A hydroxyapatite fiber composite solid electrolyte, its preparation method and application

Abstract

This application provides a hydroxyapatite fiber composite solid electrolyte, including Sn 2+ and I ‑ Co-doped porous hydroxyapatite fibers and oxide conductive particles loaded on the porous hydroxyapatite fibers. Porous hydroxyapatite fibers are obtained by electrospinning, utilizing Sn... 2+ Ca in partially substituted hydroxyapatite 2+ I ‑ Sn was obtained by partially substituting the hydroxyl groups in hydroxyapatite. 2+ and I ‑ Co-doped porous hydroxyapatite fibers. This hydroxyapatite fiber composite solid electrolyte exhibits excellent ionic conductivity. Using this hydroxyapatite fiber composite solid electrolyte in the preparation of lithium-ion batteries can reduce the interfacial impedance between the positive and negative electrodes and the electrolyte, improve its charge-discharge performance, and result in lithium-ion batteries with good cycle stability and safety.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery materials, specifically relating to a composite solid electrolyte, its preparation method, and its application. Background Technology

[0002] With the reform of the energy industry and the advancement of people's lifestyles, the huge demand in the consumer market for new energy vehicles, mobile electronic devices, and smart wearable devices has promoted continuous research and innovation in the lithium battery industry. The market applications of lithium batteries are mainly distributed in consumer electronics and power battery markets, and demand in these areas continues to grow. Traditional liquid lithium-ion batteries exhibit good electrochemical performance, with highly conductive organic electrolytes exhibiting excellent wettability with electrode surfaces. However, in practical applications, liquid lithium-ion batteries still face some unresolved problems, such as poor safety, high electrolyte fluidity and a relatively low energy density limit. Furthermore, the organic solvents in the electrolyte pose flammability, explosiveness, and decomposition risks, and electrolyte leaks can cause environmental pollution and safety issues.

[0003] Compared to traditional liquid lithium-ion batteries, lithium batteries using solid-state electrolytes have become a research hotspot in the energy storage field. The inherent flame retardancy of solid-state electrolytes contributes to their high safety, while their solid-state nature allows for operation over a wide temperature range and is relatively environmentally friendly. Replacing traditional electrolytes with solid-state electrolytes is one of the most effective ways to solve the safety and performance problems of lithium batteries, and it is of great significance for advancing the development of high-energy-density lithium batteries.

[0004] All-solid-state lithium-ion batteries mainly consist of a solid electrolyte, a lithium metal anode, and a positive electrode active material. Lithium metal has a high theoretical specific capacity and the lowest electrochemical potential, which can greatly improve the volumetric energy density of the battery and achieve high-efficiency battery use.

[0005] Compared to liquid electrolytes, solid-state electrolytes exhibit superior thermal and electrochemical stability, significantly enhancing battery safety and performance stability. Solid-state electrolytes can be categorized into inorganic solid-state electrolytes and polymer solid-state electrolytes, with inorganic solid-state electrolytes further including oxide solid-state electrolytes and sulfide solid-state electrolytes. Polymer solid-state electrolytes possess excellent mechanical properties, enabling good interfacial contact with both positive and negative electrodes, and exhibit good compatibility with lithium metal anodes; however, their low room-temperature ionic conductivity limits their application in all-solid-state batteries. Sulfide solid-state electrolytes possess relatively high ionic conductivity and excellent thermal stability at room temperature, but their poor chemical stability leads to the release of toxic H2S gas upon exposure to air, necessitating stringent experimental conditions and high production costs. Oxide solid-state electrolytes can achieve high Li-to-Li ratios. +Li exhibits good conductivity, electrochemical stability, and thermal stability, making it promising for industrial applications. However, its high rigidity and relatively poor mechanical properties result in poor interfacial contact with the positive and negative electrodes in all-solid-state batteries, leading to significant interfacial impedance limitations between the positive and negative electrodes and the electrolyte. + The conduction in the middle, along with the point contact between the lithium metal anode and the lithium dendrite, leads to the nucleation and growth of lithium dendrites, resulting in uneven lithium deposition at the interface and further causing unstable battery cycling.

[0006] To address the issues of high interfacial impedance between oxide solid electrolytes and positive and negative electrodes, as well as lithium dendrites on the negative electrode, some studies have proposed introducing a buffer layer at the interface to improve interfacial contact conditions and reduce interfacial impedance. These methods can improve the interfacial compatibility and stability between the electrolyte and the Li negative electrode to some extent. However, these methods do not fundamentally solve the problem of poor mechanical properties of oxide solid electrolytes, and they are not effective in improving the ionic conductivity of the electrolyte itself.

[0007] Therefore, solid electrolytes with high ionic conductivity, good interfacial contact, and excellent safety and cycling stability have become the main research targets. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a hydroxyapatite fiber composite solid electrolyte with high ionic conductivity, good interfacial contact, excellent safety and cycle stability, which can be used to prepare lithium-ion batteries.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows:

[0010] This application provides a hydroxyapatite fiber composite solid electrolyte, comprising: Sn 2+ and I - Co-doped porous hydroxyapatite fibers and oxide conductive particles supported on the porous hydroxyapatite fibers; the oxide conductive particles are selected from NASICON-type solid electrolytes, garnet-type solid electrolytes, perovskite-type solid electrolytes, and LiAl(PO4)(OH)2. 1-z F z ), where 0≤z≤1 or one or more of them.

[0011] Preferably, the Sn 2+ The molar ratio of I to hydroxyapatite is 0.1–0.3:1. - The molar ratio of hydroxyapatite to hydroxyapatite is 0.2–0.6:1.

[0012] Preferably, the porous hydroxyapatite fiber has a diameter of 50–400 nm and a length of 30–150 μm.

[0013] In some embodiments, the NASICON-type solid electrolyte is selected from Li 1+x Al x Ti 2-x (PO4)3, where 0 ≤ x ≤ 2; or Li 1+y Al y Ge 2-y (PO4)3, where 0 ≤ y ≤ 1 or one or more of these;

[0014] The garnet-type solid electrolyte is selected from Li 7-m La3Zr 2-m Ta m O 12 where 0 ≤ m ≤ 2;

[0015] The perovskite-type solid electrolyte is selected from Li 3a La 2 / 3-a TiO3, where 0 < a ≤ 0.16.

