A method of making and using a binder for high ionic conductivity and high voltage electrode materials

Abstract

The application relates to a preparation method and application of an electrode material binder with high ion conductivity and high-voltage resistance, wherein polyethylene oxide is dissolved in deionized water, stirred for 24 hours at room temperature, and a polyethylene oxide solution is prepared; lithium salt is added; a sodium carboxymethyl cellulose aqueous solution is mixed with the polyethylene oxide-lithium salt mixed solution, stirred for 12 hours at room temperature, and an electrode material binder is obtained; the electrode material binder is mixed with a high-voltage resistant additive, and a high-ion-conductivity and high-voltage-resistant electrode material binder is obtained. The positive electrode material prepared based on the electrode material binder with high ion conductivity and high-voltage resistance has high capacity and excellent cycle stability. The modified lithium-rich manganese-based positive electrode material prepared has high ion conductivity and high-voltage resistance, the discharge specific capacity of the modified lithium-rich manganese-based positive electrode material is up to 295.51 mAh / g or more, the capacity retention rate is 102.14% after 400 cycles, and the modified lithium-rich manganese-based positive electrode material has high capacity and high cycle stability.

Description

Technical Field

[0001] This invention relates to the technical field of lithium-ion batteries, and more particularly to a method for preparing and applying a binder with high ionic conductivity and high voltage resistance. Background Technology

[0002] In modern electronic devices and energy storage systems, adhesives are a critical component, playing a vital role in the performance and stability of the equipment. While traditional adhesives can meet basic requirements under certain conditions, they often perform poorly in high-voltage environments, prone to breakdown and failure, thus limiting the reliability and lifespan of the devices. This problem is particularly pronounced in electric vehicles, grid energy storage, and portable electronic devices, where these applications have extremely high requirements for high-voltage stability and long-term performance.

[0003] To address these limitations of traditional adhesives, researchers are actively exploring and developing novel adhesives with high ionic conductivity and high voltage resistance. These adhesives not only effectively transport electrons and ions but also maintain stability under high electric field conditions, thereby significantly improving device performance and reliability. High ionic conductivity enables the adhesive to effectively promote electron and ion transport, contributing to improved device efficiency and response speed; while high voltage resistance ensures that breakdown or damage does not occur under high voltage stress, extending device lifespan and stability.

[0004] The development of novel binders relies not only on the electrical and chemical properties of the materials themselves but also on the precise control of their composition and structure. Through rational design and process optimization, researchers can tailor binders to meet the specific needs of different application scenarios, thereby driving technological advancements and innovations in electronic devices and energy storage systems. For example, in lithium-ion batteries, optimized binders can improve the structural stability and electrochemical performance of electrode materials, thereby enhancing the battery's cycle life and energy density.

[0005] Overall, the development and application of binders with high ionic conductivity and high voltage resistance are not only technological challenges, but also key factors driving the development of electronic devices and energy storage. Future research will continue to focus on exploring new materials, optimizing processes, and innovating applications to meet the growing demand for high-performance and high-reliability devices. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention discloses a method for preparing an adhesive with high ionic conductivity and high voltage resistance. The prepared adhesive possesses both high ionic conductivity and excellent high voltage resistance.

[0007] The technical solution of this invention is:

[0008] A method for preparing an adhesive with high ionic conductivity and high voltage resistance includes the following steps:

[0009] Step 1: Prepare a polyethylene oxide-lithium salt mixture

[0010] Polyoxyethylene was dissolved in deionized water and stirred at room temperature for 24 hours to prepare a polyoxyethylene solution. Lithium salt was added at a mass ratio of 12:1 to polyoxyethylene to lithium salt to obtain a polyoxyethylene-lithium salt mixture.

[0011] Step 2: Preparation of electrode material binder

[0012] A sodium carboxymethyl cellulose aqueous solution and a polyethylene oxide-lithium salt mixture were mixed at a mass ratio of 10:1 and stirred at room temperature for 12 hours to obtain an electrode material binder.

