Solid-state battery, battery device, power consuming device, and energy storage device

Abstract

This application relates to the field of interface engineering technology for all-solid-state lithium batteries, and particularly to solid-state batteries, battery devices, power consumption devices, and energy storage devices. Solid-state batteries include a positive electrode and a solid electrolyte in contact with the positive electrode. The positive electrode includes a positive electrode active material and an interface layer located on the positive electrode active material. The interface layer includes a transition layer and a polymer layer. The transition layer is located between the positive electrode active material and the polymer layer. The polymer layer includes polymer A and polymer B. Polymer A includes an A backbone and a Lewis acid grafted onto the A backbone. Polymer B includes a B backbone and a Lewis base grafted onto the B backbone. The Lewis acid and Lewis base constitute a frustrated Lewis pair. This application can solve the problem of HF, H2S, and SO2 generated by the coupling of oxygen release from the NCM positive electrode and the reduction and decomposition of sulfide solid electrolyte under high voltage. x Problems such as interface deterioration, transition metal dissolution, impedance increase, and rapid capacity decay caused by harmful substances.

Description

Technical Field

[0001] This application relates to the field of all-solid-state lithium battery interface engineering technology, and particularly to solid-state batteries, battery devices, power devices and energy storage devices. Background Technology

[0002] With the increasing demands for battery energy density in electric vehicles, high-nickel NCM cathodes have become the mainstream choice due to their high specific capacity. Meanwhile, sulfide solid electrolytes, with their high ionic conductivity and good mechanical properties, have become an important technological route for all-solid-state batteries. However, the interface between the NCM cathode and the sulfide solid electrolyte suffers from serious chemical and electrochemical instability. This manifests in two ways: under high voltage, structural phase transitions and oxygen release occur on the surface of the NCM cathode, while the sulfide electrolyte decomposes under oxidizing conditions. The coupling of these two processes generates a series of harmful substances, such as SO₂ produced by the reaction of oxygen with sulfides. x Residual moisture reacts with sulfides to produce H2S, and HF is produced under the catalysis of transition metals. These acidic and corrosive substances further exacerbate interfacial deterioration, leading to the dissolution of transition metals, a sharp increase in interfacial impedance, and rapid capacity decay. Summary of the Invention

[0003] Based on this, the first aspect of this application provides a solid-state battery, the technical solution of which is as follows:

[0004] A solid-state battery includes a positive electrode and a solid electrolyte in contact with the positive electrode. The positive electrode includes a positive electrode active material and an interface layer located on the positive electrode active material. The interface layer includes a transition layer and a polymer layer. The transition layer is located between the positive electrode active material and the polymer layer. The polymer layer includes polymer A and polymer B. Polymer A includes an A backbone and a Lewis acid grafted onto the A backbone. Polymer B includes a B backbone and a Lewis base grafted onto the B backbone. The Lewis acid and the Lewis base constitute a frustrated Lewis pair.

[0005] A second aspect of this application provides a battery device comprising a solid-state battery as described above, the battery device comprising one or more of a battery module, a battery pack, and an energy storage battery.

[0006] A third aspect of this application provides an electrical device comprising a battery device as described above, the battery device being used to provide electrical energy.

[0007] A fourth aspect of this application provides an energy storage device, the energy storage device including the battery device as described above, the battery device being used to store electrical energy.

[0008] Compared with traditional solutions, this application has the following advantages:

[0009] Frustrated Lewis pairs (FLPs) are an important concept in organocatalysis, referring to Lewis acids and Lewis bases that, due to steric hindrance, cannot form classic acid-base adducts but retain their individual reactivity. They can synergistically activate and capture small molecules such as H2 and CO2, exhibiting unique advantages in organocatalysis. This application attempts to apply FLPs to battery interfaces. First, a transition layer is used to provide anchoring sites for the polymer layer. Then, Lewis acids and Lewis bases are grafted onto the polymer to form FLPs, successfully achieving the activation and capture of HF, H2S, and SO2. x The selective capture of harmful substances at the interface can solve the interfacial stability problem when the NCM cathode comes into contact with the sulfide solid electrolyte, especially the HF, H2S, and SO2 generated by the coupling of oxygen release from the NCM cathode and the reduction decomposition of the sulfide solid electrolyte under high voltage. x Problems such as interface deterioration, transition metal dissolution, impedance increase, and rapid capacity decay caused by harmful substances.

[0010] The mechanism of action is as follows: HF is captured by Lewis bases to form ion pairs; H2S is fixed through Lewis acid addition and proton transfer; SO2 is... x It coordinates with Lewis acids. This synergistic capture mechanism breaks the chain decomposition pathway of acidic substances, achieving online purification of the interface.

[0011] This application enables the active chemical capture and online purification of various harmful substances generated in real time by interfacial reactions. It can selectively eliminate interfacial byproducts, inhibit the dissolution of transition metals, and maintain the long-term stability of the interface, providing a new interfacial solution for the practical application of high-energy-density all-solid-state batteries. Detailed Implementation

[0012] The present application will be further described in detail below with reference to specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0014] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0015] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more or more.

[0016] In this application, "several" means at least one, such as one, two, etc., unless otherwise expressly and specifically defined.

[0017] In this application, the terms "optionally," "optionally," and "optional" refer to options that are optional, meaning they can be selected from either "with" or "without." If multiple "optional" options appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" option is independent.

[0018] In this application, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

[0019] In this application, numerical intervals (i.e. numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the above-mentioned numerical intervals are considered continuous, and include the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical range, as well as every value between the two numerical endpoints.

[0020] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0021] The first aspect of this application discloses a solid-state battery. In one embodiment, the solid-state battery includes a positive electrode and a solid electrolyte in contact with the positive electrode. The positive electrode includes a positive electrode active material and an interface layer located on the positive electrode active material. The interface layer includes a transition layer and a polymer layer. The transition layer is located between the positive electrode active material and the polymer layer. The polymer layer includes polymer A and polymer B. Polymer A includes an A backbone and a Lewis acid grafted onto the A backbone. Polymer B includes a B backbone and a Lewis base grafted onto the B backbone. The Lewis acid and the Lewis base constitute a frustrated Lewis pair.

[0022] Frustrated Lewis pairs (FLPs) are an important concept in organocatalysis, referring to Lewis acids and bases that, due to steric hindrance, cannot form classic acid-base adducts but retain their individual reactivity. They can synergistically activate and capture small molecules such as H2 and CO2, exhibiting unique advantages in organocatalysis. This application attempts to apply FLPs to battery interfaces. First, a transition layer is used to provide anchoring sites for the polymer layer. Then, Lewis acids and bases are grafted onto the polymer to form FLPs, successfully achieving the activation and capture of HF, H2S, and SO2. x The selective capture of harmful substances at the interface can solve the interfacial stability problem when the NCM cathode comes into contact with the sulfide solid electrolyte, especially the HF, H2S, and SO2 generated by the coupling of oxygen release from the NCM cathode and the reduction decomposition of the sulfide solid electrolyte under high voltage. x Problems such as interface deterioration, transition metal dissolution, impedance increase, and rapid capacity decay caused by harmful substances.

[0023] The mechanism of action is as follows: HF is captured by Lewis bases to form ion pairs; H2S is fixed through Lewis acid addition and proton transfer; SO2 is... x It coordinates with Lewis acids. This synergistic capture mechanism breaks the chain decomposition pathway of acidic substances, achieving online purification of the interface.

[0024] The above-described embodiments innovatively introduce the FLP concept from the field of organic catalysis into solid-state battery interface engineering, realizing the Lewis acid / base synergistic capture function of small molecules. It can achieve active chemical capture and online purification of various harmful substances generated in real time by interface reactions, selectively eliminate interface by-products, inhibit the dissolution of transition metals, and maintain interface stability for a long time, providing a new interface solution for the practical application of high-energy-density all-solid-state batteries.

[0025] By employing polymer microphase separation technology, spatially separated but adjacent Lewis acid and Lewis base sites can be constructed on the same particle surface of the positive electrode active material, achieving a "frustrated" state and constructing an FLP functionalized nanobrush coating. Because the Lewis acid and base are spatially separated, they avoid self-neutralization, maintaining long-term activity.