[0016] Preferably, the NASICON-type solid electrolyte is selected from Li 1.4 Al 0.4 Ti 1.6 (PO4)3 or Li 1.5 Al 0.5 Ge 1.5 (PO4)3; the LiAl(PO4)(OH) 1-z F z This can also be represented as LiAl(OH) 1-z F z (PO4), or can be represented as LiAlPO4(OH) 1-z ,F z It can also be represented as LiAlPO4(OH) 1-z ·F z The LiAl(PO4)(OH) 1-z F z Selected from LiAl(PO4)(OH) 0.4 F 0.6 ) or LiAl(PO4)(OH 0.7 F 0.3 The garnet-type solid electrolyte is selected from Li7La3Zr2O. 12 The perovskite-type solid electrolyte is selected from Li. 0.33 La 0.557 TiO3.

[0017] Preferably, the Sn 2+ I - The mass ratio of doped hydroxyapatite fibers to oxide conductive particles is 1:0.8 to 1.8.

[0018] Preferably, the hydroxyapatite fiber composite solid electrolyte further includes a lithium salt.

[0019] In some embodiments, the lithium salt is selected from one or more of LiTFSI, LiFSI, LiCF3SO3, LiPF6, LiAsF6, LiClO4, LiDFOB, and LiBOB.

[0020] Preferably, the lithium salt and Sn 2+ I - The mass ratio of the doped porous hydroxyapatite fibers is 1:1.5 to 7.6.

[0021] This application provides a hydroxyapatite, wherein the hydroxyapatite is Sn. 2+ and I - Co-doped porous hydroxyapatite fibers.

[0022] In the hydroxyapatite described above, the Sn 2+ The molar ratio of I to hydroxyapatite is 0.1–0.3:1. - The molar ratio of hydroxyapatite to hydroxyapatite is 0.2–0.6:1.

[0023] In the hydroxyapatite, the porous hydroxyapatite fibers have a diameter of 50–400 nm and a length of 30–150 μm.

[0024] This application also provides a method for preparing hydroxyapatite, comprising the following steps:

[0025] (a) A calcium source, a phosphorus source and a pore-forming agent are mixed and reacted, and the resulting reaction solution is spun to obtain a porous hydroxyapatite fiber precursor.

[0026] (b) The hydroxyapatite fiber precursor, Sn source, and I source were mixed and subjected to low-temperature heat treatment and high-temperature heat treatment in sequence to obtain Sn. 2+ I - Co-doped porous hydroxyapatite fibers.

[0027] This application provides a method for preparing a hydroxyapatite fiber composite solid electrolyte, comprising the following steps:

[0028] (a) Sn 2+ and I - A suspension was obtained by mixing co-doped porous hydroxyapatite fibers, lithium salts, and oxide conductive particles.

[0029] (b) The suspension is cast, dried and hot-pressed to obtain hydroxyapatite fiber composite solid electrolyte.

[0030] This application provides a lithium-ion battery, including the aforementioned hydroxyapatite fiber composite solid electrolyte.

[0031] This application provides a hydroxyapatite fiber composite solid electrolyte, including Sn 2+ and I - Co-doped porous hydroxyapatite fibers and oxide conductive particles supported on the porous hydroxyapatite fibers, wherein the oxide conductive particles are selected from NASICON-type solid electrolytes, garnet-type solid electrolytes, perovskite-type solid electrolytes, and LiAl(PO4)(OH)2. 1-z F z ), where 0≤z≤1 or one or more of the following. Porous hydroxyapatite fibers are obtained by electrospinning, using Sn 2+ Ca in partially substituted hydroxyapatite 2+ I - Sn was obtained by partially substituting the hydroxyl groups in hydroxyapatite. 2+ and I - Co-doped porous hydroxyapatite fibers. This composite solid electrolyte exhibits excellent ionic conductivity. Using this composite solid electrolyte in lithium-ion batteries can reduce the interfacial impedance between the positive and negative electrodes and the electrolyte, improving its charge-discharge performance. The lithium-ion batteries then demonstrate good cycle stability and safety. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments thereof. 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.

[0033] This invention provides a hydroxyapatite fiber composite solid electrolyte, comprising Sn 2+ and I - Co-doped porous hydroxyapatite fibers and oxide conductive particles loaded on the porous hydroxyapatite fibers.

[0034] In some specific implementations, the Sn 2+ and I - In co-doped porous hydroxyapatite fibers, Sn 2+ Ca in porous hydroxyapatite fibers is partially replaced 2+ I - The Sn partially replaces the hydroxyl groups in porous hydroxyapatite fibers. 2+ The molar ratio of I to hydroxyapatite is 0.1–0.3:1, preferably 0.20:1. -The molar ratio of the porous hydroxyapatite to hydroxyapatite is 0.2–0.6:1, preferably 0.40:1. The diameter of the porous hydroxyapatite fiber is 50–400 nm, preferably 50 nm, 100 nm, 200 nm, 300 nm, or 400 nm; the length of the porous hydroxyapatite fiber is 30–150 μm, preferably 30 μm, 70 μm, 100 μm, 120 μm, or 150 μm. In some embodiments, the oxide conductive particles are selected from NASICON-type solid electrolytes, garnet-type solid electrolytes, perovskite-type solid electrolytes, and LiAl(PO4)(OH)2. 1-z F z ), wherein 0≤z≤1 or one or more of these, and the NASICON type solid electrolyte is preferably Li 1+x Al x Ti 2-x (PO4)3, where 0 ≤ x ≤ 2; and Li 1+ y Al y Ge 2-y (PO4)3, where 0 ≤ y ≤ 1 or one or more of these, for example, could be Li 1.4 Al 0.4 Ti 1.6 (PO4)3 or Li 1.5 Al 0.5 Ge 1.5 (PO4)3. LiAl(PO4)(OH 1-z F z ), preferably LiAl(PO4)(OH 0.4 F 0.6 ) or LiAl(PO4)(OH 0.7 F 0.3 Garnet-type solid electrolytes are preferably Li. 7-m La3Zr 2-m Ta m O 12 Where 0≤m≤2, for example, it can be Li7La3Zr2O 12 The preferred perovskite-type solid electrolyte is Li. 3a La 2 / 3-a TiO3, where 0 < a ≤ 0.16, can be, for example, Li. 0.33 La 0.557 TiO3. The Sn 2+ I - The mass ratio of doped porous hydroxyapatite fibers to oxide conductive particles is 1:0.8–1.8, preferably 1:0.8, 1:1, 1:1.128, 1:1.19, 1:1.5, 1:1.657, or 1:1.8. The oxide conductive particles are loaded onto Sn... 2+ I- The doped porous hydroxyapatite fibers are placed in or on the surface of the fibers, preferably loaded with Sn. 2+ I - In the pores of the doped porous hydroxyapatite fibers.

