CN116969432B - Inorganic super-ion conductor material, preparation method and application thereof, inorganic solid electrolyte membrane and lithium battery - Google Patents

Abstract

The invention relates to the technical field of secondary batteries, and discloses an inorganic super-ion conductor material, a preparation method and application thereof, an inorganic solid electrolyte membrane and a lithium battery. The inorganic super-ion conductor material comprises hydroxyapatite and doped ions doped in the hydroxyapatite; wherein the doping ions are selected from at least one of metal cations and nonmetal anions. The invention also discloses a preparation method and application of the inorganic super-ion conductor material, an inorganic solid electrolyte membrane and a lithium battery. The inorganic super-ionic conductor material obtained by the invention has the advantages of high ionic conductivity, high mechanical strength, high flame retardance and the like, can be applied to lithium batteries and other secondary batteries, can be directly used as an inorganic solid electrolyte, can be added into a polymer matrix as an inorganic active filler to be used as a composite solid electrolyte, can be added into a positive electrode and a negative electrode to be used as a lithium-conducting active substance, can be used as an electrolyte additive, a diaphragm and the like, and can be applied to various components of the battery.

Description

Inorganic superionic conductor materials, preparation methods and applications thereof, inorganic solid electrolyte membranes and lithium batteries

Technical Field

The present invention relates to the technical field of secondary batteries, and in particular to an inorganic superionic conductor material and a preparation method and application thereof, an inorganic solid electrolyte membrane and a lithium battery.

Background technique

Lithium-ion batteries have been widely used since their commercialization and have become an irreplaceable energy storage device in human life. However, with the vigorous development of new energy devices such as portable electronic devices and new energy vehicles, higher requirements have been placed on the energy density and power density of lithium batteries.

At present, most commercial lithium-ion batteries use graphite based on intercalation reactions, which have good cycle life, but have the problem of low capacity and cannot meet the needs of lithium-ion batteries for further development in new energy vehicles, aerospace and other higher fields. Lithium metal has become the best choice for the negative electrode of future energy storage systems due to its ultra-high theoretical specific capacity (3860mAh g ^-1 ) and extremely low reduction potential (-3.04V vs. standard hydrogen electrode). Secondary batteries with lithium metal as the negative electrode have high specific energy (＞500Wh kg ^-1 ) and high energy density (＞1500Wh L ^-1 ). However, the use of volatile and combustible electrolytes will continuously react with metallic lithium, consume electrolytes and metallic lithium, form lithium dendrites, and pose huge safety risks.

In order to effectively solve the above problems, solid electrolytes are used instead of traditional electrolytes to alleviate battery safety and thermal stability, while also making it possible to use metallic lithium as the negative electrode of the battery, thereby achieving the goal of further improving energy density.

Solid electrolytes are divided into inorganic solid electrolytes, polymer solid electrolytes and composite solid electrolytes. Inorganic solid electrolytes have high ionic conductivity and high mechanical strength, but there are problems with the interface contact with the electrode; polymer solid electrolytes have high flexibility and good interface contact with the electrode, but the disadvantage is low ionic conductivity; composite solid electrolytes combine the advantages of inorganic and polymer solid electrolytes, and have high ionic conductivity, high mechanical strength, high flexibility and good interface contact with the electrode.

At present, there is an urgent need in this field to develop a material with high ionic conductivity, high mechanical strength and high flame retardancy.

Summary of the invention

The purpose of the present invention is to overcome the problems existing in the prior art and to provide an inorganic superionic conductor material and a preparation method and application thereof, an inorganic solid electrolyte membrane and a lithium battery.

In order to achieve the above-mentioned purpose, the first aspect of the present invention provides an inorganic superionic conductor material, wherein the inorganic superionic conductor material comprises hydroxyapatite and doped ions doped in the hydroxyapatite; wherein the doped ions are selected from at least one of metal cations and non-metal anions.

The second aspect of the present invention provides a method for preparing the inorganic superionic conductor material according to the first aspect, wherein the method is selected from a hydrothermal method, a solid phase method and a solution stirring method.

The third aspect of the present invention provides an inorganic superionic conductor material prepared according to the preparation method described in the second aspect.

The fourth aspect of the present invention provides the use of the inorganic superionic conductor material described in the first aspect or the third aspect in the preparation of lithium batteries and other secondary batteries.

