Silane modified zirconium phosphate electrolyte additive and preparation method thereof
By treating nano-zirconium phosphate using a hydrothermal method and an acoustic-electric coupling module, a silane-modified zirconium phosphate electrolyte additive was prepared, which solved the adaptability problem of inorganic filler systems and improved the thermal safety and long-cycle stability of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FUJIAN RUISEN CHEM
- Filing Date
- 2026-02-10
- Publication Date
- 2026-05-08
AI Technical Summary
Existing electrolyte additives cannot adapt to inorganic filler systems, leading to accelerated LiPF6 decomposition, rapid capacity decay, low interfacial film modulus, inability to suppress lithium dendrite penetration and high volume expansion, and difficulty in extending modified groups into the zirconium phosphate layer.
Nano-zirconium phosphate was prepared by hydrothermal method and then processed in a surface modification device using microwave stirring and an acoustic-electric coupling module. Silane coupling agents were grafted and modified under microwave and ultrasonic conditions to form a hydrophobic organic layer, improving dispersibility and interfacial compatibility.
It effectively inhibits LiPF6 decomposition, improves battery thermal safety and long-cycle stability, and the uniform embedding of nano-zirconium phosphate into the SEI film forms a rigid skeleton, reducing capacity loss and improving battery performance.
Smart Images
Figure CN121990541A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrolyte additives, and in particular to a silane-modified zirconium phosphate electrolyte additive and its preparation method. Background Technology
[0002] While traditional film-forming additives such as vinylene carbonate (VC) and fluoroethylene carbonate (FEC) can effectively optimize the SEI / CEI film structure and improve interfacial stability, their effects are limited to the electrode surface and cannot inhibit the thermal decomposition reaction of LiPF6 above 60°C at the source. The PF5 generated by the thermal dissociation of LiPF6 reacts with trace amounts of water to form HF, triggering the dissolution of the cathode transition metal and interfacial corrosion. This results in a capacity loss of ≥5% after 7 days of high-temperature storage, which has become a common bottleneck in high-energy-density battery systems such as high-nickel ternary batteries.
[0003] The current mainstream solution in the industry to suppress the decomposition of LiPF6 is to use soluble organosilicon / phosphorus compounds (such as TTSPi and TMSNCS). However, these additives undergo irreversible coordination reactions with PF5 through Si-O / P / B bonds (such as TTSPi + PF5 → product), and are continuously consumed and cannot be regenerated. Under long-term storage at 60°C (>14 days) or operating conditions above 80°C, the decomposition of LiPF6 accelerates after the additives are exhausted, and the capacity decay curve shows a "slow at first and then steep" characteristic, which is difficult to meet the 10-year lifespan requirement of automotive batteries.
[0004] Meanwhile, to avoid interfacial compatibility risks with inorganic fillers (such as adsorption deactivation, agglomeration and sedimentation), the industry generally adopts a pure organic additive system. However, this sacrifices the key performance gains brought by inorganic materials: lacking the high heat capacity and physical barrier capabilities of fillers such as Al2O3 and Mg(OH)2, the effect of suppressing temperature rise in the early stage of thermal runaway is limited; lacking the "rigid framework" formed by particles such as SiO2 and zirconium phosphate in SEI / CEI, the interfacial film modulus is low (<1 GPa), making it difficult to suppress lithium dendrite penetration and film rupture under high volume expansion; at the same time, it loses the non-consumable buffering effect of inorganic surface P–OH / Al–OH groups on HF, and acidity rebound accelerates cathode corrosion after long-term storage. These deficiencies result in a significant performance ceiling for batteries in terms of thermal safety, long cycle life (especially silicon anode systems), and wide temperature range adaptability.
[0005] Zirconium phosphate possesses a tunable interlayer structure, allowing it to embed into SEI / CEI films to form a rigid mechanical framework, effectively suppressing lithium dendrite penetration and film rupture under high volume expansion. Simultaneously, its electrochemical inertness ensures stability within high voltage windows, making it suitable for high-nickel / high-voltage systems. Therefore, zirconium phosphate shows potential as an electrolyte additive.
[0006] However, zirconium phosphate itself is prone to forming hydrogen bonds with solvents due to the abundant P-OH groups on its surface, which leads to severe agglomeration. It settles after standing for 24 hours (settling rate >70%) and cannot form a stable dispersion system. When applied directly, the micron-sized agglomerates formed by zirconium phosphate are difficult to embed into the SEI / CEI film. Instead, they may block the electrode pores, increase the interfacial impedance, and thus affect the battery performance.
