A kind of all-solid-state lithium ion battery structure and its preparation method

Abstract

The application discloses a full-solid-state lithium ion battery structure and a preparation method thereof, and belongs to the technical field of full-solid-state lithium ion batteries. 14 The Al@Na2Li2Ti6O 14 composite negative electrode material is obtained by mixing a lithium source, a sodium source, an aluminum source, a titanium source and oxalic acid and then calcining the mixture; the Na2Li2Ti6O 14 composite negative electrode material, carbon black and a binder with DMF to form negative electrode slurry, coating the negative electrode slurry on the surface of a current collector, drying and cutting to obtain an electrode sheet; and the battery structure is in the order of a negative electrode shell, a lithium sheet, the PEO / LAGP composite solid electrolyte film, the electrode sheet, a stainless steel gasket, a spring sheet and a positive electrode shell. The novel full-solid-state lithium ion battery structure has high charge-discharge specific capacity and stable cycle performance.

Description

Technical Field

[0001] This invention belongs to the field of all-solid-state lithium-ion battery technology, specifically relating to an all-solid-state lithium-ion battery structure and its preparation method. Background Technology

[0002] In recent years, the shortage of fossil energy resources has become increasingly prominent, leading to a continuous increase in market demand for environmentally friendly, high-energy-density energy storage devices. Lithium-ion batteries, with their outstanding energy advantages, have experienced rapid development. Currently, commercially available lithium-ion batteries generally use organic liquid electrolytes. While these electrolytes have good wettability with the electrodes, they have inherent defects such as flammability and leakage. During battery charge-discharge cycles, problems such as leakage, gas expansion, and lithium dendrite growth can easily cause internal short circuits, releasing large amounts of heat in a short time, potentially leading to battery fires or even explosions, posing significant safety hazards and hindering the further promotion and application of lithium-ion batteries. In contrast, all-solid-state batteries constructed using solid-state electrolytes can fundamentally improve battery safety and represent a highly promising energy storage device technology.

[0003] Among various solid-state electrolyte systems, polyethylene oxide (PEO)-based polymer electrolytes have attracted much attention due to their good safety and low interfacial impedance. However, pure PEO electrolytes still suffer from problems such as low ionic conductivity and poor interfacial stability with lithium metal anodes. Introducing inorganic fillers, such as Li, can address these issues. 1.5 Al 0.5 Ge 1.5 (PO4)3 (LAGP) can effectively improve the above-mentioned shortcomings. At the same time, matching it with a negative electrode material with excellent stability and electrochemical performance can further enhance the overall electrochemical performance of all-solid-state batteries.

[0004] Li4Ti5O 12 Lithium-ion oxide (LTO) is a commonly used anode material for lithium-ion batteries. It possesses a unique crystal structure transformation mechanism, resulting in minimal volume change during charging and discharging, thus improving safety and ion storage capacity. Furthermore, the thin SEI film formed on the electrode surface during battery operation is relatively low, which is beneficial for lithium-ion insertion and extraction. However, LTO itself has drawbacks, including low energy density and low electronic conductivity due to empty 3d orbitals, which can lead to performance degradation. Moreover, compared to liquid electrolyte systems, the performance disadvantages of this type of anode material are further amplified in all-solid-state battery systems.

[0005] Therefore, there is an urgent need to develop anode materials with excellent cycle stability and electrochemical performance, and to adapt them to PEO / LAGP composite solid electrolytes to construct a high-performance new all-solid-state lithium-ion battery system. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention aims to provide an all-solid-state lithium-ion battery structure and its preparation method, using Na2Li2Ti6O 14 Composite anode materials are used to prepare anode sheets, and combined with PTO / LAGP composite solid electrolytes, to assemble novel all-solid-state lithium-ion battery structures; Na2Li2Ti6O 14 Composite anode material with Na2Li2Ti6O 14 As a matrix, perform Al 3 + Doping and carbon coating were applied. Na₂Li₂Ti₆O₅ was used. 14 As a derivative of titanate, it has advantages such as lower Li concentration, lower material cost, and a low voltage plateau (1.25V), thereby improving energy density; at the same time, it utilizes Al 3+ Doping with PEO and coating with biochar reduces the contact resistance between the electrolyte and electrode materials, improving the cycling stability and conductivity of the material. In PEO / LAGP composite solid electrolytes, LAGP effectively reduces the crystallinity of PEO, improves the conductive interface between the two phases, and promotes the conductivity of Li. + The transmission.

[0007] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a method for preparing an all-solid-state lithium-ion battery structure, comprising the following steps: Preparation of Na2Li2Ti6O 14 Composite anode material: Lithium source, sodium source, aluminum source, titanium source, and oxalic acid are first mechanically mixed, and then subjected to segmented calcination to obtain Al. 3+ Na₂Li₂Ti₆O 14 Powder, hereinafter referred to as Al@Na2Li2Ti6O 14 Then Al@Na2Li2Ti6O 14 After thorough mechanical mixing with a carbon source, drying, and grinding, Na₂Li₂Ti₆O was obtained. 14 Composite anode materials; Preparation of PEO / LAGP composite solid electrolyte: Under an inert atmosphere, a viscous liquid obtained by mixing and stirring PEO, lithium salt, LAGP and acetonitrile was obtained by solution casting to obtain a PEO / LAGP composite solid electrolyte membrane with uniform thickness. Preparation of electrode sheet: Na2Li2Ti6O 14 The composite negative electrode material is mixed with carbon black and binder, DMF solvent is added, and the mixture is stirred until a uniform and viscous negative electrode slurry is obtained. The negative electrode slurry is coated on the surface of the current collector, vacuum dried, and then cut to obtain electrode sheets. Battery structure assembly: Using the electrode sheet as the working electrode and the lithium sheet as the counter electrode, the battery is assembled and sealed in an argon-filled glove box in the following order: negative electrode shell, lithium sheet, PEO / LAGP composite solid electrolyte membrane, electrode sheet, stainless steel gasket, spring sheet and positive electrode shell, to obtain an all-solid-state lithium-ion battery structure.