[0026] In one embodiment, the Lewis acid comprises at least one of tris(pentafluorophenyl)borane (B(C6F5)3) and tris[3,5-bis(trifluoromethyl)phenyl]borane (B(3,5-(CF3)2C6H3)3). B(C6F5)3 and B(3,5-(CF3)2C6H3)3 have fluorine-rich groups, which can form a low surface energy outer layer, effectively suppressing electron leakage at high potentials and improving high voltage stability. B(3,5-(CF3)2C6H3)3 is less expensive and can partially replace B(C6F5)3, providing sufficient trapping sites without affecting energy density. The mass ratio of B(C6F5)3 to B(3,5-(CF3)2C6H3)3 is 1:(0~3).

[0027] When Lewis acids are grafted onto the A backbone of polymer A, they can be introduced in the form of diethyl ether complexes (e.g., B(C6F5)3·OEt2), improving storage stability. Subsequent decomposition under vacuum at 60–80°C for 20–40 minutes restores the activity of the Lewis acid. The decomposition temperature should not be too high to avoid thermal degradation or rearrangement of the polymer chain. The activity of the Lewis acid after decomposition can be confirmed by CO2 adsorption testing or XPS characterization. For example, the activity can be confirmed by detecting the characteristic CO2 adsorption peaks using infrared spectroscopy, or by detecting the shift of the B1s peak to a lower binding energy using XPS, indicating that decomposition is complete. B(3,5-(CF3)2C6H3)3, due to its mild acidity, can be used directly in its free state under an inert atmosphere, or as a weakly complexed form.

[0028] In one embodiment, the Lewis base includes at least one of cyclic guanidine bases and cyclic amidine bases; the cyclic guanidine base includes 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD); the cyclic amidine base includes 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0029] In one embodiment, the average spacing between the Lewis acid and the Lewis base is 2 nm to 8 nm. The average spacing can be characterized by the presence of characteristic scattering peaks in SAXS.

[0030] Polymer A is a Lewis acid-functionalized polymer. In one embodiment, the number-average molecular weight (Mn) of polymer A is 8 kDa to 25 kDa, and the polydispersity index (PDI) is ≤1.5; preferably ≤1.3. In one embodiment, the backbone of A is selected from poly(meth)acrylate segments or polynorbornene derivative segments. The polymerizing monomers include acrylate monomers and comonomers containing active side groups, wherein the acrylate monomers are selected from at least one of 2,2,2-trifluoroethyl methacrylate (TFEMA), 2,2,3,3,3-pentafluoropropyl methacrylate, and 2,2,3,3-tetrafluoropropyl methacrylate. The comonomers containing active side groups are selected from at least one of glycidyl methacrylate (GMA) and hydroxyethyl methacrylate (HEA). The active side groups are used for subsequent grafting of functional groups. It can be prepared by RAFT (reversible addition-fragmentation chain transfer) polymerization, which can precisely control the molecular weight and molecular weight distribution, ensuring batch-to-batch consistency. Polymer A is a low glass transition temperature polymer. Lewis acids can be grafted onto the A backbone via nucleophilic substitution or coupling reactions. The A backbone has a linking group formed by the connection of a nucleophilic group to an active side group. The nucleophilic group is the end-capping group of the Lewis acid, selected from at least one of primary amino (-NH2), hydroxyl (-OH), and thiol (-SH). The Lewis acid is grafted onto the A backbone through the connection of the nucleophilic group to the active side group. The end-capping group of polymer A includes an anchoring group, selected from phosphonic acid (-PO3H2), phosphonate ester, catechol, or hydroxamic acid; preferably phosphonic acid or catechol. The anchoring group can form a stable coordination bond with the metal-oxygen bond on the LiNbO3 surface. The anchoring group can be introduced via transesterification or amidation reactions.

[0031] In one embodiment, an average of 3 to 8 Lewis acids are grafted onto each main chain of polymer A, with adjacent Lewis acids separated by C6 to C10 segments.

[0032] Polymer B is a Lewis base-functionalized polymer. In one embodiment, the number-average molecular weight (Mn) of polymer B is 8 kDa to 20 kDa, and the polydispersity index (PDI) is ≤1.5; preferably ≤1.3. In one embodiment, the backbone of B is selected from poly(meth)acrylate segments or polynorbornene derivative segments. The polymerizing monomers include acrylate monomers and comonomers containing active side groups, wherein the acrylate monomers are selected from at least one of 2,2,2-trifluoroethyl methacrylate (TFEMA), 2,2,3,3,3-pentafluoropropyl methacrylate, and 2,2,3,3-tetrafluoropropyl methacrylate. The comonomer containing active side groups is selected from N-hydroxysuccinimide acrylate (NAS). The active side groups are used for subsequent grafting of functional groups. It can be prepared by RAFT (reversible addition-fragmentation chain transfer) polymerization, which can precisely control the molecular weight and molecular weight distribution, ensuring batch-to-batch consistency. Polymer B is a low glass transition temperature polymer. The B backbone has linking groups, including at least one urea group and an amide group; the Lewis base is grafted onto the B backbone through these linking groups. This linking mechanism achieves a "weakly locked" Lewis base, maintaining its basic activity while inhibiting transdomain neutralization with Lewis acids. The Lewis base can be grafted onto the B backbone via Michael addition or amidation reactions. The end-capping groups of the polymer B include anchoring groups, selected from phosphonic acids (-PO3H2), phosphonate esters, catechols, or hydroxamic acids; preferably phosphonic acids or catechols. The anchoring groups can form stable coordination bonds with the metal-oxygen bonds on the LiNbO3 surface. The anchoring groups can be introduced via transesterification or amidation reactions.

[0033] In one embodiment, an average of 2 to 5 Lewis bases are grafted onto each B main chain of the polymer B, with adjacent Lewis bases spaced apart by C6 to C10 segments.

[0034] In this embodiment, the method for determining the average number of Lewis acids grafted onto each A main chain and the average number of Lewis bases grafted onto each B main chain is as follows: the molecular weight Mn and polydispersity index PDI are confirmed by GPC, and then combined with... 1 H NMR and 19 F NMR quantifies the integral ratio of functional groups to main-chain repeating units. For example, 19 In F NMR, the ortho / para / meta fluorine of B(C6F5)3 exhibits three sets of characteristic peaks in the -130 to -165 ppm range. The integral area of ​​these peaks, compared to the integral ratio of the repeating unit in the A main chain, combined with the known Mn, allows for the calculation of the average number of Lewis acid grafts per chain. Similarly, 1The characteristic methylene signal (δ 2.8-3.5 ppm) on the TBD ring in 1H NMR can be used to quantify the average number of Lewis base grafts per chain by integration. 19 F NMR quantification of F content can be used to estimate the total amount of Lewis acids. Elemental analysis determines the B and N contents, corresponding to the total amounts of Lewis acids and Lewis bases, respectively. The length of the spacer segment between adjacent functional groups can be determined during the monomer design stage; for example, a C6-C10 methylene spacer arm can be pre-defined in the molecular structure of the functionalized monomer. 1 The presence of methylene signals in the δ 1.2–1.6 ppm range in ¹H NMR verifies that the interval length is consistent with the design.

[0035] In one embodiment, the molar ratio of polymer A to polymer B is (6~8):(2~4), preferably 7:3.

[0036] In one embodiment, the method for preparing the polymer layer includes the following steps: mixing polymer A, polymer B, and a solvent to obtain a coating solution; spray-depositing the coating solution and then drying it. The above method is feasible and cost-effective.

[0037] The solvent is selected from fluorinated inert solvents, such as HFE-7300, to ensure compatibility with the sulfide electrolyte. The coating solution must be freshly prepared before use to avoid phase separation or aggregation caused by prolonged storage. Dynamic light scattering (DLS) can be used to confirm the absence of aggregates in the coating solution. The cathode particles can be kept in motion in a vibrating or fluidized bed to ensure uniform coating. The coating solution is deposited by ultrasonic spraying or pneumatic spraying. Spraying is performed in an inert atmosphere or dry air. Spraying parameters include: atomization pressure 0.1~0.3MPa, liquid flow rate 0.5~2mL / min, and nozzle distance 10~20cm. The temperature of the deposition substrate is 25~40℃. During drying, the solvent evaporates and promotes phase separation. The Flory-Huggins interaction parameter χ>0 between the A and B main chains assembles into a nanobrush layer on the particle surface, and a phase-separated structure spontaneously forms within the nanobrush layer. The phase separation process can be controlled by adjusting the drying temperature and time to achieve a "frustrated" state, thus constructing the FLP functionalized nanobrush coating.