[0007] Therefore, zirconium phosphate needs further improvement to make it adaptable to inorganic filler systems and suppress the decomposition of LiPF6. Summary of the Invention
[0008] The technical problem to be solved by the present invention is to provide a silane-modified zirconium phosphate electrolyte additive and its preparation method, thereby solving the problem that existing electrolyte additives cannot be adapted to inorganic filler systems.
[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a method for preparing a silane-modified zirconium phosphate electrolyte additive, comprising the following steps: S1. The zirconium source and phosphorus source are introduced into a high-pressure synthesis reactor, stirred and mixed thoroughly, and hydrothermally reacted at 160℃~200℃ for 12~24h. The reaction product is centrifuged, washed, filtered and dried to obtain nano-zirconium phosphate. S2. Disperse the nano-zirconium phosphate obtained in S1 in anhydrous ethanol, then pass it into the main chamber of the surface modification device, and add silane coupling agent to the main chamber, so that the mixed solution is initially mixed at 60℃~80℃ under the action of microwave stirring module in the main chamber. S3. After initial mixing, the microwave stirring module continues to run, while the mixed solution at the bottom of the main chamber flows from bottom to top through the acoustic-electric coupling module and then flows back to the main chamber from the top. The mixed solution is modified in the acoustic-electric coupling module under the combined action of electric field and ultrasound. S4. After modification, the mixed solution obtained in S3 is centrifuged and dried to obtain silane-modified zirconium phosphate electrolyte additive.
[0010] In one embodiment, the surface modification apparatus includes; The main body has a central main chamber; The microwave stirring module is located at the top of the main body and extends into the cavity from the top of the main body. It is used to stir the mixed solution in the main cavity and microwave heat it. The acoustic-electric coupling module includes an ultrasonic component, an electric field generating component, and several reaction tubes. The reaction tubes are distributed vertically and spaced apart on the outside of the main body. The bottom and top of the reaction tubes are connected to the main chamber through delivery pipes. The ultrasonic component is correspondingly located on the top of the reaction tubes and is used to sonicate the mixed solution inside the reaction tubes. The electric field generating component is sleeved on the reaction tubes. The electric field generating component has multiple arc-shaped electrodes distributed vertically inside it, with adjacent arc-shaped electrodes having opposite polarities.
[0011] In one embodiment, the electric field generating assembly includes a fixed ring, arc-shaped electrodes, a sliding frame, and an adjustment mechanism. The fixed ring includes an inner ring wall and an outer ring wall, forming a mounting cavity between the inner and outer ring walls. One end of the sliding frame is hinged to the inner ring wall, and the other end of the sliding frame is slidably connected to the outer ring wall. The arc-shaped electrodes are spaced apart within the mounting cavity. The adjustment mechanism is located at both ends of the arc-shaped electrodes and is slidably connected to the side of the sliding frame closer to the outer ring wall. The adjustment mechanism drives the sliding frame to rotate, thereby adjusting the position of the arc-shaped electrodes within the mounting cavity.
[0012] In one embodiment, the adjustment mechanism includes a spacer sliding wall, an adjustment rod, and a connecting rod; an arc-shaped electrode is connected to the middle of the spacer sliding wall, an extension post is provided on one side of the spacer sliding wall along its length, a sliding frame plate is provided with a corresponding sliding groove, and the extension post is slidably connected to the sliding groove; the adjustment rod extends from the outer side of the outer ring wall into the mounting cavity, and the two ends of the connecting rod are respectively hinged to the side of the spacer sliding wall with the extension post and the end of the adjustment rod extending into the mounting cavity.
[0013] In one embodiment, the adjusting rod is a screw, and one end of the adjusting rod extending into the mounting cavity is provided with a rotatable connecting sleeve, and the connecting rod is hinged to the connecting sleeve.
[0014] In one embodiment, the adjusting rod is connected to two connecting rods simultaneously, and the spaced sliding walls connected to adjacent connecting rods are respectively connected to the edges of arc-shaped electrodes of different polarities.