The fifth aspect of the present invention provides an inorganic solid electrolyte membrane made from the inorganic superionic conductor material described in the first aspect or the third aspect.

A sixth aspect of the present invention provides a lithium battery comprising the inorganic solid electrolyte membrane described in the fifth aspect.

Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows:

(1) The inorganic superionic conductor material provided by the present invention is prepared by doping ions in hydroxyapatite, replacing part of the calcium ions therein with lithium ions, magnesium ions, zinc ions, sodium ions, potassium ions, chromium ions, etc., so as to convert the hydroxyapatite into an active filler that can conduct lithium itself, thereby increasing lithium ion transmission channels inside the material; replacing part of the hydroxide ions therein with fluoride ions, chloride ions, bromide ions, carbonate ions, etc., thereby promoting the dissociation of lithium salts and increasing lithium ion transmission channels on the surface of the material.

(2) The present invention can not only independently synthesize hydroxyapatite, but also extract hydroxyapatite from bones or directly use commercial hydroxyapatite products, and by regulating the preparation method, synthesis time, synthesis temperature and other conditions, anion- and cation-co-doped hydroxyapatite in the form of nanoparticles, nanowires, nanosheets and the like can be prepared as an inorganic superionic conductor material.

(3) The nanowire structure with ultra-high aspect ratio synthesized by the hydrothermal method of the present invention can greatly improve the ionic conductivity, and at the same time has high mechanical strength and high flame retardancy, which can effectively inhibit safety issues such as lithium dendrite growth and thermal runaway. When used as an inorganic solid electrolyte, it has a high electrochemical window and high ionic conductivity under optimal conditions. The assembled symmetrical battery can be stably cycled for 1500-2000h, and the overpotential is stable below 100mV, indicating that the solid electrolyte has excellent ion transmission ability, and the assembled full battery has high specific capacity, excellent cycle stability and rate performance.

(4) The inorganic superionic conductor material provided by the present invention can be applied to lithium batteries and other secondary batteries, and can be used as composite solid electrolyte fillers, positive and negative electrode additives, electrolyte additives and diaphragms in various components of batteries. The preparation method of the present invention is simple and controllable, the preparation process is environmentally friendly and low-cost, and provides a new idea for the large-scale preparation and application of low-cost, renewable and high-performance inorganic superionic conductor materials.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a scanning electron microscope image of the inorganic superionic conductor material prepared in Example 1 of the present invention;

FIG2 is a transmission electron microscope image of the inorganic superionic conductor material prepared in Example 1 of the present invention;

3 is a stress-strain curve diagram of the inorganic solid electrolyte membrane prepared in Example 1 of the present invention;

FIG4 is a linear sweep voltammetry curve of the inorganic solid electrolyte membrane prepared in Example 1 of the present invention;

5 is an Arrhenius curve diagram of the inorganic solid electrolyte membrane prepared in Example 1 of the present invention;

FIG6 is a cycle performance diagram of a symmetrical battery assembled with an inorganic solid electrolyte membrane prepared in Example 1 of the present invention;

7 is a rate performance diagram of a full cell assembled with an inorganic solid electrolyte membrane prepared in Example 1 of the present invention at step currents of 0.1, 0.2, 0.3, 0.4, 0.5, and 1C;

FIG8 is a graph showing the cycling performance of a full battery assembled with an inorganic solid electrolyte membrane prepared in Example 1 of the present invention at a current density of 0.2C.

Detailed ways

The endpoints and any values of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article.

A first aspect of the present invention provides an inorganic superionic conductor material, wherein the inorganic superionic conductor material comprises hydroxyapatite and doping ions doped in the hydroxyapatite;

Wherein, the doping ions are selected from at least one of metal cations and non-metal anions.

Hydroxyapatite, with the general formula of Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ , is the main inorganic component of vertebrate bones and teeth and has good biocompatibility, flame retardancy and ion exchange capacity.

The present invention utilizes the strong ion exchange property of hydroxyapatite, and by doping at least one of metal cations and non-metal anions in hydroxyapatite, two lithium ion transmission channels are added inside and on the surface of the material, thereby greatly improving the ion conductivity.