[0038] In one embodiment, the polymer layer further includes polymer C. This polymer acts as a fluorine-rich inert diluent, promoting phase separation and controlling the size of nanodomains. Polymer C comprises perfluoroalkyl methacrylate segments. The monomer comprises 1H,1H,2H,2H-perfluorooctyl methacrylate. Its high fluorine content provides a stronger driving force for phase separation. The number-average molecular weight of polymer C is 8 kDa to 15 kDa. Polymer C accounts for 0 to 20 mol% of the total polymer moles; preferably 10 to 20 mol%. The total polymer moles are the sum of the moles of polymers A, B, and C. Polymer C promotes phase separation and controls the size of nanodomains. Polymer C is a fluorine-rich inert polymer without functional groups.

[0039] In one embodiment, the thickness of the polymer layer is 8 nm to 20 nm, preferably 10 nm to 15 nm. The weight of the polymer layer accounts for 0.25 wt% to 0.5 wt% of the weight of the positive electrode active material. The weight gain does not exceed 0.5 wt%. The ultra-thin polymer layer thickness and small weight gain provide sufficient chemical processing capability while maintaining ion transport.

[0040] In one embodiment, the transition layer comprises LiNbO3. The thickness of the transition layer is 2 nm to 5 nm, preferably 3 ± 1 nm. The transition layer can be prepared by atomic layer deposition (ALD) or sol-gel method, mainly serving as an electron barrier and structural buffer. Simultaneously, the -OH and MO- groups on its surface provide anchoring sites for the polymer chain nanobrush. During the spraying process, the anchoring groups can coordinate with the LiNbO3 surface to form a stable chemical anchor. The thickness and morphology of the transition layer can be confirmed by cross-sectional observation using transmission electron microscopy (TEM), and the crystallinity can be characterized by X-ray diffraction (XRD).

[0041] In one embodiment, the preparation of LiNbO3 by ALD includes the following steps: LiOtBu and Nb(OEt)5 precursors are alternately introduced at a reaction temperature of 150–200°C, with approximately 0.1 nm deposited per cycle, and this process is repeated for 30–50 cycles to obtain a LiNbO3 layer with a thickness of 2–5 nm. Subsequently, the layer is annealed at 250–300°C in an oxygen atmosphere for 30 minutes to improve crystallinity and density.

[0042] In one embodiment, the preparation of LiNbO3 by the sol-gel method includes the following steps: dissolving LiOEt and Nb(OEt)5 in anhydrous ethanol at a 1:1 molar ratio, with a concentration of 0.1M. NCM powder is impregnated-coated or spray-coated in the sol, controlling the coating amount to achieve a final thickness of 2nm~6nm. Heat treatment is then performed at 250~300℃ for 1 hour under nitrogen protection to form a LiNbO3 coating.

[0043] In one embodiment, the positive electrode active material includes at least one of NCM811, NCM622, NCM9055, and NCA. NCM811 is a high-nickel layered oxide LiNi. 0.8 Co 0.1 Mn 0.1 O2 positive electrode active material. NCM622 is LiNi 0.6 Co 0.2 Mn 0.2 The secondary particle size D50 of the positive electrode active material described in O2 is 5~12μm. The thickness of the positive electrode is 50~100μm. The positive electrode can be formed by compression molding. During compression, the pressure is controlled at 300~500MPa to ensure that the nanobrush layer of the polymer layer on the positive electrode active material remains intact and does not fall off or transfer to the electrolyte particles.

[0044] In one embodiment, the solid electrolyte comprises a sulfide solid electrolyte. The sulfide solid electrolyte includes Li6PS5Cl, Li6PS5Br, Li6PS5I, and Li7P3S. 11 and L 10 GeP2S 12 At least one of the following. The solid electrolyte has a particle size D50 of 1~5μm, a water oxygen content ≤50ppm, and an ionic conductivity of not less than 2×10⁻⁶. -3 S / cm (25℃).

[0045] The aforementioned solid-state battery can construct an FLP-functionalized nanobrush coating on the positive electrode active material, especially the high-nickel layered oxide positive electrode active material, to achieve in-situ capture and online purification of interfacial reaction products. This aims to selectively eliminate interfacial byproducts, inhibit transition metal dissolution, and maintain long-term interfacial stability. It addresses the interfacial stability issue when high-nickel layered oxide positive electrode active materials contact sulfide solid electrolytes, particularly the HF, H2S, and SO2 generated by the coupling of oxygen release from the positive electrode and electrolyte reductive decomposition under high voltage. x Problems such as interface deterioration, transition metal dissolution, and impedance growth caused by harmful substances provide new interface solutions for the practical application of high-energy-density all-solid-state batteries.

[0046] In one embodiment, the solid-state battery further includes a negative electrode, which is in contact with the solid electrolyte and separated from the positive electrode by the solid electrolyte. The negative electrode includes a lithium metal negative electrode or a lithium alloy negative electrode. For example, a Li-In alloy, which has an electrochemical potential of approximately 0.62 V vs Li / Li+, exhibits better interfacial stability and experimental repeatability compared to a lithium metal negative electrode, making it suitable as a standardized testing platform for evaluating the interface modification effect on the positive electrode side. Alternatively, other lithium alloys can also be used for the negative electrode.

[0047] This embodiment of the all-solid-state lithium battery involves the interfacial modification of a high-nickel layered oxide (NCM) cathode and a sulfide solid electrolyte. It innovatively introduces the FLP (Fluid-Liquid Processing) concept from the field of organic catalysis into solid-state battery interface engineering, forming a unique interfacial layer. Based on the active capture and online purification technology of FLP chemistry, an FLP-functionalized nanobrush coating is constructed on the surface of the NCM cathode particles to achieve the Lewis acid / base synergistic capture of small molecules, enabling in-situ capture and online purification of interfacial reaction products.

[0048] Traditional interface modification strategies mainly include inorganic oxide coating isolation, conductive polymer coating, porous material adsorption, addition of chemical additives, and surface chemical modification. Inorganic oxide coatings are formed on the surface of NCM particles using atomic layer deposition (ALD), sol-gel methods, or wet chemical methods to create nanoscale oxide layers, such as LiNbO3 or Al2O3 layers. LiNbO3 layers are widely studied due to their high ionic conductivity and chemical stability, and are typically 3–10 nm thick. The main mechanism of action of inorganic oxide coatings is physical barrier, reducing direct contact between NCM and the electrolyte, thus blocking electron transport to some extent, reducing electron leakage, and lowering the rate of side reactions. However, inorganic oxide coatings lack the ability to handle harmful substances already generated at the interface, such as generated gas molecules and soluble substances, and can only passively slow down the rate of side reactions. Conductive polymer coatings stabilize the interface by improving interfacial wettability and mechanical compatibility. Conductive polymers such as PEDOT and polyaniline can provide electron transport channels while buffering volume changes. Ion-conducting polymers such as PEO and PVDF can promote lithium-ion transport. However, polymer materials exhibit limited stability under high voltage and also lack the ability to chemically treat harmful substances already formed at the interface. Porous materials such as MOFs and mesoporous carbon can adsorb harmful substances after being introduced into the interface. These materials possess high specific surface areas (>1000 m²). 2 Porous adsorbent materials (NCMs) with adjustable pore sizes can physically adsorb a certain amount of molecules such as H2S and HF. However, these materials rely primarily on physical adsorption, which suffers from poor selectivity, easy saturation, and high-temperature desorption, making it impossible to selectively and continuously treat harmful interfacial substances. Furthermore, high loading of porous adsorbent materials significantly increases interfacial resistance, affecting battery performance. Adding chemical additives involves adding alkaline substances such as Li3PO4 and Li2CO3 to the cathode or electrolyte to neutralize acidic products. This method can consume acidic substances like HF to some extent, but the additives are unevenly distributed, and reaction products may block ion transport channels. In addition, excessive additive dosage can affect the electrode's energy density. Surface chemical modification alters interfacial properties by grafting functional groups onto the NCM surface. For example, hydrophobic groups are introduced through silane coupling agents to reduce water adsorption, or complexing groups are introduced to capture transition metal ions. However, such modifications typically address only a single problem and cannot simultaneously solve multiple interfacial issues.

