Oxygen-enriched vacancy multi-surface defect nickel oxide positive electrode material for thermal battery and preparation method thereof

Abstract

The application discloses an oxygen-enriched vacancy multi-surface defect nickel oxide positive electrode material for thermal batteries and a preparation method. The oxygen-enriched vacancy multi-surface defect nickel oxide positive electrode material is prepared by a ball milling defect-inducing, surface charge regulating, atomization quenching, granulation, powder mixing and drying and crushing process. Firstly, the oxygen vacancy design is used to improve the electronic structure of the nickel oxide material, reduce the diffusion energy barrier of ions and improve the thermal strain resistance of the material. Secondly, the introduction of multi-dimensional metal conductive agents is used to significantly improve the conductivity of the composite material, reduce the internal resistance of the battery and improve the utilization rate of the positive electrode material. Finally, the design of various defects such as surface cracks, pits and holes can promote the adhesion of the conductive agent and the additive, is beneficial to the flow penetration and mutual wetting of the alkali metal additive and the electrolyte during high-temperature discharge, accelerates the electrochemical reaction and optimizes the electrochemical performance of the oxygen-enriched vacancy multi-surface defect nickel oxide as the positive electrode material of the battery.

Description

Technical Field

[0001] This invention belongs to the field of chemical power source thermal battery technology, specifically relating to an oxygen-rich nickel oxide cathode material with multiple surface defects and vacancies for thermal batteries and its preparation method. Background Technology

[0002] Thermal batteries are primary storage batteries activated by electrical or mechanical signals, using high-temperature molten salt as the electrolyte. Due to their high output power, long storage life, rapid activation, and excellent environmental adaptability, thermal batteries have become one of the ideal chemical power sources for advanced military weapons such as missiles, artillery, and fuses. In recent years, the use of high-melting-point (>600℃) lithium-boron alloys as the negative electrode material has solved the problem of conventional lithium sheet melting and flowing at high temperatures, greatly improving the high-current discharge capacity and safety reliability of thermal batteries. Simultaneously, the development and application of novel ternary electrolytes (LiCl-LiBr-LiF) with high conductivity and chemical stability have also promoted the improvement of thermal battery discharge capacity. However, the positive electrode material has become the main factor limiting further improvements in the electrical performance of thermal batteries.

[0003] Currently, the main cathode materials for thermal batteries are pyrite-type sulfides, such as FeS2, CoS2, and NiS2. CN201910941658.5 reported a method for preparing nickel-cobalt sulfide cathode materials using an ethanol hydrothermal method. However, firstly, the theoretical specific capacity of sulfide cathode materials is relatively low and their thermal stability is poor. Decomposition at high temperatures leads to a further decrease in battery capacity, material utilization, and battery life. Secondly, the decomposition of sulfide materials and the volatilization of sulfur generated during discharge can cause voltage fluctuations and generate electrical noise. In severe cases, this can lead to increased internal pressure in the battery or even thermal battery explosion, causing safety problems. CN202310897631.7 reports a method for preparing sulfide cathode materials using a high-temperature sulfidation-high-temperature desulfurization process. However, this method firstly uses sulfur or sublimed sulfur, which has explosive properties, as a sulfiding agent during the synthesis process, resulting in a high risk factor. Furthermore, due to the multiple valences of transition metals such as iron, cobalt, and nickel, coupled with the strong oxidizing and chain-polymerizing properties of sulfur, transition metal sulfides generally contain a large number of stable intermediate transition states, leading to difficulties in synthesizing high-purity single-phase materials and complex discharge mechanisms. Therefore, developing cathode materials with high theoretical specific capacity, long service life, high thermal stability, simple electrochemical reaction, and safe and convenient synthesis processes has become one of the future development directions for thermal batteries.

[0004] Nickel oxide possesses high theoretical capacity and good thermal stability, making it suitable as a cathode material for thermal batteries. However, the generally high ion diffusion barrier and low intrinsic conductivity of oxides limit their widespread application. To address the high ion diffusion barrier, CN202411329639.4 discloses a lithium-rich manganese-based cathode material with controllable oxygen vacancies; oxygen vacancies are obtained through ultra-high temperature calcination, thus lowering the ion diffusion barrier. However, this method relies on a high-temperature environment, consumes a lot of energy, cannot simultaneously achieve surface defect design during processing, and does not significantly improve the material's conductivity. CN202411224559.2 discloses a NiFe-LDH@E-PBA composite electrocatalyst rich in oxygen vacancies; oxygen vacancies and defects are introduced through electrodeposition combined with alkaline etching, reducing the ion diffusion barrier. However, this method has a complex preparation process, and the alkaline environment limits the types of materials that can be used. Furthermore, CN201811059263.4 improves ion transport by introducing an appropriate amount of solid electrolyte salt into nickel chloride cathode materials through grinding. This method may not achieve complete uniform mixing of lightweight raw materials or raw materials with large differences in weight during the grinding and mixing process, and may easily generate dust hazards.

[0005] To address the low intrinsic conductivity, CN113488623B effectively improved the conductivity of fluoride cathode materials by introducing graphene oxide. However, carbonaceous conductive agents are prone to oxidation at high temperatures, generating CO2 gas, which affects battery safety and reliability. CN202210151776.8 reported a method for loading silver spheres onto carbon cloth through in-situ growth, but the solvothermal reaction depends on a high-temperature and high-pressure environment, making the process complex and time-consuming. CN201010243716.6 disclosed a silver-doped nano-nickel hydroxide cathode material, in which silver does not exist in elemental form, resulting in poor thermal stability and unsuitability for the extreme high-temperature environment of thermal batteries. Furthermore, Zhang et al. (Zhang, X, Zhu, Y, Bruck, AM, et al. EnergyStorage Materials, 2019, 19: 439-445.) pointed out that due to the small size of nanoparticles and the short interaction distance of van der Waals forces between particles, severe mutual adsorption and aggregation easily occur between particles. For nanoscale metallic conductive additives, conventional material composite techniques, such as high-energy ball milling and mechanical stirring, are prone to uneven dispersion. Uneven conductive agent distribution leads to localized over-reaction and under-reaction of the active material during discharge. Furthermore, achieving uniform loading and tight composite of the nickel oxide support and the metallic conductive agent remains a challenge. Summary of the Invention

[0006] This invention addresses the problems of poor thermal stability, low discharge specific capacity, low material utilization, and short battery life of current thermal battery sulfide materials by providing an oxygen-vacancy-rich nickel oxide cathode material with multiple surface defects and a preparation method. The nickel oxide provided by this invention exhibits high thermal stability and theoretical specific capacity. High-energy ball milling introduces abundant oxygen vacancies and multiple surface defects to improve the electronic structure, thermal strain resistance, additive adhesion, and electrochemical activity of the nickel oxide material. Simultaneously, a novel material composite process is designed to achieve multi-dimensional modification of the metal conductive agent to optimize the conductivity of the composite material, reduce battery internal resistance, and improve battery capacity output and quality reliability. Finally, the introduction and embedding of alkali metal additives in the surface defects improves high-temperature conductivity and promotes wettability and penetration with molten salt electrolytes.

[0007] This invention prepares an oxygen-vacancy-rich nickel oxide cathode material with multiple surface defects through a process of ball milling-induced defects, surface charge regulation, atomization quenching granulation, and powder mixing and drying. This oxygen-vacancy-rich nickel oxide cathode material has a high melting point and high thermal stability, exhibiting no significant decomposition under the extreme high-temperature environment of thermal batteries, thus avoiding the impact of thermal decomposition impurities and gas generation on the stability and safety of the battery system. Secondly, the nickel oxide cathode material has a significantly higher theoretical specific capacity than sulfide cathode materials, which can improve the capacity output and service life of thermal batteries. Furthermore, the electrochemical reaction of the nickel oxide cathode material is simple, and the discharge products are highly conductive elemental metals beneficial to the battery system. Then, the design of oxygen vacancies and surface defects can improve the electronic structure of the nickel oxide material, reduce the diffusion barrier of ions, and simultaneously improve the thermal strain resistance and electrochemical activity of the nickel oxide cathode material. It also provides filling and insertion sites and space for multi-dimensional metal conductive agents, optimizing the electrochemical performance as a battery cathode material. Simultaneously, the introduction of multi-dimensional metallic conductive agents significantly improves the electrical conductivity of the composite material, reduces electron transport barriers, decreases battery internal resistance, and enhances the utilization rate of the cathode material. Furthermore, the introduction and embedding of alkali metal additives into surface defects improves high-temperature conductivity and promotes wettability and penetration with molten salt electrolytes. Finally, the surface charge regulation-atomization quenching granulation-mixing drying and pulverization process achieves uniform and tight bonding of the composite material, reduces dust and other hazards, improves the production environment, and reduces occupational hazards.

