A semi-solid battery and a preparation process thereof

Abstract

The application belongs to the technical field of lithium ion batteries, and particularly relates to a semi-solid battery and a preparation process thereof; the semi-solid battery comprises a positive electrode sheet, a negative electrode sheet and a composite solid electrolyte layer; the composite solid electrolyte layer is a ternary composite system comprising a polymer matrix, an inorganic solid electrolyte and a lithium salt, and further comprises an interface regulator; the positive electrode sheet and / or the negative electrode sheet contain the same inorganic solid electrolyte powder as in the composite solid electrolyte layer; a positive electrode active material is a high-nickel ternary material coated and modified by a lithium compound; and a negative electrode active material is a porous silicon / hard carbon composite material treated by pre-lithiation; by designing a novel composite solid electrolyte system, optimizing an electrode structure and an interface regulation strategy, developing a low-energy-consumption compatible preparation process, simultaneously adapting to soft packaging and efficient thermal management, the ion transmission performance, the interface stability and the cycle life of the semi-solid battery are significantly improved, and the semi-solid battery can be mass-produced and precisely matched with unmanned aerial vehicle application scenarios.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a semi-solid-state battery and its preparation process. Background Technology

[0002] With the rapid development of the new energy industry, traditional liquid lithium-ion batteries have become increasingly difficult to meet the demands of high-end applications due to safety hazards such as electrolyte leakage, flammability, and explosion, as well as energy density approaching theoretical limits. Semi-solid-state batteries, which partially or completely replace liquid electrolytes with solid electrolytes, combine the high ionic conductivity of liquid batteries with the high safety of solid-state batteries. They can also be matched with high-specific-capacity electrode materials (such as silicon-based anodes and high-nickel ternary cathodes), significantly improving battery energy density and becoming a current research hotspot in the battery field.

[0003] Current semi-solid-state battery technology still faces several technical bottlenecks: First, regarding solid electrolytes, while mainstream sulfide solid electrolytes have high ionic conductivity, they suffer from poor air stability, are prone to hydrolysis producing toxic gases, and have poor interfacial compatibility with electrode materials. Oxide solid electrolytes (such as LLZO and LATP) exhibit excellent chemical stability, but their ionic conductivity is relatively low, especially at low temperatures, resulting in insufficient ion transport capacity, and they also exhibit significant interfacial impedance with the electrodes. Second, the electrode-electrolyte interface is a prominent issue. In semi-solid-state batteries, interfacial gaps easily form between the solid electrolyte and the active electrode materials, hindering ion transport and causing excessive interfacial impedance, severely impacting the battery's rate performance and cycle stability. Third, the manufacturing process has poor compatibility. Current solid-state battery manufacturing often employs high-temperature sintering and high-pressure molding processes, which are not only energy-intensive and costly but also prone to damaging the electrode material structure, making large-scale mass production difficult. Fourth, the packaging and thermal management of pouch semi-solid-state batteries lack adaptability. Existing packaging processes easily lead to delamination between the solid electrolyte and the electrode interface, resulting in heat accumulation during high-rate charging and discharging, which is difficult to dissipate and further exacerbates performance degradation.

[0004] In existing semi-solid-state batteries using LLZO oxide solid electrolytes, the room temperature ionic conductivity is only 10. -4 -10 -3 S / cm, interfacial impedance exceeding 500 Ω·cm 2 After 200 cycles at 2C, the capacity retention rate is less than 80%. Semi-solid batteries using sulfide solid electrolytes exhibit significant performance degradation when fabricated in air, and the high-temperature sintering process leads to uneven electrode compaction density and poor battery consistency. Therefore, developing a composite solid electrolyte with high ionic conductivity and excellent interfacial compatibility, coupled with a low-energy-consumption and highly compatible fabrication process, to achieve high safety, long cycle life, and large-scale fabrication of semi-solid batteries has significant practical implications and application value.

[0005] Therefore, we propose a semi-solid-state battery and its fabrication process to solve the above problems. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the technical challenges of existing semi-solid batteries, such as low ionic conductivity of solid electrolytes, high electrode-electrolyte interface impedance, high energy consumption in fabrication processes, and poor compatibility with pouch packaging, and because existing batteries struggle to meet the stringent requirements of drones for lightweight design, high-rate charging and discharging, wide-temperature operation, and high safety, this invention provides a semi-solid battery and its fabrication process. By designing a novel composite solid electrolyte system, optimizing electrode structure and interface control strategies, and developing a low-energy-consumption compatible fabrication process, this invention also adapts to pouch packaging and efficient thermal management, significantly improving the ion transport performance, interface stability, and cycle life of the semi-solid battery. This enables large-scale mass production and precise matching of drone application scenarios.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0010] A semi-solid battery includes a positive electrode, a negative electrode, and a composite solid electrolyte layer;

[0011] The composite solid electrolyte layer is a ternary composite system comprising a polymer matrix, an inorganic solid electrolyte, and a lithium salt, and also includes an interface modifier.

[0012] The positive electrode and / or the negative electrode contain the same inorganic solid electrolyte powder as that in the composite solid electrolyte layer;

[0013] The positive electrode active material of the positive electrode sheet is a high-nickel ternary material modified by lithium compound coating;

[0014] The negative electrode active material of the negative electrode sheet is a porous silicon / hard carbon composite material that has undergone pre-lithiation treatment.