[0015] In one embodiment, the microwave stirring module includes a stirring component, a microwave component, a drive motor, and a drive rod. The drive motor is located at the top of the main body, and the drive rod is connected to the output end of the drive motor and extends into the main cavity. The microwave component extends from the top of the main body into the main cavity and is sleeved on the outer edge of the drive rod. The stirring component is located at the end of the drive rod away from the drive motor and extends upward along the outer wall of the microwave component.
[0016] In one embodiment, the microwave assembly includes a microwave ring wall, a microwave generator, a helical conduit, and a transmission window. The microwave ring wall extends downward from the top of the main chamber. The microwave generator is disposed at the top of the microwave ring wall. A helical conduit is embedded in the microwave ring wall. The transmission window is disposed on the microwave ring wall. The helical conduit conducts the microwaves generated by the microwave generator assembly into the main chamber through the transmission window. The stirring assembly includes a main frame plate, a support plate, a contact plate, and a connecting plate. The middle part of the main frame plate is connected to the drive rod. The support plate extends vertically upward from both ends of the main frame plate. The contact plate extends upward from the middle part of the main frame plate along both sides of the outer edge of the microwave ring wall. The connecting plate is located between the support plate and the contact plate. When the drive rod drives the main frame plate to rotate, the contact plate is driven to rotate around the outer surface of the microwave ring wall.
[0017] In one embodiment, in step S1, the zirconium source includes any one of zirconium oxychloride or zirconium oxynitrate; the phosphorus source includes any one of diammonium hydrogen phosphate or ammonium dihydrogen phosphate; the molar ratio of zirconium source to phosphorus source is 1:1 to 2.5; in step S2, the silane coupling agent includes γ-aminopropyltriethoxysilane, and the amount of silane coupling agent added is 12% to 20% of the mass of nano-zirconium phosphate.
[0018] The present invention also provides a silane-modified zirconium phosphate electrolyte additive prepared by any of the preparation methods described above, with a particle size of 30-80 nm.
[0019] The beneficial effects of this invention are as follows: Zirconium phosphate is difficult to apply directly to electrolytes due to the hydroxyl groups on its surface. Furthermore, if it is modified, the shear force of mechanical stirring is insufficient to remove the van der Waals forces between the zirconium phosphate nanosheets, resulting in the modification groups not being able to penetrate deep into the zirconium phosphate sheets, thus limiting the modification effect.
[0020] The method for preparing silane-modified zirconium phosphate electrolyte additive provided by the present invention first obtains nano-zirconium phosphate with the required particle size range through a hydrothermal method. Then, in a surface modification device, the nano-zirconium phosphate and silane coupling agent are initially mixed under microwave heating and mechanical stirring. Then, through an acoustic-electric coupling module, the mixture is continuously subjected to an electric field and ultrasound, causing the nano-zirconium phosphate to exfoliate agglomerates and efficiently expose the P-OH active sites on the surface of the nano-zirconium phosphate. This allows the modified groups to fully contact and graft onto the active sites, which not only significantly improves the grafting modification effect but also effectively reduces the modification time.
[0021] The silane-modified zirconium phosphate electrolyte additive provided by this invention achieves stable dispersion in the electrolyte by grafting a hydrophobic organic layer onto the surface of zirconium phosphate. Simultaneously, the modified silane-modified zirconium phosphate electrolyte additive retains the chemisorption capacity of the zirconium phosphate structure for HF, while the surface organic layer effectively improves interfacial compatibility, allowing nanosheets to be uniformly embedded in the SEI film to form a "rigid framework," inhibiting dendrite penetration and film rupture, effectively reducing capacity loss, and improving thermal safety and long-cycle stability.
[0022] Other features and beneficial effects of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects of the invention and other beneficial effects may be realized and obtained by means of the structures and / or components pointed out in the description and claims. Attached Figure Description
[0023] Figure 1 This is a flowchart illustrating an embodiment of the present invention; Figure 2 This is a three-dimensional schematic diagram of a surface modification device according to an embodiment of the present invention; Figure 3 for Figure 2 Top view; Figure 4 for Figure 3 Cross-sectional view at point AA; Figure 5 for Figure 4 A magnified view of a section at point I; Figure 6 for Figure 2 The main view; Figure 7 for Figure 6 Cross-sectional view at point BB; Figure 8 This is a three-dimensional schematic diagram of the internal structure of the surface modification device in one embodiment of the present invention; Figure 9 This is a three-dimensional schematic diagram of an electric field generating component in one embodiment of the present invention.