[0008] Specifically, the objective of this invention is achieved through the following technical solutions:

[0009] This invention relates to a nickel oxide cathode material with oxygen-vacancy-rich surfaces and multiple defects for thermal batteries. The cathode material comprises a multi-dimensional metal conductive agent and an alkali metal additive dispersed and loaded onto the surface of a nickel oxide carrier with oxygen-vacancy-rich surfaces and multiple defects. The dispersion involves the multi-dimensional metal conductive agent preferentially filling and embedding within surface defect grooves, while the alkali metal additive is adhered and dispersed on the outer surface of the nickel oxide particles. The multi-dimensional metal conductive agent is a combination of two or more of the following: 0-dimensional metal nanoparticles, 1-dimensional metal nanowires, 2-dimensional metal nanosheets, and 3-dimensional metal nanoblocks. This nickel oxide cathode material is prepared using a process of ball milling to induce defects, surface charge regulation, atomization quenching granulation, and powder mixing, drying, and pulverization. The resulting nickel oxide cathode material is rich in oxygen vacancies, with the multi-dimensional metal conductive agent and alkali metal additive filling and adhering to various defects such as cracks, pits, and pores on the nickel oxide surface.

[0010] In the cathode material system of this invention, oxygen-rich vacancy-rich nickel oxide with multiple surface defects serves as the active material, directly participating in the electrochemical reaction during the discharge process of the thermal battery. The multidimensional metal conductive agent, acting as a conductivity-optimizing modifier, does not directly participate in the electrochemical reaction but significantly improves the material's conductivity and reduces the electron transport barrier. The alkali metal additive acts as an electrolyte in the electrochemical reaction, improving the high-temperature conductivity of the cathode material and promoting the wettability and penetration of molten salt electrolytes with similar compositions. This results in reduced internal resistance, increased specific capacity, improved utilization of the active material, and the absence of electrical noise and voltage fluctuations in the thermal battery.

[0011] As one implementation scheme, nickel oxide crystals possess abundant oxygen vacancies within their interiors, while their surfaces exhibit one or more defects such as cracks, pits, and pores, providing filling and embedding sites and spaces for multidimensional metallic conductive agents. The oxygen vacancy design improves the electronic structure of nickel oxide materials and lowers the ion diffusion barrier. Through the design of various surface defects such as cracks, pits, and pores, filling and embedding sites and spaces can be provided for multidimensional metallic conductive agents, promoting the adhesion of conductive agents and additives. This facilitates the melting and flow of alkali metal additives and electrolytes during high-temperature discharge, accelerating electrochemical reactions.

[0012] As one implementation scheme, the multidimensional metal conductive agent is a combination of two or more of the following: 0-dimensional metal nanoparticles, 1-dimensional metal nanowires, 2-dimensional metal nanosheets, and 3-dimensional metal nanoblocks. Specifically, 0-dimensional metal nanoparticles are small-diameter metal particles with a particle size of 25-50 nanometers; 1-dimensional metal nanowires are metal nanowires with a diameter less than 50 nanometers and a length greater than 1 micrometer, possessing a high aspect ratio; 2-dimensional metal nanosheets are metal nanosheets with a thickness at the nanometer level and a lateral dimension that may reach hundreds of nanometers or even larger; and 3-dimensional metal nanoblocks are metal nanospheres or other irregularly shaped metal nanoblocks with larger dimensions. The metal species in the multidimensional metal conductive agent are one or more combinations of gold, silver, copper, nickel, aluminum, magnesium, and zinc. Ordinary single-dimensional conductive agents (such as single-dimensional carbon black or metal powder) may face problems such as incomplete conductive networks, poor interfacial contact, or oxidation at high temperatures. The combination of multidimensional metal conductive agents, with their complementary properties, can construct a more stable three-dimensional conductive network. Zero-dimensional metal nanoparticles can effectively fill the gaps between cathode material particles, reducing contact resistance; one-dimensional metal nanowires bridge active material particles, forming a long-range conductive framework; two-dimensional metal nanosheets provide a surface contact conductive layer, enhancing interfacial electron transfer; and three-dimensional metal nanoblocks provide stable conductive structural anchors. Therefore, multi-dimensional metal conductive agents have a greater advantage in improving conductivity.

[0013] As one embodiment, the alkali metal additive is one or more of lithium carbonate, lithium chloride, lithium fluoride, lithium bromide, potassium iodide, potassium chloride, and calcium chloride. Preferably, the alkali metal additive is of the same or similar type as the molten salt electrolyte, which improves the high-temperature conductivity of the cathode material while promoting mutual wetting with the molten salt electrolyte.

[0014] In one implementation scheme, the mass percentages of the oxygen-vacancy-rich multi-surface-defect nickel oxide support, multi-dimensional metal conductive agent, and alkali metal additive in the nickel oxide cathode material are 75-95%, 2-10%, and 3-15%, respectively. Adding an appropriate amount of multi-dimensional metal conductive agent can significantly improve the conductivity of the composite material, reduce the electron transport barrier, and decrease the battery's internal resistance. When the addition amount is less than 2%, it is too small to improve conductivity; when the addition amount is greater than 10%, it leads to a decrease in the proportion of active material, affecting the discharge specific capacity of the cathode material. Pre-filling with alkali metal additives can improve the high-temperature conductivity of the cathode material and promote the wettability and penetration ability of molten salt electrolytes with similar compositions. When the addition amount is less than 3%, it is too small to have a significant improvement effect; when the addition amount is greater than 15%, it leads to a decrease in the proportion of active material, affecting the discharge specific capacity of the cathode material.

[0015] As one implementation, the nickel oxide cathode material has an initial decomposition temperature of 650-800℃, uniform particle size, and a particle size of less than 100μm. This material exhibits good electrical conductivity and a thermal conductivity of 5-10 W / (m·K), and shows no significant electrical noise or voltage fluctuations during discharge. The concentration of oxygen vacancies, particle size, and uniformity can be controlled by adjusting the high-energy ball milling time, milling speed, ball diameter, and ball-to-powder ratio. Its electrical and thermal conductivity can be appropriately adjusted by varying the amounts of multi-dimensional metal conductive agents and alkali metal additives.

[0016] This invention also relates to a method for preparing an oxygen-vacancy-rich nickel oxide cathode material with multiple surface defects for thermal batteries. The method employs a ball milling-induced defect-surface charge regulation-atomization quenching granulation-mixing, drying, and pulverizing process, specifically including the following steps: S1. Ball milling induced defects: High-energy ball milling of nickel oxide raw materials induces the generation of oxygen vacancies and the formation of surface defects. S2, Surface charge control: Disperse the oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S1 in a positive polyelectrolyte aqueous solution to obtain a positive potential material solution; disperse the multidimensional metal conductive agent in a negative polyelectrolyte aqueous solution to obtain a negative potential material solution; continuously stir the positive potential material solution and the negative potential material solution to achieve charge control; centrifuge and wash them respectively, and vacuum dry them to obtain materials carrying opposite charges; S3. Atomization quenching granulation: The positively charged oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S2 is mixed and dispersed in a dispersant to obtain a uniform suspension and continuously stirred; the suspension is atomized to form tiny droplets and then quenched to separate the ice particles carrying the material and freeze-dry. S4. Mixing, drying and pulverizing: The oxygen-rich vacancy multi-surface defect nickel oxide with multi-dimensional metal conductive agent embedded in step S3 is mixed with alkali metal additives at high speed in an environment with humidity less than 3%. After drying and pulverizing under inert atmosphere protection, the oxygen-rich vacancy multi-surface defect nickel oxide cathode material is obtained.