[0035] In some embodiments, the hydroxyapatite fiber composite solid electrolyte further includes a lithium salt, preferably a lithium salt, more preferably one or more of LiTFSI, LiFSI, LiCF3SO3, LiPF6, LiAsF6, LiClO4, LiDFOB, and LiBOB, for example, LiTFSI, LiFSI, LiCF3SO3, LiPF6, LiAsF6, LiClO4, LiDFOB, or LiBOB. The lithium salt reacts with Sn... 2+ I - The mass ratio of the doped porous hydroxyapatite fibers is preferably 1:1.5 to 7.6, more preferably 1:1.5, 1:2.667, 1:3, 1:4.7, 1:5, 1:5.25 or 1:7.6.

[0036] This invention provides a Sn 2+ I - A method for preparing doped porous hydroxyapatite fibers includes the following steps:

[0037] A calcium source, a phosphorus source, and a pore-forming agent are mixed and reacted. The resulting reaction solution is then spun to obtain a porous hydroxyapatite fiber precursor.

[0038] Specifically, a calcium source and a phosphorus source are mixed in a solvent. In some possible implementations, the calcium source is a calcium salt, preferably calcium nitrate, calcium oxide, calcium hydroxide, or calcium hydrogen phosphate, more preferably calcium nitrate tetrahydrate. In some possible implementations, the phosphorus source is an ester compound of phosphoric acid, preferably triethyl phosphate. The ratio of calcium source to phosphorus source is 10–16 g: 4–8 mL, preferably 13.2 g: 5.7 mL. The solvent is preferably an aqueous solution of alcohol, more preferably an aqueous solution of ethanol, with a volume concentration of 80%–90%, preferably 83.33%. The volume ratio of phosphorus source to solvent is 1:5.5–6.5, preferably 1:6.32. The mixing is carried out under stirring for 100–400 min, preferably 120–360 min, more preferably 100 min, 120 min, 240 min or 400 min. After mixing, a pore-forming agent is added, preferably PVP. The mass ratio of the calcium source to the pore-forming agent is 1:0.45–0.91, preferably 1:0.49, 1:0.53, 1:0.606, 1:0.757 or 1:0.91. After adding the pore-forming agent, the mixture is stirred for 120–300 min, preferably 120 min, 240 min or 300 min. In some embodiments, the stirring is carried out at room temperature. After stirring, a clear and transparent reaction solution is obtained. The reaction solution is transferred to a syringe with a volume of 10–30 mL, preferably 10 mL, 20 mL, or 30 mL, for spinning. Spinning is preferably performed under positive high voltage (10.0–13.0 kV) and negative voltage (-4.5–-1.5 kV). The positive high voltage can be 10.0 kV, 10.5 kV, 11.5 kV, 12.5 kV, or 13.0 kV, and the negative voltage can be -4.5 kV, -3.0 kV, -2.5 kV, or -1.5 kV. After spinning, a porous hydroxyapatite fiber precursor is obtained on a collecting plate.

[0039] Porous hydroxyapatite fiber precursor, Sn source, and I source were mixed and subjected to low-temperature heat treatment and high-temperature heat treatment sequentially to obtain Sn. 2+ I - The porous hydroxyapatite fiber is co-doped, wherein the diameter of the porous hydroxyapatite fiber is 50-400 nm, preferably 50 nm, 100 nm, 200 nm, 300 nm or 400 nm; and the length is 30-150 μm, preferably 30 μm, 70 μm, 100 μm, 120 μm or 150 μm.

[0040] Specifically, a porous hydroxyapatite fiber precursor, a Sn source, and an I source are mixed in a solvent. The Sn source and I source are preferably compounds of Sn and I, more preferably SnI2. The solvent is preferably an alcohol or deionized water, more preferably anhydrous ethanol or deionized water. The mass ratio of the porous hydroxyapatite fiber precursor to SnI2 is 5:0.10 to 0.30, preferably 5:0.10, 5:0.15, 5:0.2, 5:0.25, or 5:0.3. The amount of the porous hydroxyapatite fiber precursor to the solvent is 1g:4 to 6mL, preferably 1g:4mL, 1g:5mL, or 1g:6mL. The mixing is carried out under stirring for 120 to 360 min, preferably 120 min, 240 min, or 360 min. After mixing, a precursor mixture is obtained. The precursor mixture is then subjected to low-temperature heat treatment, preferably drying in a drying oven. The drying oven temperature is preferably 70–200°C, for example, 70°C, 80°C, 100°C, 125°C, 150°C, or 200°C. The drying time is preferably 6–48 hours, for example, 6 hours, 15 hours, 18 hours, 24 hours, 30 hours, or 48 hours. After drying, a high-temperature heat treatment is performed, preferably in a muffle furnace. The heating rate of the muffle furnace is preferably 4–6°C / min, for example, 4°C / min, 5°C / min, or 6°C / min. The muffle furnace temperature is raised to 500–850°C, preferably 500°C, 550°C, 600°C, 700°C, 750°C, 800°C, or 850°C. The heat treatment time is preferably 8–18 hours, for example, 8 hours, 10 hours, 16 hours, or 18 hours. After heat treatment, Sn is obtained. 2+ I - Co-doped porous hydroxyapatite fibers.