[0013] Step 3: Preparation of a binder for electrode materials with high ionic conductivity and high voltage resistance

[0014] The electrode material binder and the high-voltage resistant additive are mixed at a mass ratio of 10:(0-1.5), wherein the high-voltage resistant additive is one or two of pentafluorophenylboronic acid PFBBA and tetramethylboronic acid ester (TMB); thus obtaining an electrode material binder with high ionic conductivity and high voltage resistance.

[0015] Furthermore, the electrode material binder and high-voltage resistant additive are used in a mass ratio of 10:(0.5-1.5).

[0016] Furthermore, the lithium salt is at least one selected from lithium hexafluorophosphate (LiFP6), lithium tetrafluoroborate (LiBF4), lithium bis(oxalate-borate) (LiBOB), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalate-borate) (LiODFB), and lithium bis(fluorosulfonyl)imide (LiFSI).

[0017] Furthermore, the mass concentration of the sodium carboxymethyl cellulose solution is 1.2%.

[0018] Furthermore, when preparing the polyethylene oxide aqueous solution, the stirring time is 24 hours.

[0019] The application of the above-mentioned binder with high ionic conductivity and high voltage resistance in the preparation of positive electrode.

[0020] Furthermore, the electrode material binder, active material, and conductive agent are mixed and slurried. During the slurry preparation process, the high-voltage resistant additive is added. The high-voltage resistant additive is one or two of pentafluorophenylboronic acid (PFBBA) and tetramethylboronic acid ester (TMB). The amount of high-voltage resistant additive added accounts for 0.5-1.5% of the total mass of the electrode material binder, active material, and conductive agent. After stirring evenly, it is coated on an aluminum foil current collector to obtain a positive electrode sheet.

[0021] Furthermore, the mass ratio of the electrode material binder to the active material and the conductive agent is 10:85:5.

[0022] Furthermore, the conductive agent is selected from one or two of Super P and acetylene black; the active material is selected from one of ternary materials (NCM811, NCM622, NCM532), lithium cobalt oxide, lithium nickel oxide, and lithium-rich manganese materials; and the conductive agent is selected from one or more of Super P, acetylene black, carbon nanotubes, or graphene.

[0023] Furthermore, the lithium-rich manganese material is 0.5Li₂MnO₃·0.5LiNi. 0.33 Co 0.33 Mn 0.33 O2.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) This invention introduces polymer chains that can promote lithium-ion migration, significantly improving the ionic conductivity of the binder. In addition, by introducing high-voltage resistant additives, long-term stable cycling under high voltage is achieved. Experimental verification shows that this composite modification method can further improve the electrochemical performance of the cathode material.

[0026] (2) The high ionic conductivity and high voltage resistance of the electrode material binder have excellent high voltage resistance characteristics, and can remain stable under high electric field conditions, making it less prone to breakdown or damage. This stability significantly extends the service life of electronic devices and energy storage systems (such as lithium-ion batteries), and is especially suitable for long-term or high-voltage operation scenarios, improving the reliability and durability of the equipment.

[0027] (3) High ionic conductivity and high voltage resistance electrode material binders possess high ionic conductivity, enabling efficient ion transport and optimizing the contact and electron transport between the electrode material and the electrolyte. They effectively transport ions, such as in lithium-ion batteries, promoting good contact and electron transport between the electrode material and the electrolyte, thereby improving the battery's energy density and charge / discharge efficiency. Novel binders with high ionic conductivity and high voltage resistance not only significantly improve equipment performance and reliability but also provide stronger power support and faster response speeds.

[0028] (4) The modified lithium-rich manganese-based cathode material prepared by the high ionic conductivity and high voltage resistant electrode material binder of the present invention has a discharge specific capacity of up to 295.51 mAh / g and a capacity retention rate of 102.14% after 400 cycles, thus possessing both high capacity and high cycle stability. Attached Figure Description

[0029] Figure 1 The first charge-discharge curve of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 1) at 30°C and 0.1C rate.

[0030] Figure 2 The graph shows the discharge specific capacity degradation of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 1) after 400 cycles at 30°C and 1C.

