An integrated electrode and a preparation method and application thereof

Abstract

The application discloses an integrated electrode and a preparation method and application thereof, wherein the preparation method comprises the following steps: uniformly mixing a positive electrode active material, LiOH and a metal conductive agent, and then press-forming into a sheet to obtain a positive electrode sheet; uniformly mixing one or more of oxide solid electrolytes and LiOH, and then press-forming into a sheet to obtain an electrolyte sheet; uniformly mixing a negative electrode active material and a metal conductive agent, and then press-forming into a product to obtain a negative electrode sheet; sequentially stacking the positive electrode sheet, the electrolyte sheet and the negative electrode sheet, and then performing cold isostatic pressing treatment to obtain a mixed stack; and performing sintering treatment on the mixed stack in an oxygen atmosphere to obtain the integrated electrode. The integrated electrode prepared by the application greatly eliminates the interface problems existing in traditional oxide battery materials and the influence of glue in the electrode on the impedance of the battery, and the integrated electrode has high compactness and higher energy density; and the integrated electrode is used for preparing a solid battery, so that the rate and cycle performance of the battery can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of battery electrode technology, and in particular to an integrated electrode, its preparation method, and its application. Background Technology

[0002] With the energy revolution, global communications have accelerated. Currently, lithium batteries show broad application prospects in electric vehicles, hybrid vehicles, and smart grids. However, traditional liquid lithium batteries have low energy density and contain large amounts of flammable and explosive organic electrolytes, posing significant challenges to their safety performance. Solid-state batteries, as a new generation of lithium batteries, greatly improve battery safety while reducing the use of separators and significantly increasing energy density.

[0003] Currently, there are three main directions for promising solid-state electrolytes: inorganic sulfide solid electrolytes, inorganic oxide solid electrolytes, and polymer solid electrolytes. However, polymers are organic materials, and sulfides react upon contact with air, posing significant safety risks. Furthermore, polymer and sulfide solid electrolytes have narrow electrochemical windows, hindering the application of high-voltage cathode materials. Traditional oxide solid-state battery fabrication methods involve coating oxides onto the positive and negative electrode surfaces or pressing oxides into sheets. This approach not only reduces the battery's energy density but also results in low material density and high interfacial impedance, significantly impacting the battery's electrical performance.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide an integrated electrode, its preparation method and application, in order to solve the problem of poor battery performance in existing solid-state batteries due to poor electrolyte density and large interfacial impedance between the electrolyte and the electrode.

[0006] The technical solution of the present invention is as follows:

[0007] A method for fabricating an integrated electrode, comprising the steps of:

[0008] After the positive electrode active material is mixed evenly with LiOH and a metal conductive agent, it is pressed into a sheet to obtain the positive electrode sheet;

[0009] One or more oxide solid electrolytes are mixed evenly with LiOH and then pressed into sheets to obtain electrolyte sheets;

[0010] After the negative electrode active material is mixed evenly with the metal conductive agent, the finished product is pressurized to obtain the negative electrode sheet.

[0011] Stack the positive electrode sheet, electrolyte sheet, and negative electrode sheet in sequence, and after cold isostatic pressing treatment, a mixed laminated sheet is obtained;

[0012] Perform sintering treatment on the mixed laminated sheet in an oxygen atmosphere to obtain an integrated electrode.

[0013] The preparation method of the integrated electrode, wherein the positive electrode active material is Ni x Co y Mn (1-x-y) OH2, where 0 < x < 1, 0 < y < 1 and 0 < x + y < 1.

[0014] The preparation method of the integrated electrode, wherein the metal conductive agent is a Pt metal conductive agent or a Pd metal conductive agent.

[0015] The preparation method of the integrated electrode, wherein the oxide solid electrolyte is one or more of perovskite-type electrolyte, inverse perovskite-type electrolyte, garnet-type electrolyte, NASICON-type electrolyte, and LISICON-type electrolyte.

[0016] The preparation method of the integrated electrode, wherein the negative electrode active material is SiO x 、TiO2、WO3、Li4Ti5O 12 and one or more of Li3VO4.

[0017] The preparation method of the integrated electrode, wherein in the step of performing sintering treatment on the mixed laminated sheet in an oxygen atmosphere, the sintering temperature is 700 - 900 °C.

[0018] An integrated electrode, wherein it is prepared by using the preparation method of the present invention.

[0019] An application of an integrated electrode, wherein the integrated electrode of the present invention is used to prepare a solid battery.