[0024] Label Explanation: 1. Main body; 11. Main chamber; 2. Microwave stirring module; 21. Stirring assembly; 211. Main frame plate; 212. Support plate; 213. Abutment plate; 214. Connecting plate; 22. Microwave assembly; 221. Microwave ring wall; 222. Microwave generator; 223. Spiral conduit; 224. Transmission window; 23. Drive motor; 24. Drive rod; 3. Acousto-electric coupling module; 31. Ultrasonic assembly; 32. Electric field generating assembly; 321. Arc electrode; 322. Fixing ring; 3221. Inner ring wall; 3222. Outer ring wall; 3223. Mounting cavity; 323. Sliding frame plate; 324. Adjustment mechanism; 3241. Spacer sliding wall; 3242. Adjustment rod; 3243. Connecting rod; 3244. Extension column; 3245. Slide groove; 3246. Connecting sleeve; 33. Reaction tube; 34. Delivery pipeline. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. 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.
[0026] In the description of this invention, it should be noted that all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and should not be construed as limiting the invention; it should be further understood that the terms used in this invention should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this invention.
[0027] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.
[0028] Please refer to Figures 1 to 9 A method for preparing a silane-modified zirconium phosphate electrolyte additive, comprising the following steps: S1. The zirconium source and phosphorus source are introduced into a high-pressure synthesis reactor, stirred and mixed thoroughly, and hydrothermally reacted at 160℃~200℃ for 12~24h. The reaction product is centrifuged, washed, filtered and dried to obtain nano-zirconium phosphate. S2. Disperse the nano-zirconium phosphate obtained in S1 in anhydrous ethanol, and then pass it into the main chamber 11 of the surface modification device. Add a silane coupling agent to the main chamber 11, and let the mixed solution be initially mixed at 60℃~80℃ under the action of the microwave stirring module 2 in the main chamber 11. S3. After initial mixing, the microwave stirring module 2 continues to operate, while the mixed solution at the bottom of the main chamber 11 flows from bottom to top through the acoustic-electric coupling module 3 and then flows back to the main chamber 11 from the top. The mixed solution is modified in the acoustic-electric coupling module 3 under the combined action of electric field and ultrasound. S4. After modification, the mixed solution obtained in S3 is centrifuged and dried to obtain silane-modified zirconium phosphate electrolyte additive.
[0029] Preferably, the initial mixing time in step S2 is 0.5 to 1 hour, and the action time of the acoustic-electric coupling module 3 in step S3 is 2 to 5 hours.
[0030] Preferably, in step S3, the electric field strength is 30–50 V / cm; the ultrasonic frequency is 28–40 kHz; and the power density is 200–400 W / L.
[0031] In this embodiment, the surface modification device includes; Main body 1, with a main chamber 11 in the center; The microwave stirring module 2 is located on the top of the main body 1 and extends into the cavity from the top of the main body 1. It is used to stir and microwave heat the mixed solution in the main cavity 11. The acoustic-electric coupling module 3 includes an ultrasonic component 31, an electric field generating component 32, and several reaction tubes 33. The reaction tubes 33 are distributed vertically and spaced apart on the outside of the main body 1. The bottom and top of the reaction tubes 33 are connected to the main chamber 11 through a delivery pipe 34. The ultrasonic component 31 is correspondingly arranged on the top of the reaction tubes 33 for ultrasonicating the mixed solution inside the reaction tubes 33. The electric field generating component 32 is sleeved on the reaction tubes 33. The electric field generating component 32 has multiple arc-shaped electrodes 321 distributed vertically inside it, with adjacent arc-shaped electrodes 321 having opposite polarities. That is, the surface modification device as a whole has a double-layer structure with inner and outer cavities. The microwave stirring module 2 is located in the central main chamber 11, and the acoustic-electric coupling module 3 is arranged around the main chamber 11 to avoid interference between microwaves and electric and sound fields. Meanwhile, the high-concentration particle zone formed at the bottom of the main chamber 11 due to gravity sedimentation of the mixture is preferentially pumped into the acoustic-electric coupling module 3 to undergo ultrasonic deagglomeration and electric field orientation enhancement. The modified particles, due to the enhanced surface hydrophobicity, return to the upper part of the main chamber 11 and their suspension stability is improved, and the sedimentation rate is reduced, thus forming an adaptive screening cycle: unmodified particles continue to settle and are enhanced, while modified particles float to the surface and escape from the high field strength zone, avoiding silane self-polymerization caused by excessive modification and effectively improving uniformity.