[0015] Furthermore, the interface modifier is perfluorooctyltriethoxysilane; in the composite solid electrolyte layer, the polymer matrix is ​​polyethylene oxide, and the inorganic solid electrolyte is Li7La3Zr2O. 12 The nanoparticles, wherein the lithium salt is LiTFSI; preferably, the composite solid electrolyte layer is composed of the following components by mass fraction: 25-35% polyethylene oxide, Li7La3Zr2O 12 40-50% nanoparticles, 15-20% LiTFSI, and 1-3% perfluorooctyltriethoxysilane.

[0016] Furthermore, the high-nickel ternary material is LiNi.0.9 Co 0.05 Mn 0.05 O2, wherein the lithium compound is LiPO3, and the coating thickness is 3-5 nm; preferably, the positive electrode sheet is composed of a positive electrode active material, a conductive agent, a binder, and Li7La3Zr2O. 12 The nanoparticles are prepared by mixing them in a mass ratio of 85-92:3-6:2-4:3-5.

[0017] Further, in the pre-lithiated porous silicon / hard carbon composite material, the mass ratio of porous silicon to hard carbon is 35:65, the degree of pre-lithiation is 6-8%, and the porosity of the porous silicon is 40-50%; preferably, the negative electrode sheet is composed of a negative electrode active material, a conductive agent, a binder, and Li7La3Zr2O. 12 The nanoparticles are prepared by mixing them in a mass ratio of 88-94:2-5:2-3:2-4.

[0018] Furthermore, the room temperature ionic conductivity of the composite solid electrolyte layer is ≥1.2×10⁻⁶. -3 S / cm, electrochemical window ≥5.0V; the semi-solid battery retains ≥92% capacity after 500 cycles at 4C rate, and / or retains ≥85% capacity at 2C rate discharge at -20℃.

[0019] Furthermore, it also includes a soft-pack shell and a phase change thermal management module attached to the outside of the soft-pack shell; the positive electrode, the composite solid electrolyte layer, and the negative electrode are sequentially stacked and then encapsulated in the soft-pack shell using a Z-shaped stacking process;

[0020] Preferably, the phase change thermal management module is composed of a composite system of polyethylene glycol-8000 and expanded graphite.

[0021] A process for fabricating a semi-solid-state battery, the process being used based on the aforementioned semi-solid-state battery, includes the following steps:

[0022] S1. Preparation of positive electrode sheet: High-nickel ternary material modified by lithium compound coating is mixed with conductive agent, binder and inorganic solid electrolyte powder to form positive electrode slurry, which is coated on positive electrode current collector, and then dried and rolled to obtain positive electrode sheet.

[0023] S2. Preparation of negative electrode sheet: The pre-lithiated porous silicon / hard carbon composite material is mixed with conductive agent, binder and inorganic solid electrolyte powder to form negative electrode slurry, which is coated on negative electrode current collector and then dried and rolled to obtain negative electrode sheet.

[0024] S3. Preparation of composite solid electrolyte layer: Dissolve polymer matrix, inorganic solid electrolyte, lithium salt and interface modifier in solvent to form precursor solution, and form composite solid electrolyte layer after casting and drying.

[0025] S4. Cell assembly: The positive electrode, composite solid electrolyte layer and negative electrode are stacked together to form a cell and then packaged.

[0026] Furthermore, the lithium compound coating modification process in step S1 includes: dispersing the high-nickel ternary material in a solvent, adding the lithium compound precursor to react, and then filtering, drying and calcining.

[0027] Preferably, the lithium compound precursor is lithium dihydrogen phosphate, and the calcination temperature is 500°C.

[0028] Furthermore, the pre-lithiation process described in step S2 includes: mixing and dispersing porous silicon and hard carbon in a solvent, adding lithium metal powder, stirring and reacting under inert gas protection, and then filtering and drying.

[0029] Preferably, the stirring reaction is carried out at a temperature of 40°C for 3 hours.

[0030] Furthermore, the packaging described in step S4 is a soft-pack packaging, in which a small amount of electrolyte is injected into the cell before or during packaging, and the amount of electrolyte injected is 1-2% of the battery mass;

[0031] Preferably, the electrolyte is a 0.1 mol / L LiTFSI / dimethyl carbonate solution;

[0032] Step S4 is followed by formation and aging steps. The formation process is as follows: first, charge at a constant current of 0.05C to 3.6V, let stand, and then charge at a constant current of 0.1C to 4.3V. The aging conditions are aging at 45℃ for 24 hours.

[0033] (III) Beneficial Effects

[0034] Compared with the prior art, the present invention provides a semi-solid-state battery and its preparation process, which has the following beneficial effects:

[0035] The composite solid-state electrolyte system offers significant advantages: This invention employs a PEO-LLZO-LiTFSI ternary composite solid-state electrolyte. The introduction of LLZO nanoparticles significantly enhances the ionic conductivity of the electrolyte, while the perfluorooctyltriethoxysilane interface modifier effectively improves the interfacial compatibility between the electrolyte and the electrode. The room temperature ionic conductivity is ≥1.2×10⁻⁶. -3 S / cm, interface impedance reduced to 100 Ω·cm 2 Furthermore, the electrochemical window is widened to above 5.0V, making it compatible with high-nickel ternary cathode materials.