[0049] In summary, traditional interface modification strategies suffer from the following problems: First, the capture mechanisms are singular and inefficient. Both physical adsorption and chemical neutralization lack selectivity and controllability. Physical adsorption relies on specific surface area and pore size, exhibiting little difference in adsorption capacity for different molecules, and is easily occupied by impurities such as moisture. While chemical neutralization can consume some acidic substances, the reaction is irreversible, and product accumulation deteriorates the interface. There is a lack of a mechanism capable of selectively, reversibly, or regenerably treating multiple harmful substances. Second, their limited functionality makes them ill-suited for complex interface environments. For example, the NCM / sulfide interface simultaneously contains HF, H2S, and SO2. x And many other harmful substances, as well as Ni 2+ Mn 2+ Co 2+ Ion dissolution. Traditional interface modification strategies often only address one type of problem, making comprehensive treatment difficult. Even combining multiple technologies can lead to complex interface structures, increased costs, and mutual interference. Furthermore, most coating technologies are passive, only slowing down side reaction rates but not eliminating existing harmful substances. As the cycle continues, harmful substances accumulate at the interface, eventually leading to failure. An active, dynamic treatment mechanism is needed to capture and transform harmful substances simultaneously with their formation.

[0050] Furthermore, traditional interface modification strategies suffer from the following problems: First, to provide sufficient protection or adsorption capacity, coating thicknesses often need to reach tens of nanometers or even micrometers, which significantly increases interfacial resistance and reduces rate performance. While ultrathin coatings (<5nm) have little impact on ion transport, their functionality is limited. There is a lack of technical solutions to achieve high-efficiency functionality at the nanoscale. Second, many organic coatings or adsorbents decompose, desorb, or deactivate at battery operating temperatures (especially >45°C). Physically adsorbed molecules are prone to desorption and re-release at high temperatures. Chemically bonded groups may participate in side reactions. Stable interfacial functionality needs to be maintained over a wide temperature range. Third, many interface modifications require the use of polar solvents, which is fatal to moisture-sensitive sulfide electrolytes. Even with non-polar solvents, residual active groups may react with sulfides. There is a lack of interface technologies specifically designed for sulfide systems.

[0051] Unlike traditional interface modification strategies, the interface strategy in solid-state batteries provided by the above embodiments has the following advantages:

[0052] 1. Selective chemical capture vs. nonspecific physical adsorption

[0053] Traditional porous materials such as MOFs and activated carbon mainly rely on physical adsorption, exhibiting little difference in adsorption capacity for different molecules, easily becoming saturated, and are non-renewable. The FLP sites in this embodiment utilize a Lewis acid-base synergistic mechanism to adsorb HF, H2S, and SO2. x Small molecules containing lone pair electrons or protons possess specific recognition and chemical binding capabilities. Among them, B(C6F5)3 selectively captures F... - By forming stable BF bonds, TBD selectively accepts protons, and the two work together to form ion pairs, achieving chemical selective capture rather than simple physical adsorption.

[0054] 2. Spatial Frustration Design vs. Acid-Base Self-Nutrition

[0055] Simply mixing Lewis acids and Lewis bases will immediately result in a neutralization reaction and loss of activity. This embodiment utilizes polymer phase separation technology to immobilize Lewis acids and bases onto different polymer backbones, forming phase-separated nanodomains on an 8-20 nm scale by leveraging thermodynamic incompatibility. The average spacing between the Lewis acid and base is maintained at 2-8 nm, which is close enough to synergistically capture small molecules while avoiding self-neutralization caused by direct contact, achieving a truly "frustrated" state.

[0056] 3. Online dynamic purification vs. pre-emptive static protection

[0057] Traditional technologies such as inorganic coatings are static protective layers that can only passively mitigate side reactions and are powerless against already generated harmful substances. This implementation method achieves dynamic purification during operation: when interfacial reactions produce substances such as HF and H2S, the FLP sites immediately capture and transform them, preventing further harm from these substances. This "processing while generating" online purification mechanism fundamentally changes the interfacial protection strategy.

[0058] 4. Burden of ultra-thin functional layers vs. thick coatings

[0059] To provide sufficient adsorption capacity, traditional porous coatings often require micrometer-level thicknesses, severely impacting ion transport. In this embodiment, the polymer layer thickness is only 8–20 nm, with a total weight gain of 0.25–0.40 wt%, having a negligible impact on ion transport. Through precise molecular design, high-density functional sites (up to 10^6) are achieved at the nanoscale. 13 ~10 14 pcs / cm 2 It provides sufficient chemical processing capabilities with minimal material usage.

[0060] 5. Synergistic effect of fluorine-rich surfaces vs. single function

[0061] The pentafluorophenyl group of B(C6F5)3 not only provides Lewis acidity, but its fluorine-rich properties also form a low surface energy layer on the nanobrush surface. This fluorine-rich surface reduces electron affinity, effectively suppressing electron leakage from the NCM to the electrolyte at high potentials and reducing redox side reactions. This synergistic effect of chemical trapping and electron blocking is something that traditional monofunctional coatings cannot achieve.

[0062] 6. Interdisciplinary conceptual innovation vs. incremental improvement

[0063] This implementation method introduces the concept of FLP (Fluid Propulsion) from the field of organic catalysis into battery interface engineering for the first time, achieving interdisciplinary innovation. The unique advantages of FLP in small molecule activation are creatively applied to the treatment of harmful substances at the battery interface, opening up a new direction for interface engineering. This conceptual innovation differs from traditional incremental improvements.

[0064] 7. Programmable design vs. trial and error

[0065] By adjusting parameters such as the A:B chain ratio, phase separation scale, and spacer length, the density, distribution, and activity of FLP sites can be precisely controlled. This molecular design-based "programmable" interface engineering method offers greater predictability and optimizability compared to traditional empirical trial-and-error methods. Interface layer structures can be customized to suit different cathode materials and electrolyte systems.

[0066] The aforementioned solid-state batteries have high capacity characteristics and can be used in battery devices, and further in electrical devices or energy storage devices.

[0067] A second aspect of this application provides a battery device. In one embodiment, the battery device includes a solid-state battery as described above, and the battery device includes one or more of a battery module, a battery pack, and an energy storage battery. The battery device disclosed in the embodiments of this application can be used, but is not limited to, in electrical devices or energy storage devices such as vehicles, ships, or aircraft.

[0068] A third aspect of this application provides an electrical device. In one embodiment, the electrical device includes a battery device as described above, the battery device being used to provide electrical energy. The electrical device can be, but is not limited to, a mobile phone, tablet, laptop, electric toy, power tool, electric vehicle, electric car, ship, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.

[0069] This application provides a fourth aspect of an energy storage device. In one embodiment, the energy storage device includes a battery device as described above, the battery device being used to store electrical energy. The energy storage device can be, but is not limited to, an energy storage container, an energy storage cabinet, an energy storage power station, an energy storage battery pack, or a portable energy storage system. The above-mentioned energy storage device possesses excellent long-term energy storage capabilities. It can support continuous operation for 4 hours or 8 hours, effectively coping with long-term, high-load power consumption scenarios, achieving stable and reliable long-term energy storage support, and providing users with lasting power security.

[0070] The following description is further illustrated with specific embodiments and comparative examples. Unless otherwise specified, the raw materials involved in the following specific embodiments and comparative examples are all commercially available. Unless otherwise specified, the instruments used are all commercially available. Unless otherwise specified, the processes involved are conventionally selected by those skilled in the art.