[0017] The first core step of this invention is to induce the generation of oxygen vacancies and surface defects through high-energy ball milling. In materials processing, high-energy ball milling can broadly meet various needs in laboratory and industrial production, and is frequently used for the physical mixing and modification of powder particles. During high-energy ball milling, the solid-solid contact interface between solid nickel oxide powder particles and the milling balls can induce the generation of oxygen vacancies and surface defects due to the mechanical shear force and compressive stress acting on the nickel oxide.

[0018] In one embodiment of the present invention, in step S1, the high-energy ball milling involves mixing nickel oxide and agate balls and placing them in a ball milling jar, then milling at a speed of 200-800 rpm for 1-8 hours. A high-energy ball milling time of less than 1 hour may result in the inability to form oxygen vacancies and surface defects; a ball milling time of more than 8 hours may lead to excessive ball milling, potentially causing the structure to become disordered again, and the concentration of oxygen vacancies and the degree of surface defects may actually decrease.

[0019] The second core step of this invention involves using polyelectrolytes to modulate the surface charge of oxygen-rich, multi-surface-defect nickel oxide and multi-dimensional metal conductive agents. The principle behind the different electrical properties of the polyelectrolyte aqueous solutions is that the polyelectrolytes dissolve in water and undergo hydrolysis, releasing charged ions that impart a specific electrical property to the polymer aqueous solution. The oxygen-rich, multi-surface-defect nickel oxide is dispersed in a positive polyelectrolyte aqueous solution, while the multi-dimensional metal conductive agent is dispersed in a negative polyelectrolyte aqueous solution. After continuous stirring, the mixture is centrifuged and washed multiple times, then vacuum dried to obtain materials carrying opposite charges. These materials are then assembled via electrostatic adsorption.

[0020] As one implementation scheme, in step S2, the oxygen-rich vacancy multi-surface defect nickel oxide powder is stirred and dispersed in an aqueous solution of diethylene glycol diacrylate positive polyelectrolyte with a mass percentage concentration of 5% to 25%; the multi-dimensional metal conductive agent is stirred and dispersed in an aqueous solution of poly(p-styrene sulfonate) negative polyelectrolyte with a mass percentage concentration of 5% to 25%; wherein the stirring and dispersion is carried out at a speed of 50 to 500 rpm for 0.5 to 5 hours.

[0021] As one implementation scheme, the mass percentage concentration of the positive / negative polyelectrolyte aqueous solution is preferably 5% to 25%. A mass percentage concentration below 5% requires increased processing time for pretreatment, reducing production efficiency, while a mass percentage concentration above 25% results in a viscous solution that is difficult to stir and leads to polyelectrolyte waste.

[0022] The third core step of the method of this invention is to perform atomization quenching granulation on the mixed material suspension under continuous stirring. The continuous stirring process can ensure that the mixed suspension of oxygen-rich vacancy multi-surface defect nickel oxide and multi-dimensional metal conductive agent is in a uniformly dispersed state, avoiding sedimentation caused by the weight of the materials; the atomization quenching can ensure that the uniform suspension of oxygen-rich vacancy multi-surface defect nickel oxide modified with metal conductive agent drawn by the peristaltic pump can quickly form ice particles after atomization, locking and maintaining the uniform dispersion and adhesion of the materials.

[0023] In one implementation scheme, in step S3, the dispersant is distilled water, ethanol, or a mixture of distilled water and ethanol. Regarding the selection of the dispersant, firstly, it should facilitate the uniform dispersion of positively charged oxygen-rich, multi-surface-defect nickel oxide and negatively charged, multi-dimensional metallic conductive agent; secondly, a dispersant with low viscosity should be selected, as excessively high viscosity may affect the peristaltic pump's delivery efficiency and lifespan; finally, a faster freezing rate in the refrigerant can improve the uniformity of quenching and processing efficiency.

[0024] As one implementation, in step S3, the uniform suspension is maintained by continuous stirring at a speed of 100-500 rpm. This continuous stirring process ensures that the suspension of oxygen-rich, multi-surface-defect nickel oxide mixed with the multi-dimensional metallic conductive agent remains uniformly dispersed, avoiding sedimentation caused by the weight of the materials.

[0025] As one implementation scheme, in step S3, the ice particles carrying the material are separated using a separation sieve, gravity sedimentation, or flat-spread evaporation method; the choice can be flexible based on the actual process conditions and the size of the ice particles. For example, for long-term continuous quenching treatment, ice particles can be periodically collected using a specialized separation sieve to achieve continuous batch production. For example, for small-batch production and short-term quenching treatment, after completing production in one go, the upper layer of refrigerant can be poured out after solid-liquid separation via gravity sedimentation, and the bottom ice particles can be collected.

[0026] As one implementation, in step S3, the freeze-drying temperature is -30 ~ -100℃, and the time is 8 ~ 24h.

[0027] As one implementation scheme, step S3, atomization quenching granulation, involves using a peristaltic pump to draw in a uniform suspension of material at a flow rate of 0.5~50 ml / min, atomizing it into tiny droplets which are then sprayed into a container containing a refrigerant. A peristaltic pump flow rate below 0.5 ml / min leads to reduced processing efficiency and increased production costs; a flow rate above 50 ml / min can cause delayed atomization, resulting in material accumulation between the peristaltic pump and the atomizer. Liquid nitrogen or dry ice is preferred as the refrigerant to achieve rapid droplet cooling and ensure material uniformity.

[0028] The fourth core step of this invention is the attachment and embedding of alkali metal additives into the surface of nickel oxide and its defects. The design of various defects such as surface cracks, pits, and pores promotes the adhesion of the alkali metal additives, which is beneficial for improving the high-temperature conductivity of the cathode material and the mutual wetting between it and the molten electrolyte with similar composition. This facilitates the melting and flow of the molten salt electrolyte during high-temperature discharge, accelerating the electrochemical reaction.

[0029] As one implementation, in step S4, the high-speed mixing speed is 400~1800 r / min and the time is 15~60 min.

[0030] As one implementation scheme, in step S4, the drying under an inert atmosphere is carried out at 200-500°C for 2-10 hours under an argon, nitrogen, or helium atmosphere. In some specific embodiments, the powder mixing, drying, and pulverizing process in step S4 involves weighing the material obtained in step S3 and the alkali metal additive in a drying room with a humidity of less than 3%, then transferring the mixture to a high-speed powder mixer for mixing. After mixing, the mixture is dried at 50-200°C for 2-10 hours under an inert atmosphere such as argon, nitrogen, or helium. The product is then collected and pulverized to obtain an oxygen-rich nickel oxide cathode material with multiple surface defects and numerous vacancies.

[0031] This invention also relates to the application of an oxygen-rich vacancy-multi-surface-defect nickel oxide cathode material, which can be used as a cathode or additive in thermal batteries. For example, when used as a cathode material in a thermal battery, the oxygen-rich vacancy-multi-surface-defect nickel oxide material prepared according to this invention is uniformly mixed with an electrolyte conductive agent and a binder in a specific ratio, and then a cathode sheet of a certain size is prepared by powder pressing. This cathode sheet is then assembled with an electrolyte sheet, a negative electrode sheet, and a current collector to obtain a single thermal battery cell using the oxygen-rich vacancy-multi-surface-defect nickel oxide material as the cathode. For example, as a small amount of additive (wt% = 5 ~ 10%) in a sulfide cathode material, it improves the thermal stability of the material and prevents damage to the active material from thermal shock during the initial stage of discharge. The cathode powder is then pressed into a sheet and assembled with an electrolyte sheet, a negative electrode sheet, and a current collector to obtain a single thermal battery cell using the oxygen-rich vacancy-multi-surface-defect nickel oxide material as the cathode additive.

