Carbon-based interface layer and method of preparation and use thereof in a battery

Abstract

The application discloses a carbon-based interface layer, which comprises a lithium-containing layer, and a carbon layer is arranged on the surface of the lithium-containing layer, wherein the carbon layer comprises soft carbon and doped nanoscale lithium lanthanum zirconium oxygen particles, and the doped nanoscale lithium lanthanum zirconium oxygen particles are uniformly dispersed in the soft carbon. The interface layer is particularly suitable for a negative electrode sheet, a 3D ion conductive network is formed in the interface layer, the fast transmission of Li + is promoted, the local current density is effectively reduced, the lithium ion flux is homogenized, and the growth of lithium dendrites is inhibited.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and specifically to a carbon-based interface layer for batteries and its preparation method. Background Technology

[0002] All-solid-state lithium metal batteries, by combining a non-flammable solid electrolyte with a high-energy-density lithium metal anode, have become a current research hotspot, promising to simultaneously address safety issues and improve energy density. Among various solid electrolytes, sulfide solid electrolytes are particularly popular due to their high room-temperature conductivity (10⁻⁶ Ω·cm). -3 S cm -1 The above has garnered widespread attention. Sulfides (reduced at ≈1.6V and oxidized at ≈2.3V) are best known for their high lithium-ion conductivity, attributed to the large size and polarizability of sulfide ions. Sulfides exhibit high room-temperature ionic conductivity up to 25 mS / cm. -1 With low grain boundary resistance and mechanical flexibility, sulfide-based all-solid-state lithium metal batteries can be densified at room temperature through cold pressing and exhibit high electrode / electrolyte physical contact. They hold promise for achieving higher energy densities in more specialized / demanding applications. However, most sulfide SSEs are unstable to lithium metal, exhibiting dendrite growth and solid electrode / electrolyte interface instability during charge-discharge cycles. This leads to numerous problems, such as internal short circuits, increased internal resistance, reduced coulombic efficiency, and eventual battery failure, severely hindering the practical application of all-solid-state lithium metal batteries.

[0003] To alleviate the interface problem between sulfide solid electrolytes and lithium metal anodes, researchers have proposed various strategies and made some progress, including adjusting the composition of sulfide solid electrolytes (such as doping with Li3N, LiF, LiI, etc.), using alloy layers (such as Li-In, Li-Mg, Li-Si, Li-Sn, and Li-Ag, etc.), and constructing artificial SEI films (such as LiF, LiI, and Li3N-LiF, etc.). Among these, the most promising method is to construct a three-dimensional (3D) mixed ionic and electronic conductive interface layer. This interface layer can promote Li... + Rapid transport at the interface induces uniform deposition of metallic lithium within the interface layer, thereby effectively preventing lithium deposition at the interface between the interface layer and the metallic lithium layer, reducing local current density concentration, suppressing lithium dendrite growth, and improving the rate performance / cycle life of all-solid-state batteries.

[0004] An ideal interface layer should have the following characteristics: First, the interface layer itself should be structurally stable, thus facilitating its role as a bridge for ion conduction between the lithium anode and the sulfide solid electrolyte during battery charging and discharging; second, the interface layer should not undergo side reactions with the lithium anode or the sulfide solid electrolyte, ensuring its stable role as an ion transport bridge between the lithium anode and the sulfide solid electrolyte; third, the electronic conductivity of the interface layer should be balanced with the ion diffusion capacity within the interface layer, which helps reduce the formation of lithium dendrites due to insufficient ion diffusion capacity within the interface layer. Summary of the Invention

[0005] This invention addresses the problems in existing technologies by disclosing a carbon-based interface layer and its preparation method. The interface layer of this invention constructs an interconnected 3D ion-conducting network, promoting the formation of Li... + The rapid transport of lithium ions effectively reduces local current density, homogenizes lithium ion flux, and inhibits the growth of lithium dendrites, thereby significantly improving the electrochemical performance of all-solid-state lithium metal batteries under high current density / high areal capacity.

[0006] This invention is achieved through the following technical solution:

[0007] The present invention provides a carbon-based interface layer, the interface layer comprising a lithium-containing layer, the surface of which is provided with a carbon layer, the carbon layer comprising soft carbon and doped nano-sized lithium lanthanum zirconium oxide particles, wherein the doped nano-sized lithium lanthanum zirconium oxide particles are uniformly dispersed in the soft carbon.

[0008] The design of this invention employs soft carbon combined with doped nano-sized lithium lanthanum zirconium oxide particles. The carbon layer isolates the side reactions between the lithium-containing layer and the electrolyte. Furthermore, the soft carbon possesses high ion conductivity and can stably isolate the side reactions between lithium metal and the sulfide solid electrolyte. The nano-sized lithium lanthanum zirconium oxide particles are more uniformly dispersed within the soft carbon, further constructing ion diffusion channels between the soft carbon particles. The lithium lanthanum zirconium oxide solid electrolyte exhibits high ion conductivity, a wide electrochemical window, and good chemical stability, offering advantages in battery cycle life and reliability. However, the lithium lanthanum zirconium oxide solid electrolyte exists in two interconvertible crystal phases: tetragonal and cubic. In the cubic phase structure, the shorter distance between Li-Li particles is beneficial to Li... + The migration of lithium lanthanum zirconium oxide particles results in higher ionic conductivity. Furthermore, the cubic phase exhibits better structural stability than the tetragonal phase, although at certain temperatures, the cubic structure can transform into a tetragonal structure. Doped lithium lanthanum zirconium oxide particles achieve a stable cubic phase structure, which facilitates the consistency between the ionic conductivity of lithium lanthanum zirconium oxide and the lithium-ion diffusion capacity in soft carbon, promoting uniform lithium-ion deposition and thus reducing lithium dendrite formation.

[0009] As a further option, the carbon layer also includes LiC6. LiC6 can also work with lithium lanthanum zirconium oxide particles to improve the ion diffusion rate of the interface layer, so that the electronic conductivity and ionic conductivity of the interface layer can be matched.

[0010] As a further option, the LiC6 can be added directly to the carbon layer or generated by soft carbon and metallic lithium. As a more convenient process, the optimal choice is to generate it by soft carbon and metallic lithium.

[0011] As a further option, the doped nanoscale lithium lanthanum zirconium oxide particles include Li 7-x B1 x La 3-y B2 y Zr 2- z B3 z O 12-u X u One type of particle, wherein B1 is at least one element selected from Ba, Al, Ga, Ge, Fe, B, Zn, and Ta; B2 is at least one element selected from Rb, Y, Bi, Pr, Nd, Pm, Sr, Ba, Ca, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, Ac, and Ta; B3 is at least one element selected from Mg, Sc, Ti, V, Cr, Mn, Ge, Se, Tc, Ru, Rh, Pd, Co, Ni, Cu, Cd, In, Sn, Sb, Te, I, Hf, Tl, Pb, Ce, Pu, Np, Ir, Pt, Y, Ta, Nb, Mo, and W; X is at least one element selected from F, Cl, Br, I, and S; 0 ≤ x < 0.8, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.8, and 0 ≤ u ≤ 0.1; at least one of x, y, z, and u is not 0.

[0012] As a further embodiment, the thickness of the carbon layer is 30μm-100μm. Those skilled in the art generally consider a carbon layer thickness of 30μm-100μm to be a preferred and suitable range in batteries.

[0013] As a further improvement, the thickness of the carbon layer is 30μm-50μm. A carbon layer thickness within this range is beneficial for increasing the ion transport rate of the battery and for improving the overall energy density of the battery.

[0014] As a further embodiment, the raw materials for the carbon layer include soft carbon and doped nano-sized lithium lanthanum zirconium oxide particles, and the lithium-containing layer contains metallic lithium.

[0015] As a further refinement, by mass, the proportion of the doped nano-sized lithium lanthanum zirconium oxide particles in the total mass of the soft carbon and the doped nano-sized lithium lanthanum zirconium oxide particles is greater than 0% and not more than 30%. The presence of doped lithium lanthanum zirconium oxide in the soft carbon facilitates ion diffusion within the carbon layer, promotes uniform lithium deposition, and reduces the formation of lithium dendrites in the interface layer. When the doped lithium lanthanum zirconium oxide particle content exceeds 30%, it leads to the aggregation of the doped lithium lanthanum zirconium oxide particles, resulting in increased grain boundary impedance and decreased ionic conductivity. Therefore, within this range, the doped lithium lanthanum zirconium oxide particles not only improve the ionic conductivity of the battery but also reduce the formation of lithium dendrites, thus contributing to improved battery electrical performance.

[0016] As a further embodiment, the doped nanoscale lithium lanthanum zirconium oxide particles account for 15%-25% of the total mass of the soft carbon and the doped nanoscale lithium lanthanum zirconium oxide particles by weight. The amount of doped lithium lanthanum zirconium oxide particles added contributes to the optimal electrical performance of the battery.

[0017] As a further option, the doped nanoscale lithium lanthanum zirconium oxide particles include Li 7-x B1 x La 3-y B2 y Zr 2- z B3 z O 12-u X u One type of particle, wherein B1 is at least one element selected from Ba, Al, Ga, Ge, Fe, B, Zn, and Ta; B2 is at least one element selected from Rb, Y, Bi, Pr, Nd, Pm, Sr, Ba, Ca, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, Ac, and Ta; B3 is at least one element selected from Mg, Sc, Ti, V, Cr, Mn, Ge, Se, Tc, Ru, Rh, Pd, Co, Ni, Cu, Cd, In, Sn, Sb, Te, I, Hf, Tl, Pb, Ce, Pu, Np, Ir, Pt, Y, Ta, Nb, Mo, and W; X is at least one element selected from F, Cl, Br, I, and S; 0 ≤ x < 0.8, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.8, and 0 ≤ u ≤ 0.1; at least one of x, y, z, and u is not 0.

[0018] As a further solution, the Li 7-x B1 x La 3-y B2 y Zr 2-z B3 z O 12-u X u Particles include Li 7-x B1 x La3- y B2 y Zr 2-z B3 z O 12 One type of particle, wherein B1, B2, and B3 are all Ta; X is at least one element selected from F, Cl, Br, I, and S; 0 ≤ x < 0.8, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.8; u = 0; and at least one of x, y, and z is not 0. Tantalum is particularly suitable for doping lithium lanthanum zirconium oxide particles, especially for improving the ionic conductivity of lithium lanthanum zirconium oxide particles.

[0019] As a further option, the Li 7-x B1 x La 3-y B2 y Zr 2-z B3 z O 12 Particles include Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Particles; wherein B1, B2, and B3 are all Ta; 0 ≤ x < 0.8, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.8; at least one of x, y, and z is not 0.

[0020] As a further option, the soft carbon includes one or more of petroleum coke, needle coke, carbon fiber, coke, carbon microspheres, and graphite;

[0021] As a further improvement, the D50 particle size of the doped nanoscale lithium lanthanum zirconium oxide particles is 280nm-320nm, which is more conducive to their uniform dispersion in the carbon layer.