[0008] Furthermore, Na2Li2Ti6O was prepared. 14 The specific steps for creating composite anode materials are as follows: (1) The lithium source, sodium source, aluminum source, titanium source and oxalic acid were subjected to a high-energy wet ball milling to obtain a precursor. The precursor was dried and then ground to obtain a white powder. (2) The white powder was calcined in two stages at increasingly higher temperatures to obtain Al@Na2Li2Ti6O 14 ; (3) Al@Na2Li2Ti6O 14 The carbon source was subjected to a second high-energy wet ball milling process, followed by drying and grinding to obtain carbon-coated Al@Na2Li2Ti6O. 14 gray powder, namely Na2Li2Ti6O 14 Composite anode material.

[0009] Furthermore, Na2Li2Ti6O was prepared. 14 In step (1) of the composite anode material, the molar ratio of lithium source, sodium source, aluminum source, titanium source and oxalic acid is (0.92-0.96):1:(0.03-0.07):2.97:1; the lithium source is CH3COOLi·2H2O, the sodium source is CH3COONa, the titanium source is TiO2, and the aluminum source is Al(NO3)3·9H2O. In a single high-energy wet ball milling process, the solvent is ethanol, the milling speed is ≥600 rpm, and the time is 10h-16h; the drying temperature is 80℃-100℃, the drying time is 6h-10h, and the grinding time is 15min-30min.

[0010] Furthermore, Na2Li2Ti6O was prepared. 14 In step (2) of the composite negative electrode material, the first stage of calcination is carried out at a temperature of 400℃-480℃ for 4h-6h; the second stage of calcination is carried out at a temperature of 800℃-900℃ for 10h-12h.

[0011] Furthermore, Na2Li2Ti6O was prepared. 14 In step (3) of the composite anode material, Al@Na2Li2Ti6O 14 The mass ratio of the carbon source to the carbon source is 100:(3-7), and the carbon source is biochar; In the secondary high-energy wet ball milling, the solvent is ethanol, the ball milling speed is ≥600 rpm, and the time is 10h-16h; the drying temperature is 80℃-100℃, the drying time is 6h-10h, and the grinding time is 15min-30min.

[0012] Preferably, the biochar is obtained by calcining dried lotus pods at 500°C for 3 hours in a vacuum drying oven.

[0013] Furthermore, the specific steps for preparing the PEO / LAGP composite solid electrolyte are as follows: (1) In an argon glove box, PEO, lithium salt and LAGP are mixed and acetonitrile is added as solvent. The mixture is stirred in two stages from high to low speed under heating conditions to obtain a uniform, particle-free, viscous mixed liquid. (2) Pour the mixed liquid into a polytetrafluoroethylene mold and let it stand in an argon glove box to air dry naturally to obtain a PEO / LAGP composite solid electrolyte membrane with uniform thickness.

[0014] Furthermore, in step (1) of preparing the PEO / LAGP composite solid electrolyte, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and the mass ratio of PEO, LiTFSI to LAGP is 0.768:0.28:0.2096; During the two-stage stirring process, the heating temperature is 60℃, the stirring speed of the first stage is 600rpm-650rpm, and the time is 12h-16h; the stirring speed of the second stage is 200rpm, and the time is 4h-6h.

[0015] Furthermore, in step (2) of preparing the PEO / LAGP composite solid electrolyte, the standing time is 12h-16h; the thickness of the PEO / LAGP composite solid electrolyte membrane is 0.064mm-0.072mm.

[0016] Furthermore, in the preparation of the electrode sheet, Na2Li2Ti6O 14 The mass ratio of the composite negative electrode material, carbon black, and binder is 6:3:1.

[0017] Secondly, the present invention provides an all-solid-state lithium-ion battery structure, which is prepared by the above-mentioned method for preparing an all-solid-state lithium-ion battery structure; the all-solid-state lithium-ion battery structure is tested for charge-discharge cycles at a rate of 0.5C, and the initial charge specific capacity is ≥214.4mAh / g, and the charge specific capacity after 400 cycles is ≥172.92mAh / g.

[0018] Advantages and effects of the present invention: 1. This invention uses a solid-state method to prepare Na₂Li₂Ti₆O₅. 14The composite anode material exhibits uniform, irregularly shaped spherical nanoparticles. The porous biomass carbon nanoparticles loaded on the material surface effectively inhibit the aggregation of active particles while significantly increasing the overall specific surface area of ​​the composite material. The porous carbon framework accelerates lithium-ion conduction and interfacial material exchange, achieving full adhesion and contact between the anode sheet and the PEO / LAGP solid electrolyte, thus improving the ion transport dynamics of the solid system from a structural perspective.

[0019] 2. The biochar of this invention is produced in Na2Li2Ti6O 14 The composite anode material has a rich carbon network on its particle surface, which is conducive to the formation of Na2Li2Ti6O 14 The matrix provides a continuous conductive shell, compensating for its poor intrinsic electronic conductivity and significantly improving the overall electronic conductivity of the material. Furthermore, Al embedded in the crystal structure... 3+ This can broaden the lithium storage sites inside the crystal, increase the upper limit of lithium ion capacity of the material, and promote the development of Na2Li2Ti6O 14 The composite negative electrode material is uniformly and densely dispersed, maintaining the stability of the electrode structure and high conductivity.