[0041] This invention provides a method for preparing a hydroxyapatite fiber composite solid electrolyte, comprising the following steps:

[0042] Sn 2+ and I - Co-doped porous hydroxyapatite fibers were ground and sieved, Sn 2+ I - The preparation method of co-doped porous hydroxyapatite fibers is as described above. The sieve mesh size is 100-300 mesh, preferably 100 mesh, 200 mesh, or 300 mesh. Sn passing through the sieve is then... 2+ I - Co-doped porous hydroxyapatite fibers are mixed with solvent, Sn 2+ I -The ratio of co-doped porous hydroxyapatite fiber to solvent is 3-5 g: 40-50 mL, preferably 3.8 g: 40 mL, 4.0 g: 50 mL, 3.0 g: 50 mL, 4.2 g: 50 mL, 3.5 g: 50 mL, or 4.7 g: 50 mL. The solvent is preferably one or more of N-methylpyrrolidone (NMP), ethylene carbonate, propylene carbonate, butenyl carbonate, dimethyl carbonate, ethylene carbonate, methyl ethyl carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, and acetonitrile, more preferably NMP, ethylene carbonate, ethylene carbonate, propylene carbonate, or dimethyl carbonate. The mixing is preferably carried out under stirring for 30-180 min, preferably 30 min, 45 min, 50 min, 100 min, 150 min, or 180 min. After mixing, a lithium salt is added. The lithium salt is preferably a lithium salt, more preferably one or more of LiTFSI, LiFSI, LiCF3SO3, LiPF6, LiAsF6, LiClO4, LiDFOB, and LiBOB. For example, it can be LiTFSI, LiFSI, LiCF3SO3, LiPF6, LiAsF6, LiClO4, LiDFOB, or LiBOB. The lithium salt reacts with Sn. 2+ I - The mass ratio of the doped porous hydroxyapatite fibers is 1:1.5 to 7.6, preferably 1:1.5, 1:2.667, 1:3, 1:4.7, 1:5, 1:5.25 or 1:7.6. After adding lithium salt, the mixture is stirred for 45 to 180 min, preferably 45 min, 50 min, 90 min, 100 min or 180 min.

[0043] After stirring, oxide conductive particles are added. These oxide conductive particles are preferably selected from NASICON-type solid electrolytes, garnet-type solid electrolytes, perovskite-type solid electrolytes, and LiAl(PO4)(OH)2. 1-z F z ), wherein 0≤z≤1 or one or more of the following. The NASICON-type solid electrolyte is preferably Li. 1+x Al x Ti 2-x (PO4)3, where 0 ≤ x ≤ 2; and Li 1+ y Al y Ge 2-y (PO4)3, where 0 ≤ y ≤ 1 or one or more of these, for example, could be Li 1.4 Al 0.4 Ti 1.6 (PO4)3 or Li 1.5 Al 0.5 Ge 1.5(PO4)3. LiAl(PO4)(OH 1-z F z ), preferably LiAl(PO4)(OH 0.4 F 0.6 ) or LiAl(PO4)(OH 0.7 F 0.3 Garnet-type solid electrolytes are preferably Li. 7-m La3Zr 2-m Ta m O 12 Where 0≤m≤2, for example, it can be Li7La3Zr2O 12 The preferred perovskite-type solid electrolyte is Li. 3a La 2 / 3-a TiO3, where 0 < a ≤ 0.16, can be, for example, Li. 0.33 La 0.557 TiO3. The Sn 2+ I - The mass ratio of the doped porous hydroxyapatite fiber to the oxide conductive particles is 1:0.8 to 1.8, preferably 1:0.8, 1:1, 1:1.128, 1:1.19, 1:1.5, 1:1.657 or 1:1.8. After adding the oxide conductive particles, the mixture is stirred for 3 to 20 hours, preferably 3 hours, 6 hours, 8 hours, 15 hours or 20 hours.

[0044] After stirring, a suspension is obtained. The suspension is then cast and dried. The drying is preferably carried out in a vacuum drying oven. The temperature of the vacuum drying oven is 70-160℃, preferably 70℃, 80℃, 110℃, 120℃ or 160℃, and the drying time is 3-24h, preferably 3h, 6h, 18h or 24h. After drying, hot pressing is performed at a temperature of 60–180°C, preferably 60°C, 75°C, 90°C, 100°C, 150°C, 160°C, or 180°C, for a time of 20–240 min, preferably 20 min, 30 min, 60 min, 80 min, 120 min, 200 min, or 240 min. After hot pressing, a composite solid electrolyte is obtained with a thickness of 40–100 μm, preferably 40 μm, 50 μm, 60 μm, 70 μm, 75 μm, 80 μm, or 100 μm.

[0045] In the hydroxyapatite fiber composite solid electrolyte provided by this invention, the Ca in hydroxyapatite... 2+ Sn at position doping 2+This increases the crystal structure of hydroxyapatite, coarsening its fibrous shape to provide more pores and acid-base sites, increasing the contact area with oxide conductive particles and lithium salts, and promoting lithium-ion conduction at the interface between hydroxyapatite and oxide conductive particles; simultaneously, Sn doping in hydroxyapatite... 2+ and I - Li that can be generated in situ with lithium metal anode x Sn and LiI can greatly improve the interfacial contact between solid electrolytes and Li. x Sn alloys for Li + Lowering the migration barrier has a good effect and can uniformly make the interface electric field and Li + Flux homogenization, thereby promoting Li + Uniform deposition suppresses Li dendrite growth, reduces interfacial impedance, and ensures battery cycle stability. Furthermore, LiI acts as an electronic insulator, making Li... + This invention provides a hydroxyapatite fiber composite solid electrolyte, comprising Sn, which enables efficient power transmission and thus achieves efficient charging and discharging of the battery. 2+ and I - Co-doped porous hydroxyapatite fibers and oxide conductive particles loaded on the porous hydroxyapatite fibers. Porous hydroxyapatite fibers are obtained by electrospinning, utilizing Sn... 2+ Ca in partially substituted hydroxyapatite 2+ I - Sn was obtained by partially substituting the hydroxyl groups in hydroxyapatite. 2+ and I - Co-doped porous hydroxyapatite fibers. This hydroxyapatite fiber composite solid electrolyte exhibits excellent ionic conductivity. Using this hydroxyapatite fiber composite solid electrolyte in the preparation of lithium-ion batteries can reduce the interfacial impedance between the positive and negative electrodes and the electrolyte, improve its charge-discharge performance, and result in lithium-ion batteries with good cycle stability and safety.