[0032] After the arc-shaped electrode 321 is installed, adjusting the current and voltage can only change the magnitude of the electric field, but cannot change the spatial distribution of the electric field, making it difficult to adapt to different working conditions. Therefore, in this embodiment, the electric field generating component 32 includes a fixed ring 322, arc-shaped electrodes 321, a sliding frame plate 323, and an adjustment mechanism 324. The fixed ring 322 includes an inner ring wall 3221 and an outer ring wall 3222, forming a mounting cavity 3223 between the inner ring wall 3221 and the outer ring wall 3222. One end of the sliding frame plate 323 is hinged to the inner ring wall 3221, and the other end of the sliding frame plate 323 is slidably connected to the outer ring wall 3222. The arc-shaped electrodes 321 are spaced apart in the mounting cavity 3223. The adjustment mechanism 324 is located at both ends of the arc-shaped electrodes 321 and is slidably connected to the side of the sliding frame plate 323 near the outer ring wall 3222. The adjustment mechanism 324 drives the sliding frame plate 323 to rotate, thereby adjusting the position of the arc-shaped electrodes 321 in the mounting cavity 3223. This configuration allows the arc-shaped electrode 321 to be radially displaced within the mounting cavity 3223, and the orientation of one side of the arc-shaped electrode 321 can be changed by the action of the adjustment mechanism 324 at different positions, thereby changing the distribution of the electric field and making the electric field generating component 32 more adaptable and adjustable.
[0033] While the position of the arc-shaped electrode 321 can be finely adjusted simply by rotating the sliding plate 323, the adjustment process causes the arc-shaped electrode 321 to be subjected to force. Therefore, in this embodiment, the adjustment mechanism 324 includes a spacer sliding wall 3241, an adjustment rod 3242, and a connecting rod 3243. The arc-shaped electrode 321 is connected to the middle of the spacer sliding wall 3241. An extension post 3244 is provided on one side of the spacer sliding wall 3241 along its length. The sliding plate 323 is correspondingly provided with a sliding groove 3245. The extension post 3244 is slidably connected to the sliding groove 3245. The adjustment rod 3242 extends from the outside of the outer ring wall 3222 into the mounting cavity 3223. The two ends of the connecting rod 3243 are respectively hinged to the side of the spacer sliding wall 3241 where the extension post 3244 is provided and the end of the adjustment rod 3242 that extends into the mounting cavity 3223. This configuration, through the spaced sliding wall 3241 that can rotate and slide relative to the sliding frame 323, significantly reduces the force on the arc-shaped electrode 321, enabling the arc-shaped electrode 321 to operate normally.
[0034] More preferably, the arc-shaped electrode 321 and the spaced sliding wall 3241 are connected by an elastic material, so that the elastic material replaces the arc-shaped electrode 321 in deformation, thereby further reducing the influence of force on the arc-shaped electrode 321.
[0035] Preferably, the spacer sliding wall 3241 is made of insulating material to prevent the spacer sliding walls 3241 from coming into contact with each other, which could cause the arc electrode 321 to short circuit.
[0036] Specifically, the arc-shaped electrode 321 is electrically connected to the outside through the top of the fixing ring 322. Those skilled in the art can set up a suitable circuit as needed, without making specific limitations.
[0037] Specifically, the ultrasonic component 31 includes an ultrasonic transducer and an amplitude transformer. The ultrasonic transducer is located at the top of the reaction tube 33, and the amplitude transformer extends downward from the center of the top of the reaction tube 33. The ultrasonic transducer inputs the generated ultrasonic waves into the reaction tube 33 through the amplitude transformer.
[0038] Preferably, each electric field generating component 32 is provided with 4, 6 or 8 arc-shaped electrodes 321.
[0039] Preferably, the main body 1 is covered with a protective shell, and a protective cavity is formed between the protective shell and the main body 1, and the acoustic-electric coupling module 3 is disposed in the protective cavity.
[0040] More preferably, the protective cavity is filled with buffer gas.
[0041] Preferably, a delivery pump is provided on the delivery pipeline 34.