[0071] The positive electrode active material uses NCM811 and NCM622, with a secondary particle size D50 of 8±1μm and a purity of not less than 99.5%. The sulfide solid electrolyte uses Li6PS5Cl and Li6PS5Br, with a D50 of 2±0.5μm, a water oxygen content ≤50ppm, and an ionic conductivity of not less than 2×10⁻⁶. -3 S / cm (25℃). The negative electrode uniformly uses a Li-In alloy (Li:In molar ratio = 0.5:1), with a thickness of approximately 100 μm. The transition layer is prepared using transition precursors, namely LiOtBu, LiOEt, and Nb(OEt)5. LiOtBu and Nb(OEt)5 are used for the ALD method to prepare LiNbO3, while LiOEt and Nb(OEt)5 are used for the sol-gel method. The thickness of LiNbO3 prepared by the ALD method is 3 ± 1 nm, and the thickness of LiNbO3 prepared by the sol-gel method is 5 ± 1 nm. The coating solvent for the polymer layer is HFE-7300 fluorinated inert solvent. The conductive carbon is Super P (conductive carbon black), and the binder is polytetrafluoroethylene (PTFE). The MOF adsorbent used in comparative example CE7 is ZIF-8 (2-methylimidazolium zinc salt), with a specific surface area of ​​not less than 1200 m². 2 / g, with a particle size of approximately 100nm.

[0072] The polymer preparation materials included: RAFT chain transfer agent (CTA), initiator azobisisobutyronitrile (AIBN), the main fluorinated monomer 2,2,2-trifluoroethyl methacrylate (TFEMA), comonomer glycidyl methacrylate (GMA), and N-hydroxysuccinimide acrylate (NAS). Lewis acids were B(C6F5)3·OEt2 and B(3,5-(CF3)2C6H3)3. Lewis bases were amino-modified TBD and amino-modified DBU. Phosphonic acid functionalizing agents were maleimide reagents containing phosphonic acids and C-class dilution chain monomers 1H,1H,2H,2H-perfluorooctyl methacrylate. All polymers were synthesized in anhydrous THF or DMF. After purification, molecular weight and polydispersity index were confirmed by gel permeation chromatography (GPC), and the number of functional groups grafted and the degree of functionalization were confirmed by nuclear magnetic resonance spectroscopy (1H NMR and 19F NMR).

[0073] All the chemical reagents mentioned above are analytical grade or battery-grade materials, and are commercially available. All operations involving water- and oxygen-sensitive materials were performed in an argon-atmospheric glove box, where the water and oxygen content was controlled to be below 1 ppm.

[0074] Example E1

[0075] This embodiment provides a solid-state battery and its preparation method. Referring to Table 1, the steps are as follows:

[0076] Step 1: NCM pretreatment and inorganic transition layer deposition

[0077] The NCM811 secondary particles were first dried under vacuum at 120°C for 4 hours to remove surface adsorbed moisture, leaving a residual moisture content ≤50ppm. The transition precursors LiOtBu and Nb(OEt)5 were alternately introduced at 150–200°C, with approximately 0.1 nm deposited per cycle. This process was repeated for 30 cycles to obtain a LiNbO3 layer with a thickness of 3±1 nm as the transition layer. Subsequently, the layer was annealed at 250°C in an oxygen atmosphere for 30 minutes.

[0078] Step 2, Polymer Preparation

[0079] Preparation of Polymer A: Step 1: TFEMA and GMA were RAFT copolymerized in anhydrous THF at a predetermined ratio, using AIBN as the initiator. The amount of chain transfer agent was calculated based on a target number-average molecular weight (Mn) of approximately 15 kDa. The reaction was carried out at 70°C under nitrogen protection for 12 hours. The product was purified by precipitating in n-hexane and then vacuum dried. Step 2: The copolymer was dissolved in anhydrous toluene in a glove box. B(C6F5)3·OEt2, with primary amino-substituted end groups, was added as a functionalizing agent. The mixture was stirred at room temperature for 12 hours. The primary amino groups underwent nucleophilic ring-opening reactions on the GMA side-chain epoxy groups, forming β-hydroxy secondary amino groups as linking groups. An average of 3 to 8 Lewis acid groups were grafted onto each chain. The Lewis acid-containing structural units were linked to the polymer backbone through the active sites of the GMA epoxy groups on the side chains. B(C6F5)3, under the coordination protection of diethyl ether, maintained a tricoordinate sp... 2 Configuration and Lewis acid activity state. In the third step, the dithioester group at the end of the RAFT chain transfer agent is exposed to the thiol terminus via aminolysis, and then Michael addition is performed with a phosphonic acid-containing maleimide reagent to introduce an anchoring group.

[0080] The preparation of polymer B is similar to that of polymer A, with the main difference being: First, a polymethacrylate containing NAS active ester side groups is prepared, with Mn approximately 12 kDa. Second, amino-modified TBD is added to anhydrous DMF and stirred at 50°C for 12 hours. The NAS ester groups react with the primary amino groups of TBD to form amide bonds, each bond branching 2 to 5 Lewis base groups. The guanidino nitrogen atom of TBD retains its unbonded lone pair electrons, maintaining Lewis base activity.

[0081] Polymer C is a homopolymer of 1H,1H,2H,2H-perfluorooctyl methacrylate with Mn=8~12kDa. It does not contain functional groups and provides phase separation regulation.

[0082] Polymers A, B, and C were purified three times by precipitation, vacuum dried, and stored under an inert atmosphere. Before use, their molecular weight and polydispersity index were confirmed by GPC (THF mobile phase, polystyrene standard). Polymers A and B were purified by... 1 H NMR and 19 F NMR (CDCl3 or d8-THF solvent, 400 MHz) confirmed the average number of Lewis acid grafts per A backbone and the average number of Lewis base grafts per B backbone.

[0083] Step 3: Coating, phase separation induction, and Lewis acid activation to prepare the polymer layer.

[0084] In an argon-filled glove box (H₂O < 1 ppm, O₂ < 1 ppm), polymers A, B, and C were dissolved in HFE-7300 fluorinated solvent. The molar ratio of polymer A to B was 7:3, and polymer C comprised 15 mol% of the total moles. The total polymer concentration was 10 mg / mL, equivalent to approximately 1 wt% solids. The resulting solution was filtered through a 0.2 μm PTFE membrane to remove particulate impurities, yielding the coating solution. Dynamic light scattering (DLS) confirmed the absence of aggregates in the coating solution.

[0085] An ultrasonic spraying system was used to uniformly deposit a coating solution onto the surface of NCM811 particles with LiNbO3 deposited on their surface. Spraying was conducted in an inert atmosphere (dew point < -40℃), with an atomization pressure of 0.2 MPa, a liquid flow rate of 1 mL / min, and a nozzle distance of 15 cm. The NCM811 particles with LiNbO3 deposited on their surface were kept in motion in a vibrating bed to ensure uniform coating, at a temperature of 40℃. By controlling the spraying time and weighing using a precision balance, the total weight gain was achieved to 0.30 wt%. The coated powder was treated in a vacuum oven at 80°C for 30 minutes to remove residual solvent and promote microphase separation based on thermodynamic incompatibility between the A backbone (fluorine-rich hydrophobic) and the B backbone (nitrogen-containing weakly polar). (The Flory-Huggins interaction parameter χ>0 between the A and B backbones leads to spontaneous microphase separation in the nanofilm). The powder was then left to stand at room temperature for at least 2 hours to further optimize the phase separation structure. Subsequently, the powder was treated under vacuum at 60–80°C for 30 minutes to complete the decomplexing activation of B(C6F5)3·OEt2 and restore its tricoordinate Lewis acidity. The degree of decomplexing was confirmed by surface analysis methods such as XPS. The samples were immediately transferred to an inert atmosphere for storage after decomplexing. The thickness of the polymer layer was observed using TEM cross-section, and the results are shown in Table 1. Phase-separated nanodomains at the 8–20 nm scale were observed using atomic force microscopy (AFM) phase mode imaging.

[0086] Step 4: Assemble the composite cathode and battery.

[0087] NCM material (including transition and polymer layers), Li6PS5Cl, Super P conductive carbon, and PTFE binder were dry-mixed in an agate mortar within a glove box at a mass ratio of 60:35:3:2. The mixed powder was cold-pressed (400 MPa) to obtain a positive electrode composite sheet with a thickness of approximately 80 μm. The battery assembly adopted a structure of NCM positive electrode (including transition and polymer layers) | sulfide solid electrolyte layer (approximately 600 μm) | Li-In alloy negative electrode, with an assembly pressure of 10 MPa.

[0088] Comparative Examples CE1-CE7, Examples E2-E13

[0089] The above comparative examples and embodiments provide a solid-state battery and its preparation method, which are basically the same as those in Example 1. The main differences are shown in Table 1.