The present invention utilizes the strong ion exchange capacity of hydroxyapatite to replace part of the calcium ions with metal ions such as lithium ions, sodium ions, potassium ions, magnesium ions, zinc ions, etc., add lithium ion transmission channels inside the material, and convert the inert filler into an active filler; replace part of the hydroxide ions with anions such as fluoride ions, chloride ions, bromide ions, carbonate ions, etc., add lithium ion transmission channels on the surface of the material, and prepare a new inorganic superionic conductor material with internal and surface lithium ion transmission dual channels. The inorganic superionic conductor material of the present invention can be applied to lithium batteries and other secondary batteries, and can be directly used as an inorganic solid electrolyte. The assembled battery has high specific capacity, good cycle stability and rate performance. It can also be added to the polymer matrix as an active filler and used as a composite solid electrolyte, positive and negative electrode additives, electrolyte additives, diaphragms, etc. for various components of the battery.

In some embodiments of the present invention, the metal cation is selected from at least one of lithium ion, sodium ion, potassium ion, magnesium ion, zinc ion, chromium ion, aluminum ion, barium ion, chromium ion, lead ion and mercury ion, preferably lithium ion.

In some embodiments of the present invention, the non-metallic anion is selected from at least one of fluoride ion, chloride ion, bromide ion, carbonate ion and sulfate ion, preferably fluoride ion.

In some embodiments of the present invention, the doping ions include metal cations and non-metal anions, preferably lithium ions and fluoride ions.

In some embodiments of the present invention, the molar ratio of calcium ions to metal cations in the hydroxyapatite is 2-10, preferably 5-7.5.

In some embodiments of the present invention, the molar ratio of metal cations to non-metal anions in the doping ions is 0.5-3, preferably 0.86-1.23.

In some embodiments of the present invention, the morphology of the inorganic superionic conductor material is selected from one of nanoparticles, nanowires and nanosheets.

In some embodiments of the present invention, the average particle size of the nanoparticles is 20-800 nm, preferably 40-100 nm.

In some embodiments of the present invention, the aspect ratio of the nanowire is 100-50000:1, preferably 40000-50000:1.

In some embodiments of the present invention, the size of the nanosheet is 500 nm-5 μm, preferably 500 nm-2 μm; the thickness is 20-1000 nm, preferably 200-500 nm.

The second aspect of the present invention provides a method for preparing the inorganic superionic conductor material according to the first aspect, wherein the method is selected from a hydrothermal method, a solid phase method and a solution stirring method.

The present invention uses a hydrothermal method, a solid phase method or a solution stirring method to select metal cations and non-metal anions to replace calcium ions and hydroxyls in hydroxyapatite, thereby obtaining an inorganic superionic conductor material with high ionic conductivity, high mechanical strength and high flame retardancy. The inorganic superionic conductor material utilizes the strong ion exchange effect of hydroxyapatite, and the calcium ions are exchanged with metal ions to convert the inert non-lithium-conducting material into an active material that can conduct lithium itself. Through the exchange of hydroxide and non-metallic anions, a new ion rapid transmission channel is added on the surface of hydroxyapatite, and the rapid transmission of ions inside and on the surface of the material is realized at the same time, and the inorganic superionic conductor material has high ionic conductivity and ensures the rapid transmission of lithium ions.

In some embodiments of the present invention, the hydrothermal method comprises the following steps:

(1) mixing a calcium source, a dispersant and water to obtain a mixed solution;

(2) adjusting the pH of the mixed solution to 5-11, adding a soluble metal ion salt solution and a phosphorus source thereto for a second mixing to obtain a precursor solution;

(3) subjecting the precursor solution to a microwave hydrothermal reaction, and cooling the reaction product, washing it, and dispersing it in water;

(4) adding anion salt to the product obtained in step (3) for a third mixing, and then filtering, washing and drying to obtain the inorganic superionic conductor material.

The washing may be water washing or alcohol washing, and may be performed by centrifugation.

In some embodiments of the present invention, the solid phase method comprises the following steps:

(1') mixing hydroxyapatite powder and metal ion salt powder and calcining;

(2') soaking the powder obtained after calcination in step (1') in water;

(3') The product after immersion in step (2') is filtered, washed and dried to obtain the inorganic superionic conductor material.

The washing may be water washing.