[0020] 3. This invention is the first to use Na2Li2Ti6O 14 A modified negative electrode was matched with a PEO / LAGP composite solid electrolyte to construct an all-solid-state lithium-ion battery structure, achieving synergistic optimization of the electrode-solid electrolyte two-phase interface. The porous structure of biochar effectively alleviates the contact stress at the solid-solid interface, while widening the lithium-ion transport channels and significantly reducing the interface impedance of the solid-state battery core, solving the key pain point of blocked ion conduction at the interface of traditional solid-state batteries.

[0021] 4. The present invention Na2Li2Ti6O 14 Composite anode materials possess considerable reversible capacity with a wide potential window, while also exhibiting excellent rate performance and stable cycle life. They can effectively meet the practical requirements of various applications of solid-state lithium-ion batteries and have high practical value.

[0022] 5. The novel all-solid-state lithium-ion battery structure constructed in this invention has high charge-discharge specific capacity and stable cycle performance. Attached Figure Description

[0023] Figure 1 Na2Li2Ti6O was prepared as described in Example 1. 14 Scanning electron microscope (SEM) images of the composite anode material, where (a) is an SEM image with a scale bar of 2 μm and (b) is an SEM image with a scale bar of 500 nm. Figure 2 The rate performance diagram of the all-solid-state lithium-ion battery structure in Example 1 is shown in the potential range of 0.0V-3.0V. Figure 3The graph shows the cycle performance of the all-solid-state lithium-ion battery structure in Example 1 at a rate of 0.5C. Figure 4 The rate performance diagram of the all-solid-state lithium-ion battery structure in Example 2 is shown in the potential range of 0.0V-3.0V. Figure 5 The graph shows the cycle performance of the all-solid-state lithium-ion battery structure in Example 2 at a rate of 0.5C. Figure 6 The rate performance diagram of the all-solid-state lithium-ion battery structure in Example 3 is shown in the potential range of 0.0V-3.0V. Figure 7 The graph shows the cycle performance of the all-solid-state lithium-ion battery structure in Example 3 at a rate of 0.5C. Detailed Implementation

[0024] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0025] A method for preparing an all-solid-state lithium-ion battery structure includes the following steps: Preparation of Na2Li2Ti6O 14 Composite anode materials: (1) CH3COOLi·2H2O, CH3COONa, Al(NO3)3·9H2O, TiO2 and oxalic acid are mixed in a molar ratio of (0.92-0.96):1:(0.03-0.07):2.97:1, ethanol is added, and the mixture is subjected to a high-energy wet ball milling at a speed of more than 600 rpm for 10-16 hours to obtain a precursor. The precursor is dried at 80℃-100℃ for 6-10 hours and then ground for 15-30 minutes to obtain a white powder. (2) The white powder was first calcined at 400℃-480℃ for 4h-6h, and then calcined at 800℃-900℃ for 10h-12h to obtain Al@Na2Li2Ti6O 14 ; (3) Dried lotus pods were placed in a vacuum drying oven and calcined at 500°C for 3 hours to obtain biochar. Al@Na2Li2Ti6O 14 The mixture was mixed with biochar at a mass ratio of 100:(3-7), ethanol was added, and the mixture was subjected to a second high-energy wet ball milling at a speed of 600 rpm or higher for 10 h-16 h. Then it was dried at 80℃-100℃ for 6 h-10 h, and then ground for 15 min-30 min to obtain carbon-coated Al@Na2Li2Ti6O. 14 gray powder, namely Na2Li2Ti6O 14 Composite anode material.

[0026] Preparation of PEO / LAGP composite solid electrolyte: (1) In an argon glove box, PEO, lithium salt LiTFSI and LAGP were mixed in a mass ratio of 0.768:0.28:0.2096, and an appropriate amount of solvent acetonitrile was added. The mixture was stirred at 600 rpm-650 rpm for 12-16 hours at 60°C, and then stirred at 200 rpm for 4-6 hours to obtain a uniform, particle-free, viscous mixed liquid. (2) Pour the mixed liquid into a polytetrafluoroethylene mold and let it stand in an argon glove box for 12-16 hours to air dry naturally to obtain a PEO / LAGP composite solid electrolyte membrane with a uniform thickness of 0.064mm-0.072mm.

[0027] Electrode preparation: First, PEO and LiTFSI were added to DMF solvent and stirred at 600 rpm for 12 h at 60 °C. Then, the resulting solution was allowed to stand at room temperature for 30 min to obtain a uniform binder solution. Then, Na₂Li₂Ti₆O₂ was added... 14 The composite negative electrode material is mixed with carbon black and binder at a mass ratio of 6:3:1, and an appropriate amount of DMF solvent is added. The mixture is stirred at 35°C for more than 10 hours until a uniform and viscous negative electrode slurry is obtained. The negative electrode slurry is coated on the surface of the current collector and vacuum dried at 120°C for 12 hours. Finally, the dried electrode is cut into circular electrode sheets.

[0028] Battery assembly structure: Using the electrode sheet as the working electrode and the lithium sheet as the counter electrode, the battery is assembled and sealed in the following order: negative electrode shell, lithium sheet, PEO / LAGP composite solid electrolyte membrane, electrode sheet, stainless steel gasket, spring sheet and positive electrode shell, to obtain an all-solid-state lithium-ion battery structure.

[0029] An all-solid-state lithium-ion battery structure was prepared using the above-mentioned method for preparing all-solid-state lithium-ion battery structures. The all-solid-state lithium-ion battery structure was tested for charge-discharge cycles at a rate of 0.5C. The initial specific capacity was 214.4 mAh / g, and the specific capacity after 400 cycles was ≥172.92 mAh / g.