[0020] Beneficial effects: The present invention forms an integrated electrode by high-temperature co-sintering after laminating the positive electrode sheet, electrolyte sheet, and negative electrode sheet. The integrated electrode greatly eliminates the interface problems existing in traditional oxide battery materials and the influence of glue in the electrode on the battery impedance, and the integrated electrode has high density and higher energy density; using the integrated electrode to prepare a solid battery can effectively improve the rate and cycle performance of the battery. Brief Description of the Drawings

[0021] Figure 1 It is a flowchart of the preparation method of an integrated electrode of the present invention. Detailed Embodiments

[0022] The present invention provides an integrated electrode, a preparation method thereof and an application thereof. To make the objectives, technical solutions and effects of the present invention clearer and more definite, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] Please refer to Figure 1 , Figure 1 which is a flowchart of a preparation method of an integrated electrode provided by the present invention. As shown in the figure, it includes the steps:

[0024] S10. After uniformly mixing a positive electrode active material, LiOH and a metal conductive agent, pressing them into a sheet to obtain a positive electrode sheet;

[0025] S20. After uniformly mixing one or more of oxide solid electrolytes with LiOH, pressing them into a sheet to obtain an electrolyte sheet;

[0026] S30. After uniformly mixing a negative electrode active material and a metal conductive agent, pressing them into a finished product to obtain a negative electrode sheet;

[0027] S40. Stacking the positive electrode sheet, the electrolyte sheet and the negative electrode sheet in sequence, and after cold isostatic pressing treatment, obtaining a mixed stack;

[0028] S50. Sintering the mixed stack in an oxygen atmosphere to obtain an integrated electrode.

[0029] Specifically, traditional solid-state batteries mostly adopt the method of making solid electrolytes into thin films or making slurries and coating them on the surfaces of positive and negative electrodes. This process results in poor densification of the solid electrolyte, and large interfacial impedance between electrolyte - electrolyte and electrolyte - electrode materials, which is not conducive to ion conduction. In this embodiment, by stacking the positive electrode sheet, the electrolyte sheet and the negative electrode sheet and forming an integrated electrode through high-temperature co-sintering, the integrated electrode greatly eliminates the interfacial problems existing in traditional oxide battery materials and the influence of glue in the electrode on the battery impedance, and the integrated electrode has high densification and higher energy density; using the integrated electrode to prepare a solid battery can effectively improve the rate and cycle performance of the battery.

[0030] In some embodiments, the positive electrode active material is Ni x Co y Mn (1-x-y) OH2, where 0 < x < 1, 0 < y < 1 and 0 < x + y < 1.

[0031] In some embodiments, the metal conductive agent is a Pt metal conductive agent or a Pd metal conductive agent.

[0032] In some embodiments, the oxide solid electrolyte is one or more of perovskite-type electrolyte, inverse perovskite-type electrolyte, garnet-type electrolyte, NASICON-type electrolyte, and LISICON-type electrolyte, but not limited thereto. By way of example, the perovskite-type electrolyte is Li3 x La 2 / 3-x TiO3, where 0.04 < x; the garnet-type electrolyte is selected from doped or undoped lithium lanthanum zirconium oxide electrolyte, where the doping element is selected from at least one of Al, Ga, Fe, Ge, Ca, Ba, Sr, Y, Nb, Ta, W, Sb elements; preferably, the garnet-type electrolyte is selected from Li 7-m La3Zr 2-m Ta m O 12 (0 ≤ m ≤ 0.6), Li 7-y La3Zr 2-y Nb y O 12 (0 ≤ y ≤ 0.6) and Li 6.4-p La3Zr 2-p Ta p Al 0.2 O 12 (0.2 ≤ p ≤ 0.5) of at least one; the NASICON-type electrolyte is selected from Li 1+x Ti 2-x M x (PO4)3, Li 1+x Ge 2-x M x (PO4)3 of at least one, where 0.2 ≤ x ≤ 0.5, 0.2 ≤ x ≤ 0.5, M = Al, Cr, Ga, Fe, Sc, In, Lu, Y or La; more preferably, selected from Li 1+x Ti 2- x Al x (PO4)3 (LATP) or Li 1+x Ge 2-x Al x (PO4)3 (LAGP) of at least one, where 0.2 ≤ x ≤ 0.5, 0.4 ≤ x ≤ 0.5. Where, the LISICON-type electrolyte is Li 4-r Ge 1-r PrS4 (0.3 < r < 0.7, for example 0.4 or 0.6).

[0033] In some embodiments, the negative electrode active material is SiO x 、TiO2、WO3、Li4Ti5O 12 and Li3VO4 one or more of, but not limited thereto.