[0036] Synergistic optimization of electrode structure and interface regulation: The positive electrode active material is modified by LiPO3 coating, which effectively inhibits the dissolution of transition metals and structural collapse of high-nickel ternary materials; the negative electrode adopts pre-lithiation porous silicon / hard carbon composite material, the pre-lithiation treatment makes up for the initial capacity loss of silicon-based materials, and the porous structure alleviates volume expansion; LLZO solid electrolyte powder is added to the electrode to construct ion transport channels and further reduce the electrode-electrolyte interface impedance.

[0037] The preparation process is low-energy and compatible with large-scale production: The preparation process of this invention adopts low-energy steps such as low-temperature drying and room-temperature stirring, avoiding complex processes such as high-temperature sintering and high-pressure molding, thus reducing production costs; at the same time, the process is highly compatible with existing lithium-ion battery mass production equipment, making it easy to achieve large-scale mass production.

[0038] Excellent compatibility between soft-pack packaging and thermal management: The PA / Al / PP composite aluminum-plastic film soft-pack packaging, combined with precise heat sealing process parameters, ensures the sealing performance; the phase change thermal management module attached to the outside can quickly absorb the heat during high-rate charging and discharging, keeping the battery temperature within the range of 35-45℃, which significantly improves the cycle stability and safety of the battery.

[0039] The battery's overall performance is precisely matched to the needs of drones: The semi-solid-state battery of this invention maintains a capacity retention rate of ≥95% at 2C rate, which can meet the high-rate power supply requirements of drones for rapid take-off and high-speed flight; after 500 cycles at 4C rate, the capacity retention rate is ≥92%, ensuring the cycle life of drones for long-term operation; within a wide temperature range of -20℃ to 60℃, the capacity retention rate at 2C rate is ≥85%, which is suitable for complex environments such as high-altitude low-temperature and high-temperature operations of drones; and the thermal runaway temperature is increased to above 200℃, which is significantly safer than traditional liquid batteries. At the same time, the energy density reaches above 400Wh / kg, and the weight is 20-25% lighter than traditional drone batteries of the same capacity, achieving a balance between lightweight and long endurance, which is fully matched with the application needs of various drones such as industrial and consumer drones. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Example

[0043] like Figure 1 As shown, an embodiment of the present invention provides a semi-solid-state battery comprising a positive electrode, a negative electrode, and a composite solid electrolyte layer; the composite solid electrolyte layer is a ternary composite system comprising a polymer matrix, an inorganic solid electrolyte, and a lithium salt, and further comprising an interface modifier; the positive electrode and / or the negative electrode contain the same inorganic solid electrolyte powder as that in the composite solid electrolyte layer; the positive electrode active material of the positive electrode is a high-nickel ternary material modified by lithium compound coating; the negative electrode active material of the negative electrode is a porous silicon / hard carbon composite material pre-lithiated.

[0044] Specifically, the semi-solid battery includes a positive electrode, a negative electrode, a composite solid electrolyte layer, a soft-pack shell, and a phase change thermal management module. The positive electrode, the composite solid electrolyte layer, and the negative electrode are stacked in sequence and then encapsulated in the soft-pack shell using a Z-shaped stacking process. The phase change thermal management module is attached to the outside of the soft-pack shell.

[0045] The positive electrode sheet is made by mixing positive electrode active material, conductive agent, binder and solid electrolyte powder in a mass ratio of 85-92:3-6:2-4:3-5, wherein the positive electrode active material is LiNi. 0.9 Co 0.05 Mn 0.05 O2 (NCM90505) high-nickel ternary material, its surface modified with LiPO3 coating, the coating thickness is 3-5nm; the conductive agent is a carbon nanotube-graphene composite conductive agent (mass ratio 4:1); the binder is polyvinylidene fluoride (PVDF); the solid electrolyte powder is Li7La3Zr2O. 12 (LLZO) nanoparticles with a particle size of 50-100 nm;

[0046] The negative electrode sheet is made by mixing negative electrode active material, conductive agent, binder and solid electrolyte powder in a mass ratio of 88-94:2-5:2-3:2-4. The negative electrode active material is a pre-lithiated porous silicon / hard carbon composite material (mass ratio 35:65), with a pre-lithiation degree of 6-8% and a porous silicon porosity of 40-50%. The conductive agent is superconducting carbon black (Super P). The binder is a composite binder of styrene-butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC) (mass ratio 2:1). The solid electrolyte powder is the same as that used in the positive electrode sheet.

[0047] The composite solid electrolyte layer is a ternary composite system of "polymer matrix-inorganic solid electrolyte-lithium salt" with a thickness of 20-30 μm. It is composed of the following components by mass fraction: polyethylene oxide (PEO) 25-35%, LLZO nanoparticles 40-50%, LiTFSI 15-20%, and interface modifier 1-3%. The interface modifier is perfluorooctyltriethoxysilane, which can improve the interfacial compatibility between the composite solid electrolyte and the electrode. The room temperature ionic conductivity of the composite solid electrolyte layer is ≥1.2×10⁻⁶. -3 S / cm, electrochemical window ≥5.0V;

[0048] The soft-pack outer shell is a PA / Al / PP three-layer composite aluminum-plastic film with a thickness of 90-110μm. It is packaged using a heat-sealing process with a heat-sealing temperature of 180-200℃, a heat-sealing pressure of 0.3-0.5MPa, and a heat-sealing time of 2-3s to ensure the sealing performance.

