Solid electrolyte with modification layer and preparation method thereof

Abstract

The invention relates to a solid electrolyte with a modification layer and a preparation method thereof. The solid electrolyte with the modification layer comprises a solid electrolyte and the modification layer coated on the solid electrolyte, and the solid electrolyte is connected with the modification layer through a hydrogen bond; the modification layer comprises a carbon substrate subjected to acid treatment and silver nanoparticles modified on the carbon substrate.

Description

Technical Field

[0001] The invention relates to a solid electrolyte with a modified layer and a preparation method thereof. Background Art

[0002] Lithium batteries are widely commercialized in portable electronic devices and electric vehicle applications. Lithium batteries have high energy density and safety. However, the performance of lithium batteries is usually limited by the high interfacial resistance between the anode and the solid electrolyte. The contact between lithium metal and the solid electrolyte is often insufficient, resulting in high interfacial resistance and the formation of lithium dendrites at the interface. Summary of the invention

[0003] The present application discloses a solid electrolyte with a modified layer for a lithium battery and a preparation method thereof.

[0004] One aspect of the present invention discloses a solid electrolyte with a modified layer, comprising: a solid electrolyte and a modified layer coated on the solid electrolyte, wherein the solid electrolyte and the modified layer are connected by hydrogen bonds, and the modified layer comprises an acid-treated carbon matrix and silver nanoparticles modified on the carbon matrix.

[0005] Another aspect of the present invention discloses a lithium metal battery, comprising: a positive electrode, an electrolyte on the positive electrode, and a lithium negative electrode on the electrolyte, wherein the electrolyte is a solid electrolyte with a modified layer, comprising: a solid electrolyte and a modified layer coated on the solid electrolyte, the solid electrolyte and the modified layer are connected by hydrogen bonds, and the modified layer comprises a modified acid-treated carbon matrix and silver nanoparticles modified on the carbon matrix.

[0006] In an aspect that may be combined with any other aspect or embodiment, the modifying layer has a thickness in the range of 0.2-10 μm.

[0007] In an aspect that may be combined with any other aspect or embodiment, the silver nanoparticles have a particle size in the range of 2-80 nm.

[0008] In an aspect that may be combined with any other aspect or embodiment, a weight ratio of silver nanoparticles in the modification layer is in a range of 30% to 50%.

[0009] In an aspect that may be combined with any other aspect or embodiment, the carbon matrix comprises: carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene oxide (GO), three-dimensional (3D) carbon, or a combination thereof.

[0010] In an aspect that may be combined with any other aspect or embodiment, the carbon matrix is ​​a carbon nanotube having an aspect ratio in the range of 100-300.

[0011] In an aspect that may be combined with any other aspect or embodiment, the porosity of the finishing layer is in the range of 20% to 60%.

[0012] In an aspect that may be combined with any other aspect or embodiment, the solid electrolyte comprises: Li 7 La 3 Zr 2 O 12 (LLZO), tantalum-doped garnet electrolyte (LLZTO), Li 10 G 2 S 12 , Li 1.5 Al 0.5 Ge 1.5 (PO4) 3 , Li 1.4 Al 0.4 Ti 1.6 (PO4) 3 , Li 0.55 La 0.35 TiO 3 or a combination thereof.

[0013] Another aspect of the present invention discloses a method for preparing a solid electrolyte with a modified layer, comprising: acid-treating a carbon substrate; modifying silver nanoparticles on the acid-treated carbon substrate to obtain the acid-treated carbon substrate and silver nanoparticles modified thereon (Ag NPs@CNTs), and then mixing the Ag NPs@CNTs in a suspension and coating the suspension on the solid electrolyte; drying and annealing the solid electrolyte to obtain the solid electrolyte with the modified layer.

[0014] In an aspect that may be combined with any other aspect or embodiment, the weight percentage of Ag NPs@CNTs in the suspension is in the range of 2% to 6%.

[0015] In an aspect that may be combined with any other aspect or embodiment, further comprising sensitizing the acid-treated carbon substrate with a tin ion solution after the acid-treated carbon substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present disclosure will become more easily understood through the detailed description in conjunction with the following drawings, wherein:

[0017] Figure 1 Schematic diagram and characterization diagram of the preparation of silver nanoparticles modified on an acid-treated carbon substrate and modified thereon in some embodiments. Figure 1 A is a schematic diagram of the preparation of Ag NPs@CNTs powder; Figure 1 Medium B to Figure 1 D in the middle is a field emission scanning electron microscope (FESEM) image; Figure 1 Middle E to Figure 1G in the middle is a scanning electron microscope (TEM) image; Figure 1 Medium B and Figure 1 The E in the middle represents carbon nanotubes (CNTs). Figure 1 Middle C and Figure 1 F in the middle represents CNTs after acid treatment. Figure 1 Medium D and Figure 1 G represents the AgNPs@CNTs powder ( Figure 1 Middle scale ruler: BD is 500 nm, EG is 100 nm).