[0046] Example 1

[0047] 30 mL of anhydrous ethanol and 6 mL of deionized water were mixed, and 13.20 g of calcium nitrate tetrahydrate and 5.7 mL of triethyl phosphate were added. The mixture was stirred for 240 min until homogeneous. Then, 6 g of PVP was added, and the mixture was stirred at room temperature for 240 min to obtain a clear and transparent electrospinning solution. The electrospinning solution was transferred to a 20 mL syringe, and spinning was performed under a positive voltage of 11.5 kV and a voltage of -2.5 kV. Hydroxyapatite fiber precursors were obtained on a collection plate. 5 g of the precursor was added to 20 mL of anhydrous ethanol solvent, and 0.10 g of SnI2 was added. The mixture was stirred for 120 min to obtain a precursor mixture. The precursor mixture was dried in a drying oven at 100 °C for 24 h. After drying, the mixture was transferred to a muffle furnace, and the temperature of the muffle furnace was increased to 500 °C at a rate of 6 °C / min. The mixture was heat-treated at 500 °C for 18 h to obtain Sn. 2+ I - Co-doped porous hydroxyapatite fibers with a diameter of 50 nm and a length of 30 μm.

[0048] The Sn obtained above 2+ I - Co-doped porous hydroxyapatite fibers were ground and then passed through a 200-mesh sieve. 3.8 g of the sieved Sn was then collected. 2+ I - Co-doped porous hydroxyapatite fibers were added to 40 mL of NMP solvent and stirred for 45 min. Then, 0.5 g of LiPF6 was added and stirred for another 45 min. Finally, 5.7 g of Li... 1.4 Al 0.4 Ti 1.6 (PO4)3 was stirred for 6 hours to obtain a suspension. The suspension was then cast and dried in a vacuum drying oven at 80°C for 6 hours. Finally, it was hot-pressed at 75°C for 60 minutes to obtain a hydroxyapatite fiber composite solid electrolyte with a thickness of 50 μm.

[0049] Example 2

[0050] 30 mL of anhydrous ethanol and 6 mL of deionized water were mixed, and 13.20 g of calcium nitrate tetrahydrate and 5.7 mL of triethyl phosphate were added. The mixture was stirred for 400 min until homogeneous. Then, 8 g of PVP was added, and the mixture was stirred at room temperature for 120 min to obtain a clear and transparent electrospinning solution. The electrospinning solution was transferred to a 30 mL syringe, and spinning was performed under a positive voltage of 12.5 kV and a voltage of -3.0 kV. Hydroxyapatite fiber precursors were obtained on a collection plate. 5 g of the precursor was added to 30 mL of anhydrous ethanol solvent, and 0.20 g of SnI2 was added. The mixture was stirred for 240 min to obtain a precursor mixture. The precursor mixture was dried in a drying oven at 150 °C for 18 h. After drying, the mixture was transferred to a muffle furnace, and the temperature of the muffle furnace was increased to 550 °C at a rate of 5 °C / min. The mixture was then heat-treated at 500 °C for 16 h to obtain Sn. 2+ I - Co-doped porous hydroxyapatite fibers with a diameter of 100 nm and a length of 70 μm.

[0051] The Sn obtained above 2+ I - Co-doped porous hydroxyapatite fibers were ground and then passed through a 100-mesh sieve. 4.0 g of the sieved Sn was then collected. 2+ I - Co-doped porous hydroxyapatite fibers were added to 50 mL of ethylene carbonate solvent and stirred for 180 min. Then, 1.5 g of LiTFSI was added and stirred for 30 min. Finally, 7.2 g of LiAl(PO4)(OH)2 was added. 0.4 F 0.6 Stirring for 8 hours yields a suspension. The suspension is then cast and dried in a vacuum drying oven at 70°C for 24 hours. Finally, it is hot-pressed at 60°C for 240 minutes to obtain a hydroxyapatite fiber composite solid electrolyte with a thickness of 100 μm.

[0052] Example 3

[0053] 30 mL of anhydrous ethanol and 6 mL of deionized water were mixed, and 13.20 g of calcium nitrate tetrahydrate and 5.7 mL of triethyl phosphate were added. The mixture was stirred for 100 min until homogeneous. Then, 10 g of PVP was added, and the mixture was stirred at room temperature for 300 min to obtain a clear and transparent electrospinning solution. The electrospinning solution was transferred to a 20 mL syringe, and spinning was performed under a positive voltage of 13.0 kV and a voltage of -4.5 kV. Hydroxyapatite fiber precursors were obtained on a collection plate. 5 g of the precursor was added to 20 mL of deionized water solvent, and 0.25 g of SnI2 was added. The mixture was stirred for 360 min to obtain a precursor mixture. The precursor mixture was dried in a drying oven at 70 °C for 48 h. After drying, the mixture was transferred to a muffle furnace, and the temperature of the muffle furnace was increased to 600 °C at a rate of 4 °C / min. The mixture was heat-treated at 600 °C for 10 h to obtain Sn. 2+ I - Co-doped porous hydroxyapatite fibers with a diameter of 200 nm and a length of 100 μm.

