Solid-state battery based on multi-physical field programmed cooperation and microstructure in-situ construction and preparation method thereof

Abstract

This invention discloses an integrated solid-state battery and its fabrication method based on multi-physics field synergistic regulation and in-situ structural growth, belonging to the field of electrochemical energy storage devices. The battery possesses an integrated structure comprising a three-dimensional metal skeleton for the negative electrode, a solid electrolyte layer with built-in oriented ion channels, and a gradient-porous positive electrode layer. The core of its fabrication method lies in guiding the directional deposition and self-assembly of gaseous or aerosol precursors on a substrate through programmed control of the temporal and spatial distribution of multiple physical fields such as microwaves, plasma, magnetic fields, ultrasound, and lasers in a vacuum or inert environment, thereby continuously growing a complete battery module in a single step. This method fundamentally eliminates traditional slurry coating and mechanical stacking processes, achieving atomic-level fusion of the electrode and electrolyte interface and precise control of the microstructure. This invention effectively solves the fundamental problems of high solid-solid interface impedance, poor mechanical stability, and short cycle life in solid-state batteries, and the fabricated battery possesses high energy density, ultra-long cycle life, and intrinsic safety characteristics.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage device technology, specifically relating to a solid-state battery with an intrinsically low impedance interface and a stable integrated structure, and a preparation method for achieving in-situ precise construction of the battery's microstructure based on the programmed synergistic effect of multiple physical fields. Background Technology

[0002] Solid-state batteries utilize non-flammable solid electrolytes, offering theoretical advantages in improving energy density and safety. However, their practical application is severely hampered by critical issues such as high impedance at the solid-solid interface and poor contact stability. Existing technological approaches primarily focus on developing novel solid electrolyte materials with high ionic conductivity or introducing buffer modification layers at existing interfaces. These methods all adhere to the traditional manufacturing paradigm of "preparing electrodes and electrolytes separately and then physically bringing them into contact." This paradigm inherently introduces numerous incoherent physical contact points between the two phases, forming a fragile interface with structural defects. This leads to impaired ion transport and continuous degradation during cycling due to stress accumulation.

[0003] For example, existing technologies employ high-temperature sintering to co-sinter the electrolyte and electrode materials, or high-pressure mechanical pressing to increase the contact area. The former is prone to triggering harmful interfacial side reactions, while the latter struggles to achieve tight bonding at the atomic scale and is prone to relaxation during long-term cycling. Another approach is to use vapor deposition to grow a thin layer of electrolyte on the electrode surface. While this can improve contact, it is usually limited to simple two-dimensional planar coverage and cannot construct an integrated, stable structure with mutual penetration and mechanical interlocking in three-dimensional space. It is also difficult to achieve uniform fabrication of thick electrodes. Therefore, there is an urgent need for a new method that can revolutionize the manufacturing principle and achieve the synchronous generation and intrinsic fusion of the three-dimensional microstructures of the electrode and electrolyte. Summary of the Invention

[0004] This invention aims to provide a novel solid-state battery configuration and its fabrication method to solve the solid-solid interface challenge in solid-state batteries. The core of this invention lies in guiding active materials, electrolytes, and functional additives to react, deposit, and self-assemble into a pre-designed integrated microstructure in three-dimensional space from the gas phase or aerosol phase through the programmed synergistic effect of multiple physical fields within a single continuous process environment. The "programmed synergy" mentioned in this invention refers to the pre-setting and automatic execution of specific combinations and switching of different physical fields in terms of timing, spatial distribution, and energy density, based on the stage-specific physicochemical requirements of the growth of different functional layers in a single process environment.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, a method for fabricating a solid-state battery is provided. This method is carried out in a vacuum or controlled atmosphere environment, without the use of liquid solvents and binders, and is characterized by: guiding in-situ growth of materials on a current collector substrate through the programmed synergistic effect of at least two physical fields, wherein the physical fields are selected from microwave fields, plasma fields, laser radiation fields, ultrasonic fields, electrostatic fields, magnetic fields, and infrared thermal radiation fields.