[0031] Figure 3 This is a graph showing the median voltage decay of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 1) after 400 cycles at 30°C and 1C.

[0032] Figure 4 This is a graph showing the lithium-ion diffusion coefficient of the battery assembled based on modified binder-rich lithium manganese-based cathode material according to the present invention (corresponding to Example 1);

[0033] Figure 5 The first charge-discharge curve of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 2) at 30°C and 0.1C rate;

[0034] Figure 6 This is a discharge specific capacity degradation diagram of the battery assembled based on modified binder lithium-rich manganese-based cathode material according to the present invention (corresponding to Example 2) after 400 cycles at 30°C and 1C.

[0035] Figure 7 This is a graph showing the median voltage decay of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 2) after 400 cycles at 30°C and 1C.

[0036] Figure 8 The first charge-discharge curve of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 3) at 30°C and 0.1C rate;

[0037] Figure 9 This is a discharge specific capacity degradation diagram of the battery assembled based on modified binder lithium-rich manganese-based cathode material according to the present invention (corresponding to Example 3) after 400 cycles at 30°C and 1C.

[0038] Figure 10 This is a graph showing the median voltage decay of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 3) after 400 cycles at 30°C and 1C.

[0039] Figure 11 The first charge-discharge curve of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 4) at 30°C and 0.1C rate;

[0040] Figure 12 This is a discharge specific capacity degradation diagram of the battery assembled based on modified binder lithium-rich manganese-based cathode material according to the present invention (corresponding to Example 4) after 400 cycles at 30°C and 1C.

[0041] Figure 13 This is a TEM image of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 4) after 400 cycles at 30°C and 1C.

[0042] Figure 14 This is a graph showing the median voltage decay of the battery assembled based on the modified binder-rich lithium manganese-based cathode material of the present invention (corresponding to Example 4) after 400 cycles at 30°C and 1C.

[0043] Figure 15 This is a graph showing the lithium-ion diffusion coefficient of the battery assembled based on the modified binder-rich lithium manganese-based cathode material according to the present invention (corresponding to Example 4);

[0044] Figure 16 The first charge-discharge curve of the battery assembled from the product prepared according to the present invention (corresponding to Example 1) at 30°C and 0.1C rate;

[0045] Figure 17 The discharge specific capacity decay diagram of the battery prepared by the present invention (corresponding to Example 1) after assembling the battery under 400 cycles at 30°C and 1C.

[0046] Figure 18 TEM image of the product prepared according to the present invention (corresponding to Example 1) after assembling a battery and cycling it for 400 cycles at 30°C and 1C.

[0047] Figure 19 The median voltage decay graph of the battery prepared by the present invention (corresponding to Example 1) after assembling the battery under 400 cycles at 30°C and 1C conditions.

[0048] Figure 20 The diagram shows the lithium-ion diffusion coefficient of the battery assembled from the product prepared according to the present invention (corresponding to Example 1). Detailed Implementation

[0049] The present invention will be described in further detail below with reference to embodiments and comparative examples, but the implementation of the present invention is not limited thereto.

[0050] Example 1

[0051] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0052] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0053] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 10:1 and stir at room temperature for 12 hours to obtain electrode material binder;

[0054] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry; after stirring evenly, the slurry is coated onto an aluminum foil current collector to obtain a positive electrode sheet, denoted as CPL.

[0055] Using the aforementioned positive electrode, a Li metal sheet as the reference and counter electrode, Celgard 2400 as the separator, and Xinzhoubang 3045I as the electrolyte, the assembly was carried out in an argon-filled glove box with oxygen and water content both less than 0.01 ppm. Its electrochemical performance was tested using a 2025 coin cell on a Xinwei testing system, with a test voltage window of 2.0–4.8 V. The test temperature was 27 ± 1 °C. The first three cycles were activated at a 0.1 C rate (1 C = 200 mAh / g), and from the fourth cycle onwards, a 1 C rate was used for cycling. The performance test results are listed in Table 1.