[0054] The Sn obtained above 2+ I - Co-doped porous hydroxyapatite fibers were ground and then passed through a 300-mesh sieve. 3.0 g of the sieved Sn was then collected. 2+ I - Co-doped porous hydroxyapatite fibers were added to 50 mL of ethylene carbonate solvent and stirred for 30 min. Then, 2.0 g of LiFSI was added and stirred for 180 min. Finally, 2.4 g of LiAl(PO4)(OH)2 was added. 0.7 F 0.3 Stirring for 3 hours yields a suspension. The suspension is then cast and dried in a vacuum drying oven at 160°C for 3 hours. Finally, it is hot-pressed at 180°C for 20 minutes to obtain a hydroxyapatite fiber composite solid electrolyte with a thickness of 40 μm.

[0055] Example 4

[0056] 30 mL of anhydrous ethanol and 6 mL of deionized water were mixed, and 13.20 g of calcium nitrate tetrahydrate and 5.7 mL of triethyl phosphate were added. The mixture was stirred for 240 min until homogeneous. Then, 12 g of PVP was added, and the mixture was stirred at room temperature for 300 min to obtain a clear and transparent electrospinning solution. The electrospinning solution was transferred to a 10 mL syringe, and spinning was performed under a positive voltage of 10.5 kV and a voltage of -1.5 kV. Hydroxyapatite fiber precursors were obtained on a collection plate. 5 g of the precursor was added to 25 mL of deionized water solvent, and 0.3 g of SnI2 was added. The mixture was stirred for 400 min to obtain a precursor mixture. The precursor mixture was dried in an oven at 80 °C for 30 h. After drying, the mixture was transferred to a muffle furnace, and the temperature of the muffle furnace was increased to 700 °C at a rate of 4 °C / min. The mixture was heat-treated at 700 °C for 8 h to obtain Sn. 2+ I - Co-doped porous hydroxyapatite fibers with a diameter of 300 nm and a length of 120 μm.

[0057] The Sn obtained above 2+ I - Co-doped porous hydroxyapatite fibers were ground and then passed through a 200-mesh sieve. 3.0 g of the sieved Sn was then collected. 2+ I - Co-doped porous hydroxyapatite fibers were added to 50 mL of propylene carbonate solvent and stirred for 45 min. Then, 1.0 g of LiAsF6 was added and stirred for another 45 min. Finally, 3.0 g of Li... 1.4 Al 0.4 Ti 1.6 (PO4)3 and 3.0 g of LiAl(PO4)(OH) 0.7 F 0.3 Stirring for 15 hours yields a suspension. The suspension is then cast and dried in a vacuum drying oven at 110°C for 3 hours. Finally, it is hot-pressed at 150°C for 120 minutes to obtain a hydroxyapatite fiber composite solid electrolyte with a thickness of 75 μm.

[0058] Example 5

[0059] 30 mL of anhydrous ethanol and 6 mL of deionized water were mixed, and 13.20 g of calcium nitrate tetrahydrate and 5.7 mL of triethyl phosphate were added. The mixture was stirred for 240 min until homogeneous. Then, 12 g of PVP was added, and the mixture was stirred at room temperature for 240 min to obtain a clear and transparent electrospinning solution. The electrospinning solution was transferred to a 20 mL syringe, and spinning was performed under a positive voltage of 10.0 kV and a voltage of -4.5 kV. Hydroxyapatite fiber precursors were obtained on a collection plate. 5 g of the precursor was added to 30 mL of anhydrous ethanol solvent, and 0.15 g of SnI2 was added. The mixture was stirred for 360 min to obtain a precursor mixture. The precursor mixture was dried in a drying oven at 200 °C for 6 h. After drying, the mixture was transferred to a muffle furnace, and the temperature of the muffle furnace was increased to 750 °C at a rate of 6 °C / min. The mixture was heat-treated at 750 °C for 8 h to obtain Sn. 2+ I - Co-doped porous hydroxyapatite fibers with a diameter of 400 nm and a length of 150 μm.

[0060] The Sn obtained above 2+ I - Co-doped porous hydroxyapatite fibers were ground and then passed through a 200-mesh sieve. 4.2 g of the sieved Sn was then collected. 2+ I - Co-doped porous hydroxyapatite fibers were added to 50 mL of butenyl carbonate solvent and stirred for 50 min. Then, 0.8 g of LiClO4 was added and stirred for 90 min. Finally, 5.0 g of Li7La3Zr2O4 was added. 12 Stirring for 6 hours yields a suspension, which is then cast and dried in a vacuum drying oven at 120°C for 3 hours. Finally, it is hot-pressed at 160°C for 30 minutes to obtain a hydroxyapatite fiber composite solid electrolyte with a thickness of 80 μm.

[0061] Example 6

[0062] 30 mL of anhydrous ethanol and 6 mL of deionized water were mixed, and 13.20 g of calcium nitrate tetrahydrate and 5.7 mL of triethyl phosphate were added. The mixture was stirred for 120 min until homogeneous. Then, 7 g of PVP was added, and the mixture was stirred at room temperature for 120 min to obtain a clear and transparent electrospinning solution. The electrospinning solution was transferred to a 20 mL syringe, and spinning was performed under a positive voltage of 11.5 kV and a voltage of -2.5 kV. Hydroxyapatite fiber precursors were obtained on a collection plate. 5 g of the precursor was added to 20 mL of anhydrous ethanol solvent, and 0.2 g of SnI2 was added. The mixture was stirred for 120 min to obtain a precursor mixture. The precursor mixture was dried in a drying oven at 150 °C for 15 h. After drying, the mixture was transferred to a muffle furnace, and the temperature of the muffle furnace was increased to 800 °C at a rate of 4 °C / min. The mixture was heat-treated at 800 °C for 10 h to obtain Sn.2+ I - Co-doped porous hydroxyapatite fibers with a diameter of 50 nm and a length of 70 μm.

[0063] The Sn obtained above 2+ I - Co-doped porous hydroxyapatite fibers were ground and then passed through a 200-mesh sieve. 3.5g of the sieved Sn was then collected. 2+ I - Co-doped porous hydroxyapatite fibers were added to 50 mL of dimethyl carbonate solvent and stirred for 150 min. Then, 0.35 g of LiBOB and 0.35 g of LiDFOB were added and stirred for another 50 min. Finally, 5.8 g of Li7La3Zr2O was added. 12 Stirring for 20 hours yields a suspension, which is then cast and dried in a vacuum drying oven at 110°C for 18 hours. Finally, it is hot-pressed at 90°C for 200 minutes to obtain a hydroxyapatite fiber composite solid electrolyte with a thickness of 50 μm.