[0032] Compared with the prior art, the present invention has the following beneficial effects: 1) The material prepared by this invention uses nickel oxide, which has high thermal stability and high theoretical capacity, as the positive electrode material of the thermal battery. The initial decomposition temperature is >650℃. Under the extreme high temperature environment of the thermal battery, there is no obvious decomposition, which can avoid the impact of thermal decomposition impurities and gas generation on the stability and safety of the battery system, and improve the capacity output capability and working life of the thermal battery. 2) This invention induces abundant oxygen vacancies and surface defects in nickel oxide through high-energy ball milling, which effectively improves the electronic structure of nickel oxide material, reduces electron transport barriers, enhances thermal strain resistance and electrochemical activity, and optimizes its electrochemical performance as a battery cathode material. 3) This invention improves the high-temperature conductivity of the cathode material and promotes the wettability and penetration of molten salt electrolytes with similar composition by attaching and embedding alkali metal additives into the outer surface and surface defects of nickel oxide particles.

[0033] 4) The multi-dimensional metal conductive agent of this invention preferentially fills and embeds in the grooves of surface defects, and the alkali metal additive is attached and dispersed on the outer surface of nickel oxide particles. The unique structure effectively reduces the electron transport barrier, reduces the internal resistance of the battery, and improves the utilization rate of the positive electrode material. At the same time, it avoids the problems that ordinary single-dimensional conductive agents may face at high temperatures, such as incomplete conductive network, poor interface contact or oxidation. 5) The present invention adopts a surface charge regulation-atomization quenching granulation-mixing drying and pulverizing process, which can achieve uniform and compact composite material compounding and reduce the hazards of powder dust, improve the production environment, and the process is highly operable, stable, and the product quality is safe and reliable, and it is easy to realize batch continuous production. Attached Figure Description

[0034] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a process flow diagram of the synthesis of the oxygen-rich, vacancy-rich, multi-surface-defect nickel oxide cathode material for thermal batteries according to the present invention. Figure 2 This refers to the oxygen vacancy concentration of nickel oxide with multiple surface defects and rich oxygen vacancies used in the thermal battery of the present invention. Figure 3 This is a schematic diagram of the structure of the oxygen-rich, vacancy-rich, multi-surface-defect nickel oxide cathode material for thermal batteries of the present invention; Figure 4 This is a comparison diagram of the surface electrical properties of nickel oxide with oxygen-rich vacancies and multiple surface defects before and after charge modulation in Example 1; Figure 5 This is a comparison diagram of the surface electrical properties of the multidimensional metallic conductive agent before and after charge modulation in Example 1; Figure 6 This is a schematic diagram of the adsorption assembly of materials with different charges in Example 1; Figure 7 These are material thermal analysis diagrams for Examples 1, 2, and 5; Figure 8 The battery discharge curves are for Examples 1, 2, 5 and Comparative Examples 1, 2, 3. Figure 9 Internal resistance diagrams of the thermal cells in Examples 1, 2, and 5 and Comparative Examples 1, 2, and 3 are shown. Figure 10 Here is a picture of a current collector for a thermal battery. Figure 11 These are the material thermal analysis diagrams for Examples 3 and 4 and Comparative Example 4; Figure 12 The internal resistance diagrams of the thermal cells in Examples 3, 4 and Comparative Example 4 are shown. Figure 13 The figures show the battery discharge curves for Examples 3, 4, and Comparative Example 4. Detailed Implementation

[0035] This invention relates to an oxygen-vacancy-rich nickel oxide cathode material with multiple surface defects for thermal batteries and its preparation method. First, by designing oxygen vacancy defects, the electronic structure of the nickel oxide material is improved, effectively reducing the band gap of the oxide and lowering the diffusion barrier of ions. This simultaneously enhances the electrochemical activity of the nickel oxide cathode material, promoting its reaction with ions in the electrolyte. Furthermore, oxygen vacancy engineering improves the material's resistance to thermal strain, reduces oxygen release at high temperatures, lowers the risk of thermal runaway, and optimizes the electrochemical performance of oxygen-vacancy-rich nickel oxide as a battery cathode material. Second, the design of various defects such as surface cracks, pits, and pores promotes the adhesion of conductive agents and additives. This facilitates the melting and flow of alkali metal additives and electrolytes during high-temperature discharge, expanding the area exposed to the electrolyte and accelerating the electrochemical reaction. Furthermore, introducing multi-dimensional metallic conductive agents can construct a stable three-dimensional conductive network, significantly improving the material's conductivity, reducing electron transport barriers, and decreasing battery internal resistance. This also avoids the problems that ordinary single-dimensional conductive agents (such as single-dimensional carbon black or metal powder) may face at high temperatures, such as incomplete conductive networks, poor interfacial contact, or oxidation. This is an effective means to improve the performance of nickel oxide cathode materials. Finally, embedding alkali metal additives in surface defects is beneficial for improving the high-temperature conductivity of the cathode material and the mutual wetting between it and the molten electrolyte with similar composition.

[0036] The present invention will be described in detail below with reference to embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several adjustments and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0037] Example 1 This embodiment relates to a nickel oxide cathode material with oxygen-rich vacancy multi-surface defect for thermal batteries. The cathode material consists of a multi-dimensional metal conductive agent and an alkali metal additive dispersed and loaded on oxygen-rich vacancy sites. Figure 2 Multiple surface defects Figure 3 The surface composition of the nickel oxide support. The oxygen-rich, vacancy-rich, multi-surface-defect nickel oxide support carries a positive charge after treatment with a positive polyelectrolyte. Figure 4 ), while multidimensional metal conductive agents, after being treated with negative polyelectrolytes, carry negative charges ( Figure 5 ), utilizing the charge affinity effect to assemble with each other in the dispersant ( Figure 6Finally, the mixture is uniformly mixed with alkali metal additives and then dried and pulverized in a drying chamber. The oxygen-rich, multi-surface-defect nickel oxide cathode material is rich in oxygen vacancies. Multi-dimensional metal conductive agents and alkali metal additives fill and adhere to various defects on the nickel oxide surface, such as cracks, pits, and pores, exhibiting good thermal stability with an initial decomposition temperature greater than 650℃. Figure 7 The thermal battery discharge curve is stable. Figure 8 ), battery internal resistance decreases ( Figure 9 ); Figure 9 The term "ordinary nickel oxide" refers to the nickel oxide raw material used in this embodiment.

[0038] In this embodiment, the oxygen-rich, vacancy-rich, multi-surface-defect nickel oxide cathode material for the thermal battery is prepared using a process of ball milling to induce defects, surface charge regulation, atomization quenching granulation, and powder mixing, drying, and pulverization (e.g., ...). Figure 1 The specific steps are as follows: S1. Ball milling induced defects: Nickel oxide raw material was mixed with agate balls and added to a ball mill jar for high-energy ball milling at 300 rpm for 6 hours; S2. Surface Charge Regulation: The oxygen-rich, vacant, multi-surface-defect nickel oxide powder obtained in step S1 was stirred and dispersed in a 10% (w / w) aqueous solution of diethylene glycol diacrylate positive polyelectrolyte. Zero-dimensional silver nanoparticles (approximately 30 nm in size) and one-dimensional silver nanowire conductive agents (approximately 40 nm in diameter and 30 μm in length) were stirred and dispersed in a 5% (w / w) aqueous solution of poly(p-styrene sulfonate) negative polyelectrolyte. After stirring and dispersing at 200 rpm for 3 h, the mixture was centrifuged and washed multiple times, then dried to obtain materials carrying opposite charges. S3. Atomization Quenching Granulation: The positively charged oxygen-rich vacancy multi-surface defect nickel oxide and multi-dimensional silver conductive agent obtained in step S2 are weighed and mixed at a mass ratio of 90:10. The mixture is dispersed in distilled water at a liquid-to-solid ratio of 15 to obtain a uniform suspension. The mixture is continuously stirred at 300 rpm. The material is drawn up by a peristaltic pump at a flow rate of 10 ml / min and atomized into tiny droplets. The droplets are then sprayed into a container filled with liquid nitrogen for quenching to form ice particles carrying the material. After production, the ice particles are separated by spreading and evaporating. The ice particle size is about 0.1 ~ 0.5 cm. The ice particles are then freeze-dried at -50℃ for 15 h.