[0056] Example 2

[0057] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0058] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0059] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 10:1 and stir at room temperature for 12 hours to obtain electrode material binder;

[0060] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry. During the slurry preparation process, pentafluorophenyl boric acid (PFBBA) is added at a ratio of 0.5% of the total mass of the electrode material binder, lithium-rich manganese cathode material, and Super P. After stirring evenly, the mixture is coated onto an aluminum foil current collector to obtain a cathode sheet, denoted as CPL-0.5%PF.

[0061] The battery assembly process is as described in Example 1, and the performance test results are listed in Table 1.

[0062] Example 3

[0063] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0064] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0065] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 10:1 and stir at room temperature for 12 hours to obtain electrode material binder;

[0066] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry. During the slurry preparation process, pentafluorophenyl boric acid (PFBBA) is added at a ratio of 1.0% of the total mass of the electrode material binder, lithium-rich manganese cathode material, and Super P. After stirring evenly, the mixture is coated onto an aluminum foil current collector to obtain a cathode sheet, denoted as CPL-1.0%PF.

[0067] The battery assembly process is as described in Example 1, and the performance test results are listed in Table 1.

[0068] Example 4

[0069] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0070] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0071] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 10:1 and stir at room temperature for 12 hours to obtain electrode material binder;

[0072] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry. During the slurry preparation process, pentafluorophenyl boric acid (PFBBA) is added at a ratio of 1.5% of the total mass of the electrode material binder, lithium-rich manganese cathode material, and Super P. After stirring evenly, the mixture is coated onto an aluminum foil current collector to obtain a cathode sheet, denoted as CPL-1.5%PF.

[0073] The battery assembly process is as described in Example 1, and the performance test results are listed in Table 1.

[0074] Example 5

[0075] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0076] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0077] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 10:1 and stir at room temperature for 12 hours to obtain electrode material binder;

[0078] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry. Tetramethylborate (TMB) is added during the slurry preparation process at a ratio of 0.5% of the total mass of the electrode material binder, lithium-rich manganese cathode material, and Super P. After stirring evenly, the mixture is coated onto an aluminum foil current collector to obtain a cathode sheet, denoted as CPL-0.5%TMB.

[0079] The battery assembly process is as described in Example 1, and the performance test results are listed in Table 1.

[0080] Example 6

[0081] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0082] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0083] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 10:1 and stir at room temperature for 12 hours to obtain electrode material binder;

[0084] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry. Tetramethylborate (TMB) is added during the slurry preparation process at a ratio of 1.0% of the total mass of the electrode material binder, lithium-rich manganese cathode material, and Super P. After stirring evenly, the mixture is coated onto an aluminum foil current collector to obtain a cathode sheet, denoted as CPL-1.0%TMB.

[0085] The battery assembly process is as described in Example 1, and the performance test results are listed in Table 1.

[0086] Example 7

[0087] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0088] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0089] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 10:1 and stir at room temperature for 12 hours to obtain electrode material binder;

[0090] (4) The binder prepared in step (3) is combined with the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry. Tetramethylborate (TMB) is added during the slurry preparation process at a ratio of 1.5% of the total mass of the electrode material binder, lithium-rich manganese cathode material, and Super P. After stirring evenly, the mixture is coated onto an aluminum foil current collector to obtain a cathode sheet, denoted as CPL-1.5%TMB.

[0091] The battery assembly process is as described in Example 1, and the performance test results are listed in Table 1.

[0092] Comparative Example 1

[0093] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to obtain a 1.2% sodium carboxymethyl cellulose solution as a binder;

[0094] (2) The sodium carboxymethyl cellulose binder solution prepared in step (1) is mixed with the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry; the product is denoted as CMC. The battery assembly process is as in Example 1, and the performance test results are listed in Table 1.

[0095] Comparative Example 2

[0096] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0097] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%;

[0098] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide aqueous solution and continue stirring at room temperature for 12 hours. The mass ratio of sodium carboxymethyl cellulose aqueous solution to polyethylene oxide aqueous solution is 10:1 (without lithium salt) to obtain electrode material binder.