[0064] Example 7

[0065] 30 mL of anhydrous ethanol and 6 mL of deionized water were mixed, and 13.20 g of calcium nitrate tetrahydrate and 5.7 mL of triethyl phosphate were added. The mixture was stirred for 240 min until homogeneous. Then, 10 g of PVP was added, and the mixture was stirred at room temperature for 240 min to obtain a clear and transparent electrospinning solution. The electrospinning solution was transferred to a 20 mL syringe, and spinning was performed under a positive voltage of 11.5 kV and a voltage of -2.5 kV. Hydroxyapatite fiber precursors were obtained on a collection plate. 5 g of the precursor was added to 20 mL of anhydrous ethanol solvent, and 0.3 g of SnI2 was added. The mixture was stirred for 360 min to obtain a precursor mixture. The precursor mixture was dried in a drying oven at 125 °C for 24 h. After drying, the mixture was transferred to a muffle furnace, and the temperature of the muffle furnace was increased to 850 °C at a rate of 4 °C / min. The mixture was heat-treated at 850 °C for 8 h to obtain Sn. 2+ I - Co-doped porous hydroxyapatite fibers with a diameter of 200 nm and a length of 150 μm.

[0066] The Sn obtained above 2+ I - Co-doped porous hydroxyapatite fibers were ground and then passed through a 200-mesh sieve. 4.7g of the sieved Sn was then collected. 2+ I - Co-doped porous hydroxyapatite fibers were added to 50 mL of acetonitrile solvent and stirred for 100 min. Then, 1.0 g of LiCF3SO3 was added and stirred for another 100 min. Finally, 5.3 g of Li... 0.33 La 0.557TiO3 was stirred for 20 hours to obtain a suspension. The suspension was then cast and dried in a vacuum drying oven at 80°C for 18 hours. Finally, it was hot-pressed at 100°C for 80 minutes to obtain a hydroxyapatite fiber composite solid electrolyte with a thickness of 60 μm.

[0067] Comparative Example 1

[0068] 30 mL of anhydrous ethanol and 6 mL of deionized water were mixed, and 13.20 g of calcium nitrate tetrahydrate and 5.7 mL of triethyl phosphate were added. The mixture was stirred for 240 min until homogeneous. Then, 6 g of PVP was added, and the mixture was stirred at room temperature for 240 min to obtain a clear and transparent electrospinning solution. The electrospinning solution was transferred to a 20 mL syringe, and spinning was performed under a positive voltage of 11.5 kV and a voltage of -2.5 kV. Hydroxyapatite fiber precursors were obtained on a collection plate. 5 g of the precursor was added to 20 mL of anhydrous ethanol solvent and stirred for 120 min to obtain a precursor mixture. The precursor mixture was dried in a drying oven at 100 °C for 24 h. After drying, the mixture was transferred to a muffle furnace, and the temperature of the muffle furnace was increased to 500 °C at a rate of 6 °C / min. The mixture was heat-treated at 500 °C for 18 h to obtain porous hydroxyapatite fibers with a diameter of 30 nm and a length of 400 μm.

[0069] The porous hydroxyapatite fibers obtained above were ground and passed through a 200-mesh sieve. 3.8 g of the sieved porous hydroxyapatite fibers were added to 40 mL of NMP solvent and stirred for 45 min. Then, 0.5 g of LiPF6 was added and stirred for another 45 min. Finally, 5.7 g of Li... 1.4 Al 0.4 Ti 1.6 (PO4)3 oxide conductive particles were stirred for 6 hours to obtain a suspension. The suspension was then cast and dried in a vacuum drying oven at 80°C for 6 hours. Finally, it was hot-pressed at 75°C for 60 minutes to obtain a hydroxyapatite fiber composite solid electrolyte with a thickness of 50 μm.

[0070] Comparative Example 2

[0071] Add 1.0 g of LiPF6 to 50 mL of NMP solvent and stir for 100 min. Then add 9.0 g of Li... 0.33 La 0.557 The TiO3 oxide conductive particles were stirred for another 20 hours to obtain a uniform suspension. Then, the suspension was cast and molded, kept at 80°C for 18 hours in a vacuum drying oven, and then hot-pressed at 100°C for 80 minutes to obtain a 60μm composite solid electrolyte.

[0072] Comparative Example 3

[0073] 30 mL of anhydrous ethanol and 6 mL of deionized water were mixed, and 13.20 g of calcium nitrate tetrahydrate and 5.7 mL of triethyl phosphate were added. The mixture was stirred for 360 min until homogeneous, resulting in a clear and transparent solution. The solution was dried in a drying oven at 120 °C for 12 h to obtain the precursor. 5 g of the precursor was added to 30 mL of anhydrous ethanol solvent, and 0.2 g of SnI4 was added. The mixture was stirred for 240 min to obtain the precursor mixture. The precursor mixture was dried in a drying oven at 150 °C for 18 h. After drying, it was transferred to a muffle furnace, and the temperature of the muffle furnace was increased to 550 °C at a rate of 5 °C / min. The mixture was heat-treated at 550 °C for 16 h to obtain Sn. 2+ I - Co-doped hydroxyapatite.

[0074] The Sn obtained above 2+ I - Co-doped hydroxyapatite was ground and then passed through a 200-mesh sieve. 4.0 g of the sieved Sn was then collected. 2+ I - Co-doped hydroxyapatite was added to 50 mL of ethylene carbonate solvent and stirred for 90 min. Then, 1.5 g of LiPF6 was added and stirred for another 90 min. Finally, 3.5 g of LiAl(PO4)(OH)2 was added. 0.4 F 0.6 The oxide conductive particles were stirred for 8 hours to obtain a suspension. The suspension was then cast and dried in a vacuum drying oven at 90°C for 12 hours. Finally, it was hot-pressed at 90°C for 90 minutes to obtain a hydroxyapatite composite solid electrolyte with a thickness of 70 μm.