[0090] In the preparation method of CE5, B(C6F5)3·OEt2 and amino-modified TBD are grafted onto the same polymer chain, and the rest of the process is the same. CE7 uses ZIF-8 instead of the polymer layer: ZIF-8 nanoparticles are ultrasonically dispersed in anhydrous ethanol, spray-deposited onto the surface of NCM811 particles with LiNbO3 deposited on the surface, with a weight gain of about 0.35wt%, and vacuum dried at 60℃.

[0091] E6 Replace B(C6F5)3·OEt2 with a mixture of B(C6F5)3·OEt2 and B(3,5-(CF3)2C6H3)3 in a 1:1 mass ratio; E7 Replace amino-modified TBD with amino-modified DBU; E8 No polymer C was added; E9 The amount of polymer C used was 20 mol%; E10 Replace the maleimide reagent containing phosphonic acid with a catechol functionalizing reagent; E11 Replace NCM811 with NCM622; E12 Replace Li6PS5Cl with Li6PS5Br; E13 Step 1 is: NCM811 secondary particles are first dried at 120℃ under vacuum for 4 hours to remove surface adsorbed moisture, so that the residual moisture is ≤50ppm. LiOEt and Nb(OEt)5 were dissolved in anhydrous ethanol (0.1M) at a 1:1 molar ratio. NCM811 was spray-coated in the sol and heat-treated at 250°C under nitrogen protection for 1 hour to obtain a LiNbO3 layer with a thickness of 5±1 nm as a transition layer.

[0092] Table 1

[0093]

[0094] Performance testing methods

[0095] Since the electrochemical potential of the Li-In alloy anode is approximately 0.62 V vs Li / Li+, all charge and discharge voltage windows in the test are marked with Li / Li+ as the reference: upper limit of charging 4.3V, lower limit of discharging 2.8V, corresponding to a measured voltage window of approximately 2.18 to 3.68V for the Li-In anode.

[0096] Each example and comparative example had 3 to 5 parallel cells prepared independently, and all performance data were averaged, with a typical error range of ±5% to 10%. All electrochemical tests used the same batch of electrolyte powder and negative electrode material to eliminate the influence of batch differences.

[0097] Interfacial impedance was determined by electrochemical impedance spectroscopy (EIS). A small AC signal with a frequency range of 0.1 Hz to 1 MHz and an amplitude of 10 mV was applied to the assembled full cell at 25 °C, and measurements were taken before cycling and after 200 cycles at 1 C. The charge transfer resistance Rct (in Ω cm⁻¹) was extracted by equivalent circuit fitting. 2 This parameter directly reflects the ion transport resistance and interface degradation degree at the cathode / solid electrolyte interface.

[0098] Capacity retention rate was determined during cycling at 25℃. The charging regime was 1C constant current charging to the upper limit voltage of 4.3V (vs Li / Li+, the same below), followed by constant voltage charging to the cutoff current of 0.05C. The discharging regime was 1C constant current discharging to the lower limit voltage of 2.8V. Cycling was performed continuously for 500 cycles, and the discharge capacity was recorded on the 200th and 500th cycles. Capacity retention rate (%) = (discharge capacity on the nth cycle / discharge capacity on the first cycle) × 100%. Cyclic capacity retention rate is a core indicator for measuring the long-term stability of the interface, directly reflecting the continuous suppression effect of the FLP online purification mechanism on interfacial side reactions.

[0099] Capacity retention rate determination at 45℃. The same charge-discharge regime as at 25℃ was used, and the test was conducted at a constant temperature of 45℃. Capacity retention rates were recorded at the 100th and 200th cycles. Under high-temperature conditions, the formation rates of harmful species such as HF and H2S are significantly accelerated. This test can distinguish the performance differences between active chemical capture mechanisms and passive physical barrier mechanisms under extreme conditions.

[0100] The first-cycle coulombic efficiency (ICE) was measured at 25°C under the same charge / discharge regime as above. ICE(%) = (first-cycle discharge capacity / first-cycle charge capacity) × 100%. The first-cycle coulombic efficiency reflects the degree of irreversible side reactions at the interface during the first charge and discharge process, and can indirectly evaluate the ability of the interface layer to suppress initial side reactions.

[0101] Rate performance was measured at 25°C. Charging was performed using a constant current of 0.2C to 4.3V, followed by constant voltage charging to 0.05C cutoff. Discharging was conducted at three rates: 0.2C, 1C, and 3C, with three cycles per rate, and the discharge capacity on the third cycle was recorded. Using the 0.2C discharge capacity as a baseline (100%), the capacity retention ratio (%) at 3C discharge was calculated as (3C discharge capacity / 0.2C discharge capacity) × 100%. Rate performance reflects the influence of the interface layer on ion transport and is used to verify whether the polymer thickness window (8 to 20 nm) introduces excessive interfacial polarization.

[0102] Transition metal dissolution was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). After cycling 200 times at 25°C, the battery was disassembled in a glove box, the solid electrolyte layer was removed, dissolved in 2% dilute nitric acid, and brought to volume. The contents (ppm) of Ni, Co, and Mn were then determined. Transition metal dissolution is an important chemical indicator for evaluating the effectiveness of interfacial corrosion inhibition—if the FLP effectively captures corrosive species such as HF and H2S, the dissolution of transition metals in the cathode material should be significantly inhibited. Therefore, this indicator can provide evidence for the effectiveness of the FLP chemical capture mechanism.

[0103] Table 2

[0104]

[0105] Results Analysis and Discussion

[0106] Experimental results fully demonstrate the crucial role of the frustrated Lewis pair's acid-base synergistic capture mechanism in maintaining the long-term stability of the NCM / sulfide interface. By comparing the test data of Example E1 with comparative examples CE1 and CE2, a comprehensive performance improvement brought about by the FLP online purification layer can be clearly observed. E1 achieved a capacity retention rate of 87% after 500 cycles at 25°C, while CE1 without any interface modification only achieved 55%, and CE2 with only a LiNbO3 transition layer achieved 72%. E1 still showed a significant improvement of 15 percentage points compared to CE2. This difference excludes the contribution of the physical barrier effect of the transition layer itself, indicating that the active chemical capture mechanism provided by the FLP functionalized nanobrush is a necessary condition for achieving long-term cycling stability.

[0107] The interface impedance data corroborates the above conclusion from another perspective. After 200 cycles, E1's Rct only decreased by 15 Ω·cm. 2 Increased to 35Ω·cm 2 The increase was approximately 133%. CE1, on the other hand, increased from 45Ω·cm. 2 Rapidly increased to 180 Ω·cm 2 The increase reached 300%. CE2 increased from 25Ω·cm 2 Increase to Ω·cm 2 The increase was 220%. The low initial impedance of E1 indicates that the FLP nanobrush did not affect Li +Transport is significantly hindered, and the slow rate of impedance growth indicates that the FLP effectively inhibits the accumulation of byproducts at the interface by continuously capturing harmful interfacial species. ICP-OES data provide further chemical evidence: after E1 cycling, Ni dissolution in the electrolyte layer was only 15 ppm, while it reached 85 ppm in CE1 and 45 ppm in CE2. The significant reduction in transition metal dissolution indicates that interfacial corrosion is significantly inhibited. Based on this, it is reasonable to infer that the FLP sites effectively capture corrosive species such as HF—Lewis acid sites can capture F… - Anionic, Lewis base sites accept H+ + The two protons work together to fix corrosive small molecules into thermodynamically stable ion pairs, thereby cutting off their continuous corrosion path on the NCM cathode lattice.

[0108] The experimental results of comparative samples CE3 (containing only Lewis acid B(C6F5)3) and CE4 (containing only Lewis base TBD) strongly demonstrate the indispensability of acid-base synergistic capture. CE3 maintained a 76% retention rate after 500 cycles at 25°C, and CE4 maintained 73%. While both were better than CE1's 55%, they still lagged behind E1's 87% by 11 to 14 percentage points. This result indicates that while Lewis acids or Lewis bases alone can capture some harmful species, the capture efficiency of a single site is far less than that of acid-base synergy. From a mechanistic perspective, taking the efficient elimination of HF as an example, this process requires Lewis acid sites to capture HF. - At the same time, Lewis base sites accept H + The two work together to form a thermodynamically stable product. A single site can only complete half of the capture process, while the other half of the species remain at the interface and continue to trigger side reactions. ICP-OES data also reflect the importance of the synergistic effect: the Ni dissolution of CE3 is 35 ppm and that of CE4 is 40 ppm. Although this is significantly lower than the 85 ppm of CE1, it is still more than twice that of E1 (15 ppm).