[0099] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry; the product is denoted as CP. The battery assembly process is as in Example 1, and the performance test results are listed in Table 1.

[0100] Comparative Example 3

[0101] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0102] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0103] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 1:1 and stir at room temperature for 12 hours to obtain electrode material binder;

[0104] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry; after stirring evenly, the slurry is coated onto an aluminum foil current collector to obtain a positive electrode sheet, denoted as CPL11.

[0105] The battery assembly process is as described in Example 1, and the performance test results are listed in Table 1.

[0106] Comparative Example 4

[0107] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0108] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0109] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 1:2 and stir at room temperature for 12 hours to obtain electrode material binder;

[0110] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry; after stirring evenly, the slurry is coated onto an aluminum foil current collector to obtain a positive electrode sheet, denoted as CPL12.

[0111] The battery assembly process is as described in Example 1, and the performance test results are listed in Table 1.

[0112] Comparative Example 5

[0113] (1) Dissolve sodium carboxymethyl cellulose in deionized water and stir at room temperature for 24 hours to prepare an aqueous solution of sodium carboxymethyl cellulose with a mass concentration of 1.2%;

[0114] (2) Dissolve polyethylene oxide in deionized water and stir at room temperature for 24 hours to prepare a polyethylene oxide aqueous solution with a mass concentration of 1.2%. Add lithium salt LiBOB at a mass ratio of polyethylene oxide to lithium salt of 12:1 to obtain a polyethylene oxide-lithium salt mixture.

[0115] (3) Mix sodium carboxymethyl cellulose aqueous solution with polyethylene oxide-lithium salt mixture at a mass ratio of 1:3 and stir at room temperature for 12 hours to obtain electrode material binder;

[0116] (4) The electrode material binder prepared in step (3) is bonded to the lithium-rich manganese cathode material 0.5Li2MnO3·0.5LiNi 0.33 Co 0.33 Mn 0.33 O2 and Super P are mixed in a mass ratio of 10:85:5 to form a slurry; after stirring evenly, the slurry is coated onto an aluminum foil current collector to obtain a positive electrode sheet, denoted as CPL13.

[0117] The battery assembly process is as described in Example 1, and the performance test results are listed in Table 1.

[0118] Table 1

[0119]

[0120] Comparing Examples 1-4 with Comparative Example 1, it can be seen that introducing a PEO polymer matrix with high ionic conductivity and introducing pentafluorophenylboronic acid (PFBBA) with high voltage resistance can better improve the electrochemical performance of lithium-rich manganese layered oxides; as the content of PFBBA increases, the electrochemical performance is further improved.

[0121] Comparing Examples 1-4 with Comparative Example 2, it can be seen that by introducing a PEO polymer matrix with high ionic conductivity and introducing lithium salt, the ionic conductivity can be improved more effectively, and the electrochemical performance is further enhanced.

[0122] Comparing Examples 1-4 and Comparative Examples 3-5, it can be seen that introducing too much high ionic conductivity PEO polymer matrix destroys the stability of the binder itself, thereby reducing the electrochemical performance of lithium-rich manganese layered oxide.

[0123] Comparative examples 5-7 show that introducing a PEO polymer matrix with high ionic conductivity and introducing tetramethylborate (TMB) with high voltage resistance can also better improve the electrochemical performance of lithium-rich manganese layered oxides; as the content of tetramethylborate (TMB) increases, the electrochemical performance is further improved.

[0124] Comparing Example 1 and Comparative Example 1, it can be seen that the introduction of a PEO polymer matrix with high ionic conductivity effectively improves the electrochemical performance of lithium-rich manganese layered oxides. Figure 13 and Figure 18 The TEM images of the products prepared in Example 4 and Comparative Example 1 after 400 cycles show that after introducing a binder with high ionic conductivity and high voltage resistance, the lithium-rich manganese surface has a uniform CEI film. In contrast, the lithium-rich manganese surface with sodium carboxymethyl cellulose as a binder forms an uneven CEI film.