[0039] S4. Mixing, drying and pulverizing: The multi-dimensional silver conductive agent modified oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S3 is mixed with lithium chloride additive at a mass percentage of 90:10. The mixture is then transferred to a high-speed powder mixer in a drying room with a humidity of less than 3% and mixed at a speed of 600 r / min for 30 min. Finally, it is dried at 150℃ for 5 h under argon protection and pulverized to obtain the oxygen-rich vacancy multi-surface defect nickel oxide cathode material.

[0040] The prepared material was used as the positive electrode material for a thermal battery. A nickel oxide positive electrode material rich in oxygen vacancies and with multiple surface defects was mixed with magnesium oxide and a LiCl-LiBr-LiF ternary molten salt electrolyte in a ratio of 80:4:16. This mixture was then pressed into a positive electrode sheet with a diameter of 30 mm and a thickness of approximately 1.5 mm. This positive electrode sheet was then combined with an electrolyte sheet (wt% LiCl-LiF-LiBr ternary electrolyte: wt% magnesium oxide = 60:40, diameter 30 mm, thickness approximately 1 mm), a lithium-boron alloy negative electrode sheet (LiB60, Yichang Yilong Electronic Materials Co., Ltd., diameter 26 mm, thickness approximately 0.4 mm), and a stainless steel current collector. Figure 10 After assembly, a single thermal battery cell with an oxygen-rich, multi-surface-defect nickel oxide material as the positive electrode was obtained. Electrical performance tests were conducted, and the battery showed low internal resistance. Figure 9 The discharge curve is stable. Figure 8 ).

[0041] Example 2 This embodiment relates to an oxygen-vacancy-rich nickel oxide cathode material with multiple surface defects for thermal batteries. The cathode material is composed of one-dimensional silver nanowires and two-dimensional silver nanosheets dispersed and loaded on the surface of an oxygen-vacancy-rich nickel oxide support. This oxygen-vacancy-rich nickel oxide cathode material for thermal batteries exhibits good thermal stability, reduced internal resistance of the thermal battery, and the absence of electrical noise and voltage fluctuations. The oxygen-vacancy-rich nickel oxide cathode material for thermal batteries in this embodiment is prepared using a process of ball milling to induce defects, surface charge regulation, atomization quenching granulation, and powder mixing, drying, and pulverization. The specific steps are as follows: S1. Ball milling induced defects: Nickel oxide raw material was mixed with agate balls and added to a ball mill jar for high-energy ball milling at 200 rpm for 8 hours; S2. Surface Charge Regulation: The oxygen-rich vacancy-rich nickel oxide powder with multiple surface defects obtained in step S1 was stirred and dispersed in a 15% (w / w) aqueous solution of diethylene glycol diacrylate positive polyelectrolyte. One-dimensional silver nanowires with a diameter of approximately 40 nm and a length of approximately 30 μm, and two-dimensional silver nanosheets with a thickness of approximately 50 nm and a lateral dimension of approximately 300 nm, acting as conductive agents, were stirred and dispersed in a 10% (w / w) aqueous solution of poly(p-styrene sulfonate) negative polyelectrolyte. After stirring and dispersing at 250 rpm for 3 h, the mixture was centrifuged and washed multiple times, then dried to obtain materials carrying opposite charges. S3. Atomization Quenching Granulation: The positively charged oxygen-rich vacancy multi-surface defect nickel oxide and multi-dimensional silver conductive agent obtained in step S2 are weighed and mixed at a mass ratio of 95:5. The mixture is dispersed in distilled water at a liquid-to-solid ratio of 20 to obtain a uniform suspension. The mixture is continuously stirred at 300 rpm. The material is drawn up by a peristaltic pump at a flow rate of 20 ml / min and atomized into tiny droplets. These droplets are then sprayed into a container filled with liquid nitrogen for quenching, forming ice particles carrying the material. During continuous production, the ice particles are periodically separated by a professional separation screen. The ice particle size is approximately 0.3 ~ 0.6 cm. The ice particles are then freeze-dried at -60℃ for 15 hours.

[0042] S4. Mixing, drying and pulverizing: The multi-dimensional silver conductive agent modified oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S3 is mixed with lithium carbonate additive at a mass percentage of 90:10. The mixture is then transferred to a high-speed powder mixer in a drying room with a humidity of less than 3% and mixed at a speed of 800 r / min for 25 min. After drying at 120℃ for 6 h under nitrogen protection and pulverizing, the oxygen-rich vacancy multi-surface defect nickel oxide cathode material is obtained.

[0043] The prepared material was used as the positive electrode material for a thermal battery. A nickel oxide positive electrode material rich in oxygen vacancies and with multiple surface defects, along with magnesium oxide and LiCl-LiBr-LiF ternary molten salt electrolyte, was mixed in a ratio of 80:2:18 and then pressed into a positive electrode sheet with a diameter of 20 mm and a thickness of approximately 1.5 mm. This positive electrode sheet was then combined with an electrolyte sheet (wt% LiCl-LiF-LiBr ternary electrolyte: wt% magnesium oxide = 60:40, diameter 20 mm, thickness approximately 1 mm), a lithium boron alloy negative electrode sheet (LiB60, Yichang Yilong Electronic Materials Co., Ltd., diameter 18 mm, thickness approximately 0.4 mm), and a stainless steel current collector (…). Figure 10 After assembly, a single thermal battery cell with an oxygen-rich, multi-surface-defect nickel oxide material as the positive electrode was obtained. Electrical performance tests were conducted, and the battery showed low internal resistance. Figure 9 The discharge curve is stable. Figure 8 ).

[0044] Example 3 This embodiment relates to an oxygen-vacancy-rich nickel oxide cathode material with multiple surface defects for thermal batteries. The cathode material is composed of 1D gold nanowires and 3D gold nanospheres dispersed and loaded on the surface of an oxygen-vacancy-rich nickel oxide support. This oxygen-vacancy-rich nickel oxide cathode material for thermal batteries exhibits good thermal stability, reduced internal resistance of the thermal battery, and the absence of electrical noise and voltage fluctuations. The oxygen-vacancy-rich nickel oxide cathode material for thermal batteries in this embodiment is prepared using a process of ball milling to induce defects, surface charge regulation, atomization quenching granulation, and powder mixing, drying, and pulverization. The specific steps are as follows: S1. Ball milling induced defects: Nickel oxide raw material was mixed with agate balls and then added to a ball milling jar and ball milled at 400 rpm for 5 hours for high-energy ball milling; S2. Surface Charge Regulation: The oxygen-rich vacancy-rich nickel oxide powder with multiple surface defects obtained in step S1 was stirred and dispersed in a 10% (w / w) aqueous solution of diethylene glycol diacrylate positive polyelectrolyte. One-dimensional gold nanowires with a diameter of approximately 40 nm and a length of approximately 30 μm and three-dimensional gold nanospheres with a size of approximately 300 nm conductive agents were stirred and dispersed in a 15% (w / w) aqueous solution of poly(p-styrene sulfonate) negative polyelectrolyte. After stirring and dispersing at 250 rpm for 4 h, the mixture was centrifuged and washed multiple times, then dried to obtain materials carrying opposite charges. S3. Atomization Quenching Granulation: The positively charged oxygen-rich vacancy multi-surface defect nickel oxide and multi-dimensional silver conductive agent obtained in step S2 are weighed and mixed at a mass ratio of 95:5. The mixture is dispersed in distilled water at a liquid-to-solid ratio of 15 to obtain a uniform suspension and continuously stirred at 200 rpm. The material is drawn up by a peristaltic pump at a flow rate of 25 ml / min and atomized into tiny droplets, which are then sprayed into a container filled with liquid nitrogen for quenching to form ice particles carrying the material. After production, the ice particles are separated by gravity sedimentation. The ice particle size is about 0.3 ~ 0.8 cm and freeze-dried at -50℃ for 20 h.

[0045] S4. Mixing, drying and pulverizing: The multi-dimensional silver conductive agent modified oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S3 is mixed with potassium chloride additive at a mass percentage of 95:5. The mixture is then transferred to a high-speed powder mixer in a drying room with a humidity of less than 3% and mixed at a speed of 1000 r / min for 20 min. After drying at 80℃ for 8 h under nitrogen protection and pulverizing, the oxygen-rich vacancy multi-surface defect nickel oxide cathode material is obtained.