In some embodiments of the present invention, the solution stirring method comprises the following steps:

(1") mixing hydroxyapatite powder with a soluble metal ion salt solution;

(2") The mixed solution obtained in step (1") is filtered, washed and dried to obtain the inorganic superionic conductor material.

The washing may be water washing.

In some embodiments of the present invention, in the hydrothermal method, the calcium source in step (1) is selected from at least one of anhydrous calcium chloride, calcium carbonate, calcium bicarbonate and calcium nitrate.

In some embodiments of the present invention, the dispersant is selected from at least one of sodium oleate, glutamic acid and alanine.

In some embodiments of the present invention, relative to 40-100 mL of solvent, the amount of the calcium source is 0.113-0.444 g, and the amount of the dispersant is 2-5 g.

In some embodiments of the present invention, the first mixing time is 30 min-4 h, preferably 1-2 h.

In some embodiments of the present invention, in step (1), the calcium source and the dispersant are respectively dissolved in water to form a solution, and then a first mixing is performed.

In some embodiments of the present invention, the amount of the calcium source is 0.113-0.444 g relative to 20-50 mL of water.

In some embodiments of the present invention, the amount of the dispersant is 2-5 g relative to 20-50 mL of water.

In some embodiments of the present invention, the pH value in step (2) is 10.

In some embodiments of the present invention, the soluble metal ion salt in the soluble metal ion salt solution is selected from at least one of lithium nitrate, lithium sulfate, lithium chloride, magnesium nitrate, magnesium chloride, zinc nitrate, zinc chloride, copper nitrate, copper chloride, chromium chloride and nickel sulfate, preferably lithium nitrate.

In some embodiments of the present invention, the phosphorus source is selected from at least one of sodium dihydrogen phosphate, sodium hydrogen phosphate, calcium hydrogen phosphate and calcium phosphate, preferably sodium dihydrogen phosphate.

In some embodiments of the present invention, the molar ratio of the calcium source to the soluble metal ion salt in the soluble metal ion salt solution is 2-10, preferably 5-7.5, calculated as metal ions and calcium ions respectively.

In some embodiments of the present invention, relative to 0.133 g of soluble metal ion salt, the amount of the phosphorus source is 0.4-0.7 g, preferably 0.55-0.68 g.

In some embodiments of the present invention, the second mixing time is 30 min-4 h, preferably 1-2 h.

In some embodiments of the present invention, the conditions of the microwave hydrothermal reaction in step (3) include: a reaction temperature of 100-500° C., preferably 100-300° C.; and a reaction time of 1-12 h, preferably 2-6 h.

In some embodiments of the present invention, the non-metallic anion salt is selected from at least one of sodium fluoride, sodium carbonate, sodium chloride, ammonium chloride, ammonium fluoride and sodium bromide, preferably sodium fluoride.

In some embodiments of the present invention, relative to 0.133 g of soluble metal ion salt, the amount of the non-metallic anion salt is 0.05-0.4 g, preferably 0.1-0.2 g.

In some embodiments of the present invention, the third mixing time is 4-24 hours, preferably 8-12 hours.

In some embodiments of the present invention, the drying conditions include: a temperature of 20-100° C., preferably 40-80° C.; and a time of 4-24 h, preferably 12-16 h.

The preparation of inorganic superionic conductor materials based on hydroxyapatite by a hydrothermal method can precisely control the amount of metal cations and/or non-metallic anions doped therein to obtain materials with different microscopic morphologies.

The anion-cation co-doped hydroxyapatite prepared by the hydrothermal method is an ultra-long nanowire structure with an ultra-high aspect ratio, which is interwoven to form a continuous and stable ion transport network structure, and has high ionic conductivity and mechanical strength; hydroxyapatite has excellent flame retardant properties and can improve the safety of the material.

In some embodiments of the present invention, in the solid phase method and the solution stirring method, the hydroxyapatite powder is selected from at least one of commercial spherical or needle-shaped hydroxyapatite and hydroxyapatite extracted from cattle bones, pig bones, sheep bones, fish scales, and crab shells.

In some embodiments of the present invention, in the solid phase method, the metal ion salt powder is selected from at least one of lithium fluoride, lithium nitrate, lithium sulfate, lithium chloride, sodium chloride, sodium fluoride, sodium carbonate, sodium sulfate, sodium nitrate, sodium bromide, potassium carbonate, potassium chloride, potassium bromide, potassium fluoride, potassium nitrate, magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium carbonate, zinc nitrate, zinc sulfate, zinc chloride and ammonium chloride, preferably lithium fluoride.