[0022] As a further option, the raw materials for the carbon layer also include a binder.

[0023] As a further embodiment, the added mass of the binder is 4%-6% of the total mass of soft carbon and doped nano-sized lithium lanthanum zirconium oxide particles.

[0024] As a further embodiment, the adhesive includes one or more of PTFE (polytetrafluoroethylene), polyvinylidene fluoride, styrene-butadiene rubber, alginate, polyacrylonitrile, and sodium carboxymethyl cellulose.

[0025] This invention also provides a method for preparing the interface layer, characterized in that the preparation method includes: weighing soft carbon and nano-sized lithium lanthanum zirconium oxide particles by mass, then adding a binder, hot-pressing to obtain a precursor carbon layer, pressing the precursor carbon layer and the lithium-containing layer together, and then heat-treating to obtain the interface layer of this invention. In this invention, the lithium-containing layer includes a single lithium metal layer or a mixture of lithium metal and other substances.

[0026] As a further embodiment, the hot pressing temperature is 60-80℃; the pressure per unit area during hot pressing is 120MPa-150MPa.

[0027] As a further option, the preparation method also includes preparation in an argon atmosphere.

[0028] As a further step, the preparation method also includes stirring after adding the binder. Those skilled in the art can control the stirring speed according to actual conditions, as long as the binder can effectively adhere to the soft carbon and nano-doped lithium lanthanum zirconium oxide particles.

[0029] As a further embodiment, the pressure per unit area of ​​the compression is 875MPa-1000MPa.

[0030] As a further embodiment, the heat preservation treatment time is 10h-14h, and the heat preservation treatment temperature is 50℃-60℃.

[0031] This invention also provides a negative electrode sheet, positive electrode sheet, or separator having the aforementioned interface layer. The interface layer of this invention is particularly suitable for lithium metal-containing negative electrode sheets. Lithium metal-containing negative electrodes not only suppress the formation of lithium dendrites in the negative electrode but also enhance the ion conductivity, thereby improving the safety and electrical performance of the battery. Lithium metal-containing negative electrodes include lithium metal negative electrodes and pre-lithiated negative electrodes. Pre-lithiated negative electrodes specifically include pre-lithiated graphite, pre-lithiated silicon-carbon, and pre-lithiated silicon-oxygen, etc. When the interface layer is used in a positive electrode sheet or separator, it helps to improve the ion conductivity rate.

[0032] The present invention also provides a battery having the aforementioned negative electrode, positive electrode, or separator, which can be used in 3C products, including but not limited to computers, tablets, mice, mobile phones, digital cameras, Walkmans, electronic dictionaries, digital audio players, smartwatches, MP3 players, MP4 players, radios, and Bluetooth headsets.

[0033] As a further option, the battery includes a liquid-ion battery, a solid-state-ion battery, or a polymer-ion battery.

[0034] As a further embodiment, the solid-state ion battery includes a sulfide solid electrolyte battery.

[0035] The present invention also provides an electrochemical device having the aforementioned negative electrode, positive electrode, or separator, which can be used in end consumer products. The end consumer products claimed include, but are not limited to, mobile phones, laptops, pen input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, and portable printers.

[0036] The present invention also provides an electrochemical device having the aforementioned negative electrode, positive electrode, or separator, which can be used in electrical equipment, including large and small electrical equipment. Small electrical equipment includes consumer products, wearable electronic devices, or portable electronic devices; large electrical equipment includes transportation equipment. Transportation equipment includes, but is not limited to, vehicles such as automobiles, motorcycles, electric bicycles, buses, subways, high-speed trains, airplanes, and ships; wearable electronic devices or portable electronic devices include, but are not limited to, headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, drones, motors, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors. The negative electrode, positive electrode, or separator of the present invention is used in an electrochemical device, which can be housed in an electrical device in the form of an electrochemical device. Typically, the electrochemical device includes a battery pack or / multiple battery modules or / single battery module or / single cell and a management system for controlling them.

[0037] The features and beneficial effects of this invention are as follows:

[0038] (1) The interface layer of the present invention is particularly suitable for use in negative electrode sheets. An interconnected 3D ion-conducting network is constructed inside the interface layer, which promotes the Li + The rapid transmission effectively reduces local current density, homogenizes lithium-ion flux, and inhibits the growth of lithium dendrites.

[0039] (2) The interface layer of the present invention is used in sulfide solid electrolyte batteries, which can not only reduce the side reactions between sulfide solid electrolyte and negative electrode, but also improve the electrical performance of sulfide solid electrolyte batteries. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 The XRD patterns for the examples and comparative examples are shown below. Figure 1 a is the XRD image of the examples and comparative examples before lithiation; Figure 1 b is the XRD pattern of the lithiation in the examples and comparative examples.

[0042] Figure 2SEM images of the embodiments and comparative examples are provided, wherein, Figure 2 a is a SEM image of the comparative micro LLZTO particles at a magnification of 50 μm; Figure 2 b is a SEM image of the comparative micro LLZTO particles at a magnification of 20 μm; Figure 2 c is a SEM image of the comparative micro LLZTO particles at a magnification of 10 μm; Figure 2 d is a SEM image of the comparative micro LLZTO particles at a magnification of 5 μm; Figure 2 e is a SEM image of the nano LLZTO particles in the example at a magnification of 20 μm; Figure 2 f is a SEM image of the nano LLZTO particles in the example at a magnification of 10 μm; Figure 2 g is a SEM image of the nano LLZTO particles in the example at a magnification of 5 μm; Figure 2 h is a SEM image of the nano LLZTO particles in the example at a magnification of 1 μm; Figure 2 i is a comparative SEM image of SC-micro LLZTO at a magnification of 50 μm; Figure 2 j is a SEM image of the comparative SC-micro LLZTO at a magnification of 20 μm; Figure 2 k is a SEM image of the comparative SC-micro LLZTO at a magnification of 10 μm; Figure 2 l is a SEM image of the comparative SC-micro LLZTO at a magnification of 5μm; Figure 2 m is a SEM image of the SC-nanoLLZTO example at a magnification of 50 μm; Figure 2 n is a SEM image of the SC-nano LLZTO sample at a magnification of 20 μm. Figure 2 o is a SEM image of the SC-nano LLZTO example at a magnification of 10 μm; Figure 2 p is a SEM image of the SC-nanoLLZTO example at a magnification of 5 μm.

[0043] Figure 3 The electrical performance of the embodiments and comparative examples is shown, wherein, Figure 3 a is the AC impedance after complete lithiation in the examples and comparative examples; Figure 3 b is the lithium-ion diffusion coefficient versus voltage curve for the examples and comparative examples; Figure 3 c is the Tafel curve of the lithium symmetric battery assembled in the examples and comparative examples at -5°C.

[0044] Figure 4 For the examples and comparative examples, at 4.7 mA cm-2 Deposited at current density of 4.7 mAh cm⁻¹ -2 SEM image of the cross-section after lithium deposition; where, Figure 4 a is a cross-sectional SEM image of the comparative SC at a magnification of 50 μm after lithium deposition; Figure 4 b is a cross-sectional SEM image of the comparative SC at a magnification of 20 μm after lithium deposition; Figure 4 c is a cross-sectional SEM image of the comparative SC at a magnification of 10 μm after lithium deposition; Figure 4 d is a cross-sectional SEM image of the comparative SC-micro LLZTO at a magnification of 50 μm after lithium deposition; Figure 4 e is a cross-sectional SEM image of the comparative SC-micro LLZTO at a magnification of 20 μm after lithium deposition; Figure 4 f is a cross-sectional SEM image of the comparative SC-micro LLZTO at a magnification of 10 μm after lithium deposition; Figure 4 g is a cross-sectional SEM image of SC-nano LLZTO in Example 1 at a magnification of 50 μm after lithium deposition; Figure 4 h is a cross-sectional SEM image of SC-nanoLLZTO in the example at a magnification of 20 μm after lithium deposition; Figure 4 i is a cross-sectional SEM image of SC-nano LLZTO in Example 1 at a magnification of 10 μm after lithium deposition.

[0045] Figure 5 This is a schematic diagram illustrating the lithium deposition mechanism in the examples and comparative examples, wherein, Figure 5 a is a schematic diagram of the lithium deposition mechanism of the comparative SC; Figure 5 b is a schematic diagram of the lithium deposition mechanism of SC-micro LLZTO in comparison. Figure 5 c is a schematic diagram of the lithium deposition mechanism of the SC-nano LLZTO in Example 1.

[0046] Figure 6 For the examples and comparative examples, at 4.7 mA cm -2 Deposited at current density of 4.7 mAh cm⁻¹ -2 SEM image of the cross-section after lithium deposition and corresponding EDS elemental distribution map, wherein, Figure 6 a is a comparative SEM image of SC-micro LLZTO at a magnification of 10 μm; Figure 6 b is a distribution diagram of La element in the comparative SC-micro LLZTO; Figure 6 c is a distribution diagram of Zr element in the proportional SC-micro LLZTO; Figure 6 d is a distribution diagram of C element in the comparative SC-micro LLZTO; Figure 6e is a distribution diagram of Ta element in the proportional SC-microLLZTO; Figure 6 f is a distribution diagram of O element in the proportional SC-micro LLZTO; Figure 6 g is a SEM image of the SC-nano LLZTO sample at a magnification of 10 μm; Figure 6 h is a distribution diagram of the La element in the SC-nano LLZTO embodiment; Figure 6 i is a distribution diagram of Zr element in the SC-nano LLZTO embodiment; Figure 6 j is a distribution diagram of C elements in the embodiment SC-nano LLZTO; Figure 6 k is a distribution diagram of Ta element in the SC-nano LLZTO embodiment; Figure 6 l is a distribution diagram of the O element in the embodiment SC-nanoLLZTO.

[0047] Figure 7 The electrochemical performance of the lithium symmetric batteries assembled in the examples and comparative examples is shown, wherein, Figure 7 a is the critical current density of the battery in the examples and comparative examples; Figure 7 b is the comparison Li in Figure 7 A magnified view of a portion of the image; Figure 7 c is a comparison of SC in Figure 7 A magnified view of a portion of the image; Figure 7 d is the embodiment SC-nano LLZTO in Figure 7 A magnified view of a portion of the image; Figure 7 e is a comparison of SC-micro LLZTO in... Figure 7 A magnified view of a portion of the image; Figure 7 f represents the cycle performance of the lithium symmetric batteries in the examples and comparative examples.

[0048] Figure 8 The electrochemical performance of all-solid-state lithium metal batteries in the examples and comparative examples is shown, wherein, Figure 8 a is the example and comparative example at 0.2 mAh cm⁻¹ -2 Comparison of rate performance under different capacities; Figure 8 b is the 0.2mAh cm⁻¹ of the embodiment and comparative example. -2 Comparison of rate performance under different capacities; Figure 8 c represents the examples and comparative examples at 0.2 mAh cm⁻¹. -2 Rate performance under areal capacity; Figure 8 d is the charge-discharge curve of the SC comparative model at different rates; Figure 8 e is the charge-discharge curve of SC-nano LLZTO at different rates in the embodiment; Figure 8 f is the charge-discharge curve of the proportional SC-micro LLZTO at different rates.