Claims

1. A method for preparing an adhesive with high ionic conductivity and high voltage resistance, characterized in that, Includes the following steps: Step 1: Prepare a polyethylene oxide-lithium salt mixture Polyoxyethylene was dissolved in deionized water and stirred at room temperature for 24 hours to prepare a polyoxyethylene solution. Lithium salt was added at a mass ratio of 12:1 to polyoxyethylene to lithium salt to obtain a polyoxyethylene-lithium salt mixture. Step 2: Preparation of electrode material binder A sodium carboxymethyl cellulose aqueous solution and a polyethylene oxide-lithium salt mixture were mixed at a mass ratio of 10:1 and stirred at room temperature for 12 hours to obtain an electrode material binder. Step 3: Preparation of a binder for electrode materials with high ionic conductivity and high voltage resistance The electrode material binder and the high-voltage resistant additive are mixed at a mass ratio of 10:(0.5-1.5), wherein the high-voltage resistant additive is one or two of pentafluorophenylboronic acid and tetramethylboronic acid ester; thus, a high ionic conductivity and high voltage resistant electrode material binder is obtained.

2. The method for preparing an adhesive with high ionic conductivity and high voltage resistance according to claim 1, characterized in that, The lithium salt is at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalate)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalate)borate, and lithium bis(fluorosulfonyl)imide.

3. The method for preparing an adhesive with high ionic conductivity and high voltage resistance according to claim 1, characterized in that, The mass concentration of the sodium carboxymethyl cellulose aqueous solution is 1.2%.

4. The method for preparing an adhesive with high ionic conductivity and high voltage resistance according to claim 1, characterized in that, When preparing the polyethylene oxide aqueous solution, the stirring time is 24 hours.

5. The application of a binder with high ionic conductivity and high voltage resistance prepared by the preparation method as described in claim 1 in the preparation of a positive electrode.

6. The application of a binder with high ionic conductivity and high voltage resistance in the preparation of a positive electrode, characterized in that, Electrode material binder, active material, and conductive agent are mixed and slurried. During the slurry preparation process, the high-voltage resistant additive is added. The high-voltage resistant additive is one or two of pentafluorophenylboronic acid and tetramethylboronic acid ester. The amount of high-voltage resistant additive added accounts for 0.5-1.5% of the total mass of electrode material binder, active material, and conductive agent. The mass ratio of electrode material binder to high-voltage resistant additive is 10:(0.5-1.5). After stirring evenly, the mixture is coated onto an aluminum foil current collector to obtain a positive electrode sheet. The electrode material binder is prepared as follows: Step 1: Prepare a polyethylene oxide-lithium salt mixture Polyoxyethylene was dissolved in deionized water and stirred at room temperature for 24 hours to prepare a polyoxyethylene solution. Lithium salt was added at a mass ratio of 12:1 to polyoxyethylene to lithium salt to obtain a polyoxyethylene-lithium salt mixture. Step 2: Preparation of electrode material binder An aqueous solution of sodium carboxymethyl cellulose and a mixture of polyethylene oxide and lithium salt were mixed at a mass ratio of 10:1 and stirred at room temperature for 12 hours to obtain an electrode material binder.

7. The application of the binder with high ionic conductivity and high voltage resistance according to claim 6 in the preparation of the positive electrode, characterized in that, The mass ratio of the electrode material binder to the active material and the conductive agent is 10:85:

5.

8. The application of the binder with high ionic conductivity and high voltage resistance according to claim 6 in the preparation of the positive electrode, characterized in that, The active material is one of NCM811 / NCM622 / NCM532 ternary materials, lithium cobalt oxide, lithium nickel oxide, and lithium-rich manganese materials; the conductive agent is one or more of Super P, acetylene black, carbon nanotubes, or graphene.

9. The application of the binder with high ionic conductivity and high voltage resistance according to claim 8 in the preparation of the positive electrode, characterized in that, The lithium-rich manganese material is 0.5Li₂MnO₃·0.5LiNi. 0.33 Co 0.33 Mn 0.33 O2.

Images