[0018] Figure 2 Figure 2 is a material characterization diagram of the acid-treated carbon substrate and the silver nanoparticles modified thereon during the preparation process in some embodiments. Figure 2 A is the X-ray diffraction pattern (XRD), Figure 2 B is the thermogravimetric analysis of CNTs, acid-treated CNTs, and Ag NPs@CNTs powders. au represents arbitrary units, i.e., the relative values ​​after normalization.

[0019] Figure 3 Schematic diagram and characterization diagram of the preparation process of a solid electrolyte with a modified layer in some embodiments. Figure 3 A in the figure is a schematic diagram of the preparation process of a solid electrolyte with a modified layer. Figure 3 Figure 3B, Figure 3C, Figure 3E, and Figure 3F are field emission scanning electron microscope images (FESEM, scale bars: 5 μm for B and E, 400 nm for C and F). Figure 3 Medium B and Figure 3 Middle C corresponds Figure 3 LLZTO-AGC BA in A, i.e., FESEM image of Ag NPs@CNTs suspension coated on the surface of solid electrolyte LLZTO after drying; Figure 3 The middle E corresponds to the 3rd middle F. Figure 3 A in the middle is the FESEM image of LLZTO-AGC, i.e. the solid electrolyte with modified layer after annealing; Figure 3 Medium D and Figure 3 G in the figure are the corresponding element mapping spectra of LLZTO-AGC BA and LLZTO-AGC, respectively.

[0020] Figure 4 Interface features of the LLZTO-AGC BA and LLZTO-AGC in some embodiments are shown.

[0021] Figure 5 Graphs representing materials in some embodiments. Figure 5 A in the figure is the FTIR spectra of AGC, LLZTO and their mixed powders; Figure 5B in the figure is the XRD patterns of LLZTO, LLZTO-AGC BA and LLZTO-AGC.

[0022] Figure 6 Cross-sectional FESEM images of Li / LLZTO and Li / LLZTO-AGC in some embodiments (scale bar: 5 μm).

[0023] Figure 7 Electrochemical evaluation of lithium symmetric cells in some embodiments. Figure 7 Middle A and Figure 7 B is the impedance curve. Figure 7 C in the figure is the CCD measurement under step current density. Figure 7 D in the figure is the cycling performance of Li / LLZTO / Li and Li / AGC-LLZTO-AGC / Li symmetric batteries at different current densities at 25°C.

[0024] Figure 8 Electrochemical performance of quasi-solid-state batteries in some embodiments. Figure 8 A in the figure is a schematic diagram of the NCM83TMS / LLZTO-AGC / Li full battery. Figure 8 B in the figure is the rate performance curve. Figure 8 The charge and discharge curves under C of 0.1, 0.2, 0.5, 1, 2 and 0.1C, Figure 8 D in the middle is the low-load NCM83 TMS / LLZTO-AGC / Li full battery impedance curve, Figure 8 E in the middle is the low-load full battery cycle performance curve. Figure 8 F in the middle is the charge and discharge curve of the full battery at low load at 0.2C. Figure 8 Middle G is the impedance curve of NCM83TMS / LLZTO-AGC / Li full battery with high load. Figure 8 Middle H is the high load full battery cycle performance curve, Figure 8 I is the full cell with high load at 0.5 mA cm -2 The charge and discharge curves below. DETAILED DESCRIPTION

[0025] Some exemplary embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. Whenever possible, the same reference numerals will be used in all drawings to refer to the same or similar meanings. The components in the drawings are not necessarily drawn to scale, but the focus is on the principles of the exemplary embodiments given. It should be understood that the present application is not limited to the details or methods set forth in the specification or shown in the drawings. It should also be understood that the terms used in the present disclosure are for descriptive purposes only and should not be considered restrictive.

[0026] In addition, any examples set forth in this application are illustrative, not restrictive, and only set forth some of the many possible embodiments of the claimed invention. It is obvious to those skilled in the art that some non-essential other suitable modifications and adjustments made to various conditions and parameters commonly encountered in the art are within the scope of protection of this disclosure.