[0034] In some embodiments, the sintering temperature is 700-900°C during the step of sintering the mixed stack in an oxygen atmosphere.

[0035] In some embodiments, an integrated electrode is also provided, which is prepared using the preparation method described in this invention.

[0036] In some embodiments, an application of the integrated electrode is also provided, wherein the integrated electrode of the present invention is used to prepare a solid-state battery.

[0037] The present invention will be further explained and illustrated below through specific embodiments:

[0038] Example 1

[0039] Step 1: Composite cathode configuration: Ni 0.8 Co 0.1 Mn 0.1 (OH)2:LiOH (molar ratio 1:1) and 5% metal conductive agent are mixed evenly and then pressed into sheets;

[0040] Step 2: Preparation of electrolyte (LATP): Mix NH4H2PO4:Al2O3:TiO2:LiOH (molar ratio 3:0.3:1.7:1.3) evenly and press into tablets;

[0041] Step 3: Negative electrode configuration: Li4Ti5O 12 Mix 5% of the metal conductive agent evenly and press it into sheets;

[0042] Step 4: Stack the sheet-like samples in the order of composite positive electrode / electrolyte / negative electrode mixture, and then compact them by cold isostatic pressing;

[0043] Step 5: Place the sample sheet pressed into a sheet in Step 4 into a dry pot or quartz tube and sinter it at 800℃ with the addition of oxygen to obtain a highly dense integrated electrode-electrolyte electrode.

[0044] Step 6: Plate metal electrodes onto the positive and negative electrodes of the integrated electrode-electrolyte obtained in Step 5 to obtain an integrated battery.

[0045] Example 2

[0046] Step 1: Composite cathode configuration: Ni 0.8 Co 0.1 Mn 0.1 (OH)2:LiOH (molar ratio 1:1), metal conductive agent with a metal conductivity of 5%, are mixed evenly and then pressed into sheets;

[0047] Step 2: Electrolyte (LLZO) preparation: Mix La2O3:ZrO2:LiOH (molar ratio 1.5:2:7) evenly and press into sheets;

[0048] Step 3: Negative electrode configuration: Li4Ti5O 12 Mix 5% of the metal conductive agent evenly and press it into sheets;

[0049] Step 4: Stack the sheet-like samples in the order of composite positive electrode / electrolyte / negative electrode mixture, and then compact them by cold isostatic pressing;

[0050] Step 5: Place the sample sheet pressed into a sheet in Step 4 into a dry pot or quartz tube and sinter it at 800℃ with the addition of oxygen to obtain a highly dense integrated electrode-electrolyte electrode.

[0051] Step 6: Plate metal electrodes onto the positive and negative electrodes of the integrated electrode-electrolyte obtained in Step 5 to obtain an integrated battery.

[0052] Example 3

[0053] Step 1: Composite cathode configuration: Ni 0.8 Co 0.1 Mn 0.1 (OH)2:LiOH (molar ratio 1:1) and 5% metal conductive agent are mixed evenly and then pressed into sheets;

[0054] Step Two: Electrolyte (LATP) Preparation: Mix NH4H2PO4:Al2O3:TiO2:LiOH (molar ratio 3:0.3:1.7:1.3) evenly and press into tablets;

[0055] Step 3: Negative electrode configuration: SiO x Mix 5% of the metal conductive agent evenly and press it into sheets;

[0056] Step 4: Stack the sheet-like samples in the order of composite positive electrode / electrolyte / negative electrode mixture, and then compact them by cold isostatic pressing;

[0057] Step 5: Place the sample sheet pressed into a sheet in Step 4 into a dry pot or quartz tube and sinter it at 800℃ with the addition of oxygen to obtain a highly dense integrated electrode-electrolyte electrode.

[0058] Step 6: Plate metal electrodes onto the positive and negative electrodes of the integrated electrode-electrolyte obtained in Step 5 to obtain an integrated battery.

[0059] Example 4

[0060] Step 1: Composite cathode configuration: Ni 0.7 Co 0.1 Mn 0.2(OH)2:LiOH (molar ratio 1:1) and 5% metal conductive agent are mixed evenly and then pressed into sheets;

[0061] Step 2: Electrolyte (LLZO) preparation: Mix La2O3:ZrO2:LiOH (molar ratio 1.5:2:7) evenly and press into sheets;

[0062] Step 3: Negative electrode preparation: SiOx and metal conductive agent at a ratio of 5% are mixed evenly and pressed into sheets;

[0063] Step 4: Stack the sheet-like samples in the order of composite positive electrode / electrolyte / negative electrode mixture, and then compact them by cold isostatic pressing;

[0064] Step 5: Place the sample sheet pressed into a sheet in Step 4 into a dry pot or quartz tube and sinter it at 700°C with the addition of oxygen to obtain a highly dense integrated electrode-electrolyte electrode.