[0030] Example 1 A method for preparing an all-solid-state lithium-ion battery structure includes the following steps: Preparation of Na2Li2Ti6O 14 Composite anode materials: (1) Take 0.49g of CH3COOLi·2H2O, 0.41g of CH3COONa, 0.06g of Al(NO3)3·9H2O, 1.185g of TiO2 and 0.45g of oxalic acid and mix them in ethanol. Then, perform a high-energy wet ball milling at 600rpm for 12h to obtain the precursor. After drying the precursor in an 80℃ drying oven for 6h, grind it thoroughly in a mortar for 15min to obtain a white powder. (2) The white powder was first calcined in a muffle furnace at 400°C for 4 hours, and then calcined at 800°C for 10 hours in air atmosphere to obtain Al@Na2Li2Ti6O 14 ; (3) Dried lotus pods were placed in a vacuum drying oven and calcined at 500°C for 3 hours to obtain biochar. Al@Na2Li2Ti6O 14 The mixture was dissolved in ethanol at a mass ratio of 100:5 with biochar, and subjected to a second high-energy wet ball milling at 600 rpm for 12 h. It was then dried in an oven at 80 °C for 6 h, and finally ground thoroughly in a mortar for 15 min to obtain carbon-coated Al@Na2Li2Ti6O. 14 gray powder, namely Na2Li2Ti6O 14 Composite anode material. Observations using SEM show, for example... Figure 1 As shown, Na₂Li₂Ti₆O prepared by solid-state method 14 The composite anode material exhibits a uniformly distributed, irregularly spherical morphology of nanoparticles with a particle size of 200 nm-500 nm and an average particle size of 400 nm, and only a small amount of agglomeration; simultaneously, Na₂Li₂Ti₆O₂ is visible. 14 The rough surface of the composite anode material, covered with tiny carbon nanoparticles, demonstrates that biochar has successfully adhered to the atomic surface, and its rich carbon network is Na₂Li₂Ti₆O. 14 Composite anode materials provide a continuous conductive shell, which in turn significantly improves the overall electronic conductivity.

[0031] Preparation of PEO / LAGP composite solid electrolyte: (1) In an argon glove box, take 0.768g of PEO, 0.28g of LiTFSI and 0.2096g of LAGP and add them to a glass bottle. Then add 15mL of solvent acetonitrile and stir at 600rpm for 12h at 60℃. Then stir at 200rpm for 5h in two stages to obtain a uniform, particle-free, viscous mixed liquid. (2) Pour the mixed liquid into a polytetrafluoroethylene mold and let it stand in an argon glove box for 12 hours to air dry naturally, so as to obtain a PEO / LAGP composite solid electrolyte membrane with a uniform thickness of 0.071 mm.

[0032] Electrode preparation: First, 11.4 g of DMF solvent was added to a glass bottle, followed by 0.44 g of PEO and 0.16 g of LiTFSI. The bottle was then placed on a stirrer and stirred at 60°C and 600 rpm for 12 hours. After stirring, the resulting solution was allowed to stand at room temperature for 30 minutes to obtain a homogeneous binder solution. Then, Na2Li2Ti6O... 14 The composite negative electrode material is mixed with carbon black and binder at a mass ratio of 6:3:1, and an appropriate amount of DMF solvent is added. The mixture is stirred at 35°C for more than 10 hours until a uniform and viscous negative electrode slurry is obtained. The negative electrode slurry is coated on the surface of the current collector and vacuum dried at 120°C for 12 hours. The dried electrode is cut into circular electrode sheets for subsequent battery assembly.

[0033] Battery structure assembly: Using the electrode sheet as the working electrode and the lithium sheet as the counter electrode, the battery is assembled and sealed in an argon-filled glove box in the following order: negative electrode shell, lithium sheet, PEO / LAGP composite solid electrolyte membrane, electrode sheet, stainless steel gasket, spring sheet and positive electrode shell, to obtain an all-solid-state lithium-ion battery structure.

[0034] A fully solid-state lithium-ion battery structure was described, and a CR2032 coin-type solid-state lithium-ion battery was assembled using the preparation method of the fully solid-state lithium-ion battery structure in Example 1 of this paper. Charge-discharge cycle tests were conducted at 60°C at different rates within a potential range of 0.0V-3.0V, achieving a 1C value of 1600 mAh / g. Figure 2 As shown, at charging rates of 0.2C, 0.3C, 0.5C, 1C, and 2C, the specific charging capacities are 284.81 mAh / g, 225.98 mAh / g, 172.93 mAh / g, 115.97 mAh / g, and 79.17 mAh / g, respectively. When the charging rate returns to 0.2C, the specific charging capacity remains at 242.59 mAh / g, only slightly lower than the initial value, confirming that the battery structure has good reversibility. Charge-discharge cycle tests were conducted at a 0.5C rate, as shown... Figure 3 As shown, due to incomplete reaction in the first cycle, the initial charging specific capacity reached 270.94 mAh / g starting from the second cycle. After 400 cycles, the charging specific capacity remained at 178.25 mAh / g, demonstrating good cycle stability and high coulombic efficiency.

[0035] Example 2 A method for preparing an all-solid-state lithium-ion battery structure includes the following steps: Preparation of Na2Li2Ti6O 14 Composite anode materials: (1) Take 0.48g of CH3COOLi·2H2O, 0.41g of CH3COONa, 0.09g of Al(NO3)3·9H2O, 1.185g of TiO2 and 0.45g of oxalic acid and mix them in ethanol. Then, perform a high-energy wet ball milling at 600rpm for 12h to obtain the precursor. After drying the precursor in an 80℃ drying oven for 6h, grind it thoroughly in a mortar for 15min to obtain a white powder. (2) The white powder was first calcined in a muffle furnace at 400°C for 4 hours, and then calcined at 800°C for 10 hours in air atmosphere to obtain Al@Na2Li2Ti6O 14 ; (3) Dried lotus pods were placed in a vacuum drying oven and calcined at 500°C for 3 hours to obtain biochar. Al@Na2Li2Ti6O 14 The mixture was dissolved in ethanol at a mass ratio of 100:5 with biochar, and subjected to a second high-energy wet ball milling at 600 rpm for 12 h. It was then dried in an oven at 80 °C for 6 h, and finally ground thoroughly in a mortar for 15 min to obtain carbon-coated Al@Na2Li2Ti6O. 14 gray powder, namely Na2Li2Ti6O 14 Composite anode material.