[0049] Figure 9 The electrochemical performance of sulfide all-solid-state lithium metal batteries in the examples and comparative examples is shown below. Figure 9 a is the example and comparative example at 0.2 mAh cm⁻¹ -2 Surface capacity and 30C (6.0mA cm) -2 Comparison of cyclic performance under ( ) conditions; Figure 9 b is the charge-discharge curve of the SC comparative example; Figure 9 c is the charge-discharge curve of the SC-nano LLZTO embodiment; Figure 9 d is the charge-discharge curve of the comparative SC-microLLZTO; Figure 9 e is a comparison of the cycle life of the embodiment with other literature.

[0050] Figure 10 The electrochemical performance of the sulfide all-solid-state lithium metal battery in the example is shown below. Figure 10 'a' represents the rate capability; Figure 10 b represents the charge-discharge curves at different rates; Figure 10 c is a comparison of the rate performance of the embodiment with other literature.

[0051] Figure 11 The electrochemical performance of sulfide all-solid-state lithium metal batteries in the examples and comparative examples is shown below. Figure 11 a is an example at 0.5 mAh cm⁻¹ -2 Charge-discharge curves at different rates for the same surface capacity; Figure 11 b at 0.5mAh cm -2 Comparison of scaling factors between the embodiment and the comparative example under different areal capacities; Figure 11 c is a comparison between the embodiments and other literature; Figure 11 d represents the examples and comparative examples at 25°C (12.5 mA cm⁻¹). -2 Cyclic performance under ( ).

[0052] Figure 12 This invention relates to a high-area-capacity sulfide-based all-solid-state lithium metal battery, wherein... Figure 12 a has a surface capacity of 4.7mAh cm -2 Charge-discharge curves at 1C; Figure 12 b represents the cycle performance of the embodiment; Figure 12 c represents the rate performance of the embodiment; Figure 12 d represents the charge-discharge curves of the embodiment at different rates; Figure 12 e represents the charge-discharge curves of the embodiment under different areal capacities; Figure 12 f is a comparison of the areal capacity of the embodiment with other literature; Figure 12 g is an example with an areal capacity of 7mAh cm -2Charge-discharge curves at 0.1C; Figure 12 h is an example with an areal capacity of 7mAh cm -2 Cyclic performance at 0.1C. Detailed Implementation

[0053] To facilitate understanding of the preparation method of the carbon-based interface layer of the present invention, a more comprehensive description of the preparation method of the carbon-based interface layer of the present invention will be given below, and embodiments of the present invention will be provided, but this does not limit the scope of the present invention.

[0054] In this case, the carbon-based composite layer prepared in the examples and comparative examples is used as an example of a negative electrode to further study the improvement effect on the electrical and safety performance of the battery when the carbon-based composite layer of the present invention is used as a negative electrode. In the examples and comparative examples of the present invention, the lithium-containing layer in the carbon-based composite layer is lithium metal. The soft carbon of the present invention is graphite, hereinafter referred to as SC. In this case, the doped nano-sized lithium lanthanum zirconium oxide particles are selected from nano-sized Li... 6.4 La3Zr 1.4 Ta 0.6 O 12 We will take this as an example for research.

[0055] Example 1:

[0056] In an argon-filled glove box, according to SC: nanoscale Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The mass ratio was 9:1 for weighing, in which nano-sized Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The average particle size is 300 nm. Then, SC and nano-sized Li are added. 6.4 La3Zr 1.4 Ta 0.6 O 12 A 5 wt% PTFE binder was used to bond the two materials together completely by continuous stirring and pressing. The mixture was then rolled to a thickness of 30 μm using a heated roller press to obtain the SC-nano10LLZTO precursor carbon layer. The precursor carbon layer was then pressed together with Li metal under a pressure of 7t (875 MPa) per unit area and placed in an oven at 55°C for 12 hours to allow for complete lithiation, resulting in the interface layer SC-nano10LLZTO-Li.

[0057] Example 2:

[0058] In an argon-filled glove box, according to SC: nanoscale Li 6.4 La3Zr1.4 Ta 0.6 O 12 The mass ratio was 8:2 for weighing, in which nano-sized Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The average particle size is 300 nm. Then, SC and nano-sized Li are added. 6.4 La3Zr 1.4 Ta 0.6 O 12 A 5 wt% PTFE binder was used to bond the two materials together completely by continuous stirring and pressing. The mixture was then rolled to a thickness of 30 μm using a heated roller press to obtain an SC-nano20LLZTO precursor carbon layer (SC-nano LLZTO described in this case is also SC-nano 20LLZTO). The precursor carbon layer was pressed together with Li metal at a pressure of 7t (875 MPa) per unit area and then placed in an oven at 55°C for 12 hours to allow for complete lithiation, resulting in an interface layer SC-nano 20LLZTO-Li (SC-nano LLZTO-Li described in this case is also SC-nano 20LLZTO-Li).

[0059] Example 3:

[0060] In an argon-filled glove box, according to SC: nanoscale Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The mass ratio was 7:3 for weighing, in which nano-sized Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The average particle size is 300 nm. Then, SC and nano-sized Li are added. 6.4 La3Zr 1.4 Ta 0.6 O 12 A 5 wt% PTFE binder was used to bond the two materials together completely by continuous stirring and pressing. The mixture was then rolled to a thickness of 30 μm using a heated roller press to obtain the SC-nano30LLZTO precursor carbon layer. The precursor carbon layer was then pressed together with Li metal under a pressure of 7t (875 MPa) per unit area and placed in an oven at 55°C for 12 hours to allow for complete lithiation, resulting in the interface layer SC-nano30LLZTO-Li.

[0061] Comparative Example 1:

[0062] It has no carbon layer and the negative electrode is a metallic lithium sheet.

[0063] Comparative Example 2:

[0064] The carbon layer (containing only SC and PTFE binder, with the binder added at 5% of the SC mass) is pressed together with Li metal under a pressure of 7t (875MPa) per unit area and placed in an oven at 55℃ for 12h to allow it to be fully lithiated, thus obtaining the interface layer SC-Li.

[0065] Comparative Example 3:

[0066] In an argon-filled glove box, according to SC: micron-sized Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The mass ratio was 8:2 for weighing, in which micron-sized Li... 6.4 La3Zr 1.4 Ta 0.6 O 12 The average particle size is 5 μm. Then, SC and micron-sized Li are added. 6.4 La3Zr 1.4 Ta 0.6 O 12 A 5 wt% PTFE binder was used to bond the two materials together completely by continuous stirring and pressing. The mixture was then rolled to a thickness of 30 μm using a heated roller press to obtain an SC-micro 20LLZTO precursor carbon layer (the SC-micro LLZTO described in this invention is also SC-micro 20LLZTO). The precursor carbon layer was pressed together with Li metal at a pressure of 7t (875 MPa) per unit area and then placed in an oven at 55°C for 12 hours to allow for complete lithiation, resulting in an interface layer SC-micro 20LLZTO-Li (the SC-micro LLZTO-Li described in this invention is also SC-micro 20LLZTO-Li).

[0067] We also used the obtained interface layer as a negative electrode in the battery:

[0068] All electrochemical data in this experiment were obtained by assembling sulfide-based all-solid-state lithium batteries using a Swagelok battery mold with a diameter of 10 mm. The specific battery assembly process is as follows: First, in an argon-filled glove box with a water content <0.1 ppm and an oxygen content <0.1 ppm, 80 mg of Li6PS5Cl solid electrolyte was weighed and carefully placed into a self-made battery mold. A pressure of 1 t (~125 MPa) per unit area was applied for 1 min to form a flat surface. The LCO cathode material used in this experiment was obtained by coating lithium zirconate (LiZrO2). Then, a pre-prepared mass ratio of LZO@LCO:LPSCl:VGCF = 60:35:5 was weighed and evenly sprinkled on the surface of the electrolyte. Here, LZO@LCO represents the product of lithium zirconate coated with lithium cobalt oxide, LPSCl is Li6PS5Cl, and VGCF is vapor-grown carbon fiber. A pressure of 4 t (~500 MPa) per unit area was applied for 1 min. Then, a pre-prepared 30μm SC-nano / microLLZTO interface layer and a 20μm (or 50μm) lithium sheet (low areal capacity: 0.2-0.5mAh / cm²) are sequentially placed on the other side of LPSCl. 2 With 20μm, high surface capacity: 4.7mAh / cm³ 2 Use 50μm or larger, and press together for 1 minute under a pressure of 7t (~875MPa) per unit area. Finally, reduce the pressure to 3t (~375MPa) and tighten the screws in preparation for the next test.

[0069] The symmetrical battery assembly also utilizes a Swagelok battery mold with a diameter of 10 mm. The specific battery assembly process is as follows: First, in an argon-filled glove box with a water content <0.1 ppm and an oxygen content <0.1 ppm, 80 mg of Li6PS5Cl (LPSCl) solid electrolyte is weighed and carefully placed into the self-made battery mold. A pressure of 4 t (~500 MPa) per unit area is applied for 1 min to form a flat plane. Then, a pre-prepared 30 μm SC-nano / micro LLZTO interface layer and a 20 μm (or 50 μm) lithium sheet (low areal capacity: 0.2-0.5 mAh / cm²) are sequentially placed on the upper and lower sides of the LPSCl. 2 With 20μm, high surface capacity: 4.7mAh / cm³ 2 Use 50μm or larger, and press together for 1 minute under a pressure of 7t (~875MPa) per unit area. Finally, reduce the pressure to 3t (~375MPa) and tighten the screws in preparation for the next test.

[0070] The alternating current impedance method involves applying small-amplitude sinusoidal voltage (or current) perturbation signals of different frequencies to a measurement system in equilibrium. By analyzing the frequency signals of the system's response, the impedance of the system under study in different frequency ranges can be deduced. Based on the measured impedance spectrum, the ionic conductivity of sulfide solid electrolytes or interfacial protective layers can be calculated, and electrode process kinetics can also be studied.

[0071] The AC impedance measurements in this paper were performed on a Zennium Pro electrochemical workstation. The frequency range was set to 1 Hz to 8 MHz, and the voltage amplitude was set to 5 mV.

[0072] Galvanostatic charge / discharge measurement is one of the most commonly used electrochemical testing techniques, which can effectively measure the performance of electrochemical materials.

[0073] Critical current density test: The assembled Li / SC-nano / micro LLZTO / LPSCl / SC-nano / microLLZTO / Li symmetric cell was tested for critical current density using the CT3001A Blue Battery testing system. The entire test was conducted using a constant capacity method, with an areal capacity of 0.25 mAh cm⁻¹. -2 The initial and final current densities are 0.25 mA cm⁻¹, respectively. -2 and 20mA cm -2 The circuit was cyclic for 5 cycles at each current density, and the test temperature was 55℃.