[0027] Due to the rigidity of the solid electrolyte, its wettability with lithium is poor, and the contact is poor, resulting in large interface resistance, uneven lithium ion flux during the cycle, and the concentrated lithium ion flow further causes dendrites to penetrate rapidly along the grain boundaries, ultimately resulting in a short life of the garnet-based solid-state battery. The present invention proposes to modify the surface of the solid electrolyte to solve the above problems.

[0028] In an aspect that may be combined with any other aspect or embodiment, the solid electrolyte may include Li 7 La 3 Zr 2 O 12 (LLZO), tantalum-doped garnet electrolyte (LLZTO), Li 10 G 2 S 12 , Li 1.5 Al 0.5 Ge 1.5 (PO4) 3 , Li 1.4 Al 0.4 Ti 1.6 (PO4) 3 , Li 0.55 La 0.35 TiO 3 at least one or a combination thereof.

[0029] In some examples, the negative electrode may include lithium metal (Li). In some examples, the battery may include at least one negative electrode protection measure, such as an electrolyte additive (e.g., LiNO 3 , lanthanum nitrate, copper acetate, P 2 S 5 etc.), artificial interface layer (such as Li 3 N,(CH 3 ) 3 SiCl, Al 2 O 3 , LiAl, etc.), composite metals (e.g., Li 7 B 6 , Li-rGO (reduced graphene oxide), layered Li-rGO, etc., or a combination thereof.

[0030] In an aspect that can be combined with any other aspect or embodiment, the positive electrode may include at least one of lithium-based electrodes. The lithium-based electrodes include lithium cobalt oxide (LCO), lithium manganese spinel (LMO), lithium nickel cobalt aluminate (NCA), lithium nickel manganese cobalt oxide (NCM) (LiNi d Co e Mn 1-d-e O 2 , where 0 < d < 1, 0 < e < 1, for example LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), etc.), lithium iron phosphate (LiFePO 4 )(LFP), lithium cobalt phosphate (LCP), lithium titanate, lithium niobium tungstate, lithium nickel manganate, and lithium titanium sulfide (LiTiS 2 ) and at least one of them.

[0031] The description and formation method of the solid electrolyte are described in the following examples.

[0032] Example 1 - Preparation of Ag NPs@CNTs powder First, acid-treat carbon nanotube (CNT) powder: Prepare a mixed acid of 25 ml of concentrated nitric acid and 75 ml of concentrated sulfuric acid. Then, add 20 ml of a 10 wt.% CNTs dispersion (purchased from XFNANO Company) to the mixed acid, heat it in a water bath at 70 °C and stir for 1 hour, where the aspect ratio of the CNTs is in the range of 100 to 300. Centrifuge at 5000 rpm for 3 minutes to obtain acid-treated CNTs, wash them four times with deionized water, and vacuum filter with a large amount of deionized water until the filtrate is neutral. Obtain acid-treated CNT powder by freeze-drying for 24 hours.

[0033] Secondly, sensitize CNTs with a tin ion (Sn 2+ ) solution: Dissolve 0.3 - 0.12 g of SnCl 2 ·2H 2 O in 50 ml of 0.1 molar per liter of HCl, then add 0.25 g of acid-treated CNT powder to the solution and sonicate for 45 minutes. Centrifuge at 5000 rpm for 3 minutes and wash 3 times with deionized water to obtain Sn 2+ -sensitized CNTs. Disperse the prepared Sn 2+ -sensitized CNTs in 10 ml of deionized water.

[0034] Again, silver ammonia solution: add 0.5 g of silver nitrate to 40 ml of deionized water, then add 0.2 ml of 0.1 mol / L sodium hydroxide under stirring, and then add 2.5 ml of ammonia water (containing 6.6% by weight of ammonia) dropwise into the mixture to form a silver ammonia solution.

[0035] Finally, Ag NPs@CNTs powder was obtained: the pre-prepared Sn 2+ The sensitized CNTs dispersion was gradually added to the newly prepared silver ammonia solution and stirred continuously at room temperature for 1-5 hours. Next, the resulting Ag NPs@CNTs were collected by centrifugation at 5000 rpm for 3 minutes. Then, the mixture was washed repeatedly with deionized water for 3 times to ensure that excess ions and unreacted substances were completely removed. Finally, after 24 hours of freeze-drying, the Ag NPs@CNTs powder was obtained. The particle size of the silver nanoparticles in the Ag NPs@CNTs powder obtained by FESEM analysis was in the range of 2-20 nm, and thermogravimetric analysis showed that the weight ratio of the silver nanoparticles was in the range of 30% to 50%.