[0049] In some embodiments, the interface modifier is perfluorooctyltriethoxysilane; in the composite solid electrolyte layer, the polymer matrix is ​​polyethylene oxide, and the inorganic solid electrolyte is Li7La3Zr2O. 12 The nanoparticles, wherein the lithium salt is LiTFSI; preferably, the composite solid electrolyte layer is composed of the following components by mass fraction: 25-35% polyethylene oxide, Li7La3Zr2O 12 40-50% nanoparticles, 15-20% LiTFSI, and 1-3% perfluorooctyltriethoxysilane.

[0050] In some embodiments, the high-nickel ternary material is LiNi. 0.9 Co 0.05 Mn 0.05 O2, wherein the lithium compound is LiPO3, and the coating thickness is 3-5 nm; preferably, the positive electrode sheet is composed of a positive electrode active material, a conductive agent, a binder, and Li7La3Zr2O. 12 The nanoparticles are prepared by mixing them in a mass ratio of 85-92:3-6:2-4:3-5.

[0051] In some embodiments, in the pre-lithiated porous silicon / hard carbon composite material, the mass ratio of porous silicon to hard carbon is 35:65, the degree of pre-lithiation is 6-8%, and the porosity of the porous silicon is 40-50%. Preferably, the negative electrode sheet is composed of a negative electrode active material, a conductive agent, a binder, and Li7La3Zr2O. 12 The nanoparticles are prepared by mixing them in a mass ratio of 88-94:2-5:2-3:2-4.

[0052] In some embodiments, the room temperature ionic conductivity of the composite solid electrolyte layer is ≥1.2×10⁻⁶. -3S / cm, electrochemical window ≥5.0V; the semi-solid battery retains ≥92% capacity after 500 cycles at 4C rate, and / or retains ≥85% capacity at 2C rate discharge at -20℃.

[0053] In some embodiments, the device further includes a soft-pack housing and a phase change thermal management module attached to the outside of the soft-pack housing; the positive electrode, the composite solid electrolyte layer, and the negative electrode are sequentially stacked and then encapsulated in the soft-pack housing using a Z-shaped stacking process;

[0054] Preferably, the phase change thermal management module is composed of a composite system of polyethylene glycol-8000 and expanded graphite.

[0055] like Figure 1 As shown, a fabrication process for a semi-solid-state battery, based on the aforementioned semi-solid-state battery, includes the following steps:

[0056] S1. Preparation of positive electrode sheet: High-nickel ternary material modified by lithium compound coating is mixed with conductive agent, binder and inorganic solid electrolyte powder to form positive electrode slurry, which is coated on positive electrode current collector, and then dried and rolled to obtain positive electrode sheet.

[0057] S2. Preparation of negative electrode sheet: The pre-lithiated porous silicon / hard carbon composite material is mixed with conductive agent, binder and inorganic solid electrolyte powder to form negative electrode slurry, which is coated on negative electrode current collector and then dried and rolled to obtain negative electrode sheet.

[0058] S3. Preparation of composite solid electrolyte layer: Dissolve polymer matrix, inorganic solid electrolyte, lithium salt and interface modifier in solvent to form precursor solution, and form composite solid electrolyte layer after casting and drying.

[0059] S4. Cell assembly: The positive electrode, composite solid electrolyte layer and negative electrode are stacked together to form a cell and then packaged.

[0060] like Figure 1 As shown, in some embodiments, the lithium compound coating modification process in step S1 includes: dispersing the high-nickel ternary material in a solvent, adding the lithium compound precursor to react, and then filtering, drying and calcining.

[0061] Preferably, the lithium compound precursor is lithium dihydrogen phosphate, and the calcination temperature is 500°C.

[0062] like Figure 1 As shown, in some embodiments, the pre-lithiation process in step S2 includes: mixing and dispersing porous silicon and hard carbon in a solvent, adding lithium metal powder, stirring and reacting under inert gas protection, and then filtering and drying.

[0063] Preferably, the stirring reaction is carried out at a temperature of 40°C for 3 hours.

[0064] like Figure 1 As shown, in some embodiments, the packaging in step S4 is a soft-pack packaging, in which a small amount of electrolyte is injected into the cell before or during packaging, and the amount of electrolyte injected is 1-2% of the battery mass;

[0065] Preferably, the electrolyte is a 0.1 mol / L LiTFSI / dimethyl carbonate solution;

[0066] Step S4 is followed by formation and aging steps. The formation process is as follows: first, charge at a constant current of 0.05C to 3.6V, let stand, and then charge at a constant current of 0.1C to 4.3V. The aging conditions are aging at 45℃ for 24 hours.