[0074] Cycle stability testing: Assembled Li / SC-nano / micro LLZTO / LPSCl / SC-nano / microLLZTO / Li symmetric cells and LZO@LCO / LPSCl / SC-nano / microLLZTO / Li full cells were subjected to constant current charge-discharge tests on a CT3001A blue-electric testing system to study the impact of interface modification on battery cycle stability, thereby evaluating the effectiveness of interface modification. The lithium symmetric cells were tested at 2mA cm⁻¹. -2 Current density and 2mAh cm -2 The tests were conducted at the areal capacity. Full cell testing was performed at 0.2 mAh cm⁻¹. -2 (6.0mA cm -2 ), 0.5mAh cm -2 (12.5mA cm -2 ), 4.7mAhcm -2 (4.7mA cm -2 ), 5mAh cm -2(0.5mA cm -2 ), 7mAh cm -2 (0.7mA cm -2 ), 10mAh cm -2 (1.0mA cm -2 ), 15mAh cm -2 (1.5mA cm -2 The tests were conducted at different surface capacities (current densities), with a voltage range of 2.5V to 4.2V and a test temperature of 55℃. The same rate was used for charge and discharge tests (same rate charge and discharge).

[0075] Rate performance testing: The assembled LCO / LPSCl / SC-nano / micro LLZTO / Li full cells were subjected to constant current charge-discharge tests on the CT3001A blue battery testing system to study the impact of interface modification on the battery rate performance, thereby evaluating the effectiveness of interface modification. The test was conducted at an areal capacity of 0.2 mAh cm⁻¹. -2 Under the test conditions, the current density was 0.2 mA cm⁻¹. -2 0.4mA cm -2 1.0mA cm -2 2.0mA cm -2 3.0mA cm -2 4.0mA cm -2 5.0mA cm -2 6.0mAcm -2 10mA cm -2 The surface capacity is 0.5mAh cm. -2 Under the test conditions, the current density was 0.5 mA cm⁻¹. -2 1.0mA cm -2 2.5mA cm -2 5.0mA cm -2 7.5mA cm -2 10mA cm -2 12.5mA cm -2 The surface capacity is 4.7mAh cm -2 Under the test conditions, the current density was 0.47 mA cm⁻¹. -2 0.94mA cm -2 2.35mA cm -2 4.7mA cm -2 The circuit was cycled 5 times at each current density, with a voltage range of 2.5V to 4.2V, and a test temperature of 55℃. The charge and discharge tests were performed using the same rate (same rate charge and discharge).

[0076] Potentiostatic intermittent titration (PITT) is a measurement method that involves instantaneously changing and maintaining a constant electrode potential while simultaneously recording the change in current over time. It is commonly used in lithium-ion batteries to measure the lithium diffusion coefficient in the electrodes. This paper employs PITT to measure the lithium-ion diffusion coefficient of the SC-nano / microLLZTO interface protective layer, thereby determining the optimal Li3N doping ratio.

[0077] The lithium-ion diffusion coefficient of the SC-nano / micro LLZTO interface protective layer can be calculated using the formula relating the diffusion coefficient (D) to the current (i):

[0078]

[0079] In the formula, D is the diffusion coefficient, i is the current, and L is the electrode thickness.

[0080] The PITT test in this paper was performed on the CT3001A blue electric current test system. First, the open circuit potential was increased by 0.1 mA cm⁻¹. -2 The current density was used to start discharging until the potential reached 0.2V. Then, the potential was instantaneously reduced by 0.02V and maintained for 30 minutes. After that, the potential excitation was removed and a 5-minute relaxation time was allowed until the potential reached 0V. The test temperature was 55℃.

[0081] Tafel polarization curves are commonly used to analyze the exchange current density of lithium deposition. This paper describes the assembly of a Li / SC-nano / micro LLZTO / LPSCl / SC-nano / micro LLZTO / Li symmetric cell, which was tested on a Zennium Pro electrochemical workstation at a scan rate of 0.5 mV / s, a voltage range of -0.1 V to 0.1 V, and a test temperature of -5 °C. The exchange current density of lithium deposition was obtained by fitting the obtained Tafel curves. The intersection of the fitted lines of the linear portions of the anodic and cathodic polarization curves represents the exchange current density of lithium deposition, thus evaluating the effect of interface modification on improving the electrode reaction rate.

[0082] Verification Result Analysis:

[0083] A carbon-based interface layer was successfully prepared using the method of this invention. This interface layer is particularly suitable for use in negative electrodes, and when further applied to sulfide solid electrolyte batteries, the battery's electrical performance was significantly improved, and no lithium dendrites formed in the negative electrode. We believe that the carbon layer in the interface layer may isolate the lithium-containing layer of the interface layer from the side reactions between the lithium-containing layer and the sulfide solid electrolyte, which is beneficial to improving the battery's electrical performance. Building upon this, soft carbon, which exhibits higher ionic conductivity, is used in the carbon layer. To further balance the electronic and ionic conductivity in the interface layer, doped nanoscale lithium lanthanum zirconium oxide particles are mixed with the soft carbon. Firstly, lithium lanthanum zirconium oxide particles themselves possess good ionic conductivity. Secondly, the doped lithium lanthanum zirconium oxide particles not only have a more stable structure, but the ionic conduction direction of these stable particles aligns with the direction of lithium ion diffusion in the soft carbon. Thirdly, the particle size of the doped lithium lanthanum zirconium oxide particles is designed to be nanoscale, which facilitates uniform dispersion of the particles within the pores of the soft carbon particles, creating ion diffusion channels. Fourthly, LiC6 in the interface layer can also work in conjunction with the lithium lanthanum zirconium oxide particles to enhance the ion diffusion rate of the interface layer, ensuring a match between the electronic and ionic conductivity. This further enhances the ion diffusion capacity within the interface layer, promotes uniform lithium ion deposition, and reduces lithium dendrite formation.

[0084] First, we further investigated the coordination between soft carbon and tantalum-doped lithium lanthanum zirconium oxide particles using Example 2 and Comparative Example 3 as examples. Among them, Figure 1 a shows the XRD pattern of the SC-nano / micro LLZTO interface layer. The characteristic peak at 21.3° corresponds to the peak of PE used to isolate air. The crystal structure of nano / micro LLZTO in the interface layer is a pure cubic phase, and all characteristic peaks are consistent with the XRD pattern of pure nano / micro LLZTO powder and the standard PDF card of LLZTO (PDF file No. 80–0457). This proves that LLZTO has been successfully doped into SC and its crystallinity has not changed. Figure 1b shows the XRD pattern of the SC-nano / micro LLZTO interface layer after lithiation. The characteristic peak at 23.5° corresponds to LiC6, and the characteristic peak at 35.8° corresponds to Li metal, indicating that only LiC6 is formed after SC lithiation. LiC6 is beneficial for improving the ion conductivity of the interface layer, and the lithium metal is not completely reacted. In addition, all the characteristic peaks of the cubic phase nano / micro LLZTO in the interface layer after lithiation are still consistent with the XRD pattern of pure nano / micro LLZTO powder and the standard PDF card of LLZTO (PDF file No. 80–0457), and the crystallinity has not changed. It can be seen that the interface layer does not undergo side reactions with lithium metal, and LLZTO is very stable to lithium metal during lithiation and does not react with lithium metal.

[0085] To investigate the distribution of nano / micro LLZTO in the SC-nano / micro LLZTO interface layer, we characterized its surface morphology using SEM. Figure 2 a- Figure 2 As can be seen from d, the micro LLZTO particles are spherical, uniformly distributed, and have an average particle size of approximately 5 μm. Figure 2 e- Figure 2 h represents the surface SEM images of nano LLZTO particles at different magnifications. As can be seen from the images, the nano LLZTO particles are very small, approximately 300 nm in size. Figure 2 i- Figure 2 Image 1 shows the surface SEM images of the SC-micro LLZTO interface layer at different magnifications. The images reveal a highly uneven distribution of micro LLZTO particles within the SC. Due to their relatively large size (5 μm), the particles are primarily distributed on the surface of the SC particles, with fewer particles in the interstitial spaces, resulting in significant gaps between the SC particles. Conversely, from... Figure 2 m- Figure 2 As can be seen from p, the surface of the SC-nano LLZTO interface layer is very dense, with almost no gaps between SC particles. This indicates that the small-sized nano LLZTO particles (300 nm) are uniformly distributed on the surface and in the gaps between the SC particles, forming an interconnected ion-conducting network that promotes Li... + Fast transmission.

[0086] We investigated the effect of nano / micro LLZTO doping on the improvement of interfacial layer ionic conductivity by assembling electron-blocking cells. Figure 3'a' represents the AC impedance of the SC-nano / micro LLZTO interface layer after complete lithiation at 55°C and a pressure of 7t (~875MPa) per unit area. The figure shows that after complete lithiation, the SC-nano LLZTO interface layer has the lowest impedance, followed by the SC-micro LLZTO interface layer, with the SC interface layer exhibiting the highest impedance. This can be attributed to the smaller particle size and higher specific surface area of ​​nano LLZTO, which facilitates more uniform distribution within the SC and increases contact between nano LLZTO particles, forming an interconnected three-dimensional ionic conductive network. This network synergizes with the LiC6 generated during lithiation, jointly promoting rapid lithium-ion transport. Therefore, the SC-nano LLZTO interface layer exhibits the lowest impedance and significantly improved ionic conductivity. While micro LLZTO has a relatively uneven distribution within the SC and cannot form an interconnected ionic conductive network, its high ionic conductivity allows lithium ions to be rapidly transported via the LiC6-LLZTO pathway, thus also improving the ionic conductivity of the interface layer to some extent, resulting in a lower impedance than the SC interface layer. Therefore, it can be seen that doping LLZTO into SC can significantly improve the ionic conductivity of the interface layer, and the following rule is observed: SC-nano LLZTO > SC-micro LLZTO > SC.

[0087] Figure 3 Figure b shows the lithium-ion diffusion coefficient versus voltage curve of the SC-nano / micro LLZTO interface layer. As can be seen from the figure, the lithium-ion diffusion coefficient of the SC-nano / micro LLZTO interface layer exhibits the following trend under different voltages: SC-nano LLZTO > SC-micro LLZTO > SC. This indicates that the doping of LLZTO effectively modulates the ion dynamics in the interface layer, promotes rapid lithium-ion diffusion, and significantly improves the lithium-ion diffusion coefficient within the interface layer. This is mainly attributed to the three-dimensional lithium-ion diffusion channels of cubic LLZTO, allowing lithium ions to diffuse rapidly along the LLZTO ion-conducting network, thereby increasing the lithium-ion diffusion coefficient of the interface layer. Furthermore, the nano LLZTO is more uniformly distributed and interconnected within the SC, resulting in the highest lithium-ion diffusion coefficient for the SC-nano LLZTO interface layer.