[0109] The comparative example CE5 grafts the Lewis acid B(C6F5)3 and the Lewis base TBD onto the same polymer chain, eliminating steric frustration. CE5's cycle retention after 500 cycles at 25°C is only 68%, significantly lower than E1's 87%, and even lower than CE3 (76%) and CE4 (73%), which contain only a single acid or base. This seemingly anomalous result actually reveals a core principle of FLP chemistry: when Lewis acids and bases are distributed adjacently on the same chain, they readily undergo intramolecular acid-base neutralization to form classic adducts. The boron atom changes from a three-coordinate sp2 hybrid to a four-coordinate sp3 hybrid, and the empty p orbital is occupied, losing its Lewis acidity; the lone pair electrons of TBD are locked in the BN coordinate bond, and the Lewis basicity is also deactivated. Therefore, CE5 is essentially equivalent to an inert polymer coating containing neither an active Lewis acid nor an active Lewis base; its 65% to 68% cycle retention comes solely from the physical isolation effect of the polymer layer itself.

[0110] In contrast, E1 uses polymer microphase separation technology to immobilize Lewis acids and bases on the A and B backbones, respectively. Utilizing the difference in solubility parameters between the two polymer chains, it forms phase-separated nanodomains on the 8–20 nm scale within the polymer layer. The average spacing of 2–8 nm between Lewis acid sites and Lewis base sites is sufficiently close to synergistically capture small molecules diffusing across domains, while effectively avoiding intramolecular neutralization caused by direct contact. The 19 percentage point difference in retention rate between CE5 and E1, coupled with the fact that CE5 is even inferior to CE3 and CE4, fully demonstrates that the construction of spatially frustrated states is not only a core design element of FLP online purification technology, but its absence can even have negative effects due to acid-base quenching.

[0111] The comparative example, CE6, omits the LiNbO3 transition layer, directly coating the polymer solution onto the bare NCM surface. The initial Rct of CE6 is only 18 Ω·cm. 2 The Rct of CE6 was relatively low across all samples, indicating that the polymer layer itself did not introduce significant interfacial transport resistance. However, after 200 cycles, Rct of CE6 increased sharply to 90 Ω·cm. 2The impedance growth rate reached 400%, the highest among all samples. It exhibited a characteristic behavior of good initial performance followed by a sharp decline over time. Correspondingly, CE6's retention rate after 500 cycles at 25°C was only 65%, and even lower at 52% after 200 cycles at 45°C. This indicates that, in the absence of a LiNbO3 transition layer anchoring, the polymer layer gradually detaches from the NCM surface under the influence of volume changes and interfacial stress caused by repeated charge-discharge cycles. The abundant metal-oxygen bonds on the LiNbO3 transition layer surface provide stable coordination anchoring sites for phosphonic acid or catechol end groups, while the bare NCM surface lacks sufficient chemical anchoring ability and cannot withstand the mechanical shock of long-term cycling. Furthermore, the LiNbO3 transition layer itself provides an electron blocking function, further reducing the driving force of side reactions between the NCM cathode and the sulfide electrolyte at high potentials. Therefore, the functional synergy between the transition layer and the polymer layer is an indispensable part of the overall design.

[0112] The comparative example CE7 uses a ZIF-8 metal-organic framework physical adsorption layer instead of a polymer layer, representing a traditional interface protection strategy based on porous material adsorption. At 25°C, CE7's cycling performance is acceptable: 83% retention after 200 cycles and 70% after 500 cycles, significantly lower than E1's 92% and 87% by 9 and 17 percentage points respectively, with the gap widening with increasing cycle count. However, at 45°C, the difference becomes extremely pronounced: CE7's retention rate drops to 65% after 100 cycles and only 48% after 200 cycles, 23 and 34 percentage points lower than E1's 88% and 82% respectively. This rapid decline in CE7's performance at high temperatures reveals the inherent thermal instability of the physical adsorption mechanism. The adsorption of molecules such as HF and H2S by ZIF-8 mainly relies on van der Waals interactions and weak coordination within the pores. At 45°C, the increased molecular thermal kinetic energy leads to a large amount of desorbed species being released back to the interface, resulting in an inefficient adsorption-desorption cycle. The chemical trapping mechanism of FLP is believed to involve the formation of covalent BF bonds and protonation of TBDH. + Thermodynamically stable products irreversibly immobilize harmful species, and the capture efficiency is relatively less affected by temperature. ICP-OES data also reflects this difference: the Ni dissolution of CE7 (50 ppm) is more than three times that of E1 (15 ppm). In terms of rate performance, the 3C / 0.2C capacity ratio of CE7 is only 65%, lower than E1's 75%, which is related to the greater layer thickness and higher density of ZIF-8 hindering ion transport. Overall, the chemically selective capture of FLP is superior to the MOF physisorption strategy in terms of thermal stability, capture efficiency, and ion transport compatibility.

[0113] The effect of the A:B molar ratio on performance was verified by comparing E2 (6:4) and E3 (8:2) with E1 (7:3). The retention rates of E2 and E3 after 500 cycles at 25°C were 84% and 83%, respectively, both slightly lower than E1's 87%, but the difference was within 5 percentage points. This indicates that the performance change is relatively gradual within the A:B ratio range of 6:4 to 8:2, and the process tolerance is relatively large. E2 has a higher proportion of Lewis base, H... + Acceptance sites are plentiful but F - The capture sites are relatively insufficient; the opposite is true for E3, which has a higher proportion of Lewis acids. The optimal ratio of 7:3 effectively balances the acidic species (F in HF). - SO x ) and basic species (H in HF) + SH in H2S - The capture requirement.

[0114] The effect of polymer thickness on performance was verified by comparing E4 (8 nm) and E5 (20 nm). A ternary constraint relationship between thickness, impedance, and trapping capacity was observed. The initial Rct for E4 was 12 Ω·cm. 2 The Ni dissolution rate was the lowest among all samples, with a 3C / 0.2C ratio of 78%, superior to E1's 75%, indicating that the ultrathin coating has minimal obstruction to ion transport. However, E4's retention rate after 500 cycles at 25°C was 82%, lower than E1's 87%, and its Ni dissolution rate (22 ppm) was higher than E1's (15 ppm), reflecting the limited total number of FLP sites at an 8 nm thickness, resulting in insufficient capture capacity during long cycles. E5 (20 nm) exhibited the opposite characteristics: Ni dissolution rate was only 12 ppm, the lowest among all examples, and its 500-cycle retention rate of 86% was close to E1's level, but the initial Rct increased to 20 Ω·cm. 2 The rate performance dropped to 68%. The complementary performance characteristics of E4 and E5 validated that 10-15 nm is the optimal thickness window for balancing ion transport and chemical trapping.

[0115] The effect of polymer C was verified using E8 (0 mol%) and E9 (20 mol%). E8, which contained no polymer C, showed slightly inferior cycling and impedance data compared to E1. This is because the lack of dilution control with fluorine-rich inert chains reduced the phase separation homogeneity between the A and B backbones, potentially leading to uneven distribution of acid and base sites in localized areas. E9, with 20 mol% polymer C, showed performance similar to but slightly lower than E1, suggesting that excessive inert chains diluted the areal density of effective FLP sites. A 15 mol% polymer C dosage achieved a better balance between promoting phase separation homogeneity and maintaining sufficient FLP site density.

[0116] E6 uses a 1:1 mixture of B(C6F5)3 and B(3,5-(CF3)2C6H3)3 as a Lewis acid, and its retention rate after 500 cycles at 25°C is 85%, only 2 percentage points lower than E1's 87%. Although the Lewis acidity of B(3,5-(CF3)2C6H3)3 is slightly weaker than that of B(C6F5)3, it can still effectively capture F. - and coordination SO x This result verifies the technical feasibility of partially replacing B(C6F5)3 with lower-cost Lewis acid materials, providing flexibility for cost control in industrial applications. In E7, DBU was used instead of TBD as the Lewis base, achieving a 500-cycle retention rate of 83%. While performance decreased, it remained within acceptable limits, indicating that although the cyclic amidine base DBU is inferior to the cyclic guanidine base TBD in this system, it can still effectively perform proton trapping. In E10, catechol was used instead of phosphonic acid as the anchoring group, and its performance was highly similar to E1 (84% retention rate after 500 cycles), verifying that the ortho-diol-metal coordination of catechol with the metal-oxygen bond on the LiNbO3 surface can also provide long-term stable chemical anchoring. These three sets of substitution experiments collectively demonstrate that the FLP nanobrush system has good flexibility in material selection and process robustness.