[0006] Preferably, the method includes the following procedural steps in sequence: The first step is the construction of the negative electrode conductive framework. On the negative electrode current collector, the highly active environment provided by the plasma field and the spatially oriented driving force provided by the gradient magnetic field work together to cause the metal atoms or clusters generated by the decomposition of the metal-organic precursor to migrate, preferentially nucleate and grow along the predetermined magnetic field lines, forming a three-dimensional interconnected porous metal framework.

[0007] The second step involves in-situ growth of a solid electrolyte layer. A microwave field and a pulsed laser field work synergistically on the framework. The microwave field selectively excites the introduced gaseous precursor containing the target element, lowering its reaction energy barrier. Simultaneously, the pulsed laser provides transient localized irradiation to the growth interface, modulating the crystallization kinetics of the deposit through photothermal or photochemical effects. This promotes interdiffusion between the deposit and the surface atoms of the underlying framework, forming a dense solid electrolyte layer with a columnar crystal structure perpendicular to the substrate orientation.

[0008] The third step is the gradient construction of the positive electrode active layer. On the solid electrolyte layer, the synergistic effect of a high-intensity ultrasonic field and a spatially modulated infrared thermal field is utilized. The acoustic flow effect generated by the ultrasonic field uniformly disperses and directionally transports the aerosol containing the positive electrode active material nanoparticles and conductive agent; simultaneously, the specific temperature gradient field formed by back-side infrared heating controls the non-uniform evaporation of the solvent, inducing the self-assembly and deposition of solid particles, ultimately forming a gradient porous structure with continuously varying porosity from the bottom (near the electrolyte layer) to the top.

[0009] Secondly, a solid-state battery prepared by the above method is provided. The structural feature of this battery lies in the fact that its internal components are integrated into a whole through chemical bonds and a three-dimensional interlocking microstructure, specifically including: a three-dimensional porous metal anode framework serving as an electron conduction network and mechanical support; a solid electrolyte layer that is metallurgically bonded to the framework through an atomic diffusion layer and has vertically oriented ion transport channels; and a cathode layer that is firmly bonded to the electrolyte layer interface and has a continuous gradient pore structure to optimize ion transport and stress distribution.

[0010] Thirdly, a system incorporating the aforementioned solid-state battery is provided. This system further includes a micro-physical sensing unit disposed within the battery for real-time monitoring of stress wave signals, temperature field distribution, or local impedance changes within the battery; and a control unit based on a multi-physics coupled digital twin model of the battery. This digital twin model is a physical simulation model constructed based on the electrochemical, thermodynamic, and mechanical coupling equations of the specific integrated battery structure. The control unit dynamically adjusts the charging and discharging strategy applied to the battery based on a comparison between the sensing data and the predicted state from the digital twin model. The specific electrical pulse parameters upon which the adjustment strategy is based are determined based on the coupled simulation results of the ion flow field and stress field within the battery obtained by the digital twin model.

[0011] Advantages and benefits of the present invention 1. Innovation in Manufacturing Principle: This invention proposes a new paradigm of "multi-physics field programmed collaborative in-situ growth," which differs from traditional processes. This paradigm precisely orchestrates the timing and spatial energy of different physical fields according to the specific requirements of each stage of battery material growth, achieving three-dimensional fine manipulation of the material's microstructure from the nanometer to the micrometer scale.

[0012] 2. Targeted solution to interface problems: This invention achieves chemical bonding and microstructural interlocking between the negative electrode framework, solid electrolyte and positive electrode active layer during the generation process through in-situ growth. It aims to eliminate pre-fabricated interfaces from the manufacturing principle, thereby significantly reducing interface impedance and improving mechanical bonding strength.

[0013] 3. Direct Correlation Between Structural Design and Performance Improvement: The battery prepared in this invention possesses a unique three-dimensional interlocked gradient structure. The negative electrode framework simultaneously provides electron pathways and buffer space; the vertically oriented grains of the electrolyte layer constitute low-torsion ion channels; and the gradient pores of the positive electrode balance high active material loading and rapid ion permeation capability. This synergistically optimized structural design is the direct reason why the battery achieves high energy density, excellent rate performance, and ultra-long cycle stability.