[0036] Preparation of PEO / LAGP composite solid electrolyte: (1) In an argon glove box, take 0.768g of PEO, 0.28g of LiTFSI and 0.2096g of LAGP and add them to a glass bottle. Then add 15mL of solvent acetonitrile and stir at 600rpm for 12h at 60℃. Then stir at 200rpm for 5h in two stages to obtain a uniform, particle-free, viscous mixed liquid. (2) Pour the mixed liquid into a polytetrafluoroethylene mold and let it stand in an argon glove box for 12 hours to air dry naturally, so as to obtain a PEO / LAGP composite solid electrolyte membrane with a uniform thickness of 0.071 mm.

[0037] Electrode preparation: First, 11.4 g of DMF solvent was added to a glass bottle, followed by 0.44 g of PEO and 0.16 g of LiTFSI. The bottle was then placed on a stirrer and stirred at 60°C and 600 rpm for 12 hours. After stirring, the resulting solution was allowed to stand at room temperature for 30 minutes to obtain a homogeneous binder solution. Then, Na2Li2Ti6O... 14The composite negative electrode material is mixed with carbon black and binder at a mass ratio of 6:3:1, and an appropriate amount of DMF solvent is added. The mixture is stirred at 35°C for more than 10 hours until a uniform and viscous negative electrode slurry is obtained. The negative electrode slurry is coated on the surface of the current collector and vacuum dried at 120°C for 12 hours. The dried electrode is cut into circular electrode sheets for subsequent battery assembly.

[0038] Battery structure assembly: Using the electrode sheet as the working electrode and the lithium sheet as the counter electrode, the battery is assembled and sealed in an argon-filled glove box in the following order: negative electrode shell, lithium sheet, PEO / LAGP composite solid electrolyte membrane, electrode sheet, stainless steel gasket, spring sheet and positive electrode shell, to obtain an all-solid-state lithium-ion battery structure.

[0039] A fully solid-state lithium-ion battery structure was constructed using the preparation method of the fully solid-state lithium-ion battery structure in Example 2 of this paper, and assembled into a CR2032 coin-type solid-state lithium-ion battery. Charge-discharge cycle tests were conducted at 60°C at different rates within a potential range of 0.0V-3.0V, achieving a 1C value of 1600 mAh / g. Figure 4 As shown, at charging rates of 0.2C, 0.3C, 0.5C, 1C, and 2C, the specific charging capacities are 301.75 mAh / g, 259.98 mAh / g, 218.4 mAh / g, 168.5 mAh / g, and 121.99 mAh / g, respectively. When the charging rate returns to 0.2C, the specific charging capacity remains at 261.57 mAh / g, only slightly lower than the initial value, confirming that the battery structure has good reversibility. Charge-discharge cycle tests were conducted at a 0.5C rate, as shown... Figure 5 As shown, due to incomplete reaction in the first cycle, the initial charging specific capacity reached 236.48 mAh / g starting from the second cycle. After 400 cycles, the charging specific capacity remained at 215.98 mAh / g, demonstrating good cycle stability and high coulombic efficiency.

[0040] Example 3 A method for preparing an all-solid-state lithium-ion battery structure includes the following steps: Preparation of Na2Li2Ti6O 14 Composite anode materials: (1) Take 0.47g of CH3COOLi·2H2O, 0.41g of CH3COONa, 0.13g of Al(NO3)3·9H2O, 1.185g of TiO2 and 0.45g of oxalic acid and mix them in ethanol. Then, perform a high-energy wet ball milling at 600rpm for 12h to obtain the precursor. After drying the precursor in an 80℃ drying oven for 6h, grind it thoroughly in a mortar for 15min to obtain a white powder. (2) The white powder was first calcined in a muffle furnace at 400°C for 4 hours, and then calcined at 800°C for 10 hours in air atmosphere to obtain Al@Na2Li2Ti6O 14 ; (3) Dried lotus pods were placed in a vacuum drying oven and calcined at 500°C for 3 hours to obtain biochar. Al@Na2Li2Ti6O 14 The mixture was dissolved in ethanol at a mass ratio of 100:5 with biochar, and subjected to a second high-energy wet ball milling at 600 rpm for 12 h. It was then dried in an oven at 80 °C for 6 h, and finally ground thoroughly in a mortar for 15 min to obtain carbon-coated Al@Na2Li2Ti6O. 14 gray powder, namely Na2Li2Ti6O 14 Composite anode material.

[0041] Preparation of PEO / LAGP composite solid electrolyte: (1) In an argon glove box, take 0.768g of PEO, 0.28g of LiTFSI and 0.2096g of LAGP and add them to a glass bottle. Then add 15mL of solvent acetonitrile and stir at 600rpm for 12h at 60℃. Then stir at 200rpm for 5h in two stages to obtain a uniform, particle-free, viscous mixed liquid. (2) Pour the mixed liquid into a polytetrafluoroethylene mold and let it stand in an argon glove box for 12 hours to air dry naturally, so as to obtain a PEO / LAGP composite solid electrolyte membrane with a uniform thickness of 0.071 mm.

