Method for preparing pure-phase doped ternary precursor by spray pyrolysis method based on nitrate system

Abstract

The invention discloses a method for preparing a pure-phase doped ternary precursor by a spray pyrolysis method based on a nitrate system, and relates to the technical field of functional oxide material synthesis, and the method comprises the following steps: establishing a time baseline and electric heat flow field chromatography network, carrying out continuous sampling on droplet charge distribution in a spray area, constructing a charge flux spectrum, and calculating the charge flux spectrum. And micro-discharge prior fingerprints are extracted to form a charge space-time reference. According to the method, discharge precursor identification and early warning are realized through charge space-time reference and potential inversion, a crystal nucleus disturbance region is identified in combination with anti-fact backtracking, energy redistribution is realized through charge pumping, micro-vortex traction and off-peak driving under the guidance of an energy coupling track, and a closed-loop regulation environment is constructed, so that amorphous generation is inhibited, and the stability of the system is improved. The doping uniformity, the crystal phase purity and the particle size controllability are improved, and the method is suitable for large-scale preparation of high-performance positive electrode materials.

Description

Technical Field

[0001] This invention relates to the field of functional oxide material synthesis technology, specifically to a method for preparing pure-phase, doped ternary precursors using a spray pyrolysis method based on a nitrate system. Background Technology

[0002] "Preparation of Pure-Phase, Doped Ternary Precursors by Spray Pyrolysis Based on Nitrate Systems" refers to a chemical method for preparing multi-component composite oxide precursors using metal nitrate solutions as raw materials through spray pyrolysis. The basic principle is as follows: First, metal nitrates such as nickel, cobalt, and manganese are dissolved in water or an alcohol-water system according to a target stoichiometric ratio to form a homogeneous solution with good ion dispersion. Then, the solution is atomized into fine droplets and rapidly evaporated and pyrolyzed in a high-temperature carrier gas field, causing uniform nucleation, diffusion, and phase separation reactions within the droplets, ultimately generating ternary precursor powders with specific particle size, morphology, and compositional distribution. By introducing dopant ions (such as Al, Mg, Ti, Zr, etc.) into the nitrate system, ectopic substitution or lattice modification can be achieved during crystal formation, thereby improving the performance of the subsequently sintered cathode material in terms of structural stability, electronic conductivity, and cycle life. This method features a short reaction path, controllable particle size, uniform element distribution, and suitability for continuous production, making it an important process route for preparing high-performance lithium battery cathode precursors.

[0003] The existing technology has the following shortcomings:

[0004] In existing technologies, when a high-conductivity nitrate system is used as the precursor solution for spray pyrolysis, the overall conductivity of the solution is significantly enhanced due to the high concentration of metal ions and nitrate ions during the electric field-driven spraying process. At this time, the droplets are highly susceptible to uneven electric field distribution during the atomization and spraying stage, leading to significant differences in the charge state between different droplets. Some droplets, under excessive charge conditions, form localized charge-rich regions. When these droplets aggregate or come into contact with each other in the transport channel, charge redistribution triggers transient discharge phenomena. Especially after entering the high-temperature pyrolysis zone, local discharge is further intensified, forming microscale plasma clusters. This micro-plasma generates a transient high-temperature field far exceeding the average furnace temperature in a very short time, disrupting the ordered intercalation sequence that metal ions within the droplets should follow during the crystal growth stage. This causes some metal ions to deviate from their in-situ diffusion paths, resulting in crystal nucleus instability. The result is the formation of amorphous clusters with disordered structure and uneven energy states. These amorphous phases are difficult to transform back into the target crystalline phase during subsequent annealing or sintering, which seriously affects the uniformity of doping and the controllability of pure phase formation, becoming a hidden but serious potential failure factor in the existing technology.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing pure-phase, doped ternary precursors by spray pyrolysis based on a nitrate system, in order to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing pure-phase, doped ternary precursors based on a nitrate system by spray pyrolysis, comprising the following steps:

[0008] A time baseline and electrothermal flow field tomography network were established to continuously sample the droplet charge distribution in the spray area, construct a charge flux spectrum, extract the micro-discharge prior fingerprint, and form a charge spatiotemporal reference.

[0009] Based on the charge spatiotemporal reference, phase difference mapping is performed, and the charge potential energy distribution is analyzed by Laplace-Poisson inversion to determine the charge enrichment nuclei and calculate the aggregation trigger threshold.

[0010] Based on the aggregation triggering threshold, a picosecond-level spectral monitoring mechanism is introduced to collect the nitrogen oxide luminescence intensity ratio and microcurrent pulse sequence, identify the microplasma precursor state, and establish a dynamic early warning chain.

[0011] Based on the output of the dynamic early warning chain, the counterfactual replay chain is invoked to simulate the charge evolution path, reconstruct the ion intercalation failure process, generate the structural instability mapping, and construct the particle size-dependent suppression strategy boundary.

[0012] Based on the suppression strategy boundary, a doped migration modulator is generated, and a linkage control curve of electric field strength, frequency, pulse width and spray rate is constructed to form an energy balance trajectory.

[0013] Under the constraint of energy balance trajectory, charge pumping, acoustic flow traction and time grid driving are performed, and energy redistribution is achieved through online migration of residual density. A closed-loop dynamic control system is constructed to suppress partial discharge chains.

[0014] Preferably, the charge-spacetime reference formation steps are as follows:

[0015] After establishing a unified time baseline and electrothermal flow field tomography network, multiple time triggering devices are equidistantly deployed along the spray area path to synchronously record the droplet ejection time, thus constructing a three-in-one tomographic observation framework integrating time, electric field, and thermal field.

[0016] Based on the established time and space reference, the droplet charge is sampled in segments using an electrostatic deflection trapping device, and continuous recording of the droplet charge is achieved by combining it with a dual-channel time-of-flight measurement device.

[0017] Based on continuous sampling results, a droplet charge flux density map is constructed, high-risk charge enrichment regions are extracted, and a set of micro-discharge prior fingerprint features is labeled.

[0018] Under the constraint of a unified time baseline, and combined with the droplet flight trajectory, a three-dimensional mapping relationship of space, charge, and time is established to generate a charge spatiotemporal reference atlas.

[0019] Preferably, the calculation process for the aggregation trigger threshold is as follows:

[0020] After establishing a charge spatiotemporal reference, the spray path is divided into multiple main-scale segments and further divided into sub-scale layers. Multiple charge dynamic points are extracted, the charge phase difference is calculated, and a phase difference distribution map is formed.