[0042] In this embodiment, the adjusting rod 3242 is a screw, and one end of the adjusting rod 3242 extending into the mounting cavity 3223 is provided with a rotatable connecting sleeve 3246. The connecting rod 3243 is hinged to the connecting sleeve 3246. This arrangement allows the adjusting rod 3242 to be adjusted efficiently while ensuring the accuracy of the adjustment.
[0043] In this embodiment, the adjusting rod 3242 is simultaneously connected to two connecting rods 3243, and the spaced sliding walls 3241 connected to adjacent connecting rods 3243 are respectively connected to the edges of arc-shaped electrodes 321 of different polarities. This arrangement allows each adjusting rod 3242 to simultaneously adjust adjacent arc-shaped electrodes 321, thereby changing the electric field distribution of adjacent arc-shaped electrodes 321 and improving the adaptability of the device.
[0044] Since the acoustic-electric coupling module 3 is located on the outer edge of the main body 1, if a heat exchange jacket is used for heating outside the main body 1, it is easy to cause overheating of the part close to the acoustic-electric coupling module 3, and make the equipment bulky. Therefore, in this embodiment, the microwave stirring module 2 includes a stirring component 21, a microwave component 22, a drive motor 23, and a drive rod 24. The drive motor 23 is located on the top of the main body 1, and the drive rod 24 is connected to the output end of the drive motor 23 and extends into the main chamber 11. The microwave component 22 extends from the top of the main body 1 into the main chamber 11 and is sleeved on the outer edge of the drive rod 24. The stirring component 21 is located at the end of the drive rod 24 away from the drive motor 23 and extends upward along the outer wall of the microwave component 22.
[0045] In this embodiment, the microwave component 22 includes a microwave ring wall 221, a microwave generator 222, a spiral conduit 223, and a transmission window 224. The microwave ring wall 221 extends downward from the top of the main chamber 11. The microwave generator 222 is disposed at the top of the microwave ring wall 221. The spiral conduit 223 is embedded in the microwave ring wall 221. The transmission window 224 is disposed on the microwave ring wall 221. The spiral conduit 223 conducts the microwaves generated by the microwave generator component into the main chamber 11 through the transmission window 224. The stirring assembly 21 includes a main frame plate 211, a support plate 212, an abutment plate 213, and a connecting plate 214. The middle part of the main frame plate 211 is connected to the drive rod 24. The support plate 212 extends vertically upward from both ends of the main frame plate 211. The abutment plate 213 extends upward from the middle part of the main frame plate 211 along both sides of the outer edge of the microwave ring wall 221. The connecting plate 214 is disposed between the support plate 212 and the abutment plate 213. When the drive rod 24 drives the main frame plate 211 to rotate, the abutment plate 213 is driven to rotate around the outer surface of the microwave ring wall 221. That is, the stirring assembly 21 has an anchor-type structure. The main frame plate 2111 and the support plate 212 form a frame structure, and then the abutment plate 213 and the connecting plate 214 are set so that the stirring assembly 21 is in a plane. During rotation, the rotation rate is controlled to make the reactants fully mixed or generate laminar flow, and the mixture enters different flow states at different mixing stages.
[0046] Specifically, those skilled in the art can select a suitable microwave generator 222 and spiral conduit 223 as needed, and guide microwaves through the transmission window 224 by setting a transmitting antenna on the spiral conduit 223, without making specific limitations.
[0047] In this embodiment, in step S1, the zirconium source includes any one of zirconium oxychloride or zirconium oxynitrate; the phosphorus source includes any one of diammonium hydrogen phosphate or diammonium dihydrogen phosphate; the molar ratio of zirconium source to phosphorus source is 1:1 to 2.5; in step S2, the silane coupling agent includes γ-aminopropyltriethoxysilane, and the amount of silane coupling agent added is 12% to 20% of the mass of nano-zirconium phosphate.
[0048] The present invention also provides a silane-modified zirconium phosphate electrolyte additive prepared by any of the preparation methods described above, with a particle size of 30-80 nm.