[0042] Electrode preparation: First, 11.4 g of DMF solvent was added to a glass bottle, followed by 0.44 g of PEO and 0.16 g of LiTFSI. The bottle was then placed on a stirrer and stirred at 60°C and 600 rpm for 12 hours. After stirring, the resulting solution was allowed to stand at room temperature for 30 minutes to obtain a homogeneous binder solution. Then, Na2Li2Ti6O... 14 The composite negative electrode material is mixed with carbon black and binder at a mass ratio of 6:3:1, and an appropriate amount of DMF solvent is added. The mixture is stirred at 35°C for more than 10 hours until a uniform and viscous negative electrode slurry is obtained. The negative electrode slurry is coated on the surface of the current collector and vacuum dried at 120°C for 12 hours. The dried electrode is cut into circular electrode sheets for subsequent battery assembly.

[0043] Battery structure assembly: Using the electrode sheet as the working electrode and the lithium sheet as the counter electrode, the battery is assembled and sealed in an argon-filled glove box in the following order: negative electrode shell, lithium sheet, PEO / LAGP composite solid electrolyte membrane, electrode sheet, stainless steel gasket, spring sheet and positive electrode shell, to obtain an all-solid-state lithium-ion battery structure.

[0044] A fully solid-state lithium-ion battery structure was constructed using the preparation method of the fully solid-state lithium-ion battery structure in Example 3 of this paper, and assembled into a CR2032 coin-type solid-state lithium-ion battery. Charge-discharge cycle tests were conducted at 60°C at different rates within a potential range of 0.0V-3.0V, achieving a 1C value of 1600 mAh / g. Figure 6 As shown, at charging rates of 0.2C, 0.3C, 0.5C, 1C, and 2C, the specific charging capacities are 284.45 mAh / g, 243.12 mAh / g, 205.37 mAh / g, 158.92 mAh / g, and 115.34 mAh / g, respectively. When the charging rate returns to 0.2C, the specific charging capacity remains at 248.83 mAh / g, only slightly lower than the initial value, confirming that the battery structure has good reversibility. Charge-discharge cycle tests were conducted at a 0.5C rate, as shown... Figure 7 As shown, due to incomplete reaction in the first cycle, the initial charging specific capacity reached 232.12 mAh / g starting from the second cycle. After 400 cycles, the charging specific capacity remained at 181.25 mAh / g, demonstrating good cycle stability and high coulombic efficiency.

[0045] Example 4 A method for preparing an all-solid-state lithium-ion battery structure includes the following steps: Preparation of Na2Li2Ti6O 14 Composite anode materials: (1) Take 0.475g of CH3COOLi·2H2O, 0.41g of CH3COONa, 0.075g of Al(NO3)3·9H2O, 1.185g of TiO2 and 0.45g of oxalic acid and mix them in ethanol. Then, perform a high-energy wet ball milling at 700rpm for 10h to obtain the precursor. After drying the precursor in a drying oven at 90℃ for 8h, grind it thoroughly in a mortar for 20min to obtain a white powder. (2) The white powder was first calcined in a muffle furnace at 440°C for 5 hours, and then calcined at 850°C for 11 hours in air atmosphere to obtain Al@Na2Li2Ti6O 14 ; (3) Dried lotus pods were placed in a vacuum drying oven and calcined at 500°C for 3 hours to obtain biochar. Al@Na2Li2Ti6O 14 The mixture was dissolved in ethanol at a mass ratio of 100:3 with biochar, and subjected to a second high-energy wet ball milling at 700 rpm for 10 h. It was then dried in an oven at 90 °C for 8 h, and finally ground thoroughly in a mortar for 20 min to obtain carbon-coated Al@Na2Li2Ti6O. 14 gray powder, namely Na2Li2Ti6O 14 Composite anode material.

[0046] Preparation of PEO / LAGP composite solid electrolyte: (1) In an argon glove box, take 0.768g of PEO, 0.28g of LiTFSI and 0.2096g of LAGP and add them to a glass bottle. Then add 15mL of solvent acetonitrile and stir at 620rpm for 14h at 60℃. Then stir at 200rpm for 4h in two stages to obtain a uniform, particle-free, viscous mixed liquid. (2) Pour the mixed liquid into a polytetrafluoroethylene mold and let it stand in an argon glove box for 14 hours to air dry naturally, so as to obtain a PEO / LAGP composite solid electrolyte membrane with a uniform thickness of 0.064 mm.

[0047] Electrode preparation: First, 11.4 g of DMF solvent was added to a glass bottle, followed by 0.44 g of PEO and 0.16 g of LiTFSI. The bottle was then placed on a stirrer and stirred at 60°C and 600 rpm for 12 hours. After stirring, the resulting solution was allowed to stand at room temperature for 30 minutes to obtain a homogeneous binder solution. Then, Na2Li2Ti6O... 14 The composite negative electrode material is mixed with carbon black and binder at a mass ratio of 6:3:1, and an appropriate amount of DMF solvent is added. The mixture is stirred at 35°C for more than 10 hours until a uniform and viscous negative electrode slurry is obtained. The negative electrode slurry is coated on the surface of the current collector and vacuum dried at 120°C for 12 hours. The dried electrode is cut into circular electrode sheets for subsequent battery assembly.

[0048] Battery structure assembly: Using the electrode sheet as the working electrode and the lithium sheet as the counter electrode, the battery is assembled and sealed in an argon-filled glove box in the following order: negative electrode shell, lithium sheet, PEO / LAGP composite solid electrolyte membrane, electrode sheet, stainless steel gasket, spring sheet and positive electrode shell, to obtain an all-solid-state lithium-ion battery structure.