[0067] The fabrication process of semi-solid-state batteries includes the following steps:

[0068] 1) Preparation of positive electrode sheet:

[0069] (1) NCM90505 high-nickel ternary material was added to an ethanol solution and ultrasonically dispersed for 30 min. Then, LiPO3 precursor (lithium dihydrogen phosphate) was added and stirred at 60 °C for 2 h. After filtration and drying, it was calcined at 500 °C for 3 h to obtain LiPO3 coated modified positive electrode active material.

[0070] (2) Weigh the LiPO3-coated modified positive electrode active material, carbon nanotube-graphene composite conductive agent, PVDF binder and LLZO nanopowder according to the mass ratio of 85-92:3-6:2-4:3-5, add N-methylpyrrolidone (NMP) solvent, and stir at high speed at 25°C for 4 hours to prepare a uniform positive electrode slurry.

[0071] (3) The positive electrode slurry is coated onto the surface of the aluminum foil current collector with a coating thickness of 80-100 μm. It is pre-dried at 80℃ for 2 h, and then dried at 120℃ under vacuum for 12 h. After that, it is rolled (compacted density 3.5-3.8 g / cm³). 3 Cut the electrode to obtain the positive electrode sheet;

[0072] 2) Preparation of negative electrode sheet:

[0073] (1) Porous silicon and hard carbon were mixed at a mass ratio of 35:65 and added to a hexane solution. The mixture was ultrasonically dispersed for 20 min, and then lithium metal powder (pre-lithiation agent) was added. The mixture was stirred and reacted at 40°C for 3 h under inert gas protection. After filtration and drying, a pre-lithiation porous silicon / hard carbon composite material was obtained.

[0074] (2) Weigh the pre-lithiated porous silicon / hard carbon composite material, Super P conductive agent, SBR-CMC composite binder and LLZO nanoparticles according to the mass ratio of 88-94:2-5:2-3:2-4, add deionized water, and stir at high speed for 6 hours at 25°C to prepare a uniform negative electrode slurry.

[0075] (3) The negative electrode slurry is coated onto the surface of the copper foil current collector with a coating thickness of 90-110 μm. It is pre-dried at 60℃ for 3 h, and then dried at 100℃ under vacuum for 12 h. After rolling (compacted density 1.6-1.8 g / cm³), the negative electrode slurry is applied to the surface of the copper foil current collector. 3 Cutting and trimming yields the negative electrode sheet;

[0076] 3) Preparation of composite solid electrolyte layer:

[0077] (1) Weigh PEO, LLZO nanoparticles, LiTFSI and perfluorooctyltriethoxysilane according to mass fractions of 25-35%, 40-50%, 15-20% and 1-3%, add them to acetonitrile solvent, stir and dissolve at 60°C to form a uniform electrolyte precursor solution.

[0078] (2) The electrolyte precursor solution was cast and coated on a polytetrafluoroethylene substrate with a coating thickness of 20-30 μm. It was dried at 40°C for 6 h, and then dried at 80°C under vacuum for 12 h. The substrate was then peeled off to obtain a composite solid electrolyte layer.

[0079] 4) Cell assembly and soft-pack packaging:

[0080] (1) In an inert gas glove box (water and oxygen content ≤1ppm), the positive electrode, composite solid electrolyte layer and negative electrode are stacked in sequence and assembled into a battery cell using a Z-shaped stacking process. The tabs adopt a full tab structure to reduce the electronic transmission impedance.

[0081] (2) Place the assembled battery cell into a PA / Al / PP composite aluminum-plastic film soft package and encapsulate it using a heat sealing process. The heat sealing temperature is 180-200℃, the heat sealing pressure is 0.3-0.5MPa, the heat sealing time is 2-3s, and a liquid injection port is reserved.

[0082] (3) Inject a small amount of electrolyte (LiTFSI / dimethyl carbonate (DMC), concentration 0.1mol / L) through the injection port. The injection amount is 1-2% of the battery mass. This is used to wet the interface and reduce the interface impedance. Then, perform secondary heat sealing to complete the soft pack packaging.

[0083] 5) Formation and aging:

[0084] (1) The packaged soft-pack battery cell is subjected to formation treatment. The formation process is as follows: constant current charging at 0.05C to 3.6V, resting for 30min, then constant current charging at 0.1C to 4.3V, and resting for 20min.

[0085] (2) After formation, the cells were aged at 45°C for 24 hours to obtain a semi-solid cell;

[0086] 6) Thermal management module assembly:

[0087] A phase change material (PEG-8000 and expanded graphite composite system) is encapsulated in a flexible polyimide film to form a phase change thermal management module, which is then tightly attached to the outside of the soft-pack battery casing to complete the overall fabrication.

[0088] Example 1: A fabrication process for a semi-solid-state battery, the specific steps of which are as follows:

[0089] Preparation of S1 positive electrode sheet:

[0090] (1) NCM90505 high-nickel ternary material was added to an ethanol solution and ultrasonically dispersed for 30 min. Then, LiPO3 precursor was added and stirred at 60 °C for 2 h. After filtration and drying, it was calcined at 500 °C for 3 h to obtain LiPO3 coated modified positive electrode active material.