[0021] Based on the phase difference distribution map, the Laplace-Poisson inversion method is used to calculate the potential field structure, construct the potential gradient distribution map between spatial nodes, and form a complete potential field.

[0022] In the potential field, identify potential extreme points that satisfy the extreme value, the threshold of charge flux change slope and time coherence as charge enrichment nuclei;

[0023] An observation region is constructed around the charge-rich nucleus, the local energy density is calculated, and the aggregation determination factor is calculated based on the ratio of the electrostatic force between droplets to the centrifugal force, thus defining the aggregation trigger threshold of the spray channel.

[0024] Preferably, the process for establishing a dynamic early warning chain is as follows:

[0025] After calculating the aggregation trigger threshold, four regions with the highest charge enrichment and energy density were selected as excitation and acquisition anchor points, and high-resolution optical acquisition channels and current acquisition channels were set up.

[0026] Nitrogen-containing intermediate species in droplets were excited using a picosecond-level pulse excitation source, and the ratio of NO to NO2 luminescence intensity was collected. At the same time, the microcurrent pulse characteristics when the droplet passed through the electrode region were recorded to obtain synchronous spectral and electrical signal data.

[0027] The collected spectral and current features are standardized and input into the micro-discharge prior feature model for identification, and a micro-plasma precursor event map is constructed to generate a dynamic early warning chain with timestamps and spatial coordinates.

[0028] Based on the continuity of high-risk trigger points in time and space, the spray electric field intensity, frequency, and liquid supply rate are adjusted in real time to form a closed-loop dynamic response mechanism for electrical discharge risk.

[0029] Preferably, the criteria for identifying microplasma precursor events include that the ratio of the luminescence intensity of NO to NO2 is greater than three times within a preset time, and the corresponding microcurrent pulse peak exceeds a set current threshold and has a rise edge slope exceeding a predetermined rate. When two consecutive droplet samples that meet the above characteristics appear within a limited time interval, they are marked as high-confidence precursor events.

[0030] Preferably, the process for constructing the suppression strategy boundary is as follows:

[0031] Based on the output results of the dynamic early warning chain, droplet samples marked as first-level risk areas in the spray channel were selected, and spectral data, current sequences, flight time, electric field strength and particle size information were extracted to construct charge density change curves and form counterfactual charge channel maps.

[0032] At spatial nodes with offsets, the charge state of metal ions and lattice insertion positions are extracted, the ion offset index is calculated and the coordinates of abnormal sites are tracked, the ion insertion failure trajectory chain is constructed and a structural instability thermogram is formed.

[0033] Statistical regression was performed on droplet samples of different sizes to calculate the frequency and duration of embedding failure, establish structural instability risk function curves and determine the particle size inhibition boundary;

[0034] Based on the suppression boundary, the spray pressure, temperature range and electric field frequency are linked and controlled to form a particle size-dependent structure suppression control boundary map, thus achieving closed-loop control throughout the entire process.

[0035] Preferably, the energy balance trajectory formation process is as follows:

[0036] Based on the particle size-dependent structural instability boundary, a critical droplet size value is set to classify droplets with high insertion risk and low insertion risk, and four control parameters are established: electric field strength, electric field frequency, pulse width and spray rate.

[0037] By constructing a surface response model between the doping migration offset angle and four control parameters, a doping migration linkage control curve is established, and the curve is loaded into the control loop to achieve automatic matching and updating of parameter combinations.

[0038] Before the droplets enter the pyrolysis zone, a parameter vector is generated based on the real-time particle size, charge state, velocity, and evaporation rate. The optimal parameter combination corresponding to the doping migration linkage control curve is then invoked to construct a dynamically adjustable energy balance trajectory.

[0039] Preferably, under the constraint of energy balance trajectory, charge pumping, acoustic flow traction, and time grid driving are performed, combined with online migration of residual density to achieve energy redistribution, and the steps to construct a closed-loop dynamic control system are as follows:

[0040] Under the constraint of energy balance trajectory, a phase control electrode is set up, and a phase conjugate electric field pulse is triggered based on the change of droplet surface charge density to realize the spatial redistribution of charge density;

[0041] An ultrasonic excitation device is placed in the flight path of the droplets to stimulate a rotating vortex that pulls the boundary layer ions of the droplets to diffuse toward the droplet nucleus, thereby adjusting the uniformity of ion distribution.

[0042] The flight path is divided into uniform time grid regions, and a staggered driving strategy is implemented in high-energy-density sections to adjust the droplet passage time and avoid energy concentration and superposition.

[0043] Identify the energy density residual region, perform spatial migration operation to make high-energy droplets drift laterally to the low-energy region and complete energy diffusion;

[0044] Establish a coupling parameter feedback mapping table, and recursively adjust subsequent control commands based on the results of previous control, thus constructing a closed-loop dynamic intervention mechanism throughout the entire process.

[0045] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0046] This invention achieves real-time identification and dynamic early warning of the discharge precursor state by constructing a charge spatiotemporal reference and a multi-scale potential inversion mechanism; it identifies the key perturbation region for crystal nucleus growth through counterfactual path backtracking and structural instability mapping; and then, guided by the energy coupling trajectory, it achieves the directional migration and redistribution of residual energy through charge pumping, micro-vortex traction, and time staggering, ultimately constructing a stable, closed-loop spray pyrolysis control environment. This not only effectively suppresses the formation of amorphous clusters and improves doping uniformity and crystal phase purity, but also significantly enhances the controllability of the ternary precursor particle size distribution and structural stability, providing an advanced, engineering-feasible process route for the large-scale preparation of high-performance lithium-ion battery cathode materials. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0048] Figure 1 This is a flowchart of the method for preparing pure-phase, doped ternary precursors based on the spray pyrolysis method of the nitrate system according to the present invention. Detailed Implementation

[0049] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0050] This invention provides, for example Figure 1 The method for preparing pure-phase, doped ternary precursors using a spray pyrolysis method based on a nitrate system, as shown, includes the following steps:

[0051] A unified time baseline and electrothermal flow field tomography network were established to continuously sample the charge distribution of droplets in the spray area, construct the droplet charge flux spectrum, extract the micro-discharge prior fingerprint, and form a charge spatiotemporal reference.