[0049] A fully solid-state lithium-ion battery structure was prepared using the method described in Example 4 of this paper, and assembled into a CR2032 coin-type solid-state lithium-ion battery. Charge-discharge cycle tests were conducted at 60°C at different rates within the 0.0V-3.0V potential range. At 1C = 1600 mAh / g, the specific charging capacities at rates of 0.2C, 0.3C, 0.5C, 1C, and 2C were 270 mAh / g, 233.9 mAh / g, 190.44 mAh / g, 127.12 mAh / g, and 86.32 mAh / g, respectively. When the rate returned to 0.2C, the specific charging capacity remained at 244.63 mAh / g, only slightly lower than the initial value, confirming that the battery structure has good reversibility. Charge-discharge cycle tests were conducted at a 0.5C rate. Due to incomplete reaction in the first cycle, the results were recorded starting from the second cycle. The initial charging specific capacity reached 214.4 mAh / g, and after 400 cycles, the charging specific capacity remained at 192.17 mAh / g, demonstrating good cycle stability and high coulombic efficiency.

[0050] Example 5 A method for preparing an all-solid-state lithium-ion battery structure includes the following steps: Preparation of Na2Li2Ti6O 14 Composite anode materials: (1) Take 0.485g of CH3COOLi·2H2O, 0.41g of CH3COONa, 0.115g of Al(NO3)3·9H2O, 1.185g of TiO2 and 0.45g of oxalic acid and mix them in ethanol. Then, perform a high-energy wet ball milling at 800rpm for 16h to obtain the precursor. After drying the precursor in a drying oven at 100℃ for 10h, grind it thoroughly in a mortar for 30min to obtain a white powder. (2) The white powder was first calcined in a muffle furnace at 480°C for 6 hours, and then calcined at 900°C for 12 hours in air atmosphere to obtain Al@Na2Li2Ti6O 14 ; (3) Dried lotus pods were placed in a vacuum drying oven and calcined at 500°C for 3 hours to obtain biochar. Al@Na2Li2Ti6O 14 The mixture was dissolved in ethanol at a mass ratio of 100:7 with biochar, and subjected to a second high-energy wet ball milling at 800 rpm for 16 h. It was then dried in an oven at 100 °C for 10 h, and finally ground thoroughly in a mortar for 30 min to obtain carbon-coated Al@Na2Li2Ti6O. 14 gray powder, namely Na2Li2Ti6O 14 Composite anode material.

[0051] Preparation of PEO / LAGP composite solid electrolyte: (1) In an argon glove box, take 0.768g of PEO, 0.28g of LiTFSI and 0.2096g of LAGP and add them to a glass bottle. Then add 15mL of solvent acetonitrile and stir at 650rpm for 16h at 60℃. Then stir at 200rpm for 6h in two stages to obtain a uniform, particle-free, viscous mixed liquid. (2) Pour the mixed liquid into a polytetrafluoroethylene mold and let it stand in an argon glove box for 16 hours to air dry naturally, so as to obtain a PEO / LAGP composite solid electrolyte membrane with a uniform thickness of 0.072 mm.

[0052] Electrode preparation: First, 11.4 g of DMF solvent was added to a glass bottle, followed by 0.44 g of PEO and 0.16 g of LiTFSI. The bottle was then placed on a stirrer and stirred at 60°C and 600 rpm for 12 hours. After stirring, the resulting solution was allowed to stand at room temperature for 30 minutes to obtain a homogeneous binder solution. Then, Na2Li2Ti6O... 14 The composite negative electrode material is mixed with carbon black and binder at a mass ratio of 6:3:1, and an appropriate amount of DMF solvent is added. The mixture is stirred at 35°C for more than 10 hours until a uniform and viscous negative electrode slurry is obtained. The negative electrode slurry is coated on the surface of the current collector and vacuum dried at 120°C for 12 hours. The dried electrode is cut into circular electrode sheets for subsequent battery assembly.

[0053] Battery structure assembly: Using the electrode sheet as the working electrode and the lithium sheet as the counter electrode, the battery is assembled and sealed in an argon-filled glove box in the following order: negative electrode shell, lithium sheet, PEO / LAGP composite solid electrolyte membrane, electrode sheet, stainless steel gasket, spring sheet and positive electrode shell, to obtain an all-solid-state lithium-ion battery structure.

[0054] A fully solid-state lithium-ion battery structure was prepared using the method described in Example 5 of this paper, and assembled into a CR2032 coin-type solid-state lithium-ion battery. Charge-discharge cycle tests were conducted at 60°C at different rates within the 0.0V-3.0V potential range. At 1C = 1600 mAh / g, the specific charging capacities at rates of 0.2C, 0.3C, 0.5C, 1C, and 2C were 274.72 mAh / g, 209.53 mAh / g, 163.84 mAh / g, 110.48 mAh / g, and 77.49 mAh / g, respectively. When the rate returned to 0.2C, the specific charging capacity remained at 237.14 mAh / g, only slightly lower than the initial value, confirming that the battery structure has good reversibility. Charge-discharge cycle tests were conducted at a 0.5C rate. Due to incomplete reaction in the first cycle, the results were recorded starting from the second cycle. The initial specific capacity reached 216.24 mAh / g, and after 400 cycles, the specific capacity remained at 172.92 mAh / g, demonstrating good cycle stability and high coulombic efficiency.