[0088] Figure 3c shows the Tafel curve of a lithium-ion symmetric battery assembled using an SC-nano / micro LLZTO interface layer at -5°C. Since a very large current would be generated at 0.05V at room temperature, causing a short circuit, the entire test was conducted at -5°C. The results show that the Li anode with SC-nano LLZTO as the interface layer (SC-nano LLZTO-Li) has the highest exchange current density (1.291 cm⁻¹). -2 This is because nano LLZTO is more uniformly distributed in SC, and the three-dimensional LLZTO ion-conducting network improves the lithium-ion transport rate and increases the number of lithium metal deposition sites. The exchange current density of SC-micro LLZTO is relatively small (0.606 mA cm⁻¹). -2 However, it is still superior to the exchange current density of SC-Li (0.396 mA cm⁻¹). -2 The exchange current density of bare Li (0.291 mA cm⁻¹) and bare Li -2 This further confirms the consistency of the pattern that SC-nano LLZTO > SC-micro LLZTO > SC.

[0089] To evaluate the lithium deposition behavior of the SC-nano / micro LLZTO interface layer, the deposition rate of the SC-nano / micro LLZTO interface layer at 4.7 mA cm⁻¹ was investigated using SEM. -2 Deposited at current density of 4.7 mAh cm⁻¹ -2 The cross-sectional morphology of lithium. Figure 4 a- Figure 4 c represents the SC interface layer deposited at 4.7 mAh cm⁻¹ -2 SEM images of the cross-section after lithium removal, from Figure 4 a- Figure 4 In diagram b, it can be clearly observed that after lithium deposition, a large number of lithium dendrites pierced the LPSCl electrolyte, and there are still a large number of voids between the SC particles (e.g., Figure 4 As shown in c), there is no lithium metal, indicating that lithium ions directly gain electrons at the SC / LPSCl interface to form lithium dendrites, which then grow into the LPSCl electrolyte and eventually penetrate the solid electrolyte. This is mainly because SC has a high electronic conductivity and a low lithium-ion diffusion coefficient. Under high current density, electrons will quickly reach the SC / LPSCl electrolyte interface, and Li... + The inability to replenish the charge leads to localized charge buildup, inducing lithium dendrite formation, which eventually punctures the solid electrolyte, causing a short circuit in the battery. A schematic diagram of the lithium deposition mechanism at the SC interface layer is shown below. Figure 5 As shown in a.

[0090] Figure 4 d- Figure 4f represents the SC-micro LLZTO interface layer deposited at 4.7 mAh cm⁻¹. -2 SEM images of the cross-section after lithium removal, from Figure 4 d- Figure 4 In image e, it can be clearly observed that after lithium deposition, a large number of lithium dendrites pierced the LPSCl electrolyte, and there was also a large amount of lithium metal deposition inside the interface layer, but there were still a large number of voids between the particles (e.g. Figure 4 (as shown in f), this indicates that lithium metal is deposited not only on the surface of particles or in the voids within the interface layer, but also unevenly deposited at the interface between LPSCl and the interface layer, forming lithium dendrites that pierce the LPSCl electrolyte. Combined with... Figure 6 a- Figure 6 It can be observed that La, Zr, Ta, and O elements are relatively scarcely dispersed within the interface layer and are highly non-uniform. This demonstrates the non-uniform dispersion of micro LLZTO particles in the interface layer and the presence of Li. + The obstruction and migration of lithium dendrites lead to unfavorable electrodeposition behavior. Under high deposition rates and high current densities, a "point effect" occurs, disrupting the spherical growth pattern of lithium metal around LLZTO particles and transforming it into dendritic growth, forming lithium dendrites that eventually penetrate the interface layer and grow into the solid electrolyte. Therefore, the SC-micro LLZTO interface layer can only inhibit lithium dendrite growth to a certain extent at relatively low current densities; at high current densities, lithium dendrites will still form. A schematic diagram of the lithium deposition mechanism of the SC-micro LLZTO interface layer is shown below. Figure 5 As shown in b.

[0091] Figure 4 g- Figure 4 i represents the SC-nano LLZTO interface layer deposited at 4.7 mAh cm⁻¹ -2 The cross-sectional SEM image of the lithium deposition layer shows that the particles within the interface layer are almost fused together, forming a very dense structure without any voids. Furthermore, no lithium metal deposition or lithium dendrites were observed at the SC / LPSCl interface. This indicates that the lithium metal is deposited within the gaps of the SC-nano LLZTO interface layer, which significantly increases the deposition sites for lithium metal, effectively reducing the local current density and suppressing lithium dendrite formation. Combined with... Figure 6 g- Figure 6La, Zr, Ta, and O elements were observed to be uniformly distributed in the interface layer, while C element distribution was significantly uneven, with some missing regions that could not be identified by LLZTO. It can be inferred that lithium metal may have been deposited on the surface and interstices of SC particles, forming a three-dimensional LLZTO network. This caused some SC particles to be masked by lithium metal, making it impossible for EDS to distinguish Li elements. Therefore, the missing regions may be SC particles masked by Li metal. This is mainly because doping the SC interface layer with high ionic conductivity, high diffusion coefficient, and stability of cubic nano LLZTO increases the ionic conductivity and ion diffusion rate of the interface layer while decreasing the electronic conductivity. The higher ion diffusion rate can promote Li diffusion under the driving force of concentration. + Diffusion occurs towards the negative electrode, and the lower electronic conductivity can increase the potential difference at the negative electrode, thus benefiting Li. + Diffusion provides a greater driving force. On the other hand, a three-dimensional LLZTO ion-conducting network is formed within the interface layer, Li + Lithium deposits rapidly transport along the LLZTO ion-conducting network and nucleate and grow on the LLZTO ion-conducting network within the interface layer, effectively suppressing lithium dendrite growth. However, due to the high electronic conductivity of the SC interface layer, electrons rapidly reach the interface between the soft carbon and the electrolyte under high current, causing localized charge accumulation, inducing lithium dendrite formation, and ultimately piercing the solid electrolyte, leading to a battery short circuit. A schematic diagram of the lithium deposition mechanism of the SC-nano LLZTO interface layer is shown below. Figure 5 As shown in c.

[0092] In summary, doping LLZTO into SC can significantly improve the electrochemical performance of the interface layer, such as ionic conductivity, lithium-ion diffusion coefficient, and lithium deposition exchange current density, and all follow the following rule: SC-nano LLZTO > SC-microLLZTO > SC.

[0093] To investigate the interfacial stability of LPSCl / Li optimized with an SC-nano / micro LLZTO interface layer, we assembled a Li / SC-nano / micro LLZTO / LPSCl / SC-nano / micro LLZTO / Li symmetric cell with an areal capacity of 0.25 mAh cm⁻¹. -2 The critical current density test was then performed. Figure 7 As can be seen from the SC-nano LLZTO interface layer, the highest CCD display reaches 20mA. -2 The lithium symmetry of the SC-micro LLZTO and SC interface layers is at 16 mA cm⁻¹. -2 and 10mA cm -2 A significant voltage drop was observed at current densities (e.g.) Figure 7 e and Figure 7 (as shown in c), while the bare Li symmetric cell only reaches 3 mA / cm². -2 A voltage drop occurs at current densities (e.g.) Figure 7 (As shown in b) This is mainly because LPSCl electrolyte readily undergoes side reactions with Li metal, generating undesirable ionic conductors such as Li3P, leading to increased interfacial resistance. Furthermore, the poor interfacial contact between LPSCl and Li results in uneven lithium metal deposition, increased local current density, and accelerated lithium dendrite growth. Clearly, the LPSCl / Li interface optimized with an SC-nano LLZTO interfacial layer exhibits the best electrochemical stability. This is primarily due to the high lithium-ion diffusion coefficient of the SC-nano LLZTO interfacial layer, which separates the LPSCl electrolyte and Li metal, effectively preventing chemical / electrochemical reactions between them, promoting rapid lithium-ion transport, inducing lithium metal deposition on the LLZTO ion-conducting network within the interfacial layer, reducing local current density, homogenizing lithium-ion flux, thereby increasing the critical current density and suppressing lithium dendrite growth. Furthermore, the SC-nano LLZTO interface layer exhibits good wettability and the highest ionic conductivity, improving the interfacial contact of LPSCl / Li and significantly reducing the interfacial resistance of LPSCl / Li. Therefore, the Li / SC-nano LLZTO / LPSCl / SC-nano LLZTO / Li symmetric cell can withstand even 20 mA cm⁻¹. -2 At extremely high current densities, the polarization voltage is also extremely low (0.06V) (e.g. Figure 7 (as shown in d). Conversely, the uneven dispersion of micro LLZTO particles in the SC-micro LLZTO interface layer and Li + Blockage migration tends to cause unfavorable electrodeposition behavior. At high current densities, it easily leads to a "sharp effect," disrupting the spherical growth of lithium metal around LLZTO particles and transforming it into dendritic growth, forming lithium dendrites that eventually penetrate the interface layer and grow into the solid electrolyte. Therefore, although the CCD of the SC-micro LLZTO interface layer is higher than that of the SC interface layer, it can only suppress lithium dendrite growth to a certain extent at relatively low current densities; at high current densities, lithium dendrites will still form. The CCD of the SC interface layer is only 10 mA cm⁻¹. -2 This is due to the high electronic conductivity of the SC interface layer, Li + The diffusion rate is relatively slow; at high current densities, electrons will rapidly reach the SC / LPSCl interface, Li + If there is not enough time to replenish the charge, local charge buildup will occur, inducing the formation of lithium dendrites, which will eventually puncture the solid electrolyte and cause the battery to short-circuit.

[0094] In addition, from Figure 7 As can be seen from f, the lithium-symmetric battery optimized with the SC-nano LLZTO interface layer exhibits the best cycle stability, achieving stable cycling for over 2000 hours (1000 cycles) with the lowest initial polarization voltage (8mV) and final polarization voltage (11mV). Conversely, while the lithium-symmetric battery with the SC-micro LLZTO interface layer has an initial polarization voltage (10mV) similar to that of the SC-nano LLZTO interface layer (8mV), it shows significant voltage fluctuations after 540 hours of cycling, followed by a sharp increase in polarization voltage to 0.5V, then a voltage drop, ultimately leading to a short circuit. The lithium-symmetric battery with the SC interface layer shows a continuously increasing polarization voltage from the initial cycling stage, short-circuiting after 798 hours, with a final polarization voltage as high as 52mV. This is mainly due to the uneven deposition and stripping of lithium, resulting in dead lithium, which increases the interface resistance, leading to a continuous increase in polarization voltage and ultimately a short circuit. The bare Li symmetric cell short-circuited after only 3 cycles and exhibited a very high initial polarization voltage (20mV). In addition, a micro-short circuit occurred during the first cycle.