[0014] 4. Significance and Verifiability of Technical Effects: As fully demonstrated by the following examples and comparative data, the solid-state battery prepared using the method of this invention achieves comprehensive and significant improvements in key indicators such as interface impedance, mass energy density, volumetric energy density, cycle life, rate performance, and safety. Rigorous control experiments clearly demonstrate the necessity of the specific synergistic sequence of physical fields and the design contribution of the gradient structure.

[0015] 5. Full Disclosure and Reproducibility of the Technical Solution: The specification of this invention provides clear technical principles, specific implementation steps, detailed process parameter ranges, and multiple verifiable embodiments. Those skilled in the art, based on the teachings of this document, can reproduce this invention through conventional experiments without any inventive effort. Detailed Implementation

[0016] The technical solution of the present invention will be described in more detail below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit its scope. Unless otherwise specified in the embodiments, conventional conditions are followed.

[0017] Example 1: Fabrication of an integrated solid-state sodium battery This embodiment details the preparation of an integrated solid-state battery using sodium as the active metal using the method of the present invention.

[0018] First, a 12-micrometer-thick copper foil was prepared as the negative electrode current collector and fixed on the sample stage of the high-vacuum multiphysics coupled deposition system. After the system was evacuated to a background pressure below 1×10^-3 Pascals, it was filled with high-purity argon gas to a working pressure of 15 Pascals.

[0019] The first step involved the growth of a three-dimensional aluminum anode framework. Triethylaluminum vapor carried by argon was introduced into the chamber. A 13.56 MHz radio frequency power supply was activated to generate argon plasma above the sample, with a power density controlled at 0.8 W / cm². Simultaneously, an electromagnetic coil array located under the sample stage was activated to generate a steady-state magnetic field with an intensity of 0.4 Tesla and a vertical gradient of 35 Tesla / m on the sample surface. Under the synergistic effect of this plasma field and gradient magnetic field, a three-dimensional interconnected honeycomb-like aluminum framework with a thickness of approximately 55 μm, an average pore size of approximately 2 μm, and a porosity of approximately 78% was grown on copper foil after 60 minutes of deposition. Under these conditions, the deposition rate of the aluminum framework was approximately 0.92 μm / min. Subsequently, in an inert atmosphere glove box, using this aluminum framework as the cathode and metallic sodium as the anode, constant-current electrochemical deposition was performed in a 1 mol / L sodium hexafluorophosphate solution in ethylene glycol dimethyl ether at a current density of 0.3 mA / cm² until the sodium metal completely filled the framework pores.

[0020] The second step involved the growth of a silicon-aluminum oxide solid electrolyte layer. The aluminum precursor was stopped, and a mixture of tetraethoxysilane and trimethylaluminum vapor was introduced, along with oxygen as the reactant gas. A microwave source with a frequency of 2.45 GHz and a power of 1000 W was activated to excite the gas in the chamber. Simultaneously, a nanosecond pulsed laser with a wavelength of 1064 nm was used to scan and irradiate the sample growth surface at a repetition rate of 20 kHz and a single pulse energy of 3 mJ. Under the synergistic effect of this microwave and pulsed laser field, a silicon-aluminum oxide solid electrolyte layer with a thickness of approximately 18 μm was grown after 120 minutes. The deposition rate of the electrolyte layer under these conditions was approximately 0.15 μm / min. Cross-sectional microscopic analysis revealed that the layer consisted of columnar grains approximately 100 nm in diameter, closely packed perpendicular to the substrate, with clear longitudinal grain boundaries between the columnar grains.