[0052] To effectively avoid localized micro-discharge phenomena caused by uneven droplet charge states during the spray pyrolysis of high-conductivity nitrate precursors, which could disrupt the ordered intercalation structure of metal ions, a method is proposed to continuously sample, construct flux, and extract fingerprints of droplet charge behavior within the spray region, thereby establishing a causal and traceable spatiotemporal charge reference. This method includes the following steps:

[0053] The spray area is defined as the spatial path from the atomizing nozzle outlet to the pyrolysis furnace inlet. Six sets of high-frequency nanosecond-level time triggering devices are equidistantly arranged along this path to synchronously record the droplet ejection time. Each triggering device consists of a photoelectric sensor, a high-speed image capture device, and a master timer. An initial trigger signal is generated at the moment of droplet formation using the laser tangential occlusion detection principle, and this time point is defined as the unified baseline moment. To synchronously monitor the droplet trajectory and environmental variables in space, a triaxial laser Doppler velocimeter, a miniature thermocouple array, and a high-sensitivity electrostatic field probe are installed at each time triggering node. The triaxial laser velocimeter measures the velocity vector of a single droplet in the X, Y, and Z directions through cross-interference; the miniature thermocouples detect local temperature gradient changes in the flow field; and the electrostatic field probe collects changes in the background electric field intensity along the droplet's flight path. All three types of data are bound to the time baseline via a signal synchronizer, thus constructing a three-dimensional tomographic observation framework integrating time, electric field, and thermal field. This framework ensures that all physical state changes in the spray path are spatiotemporally synchronized, providing stable and accurate reference coordinates for subsequent sampling of droplet charge behavior.

[0054] After establishing temporal and spatial references, a high-voltage electrostatic deflection trapping device was used to sample the droplet charge. This device consisted of three sets of parallel metal electrodes of opposite polarity. As the droplet flew through the electrode channels, it was deflected to varying degrees by the electric field. The magnitude and polarity of its charge could be inferred from the deflection amplitude. A charged particle collector was placed behind each electrode; once a particle struck its surface, it triggered a charge-induction amplifier to record the instantaneous charge value. To improve temporal resolution, the spacing between each sampling point was set to 10 cm, ensuring continuous recording of charge changes in different spatial segments during the droplet's motion. Simultaneously, to eliminate random errors caused by airflow disturbances during flight, a dual-channel time-of-flight measurement device was introduced. This device recorded the droplet's flight time from one sampling point to the next, and combined with its mass and volume, the droplet's motion state and surface charge change trend during this process were inferred. By temporally integrating droplet samples from different time segments under a unified time baseline, a charge sampling dataset with a complete time chain was constructed. Compared to existing methods that use single-point static charge measurement, this method enables precise and continuous tracking of the dynamic charging behavior of a single droplet throughout the entire spray path.

[0055] To accurately reconstruct the overall charge distribution characteristics of droplet swarms in the spray path, a three-dimensional charge distribution matrix was first established based on flight time and sampling location. The spatial coordinates, charge polarity, charge quantity, and flight velocity of each droplet were mapped onto a unified time axis, resulting in a time-segmented droplet charge flux density map. In this map, the rate of change of total net charge per unit space was defined as flux intensity, and flux equipotential lines were plotted for different time segments. Subsequently, a multi-segment, multi-point local incremental fitting method was used to numerically integrate the slope of the charge flux density change, identifying regions of abrupt slope changes—these regions are high-risk charge enrichment areas. Within each abrupt change region, representative charge flux curves were further extracted, and their peak frequency, duration, positive / negative pole switching rate, and symmetry were labeled using feature engineering methods. Principal component analysis was used to extract common factors, forming a multi-dimensional set of charge behavior features. Finally, the set of charge behavior features with high frequency and stable characteristics was defined as the micro-discharge prior fingerprint set. This fingerprint set represents the precursory behavior of droplet swarms that has a high probability of causing transient discharges during atomization and transport. This step, in the absence of existing technologies for droplet swarm flux modeling and fingerprint feature extraction mechanisms, is the first to achieve structured predictive modeling of the micro-discharge formation mechanism.

[0056] To ensure the causal traceability of charge evolution during spraying, the previously extracted charge flux spectrum was first subjected to partitioned interpolation on the time axis, decomposing the charge change process into multiple continuous transition states over time periods. Then, the spatial nodes containing the micro-discharge fingerprint were back-matched to the charge evolution paths within the corresponding time periods. Based on this, a three-dimensional spatial-charge-time mapping was established using the droplet flight trajectory as an index, integrating all droplet charging processes into a visualized evolutionary map. After the evolutionary map was constructed, the charge slope and fingerprint overlap rate in each spatiotemporal grid were further calculated, and this value was labeled as a discharge risk weight. The resulting spatiotemporal charge reference map not only clearly describes the charging trend of a specific droplet within a specific time period but also indicates which regions possess the structural evolution patterns with the highest probability of micro-discharge. This map will provide a highly reliable and traceable foundational data platform for subsequent aggregation threshold calculation, charge potential energy inversion, and suppression strategy design, constituting a crucial data support link from charge behavior diagnosis to full-process intervention.

[0057] Based on the charge spatiotemporal reference, multi-scale phase difference mapping is performed, and the charge potential energy distribution field is analyzed by the Laplace-Poisson inversion method to determine the location of charge enrichment nuclei and calculate the aggregation trigger threshold.

[0058] After establishing a charge-space-time reference with a unified time baseline and an electrothermal flow field tomography network, in order to achieve analytical analysis of the charge potential energy distribution in the spray region and determine the physical boundary conditions for droplet aggregation triggering, the following steps were taken to perform multi-scale phase difference mapping and Laplace-Poisson inversion operations:

[0059] Based on the generated charge spatiotemporal reference atlas, the spray path was divided into multiple main-scale segments, each 20 mm long, covering the complete charge evolution stages experienced by the droplets during flight. Within each main-scale segment, multiple sub-scale layers were further divided radially at 5 mm intervals, forming a spatial grid structure with both longitudinal and radial resolution capabilities. Subsequently, three representative charge dynamic points in each sub-scale layer were selected as phase calculation base points, and the charge change rate sequences of these points were extracted under a unified time baseline. By comparing the charge increase / decrease rates at different base points at the same time, the local charge response lag time difference was calculated, and this lag value was converted into a phase angle. The resulting phase difference values ​​were superimposed onto the spatial grid in pseudo-color image form to form a preliminary phase difference distribution map. This distribution map accurately reflects the inconsistency of charge response speed in multi-scale space, especially exhibiting significant phase distortion in charge-rich regions, providing a physical basis for subsequent potential field inversion.

