe3O4), and lithium vanadate.
[0060] As an example, the polyanionic cathode active material includes, but is not limited to, at least one of lithium iron phosphate (LiFePO4), lithium manganese phosphate (LiMnPO4), lithium manganese iron phosphate, lithium vanadium phosphate (Li3V2(PO4)3), lithium vanadium oxyphosphate (LiVOPO4), lithium cobalt phosphate (LiCoPO4), lithium nickel phosphate (LiNiPO4), lithium iron silicate (Li2FeSiO4), lithium iron fluorosulfate (LiFeSO4F), lithium iron borate (LiFeBO3), and lithium iron titanate (Li2FeTiO4).
[0061] As an example, the transition metal cathode active material includes, but is not limited to, at least one of iron trifluoride (FeF3), cobalt trifluoride (CoF3), nickel trifluoride (NiF3), titanium disulfide (TiS2), iron disulfide (FeS2), molybdenum disulfide (MoS2), and niobium triselenide (NbSe3).
[0062] As an example, the organic positive electrode active material includes, but is not limited to, at least one of quinone-based organic materials and nitrogen-containing organic materials.
[0063] As an example, the quinone molecular organic material includes at least one of benzoquinone, anthraquinone, phenanthrenequinone, dithiophenebenzoquinone, dipyridinobenzoquinone, difuranobenzoquinone, lithium 2,6-dicarboxylate anthraquinone, lithium 2,7-dicarboxylate phenanthrenequinone, and lithium 2,7-dicarboxylate pyrene-4,5,9,10-tetraone.
[0064] As an example, the nitrogen-containing organic material includes, but is not limited to, at least one of pteridine, phenolazine, pteridine derivatives and phenolazine derivatives.
[0065] According to some embodiments of the present invention, the positive electrode active material layer may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
[0066] According to some embodiments of the present invention, the positive electrode active material layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.
[0067] According to some embodiments of the present invention, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, and binder, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
[0068] The negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one side surface of the negative current collector, wherein the negative active material layer includes a negative active material.
[0069] According to some embodiments of this utility model, the negative electrode current collector can be a metal foil or a composite current collector. For example, copper foil can be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.).
[0070] According to some embodiments of the present invention, the negative electrode active material includes, but is not limited to, at least one of graphite, graphene, soft carbon, hard carbon, elemental silicon, silicon-oxygen materials, silicon-carbon materials, silicon-nitrogen composite materials, silicon-based alloys, elemental tin, tin oxides, tin-based alloys, lithium metal, lithium alloys, lithium titanium oxides, transition metal oxides, and transition metal sulfides.
[0071] According to some other embodiments of this application, the negative electrode comprises lithium metal. Therefore, the solid-state battery exhibits excellent specific capacity, and the lithium metal of the negative electrode has good compatibility with the perovskite oxide electrolyte of the negative electrode buffer layer, thus better balancing the ionic conductivity and stability of the solid-state battery.
[0072] According to some embodiments of the present invention, the negative electrode active material layer may optionally include a binder. The binder may include at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).
[0073] According to some embodiments of this invention, the negative electrode active material layer may optionally include a conductive agent. The conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
[0074] According to some embodiments of the present invention, the negative electrode active material layer may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).
[0075] According to some embodiments of this utility model, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
[0076] When the electrolyte is solid, the electrolyte includes solid electrolytes and lithium salts.
[0077] According to some embodiments of the present invention, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium bis(oxalate)borate, lithium difluorooxalateborate, lithium difluorooxalate phosphate, lithium tetrafluorooxalate phosphate, and lithium bis(trifluoromethanesulfonyl)imide.
[0078] The present disclosure will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the disclosure. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.