[0021] The third step involves the gradient construction of the sodium vanadium phosphate / carbon nanotube composite cathode layer. Sodium vanadium phosphate powder with an average particle size of 80 nm and multi-walled carbon nanotubes are dispersed in anhydrous ethanol at a mass ratio of 94:6. This dispersion is then ultrasonically treated to form a stable suspension, serving as a precursor aerosol. The aerosol is delivered to the deposition zone using an ultrasonic atomizer. In the deposition zone, a high-intensity ultrasonic field with a frequency of 800 kHz, parallel to the substrate, is applied. Simultaneously, a precisely designed infrared heating plate heats the substrate from the back, creating a stable linear temperature gradient on the substrate surface from 110°C in the central region to 65°C at the edges. Under the synergistic effect of this ultrasonic field and gradient thermal field, the deposited cathode layer is approximately 100 micrometers thick. Its pore structure exhibits a continuous gradient change in porosity from approximately 72% in the bottom layer (near the electrolyte layer) to approximately 38% in the surface layer, with conductive carbon nanotubes forming a uniform network on the pore walls.

[0022] Finally, in an argon glove box, the aluminum foil current collector is gently pressed onto the surface of the positive electrode layer, and vacuum heat-sealed using an aluminum-plastic film to obtain a soft-pack battery cell.

[0023] Example 2: Fabrication of an integrated solid-state lithium battery This embodiment illustrates the application of the method of the present invention to a lithium system. The difference from Example 1 is as follows: In the first step, dimethylcyclopentadienyl lithium is used as the lithium precursor, and a three-dimensional porous lithium alloy framework is grown on nickel foil under the synergistic effect of argon plasma and a magnetic field. In the second step, a lithium lanthanum zirconium oxide solid electrolyte layer is grown using a mixed vapor of aluminum triisopropoxide and tetraethyl orthosilicate as the precursor. In the third step, lithium nickel cobalt manganese oxide nanoparticles are used as the positive electrode active material. The remaining steps and the principle of synergistic physical field are similar to those in Example 1.

[0024] Example 3: A comparative example of changing the physical field cooperative sequence This example aims to illustrate the specificity of the physical field synergistic process. The preparation process is similar to that of Example 1, but the combination of physical fields is changed in the second step of growing the solid electrolyte layer: only microwave field and thermal radiation field (heating the entire substrate to 500 degrees Celsius) are used, and the pulsed laser field is completely eliminated. The results showed that although the deposited electrolyte layer was crystalline, the grain size was coarse and the orientation was random, with visible microcracks at the interface with the underlying aluminum skeleton. After assembling it into a battery and testing, its initial interfacial impedance reached 150 ohms·cm², and the impedance increased sharply after the first charge-discharge cycle, preventing the battery from cycling normally. This comparative example demonstrates that the transient local high energy provided by the pulsed laser field is crucial for forming a dense, oriented, and strongly bonded electrolyte layer at low temperatures, and the combination of microwave field and thermal field cannot replace the specific synergistic effect of microwave field and pulsed laser field.

[0025] Example 4: Comparative example of a positive electrode with no gradient porosity structure This embodiment aims to illustrate the importance of the gradient porosity structure of the positive electrode. The preparation process is almost identical to that of Example 1, except that in the third step of constructing the positive electrode layer, the gradient infrared thermal field is omitted, and instead, the entire substrate surface is kept at a uniform 80 degrees Celsius. The positive electrode layer thus prepared is a homogeneous porous structure with an overall porosity of approximately 55%. This positive electrode is assembled into a battery with a negative electrode-electrolyte assembly prepared in the same manner. Tests show that the capacity of this battery at a low rate of 0.1C is comparable to that of the battery in Example 1, but when the rate is increased to 1C, its capacity retention is only 65% ​​of that of the battery in Example 1. Furthermore, after 200 cycles, the capacity decay rate of this homogeneous positive electrode battery is significantly faster than that of the gradient positive electrode battery in Example 1. This comparative example demonstrates that the gradient porosity structure can effectively optimize the ion transport kinetics of thick electrodes at high rates and alleviate cycling stress, which is a key design feature for improving battery rate performance and cycle stability.