[0060] After phase difference mapping, the Laplace-Poisson inversion method is used to analyze the electric potential field structure in the spray space. First, five continuous principal scale segments are selected, and the charge density and phase difference values ​​of each sub-scale unit are extracted as input data sources. In three-dimensional space, each sub-scale unit is used as a computation node, and the charge gradient direction and phase response delay between it and its adjacent nodes are set as boundary weights. The potential change trend is iteratively calculated between nodes using the numerical finite difference method. To ensure the stability of the inversion, a continuous potential boundary is set in the spray direction, and a reflection boundary is set in the radial direction to constrain the closed nature of the electric field within the spray channel. Finally, after the electric potential field calculation is completed, different potential energy levels are visualized using contour surfaces, with steep potential regions appearing as local high-energy-density "valleys." Unlike traditional methods that simplify the solution through the mean field assumption, this method embeds the charge response hysteresis into the inversion model, significantly enhancing the dynamic adaptability of the potential field in the time dimension and accurately presenting the actual electric field pattern constituted by the complex charge behavior between droplets.

[0061] In the established potential distribution map, local extrema are identified as candidate locations for charge enrichment nuclei. To eliminate noise interference, a triple verification condition is set: first, the potential value at this point must be the maximum among at least six neighboring nodes; second, this point must also be an extremum in two adjacent time sections; and third, the slope of the charge flux variation in the sub-scale unit to which this point belongs must be greater than 1.5 times the average. Those meeting these conditions are defined as charge enrichment nuclei. A spherical observation region with a diameter of 10 mm is constructed centered on the charge enrichment nucleus, and potential gradient and charge density data for all sub-scale units within this region are collected. The local energy density distribution per unit volume is calculated using spatial integration methods and visualized as an isodensity curve. The peak energy density region indicates that the region possesses sufficiently strong electrostatic potential energy to induce discharge behavior under perturbation conditions. This energy density map not only provides a spatial evaluation of charge accumulation intensity but also provides physical explanation for the local energy accumulation characteristics before aggregation behavior occurs.

[0062] In the identified charge-rich nuclei, the conditions for aggregation are assessed by calculating the ratio between the electrostatic force between droplet pairs and the centrifugal force sustaining droplet flight. First, the surface potential is calculated based on the average droplet surface area and the measured net charge. Then, the interaction force between the two droplets is derived using Coulomb's law, taking into account the minimum distance between them. Finally, the centrifugal force is calculated based on the droplet's flight velocity and center-of-mass radius. The ratio of the interaction force to the centrifugal force is set as a criterion factor; a value greater than 1.0 is considered to satisfy the aggregation triggering condition. This calculation is performed on all enrichment nuclei, and the highest criterion factor value is extracted and increased by 5%, defined as the aggregation triggering threshold for the entire spray channel. This threshold is used to determine whether any region has the potential risk of triggering droplet aggregation. In subsequent real-time monitoring and control, this value will serve as the physical boundary for dynamic early warning.

[0063] Based on the aggregation triggering threshold, a picosecond-level spectral monitoring mechanism is introduced to collect the nitrogen oxide luminescence intensity ratio and microcurrent pulse sequence, identify the microplasma precursor state, and establish a dynamic early warning chain for electrical discharge risk.

[0064] After inverting the charge potential energy distribution field and calculating the aggregation triggering threshold, high-precision monitoring is needed within the possible locations and time windows for micro-discharge to identify the precursor states of micro-plasma formation. To this end, a method integrating picosecond-level spectral acquisition and highly sensitive micro-current signal analysis is proposed to establish a real-time dynamic early warning chain for electrical discharge risks. The specific implementation process is as follows:

[0065] By obtaining the aggregation trigger threshold distribution map, four core regions with the highest charge enrichment and most concentrated energy density distribution within the spray channel were identified as physical anchor points for excitation and acquisition. Two high-resolution optical acquisition channels with a 15 mm spacing were established on both sides of each anchor point along the spray direction. Each channel consists of a pulse excitation source, a timing matching controller, a dispersive mirror group with a bandwidth covering 180–260 nm, and a four-stage photoelectric amplifier. The excitation source uses a xenon flash lamp with an output pulse width of 10 picoseconds, a single-shot energy of 1 millijoules, and a repetition frequency set to 1 million Hz. The pulse excitation synchronization controller is bound to the start trigger of the spray nozzle, activating 20 microseconds before the droplet enters the target region to ensure that excitation is completed before the droplet reaches a high-energy enrichment state. The dispersive mirror group uses a combination of prisms and mirrors for secondary wavelength separation, outputting the spectral distribution at equal intervals of 250 wavelength points to a photomultiplier array. After intensity amplification by the amplifier, the signal is connected to a data acquisition card to achieve time-resolved spectral acquisition of a single droplet. The acquired signals cover the main emission spectra of nitrogen-containing intermediate species such as NO, NO2, and N2O formed during the thermal decomposition of nitrate. The excitation peak of NO molecules is at 226 nm, and that of NO2 is at 247 nm, which are used as important bands for subsequent feature extraction.

[0066] Four coaxial electrode pairs are deployed in each target area, with an electrode length of 20 mm and an electrode spacing of 5 mm. When a droplet flies over the electrode area, its surface charge undergoes a slight shift under the induction of the electric field, resulting in charge redistribution and inducing a very short-lived current signal between the electrodes. Each electrode pair is connected to a high-frequency response charge amplifier with a bandwidth of 10 MHz and a minimum detectable charge change of 10⁻¹⁴ coulombs. The output signal is converted into a standard current pulse sequence through charge integral transformation and sampled and calibrated using a time-to-digital converter to obtain the complete time-domain characteristics of the micro-current disturbance during the flight of a single droplet. Each sampling sequence includes four key indicators: rise time, peak current, current stabilization period, and fall time. In addition, the background noise baseline drift trend is recorded to ensure that anomaly identification is not affected by environmental electrical disturbances. To ensure spatial consistency, the central axis of each electrode pair is symmetrical with the aforementioned spectral acquisition path, and the time stamp accuracy of synchronous recording is less than 1 nanosecond, ensuring a complete correspondence between the spectrum and the electrical signal.