[0091] (2) Weigh the above positive electrode active material, carbon nanotube-graphene composite conductive agent, PVDF binder and LLZO nanopowder in a mass ratio of 88:5:3:4, add NMP solvent, and stir at high speed at 25°C for 4 hours to prepare positive electrode slurry.

[0092] (3) The positive electrode slurry was coated onto the surface of the aluminum foil current collector with a coating thickness of 90 μm. It was pre-dried at 80°C for 2 h, and then dried at 120°C under vacuum for 12 h. After rolling (compacted density 3.6 g / cm³), the slurry was then rolled. 3 Cut the electrode to obtain the positive electrode sheet;

[0093] Preparation of S2 negative electrode sheet:

[0094] (1) Porous silicon and hard carbon were mixed at a mass ratio of 35:65 and added to a hexane solution. The mixture was ultrasonically dispersed for 20 min, and then lithium metal powder was added. The mixture was stirred and reacted at 40°C for 3 h under inert gas protection. After filtration and drying, a pre-lithiated porous silicon / hard carbon composite material was obtained.

[0095] (2) Weigh the above-mentioned negative electrode active material, Super P conductive agent, SBR-CMC composite binder and LLZO nanoparticles in a mass ratio of 91:3:3:3, add deionized water, and stir at high speed for 6 hours at 25°C to prepare negative electrode slurry.

[0096] (3) The negative electrode slurry was coated onto the surface of the copper foil current collector with a coating thickness of 100 μm. It was pre-dried at 60°C for 3 h, and then dried at 100°C under vacuum for 12 h. After rolling (compacted density 1.7 g / cm³), the negative electrode slurry was applied to the surface of the copper foil current collector. 3 Cutting and trimming yields the negative electrode sheet;

[0097] Preparation of S3 composite solid electrolyte layer:

[0098] (1) Weigh PEO, LLZO nanoparticles, LiTFSI and perfluorooctyltriethoxysilane in mass fractions of 30%, 45%, 18% and 2%, respectively, add them to acetonitrile solvent, stir and dissolve at 60°C to form an electrolyte precursor solution.

[0099] (2) The electrolyte precursor solution was cast and coated onto a polytetrafluoroethylene substrate with a coating thickness of 25 μm. It was dried at 40 °C for 6 h, and then dried at 80 °C under vacuum for 12 h. The substrate was then peeled off to obtain a composite solid electrolyte layer. The room temperature ionic conductivity was measured to be 1.5 × 10⁻⁶. -3 S / cm, electrochemical window is 5.2V;

[0100] S4 cell assembly and soft-pack packaging:

[0101] (1) In an inert gas glove box, the positive electrode, composite solid electrolyte layer and negative electrode are stacked in sequence, and the Z-shaped stack is assembled into a battery cell, adopting a full tab structure;

[0102] (2) Place the battery cell into a PA / Al / PP composite aluminum-plastic film soft package and heat seal it for 2.5s at 190℃ and 0.4MPa, leaving a liquid injection port;

[0103] (3) Inject 0.1 mol / L LiTFSI / DMC electrolyte (the injection amount is 1.5% of the battery mass), and heat seal again;

[0104] S5 formation and aging: Charged to 3.6V at a constant current of 0.05C and left to stand for 30 minutes; charged to 4.3V at a constant current of 0.1C and left to stand for 20 minutes; aged at 45℃ for 24 hours to obtain a semi-solid-state battery.

[0105] Example 2: A fabrication process for a semi-solid-state battery, the specific steps of which are as follows:

[0106] Preparation of S1 positive electrode sheet: LiPO3-coated modified NCM905O5, carbon nanotube-graphene composite conductive agent, PVDF, and LLZO nanoparticles were weighed in a mass ratio of 85:6:4:5. The remaining steps were the same as in Example 1; the compacted density after rolling was 3.5 g / cm³. 3 ;

[0107] Preparation of S2 negative electrode sheet: Pre-lithiated porous silicon / hard carbon composite material, Super P, SBR-CMC, and LLZO nanoparticles were weighed in a mass ratio of 88:5:3:4. The remaining steps were the same as in Example 1. The compacted density after rolling was 1.6 g / cm³. 3 ;

[0108] Preparation of S3 composite solid electrolyte layer: PEO, LLZO nanoparticles, LiTFSI, and perfluorooctyltriethoxysilane were weighed at mass fractions of 25%, 50%, 20%, and 1%, respectively. The remaining steps were the same as in Example 1. The room temperature ionic conductivity was 1.2 × 10⁻⁶. -3 S / cm, electrochemical window is 5.0V;

[0109] S4 cell assembly and soft-pack packaging: heat sealing temperature 180℃, pressure 0.3MPa, time 2s, electrolyte injection amount 1.0%, the remaining steps are the same as in Example 1.