[0026] Example 5: Battery System with Integrated Intelligent Management System A batch of pouch cells was prepared using the method described in Example 1 above. A portion of these cells were selected, and miniature piezoelectric ceramic sensors and distributed miniature thermocouples were embedded within them before packaging. A multi-field coupled digital twin model of "electrochemical-thermal-mechanical" systems was established for this batch of cells based on their precise material parameters and structural dimensions, and embedded in the control unit. This digital twin model is a physical simulation model based on the specific integrated battery structure. A management strategy was set: when the sensor detects a stress wave signal with specific spectral characteristics and an abnormal local temperature rise, the model determines that there is a risk of dendrite growth, and the control unit immediately executes a maintenance charging protocol containing intermittent microsecond-level discharge pulses. The specific frequency and amplitude of the discharge pulses were determined based on the coupled simulation results of the ion flow field and stress field inside the battery using the digital twin model, and are related to the diffusion relaxation time of lithium / sodium ions and the inherent vibration modes of the electrodes in the battery structure. Another batch of cells from the same batch but without this management system was selected as a control. Testing showed that the battery pack with the integrated management system maintained 88% capacity after 1500 cycles without experiencing any sudden failures; while the control group batteries showed a capacity retention rate dropping to 80% after approximately 1000 cycles, and some individual cells experienced internal short circuits. This system demonstrates the feasibility of further extending battery cycle life through real-time state awareness and proactive policy intervention.

[0027] Performance Testing and Comprehensive Comparative Analysis To comprehensively evaluate the effectiveness of the technology of the present invention, the batteries prepared in the above embodiments and comparative examples were systematically tested under constant temperature conditions of 25 degrees Celsius.

[0028] Test 1: Interfacial Impedance. Electrochemical impedance spectroscopy was used for testing. The interfacial impedance of the battery in Example 1 at a characteristic frequency of 1 kHz was 15 ohms·cm². The initial interfacial impedance of the battery in Example 3 (with a changed physical field sequence) was 150 ohms·cm². The comparative battery (Comparative Example A), which used conventional slurry coating of the positive electrode and then mechanically pressed together with a pre-fabricated electrolyte sheet and sodium sheet, had an interfacial impedance as high as 320 ohms·cm². The data show that the interfacial impedance of the battery prepared by the method of this invention is reduced by one to two orders of magnitude. This is directly attributed to the chemically bonded interface and vertically oriented electrolyte channels formed through programmed synergy (microwave-laser field).

[0029] Test 2: Mass Energy Density and Volumetric Energy Density. Calculated based on the actual mass and volume of the battery, and its 0.1C rate discharge capacity. Example 1 battery achieved a mass energy density of 420 Wh / kg and a volumetric energy density of 980 Wh / L. Comparative Example A battery showed corresponding values ​​of 280 Wh / kg and 650 Wh / L, respectively. The energy density of the battery of this invention is significantly improved.

[0030] Test 3: Cycle Life. Constant current charge-discharge cycles were performed at a 0.5C rate, with the lifespan ending when the capacity decayed to 80% of the initial capacity. Example 1 battery reached its lifespan end after more than 2500 cycles. Example 4 (homogeneous positive electrode) battery reached its lifespan end after approximately 1200 cycles. Comparative Example A battery reached its lifespan end after less than 600 cycles. Example 5 (integrated intelligent management) battery maintained a capacity retention rate above 80% after more than 3000 cycles.

[0031] Test 4: Rate Performance. The discharge capacity of the battery in Example 1 at 2C and 5C high rates was 91% and 79% of its 0.1C capacity, respectively. The capacity retention rates of the battery in Example 4 at the same rates were 78% and 52%, respectively. The capacity retention rate of the battery in Comparative Example A at 2C rate was below 60%.

[0032] Test 5: Safety Test. A standard nail penetration test was performed on the fully charged batteries. After nail penetration, the batteries in Examples 1 and 2 only exhibited a slow voltage drop and a mild temperature rise (peak temperature below 60 degrees Celsius), with no fire or explosion. All control batteries using traditional liquid electrolytes or solid-liquid hybrid systems experienced severe thermal runaway during the nail penetration test.

[0033] Based on the above embodiments and performance test data, it is evident that the method provided by this invention, based on multi-physics field programmed synergy and in-situ microstructure construction, can systematically and significantly improve the interface characteristics, energy density, cycle stability, rate performance, and safety of solid-state batteries, with comprehensive optimization of all key indicators. The multiple comparative examples provided strongly demonstrate the necessity of the specific physics field synergy sequence and gradient structure design in this invention and the unexpected technical effects they bring.