[0067] After each droplet passes through the monitoring area, its spectral data and microcurrent data together form a joint feature vector. Spectral features include the intensity ratio between the NO excitation band (226 nm) and the NO2 excitation band (247 nm), the peak change rate of the NO spectral line, and the spectral fluctuation period; microcurrent features include the slope of the current rise time, the peak duration, and the baseline recovery rate. These parameters are standardized and then input into the established micro-discharge prior feature model. This model is derived from typical micro-plasma excitation paths identified in numerous previous experiments and has clear physical thresholds. Specifically, the identification criteria are: when the ratio of NO to NO2 luminescence intensity is greater than 3.5 times within 1 microsecond, and the microcurrent peak value is greater than 0.6 microamps, and the current slope is greater than 3.2 microamps / microsecond, it is determined to be a micro-plasma precursor state. To improve robustness, a dual-threshold cross-validation mechanism is introduced: if two consecutive droplet samples both meet the criteria and their time interval is less than 15 microseconds, they are marked as high-confidence precursor state events. The spatial coordinates, timestamps, and feature values ​​of precursor events are stored in the monitoring database to support subsequent risk modeling.

[0068] All precursor events are constructed as a 3D spatial map, with each event acting as a localizable spatial charge perturbation point, and its corresponding risk score is superimposed. The risk score is calculated by weighting the spectral fluctuation amplitude, current slope, trigger frequency, and overlap with the aggregation threshold range. The maximum risk score is set to 1, scores below 0.3 are considered noise, 0.3 to 0.7 are considered suspicious events, and scores above 0.7 are marked as high-risk trigger points. The system generates a real-time risk map every 10 milliseconds and links it with the sprayer electric field control program. When a spray area is marked as a high-risk point for two consecutive cycles, the spray electric field intensity is reduced by 20% in real time, the electric field frequency is adjusted from 100 kHz to 70 kHz, and the spray particle size control device reduces the liquid supply rate by 3%. After each response behavior, a feedback scan is performed 10 milliseconds after its completion to check if any risk points have been eliminated. If high-risk points still exist, dynamic closed-loop control is executed for two consecutive rounds until all high-risk markers are eliminated. Simultaneously, all events are stored for further counterfactual playback and evolutionary path learning.

[0069] Based on the output of the dynamic early warning chain, the counterfactual replay chain is invoked to simulate the charge evolution path, reconstruct the damage process of the ion intercalation sequence, generate the structural instability mapping, and construct the particle size-dependent suppression strategy boundary.

[0070] To achieve a closed-loop control mechanism from microplasma precursor state identification to macroscopic structural risk regulation, it is necessary to reversibly reconstruct the droplet evolution path under charge perturbation and construct a particle size-dependent instability suppression boundary based on actual structural anomaly information. This is implemented through the following steps:

[0071] Droplet samples marked as Level 1 risk areas within the spray channel were selected, and their picosecond-level spectral data, current pulse sequences, flight time coordinates, electric field intensity distribution, and particle size information were extracted. Using the spatiotemporal trajectory of each droplet as the main axis, charge density variation curves were constructed within intervals of 100 microseconds before and 50 microseconds after time. The original data were normalized using a constant-step resampling method to remove abrupt anomalies caused by discharge, resulting in a smooth trend line of charge concentration under natural evolution. Based on this, low-risk droplets with similar particle sizes that did not experience discharge events within the same time period were used as control samples, and a least-squares fitting model of the charge flux gradient was established. The spatial diffusion path of charge that the current sample might experience before a discharge event was calculated using the fitting residuals, forming a "counterfactual charge channel map." This map reflects the equipotential distribution of surface charge polarity changes, migration rates, and spatial aggregation intensity of droplets without triggering discharge, and can be used to identify the physical offset range caused by actual discharge behavior to the charge evolution chain.

[0072] At each spatial node where a shift is confirmed, the metal ion charge state value and the preset lattice intercalation position at the adjacent time point are extracted. Ni in the droplet... 2 +、Co 2+ Mn 2+ Three ions were assigned a target intercalation sequence according to a standard ratio (Ni enters octahedral sites, Co enters edge sites, and Mn fills facet sites). The ion offset index was calculated by measuring the rate of change of the electric field direction at each node and the deflection angle of the ion migration path. When the offset index was greater than 0.65, the intercalation sequence at that site was considered disturbed. Starting from the droplet centroid, the three-dimensional spatial coordinates of all abnormal sites were traced to construct an "ion intercalation failure trajectory chain," and multiple failure points were clustered into a structurally unstable block using a thermal merging algorithm. Subsequently, a "structural instability thermogram" was constructed with spray time as the vertical axis, droplet size as the horizontal axis, and intercalation failure intensity as the gamut density. This figure reveals that large-diameter droplets are more prone to early intercalation sequence collapse under charge disordered conditions, and the failure path density is significantly higher than that of small-diameter droplets, demonstrating a high correlation between droplet size and structural stability. In existing technologies, defect distribution is usually analyzed by analyzing the crystal diffraction pattern of the sintered material. This method, however, achieves the prediction and mapping of defect locations for the first time during the precursor generation stage by instantly reconstructing the charge path and intercalation process.

[0073] Statistical regression was performed on all particle size ranges in the thermogram to calculate the intercalation failure frequency, average path length, and failure duration for each particle size range. The results showed that for droplets with a particle size greater than 6 micrometers, the instability frequency of the intercalation sequence exceeded 80%, while this value dropped to less than 20% for droplets smaller than 3 micrometers. Based on this data, a "structural instability risk function curve" was constructed, with failure intensity as the ordinate and particle size as the abscissa; the inflection point of the curve represents the threshold for structural inhibition. To achieve process control, the critical particle size was set at 5.2 micrometers, and the following three intervention measures were implemented to stabilize the ion intercalation sequence: first, the spray pressure was controlled between 0.25 MPa and 0.28 MPa to reduce the peak width of the particle size distribution through a high pressure differential; second, the length of the transition gradient zone was increased to 50 mm in the initial pyrolysis stage to prolong the droplet residence time in the intermediate temperature zone and reduce its internal temperature gradient; third, the dynamic adjustment range of the electric field frequency was expanded from the original 120 kHz to 90-130 kHz to regulate the synergy of ion diffusion. The aforementioned control measures form a "structural inhibition regulation boundary map" with particle size as the core variable. This map can be used for the process co-design of atomization equipment, thermal field devices, and charge control paths to achieve closed-loop control throughout the entire process, from risk identification, path restoration, structural prediction to parameter intervention.

[0074] Based on the suppression strategy boundary, an adaptive doped migration modulator is generated, and a linkage control curve between electric field strength, frequency, pulse width and spray rate is constructed to form a multi-parameter coupled energy balance trajectory.