[0079] Example 1
[0080] A positive electrode buffer layer, a lithium-ion fast conduction layer, and a negative electrode buffer layer were sequentially constructed on a Si substrate using magnetron sputtering. The distance between the target and the Si substrate in the magnetron sputtering equipment was 7 cm. The specific process was as follows: the sputtering power for depositing the positive electrode buffer layer on the Si substrate was 80 W, the atmosphere was Ar, the pressure was 1 Pa, the substrate temperature was 300 °C, and the target material was LATP (chemical formula Li). 1.3 Al 0.3 Ti 1.7 (PO4)3), with a deposition thickness of 500 nm; when constructing a lithium-ion fast conduction layer on the positive electrode buffer layer, LiPON and LLZO (chemical formula Li7La3Zr2O) were deposited alternately by magnetron sputtering. 12The system consists of 20 layers with a total deposition thickness of 2000 nm. Each LiPON layer is 100 nm thick, and each LLZO layer is 100 nm thick. The sputtering power for LiPON deposition was 80 W, the atmosphere was Ar / N2 with a flow ratio of 5:1, the pressure was 1 Pa, the substrate temperature was 300 °C, and the target material was Li3PO4. The sputtering power for LLZO deposition was 40 W, the atmosphere was Ar, the pressure was 1 Pa, the substrate temperature was 300 °C, and the target material was LLZO. The sputtering power for depositing the negative electrode buffer layer on the lithium-ion fast conduction layer was 100 W, the atmosphere was Ar, the pressure was 1 Pa, the substrate temperature was 300 °C, and the target material was LLTO (chemical formula Li). 0.5 La 0.5 TiO3 was deposited to a thickness of 500 nm, resulting in a solid electrolyte film.
[0081] Example 2
[0082] Except for the construction of the lithium-ion fast conduction layer on the positive electrode buffer layer, in which 40 layers of LiPON and LLZO were alternately deposited by magnetron sputtering with a deposition thickness of 4000 nm, the rest of the preparation process and structure were the same as in Example 1.
[0083] Example 3
[0084] Except when depositing the positive electrode buffer layer, the target material is LAGP (chemical formula Li). 1.3 Al 0.3 Ge 1.7 (PO4)3), the rest of the preparation process and structure are the same as in Example 1.
[0085] Example 4
[0086] Except for replacing the glassy oxide electrolyte layer component LiPON with LiSiPON and the target component Li3PO4 with Li3PO4 / Si3N4 during deposition, the rest of the preparation process and structure are the same as in Example 1.
[0087] Comparative Example 1
[0088] The difference from Example 1 is that no positive electrode buffer layer is deposited.
[0089] Comparative Example 2
[0090] The difference from Example 1 is that no negative electrode buffer layer is deposited.
[0091] Comparative Example 3
[0092] The difference from Example 1 is that no positive and negative electrode buffer layers are deposited.
[0093] Comparative Example 4
[0094] The difference from Example 1 is that only LiPON is deposited in the lithium-ion fast conduction layer.
[0095] Comparative Example 5
[0096] The difference from Example 1 is that only LLZO is deposited in the lithium-ion fast conduction layer.
[0097] The solid electrolyte films of Examples 1-4 and Comparative Examples 1-5 were respectively composited with positive and negative electrode sheets, wherein...
[0098] Preparation of positive electrode: The positive electrode active material NCM811 (LiNi) is prepared. 0.8 Co 0.1 Mn 0.1 O2), conductive agent conductive carbon black, and binder polyvinylidene fluoride are dissolved in N-methylpyrrolidone. The positive electrode active material: conductive agent: binder mass ratio is 96:2:2. The mixture is then coated on the surface of the current collector, dried, and rolled to obtain the positive electrode sheet.
[0099] Negative electrode preparation: Lithium metal with a thickness of 200 μm was used as the negative electrode.
[0100] Solid-state battery preparation: Assemble the above-obtained negative electrode, solid electrolyte film, and positive electrode into a battery, and heat-press them together to obtain a solid-state battery.
[0101] Testing and Analysis
[0102] Under the same conditions, the solid-state batteries prepared in the above embodiments and comparative examples were subjected to the following tests, and the specific test methods are as follows:
[0103] Ionic conductivity determination: Measurement was performed using AC impedance spectroscopy. The test system was assembled into a stainless steel | solid electrolyte | stainless steel battery. AC impedance spectroscopy was used on a CHI660D electrochemical workstation with a frequency range of 1Hz-10MHz, an AC amplitude of 5mV, and a test temperature of 25℃. Each test was performed three times, and the average value was taken. The ionic conductivity (σ) was calculated using the following formula: σ=d / (R*S). Where d is the thickness of the electrolyte, R is the measured resistance value, and S is the area of the electrolyte film.