Claims

1. A method for preparing an all-solid-state lithium-ion battery structure, characterized in that, Includes the following steps: Preparation of Na2Li2Ti6O 14 Composite anode material: Lithium source, sodium source, aluminum source, titanium source, and oxalic acid are first mechanically mixed, and then subjected to segmented calcination to obtain Al. 3+ Na₂Li₂Ti₆O 14 Powder, hereinafter referred to as Al@Na2Li2Ti6O 14 Then Al@Na2Li2Ti6O 14 After thorough mechanical mixing with a carbon source, drying, and grinding, Na₂Li₂Ti₆O was obtained. 14 Composite anode materials; Preparation of PEO / LAGP composite solid electrolyte: Under an inert atmosphere, a viscous liquid obtained by mixing and stirring PEO, lithium salt, LAGP and acetonitrile was obtained by solution casting to obtain a PEO / LAGP composite solid electrolyte membrane with uniform thickness. Preparation of electrode sheet: Na2Li2Ti6O 14 The composite negative electrode material is mixed with carbon black and binder, DMF solvent is added, and the mixture is stirred until a uniform and viscous negative electrode slurry is obtained. The negative electrode slurry is coated on the surface of the current collector, vacuum dried, and then cut to obtain electrode sheets. Battery structure assembly: Using the electrode sheet as the working electrode and the lithium sheet as the counter electrode, the battery is assembled and sealed in an argon-filled glove box in the following order: negative electrode shell, lithium sheet, PEO / LAGP composite solid electrolyte membrane, electrode sheet, stainless steel gasket, spring sheet and positive electrode shell, to obtain an all-solid-state lithium-ion battery structure.

2. The method for preparing an all-solid-state lithium-ion battery structure according to claim 1, characterized in that, Preparation of Na2Li2Ti6O 14 The specific steps for creating composite anode materials are as follows: (1) The lithium source, sodium source, aluminum source, titanium source and oxalic acid were subjected to a high-energy wet ball milling to obtain a precursor. The precursor was dried and then ground to obtain a white powder. (2) The white powder was calcined in two stages at increasingly higher temperatures to obtain Al@Na2Li2Ti6O 14 ; (3) Al@Na2Li2Ti6O 14 The carbon source was subjected to a second high-energy wet ball milling process, followed by drying and grinding to obtain carbon-coated Al@Na2Li2Ti6O. 14 gray powder, namely Na2Li2Ti6O 14 Composite anode material.

3. The method for preparing an all-solid-state lithium-ion battery structure according to claim 2, characterized in that, Preparation of Na2Li2Ti6O 14 In step (1) of the composite anode material, the molar ratio of lithium source, sodium source, aluminum source, titanium source and oxalic acid is (0.92-0.96):1:(0.03-0.07):2.97:1; the lithium source is CH3COOLi·2H2O, the sodium source is CH3COONa, the titanium source is TiO2, and the aluminum source is Al(NO3)3·9H2O; In a single high-energy wet ball milling process, the solvent is ethanol, the milling speed is ≥600 rpm, and the time is 10h-16h; the drying temperature is 80℃-100℃, the drying time is 6h-10h, and the grinding time is 15min-30min.

4. The method for preparing an all-solid-state lithium-ion battery structure according to claim 2, characterized in that, Preparation of Na2Li2Ti6O 14 In step (2) of the composite negative electrode material, the first stage of calcination is carried out at a temperature of 400℃-480℃ for 4h-6h; the second stage of calcination is carried out at a temperature of 800℃-900℃ for 10h-12h.

5. The method for preparing an all-solid-state lithium-ion battery structure according to claim 2, characterized in that, Preparation of Na2Li2Ti6O 14 In step (3) of the composite anode material, Al@Na2Li2Ti6O 14 The mass ratio of the carbon source to the carbon source is 100:(3-7), and the carbon source is biochar; In the secondary high-energy wet ball milling, the solvent is ethanol, the ball milling speed is ≥600 rpm, and the time is 10h-16h; the drying temperature is 80℃-100℃, the drying time is 6h-10h, and the grinding time is 15min-30min.

6. The method for preparing an all-solid-state lithium-ion battery structure according to claim 1, characterized in that, The specific steps for preparing the PEO / LAGP composite solid electrolyte are as follows: (1) In an argon glove box, PEO, lithium salt and LAGP are mixed and acetonitrile is added as solvent. The mixture is stirred in two stages from high to low speed under heating conditions to obtain a uniform, particle-free, viscous mixed liquid. (2) Pour the mixed liquid into a polytetrafluoroethylene mold and let it stand in an argon glove box to air dry naturally to obtain a PEO / LAGP composite solid electrolyte membrane with uniform thickness.

7. The method for preparing an all-solid-state lithium-ion battery structure according to claim 6, characterized in that, In step (1) of preparing the PEO / LAGP composite solid electrolyte, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and the mass ratio of PEO, LiTFSI and LAGP is 0.768:0.28:0.2096; During the two-stage stirring process, the heating temperature is 60℃, the stirring speed of the first stage is 600rpm-650rpm, and the time is 12h-16h; the stirring speed of the second stage is 200rpm, and the time is 4h-6h.

8. The method for preparing an all-solid-state lithium-ion battery structure according to claim 6, characterized in that, In step (2) of preparing the PEO / LAGP composite solid electrolyte, the standing time is 12h-16h; the thickness of the PEO / LAGP composite solid electrolyte membrane is 0.064mm-0.072mm.

9. The method for preparing an all-solid-state lithium-ion battery structure according to claim 1, characterized in that, In the preparation of the electrode sheet, Na2Li2Ti6O 14 The mass ratio of the composite negative electrode material, carbon black, and binder is 6:3:

1.

10. An all-solid-state lithium-ion battery structure, prepared by the method for preparing the all-solid-state lithium-ion battery structure according to any one of claims 1-9, characterized in that, The all-solid-state lithium-ion battery structure was tested for charge-discharge cycles at a rate of 0.5C. The initial charge specific capacity was ≥214.4mAh / g, and the charge specific capacity after 400 cycles was ≥172.92mAh / g.

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