[0046] The prepared material was used as an additive for the positive electrode material of a thermal battery. FeS2: oxygen-rich vacancy multi-surface-defect nickel oxide positive electrode material: magnesium oxide: LiCl-LiBr-LiF ternary molten salt electrolyte was mixed in a ratio of 75:5:2:18 and then prepared into a positive electrode sheet with a diameter of 30 mm and a thickness of approximately 1.5 mm by powder pressing. This was then combined with an electrolyte sheet (wt% LiCl-LiF-LiBr ternary electrolyte: wt% magnesium oxide = 60:40, diameter 30 mm, thickness approximately 1 mm), a lithium boron alloy negative electrode sheet (LiB60, Yichang Yilong Electronic Materials Co., Ltd., diameter 26 mm, thickness approximately 0.4 mm), and a stainless steel current collector (…). Figure 10 After assembly, a single thermal cell is obtained using nickel oxide material with oxygen-rich vacancies and multiple surface defects as the positive electrode additive, which improves the thermal stability of the positive electrode material. Figure 11 Electrical performance tests were conducted, and the battery showed low internal resistance.Figure 12 The discharge curve is stable. Figure 13 ).

[0047] Example 4 This embodiment relates to an oxygen-vacancy-rich nickel oxide cathode material with multiple surface defects for thermal batteries. The cathode material is composed of 0D gold nanowires, 1D copper nanowires, and 2D silver nanosheets dispersed and loaded on the surface of an oxygen-vacancy-rich nickel oxide support. This oxygen-vacancy-rich nickel oxide cathode material for thermal batteries exhibits good thermal stability, reduced internal resistance of the thermal battery, and the absence of electrical noise and voltage fluctuations. The oxygen-vacancy-rich nickel oxide cathode material for thermal batteries in this embodiment is prepared using a process of ball milling to induce defects, surface charge regulation, atomization quenching granulation, and powder mixing, drying, and pulverization. The specific steps are as follows: S1. Ball milling induced defects: Nickel oxide raw material was mixed with agate balls and added to a ball mill jar for high-energy ball milling at 400 rpm for 4 hours; S2. Surface Charge Regulation: The oxygen-rich vacancy-rich nickel oxide powder with multiple surface defects obtained in step S1 was stirred and dispersed in a 10% (w / w) aqueous solution of diethylene glycol diacrylate positive polyelectrolyte. Zero-dimensional gold nanoparticles (approximately 25 nm in size), one-dimensional copper nanowires (approximately 40 nm in diameter and 30 μm in length), and two-dimensional silver nanosheets (approximately 50 nm thick and 300 nm in lateral dimension) were stirred and dispersed in a 10% (w / w) aqueous solution of poly(p-styrene sulfonate) negative polyelectrolyte. After stirring and dispersing at 250 rpm for 5 h, the mixture was centrifuged and washed multiple times, then dried to obtain materials carrying opposite charges. S3. Atomization Quenching Granulation: The positively charged oxygen-rich vacancy multi-surface defect nickel oxide and multi-dimensional silver conductive agent obtained in step S2 are weighed and mixed at a mass ratio of 90:10. The mixture is dispersed in ethanol at a liquid-to-solid ratio of 30 to obtain a uniform suspension and continuously stirred at 400 rpm. The material is drawn up by a peristaltic pump at a flow rate of 10 ml / min and atomized into tiny droplets, which are then sprayed into a container containing dry ice for quenching to form ice particles carrying the material. After production, the ice particles are separated by gravity sedimentation. The ice particle size is about 0.3 ~ 0.8 cm and freeze-dried at -80℃ for 12 h.

[0048] S4. Mixing, drying and pulverizing: The multi-dimensional silver conductive agent modified oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S3 is mixed with lithium chloride and lithium bromide additives at a mass percentage of 90:5:5. The mixture is then transferred to a high-speed powder mixer in a drying room with a humidity of less than 3% and mixed at a speed of 1200 r / min for 30 min. After drying at 90℃ for 5 h under nitrogen protection and pulverizing, the oxygen-rich vacancy multi-surface defect nickel oxide cathode material is obtained.

[0049] The prepared material was used as an additive for the positive electrode material of a thermal battery. FeS2: oxygen-rich vacancy multi-surface-defect nickel oxide positive electrode material: magnesium oxide: LiCl-LiF-LiBr ternary molten salt electrolyte was mixed in a ratio of 70:10:5:15 and then prepared into a positive electrode sheet with a diameter of 20 mm and a thickness of approximately 1.5 mm by powder pressing. This was then combined with an electrolyte sheet (wt% LiCl-LiF-LiBr ternary electrolyte: wt% magnesium oxide = 60:40, diameter 20 mm, thickness approximately 1 mm), a lithium boron alloy negative electrode sheet (LiB60, Yichang Yilong Electronic Materials Co., Ltd., diameter 18 mm, thickness approximately 0.4 mm), and a stainless steel current collector (…). Figure 10 After assembly, a single thermal cell is obtained using nickel oxide material with oxygen-rich vacancies and multiple surface defects as the positive electrode additive, which improves the thermal stability of the positive electrode material. Figure 11 Electrical performance tests were conducted, and the battery showed low internal resistance. Figure 12 The discharge curve is stable. Figure 13 ).

[0050] Example 5 This embodiment relates to an oxygen-vacancy-rich nickel oxide cathode material with multiple surface defects for thermal batteries. The cathode material is composed of 0D silver nanowires, 1D silver nanowires, 2D silver nanosheets, and 3D silver nanospheres dispersedly loaded on the surface of an oxygen-vacancy-rich nickel oxide carrier. This oxygen-vacancy-rich nickel oxide cathode material for thermal batteries exhibits good thermal stability, reduced internal resistance of the thermal battery, and the absence of electrical noise and voltage fluctuations. The oxygen-vacancy-rich nickel oxide cathode material for thermal batteries in this embodiment is prepared using a process of ball milling to induce defects, surface charge regulation, atomization quenching granulation, and powder mixing, drying, and pulverization. The specific steps are as follows: S1. Ball milling induced defects: Nickel oxide raw material was mixed with agate balls and then added to a ball milling jar and ball milled at 400 rpm for 5 hours for high-energy ball milling; S2. Surface Charge Regulation: The oxygen-rich vacancy multi-surface-defect nickel oxide powder obtained in step S1 was stirred and dispersed in a 10% (w / w) aqueous solution of diethylene glycol diacrylate positive polyelectrolyte. Conductive agents including 0-dimensional silver nanowires (approximately 30 nm in size), 1-dimensional silver nanowires (approximately 40 nm in diameter and 30 μm in length), 2-dimensional silver nanosheets (approximately 50 nm thick and 300 nm in lateral dimension), and 3-dimensional silver nanospheres (approximately 300 nm in size) were stirred and dispersed in a 15% (w / w) aqueous solution of poly(p-styrene sulfonate) negative polyelectrolyte. After stirring and dispersing at 350 rpm for 2 h, the mixture was centrifuged and washed multiple times, then dried to obtain materials carrying opposite charges. S3. Atomization Quenching Granulation: The positively charged oxygen-rich vacancy multi-surface defect nickel oxide and multi-dimensional silver conductive agent obtained in step S2 are weighed and mixed at a mass ratio of 95:5. The mixture is dispersed in ethanol at a liquid-to-solid ratio of 15 to obtain a uniform suspension and continuously stirred at 400 rpm. The material is drawn up by a peristaltic pump at a flow rate of 5 ml / min and atomized into tiny droplets, which are then sprayed into a container containing dry ice for quenching to form ice particles carrying the material. After production, the ice particles are separated by spreading and evaporating. The ice particle size is about 0.1 ~ 0.5 cm. The ice particles are freeze-dried at -60℃ for 12 h.

[0051] S4. Mixing, drying and pulverizing: The multi-dimensional silver conductive agent modified oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S3 is mixed with lithium chloride and potassium chloride additives at a mass percentage of 95:3:2. The mixture is then transferred to a high-speed powder mixer in a drying room with a humidity of less than 3% and mixed at a speed of 1300 r / min for 20 min. After drying at 160℃ for 3 h under nitrogen protection and pulverizing, the oxygen-rich vacancy multi-surface defect nickel oxide cathode material is obtained.