[0095] In summary, the lithium-ion symmetric battery optimized with an SC-nano LLZTO interface layer exhibits the highest critical current density and best cycle stability. Furthermore, the electrochemical performance of different interface layer ratios still follows the order: SC-nano LLZTO > SC-micro LLZTO > SC > Li. Therefore, optimizing the LPSCl / Li interface with an SC-nano LLZTO interface layer demonstrates the best chemical / electrochemical stability, proving that the SC-nano LLZTO interface layer can effectively stabilize the LPSCl / Li interface, avoid interfacial side reactions, improve interfacial contact, and suppress lithium dendrite growth, thereby significantly improving the battery's electrochemical performance.

[0096] To further compare the electrochemical performance of the SC-nano / micro LLZTO interface layer, a series of electrochemical characterizations were performed. We investigated the optimal ratio of the SC-nano / micro LLZTO (a = 0, 10, 20, and 30 wt%) interface layer by evaluating the rate performance of all-solid-state lithium metal batteries using LZO@LCO / LPSCl / SC-nano / micro aLLZTO / Li (a = 0, 10, 20, and 30 wt%). Here, 'a' represents the mass percentage of nano-sized lithium lanthanum zirconium oxide particles in the total mass of soft carbon and nano-sized lithium lanthanum zirconium oxide particles. Figure 8 a shows that at 0.2mAh cm -2In terms of areal capacity, LZO@LCO / LPSCl / SC-nano20LLZTO / Li exhibits the best rate performance, providing the highest discharge specific capacity (89.9 mAh g) at a high rate of 50C. -1 Furthermore, it was observed that the discharge specific capacity of LZO@LCO / LPSCl / SC-nano aLLZTO / Li (a = 0, 10, 20, and 30 wt%) all-solid-state lithium metal batteries increased and then decreased with increasing LLZTO doping content. This indicates that there is a threshold for LLZTO doping content; exceeding this threshold leads to a decrease in the electrochemical performance of the interface layer. This can be attributed to the fact that the small LLZTO particles themselves have a large specific surface area and high surface energy. Therefore, when the LLZTO doping content exceeds 20 wt%, they tend to spontaneously aggregate, leading to increased particle size, increased grain boundary impedance, and decreased ionic conductivity, severely affecting the electrochemical performance of the interface layer. Similar to the SC-nano aLLZTO (a = 0, 10, 20, and 30 wt%) interface layer, the SC-micro aLLZTO (a = 0, 10, 20, and 30 wt%) interface layer also exhibited the same trend, and at 0.2 mAh cm⁻¹... -2 In terms of areal capacity, LZO@LCO / LPSCl / SC-micro20LLZTO / Li also exhibits the best rate performance, providing the highest discharge specific capacity (82.2 mAh g) at a high rate of 50C. -1 )(like Figure 8 (As shown in b). We compare the rate performance of the optimal ratio of SC-nano LLZTO (SC-nano 20LLZTO) and SC-micro LLZTO (SC-micro 20LLZTO) interface layers, from... Figure 8 c- Figure 8 As can be seen in f, the interface layers of both SC-nano LLZTO and SC-micro LLZTO can reach 50°C (10mA cm⁻¹). -2 The SC-nano LLZTO interface layer exhibits high discharge rates, but its discharge specific capacity at 50C is only 89.9 mAh g⁻¹. -1 The discharge specific capacity is significantly higher than that of the SC-microLLZTO interface layer (82.2 mAh g). -1 The rate capability of the SC interface layer, which is not doped with LLZTO, is relatively high, but the rate performance is poor, reaching only 30C, and it can only provide a low discharge specific capacity (63.8 mAh g). -1 Bare Li exhibits the worst rate performance, providing only the lowest specific capacity (20.1 mAh g⁻¹) at 30C. -1Therefore, it can be concluded that the SC-nano LLZTO interface layer has the best rate performance. We further optimized the ratio of doped nano-sized lithium lanthanum zirconium oxide to the total mass of soft carbon and doped nano-sized lithium lanthanum zirconium oxide to be 15%-25%.

[0097] In addition, we compared the cycling performance of the optimal ratio of SC-nano LLZTO and SC-micro LLZTO interface layers, such as... Figure 9 a- Figure 9 As shown in figure d, the LZO@LCO / LPSCl / SC-nano LLZTO / Li all-solid-state lithium metal battery achieves an ultra-long cycle life of 20,000 cycles at a high rate of 30C, and still provides 82.6 mAh g after 20,000 cycles. -1 The specific capacity has a capacity retention rate of nearly 80%. Figure 9 a and Figure 9 (As shown in c). In contrast, the specific capacity of the SC-micro LLZTO interface layer decayed to 8.5 mAh g after 12798 cycles. -1 The capacity retention rate is only 0.9% ( Figure 9 a and Figure 9 As shown in d), the specific capacity of the SC interface layer almost decays to zero after 270 cycles. Figure 9 a and Figure 9 (As shown in b). This demonstrates that the SC-nano LLZTO interface layer exhibits the best cycling performance. Furthermore, compared to the cycling performance of solid-state batteries reported in the literature, the Li anode with the SC-nano LLZTO interface layer demonstrates unprecedented cycling performance, far exceeding the current highest level (as shown in b). Figure 9 (as shown in e).

[0098] Furthermore, the SC-nano LLZTO interface layer has a high exchange current density (1.291 cm⁻¹). -2 It possesses good ion conductivity and therefore exhibits good rate performance. Surprisingly, even at an ultra-high rate of 175C, the LZO@LCO / LPSCl / SC-nano LLZTO / Li all-solid-state lithium metal battery still delivers 38.2 mAh g⁻¹. -1 Specific capacity ( Figure 10 a- Figure 10 (As shown in b). Compared with the rate performance of solid-state batteries reported in the literature, the Li anode with the SC-nano LLZTO interface layer exhibits an unprecedented maximum charge rate, far exceeding the current highest level ( Figure 10 c).

[0099] In summary, the SC-nano LLZTO interface layer exhibits the best rate performance and cycling performance. This is attributed to the high ionic conductivity, high diffusion coefficient, and stable cubic nano LLZTO doping within the SC interface layer. This forms a three-dimensional LLZTO ion-conducting network within the interface layer, enhancing the ionic conductivity and ion diffusion rate while simultaneously reducing electronic conductivity, thus driving lithium-ion transport into the SC-nano LLZTO interface layer. Therefore, lithium metal can nucleate and grow on the LLZTO ion-conducting network within the SC-nano LLZTO interface layer, effectively suppressing lithium dendrite growth and achieving an ultra-high rate capability of 175C and a cycling performance of 30C (6 mA cm⁻¹). -2 ) under 20,000 ultra-long cycle.

[0100] To further compare the electrochemical performance of the SC-nano / micro LLZTO interface layer at high current densities, we further increased the areal capacity and investigated the performance of the LZO@LCO / LPSCl / SC-nano / micro LLZTO / Li all-solid-state lithium metal battery at 0.5 mAh cm⁻¹. -2 Electrochemical performance at areal capacity. From Figure 11 a- Figure 11 b shows that at 0.5mAh cm -2 At the areal capacity level, LZO@LCO / LPSCl / SC-nano / micro LLZTO / Li all-solid-state lithium metal batteries can all reach a maximum current density of 25C, which translates to a high current density of 12.5 mA cm⁻¹. -2 The SC interface layer can only reach 15°C, while bare Li can only reach 5°C. This translates to an amplification of only 7.5 mA cm⁻¹ for both the SC interface layer and bare Li. -2 and 2.5mA cm -2 The low current density. However, the SC-nanoLLZTO interface layer can provide a discharge specific capacity (92.3 mAh g) at a 25C rate. -1 The concentration of 70.9 mAh g is significantly higher than that of the SC-micro LLZTO interface layer. -1 This further demonstrates that the SC-nano LLZTO interface layer still exhibits better rate performance than the SC-micro LLZTO interface layer, even at high current densities. Compared with the current densities of solid-state batteries reported in the literature, the Li anode with SC-nano LLZTO as the interface layer demonstrates an ultra-high limiting current density (12.5 mA cm⁻¹). -2 It far exceeds the current highest level. Figure 11c). Furthermore, the LZO@LCO / LPSCl / SC-nano LLZTO / Li all-solid-state lithium metal battery achieved a 12.5 mA cm⁻¹ performance. -2 Achieving 4000 cycles at a high current density (high rate) at (25C), and still providing 90.1 mAh g after 4000 cycles. -1 The specific capacity has a capacity retention rate as high as 98.3%. Figure 11 (As shown in d). In contrast, the specific capacity of the SC-micro LLZTO interface layer decayed to 40 mAh g after 4000 cycles. -1 The capacity retention rate was only 56.5% ( Figure 11 d). This further demonstrates that the SC-nano LLZTO interface layer still exhibits better cycling performance than the SC-micro LLZTO interface layer, even at high current densities.

[0101] In summary, the SC-nano LLZTO interface layer maintains excellent electrochemical performance even at high current densities. This is mainly attributed to the SC-nano LLZTO interface layer effectively separating LPSCl / Li, thus preventing side reactions between them. Furthermore, the three-dimensional LLZTO ion-conducting network within the interface layer promotes rapid lithium-ion transport, induces lithium metal deposition on the LLZTO network within the interface layer, reduces local current density, and homogenizes lithium-ion flux, thereby achieving a current density of 12.5 mA cm⁻¹. -2 It features high current density and a long cycle life of 4000 cycles (capacity retention of 98.3%).

[0102] from Figure 12 a- Figure 12 As can be seen from b, the LZO@LCO / LPSCl / SC-nano LLZTO / Li all-solid-state lithium metal battery can achieve a capacity of 4.7 mAh cm⁻¹. -2 The areal capacity and 4.7 mA cm -2 It can stably cycle for 350 cycles at high current density and still maintain a capacity retention of up to 94.4%, and can still provide 113.5 mAh g even at 1C. -1 Specific capacity ( Figure 12 c- Figure 12 d). In addition, by Figure 12 As can be seen, even at a 5mAh cm⁻¹, the LZO@LCO / LPSCl / SC-nano LLZTO / Li all-solid-state lithium metal battery... -2 and 10mAh cm -2 Even at 0.1C, it still provides a capacity of 127.7mAh g. -1 and 124.1mAh g-1 The specific capacity, when the surface capacity increases to 15mAh cm⁻¹ -2 At 0.1C, it can still provide 120.7mAh g. -1 Specific capacity. To our knowledge, 15mAh cm⁻¹ -2 This is the highest reported areal capacity value for all-solid-state, semi-solid-state, and polymer solid-state lithium metal batteries to date. Figure 12 f). Furthermore, at 7mAh cm⁻¹ -2 At the same areal capacity, the LZO@LCO / LPSCl / SC-nano LLZTO / Li all-solid-state lithium metal battery can also achieve 0.1C (0.7mA cm⁻¹). -2 Achieving a long cycle of 150 revolutions ( ) Figure 12 g- Figure 12 h). Therefore, it can be concluded that the LZO@LCO / LPSCl / SC-nano LLZTO / Li all-solid-state lithium metal battery can achieve a 15mAh cm⁻¹. -2 Ultra-high surface capacity and high capacity (7mAh cm) -2 Long cycling (150 cycles). This further demonstrates that the SC-nano LLZTO interface layer can effectively stabilize the LPSCl / Li interface, avoid interfacial side reactions, improve interfacial contact, and inhibit lithium dendrite growth, thereby greatly improving the electrochemical performance of the battery.