[0075] To ensure that the spatial distribution and migration behavior of metal dopant ions during spray pyrolysis meet the requirements of lattice-ordered intercalation, a dopant migration control mechanism needs to be constructed under the boundary constraints of the particle size suppression strategy. Specifically, this is achieved by adjusting the linkage between the electric field parameters and the spray process parameters to form an energy distribution equilibrium trajectory that can respond to different particle sizes and risk states. The implementation process is as follows:

[0076] Based on the obtained particle size-dependent structural instability boundary, a droplet size of 5.2 micrometers was set as the critical value. Samples with a particle size smaller than this value were labeled as low-intercalation-risk droplets, and samples with a particle size larger than this value were labeled as high-intercalation-risk droplets. For a typical doping system of ternary cathode precursor materials for lithium-ion batteries, Ni was selected... 2 +、Co 2+ and Mn 2+ Three metal ions were selected as dopants, and their lattice migration sequences were defined as follows: Ni 2 + preferentially intercalates at octahedral sites to form crystal nuclei, Co 2+ Diffusion to the edge sites to build the lattice framework, Mn 2+ A symmetry repair region is formed by filling in the outer layer. Under this doping sequence, the doping behavior is highly sensitive to the direction of the electric field, the pyrolysis rate, and the droplet evaporation rate. To achieve dynamic control of doping migration behavior, four key control parameters were established: electric field strength (kilovolts per centimeter), electric field frequency (kilohertz), pulse width (microseconds), and spray rate (milliliters per minute). Each parameter was set with an adjustable range: electric field strength from 1.6 to 2.5 kV / cm; frequency from 60 to 140 kHz; pulse width from 2 to 6 microseconds; and spray rate from 2.0 to 3.5 ml per minute. To verify the control effect of these four variables on the doping path, representative samples were selected in the particle size range from 2 to 8 micrometers, and inversion simulation and migration migration tests were conducted to confirm that the above parameters are the decisive variables for doping behavior.

[0077] During the experiment, it was found that when the droplet size was in the high-risk region (particle size ≥ 6 micrometers), if the electric field strength was maintained above 2.1 kV / cm, and the pulse width was extended to 5 microseconds, while the spray rate was reduced to 2.2 ml / min, Ni 2 The embedding path offset angle decreased from 6.5° to 2.8°, demonstrating a significant path repair effect. To achieve automated parameter adjustment, Ni... 2 +、Co 2+ and Mn 2+Using migration stability as the target response quantity, surface response models were established between the migration offset angle and process parameters. Based on the principle of minimum offset angle, the optimal parameter combination was derived in reverse. Through numerical fitting, the response relationship between the four parameters was constructed as a "doping migration linkage control curve". In this curve, each set of parameters corresponds to the optimal control point of the doping path within a particle size range. With electric field strength as the main variable, the other three parameters were set to have complementary adjustment capabilities when the electric field strength increases: increasing the electric field strength can alleviate the diffusion hysteresis caused by the increase in particle size, but the spray rate needs to be reduced simultaneously to avoid ion segregation; increasing the frequency increases the penetration rate of the applied field, which is beneficial for small particle size samples to form a synchronous diffusion state of ions; adjusting the pulse width plays a balancing role on the linear response of the migration rate. After establishing this curve, it was loaded into the control loop in the form of a data table, enabling the equipment to dynamically call the corresponding control parameter combination according to the real-time particle size measurement results, charge density, and doping offset angle measurement values, so as to achieve continuous online adjustment.

[0078] In the actual spray pyrolysis production process, real-time particle size detection is performed synchronously using a high-speed time-of-flight meter and laser scattering method, while charge density is updated by a charge induction acquisition probe at a frequency of 10 microseconds. Before each droplet sample enters the pyrolysis zone, its particle size, charge state, velocity, and evaporation rate are jointly analyzed to generate a parameter vector containing predictions of doping behavior. The control command unit compares this vector with the "doping migration linkage control curve," immediately matches the current optimal parameter range, and transmits the matched value to the electric field drive source, frequency generator, electrode on / off control device, and spray supply pump. Each device completes parameter updates within a control cycle with a delay of no more than 5 milliseconds, ensuring energy modulation is completed before the droplets reach the pyrolysis zone. This process is continuously executed, forming a dynamically adjustable "energy balance trajectory" throughout the spray path. This trajectory is based on the energy changes contributed by each parameter per unit time, superimposed to form a total energy distribution curve. In the high-risk particle size range, the curve shows enhanced electric field energy and reduced thermal coupling, while in the low-risk particle size range, it exhibits a dynamic trend of spray energy dominance and enhanced pulse width control. Trajectory stability is directly mapped to the consistency of dopant migration path and the uniformity of ion diffusion. Precursors formed under this coupled trajectory constraint exhibit advantages such as uniform grain size, balanced dopant distribution, and low structural stress concentration in their subsequent calcination products.

[0079] Under the constraint of energy balance trajectory, phase conjugate charge pumping, acoustic flow micro-vortex traction and reversible time grid peak staggering are performed. Energy redistribution is achieved through online migration of residual density, and a closed-loop dynamic control system is constructed to suppress the formation of partial discharge chains.

[0080] To effectively suppress the partial discharge chain phenomenon caused by droplet charge imbalance during spray pyrolysis, charge pumping, acoustic micro-vortex traction, time grating peak shifting, energy residual migration, and closed-loop control must be implemented sequentially under the aforementioned energy balance trajectory constraints to achieve the control objectives of dynamic energy redistribution and stable lattice growth path throughout the entire process. Specific implementation methods are as follows:

[0081] In the spray pyrolysis path, localized areas of concentrated charge formed by droplets due to increased particle size or insufficient atomization can easily exceed the uniformity threshold in terms of electric field distribution, triggering transient micro-discharges. To avoid such localized energy surges, this embodiment arranges multiple charge excitation electrodes with phase control capabilities on both sides of the pyrolysis path. A matching relationship is established between a preset charge frequency and the droplet flight period to form a reverse conjugate excitation wave. When monitoring detects that the charge density per unit volume on the droplet surface exceeds 2 picocoulombs per cubic micrometer and the charge distribution exhibits a unidirectional polarization trend, the reverse electrode instantly triggers a conjugate excitation pulse, forming a phase-reversed electric field disturbance wave. This disturbance wave cancels out the droplet charge distribution, causing the charge density to disperse and expand towards the axis, driving the high-density charge originally concentrated at the boundary to migrate to the low-charge region. This alleviates the local electric field intensity in the charge concentration area, achieving cluster de-aggregation and energy dissipation, and reducing the potential discharge risk.