[0110] Example 3: A fabrication process for a semi-solid-state battery, the specific steps of which are as follows:

[0111] Preparation of S1 positive electrode sheet: LiPO3-coated modified NCM905O5, carbon nanotube-graphene composite conductive agent, PVDF, and LLZO nanoparticles were weighed in a mass ratio of 92:3:2:3. The remaining steps were the same as in Example 1. The compacted density after rolling was 3.8 g / cm³. 3 ;

[0112] Preparation of S2 negative electrode sheet: Pre-lithiated porous silicon / hard carbon composite material, Super P, SBR-CMC, and LLZO nanoparticles were weighed in a mass ratio of 94:2:2:2, and the remaining steps were the same as in Example 1; the compacted density after rolling was 1.8 g / cm³. 3 ;

[0113] Preparation of S3 composite solid electrolyte layer: PEO, LLZO nanoparticles, LiTFSI, and perfluorooctyltriethoxysilane were weighed at mass fractions of 35%, 40%, 15%, and 3%, respectively. The remaining steps were the same as in Example 1. The room temperature ionic conductivity was 1.8 × 10⁻⁶. -3 S / cm, electrochemical window is 5.3V;

[0114] S4 cell assembly and soft-pack packaging: heat sealing temperature 200℃, pressure 0.5MPa, time 3s, electrolyte injection amount 2.0%, the remaining steps are the same as in Example 1.

[0115] The performance of the semi-solid-state batteries prepared in Examples 1 to 3 above was tested, and the test results are shown in the table below:

[0116] Test Project Example 1 Example 2 Example 3 Room temperature ionic conductivity (S / cm) <![CDATA[1.5×10 -3 ]]> <![CDATA[1.2×10 -3 ]]> <![CDATA[1.8×10 -3 ]]> <![CDATA[Interface impedance (Ω·cm 2 )]]> 85 98 72 2C rate discharge capacity retention (relative to 0.2C) 96.2% 95.0% 97.1% Capacity retention after 500 4C cycles 92.5% 92.0% 93.3% -20℃ low-temperature 2C discharge capacity retention (relative to room temperature 0.2C) 86.3% 85.0% 87.5% Thermal runaway temperature (°C) 215 208 222 Energy density (Wh / kg) 412 405 420

[0117] Test results show that the semi-solid battery prepared by this invention has excellent ion transport performance, interface stability, high rate cycling performance and wide temperature range adaptability, significantly improved thermal runaway temperature, energy density of over 400Wh / kg and obvious lightweight advantages, fully meeting the stringent battery requirements of various drone scenarios such as industrial drones, consumer drones, and agricultural drones; at the same time, the preparation process is low-energy consumption and easy to scale up, with broad industrialization prospects.

[0118] Compared with the prior art, the present invention provides a semi-solid-state battery and its preparation process, which has the following beneficial effects:

[0119] The composite solid-state electrolyte system offers significant advantages: This invention employs a PEO-LLZO-LiTFSI ternary composite solid-state electrolyte. The introduction of LLZO nanoparticles significantly enhances the ionic conductivity of the electrolyte, while the perfluorooctyltriethoxysilane interface modifier effectively improves the interfacial compatibility between the electrolyte and the electrode. The room temperature ionic conductivity is ≥1.2×10⁻⁶. -3 S / cm, interface impedance reduced to 100 Ω·cm 2 Furthermore, the electrochemical window is widened to above 5.0V, making it compatible with high-nickel ternary cathode materials.

[0120] Synergistic optimization of electrode structure and interface regulation: The positive electrode active material is modified by LiPO3 coating, which effectively inhibits the dissolution of transition metals and structural collapse of high-nickel ternary materials; the negative electrode adopts pre-lithiation porous silicon / hard carbon composite material, the pre-lithiation treatment makes up for the initial capacity loss of silicon-based materials, and the porous structure alleviates volume expansion; LLZO solid electrolyte powder is added to the electrode to construct ion transport channels and further reduce the electrode-electrolyte interface impedance.

[0121] The preparation process is low-energy and compatible with large-scale production: The preparation process of this invention adopts low-energy steps such as low-temperature drying and room-temperature stirring, avoiding complex processes such as high-temperature sintering and high-pressure molding, thus reducing production costs; at the same time, the process is highly compatible with existing lithium-ion battery mass production equipment, making it easy to achieve large-scale mass production.

[0122] Excellent compatibility between soft-pack packaging and thermal management: The PA / Al / PP composite aluminum-plastic film soft-pack packaging, combined with precise heat sealing process parameters, ensures the sealing performance; the phase change thermal management module attached to the outside can quickly absorb the heat during high-rate charging and discharging, keeping the battery temperature within the range of 35-45℃, which significantly improves the cycle stability and safety of the battery.

[0123] The battery's overall performance is precisely matched to the needs of drones: The semi-solid-state battery of this invention maintains a capacity retention rate of ≥95% at 2C rate, which can meet the high-rate power supply requirements of drones for rapid take-off and high-speed flight; after 500 cycles at 4C rate, the capacity retention rate is ≥92%, ensuring the cycle life of drones for long-term operation; within a wide temperature range of -20℃ to 60℃, the capacity retention rate at 2C rate is ≥85%, which is suitable for complex environments such as high-altitude low-temperature and high-temperature operations of drones; and the thermal runaway temperature is increased to above 200℃, which is significantly safer than traditional liquid batteries. At the same time, the energy density reaches above 400Wh / kg, and the weight is 20-25% lighter than traditional drone batteries of the same capacity, achieving a balance between lightweight and long endurance, which is fully matched with the application needs of various drones such as industrial and consumer drones.