[0052] The prepared material was used as the positive electrode material for a thermal battery. A nickel oxide positive electrode material rich in oxygen vacancies and with multiple surface defects, along with magnesium oxide and LiCl-LiF-LiBr ternary molten salt electrolyte, was mixed in a ratio of 70:5:25 and then pressed into a positive electrode sheet with a diameter of 30 mm and a thickness of approximately 1.5 mm. This positive electrode sheet was then combined with an electrolyte sheet (wt% LiCl-LiF-LiBr ternary electrolyte: wt% magnesium oxide = 60:40, diameter 30 mm, thickness approximately 1 mm), a lithium boron alloy negative electrode sheet (LiB60, Yichang Yilong Electronic Materials Co., Ltd., diameter 26 mm, thickness approximately 0.4 mm), and a stainless steel current collector. Figure 10 After assembly, a single thermal battery cell with an oxygen-rich, multi-surface-defect nickel oxide material as the positive electrode was obtained. Electrical performance tests were conducted, and the battery showed low internal resistance. Figure 9 The discharge curve is stable. Figure 8 ).

[0053] Comparative Example 1 The difference from Example 1 is that the oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S1 is directly used as the positive electrode material, without adding multi-dimensional metal conductive agents and alkali metal additives.

[0054] Nickel oxide raw material was mixed with agate balls and then ball-milled at 300 rpm for 6 hours for high-energy ball milling. This mixture was then used as the positive electrode material for a thermal battery. A nickel oxide positive electrode material with oxygen-rich vacancies and multiple surface defects was mixed with magnesium oxide and LiCl-LiBr-LiF ternary molten salt electrolyte in a ratio of 80:4:16. This mixture was then pressed into a positive electrode sheet with a diameter of 30 mm and a thickness of approximately 1.5 mm. This positive electrode sheet was then combined with an electrolyte sheet (wt% LiCl-LiF-LiBr ternary electrolyte: wt% magnesium oxide = 60:40, diameter 30 mm, thickness approximately 1 mm), a lithium-boron alloy negative electrode sheet (LiB60, Yichang Yilong Electronic Materials Co., Ltd., diameter 26 mm, thickness approximately 0.4 mm), and a stainless steel current collector. Figure 10 After assembly, a single thermal battery cell with an oxygen-rich, multi-surface-defect nickel oxide material as the positive electrode was obtained. Electrical performance testing was conducted, and the battery showed high internal resistance in the later stages of discharge. Figure 9 ), discharge specific capacity decreased ( Figure 8 ).

[0055] Comparative Example 2 The difference from Example 1 is that the synthesis process does not involve S2 surface charge regulation of the oxygen-vacancy-rich multi-surface-defect nickel oxide and the multi-dimensional metal conductive agent; the remaining process steps are the same. The oxygen-vacancy-rich multi-surface-defect nickel oxide cathode material for thermal batteries in this example is prepared using a ball milling-induced defect-atomized quenching granulation-mixing, drying, and pulverizing process. The specific steps are as follows: S1. Ball milling induced defects: Nickel oxide raw material was mixed with agate balls and added to a ball mill jar for high-energy ball milling at 300 rpm for 6 hours; S2. Atomization Quenching Granulation: The oxygen-rich vacancy multi-surface defect nickel oxide and multi-dimensional silver conductive agent obtained in step S1 are weighed and mixed at a mass ratio of 90:10. The mixture is dispersed in distilled water at a liquid-to-solid ratio of 15 to obtain a uniform suspension. The mixture is continuously stirred at 300 rpm. The material is drawn up by a peristaltic pump at a flow rate of 10 ml / min and atomized into tiny droplets. The droplets are then sprayed into a container filled with liquid nitrogen for quenching to form ice particles carrying the material. After production, the ice particles are separated by spreading and evaporating. The ice particle size is about 0.1 ~ 0.5 cm. The ice particles are then freeze-dried at -50℃ for 15 h.

[0056] S3. Mixing, drying and pulverizing: The multi-dimensional silver conductive agent modified oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S2 is mixed with lithium chloride additive at a mass percentage of 90:10. The mixture is then transferred to a high-speed powder mixer in a drying room with a humidity of less than 3% and mixed at a speed of 600 r / min for 30 min. Finally, it is dried at 150℃ for 5 h under argon protection and pulverized to obtain the oxygen-rich vacancy multi-surface defect nickel oxide cathode material.

[0057] The prepared material was used as the positive electrode material for a thermal battery. A nickel oxide positive electrode material rich in oxygen vacancies and with multiple surface defects was mixed with magnesium oxide and a LiCl-LiBr-LiF ternary molten salt electrolyte in a ratio of 80:4:16. This mixture was then pressed into a positive electrode sheet with a diameter of 30 mm and a thickness of approximately 1.5 mm. This positive electrode sheet was then combined with an electrolyte sheet (wt% LiCl-LiF-LiBr ternary electrolyte: wt% magnesium oxide = 60:40, diameter 30 mm, thickness approximately 1 mm), a lithium-boron alloy negative electrode sheet (LiB60, Yichang Yilong Electronic Materials Co., Ltd., diameter 26 mm, thickness approximately 0.4 mm), and a stainless steel current collector. Figure 10 After assembly, a single thermal battery cell with an oxygen-rich, multi-surface-defect nickel oxide material as the positive electrode was obtained. Electrical performance testing was conducted, and the battery showed high internal resistance in the later stages of discharge. Figure 9 The discharge curve shows obvious fluctuations. Figure 8 ).

[0058] Comparative Example 3 The difference from Example 1 is that the synthesis process changes S3 atomization quenching granulation to S3 dispersion centrifugal drying; the remaining process steps are the same. The oxygen-rich, multi-surface-defect nickel oxide cathode material for thermal batteries in this example is prepared using a ball milling-induced defect-surface charge regulation-dispersion centrifugal drying-mixing-drying and pulverizing process. The specific steps are as follows: S1. Ball milling induced defects: Nickel oxide raw material was mixed with agate balls and added to a ball mill jar for high-energy ball milling at 300 rpm for 6 hours; S2. Surface Charge Regulation: The oxygen-rich, vacant, multi-surface-defect nickel oxide powder obtained in step S1 was stirred and dispersed in a 10% (w / w) aqueous solution of diethylene glycol diacrylate positive polyelectrolyte. Zero-dimensional silver nanoparticles (approximately 30 nm in size) and one-dimensional silver nanowire conductive agents (approximately 40 nm in diameter and 30 μm in length) were stirred and dispersed in a 5% (w / w) aqueous solution of poly(p-styrene sulfonate) negative polyelectrolyte. After stirring and dispersing at 200 rpm for 3 h, the mixture was centrifuged and washed multiple times, then dried to obtain materials carrying opposite charges. S3. Dispersion and centrifugal drying: Weigh and mix the positively charged oxygen-rich vacancy multi-surface defect nickel oxide and multi-dimensional silver conductive agent obtained in step S2 at a mass ratio of 90:10. Disperse the mixture in distilled water at a liquid-to-solid ratio of 15 to obtain a uniform suspension. Centrifuge at 5000 rpm for 3 min, collect the sample and freeze-dry at -50℃ for 15 h.

[0059] S4. Mixing, drying and pulverizing: The multi-dimensional silver conductive agent modified oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S2 is mixed with lithium chloride additive at a mass percentage of 90:10. The mixture is then transferred to a high-speed powder mixer in a drying room with a humidity of less than 3% and mixed at a speed of 600 r / min for 30 min. Finally, it is dried at 150℃ for 5 h under argon protection and pulverized to obtain the oxygen-rich vacancy multi-surface defect nickel oxide cathode material.