[0082] Acoustic flow traction utilizes several ultrasonic excitation devices uniformly distributed in the central region of the spray channel to create a spatial standing wave with a frequency controlled between 650 kHz and 850 kHz. As the droplet crosses the sound pressure zone, the ultrasonically induced interlaced vortex field forms a symmetrical rotating structure around the droplet. This micro-vortex couples the internal and external flow fields of the droplet, enhancing boundary layer disturbance and promoting the diffusion of doped ions from the droplet surface towards the droplet nucleus. The rotation direction, vortex magnitude, and number of vortex nuclei of this acoustic vortex field can be dynamically adjusted based on the real-time droplet size and velocity, ensuring the stability of the vortex structure at different flight stages. Acoustic vortex guidance not only improves the uniform distribution of metal ions but also breaks the original static heat transfer path, transforming the droplet temperature distribution from high at the center and low at the edges to an axial transition type. This is beneficial for the symmetrical growth of crystal nuclei during subsequent pyrolysis and enhances the steady-state continuity of the ordered grain intercalation process.

[0083] The pyrolysis path is divided into uniform time grids of 8 mm in length along the flight direction. A droplet parameter detection unit is installed in each grid to monitor droplet size, temperature change rate, and energy density in real time. If droplets in a certain section exhibit a concentrated high-energy state, for example, an energy density exceeding 90 joules per cubic millimeter, a staggered drive strategy is triggered. Specifically, the spray carrier gas velocity in this area is adjusted, decreasing by 0.8 m / s in the high-energy grid to prolong droplet residence time; simultaneously, the gas velocity in the grids before and after it is increased to a normal velocity of 0.5 m / s, causing droplets to pass through these areas earlier or later. This staggered control staggers the energy release periods of multiple high-energy droplets, preventing energy peaks from synchronously superimposing in space, thereby suppressing the short-term electric field superposition amplification effect and reducing the probability of micro-discharge triggering.

[0084] Although the above steps have effectively controlled most of the abnormal energy distribution, temporary residual energy accumulation zones may still occur locally due to charge rebound or thermal inertia. This step involves scanning the real-time energy density distribution along the pyrolysis path point by point to identify regions with energy density exceeding 25% of the average value per unit space and to determine whether a persistent residual has formed. If this value does not decrease within three consecutive cycles, a spatial migration mechanism is activated: by adjusting the difference in excitation frequencies between the left and right electrodes, spatial electric field polarization is created, causing the target droplet to drift laterally from the mainstream path at an angle between 3° and 7°. During the drift, the droplet migrates from the high-energy channel into a lower-energy-density section, while the acoustic vortex structure rotates synchronously in the direction of action, exporting the residual energy from the original region as vortex kinetic energy and diffusing it into the surrounding environment, thus completing the energy redistribution operation. This method maintains the energy density of each flight path in a relatively balanced state, preventing the re-accumulation of micro-local high-energy clusters and the risk of secondary discharge.

[0085] By comparing the charge density changes generated by phase-conjugate charge pumping, the ion distribution trajectory guided by acoustic micro-vortices, the energy release curve caused by time-shifting peaks, and the residual migration repair path with the dynamic data of the energy balance trajectory, a feedback mapping table containing five coupling parameters is established. After each control operation is completed, its result becomes the input reference for the next operation, forming a strongly correlated recursive chain. When an energy control imbalance trend occurs at any stage (e.g., migration amplitude is insufficient, the shifting peak interval is too short, or the direction of the acoustic vortex is inconsistent with the main diffusion direction), the system adjusts the previous control parameters in real time according to the mapping table, achieving omnidirectional closed-loop intervention from the front end to the end of the path. This collaborative control system differs from the existing technology strategy that only operates at a fixed spray rate and voltage. It achieves high-resolution stable control driven by multi-dimensional information throughout the entire process, effectively avoiding the cascading evolution of the micro-discharge chain during spray pyrolysis, and significantly improving the stability of the precursor structure and the uniformity of doping.

[0086] This invention achieves real-time identification and dynamic early warning of the discharge precursor state by constructing a charge spatiotemporal reference and a multi-scale potential inversion mechanism; it identifies the key perturbation region for crystal nucleus growth through counterfactual path backtracking and structural instability mapping; and then, guided by the energy coupling trajectory, it achieves the directional migration and redistribution of residual energy through charge pumping, micro-vortex traction, and time staggering, ultimately constructing a stable, closed-loop spray pyrolysis control environment. This not only effectively suppresses the formation of amorphous clusters and improves doping uniformity and crystal phase purity, but also significantly enhances the controllability of the ternary precursor particle size distribution and structural stability, providing an advanced, engineering-feasible process route for the large-scale preparation of high-performance lithium-ion battery cathode materials.

[0087] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for preparing pure-phase, doped ternary precursors using a spray pyrolysis method based on a nitrate system, characterized in that, Includes the following steps: A time baseline and electrothermal flow field tomography network were established to continuously sample the droplet charge distribution in the spray area, construct a charge flux spectrum, extract the micro-discharge prior fingerprint, and form a charge spatiotemporal reference. Based on the charge spatiotemporal reference, phase difference mapping is performed, and the charge potential energy distribution is analyzed by Laplace-Poisson inversion to determine the charge enrichment nuclei and calculate the aggregation trigger threshold. Based on the aggregation triggering threshold, a picosecond-level spectral monitoring mechanism is introduced to collect the nitrogen oxide luminescence intensity ratio and microcurrent pulse sequence, identify the microplasma precursor state, and establish a dynamic early warning chain. Based on the output of the dynamic early warning chain, the counterfactual replay chain is invoked to simulate the charge evolution path, reconstruct the ion intercalation failure process, generate the structural instability mapping, and construct the particle size-dependent suppression strategy boundary. Based on the suppression strategy boundary, a doped migration modulator is generated, and a linkage control curve of electric field strength, frequency, pulse width and spray rate is constructed to form an energy balance trajectory. Under the constraint of energy balance trajectory, charge pumping, acoustic flow traction and time grid driving are performed, and energy redistribution is achieved through online migration of residual density. A closed-loop dynamic control system is constructed to suppress partial discharge chains.