[0065] Step 6: Plate metal electrodes onto the positive and negative electrodes of the integrated electrode-electrolyte obtained in Step 5 to obtain an integrated battery.

[0066] Example 5

[0067] Step 1: Composite cathode configuration: Ni 0.6 Co 0.2 Mn 0.2 (OH)2:LiOH (molar ratio 1:1) and 5% metal conductive agent are mixed evenly and then pressed into sheets;

[0068] Step 2: Electrolyte (LLZO) preparation: Mix La2O3:ZrO2:LiOH (molar ratio 1.5:2:7) evenly and press into sheets;

[0069] Step 3: Negative electrode preparation: Li3VO4 and metal conductive agent at a ratio of 5% are mixed evenly and pressed into sheets;

[0070] Step 4: Stack the sheet-like samples in the order of composite positive electrode / electrolyte / negative electrode mixture, and then compact them by cold isostatic pressing;

[0071] Step 5: Place the sample sheet pressed into a sheet in a dry pot or quartz tube and sinter it at 900℃ with the addition of oxygen to obtain a highly dense integrated electrode-electrolyte electrode.

[0072] Step 6: Plate metal electrodes onto the positive and negative electrodes of the integrated electrode-electrolyte obtained in Step 5 to obtain an integrated battery.

[0073] Comparative Example 1

[0074] Step 1: Composite cathode configuration: Mix NCM811:SP:LLZO:PVDF (mass ratio 90:5:3:2) evenly, coat it on aluminum foil, and roll it to form an electrode sheet;

[0075] Step 2: Electrolyte preparation: LLZO:PVDF (mass ratio 96:4) is mixed into a slurry and uniformly coated on the positive electrode surface;

[0076] Step 3: Negative electrode configuration: Place SiO... x SP:LLZO:PVDF (mass ratio 90:5:3:2) are mixed evenly and coated onto aluminum foil, then rolled to form electrode sheets.

[0077] Step 4: Stack the sheet-like samples in the order of oxide composite positive / composite negative electrode sheets, and then hot press them.

[0078] Step 5: Package the bare cells stacked in Step 4 to obtain an all-solid-state battery.

[0079] The performance of the solid-state batteries prepared in Comparative Example 1 and Examples 1-5 was tested, and the results are shown in Table 1.

[0080] Table 1. Solid-state battery performance test results

[0081]

[0082] As can be seen from the results in Table 1, compared with traditional composite solid-state batteries, the integrated solid-state battery prepared in the embodiments of the present invention has better rate performance and cycle performance.

[0083] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for fabricating an integrated electrode, characterized in that, Including the following steps: After uniformly mixing the positive electrode active material with LiOH and the metal conductive agent, press them into sheets to obtain the positive electrode sheets; the positive electrode active material is Ni x Co y Mn (1-x-y) OH2, where 0 < x < 1, 0 < y < 1 and 0 < x + y < 1; One or more oxide solid electrolytes are mixed evenly with LiOH and then pressed into sheets to obtain electrolyte sheets; After uniformly mixing the negative electrode active material with a metallic conductive agent, the mixture is pressurized to obtain the negative electrode sheet; the negative electrode active material is SiO2. x TiO2, WO3, Li4Ti5O 12 and one or more of Li3VO4; The positive electrode, electrolyte sheet, and negative electrode sheet are stacked sequentially and then subjected to cold isostatic pressing to obtain a mixed stack. The hybrid stack is sintered in an oxygen atmosphere at a temperature of 700-900℃ to obtain an integrated electrode.

2. The method for preparing the integrated electrode according to claim 1, characterized in that, The metal conductive agent is a Pt metal conductive agent or a Pd metal conductive agent.

3. The method for preparing the integrated electrode according to claim 1, characterized in that, The oxide solid electrolyte is one or more of the following: perovskite electrolyte, anti-perovskite electrolyte, garnet electrolyte, NASICON electrolyte, and LISICON electrolyte.

4. An integrated electrode, characterized in that, It is prepared by any one of the preparation methods described in claims 1-3.

5. An application of an integrated electrode, characterized in that, The integrated electrode described in claim 4 is used to prepare a solid-state battery.

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