[0103] In summary, this work has developed a hybrid conductive interface protective layer with a high lithium-ion diffusion coefficient by combining soft carbon with cubic nano-LLZTO. This layer promotes uniform deposition of lithium metal within the interface layer and inhibits lithium dendrite growth at ultra-high current densities. The high ionic conductivity and diffusion rate of LLZTO, uniformly distributed on the surface and in the interstices of SC particles, form a rapid three-dimensional lithium-ion transport network, promoting lithium-ion migration into the SC-nano LLZTO interface layer. Lithium ions gain electrons on the LLZTO network within the interface layer to form metallic lithium, effectively preventing rapid deposition of lithium dendrites at the interface between the negative electrode and the electrolyte. Therefore, lithium symmetric batteries at 0.25 mAh cm⁻¹ exhibit improved conductivity and diffusion rates. -2 It showed 20mA cm -2 The ultra-high critical current density.

[0104] The LZO@LCO / LPSCl / SC-nano LLZTO / Li all-solid-state lithium metal battery assembled using an SC-nano LLZTO interface layer can achieve an ultra-long cycle life of 20,000 cycles at a high rate of 30C, and still provides 82.6 mAh g / L after 20,000 cycles. -1 The specific capacity is high, and the capacity retention is close to 80%. Even at 12.5 mA cm⁻¹ -2It can achieve a long cycle life of 4000 cycles even at ultra-high current density, and can still provide 90.1mAh g after 4000 cycles. -1 The specific capacity is as high as 98.3%, and the capacity retention is as high as 98.3%. The current density and cycle life both break the highest levels reported to date for solid-state batteries (8.6 mA / cm²). -2 (and 10,000 cycles). Furthermore, at 4.7mAh cm⁻¹ -2 Despite its high surface capacity, it can still operate at 1C (4.7 mA cm⁻¹). -2 After 350 stable cycles, the capacity retention rate reached 94.4%. (4.7 mA cm) -2 Solid-state lithium metal batteries have a high areal capacity (>1mAh cm⁻¹). -2 It also achieved a maximum value of 15mAh cm⁻¹. -2 The ultra-high areal capacity breaks the current record for solid-state lithium metal batteries. Furthermore, the SC-nano LLZTO interface layer proposed in this study is composed of low-cost composite materials, making it easy to mass-produce and providing new possibilities for the large-scale production of all-solid-state lithium metal batteries.

[0105] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0106] Figure 9 References for the parameters of e:

[0107] 1. Ji X, Hou S, Wang P, He X, Nan P, Chen J, et al. Solid-State ElectrolyteDesign for Lithium Dendrite Suppression. Advanced Materials 2020.

[0108] 2.Wan H, Zhang J, Xia J, Ji X, He

[0109] 3.Xu R,FudongJi,XiaoFan,XiulinTu,JiangpingWang,Chunsheng.Interfaceengineering of sulfide electrolytes for all-solid-state lithiumbatteries.Nano Energy 2018,53.

[0110] 4.D.H.Kim et al.,Infiltration ofsolution-processable solidelectrolytes into conventional Li-ion-battery electrodes for all-solid-stateLi-ion batteries.Nano letters 17,3013-3020(2017).

[0111] 5.Kim C,Kim J,Park J,Kim J,Lee S,Sun S,et al.Ion-Conducting ChannelImplanted Anode Matrix for All-Solid-State Batteries with High RateCapability and Stable Anode / Solid Electrolyte Interface.AdvancedEnergyMaterials 2021,11(40).

[0112] 6.Liang J,Li X,Zhao Y,Goncharova LV,Wang G,Adair KR,et al.In SituLi3PS4Solid-State Electrolyte Protection Layers for Superior Long-Life andHigh-Rate Lithium-Metal Anodes.AdvancedMaterials 2018,30(45).

[0113] 7.Lee Y-G,Fujiki S,Jung C,Suzuki N,Yashiro N,Omoda R,et al.High-energy long-cycling all-solid-state lithium metal batteries enabled bysilver-carbon composite anodes.NatureEnergy 2020,5(4):299-308.

[0114] 8.Lee K,Han S,Lee J,Lee S,Kim J,Ko Y,et al.Multifunctional Interfacefor High-Rate and Long-Durable Garnet-Type Solid Electrolyte in Lithium MetalBatteries.Acs Energy Letters 2022,7(1):381-389.

[0115] 9.Chen Y,Li W,Sun C,Jin J,Wang Q,Chen X,et al.Sustained Release-Driven Formation ofUltrastable SEI between Li6PS5Cl and Lithium Anode forSulfide-Based Solid-State Batteries.AdvancedEnergy Materials 2021,11(4).

[0116] 10.Tan DHS,Chen Y-T,Yang H,Bao W,Sreenarayanan B,Doux J-M,etal.Carbon-free high-loading silicon anodes enabled by sulfide solidelectrolytes.Science 2021,373(6562):1494.

[0117] 11. Zhou L, Zuo T-T, Kwok CY, Kim SY, Assoud A, Zhang Q, et al. High areal capacity, long cycle life 4 V ceramic all-solid-state Li-ion batteries enabled by chloride solid electrolytes. Nature Energy 2022, 7(1): 83-93.

[0118] 12. Cheng Z, Pan H, Li F, Duan C, Liu H, Zhong H, et al. Achieving long cycle life for all-solid-state rechargeable Li-I₂ battery by a confined dissolution strategy. Nature Communications 2022, 13(1).

[0119] 13. Peng L, Yu C, Zhang Z, Ren H, Zhang J, He Z, et al. Chlorine-rich lithium argyrodite enabling solid-state batteries with capabilities of high voltage, high rate, low-temperature and ultralong cyclability. Chemical Engineering Journal 2022, 430.

[0120] 14. Ye L, Li X. A dynamic stability design strategy for lithium metal solid state batteries. Nature 2021, 593(7858): 218.

[0121] Figure 10 C References:

[0122] 1.Xu R,FudongJi,XiaoFan,XiulinTu,JiangpingWang,Chunsheng.Interfaceengineering of sulfide electrolytes for all-solid-state lithiumbatteries.Nano Energy 2018,53.

[0123] 2.Ji X,Hou S,Wang P,He X,Nan P,Chen J,et al.Solid-State ElectrolyteDesign for Lithium Dendrite Suppression.AdvancedMaterials 2020.

[0124] 3.Wan H,Zhang J,Xia J,Ji X,He X,Liu S,et al.F and N Rich SolidElectrolyte for Stable All-Solid-State Battery.AdvancedFunctionalMaterials2022,32(15).

[0125] 4.Kim C,Kim J,Park J,Kim J,Lee S,Sun S,et al.Ion-Conducting ChannelImplanted Anode Matrix for All-Solid-State Batteries with High RateCapability and Stable Anode / Solid Electrolyte Interface.AdvancedEnergyMaterials 2021,11(40).

[0126] 5.Chen Y,Li W,Sun C,Jin J,Wang Q,Chen X,et al.Sustained Release-Driven Formation ofUltrastable SEI between Li6PS5Cl and Lithium Anode forSulfide-Based Solid-State Batteries.AdvancedEnergy Materials 2021,11(4).

[0127] 6.Liang J,Li X,Zhao Y,Goncharova LV,Wang G,Adair KR,et al.In SituLi3PS4Solid-State Electrolyte Protection Layers for Superior Long-Life andHigh-Rate Lithium-Metal Anodes.AdvancedMaterials 2018,30(45).

[0128] 7.Lee Y-G,Fujiki S,Jung C,Suzuki N,Yashiro N,Omoda R,et al.High-energy long-cycling all-solid-state lithium metal batteries enabled bysilver-carbon composite anodes.NatureEnergy 2020,5(4):299-308.

[0129] 8.Tan DHS,Chen Y-T,Yang H,Bao W,Sreenarayanan B,Doux J-M,etal.Carbon-free high-loading silicon anodes enabled by sulfide solidelectrolytes.Science 2021,373(6562):1494.

[0130] 9.Lee K,Han S,Lee J,Lee S,Kim J,Ko Y,et al.Multifunctional Interfacefor High-Rate and Long-Durable Garnet-Type Solid Electrolyte in Lithium MetalBatteries.Acs Energy Letters 2022,7(1):381-389.

[0131] 10.Zhou L,Zuo T-T,Kwok CY,Kim SY,Assoud A,Zhang Q,et al.High arealcapacity,long cycle life 4V ceramic all-solid-state Li-ion batteries enabledby chloride solid electrolytes.NatureEnergy 2022,7(1):83-93.

[0132] 11.Cheng Z,Pan H,Li F,Duan C,Liu H,Zhong H,et al.Achieving long cyclelife for all-solid-state rechargeable Li-I2 battery by a confined dissolutionstrategy.Nature Communications 2022,13(1).

[0133] 12.Peng L,Yu C,Zhang Z,Ren H,Zhang J,He Z,et al.Chlorine-rich lithiumargyrodite enabling solid-state batteries with capabilities ofhigh voltage,high rate,low-temperature and ultralong cyclability.ChemicalEngineeringJournal 2022,430.

[0134] 13.Ye L,Li X.A dynamic stability design strategy for lithium metalsolid state batteries.Nature 2021,593(7858):218.

[0135] 14. D. H. Kim et al., Infiltration of solution-processable solid electrolytes into conventional Li-ion-battery electrodes for all-solid-state Li-ion batteries. Nano letters 17, 3013-3020(2017).

[0136] Figure 11 C References:

[0137] 1. Xu R, Fudong Ji, Xiao Fan, Xiulin Tu, Jiangping Wang, Chunsheng. Interface engineering of sulfide electrolytes for all-solid-state lithium batteries. Nano Energy 2018, 53.

[0138] 2. Ji X, Hou S, Wang P, He X, Nan P, Chen J, et al. Solid-State Electrolyte Design for Lithium Dendrite Suppression. Advanced Materials 2020.

[0139] 3. Chen Y, Li W, Sun C, Jin J, Wang Q, Chen X, et al. Sustained Release-Driven Formation of Ultrastable SEI between Li6PS5Cl and Lithium Anode for Sulfide-Based Solid-State Batteries. Advanced Energy Materials 2021, 11(4).

[0140] 4.Cheng Z,Pan H,Li F,Duan C,Liu H,Zhong H,et al.Achieving long cyclelife for all-solid-state rechargeable Li-I2 battery by a confined dissolutionstrategy.Nature Communications 2022,13(1).