[0124] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A semi-solid-state battery, characterized in that: It includes positive electrode plates, negative electrode plates, and a composite solid electrolyte layer; The composite solid electrolyte layer is a ternary composite system comprising a polymer matrix, an inorganic solid electrolyte, and a lithium salt, and also includes an interface modifier. The positive electrode and / or the negative electrode contain the same inorganic solid electrolyte powder as that in the composite solid electrolyte layer; The positive electrode active material of the positive electrode sheet is a high-nickel ternary material modified by lithium compound coating; The negative electrode active material of the negative electrode sheet is a porous silicon / hard carbon composite material that has undergone pre-lithiation treatment.

2. The semi-solid-state battery according to claim 1, characterized in that: The interface modifier is perfluorooctyltriethoxysilane; in the composite solid electrolyte layer, the polymer matrix is ​​polyethylene oxide, and the inorganic solid electrolyte is Li7La3Zr2O. 12 The nanoparticles, wherein the lithium salt is LiTFSI; the composite solid electrolyte layer is composed of the following components by mass fraction: 25-35% polyethylene oxide, Li7La3Zr2O 12 40-50% nanoparticles, 15-20% LiTFSI, and 1-3% perfluorooctyltriethoxysilane.

3. A semi-solid-state battery according to claim 1, characterized in that: The high-nickel ternary material is LiNi. 0.9 Co 0.05 Mn 0.05 O2, wherein the lithium compound is LiPO3, and the coating thickness is 3-5 nm; the positive electrode sheet is composed of positive electrode active material, conductive agent, binder and Li7La3Zr2O. 12 The nanoparticles are prepared by mixing them in a mass ratio of 85-92:3-6:2-4:3-5.

4. A semi-solid-state battery according to claim 1, characterized in that: In the pre-lithiated porous silicon / hard carbon composite material, the mass ratio of porous silicon to hard carbon is 35:65, the degree of pre-lithiation is 6-8%, and the porosity of the porous silicon is 40-50%; the negative electrode sheet is composed of negative electrode active material, conductive agent, binder, and Li7La3Zr2O. 12 The nanoparticles are prepared by mixing them in a mass ratio of 88-94:2-5:2-3:2-4.

5. A semi-solid-state battery according to claim 1, characterized in that: The room temperature ionic conductivity of the composite solid electrolyte layer is ≥1.2×10⁻⁶. -3 S / cm, electrochemical window ≥5.0V; the semi-solid battery retains ≥92% capacity after 500 cycles at 4C rate, and / or retains ≥85% capacity at 2C rate discharge at -20℃.

6. A semi-solid-state battery according to claim 1, characterized in that: It also includes a soft-pack shell and a phase change thermal management module attached to the outside of the soft-pack shell; the positive electrode, the composite solid electrolyte layer, and the negative electrode are stacked in sequence and then encapsulated in the soft-pack shell using a Z-shaped stacking process; The phase change thermal management module is composed of a composite system of polyethylene glycol-8000 and expanded graphite.

7. A process for preparing a semi-solid-state battery, the process being used based on a semi-solid-state battery according to any one of claims 1-6, characterized in that: Includes the following steps: S1. Preparation of positive electrode sheet: High-nickel ternary material modified by lithium compound coating is mixed with conductive agent, binder and inorganic solid electrolyte powder to form positive electrode slurry, which is coated on positive electrode current collector, and then dried and rolled to obtain positive electrode sheet. S2. Preparation of negative electrode sheet: The pre-lithiated porous silicon / hard carbon composite material is mixed with conductive agent, binder and inorganic solid electrolyte powder to form negative electrode slurry, which is coated on negative electrode current collector and then dried and rolled to obtain negative electrode sheet. S3. Preparation of composite solid electrolyte layer: Dissolve polymer matrix, inorganic solid electrolyte, lithium salt and interface modifier in solvent to form precursor solution, and form composite solid electrolyte layer after casting and drying. S4. Cell assembly: The positive electrode, composite solid electrolyte layer and negative electrode are stacked together to form a cell and then packaged.

8. The fabrication process of a semi-solid-state battery according to claim 7, characterized in that: The lithium compound coating modification process in step S1 includes: dispersing high-nickel ternary materials in a solvent, adding lithium compound precursors to react, and then filtering, drying and calcining. The lithium compound precursor is lithium dihydrogen phosphate, and the calcination temperature is 500°C.

9. The fabrication process of a semi-solid-state battery according to claim 7, characterized in that: The pre-lithiation process described in step S2 includes: mixing and dispersing porous silicon and hard carbon in a solvent, adding lithium metal powder, stirring and reacting under inert gas protection, and then filtering and drying. The stirring reaction was carried out at a temperature of 40°C for 3 hours.

10. The fabrication process of a semi-solid-state battery according to claim 7, characterized in that: The packaging described in step S4 is a soft-pack packaging. Before or during packaging, a small amount of electrolyte is injected into the cell. The amount of electrolyte injected is 1-2% of the battery mass. The electrolyte is a 0.1 mol / L LiTFSI / dimethyl carbonate solution; Step S4 is followed by formation and aging steps. The formation process is as follows: first, charge at a constant current of 0.05C to 3.6V, let stand, and then charge at a constant current of 0.1C to 4.3V. The aging conditions are aging at 45℃ for 24 hours.

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