[0036] Example 2-Preparation of LLZTO solid electrolyte

[0037] The conventional solid phase method was used to synthesize Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (LLZTO) and sintered it into ceramic particles. 2 O(AR), La 2 O 3 (99.99%), ZrO 2 (AR) and Ta 2 O 5 (99.99%) were mixed in a stoichiometric ratio and 10 wt.% excess LiOH·H was added 2 O was ball milled. The dried La2O3 powder was heated at 900°C for 12 hours. The powder mixture was calcined in an alumina crucible at 950°C for 6 hours to obtain cubic phase LLZTO powder. The LLZTO powder was ball milled at 250rpm for 24 hours to obtain refined powder. The prepared LLZTO powder was then pressed into sheets in a platinum crucible in air and calcined at 1250°C for 30 minutes. The LLZTO was polished and stored in an argon-filled glove box. The final LLZTO sheet had a thickness of approximately 1.0 mm and a diameter of approximately 13.5 mm.

[0038] Example 3 - Preparation of Ag NPs@CNTs modified LLZTO (LLZTO-AGC) .

[0039] Ag NPs@CNTs modified LLZTO (LLZTO-AGC) was prepared by slurry coating technology. First, Ag NPs@CNTs powder and PVDF as a binder were stirred in N-methylpyrrolidone (NMP) at a weight ratio of 95:5 for 12 hours. The solid content ranged from 2% to 6% by weight. Then, 15-50μL of the slurry was dropped onto the polished LLZTO surface and vacuum dried at 70°C for 12 hours to further evaporate the solvent, thereby obtaining Ag NPs@CNTs modified LLZTO (LLZTO-AGC BA) before annealing. Annealing at 600°C in Ar for 2 hours to remove PVDF and residual NMP to obtain LLZTO-AGC. FESEM analysis showed that the thickness of the modified layer was in the range of 0.2-10μm, and Image J software measurement showed that the porosity of the modified layer was in the range of 20% to 60%.

[0040] Example 4 - Assembling a symmetrical lithium battery

[0041] To prepare lithium / LLZTO / lithium or lithium / AGC-LLZTO-AGC / symmetric lithium batteries, the lithium anode was applied to both sides of the polished LLZTO or AGC-LLZTO-AGC by a melting method at 400°C in an argon-filled glove box for 3 minutes. All batteries were assembled in CR2025 coin cells. In aspects that can be combined with any other aspect or embodiment, heating is performed at a temperature in the range of 250°C to 400°C, or 275°C to 375°C, or 300°C to 350°C (e.g., 340°C), or 250°C to 300°C, or 350°C to 400°C, or any value or range disclosed therein. In aspects that can be combined with any other aspect or embodiment, the time is 1 second to 20 minutes, or 30 seconds to 15 minutes, or 1 minute to 10 minutes, or 3 minutes to 10 minutes, or 5 minutes to 10 minutes, or any value or range disclosed therein.

[0042] Example 5 - Assembly of low-load quasi-solid-state full battery

[0043] To prepare the low-loading NCM83 TMS / LLZTO-AGC / Li full cell, the lithium anode was coated on the LLZTO-AGC surface by a melt method at 400 °C in an argon-filled glove box for 3 min. 0.83 Co 0.12 Mn 0.05 O 2 The mass loading of (NCM83) is 3–4 mg cm -2The full cells were wetted with 15 μL of a 1.2 mol lithium bis(fluorosulfonyl)imide (LiFSI) solution in tetramethylene sulfone (TMS) at the cathode / LLZTO-AGC interface. All cells were assembled in CR2025 coin cells.

[0044] Example 6-Assembly of high-load quasi-solid-state full battery

[0045] To prepare high-loading NCM83 TMS / LLZTO-AGC / Li full cells, the lithium anode was coated on the LLZTO-AGC surface by a melt method at 400 °C in an argon-filled glove box for 3 min. 0.83 Co 0.12 Mn 0.05 O 2 The mass loading of (NCM83) was 17–17.5 mg cm -2 The full cell was wetted using 20 μL of a solution of 1.2 mol lithium bis(fluorosulfonyl)imide (LiFSI) in tetramethylene sulfone (TMS) at the cathode / LLZTO-AGC interface. All cells were assembled in CR2025 coin cells.

[0046] Example 7 - Characterization Studies

[0047] Morphology and phase analysis

[0048] FESEM images were obtained by field emission scanning electron microscopy (FESEM, Hitachi S-3400N and Magellan 400), and the surface elemental composition was detected by coupled energy dispersive X-ray spectroscopy (EDS). TEM images were obtained by transmission electron microscopy (TEM, JEOL JEM-2100F). X-ray diffraction (XRD) was performed using a Rigaku Ultima IV to determine the phase of the samples. Thermogravimetric analysis (NETZSCH, STA 409PC) was performed to study the weight ratio of Ag nanoparticles in AgNPs@CNTs.