[0075] The composite solid electrolytes prepared in Examples 1-7 and Comparative Examples 1-3 were stamped to obtain thin sheets with a diameter of 12 mm. The composite solid electrolytes were clamped between two stainless steel sheets and assembled into button cells. Their impedance was measured, and the ionic conductivity of the composite solid electrolyte was calculated using the formula ρ = L / SR, where L is the thickness of the solid electrolyte film (the average of three measurements for the same electrolyte film), S is the area of ​​the stainless steel clamp, and R is the measured impedance value. The test results of the ionic conductivity are shown in Table 1. As can be seen from Table 1, the composite solid electrolyte provided by this invention has excellent ionic conductivity.

[0076] The composite solid electrolytes prepared in Examples 1-7 and Comparative Examples 1-3 were used to prepare thin sheets with a diameter of 12 mm. The obtained composite solid electrolyte sheets were used to assemble Li symmetric batteries, and the interfacial impedance at room temperature was tested. The results are shown in Table 1. As can be seen from Table 1, the interfacial resistance of the positive and negative electrodes of the lithium-ion battery was significantly reduced, indicating that the composite solid electrolyte provided by the present invention has a low interfacial impedance and can enhance the conduction of lithium ions at the interface.

[0077] The composite solid electrolytes prepared in Examples 1-7 and Comparative Examples 1-3 were used to prepare sheets with a diameter of 12 mm. These sheets were then used to assemble Li / composite solid electrolyte / LiCoO2 batteries. The charge / discharge voltage was within the range of 3.0-4.45 V, and the batteries were charged and discharged at a rate of 0.1 C at room temperature. The initial discharge capacity and cycle stability of the coin cells assembled with the composite solid electrolyte were measured. The test results are shown in Table 1. As can be seen from Table 1, at a rate of 0.1 C, the initial charge / discharge capacity of the lithium-ion battery can reach more than 214.8 mAh / g, and the coulombic efficiency can reach more than 90%, indicating that the lithium-ion battery has good charge / discharge performance. After 200 cycles, the capacity retention rate is more than 83%, indicating that the lithium-ion battery has good cycle stability.

[0078] During the cyclic testing process, the battery could be charged and discharged normally without sparks or gas generation, indicating that the lithium-ion battery has good safety.

[0079] Table 1

[0080]

[0081]

[0082] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A hydroxyapatite fiber composite solid electrolyte, characterized in that, include: Sn 2+ and I - Co-doped porous hydroxyapatite fibers and oxide conductive particles supported on the porous hydroxyapatite fibers; the Sn 2+ The molar ratio of I to hydroxyapatite is 0.1~0.3:

1. - The molar ratio of hydroxyapatite to hydroxyapatite is 0.2~0.6:1; The oxide conductive particles are NASICON-type solid electrolytes, garnet-type solid electrolytes, perovskite-type solid electrolytes, and LiAl(PO4)(OH)2. 1-z F z ), where 0≤z≤1 or one or more of them.

2. The hydroxyapatite fiber composite solid electrolyte according to claim 1, characterized in that, The porous hydroxyapatite fiber has a diameter of 50~400 nm and a length of 30~150 μm.

3. The hydroxyapatite fiber composite solid electrolyte according to claim 1, characterized in that, The NASICON-type solid electrolyte is selected from Li 1+x Al x Ti 2-x (PO4)3, where 0 ≤ x ≤ 2; or Li 1+y Al y Ge 2-y (PO4)3, where 0 ≤ y ≤ 1 or one or more of these; The garnet-type solid electrolyte is selected from Li 7−m La3Zr 2−m Ta m O 12 where 0 ≤ m ≤ 2; The perovskite-type solid electrolyte is selected from Li 3a La 2 / 3-a TiO3, where 0 < a ≤ 0.

16.

4. The hydroxyapatite fiber composite solid electrolyte according to claim 3, characterized in that, The NASICON-type solid electrolyte is selected from Li 1.4 Al 0.4 Ti 1.6 (PO4)3 or Li 1.5 Al 0.5 Ge 1.5 (PO4)3; The LiAl(PO4)(OH 1-z F z Selected from LiAl(PO4)(OH) 0.4 F 0.6 ) or LiAl(PO4)(OH 0.7 F 0.3 ); The garnet-type solid electrolyte is selected from Li7La3Zr2O 12 ; The perovskite-type solid electrolyte is selected from Li 0.33 La 0.557 TiO3.

5. The hydroxyapatite fiber composite solid electrolyte according to claim 1, characterized in that, The Sn 2+ and I - The mass ratio of co-doped porous hydroxyapatite fibers to oxide conductive particles is 1:0.8~1.

8.

6. The hydroxyapatite fiber composite solid electrolyte according to claim 1, characterized in that, The composite solid electrolyte also includes lithium salt.

7. The hydroxyapatite fiber composite solid electrolyte according to claim 6, characterized in that, The lithium salt is selected from one or more of LiTFSI, LiFSI, LiCF3SO3, LiPF6, LiAsF6, LiClO4, LiDFOB and LiBOB.

8. The hydroxyapatite fiber composite solid electrolyte according to claim 6, characterized in that, The lithium salt and Sn 2 + and I - The mass ratio of co-doped porous hydroxyapatite fibers is 1:1.5~7.

6.

9. A method for preparing a hydroxyapatite fiber composite solid electrolyte as described in any one of claims 1 to 8, characterized in that, Includes the following steps: (a) Sn 2+ and I - A suspension was obtained by mixing co-doped porous hydroxyapatite fibers, lithium salts, and oxide conductive particles. (b) The suspension is cast, dried and hot-pressed to obtain hydroxyapatite fiber composite solid electrolyte.

10. A lithium-ion battery, characterized in that, The hydroxyapatite fiber composite solid electrolyte includes the hydroxyapatite fiber composite solid electrolyte according to any one of claims 1 to 8 or the hydroxyapatite fiber composite solid electrolyte prepared by the preparation method according to claim 9.

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