[0049] Example 1: S1. 1 mol of zirconium oxychloride and 2 mol of diammonium hydrogen phosphate were introduced into a high-pressure synthesis reactor and stirred thoroughly. The mixture was then subjected to hydrothermal reaction at 190°C for 18 h. The reaction product was centrifuged, washed, filtered, and dried to obtain nano-zirconium phosphate. S2. Disperse 250g of nano-zirconium phosphate obtained in S1 in anhydrous ethanol, and then pass it into the main chamber 11 of the surface modification device. Add 37.5g of γ-aminopropyltriethoxysilane to the main chamber 11, and let the mixed solution be initially mixed at 70°C for 0.5h under the action of microwave stirring module 2 in the main chamber 11. S3. After initial mixing, the microwave stirring module 2 continues to operate, while the mixed solution at the bottom of the main chamber 11 flows from bottom to top through the acoustic-electric coupling module 3 and then flows back into the main chamber 11 from the top. The mixed solution is modified for 3 hours in the acoustic-electric coupling module 3 under the combined action of electric field and ultrasound; the field strength is 50 V / cm; the ultrasound frequency is 30kHz; and the power density is 300 W / L.
[0050] S4. After modification, the mixed solution obtained in S3 is centrifuged and dried to obtain silane-modified zirconium phosphate electrolyte additive.
[0051] Comparative Example 1 Blank comparison.
[0052] 1 wt% of the silane-modified zirconium phosphate electrolyte additive obtained in Example 1 was added to a 1 M LiPF6 / EC+DMC+EMC (1:1:1) electrolyte and ultrasonically dispersed for 30 minutes. The electrolytes of Example 1 and Comparative Example 1 were subjected to high-temperature storage tests (60°C, 7 days) and capacity tests (1000 cycles at 1C). The test results are as follows: High-temperature storage capacity loss: Example 1: 2.8%; Comparative Example: 6.5%; Capacity retention rate: 86.3% in Example 1; 78.1% in the comparative example.
[0053] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.
[0054] Although this document uses terms such as XX, XX, etc. extensively, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the essence of the invention; interpreting them as any kind of additional limitation would contradict the spirit of the invention. The terms "first," "second," etc. (if present) in the specification and claims of the embodiments of the invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.
[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing a silane-modified zirconium phosphate electrolyte additive, characterized in that, The steps are as follows: S1. The zirconium source and phosphorus source are introduced into a high-pressure synthesis reactor, stirred and mixed thoroughly, and hydrothermally reacted at 160℃~200℃ for 12~24h. The reaction product is centrifuged, washed, filtered and dried to obtain nano-zirconium phosphate. S2. The nano-zirconium phosphate obtained in S1 is dispersed in anhydrous ethanol and then introduced into the main chamber (11) of the surface modification device. A silane coupling agent is added to the main chamber (11) so that the mixed solution is initially mixed at 60°C to 80°C under the action of the microwave stirring module (2) in the main chamber (11). S3. After initial mixing, the microwave stirring module (2) continues to operate, while the mixed solution at the bottom of the main chamber (11) flows from bottom to top through the acoustic-electric coupling module (3) and then flows back to the main chamber (11) from the top. The mixed solution is modified in the acoustic-electric coupling module (3) under the combined action of electric field and ultrasound. S4. After modification, the mixed solution obtained in S3 is centrifuged and dried to obtain silane-modified zirconium phosphate electrolyte additive.
2. The preparation method according to claim 1, characterized in that: The surface modification device includes: The main body (1) has the main chamber (11) at its center; The microwave stirring module (2) is disposed on the top of the main body (1) and extends into the cavity from the top of the main body (1) for stirring and microwave heating the mixed solution in the main cavity (11); The acoustic-electric coupling module (3) includes an ultrasonic component (31), an electric field generating component (32), and several reaction tubes (33). The reaction tubes (33) are distributed vertically and spaced apart on the outside of the main body (1). The bottom and top of the reaction tubes (33) are connected to the main chamber (11) through a delivery pipe (34). The ultrasonic component (31) is correspondingly disposed on the top of the reaction tube (33) for ultrasonic treatment of the mixed solution in the reaction tube (33). The electric field generating component (32) is sleeved on the reaction tube (33). The electric field generating component (32) has arc-shaped electrodes (321) distributed vertically inside it. There are multiple arc-shaped electrodes (321), and the polarities of adjacent arc-shaped electrodes (321) are opposite.