[0049] Electrochemical performance

[0050] Electrochemical impedance spectroscopy (EIS) was measured by AC impedance analysis (Autolab, model PGSTAT302 N) in the frequency range of 0.1 Hz–1 MHz. All Li symmetric cells and full cells were tested on a Neware battery test system (NEWARECT-4008, Shenzhen, China). The Li symmetric cells were tested at an initial current density of 0.1 mA cm -2 The rate cycle test was carried out under the condition of 0.1 mA·cm-2 The critical current density of LLZTO and LLZTO-AGC was determined by the increment of . The charge and discharge time was set to 30 min. For the full cell, the charge current density was 0.14 mA cm in the voltage range of 2.8–4.3 V. -2 or 0.5 mA cm -2 The battery was tested by constant current cycling.

[0051] Example 8 - Sample preparation

[0052] Sample 1 :

[0053] Ag NPs@CNTs powder and PVDF were mixed in N-methylpyrrolidone (NMP) at a weight ratio of 95:5 and stirred for 12 hours. The solid content was 4.5wt.%. 15 μL of the slurry was dropped onto the polished LLZTO surface and vacuum dried at 70°C for 12 hours to further evaporate the solvent. LLZTO-AGC was obtained by removing PVDF and residual NMP by annealing at 600°C in argon for 2 hours. In order to make Li / AGC-LLZTO-AGC / Li symmetric cells, the lithium anode was applied to both sides of the AGC-LLZTO-AGC by a melting method at 400°C in an argon-filled glove box. All batteries were assembled in CR2025 coin cells.

[0054] Sample 2 :

[0055] Ag NPs@CNTs powder and PVDF were mixed in N-methylpyrrolidone (NMP) at a weight ratio of 95:5 and stirred for 12 hours. The solid content was 4.5wt.%. 15 μL of the slurry was dropped onto the polished LLZTO surface and vacuum dried at 70 °C for 12 hours to further evaporate the solvent. LLZTO-AGC was obtained by removing PVDF and residual NMP by annealing at 600 °C in argon for 2 hours. In order to make a low-load NCM83 TMS / LLZTO-AGC / Li full cell, the lithium anode was coated on the LLZTO-AGC surface by a melting method at 400 °C in an argon-filled glove box. LiNi 0.83 Co 0.12 Mn 0.05 O 2 The mass loading of (NCM83) is 3-4 mg cm -2 The full cell was wetted with 15 μL of 1.2 mol LiFSI in TMS at the cathode / LLZTO-AGC interface. All cells were assembled in CR2025 coin cells.

[0056] Sample 3 :

[0057] Ag NPs@CNTs powder and PVDF were mixed in N-methylpyrrolidone (NMP) at a weight ratio of 95:5 and stirred for 12 hours. The solid content was 4.5wt.%. 15 μL of the slurry was dropped onto the polished LLZTO surface and vacuum dried at 70 °C for 12 hours to further evaporate the solvent. LLZTO-AGC was obtained by removing PVDF and residual NMP by annealing at 600 °C in argon for 2 hours. In order to make a high-load NCM83 TMS / LLZTO-AGC / Li full cell, the lithium anode was coated on the LLZTO-AGC surface by a melting method at 400 °C in an argon-filled glove box. LiNi 0.83 Co 0.12 Mn 0.05 O 2 The mass loading of (NCM83) was 17–17.5 mg cm -2 The full cell was wetted with 20 μL of 1.2 mol LiFSI in TMS at the cathode / LLZTO-AGC interface. All cells were assembled in CR2025 coin cells.

[0058] Comparative sample 1 :

[0059] The prepared LLZTO was only polished. In an argon-filled glove box, the unmodified, only polished LLZTO was coated with lithium anode on both sides by a melt method at 400°C for 3 minutes. Symmetric lithium cells were assembled in 2025-type button cells.