[0141] 5.Liang J,Li X,Zhao Y,Goncharova LV,Wang G,Adair KR,et al.In SituLi3PS4Solid-State Electrolyte Protection Layers for Superior Long-Life andHigh-Rate Lithium-Metal Anodes.AdvancedMaterials 2018,30(45).

[0142] 6.Kim C,Kim J,Park J,Kim J,Lee S,Sun S,et al.Ion-Conducting ChannelImplanted Anode Matrix for All-Solid-State Batteries with High RateCapability and Stable Anode / Solid Electrolyte Interface.AdvancedEnergyMaterials 2021,11(40).

[0143] 7.Lee K,Han S,Lee J,Lee S,Kim J,Ko Y,et al.Multifunctional Interfacefor High-Rate and Long-Durable Garnet-Type Solid Electrolyte in Lithium MetalBatteries.Acs Energy Letters 2022,7(1):381-389.

[0144] 8.Wan H,Zhang J,Xia J,Ji X,He X,Liu S,et al.F and N Rich SolidElectrolyte for Stable All-Solid-State Battery.AdvancedFunctionalMaterials2022,32(15).

[0145] 9.Zhou L,Zuo T-T,Kwok CY,Kim SY,Assoud A,Zhang Q,et al.High arealcapacity,long cycle life 4V ceramic all-solid-state Li-ion batteries enabledby chloride solid electrolytes.NatureEnergy 2022,7(1):83-93.

[0146] 10.Peng L,Yu C,Zhang Z,Ren H,Zhang J,He Z,et al.Chlorine-rich lithiumargyrodite enabling solid-state batteries with capabilities of high voltage,high rate,low-temperature and ultralong cyclability.ChemicalEngineeringJournal 2022,430.

[0147] 11.Tan DHS,Chen Y-T,Yang H,Bao W,Sreenarayanan B,Doux J-M,etal.Carbon-free high-loading silicon anodes enabled by sulfide solidelectrolytes.Science 2021,373(6562):1494.

[0148] 12. Lee Y-G, Fujiki S, Jung C, Suzuki N, Yashiro N, Omoda R, et al. High-energy long-cycling all-solid-state lithium metal batteries enabled by silver-carbon composite anodes. Nature Energy 2020, 5(4): 299-308.

[0149] 13. D.H. Kim et al., Infiltration of solution-processable solid electrolytes into conventional Li-ion-battery electrodes for all-solid-state Li-ion batteries. Nano letters 17, 3013-3020(2017). 14. Ye L, Li X. A dynamic stability design strategy for lithium metal solid state batteries. Nature 2021, 593(7858): 218.

[0150] Figure 12 fReferences:

[0151] 1. Xu R, Fudong Ji, Xiao Fan, Xiulin Tu, Jiangping Wang, Chunsheng. Interface engineering of sulfide electrolytes for all-solid-state lithium batteries. Nano Energy 2018, 53.

[0152] 2. Ji X, Hou S, Wang P, He X, Nan P, Chen J, et al. Solid-State Electrolyte Design for Lithium Dendrite Suppression. Advanced Materials 2020.

[0153] 3.Wan H,Zhang J,Xia J,Ji X,He X,Liu S,et al.F and N Rich SolidElectrolyte for Stable All-Solid-State Battery.AdvancedFunctionalMaterials2022,32(15).

[0154] 4.Kim C,Kim J,Park J,Kim J,Lee S,Sun S,et al.Ion-Conducting ChannelImplanted Anode Matrix for All-Solid-State Batteries with High RateCapability and Stable Anode / Solid Electrolyte Interface.AdvancedEnergyMaterials 2021,11(40).

[0155] 5.Chen Y,Li W,Sun C,Jin J,Wang Q,Chen X,et al.Sustained Release-Driven Formation of Ultrastable SEI between Li6PS5Cl and Lithium Anode forSulfide-Based Solid-State Batteries.AdvancedEnergy Materials 2021,11(4).

[0156] 6.Liang J,Li X,Zhao Y,Goncharova LV,Wang G,Adair KR,et al.In SituLi3PS4Solid-State Electrolyte Protection Layers for Superior Long-Life andHigh-Rate Lithium-Metal Anodes.AdvancedMaterials 2018,30(45).

[0157] 7.Lee Y-G,Fujiki S,Jung C,Suzuki N,Yashiro N,Omoda R,et al.High-energy long-cycling all-solid-state lithium metal batteries enabled bysilver-carbon composite anodes.NatureEnergy 2020,5(4):299-308.

[0158] 8.Tan DHS,Chen Y-T,Yang H,Bao W,Sreenarayanan B,Doux J-M,etal.Carbon-free high-loading silicon anodes enabled by sulfide solidelectrolytes.Science 2021,373(6562):1494.

[0159] 9.Lee K,Han S,Lee J,Lee S,Kim J,Ko Y,et al.Multifunctional Interfacefor High-Rate and Long-Durable Garnet-Type Solid Electrolyte in Lithium MetalBatteries.Acs Energy Letters 2022,7(1):381-389.

[0160] 10.Zhou L,Zuo T-T,Kwok CY,Kim SY,Assoud A,Zhang Q,et al.High arealcapacity,long cycle life 4V ceramic all-solid-state Li-ion batteries enabledby chloride solid electrolytes.NatureEnergy 2022,7(1):83-93.

Claims

1. A carbon-based interface layer, characterized in that, The interface layer includes a lithium-containing layer, and a carbon layer is disposed on the surface of the lithium-containing layer. The carbon layer includes soft carbon and doped nano-sized lithium lanthanum zirconium oxide particles, and the doped nano-sized lithium lanthanum zirconium oxide particles are uniformly dispersed in the soft carbon. The carbon layer also includes LiC6; The thickness of the carbon layer is 30μm-100μm; The doped nanoscale lithium lanthanum zirconium oxide particles have a D50 size of 280nm-320nm. The lithium-containing layer contains metallic lithium.

2. The carbon-based interface layer according to claim 1, characterized in that, The doped nanoscale lithium lanthanum zirconium oxide particles include Li 7-x B1 x La 3-y B2 y Zr 2-z B3 z O 12-u X u One type of particle, wherein B1 is at least one element selected from Ba, Al, Ga, Ge, Fe, B, Zn, and Ta; B2 is at least one element selected from Rb, Y, Bi, Pr, Nd, Pm, Sr, Ba, Ca, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, Ac, and Ta; B3 is at least one element selected from Mg, Sc, Ti, V, Cr, Mn, Ge, Se, Tc, Ru, Rh, Pd, Co, Ni, Cu, Cd, In, Sn, Sb, Te, I, Hf, Tl, Pb, Ce, Pu, Np, Ir, Pt, Y, Ta, Nb, Mo, and W; X is at least one element selected from F, Cl, Br, I, and S; 0 ≤ x < 0.8, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.8, and 0 ≤ u ≤ 0.1; at least one of x, y, z, and u is not 0.

3. The carbon-based interface layer according to claim 1, characterized in that, The thickness of the carbon layer is 30μm-50μm.

4. The carbon-based interface layer according to claim 1, characterized in that, The raw materials for the carbon layer include soft carbon and doped nano-sized lithium lanthanum zirconium oxide particles.

5. A carbon-based interface layer according to claim 4, characterized in that, By mass, the proportion of the doped nano-sized lithium lanthanum zirconium oxide particles in the total mass of soft carbon and the doped nano-sized lithium lanthanum zirconium oxide particles is greater than 0% and not higher than 30%.

6. A carbon-based interface layer according to claim 4, characterized in that, By mass, the doped nanoscale lithium lanthanum zirconium oxide particles account for 15%-25% of the total mass of soft carbon and the doped nanoscale lithium lanthanum zirconium oxide particles.

7. A carbon-based interface layer according to claim 2, characterized in that, The Li 7-x B1 x La 3-y B2 y Zr 2- z B3 z O 12-u X u Particles include Li 7-x B1 x La 3-y B2 y Zr 2-z B3 z O 12 One type of particle, wherein B1, B2, and B3 are all Ta; 0 ≤ x < 0.8, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.8; and at least one of x, y, and z is not 0.

8. A carbon-based interface layer according to claim 1, characterized in that, The soft carbon includes one or more of petroleum coke, needle coke, carbon fiber, coke, carbon microspheres, and graphite.

9. A carbon-based interface layer according to claim 1, characterized in that, The raw materials for the carbon layer also include a binder.

10. A carbon-based interface layer according to claim 9, characterized in that, The added mass of the binder is 4%-6% of the total mass of soft carbon and doped nano-sized lithium lanthanum zirconium oxide particles.

11. A carbon-based interface layer according to claim 9, characterized in that, The adhesive includes one or more of PTFE, polyvinylidene fluoride, styrene-butadiene rubber, alginate, polyacrylonitrile, and sodium carboxymethyl cellulose.

12. The method for preparing the interface layer according to any one of claims 1-11, characterized in that, The preparation method includes: weighing soft carbon and doped nano-sized lithium lanthanum zirconium oxide particles by mass, then adding a binder, hot pressing to obtain a precursor carbon layer, pressing the precursor carbon layer and the lithium-containing layer together, and then heat-preserving to obtain an interface layer. The hot pressing temperature is 60-80℃; the pressure per unit area during the hot pressing is 120MPa-150MPa. The preparation method also includes preparation in an argon atmosphere; The pressure per unit area of ​​the compression is 875MPa-1000MPa; The heat preservation treatment lasts for 10-14 hours and is performed at a temperature of 50-60°C.

13. A negative electrode, positive electrode, or separator comprising the interface layer according to any one of claims 1-11.

14. A battery comprising the negative electrode, positive electrode, or separator as described in claim 13.

15. The battery according to claim 14, characterized in that, The battery includes a liquid ion battery, a solid ion battery, or a polymer ion battery.

16. The battery according to claim 15, characterized in that, The solid-state ion battery includes a sulfide solid electrolyte battery, which further includes a positive electrode and a sulfide solid electrolyte.

17. The battery according to claim 16, characterized in that, The positive electrode includes a lithium cobalt oxide positive electrode active material coated with lithium zirconate; the sulfide solid electrolyte includes a Li6PS5Cl solid electrolyte.

18. The battery according to claim 17, characterized in that, The sulfide solid electrolyte battery has at least one characteristic: i achieves an ultra-long cycle life of 20,000 cycles at a high rate of 30C, and can provide 82.6mAh g after 20,000 cycles. -1 The specific capacity has a capacity retention rate of not less than 75%. ii at 12.5mA cm -2 It achieves a long cycle life of 4000 cycles at ultra-high current density, and can provide 90.1 mAh g after 4000 cycles. -1 The specific capacity has a capacity retention rate of not less than 95%. iii at 4.7mAh cm -2 At high capacity, it can be stably cycled 350 times at 1C with a capacity retention of no less than 90%; IV can achieve 15mAh cm -2 Ultra-high surface capacity; The discharge specific capacity at a 50C rate can reach 89.9 mAh g. -1 .

Images