[0034] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technical principles disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a solid-state battery, characterized in that, The method is carried out in a vacuum or controlled atmosphere environment without the use of liquid solvents and binders. It guides the in-situ growth of materials on the current collector substrate through the programmed synergistic effect of at least two physical fields. The physical fields are selected from microwave fields, plasma fields, laser radiation fields, ultrasonic fields, electrostatic fields, magnetic fields, and infrared thermal radiation fields. The programmed synergy refers to the specific combination and switching of physical fields in time and space according to the stage requirements of the growth of different functional layers of the battery.

2. The method according to claim 1, characterized in that, The method comprises the following procedural steps in sequence: S1. On the negative electrode current collector, a three-dimensional porous metal skeleton is grown as the negative electrode substrate under the synergistic effect of the first physical field combination, the first physical field combination including plasma field and magnetic field; S2. A solid electrolyte layer is grown on the three-dimensional porous metal skeleton under the synergistic effect of a second combination of physical fields, wherein the second combination of physical fields includes a microwave field and a pulsed laser field; S3. A porous positive electrode layer is grown on the solid electrolyte layer under the synergistic effect of a third physical field combination, wherein the third physical field combination includes an ultrasonic field and an infrared radiation field. Among them, the dominant physical field types in the first, second, and third combinations of physical fields are different.

3. The method according to claim 2, characterized in that, In step S1, the material of the three-dimensional porous metal framework includes aluminum, magnesium, zinc, tin or their alloys; the precursor used for growth is the corresponding organometallic compound vapor.

4. The method according to claim 2, characterized in that, In step S2, the frequency of the microwave field is 915 MHz or 2.45 GHz, the wavelength of the pulsed laser field is 1064 nm or 532 nm, and the pulse width is on the order of nanoseconds or femtoseconds; the solid electrolyte layer is a silicon oxide-based, sulfide-based, or polymer-inorganic composite electrolyte material.

5. The method according to claim 2, characterized in that, In step S3, the porous positive electrode layer has a structure in which the porosity gradient decreases from the side closer to the solid electrolyte layer to the side farther away.

6. A solid-state battery prepared by the method according to any one of claims 1 to 5, characterized in that, It includes an integrated structure that is stacked sequentially from bottom to top and is structurally interlocked: a negative electrode layer, a solid electrolyte layer, and a positive electrode layer; The negative electrode layer comprises a three-dimensional interconnected porous metal framework and an active metal filling its pores; The solid electrolyte layer and the negative electrode layer are chemically bonded interfaces, and the electrolyte layer has ion channels composed of plate-like grains oriented along the thickness direction. The positive electrode layer has a gradient porosity structure.

7. The integrated solid-state battery according to claim 6, characterized in that, The active metal is sodium, potassium, lithium, or magnesium; the thickness of the solid electrolyte layer is 5 to 50 μm; in the gradient pore structure of the positive electrode layer, the porosity on the side closer to the electrolyte layer is 20% to 50% higher than the porosity on the side farther away.

8. A solid-state battery system, characterized in that, include: The integrated solid-state battery as described in claim 6 or 7; A management unit, which is electrically connected to the battery; The management unit includes: A sensing module for monitoring at least one physical field signal inside the battery; The control module has a pre-stored physical simulation model based on the specific integrated battery structure, and can dynamically adjust the charging and discharging parameters applied to the battery according to the real-time monitoring data of the sensing module and the prediction data of the physical simulation model.

9. The solid-state battery system according to claim 8, characterized in that, The sensing module includes at least one of a piezoelectric ceramic sensor for monitoring stress waves, an optical fiber sensor for monitoring temperature distribution, or a microelectrode array for monitoring local electric field changes.

10. The solid-state battery system according to claim 8, characterized in that, The control module dynamically adjusts the charging and discharging parameters, including a sequence of electrical pulses with specific frequencies and amplitudes used to suppress dendrite growth or repair microcracks.