[0060] Figure 1 The preparation process and morphological characteristics of the material are shown. Figure 1 As shown in Figure A, silver nanopowder (Ag NPs@CNTs) modified on an acid-treated carbon matrix was synthesized by a two-step method. The carbon nanotubes were treated with acid to increase the surface active sites, and then the silver nanoparticles were deposited on the surface of the acid-treated carbon nanotubes through a redox reaction to form silver nanopowder on the acid-treated carbon matrix (silver nanoparticles@carbon nanotubes or Ag NPs@CNTs). The chemical changes that occurred in this process can be expressed by the following chemical equation: Sn 2+ +2Ag + =Sn 4+ +2Ag). The average diameter of the carbon nanotubes is about 50nm and the length is about 10μm. They were purchased from XFNANO. The surface of the acid-treated carbon nanotubes is rough, with many small protrusions and defects. These defects serve as active sites, which are conducive to the deposition of silver. Figure 1 Field emission scanning electron microscope (FESEM) images and Figure 1Scanning electron microscope (TEM) image of E in the middle. After the silver nanoparticles are deposited, the original structure of the nanotubes is maintained. The size of the silver nanoparticles on the surface is about 5nm and is evenly distributed. Figure 1 FESEM images of D and Figure 1 TEM image of G

[0061] Figure 2 The X-ray diffraction (XRD) pattern of the material is shown, Figure 2 As shown in Figure A, the phase structure of silver nanoparticles@carbon nanotubes (AgNPs@CNTs) powder is metallic silver phase (PDF#87-0717), in addition to the phase structure of carbon nanotubes (PDF#75-1621). Thermogravimetric analysis results show that Figure 2 As shown in B, the weight ratio of silver nanoparticles in Ag NPs@CNTs is about 40wt.%.

[0062] Figure 3 The preparation process and morphological characteristics of LLZTO-AGC BA and LLZTO-AGC are shown. Silver nanoparticles@carbon nanotubes modified LLZTO (LLZTO-AGC) ( Figure 3 15 μL of silver nanoparticles@carbon nanotubes (AGC) slurry was dropped onto the polished LLZTO surface and dried to form silver nanoparticles@carbon nanotubes modified LLZTO (LLZTO-AGC BA, Figure 3 After annealing, a 3D network layer is formed on the surface of LLZTO-AGC, which has a porous structure and good uniformity over a large area ( Figure 3 During the annealing process, the silver nanoparticles in the AGC layer that promote molten Li wetting grow from about 5 nm to about 50 nm ( Figure 3 Middle C and Figure 3 Middle F).

[0063] Figure 4 The interface characteristics of LLZTO-AGC are shown. The modified layer (AGC) has a vertical thickness of 4.3 microns and is in good contact with LLZTO, making the surface of LLZTO smooth by filling surface pores and voids. It is speculated that the acid-treated carbon nanotubes combine with LLZTO, promoting the wettability of the carbon nanotube matrix to LLZTO, forming an ideal bonding interface.

[0064] Figure 5 The material characterization is shown. AGC and LLZTO in Fourier transform infrared spectroscopy (FTIR) spectra ( Figure 5 The hydroxyl peaks in A) are 3420 cm -1 and 3450cm -1, moved to 3420 cm in the spectrum of LLZTO and AGC mixed powder -1 , indicating that hydrogen bonds were formed between hydroxyl groups. Due to the formation of hydrogen bonds between acid-treated carbon nanotubes and LLZTO, the wettability of carbon nanotube matrix to LLZTO was promoted, forming an ideal bonding interface. XRD pattern ( Figure 5 (C) shows that LLZTO maintains a cubic phase structure in LLZTO-AGC. The peak at 26.2° corresponds to carbon nanotubes, and the peaks at 38.1°, 44.3°, 64.5°, and 77.4° correspond to silver.

[0065] Figure 6 The interfacial behaviors between Li / LLZTO and Li / LLZTO-AGC were compared. The Li / LLZTO interface was constructed by the molten lithium method. A piece of lithium foil was attached to LLZTO and heated to 400°C for 3 minutes. For the original LLZTO (polished only), the FESEM image shows that the lithium shrinks and forms wrinkles after cooling ( Figure 6 Middle A, left), there are clear gaps (micrometer scale) between the interfaces. For LLZTO-AGC, the lithium diffuses after cooling and appears smooth ( Figure 6 B, right), no gaps or defects were observed at the interface, demonstrating that Li is in close contact with LLZTO.

[0066] Figure 7 The electrochemical performance of the Li symmetric cell at 25 °C is shown. To evaluate the electrochemical performance of the constructed Li / LLZTO-AGC interface, a Li / AGC-LLZTO-AGC / Li symmetric cell was assembled. As a control, a Li / LLZTO / Li cell was also prepared using the same method. The interface resistance increased from 55 Ωcm 2 (Comparative sample 1, Figure 7 A) drops sharply to 0.25Ωcm 2 (Sample 1, Figure 7 B), indicating that the Li / LLZTO-AGC interface is not only continuous on the LLZTO physical surface, but also electrochemically tight. Figure 7 As shown in C, by 0.1-2 mA cm -2 The range is 0.1 mA cm -2 The step current density test was performed to determine the CCD of the cell. As the current density increased, the voltage response increased steadily without a sudden voltage drop until the current density exceeded 1.8 mA cm -2 , which shows that the CCD of Li / AGC-LLZTO-AGC / Li battery is 1.7 mA cm -2 (Sample 1). Compared with the 0.5 mA cm -2The CCD is significantly improved compared to the original. To demonstrate the interfacial stability, the symmetric cells were cycled for a long time. Figure 7 D shows the current density of 0.5 mA cm -2 , the corresponding electrochemical stripping / plating curves of lithium at a cycle time of 30 min. The Li / AGC-LLZTO-AGC / Li battery was stably cycled for 2155 h with small and stable voltage polarization, indicating that the Li / LLZTO-AGC interface is highly stable. In contrast, the Li / LLZTO / Li battery showed severe polarization.