[0117] E11 replaced the cathode material from NCM811 to NCM622, and all indicators were slightly better than E1: 89% retention after 500 cycles, 12 ppm Ni dissolution, and 90% coulombic efficiency in the first cycle. This result is in line with expectations because NCM622 has a lower Ni content, resulting in weaker surface reactivity and structural instability under high voltage compared to NCM811, and a lower background level of interfacial side reactions. The FLP nanobrush exhibits a more abundant capture margin in a milder interfacial environment. E12 replaced the solid electrolyte from Li6PS5Cl to Li6PS5Br, and the performance was basically the same as E1 (86% retention after 500 cycles), indicating that the FLP nanobrush is applicable to different lithium halide sulfide electrolyte systems. Although the types of interfacial byproducts in the Li6PS5Br system are different from those in Li6PS5Cl, the Lewis acid-base capture mechanism of the FLP site has good versatility for halide anions and protons. E13 changed the transition layer preparation method from ALD to sol-gel (approximately 5 nm thick), achieving a 500-cycle retention rate of 84%, slightly lower than E1's 87%. This difference is primarily due to the sol-gel method producing LiNbO3 layers with slightly lower uniformity and density compared to ALD. Considering the significantly lower equipment cost of the sol-gel method compared to ALD, this result provides a feasible alternative process for large-scale production.

[0118] Based on all test data, the FLP nanobrush interface online purification layers of each embodiment exhibit comprehensive performance advantages. The optimal solution E1 achieved a capacity retention rate of 87% after 500 cycles at 2°C, 82% after 200 cycles at 45°C, with an interface impedance growth rate controlled at 133%, a first-cycle coulombic efficiency of 89%, and a 3C / 0.2C rate performance of 75%, comprehensively outperforming all comparative solutions. Regarding interface corrosion inhibition, the total dissolution of transition metals was reduced by more than 80% compared to the blank control CE1, providing strong experimental evidence for the effectiveness of FLP chemistry in interface applications.

[0119] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A solid-state battery, characterized in that, The device includes a positive electrode and a solid electrolyte in contact with the positive electrode. The positive electrode includes a positive electrode active material and an interface layer on the positive electrode active material. The interface layer includes a transition layer and a polymer layer. The transition layer is located between the positive electrode active material and the polymer layer. The polymer layer includes polymer A and polymer B. Polymer A includes an A main chain and a Lewis acid grafted onto the A main chain. Polymer B includes a B main chain and a Lewis base grafted onto the B main chain. The Lewis acid and the Lewis base constitute a frustrated Lewis pair. The Lewis acid comprises at least one of tris(pentafluorophenyl)borane and tris[3,5-bis(trifluoromethyl)phenyl]borane; the Lewis base comprises at least one of cyclic guanidine bases and cyclic amidine bases; the cyclic guanidine base comprises 1,5,7-triazabicyclo[4.4.0]dec-5-ene; the cyclic amidine base comprises 1,8-diazabicyclo[5.4.0]undec-7-ene; The transition layer comprises LiNbO3; the thickness of the transition layer is 2nm~5nm.

2. The solid-state battery according to claim 1, characterized in that, The average spacing between the Lewis acid and the Lewis base is 2 nm to 8 nm.

3. The solid-state battery according to claim 1, characterized in that, The polymer A satisfies at least one of the following conditions: (1) The main chain of A is selected from poly(meth)acrylate segments or polynorbornene derivative segments; (2) The polymer A comprises acrylate monomers and comonomers containing active side groups; the acrylate monomers are selected from at least one of 2,2,2-trifluoroethyl methacrylate, 2,2,3,3,3-pentafluoropropyl methacrylate and 2,2,3,3-tetrafluoropropyl methacrylate; the comonomers containing active side groups are selected from at least one of glycidyl methacrylate and hydroxyethyl methacrylate. (3) The main chain of A has a linking group, which is formed by the connection of a nucleophilic group and an active side group. The nucleophilic group is the end-capping group of the Lewis acid, selected from at least one of primary amino, hydroxyl and thiol groups. The active side group is provided by a comonomer containing an active side group, which is selected from at least one of glycidyl methacrylate and hydroxyethyl methacrylate. (4) The end capping group of the polymer A includes an anchoring group, which is selected from phosphonic acid, phosphonate ester, catechol or hydroxamic acid.

4. The solid-state battery according to claim 1, characterized in that, The polymer B satisfies at least one of the following conditions: (1) The B main chain is selected from poly(meth)acrylate segments or polynorbornene derivative segments; (2) The polymer B comprises acrylate monomers and comonomers containing active side groups, wherein the acrylate monomers are selected from at least one of 2,2,2-trifluoroethyl methacrylate, 2,2,3,3,3-pentafluoropropyl methacrylate and 2,2,3,3-tetrafluoropropyl methacrylate; and the comonomers containing active side groups are selected from N-hydroxysuccinimide acrylate. (3) The B main chain has a linking group, which includes at least one of urea and amide groups; the Lewis base is grafted onto the B main chain through the linking group; (4) The end capping group of the polymer B includes an anchoring group, which is selected from phosphonic acid, phosphonate ester, catechol or hydroxamic acid.

5. The solid-state battery according to claim 1, characterized in that, The polymer A includes 3 to 8 Lewis acids, with C6 to C10 segments spaced between adjacent Lewis acids.

6. The solid-state battery according to claim 1, characterized in that, The polymer B includes 2 to 5 Lewis bases, with adjacent Lewis bases separated by C6 to C10 segments.

7. The solid-state battery according to claim 1, characterized in that, The molar ratio of polymer A to polymer B is (6~8):(2~4).

8. The solid-state battery according to claim 1, characterized in that, The number-average molecular weight of polymer A is 8kDa~25kDa, and the polydispersity index (PDI) is ≤1.

5.

9. The solid-state battery according to claim 1, characterized in that, The number-average molecular weight of polymer B is 8kDa~20kDa, and the polydispersity index (PDI) is ≤1.

5.

10. The solid-state battery according to any one of claims 1 to 9, characterized in that, The polymer layer further includes polymer C, which satisfies at least one of the following conditions: (1) The polymer C comprises perfluoroalkyl methacrylate segments; (2) The polymer monomer of the polymer C includes 1H,1H,2H,2H-perfluorooctyl methacrylate; (3) The number-average molecular weight of polymer C is 8kDa~15kDa; (4) The polymer C accounts for 10~20 mol of the total number of moles of the polymer.

11. The solid-state battery according to any one of claims 1 to 9, characterized in that, Includes at least one of the following features: (1) The thickness of the polymer layer is 8 nm to 20 nm; (2) The weight of the polymer layer accounts for 0.25wt% to 0.5wt% of the weight of the positive electrode active material.

12. The solid-state battery according to any one of claims 1 to 9, characterized in that, Includes at least one of the following features: (1) The positive electrode active material includes at least one of NCM811, NCM622, NCM9055 and NCA; (2) The solid electrolyte includes a sulfide solid electrolyte, which includes Li6PS5Cl, Li6PS5Br, Li6PS5I, and Li7P3S. 11 and L 10 GeP2S 12 At least one of them; (3) The solid-state battery further includes a negative electrode, which is in contact with the solid electrolyte and separated from the positive electrode by the solid electrolyte. The negative electrode includes a lithium metal negative electrode or a lithium alloy negative electrode.

13. A battery device, characterized in that, The battery device includes a solid-state battery as described in any one of claims 1 to 12, and the battery device includes one or more of a battery module, a battery pack, and an energy storage battery.

14. An electrical appliance, characterized in that, The electrical device includes the battery device as described in claim 13, the battery device being used to provide electrical energy.

15. An energy storage device, characterized in that, The energy storage device includes the battery device as described in claim 13, the battery device being used to store electrical energy.

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