[0104] Battery capacity retention test after 200 cycles: The prepared solid-state battery was tested on a NEWARE battery charge-discharge instrument at a test temperature of 25℃ and a current of 1C for 200 cycles, and the capacity retention rate was recorded.
[0105] The test results are shown in Table 1.
[0106] Table 1
[0107] Ionic conductivity (S / cm) Capacity retention Example 1 <![CDATA[1.3×10 -5 ]]> 94.6％ Example 2 <![CDATA[8.9×10 -6 ]]> 92.2％ Example 3 <![CDATA[9.2×10 -6 ]]> 93.4％ Example 4 <![CDATA[1.2×10 -5 ]]> 94.1％ Comparative Example 1 <![CDATA[8.5×10 -6 ]]> 91.4％ Comparative Example 2 <![CDATA[8.4×10 -6 ]]> 89.1％ Comparative Example 3 <![CDATA[8.2×10 -6 ]]> 84.9％ Comparative Example 4 <![CDATA[3.2×10 -6 ]]> 91.6％ Comparative Example 5 <![CDATA[8.6×10 -6 ]]> 75.3％
[0108] As shown in Table 1, the solid electrolyte film of this application exhibits excellent ionic conductivity, and the solid-state battery containing it demonstrates excellent cycle performance. In contrast, Comparative Examples 1-5, which do not employ the solid electrolyte film of this application, show significantly reduced ionic conductivity and cycle performance of their solid-state batteries. Therefore, the solid electrolyte film provided by this invention can balance ionic conductivity and stability.
[0109] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," "some implementations," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0110] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. A solid electrolyte thin film, characterized in that, The solid electrolyte film comprises a positive electrode buffer layer, a lithium-ion fast conduction layer, and a negative electrode buffer layer stacked sequentially, wherein... The positive electrode buffer layer includes a NASICON-type oxide electrolyte; The lithium-ion fast conduction layer includes alternating layers of glassy oxide electrolyte layer and garnet-type oxide electrolyte layer; The negative electrode buffer layer includes a perovskite oxide electrolyte.
2. The solid electrolyte film according to claim 1, characterized in that, The NASICON-type oxide electrolyte includes either lithium aluminum titanium phosphate or lithium aluminum germanium phosphate.
3. The solid electrolyte film according to claim 1, characterized in that, The NASICON-type oxide electrolyte includes lithium aluminum titanium phosphate; and / or, The thickness of the positive electrode buffer layer is 100nm-1000nm.
4. The solid electrolyte film according to claim 1, characterized in that, The total number of the glassy oxide electrolyte layer and the garnet-type oxide electrolyte layer is 2 to 50 layers; and / or, The thickness of the lithium-ion fast conduction layer is 200nm-5000nm.
5. The solid electrolyte film according to claim 1, characterized in that, The thickness of a single glassy oxide electrolyte layer is 100 nm-200 nm; and / or, The thickness of a single garnet-type oxide electrolyte layer is 100nm-200nm.
6. The solid electrolyte thin film according to claim 1, characterized in that, The glassy oxide electrolyte layer includes any one of LiPON and LiSiPON; and / or, The garnet-type oxide electrolyte layer comprises lithium lanthanum zirconium oxide.
7. The solid electrolyte thin film according to any one of claims 1-6, characterized in that, The perovskite-type oxide electrolyte includes lithium lanthanum titanium oxide.
8. The solid electrolyte film according to any one of claims 1-6, wherein the thickness of the negative electrode buffer layer is 100nm-1000nm.
9. A solid-state battery, characterized in that, The solid-state battery includes a positive electrode, a solid electrolyte film according to any one of claims 1-8, and a negative electrode stacked sequentially, wherein the positive electrode is in contact with the positive electrode buffer layer, and the negative electrode is in contact with the negative electrode buffer layer.
10. The solid-state battery according to claim 9, characterized in that, The negative electrode sheet comprises lithium metal.