[0067] Figure 8 The electrochemical performance of the quasi-solid-state full cells (samples 2 and 3) is shown. Figure 8 A in the figure shows the structure of the battery. Figure 8 Medium B and Figure 8 As shown in C, the rate performance of the battery is carried out at rates of 0.1, 0.2, 0.5, 1, 2, and 0.1C, and the discharge capacities are 198, 194, 182, 162, 131, and 202 mAh g, respectively. -1 When discharged at a high rate of 2C, the discharge capacity is 66% of that at 0.1C. The resistance of the low-load NCM83 TMS / LLZTO-AGC / Li full cell is 120Ωcm 2 ( Figure 8 D), the initial discharge capacity is 0.68 mAh cm -2 The battery is 0.14 mA cm -2 After 380 cycles, it can maintain 0.56 mAh cm -2 The discharge capacity and capacity retention rate are 82% ( Figure 8 ZhongE and Figure 8 Middle F). The resistance of the high-load NCM83 TMS / LLZTO-AGC / Li full cell is 150Ωcm 2 ( Figure 8 G), the initial discharge capacity (4th cycle) is 3.33 mAh cm -2 At 0.5 mA cm -2 After 75 cycles, the battery can maintain 2.98 mAh cm -2 The capacity retention rate is 92% ( Figure 8 Medium H and Figure 8 This indicates that the AGC layer with 3D structure and porosity can alleviate the Li / SSE interface damage during cycling and allow large-capacity lithium deposition / stripping, thus matching the high-load cathode and obtaining good cycling performance of quasi-solid-state batteries.

[0068] The advantages of the present invention include: (1) Low interfacial resistance: The modified layer achieves close contact with the solid electrolyte (SSE) and the lithium anode, so that the interface exhibits ideal solid-solid contact characteristics, with a resistance of only 0.25Ω·cm 2 (2) Higher critical current density: The modified layer successfully inhibits the formation of lithium dendrites and guides the lithium plating and stripping process to be more uniform, with a critical current density of up to 1.7 mA cm -2 (3) Higher interface stability: The presence of the modified layer helps alleviate interface problems and significantly prolongs the cycle life of the battery. -2 (4) High-load cathode: The modified layer with three-dimensional (3D) structure and porosity reduces the damage of lithium / solid electrolyte (SSE) interface during the cycle and enables high-capacity lithium plating / stripping. This feature enables the material to match high-load cathode and endow solid-state batteries with excellent cycling performance.

[0069] As used herein, the terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning consistent with the common and recognized usage by those of ordinary skill in the art to which the disclosed subject matter relates. It should be understood by those skilled in the art, and by those reviewing the present invention, that these terms are intended to allow for a description of certain features described and claimed without limiting the scope of such features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that unrealistic or inconsequential modifications or alterations to the described and claimed subject matter are considered to be within the scope of the present invention as described in the appended claims.

[0070] As used herein, the terms "particles" and "powder" have substantially the same meaning and can be used interchangeably without affecting the understanding and implementation of the technical content of the present invention. When describing the present invention, the expressions "particles" or "powder" refer to the same type of solid substances, i.e., solid particles with a size ranging from microns to millimeters. These particles can have various shapes, such as spheres, cubes, cylinders, polyhedrons, etc., or can be a mixture of multiple shapes.

[0071] The specific and preferred values ​​disclosed for components, ingredients, additives, dimensions, conditions, times and the like and their ranges are for illustration only; they do not exclude other defined values ​​or other values ​​within defined ranges. The compositions, articles and methods of the present disclosure may include any value or any combination of values, specific values, more specific values ​​and preferred values ​​described herein, including explicit or implicit intermediate values ​​and ranges.

[0072] For the use of substantially any plural and / or singular terms in the art, those skilled in the art can translate them from plural to singular and / or from singular to plural, depending on the context and / or application. For the sake of clarity, various singular / plural arrangements may be explicitly described herein.