[0060] The prepared material was used as the positive electrode material for a thermal battery. A nickel oxide positive electrode material rich in oxygen vacancies and with multiple surface defects was mixed with magnesium oxide and a LiCl-LiBr-LiF ternary molten salt electrolyte in a ratio of 80:4:16. This mixture was then pressed into a positive electrode sheet with a diameter of 30 mm and a thickness of approximately 1.5 mm. This positive electrode sheet was then combined with an electrolyte sheet (wt% LiCl-LiF-LiBr ternary electrolyte: wt% magnesium oxide = 60:40, diameter 30 mm, thickness approximately 1 mm), a lithium-boron alloy negative electrode sheet (LiB60, Yichang Yilong Electronic Materials Co., Ltd., diameter 26 mm, thickness approximately 0.4 mm), and a stainless steel current collector. Figure 10 After assembly, a single thermal battery cell with an oxygen-rich, multi-surface-defect nickel oxide material as the positive electrode was obtained. Electrical performance testing was conducted, and the battery showed high internal resistance in the later stages of discharge. Figure 9 ), discharge specific capacity decreased ( Figure 8 ).

[0061] Comparative Example 4 Using FeS2 as the positive electrode material for a thermal battery, a ternary molten salt electrolyte of FeS2:magnesium oxide:LiCl-LiF-LiBr in a ratio of 80:4:16 was mixed and then prepared into a positive electrode sheet with a diameter of 30 mm and a thickness of approximately 1.5 mm by powder pressing. This positive electrode sheet was then combined with an electrolyte sheet (wt% LiCl-LiF-LiBr ternary electrolyte:wt% magnesium oxide = 60:40, 30 mm in diameter, approximately 1 mm thick), a lithium-boron alloy negative electrode sheet (LiB60, Yichang Yilong Electronic Materials Co., Ltd., 26 mm in diameter), and a stainless steel current collector. Figure 10 After assembly, a single thermal battery cell with FeS2 material as the positive electrode was obtained. Thermal analysis and electrical performance tests were conducted, revealing poor thermal stability of the material. Figure 11 The battery discharge curve has poor stability. Figure 13 ).

[0062] In summary, this invention employs a process of ball milling-induced defects, surface charge regulation, atomization quenching granulation, and powder mixing and drying to prepare oxygen-vacancy-rich nickel oxide cathode material with multiple surface defects. Nickel oxide possesses high thermal stability and high theoretical capacity. Firstly, oxygen vacancy design improves the electronic structure of the nickel oxide material and lowers the diffusion barrier of ions, enhancing the material's resistance to thermal strain. Secondly, the introduction of multi-dimensional metal conductive agents significantly improves the conductivity of the composite material, reduces battery internal resistance, and increases the utilization rate of the cathode material. Finally, the design of various defects such as surface cracks, pits, and pores promotes the adhesion of conductive agents and additives, facilitating the flow, penetration, and mutual wetting of alkali metal additives and electrolytes during high-temperature discharge, accelerating electrochemical reactions, and optimizing the electrochemical performance of oxygen-vacancy-rich nickel oxide as a battery cathode material. This method is easily scalable for continuous mass production and features strong process operability, high stability, and reliable product quality and safety.

[0063] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A nickel oxide cathode material rich in oxygen vacancies and with multiple surface defects for thermal batteries, characterized in that, The nickel oxide cathode material is composed of a multi-dimensional metal conductive agent and an alkali metal additive dispersed and loaded on the surface of an oxygen-rich nickel oxide carrier with multiple surface defects. The dispersion is such that the multi-dimensional metal conductive agent preferentially fills and is embedded in the surface defect grooves, while the alkali metal additive is attached and dispersed on the outer surface of the nickel oxide particles. The multi-dimensional metal conductive agent is a combination of two or more of the following: 0-dimensional metal nanoparticles, 1-dimensional metal nanowires, 2-dimensional metal nanosheets, and 3-dimensional metal nanoblocks.

2. The nickel oxide cathode material according to claim 1, characterized in that, Includes at least one of the following technical features: A1. Nickel oxide crystals have abundant oxygen vacancies inside and one or more defects such as cracks, pits, and pores on the surface, which provide filling and embedding sites and spaces for multi-dimensional metallic conductive agents. A2. The metals of the multidimensional metal conductive agent are one or more combinations of gold, silver, copper, nickel, aluminum, magnesium, and zinc. A3. The alkali metal additive is one or more of lithium carbonate, lithium chloride, lithium fluoride, lithium bromide, potassium iodide, potassium chloride, and calcium chloride; A4. In the nickel oxide cathode material, the mass percentages of the oxygen-rich vacancy multi-surface defect nickel oxide carrier, the multi-dimensional metal conductive agent, and the alkali metal additive are 75-95%, 2-10%, and 3-15%, respectively.

3. The nickel oxide cathode material according to claim 1, characterized in that, The nickel oxide cathode material has an initial decomposition temperature of 650-800℃, uniform particle size with a particle size of less than 100μm, good electrical conductivity, and a thermal conductivity of 5-10W / (m·K).

4. A method for preparing the nickel oxide cathode material according to claim 1, characterized in that, The method includes the following steps: S1. Ball milling induced defects: High-energy ball milling of nickel oxide raw materials induces the generation of oxygen vacancies and the formation of surface defects. S2, Surface charge control: Disperse the oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S1 in an aqueous solution of positive polyelectrolyte to obtain a positive potential material solution; A multidimensional metal conductive agent is dispersed in an aqueous solution of a negatively charged polyelectrolyte to obtain a negatively charged material solution; the positively charged material solution and the negatively charged material solution are continuously stirred to achieve charge control, and then centrifuged, washed, and vacuum dried to obtain materials carrying opposite charges; S3. Atomization quenching granulation: The positively charged oxygen-rich vacancy multi-surface defect nickel oxide obtained in step S2 is mixed with the negatively charged multi-dimensional metal conductive agent and then dispersed in a dispersant to obtain a uniform suspension and continuously stirred; the suspension is atomized to form tiny droplets and then quenched to separate the ice particles carrying the material and freeze-dry. S4. Mixing, drying and pulverizing: The oxygen-rich vacancy multi-surface defect nickel oxide with multi-dimensional metal conductive agent embedded in step S3 is mixed with alkali metal additives at high speed in an environment with humidity less than 3%. After drying and pulverizing under inert atmosphere protection, the oxygen-rich vacancy multi-surface defect nickel oxide cathode material is obtained.

5. The preparation method according to claim 4, characterized in that, In step S2, the oxygen-rich vacancy multi-surface defect nickel oxide powder is stirred and dispersed in an aqueous solution of diethylene glycol diacrylate positive polyelectrolyte with a mass percentage concentration of 5% to 25%; the multi-dimensional metal conductive agent is stirred and dispersed in an aqueous solution of poly(p-styrene sulfonate) negative polyelectrolyte with a mass percentage concentration of 5% to 25%; wherein the stirring and dispersion is carried out at a speed of 50 to 500 rpm for 0.5 to 5 hours.

6. The preparation method according to claim 4, characterized in that, Step S3 includes at least one of the following technical features: B1. The dispersant is distilled water, ethanol, or a mixture of distilled water and ethanol; B2. The uniform suspension is maintained by continuous stirring at a speed of 100-500 rpm; B3. Ice particles carrying materials are separated by separation screening, gravity sedimentation, or flat-spread volatilization. B4. The freeze-drying temperature is -30 ~ -100℃, and the time is 8 ~ 24h.

7. The preparation method according to claim 4, characterized in that, Step S3, atomization quenching granulation, includes using a peristaltic pump to draw up a uniform suspension of material at a flow rate of 0.5 to 50 ml / min and atomizing it into tiny droplets which are then sprayed into a container containing a refrigerant.

8. The preparation method according to claim 4, characterized in that, In step S4, the drying under an inert atmosphere is carried out at 200-500°C for 2-10 hours under an argon, nitrogen, or helium atmosphere. And / or, the high-speed mixing speed is 400 ~ 1800 r / min, and the time is 15 ~ 60 min.

9. The use of a nickel oxide cathode material according to any one of claims 1-3, or a nickel oxide cathode material prepared by the method according to any one of claims 4-8, as a cathode or cathode additive in a thermal battery.

10. The use according to claim 9, characterized in that, The nickel oxide cathode material is used as an additive for the sulfide cathode material, and the addition amount is 5wt% to 10wt%.

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