3. The preparation method according to claim 2, characterized in that: The electric field generating assembly (32) includes a fixed ring (322), the arc-shaped electrode (321), a sliding frame (323), and an adjustment mechanism (324). The fixed ring (322) includes an inner ring wall (3221) and an outer ring wall (3222), forming an installation cavity (3223) between the inner ring wall (3221) and the outer ring wall (3222). One end of the sliding frame (323) is hinged to the inner ring wall (3221), and the other end of the sliding frame (323) is hinged to the inner ring wall (3221). One end is slidably connected to the outer ring wall (3222); the arc-shaped electrodes (321) are spaced apart in the mounting cavity (3223); the adjustment mechanism (324) is disposed at both ends of the arc-shaped electrodes (321) and slidably connected to the side of the sliding frame plate (323) near the outer ring wall (3222); the adjustment mechanism (324) drives the sliding frame plate (323) to rotate, thereby adjusting the position of the arc-shaped electrodes (321) in the mounting cavity (3223).
4. The preparation method according to claim 3, characterized in that: The adjustment mechanism (324) includes a sliding wall (3241), an adjustment rod (3242), and a connecting rod (3243); the arc-shaped electrode (321) is connected to the middle of the sliding wall (3241), an extension column (3244) is provided on one side of the sliding wall (3241) in the length direction, and a corresponding groove (3245) is provided on the sliding frame plate (323), and the extension column (3244) is slidably connected to the groove (3245); the adjustment rod (3242) extends from the outside of the outer ring wall (3222) into the mounting cavity (3223), and the two ends of the connecting rod (3243) are respectively hinged to the side of the sliding wall (3241) where the extension column (3244) is provided and the end of the adjustment rod (3242) extending into the mounting cavity (3223).
5. The preparation method according to claim 4, characterized in that: The adjusting rod (3242) is a screw rod. One end of the adjusting rod (3242) extending into the mounting cavity (3223) is provided with a rotatable connecting sleeve (3246). The connecting rod (3243) is hinged to the connecting sleeve (3246).
6. The preparation method according to claim 4, characterized in that: The adjusting rod (3242) is connected to two connecting rods (3243) at the same time, and the spaced sliding wall (3241) connected to the adjacent connecting rods (3243) is connected to the edge of the arc-shaped electrode (321) of different polarities respectively.
7. The preparation method according to claim 2, characterized in that: The microwave stirring module (2) includes a stirring assembly (21), a microwave assembly (22), a drive motor (23), and a drive rod (24). The drive motor (23) is located on the top of the main body (1). The drive rod (24) is connected to the output end of the drive motor (23) and extends into the main chamber (11). The microwave assembly (22) extends from the top of the main body (1) into the main chamber (11) and is fitted onto the outer edge of the drive rod (24). The stirring assembly (21) is located at the end of the drive rod (24) away from the drive motor (23) and extends upward along the outer wall of the microwave assembly (22).
8. The preparation method according to claim 7, characterized in that: The microwave assembly (22) includes a microwave ring wall (221), a microwave generator (222), a spiral conduit (223), and a transmission window (224). The microwave ring wall (221) extends downward from the top of the main chamber (11). The microwave generator (222) is located at the top of the microwave ring wall (221). The spiral conduit (223) is embedded in the microwave ring wall (221). The transmission window (224) is located on the microwave ring wall (221). The spiral conduit (223) conducts the microwaves generated by the microwave generator assembly into the main chamber (11) through the transmission window (224). The stirring assembly (21) includes a main frame plate (211), a support plate (212), an abutment plate (213), and a connecting plate (214). The middle part of the main frame plate (211) is connected to the drive rod (24). The support plate (212) extends vertically upward from both ends of the main frame plate (211). The abutment plate (213) extends upward from the middle part of the main frame plate (211) along both sides of the outer edge of the microwave ring wall (221). The connecting plate (214) is disposed between the support plate (212) and the abutment plate (213). When the drive rod (24) drives the main frame plate (211) to rotate, the abutment plate (213) is driven to rotate around the outer surface of the microwave ring wall (221).
9. The preparation method according to claim 1, characterized in that: In step S1, the zirconium source includes any one of zirconium oxychloride or zirconium oxynitrate; the phosphorus source includes any one of diammonium hydrogen phosphate or ammonium dihydrogen phosphate; the molar ratio of the zirconium source to the phosphorus source is 1:1 to 2.5; in step S2, the silane coupling agent includes γ-aminopropyltriethoxysilane, and the amount of the silane coupling agent added is 12% to 20% of the mass of the nano-zirconium phosphate.
10. A silane-modified zirconium phosphate electrolyte additive prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The particle size is 30–80 nm.