[0073] It is obvious to those skilled in the art that some non-essential improvements and adjustments made according to the above content of the present invention all belong to the protection scope of the present invention. Therefore, the subject matter claimed for protection is not limited unless according to the attached claims and their equivalents.

Claims

1. A solid electrolyte having a modified layer, include: A solid electrolyte and a modified layer coated on the solid electrolyte, wherein the solid electrolyte and the modified layer are connected by hydrogen bonds, and wherein the modified layer comprises an acid-treated carbon matrix and silver nanoparticles modified on the carbon matrix.

2. The solid electrolyte with a modified layer according to claim 1, It is characterized in that The thickness of the modified layer is in the range of 0.2-10 μm.

3. The solid electrolyte with a modified layer according to claim 1, It is characterized in that The particle size of the silver nanoparticles is in the range of 2-80 nm.

4. The solid electrolyte with a modified layer according to claim 1, It is characterized in that The weight ratio of the silver nanoparticles in the modification layer is in the range of 30% to 50%.

5. The solid electrolyte with a modified layer according to claim 1, It is characterized in that The carbon matrix includes: carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene oxide (GO), three-dimensional (3D) carbon or a combination thereof.

6. The solid electrolyte with a modified layer according to claim 1, It is characterized in that The carbon matrix is ​​a carbon nanotube having an aspect ratio in the range of 100 to 300.

7. The solid electrolyte with a modified layer according to claim 1, It is characterized in that The porosity of the modified layer is in the range of 20% to 60%.

8. The solid electrolyte with a modified layer according to claim 1, It is characterized in that The solid electrolyte comprises: Li 7 La 3 Zr 2 O 12 (LLZO), tantalum-doped garnet electrolyte (LLZTO), Li 10 G 2 S 12 , Li 1.5 Al 0.5 Ge 1.5 (PO4) 3 , Li 1.4 Al 0.4 Ti 1.6 (PO4) 3 , Li 0.55 La 0.35 TiO 3 or a combination thereof.

9. A lithium battery, include: A positive electrode, an electrolyte on the positive electrode, and a lithium negative electrode on the electrolyte, wherein the electrolyte is a solid electrolyte with a modified layer, including: a solid electrolyte and a modified layer coated on the solid electrolyte, the solid electrolyte and the modified layer are connected by hydrogen bonds, and characterized in that the modified layer includes an acid-treated carbon matrix and silver nanoparticles modified on the carbon matrix.

10. The lithium metal battery according to claim 9, It is characterized in that The thickness of the modified layer is in the range of 0.2-10 μm.

11. The lithium battery according to claim 9, It is characterized in that The particle size of the silver nanoparticles is in the range of 2-80 nm.

12. The lithium battery according to claim 9, It is characterized in that The weight ratio of the silver nanoparticles in the modification layer is in the range of 30% to 50%.

13. The lithium battery according to claim 9, It is characterized in that The carbon matrix includes: carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene oxide (GO), three-dimensional (3D) carbon or a combination thereof.

14. The lithium battery according to claim 9, It is characterized in that The carbon matrix is ​​a carbon nanotube having an aspect ratio in the range of 100 to 300.

15. The lithium battery according to claim 9, It is characterized in that The porosity of the modified layer is in the range of 20% to 60%.

16. The lithium battery according to claim 9, It is characterized in that The solid electrolyte comprises: Li 7 La 3 Zr 2 O 12 (LLZO), tantalum-doped garnet electrolyte (LLZTO), Li 10 G 2 S 12 , Li 1.5 Al 0.5 Ge 1.5 (PO4) 3 , Li 1.4 Al 0.4 Ti 1.6 (PO4) 3 , Li 0.55 La 0.35 TiO 3 or a combination thereof.

17. A method for preparing a solid electrolyte having a modified layer, It is characterized in that include: Acid-treated carbon substrate; Modifying silver nanoparticles on an acid-treated carbon substrate to obtain silver nanoparticles modified on the acid-treated carbon substrate (Ag NPs@CNTs), and then mixing the Ag NPs@CNTs in a suspension and coating the Ag NPs@CNTs on the solid electrolyte; The solid electrolyte is dried and annealed to obtain a solid electrolyte having a modified layer.

18. The method according to claim 17, It is characterized in that The weight percentage of Ag NPs@CNTs in the suspension ranged from 2% to 6%.

19. The method according to claim 17, It is characterized in that The method further comprises sensitizing the acid-treated carbon substrate with a tin ion solution after the acid-treated carbon substrate.

Images