2. The method for preparing pure-phase, doped ternary precursors by spray pyrolysis based on a nitrate system according to claim 1, characterized in that, The steps for forming a charge-spacetime reference are as follows: After establishing a unified time baseline and electrothermal flow field tomography network, multiple time triggering devices are equidistantly deployed along the spray area path to synchronously record the droplet ejection time, thus constructing a three-in-one tomographic observation framework integrating time, electric field, and thermal field. Based on the established time and space reference, the droplet charge is sampled in segments using an electrostatic deflection trapping device, and continuous recording of the droplet charge is achieved by combining it with a dual-channel time-of-flight measurement device. Based on continuous sampling results, a droplet charge flux density map is constructed, high-risk charge enrichment regions are extracted, and a set of micro-discharge prior fingerprint features is labeled. Under the constraint of a unified time baseline, and combined with the droplet flight trajectory, a three-dimensional mapping relationship of space, charge, and time is established to generate a charge spatiotemporal reference atlas.

3. The method for preparing pure-phase, doped ternary precursors by spray pyrolysis based on a nitrate system according to claim 2, characterized in that, The reunion trigger threshold calculation process is as follows: After establishing a charge spatiotemporal reference, the spray path is divided into multiple main-scale segments and further divided into sub-scale layers. Multiple charge dynamic points are extracted, the charge phase difference is calculated, and a phase difference distribution map is formed. Based on the phase difference distribution map, the Laplace-Poisson inversion method is used to calculate the potential field structure, construct the potential gradient distribution map between spatial nodes, and form a complete potential field. In the potential field, identify potential extreme points that satisfy the extreme value, the threshold of charge flux change slope and time coherence as charge enrichment nuclei; An observation region is constructed around the charge-rich nucleus, the local energy density is calculated, and the aggregation determination factor is calculated based on the ratio of the electrostatic force between droplets to the centrifugal force, thus defining the aggregation trigger threshold of the spray channel.

4. The method for preparing pure-phase, doped ternary precursors by spray pyrolysis based on a nitrate system according to claim 3, characterized in that, The process of establishing a dynamic early warning chain is as follows: After calculating the aggregation trigger threshold, four regions with the highest charge enrichment and energy density were selected as excitation and acquisition anchor points, and high-resolution optical acquisition channels and current acquisition channels were set up. Nitrogen-containing intermediate species in droplets were excited using a picosecond-level pulse excitation source, and the ratio of NO to NO2 luminescence intensity was collected. At the same time, the microcurrent pulse characteristics when the droplet passed through the electrode region were recorded to obtain synchronous spectral and electrical signal data. The collected spectral and current features are standardized and input into the micro-discharge prior feature model for identification, and a micro-plasma precursor event map is constructed to generate a dynamic early warning chain with timestamps and spatial coordinates. Based on the continuity of high-risk trigger points in time and space, the spray electric field intensity, frequency, and liquid supply rate are adjusted in real time to form a closed-loop dynamic response mechanism for electrical discharge risk.

5. The method for preparing pure-phase, doped ternary precursors by spray pyrolysis based on a nitrate system according to claim 4, characterized in that, The criteria for identifying microplasma precursor events include that the ratio of the luminescence intensity of NO to NO2 is greater than three times within a preset time, and the corresponding microcurrent pulse peak exceeds a set current threshold and has a rise edge slope exceeding a predetermined rate. When two consecutive droplet samples that meet the above characteristics appear within a limited time interval, they are marked as high-confidence precursor events.

6. The method for preparing pure-phase, doped ternary precursors by spray pyrolysis based on a nitrate system according to claim 4, characterized in that, The process of constructing the suppression policy boundary is as follows: Based on the output results of the dynamic early warning chain, droplet samples marked as first-level risk areas in the spray channel were selected, and spectral data, current sequences, flight time, electric field strength and particle size information were extracted to construct charge density change curves and form counterfactual charge channel maps. At spatial nodes with offsets, the charge state of metal ions and lattice insertion positions are extracted, the ion offset index is calculated and the coordinates of abnormal sites are tracked, the ion insertion failure trajectory chain is constructed and a structural instability thermogram is formed. Statistical regression was performed on droplet samples of different sizes to calculate the frequency and duration of embedding failure, establish structural instability risk function curves and determine the particle size inhibition boundary; Based on the suppression boundary, the spray pressure, temperature range and electric field frequency are linked and controlled to form a particle size-dependent structure suppression control boundary map, thus achieving closed-loop control throughout the entire process.

7. The method for preparing pure-phase, doped ternary precursors by spray pyrolysis based on a nitrate system according to claim 6, characterized in that, The formation process of the energy balance trajectory is as follows: Based on the particle size-dependent structural instability boundary, a critical droplet size value is set to classify droplets with high insertion risk and low insertion risk, and four control parameters are established: electric field strength, electric field frequency, pulse width and spray rate. By constructing a surface response model between the doping migration offset angle and four control parameters, a doping migration linkage control curve is established, and the curve is loaded into the control loop to achieve automatic matching and updating of parameter combinations. Before the droplets enter the pyrolysis zone, a parameter vector is generated based on the real-time particle size, charge state, velocity, and evaporation rate. The optimal parameter combination corresponding to the doping migration linkage control curve is then invoked to construct a dynamically adjustable energy balance trajectory.

8. The method for preparing pure-phase, doped ternary precursors by spray pyrolysis based on a nitrate system according to claim 7, characterized in that, Under the constraint of energy balance trajectory, charge pumping, acoustic current traction, and time grid driving are performed, and energy redistribution is achieved by combining online migration of residual density. The steps to construct a closed-loop dynamic control system are as follows: Under the constraint of energy balance trajectory, a phase control electrode is set up, and a phase conjugate electric field pulse is triggered based on the change of droplet surface charge density to realize the spatial redistribution of charge density; An ultrasonic excitation device is placed in the flight path of the droplets to stimulate a rotating vortex that pulls the boundary layer ions of the droplets to diffuse toward the droplet nucleus, thereby adjusting the uniformity of ion distribution. The flight path is divided into uniform time grid regions, and a staggered driving strategy is implemented in high-energy-density sections to adjust the droplet passage time and avoid energy concentration and superposition. Identify the energy density residual region, perform spatial migration operation to make high-energy droplets drift laterally to the low-energy region and complete energy diffusion; Establish a coupling parameter feedback mapping table, and recursively adjust subsequent control commands based on the results of previous control, thus constructing a closed-loop dynamic intervention mechanism throughout the entire process.

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