In some embodiments of the present invention, in the solution stirring method, the soluble metal ion salt in the soluble metal ion salt solution is selected from at least one of lithium fluoride, lithium nitrate, lithium sulfate, lithium chloride, sodium chloride, sodium fluoride, sodium carbonate, sodium sulfate, sodium nitrate, sodium bromide, potassium carbonate, potassium chloride, potassium bromide, potassium fluoride, potassium nitrate, magnesium nitrate, magnesium sulfate, magnesium chloride, zinc nitrate, zinc sulfate, zinc chloride, ammonium chloride, copper nitrate and copper chloride, preferably lithium fluoride.

In some embodiments of the present invention, the mass ratio of the hydroxyapatite powder to the metal ion salt powder in step (1') is 10:1-1:50, preferably 1:4.8.

In some embodiments of the present invention, the calcination conditions include: a calcination temperature of 200-1200° C., preferably 600-900° C.; and a calcination time of 1-10 h, preferably 3-8 h.

In some embodiments of the present invention, the soaking time in step (2') is 4-24 hours, preferably 12 hours.

In some embodiments of the present invention, the drying conditions in step (3') include: a drying temperature of 20-80°C, preferably 60°C; and a drying time of 6-24h, preferably 24h.

In some embodiments of the present invention, the mass ratio of the hydroxyapatite powder to the soluble metal ion salt in the soluble metal ion salt solution in step (1") is 10:1-1:20, preferably 1:9.5.

In some embodiments of the present invention, the mixing conditions in step (1") include: a mixing temperature of 20-150°C, preferably 20-60°C; and a mixing time of 1-24h, preferably 6-12h.

In some embodiments of the present invention, the drying conditions in step (2") include: a drying temperature of 20-100°C, preferably 60°C; and a drying time of 6-24h, preferably 24h.

The present invention can synthesize hydroxyapatite independently, extract hydroxyapatite from bones or directly use commercial hydroxyapatite products, and prepare anion-cation co-doped hydroxyapatite in the form of nanoparticles, nanowires, nanosheets, etc. by adjusting the preparation method, synthesis time, synthesis temperature and other conditions. Among them, the nanowire structure with ultra-high aspect ratio prepared by hydrothermal method can greatly improve the ion conductivity, and at the same time has high mechanical strength and high flame retardancy. The battery assembled with inorganic solid electrolyte has the advantages of high specific capacity, long cycle life, high safety, etc., and can also be used as composite solid electrolyte filler, positive and negative electrode additives, electrolyte additives and diaphragms in various components of the battery.

The third aspect of the present invention provides an inorganic superionic conductor material prepared according to the preparation method described in the second aspect.

The fourth aspect of the present invention provides the use of the inorganic superionic conductor material described in the first aspect or the third aspect in the preparation of lithium batteries and other secondary batteries; preferably, the inorganic superionic conductor material is used in the preparation of inorganic solid electrolytes, composite solid electrolytes, positive and negative electrode materials, diaphragms and electrolytes.

The inorganic superionic conductor material obtained by the present invention has the advantages of high ionic conductivity, high mechanical strength, high flame retardancy, etc. It can be directly used as an inorganic solid electrolyte, or can be added as an inorganic active filler into a polymer matrix for use as a composite solid electrolyte, added into positive and negative electrodes as a lithium-conducting active substance, as an electrolyte additive and a diaphragm, etc., and can be applied to various components of a battery to improve battery performance.

The fifth aspect of the present invention provides an inorganic solid electrolyte membrane made of the inorganic superionic conductor material of the first aspect or the third aspect. The inorganic solid electrolyte membrane has an ion conductivity of 1×10 ^-6 -2×10 ^-2 S cm ^-1 , a tensile strength of 0.5-15 MPa, and retains its original morphology after ignition for 500 seconds.

The inorganic solid electrolyte membrane can be prepared by the following method: the inorganic superionic conductor material obtained above is dispersed in water, and the inorganic solid electrolyte membrane is prepared by vacuum filtration.

A sixth aspect of the present invention provides a lithium battery comprising the inorganic solid electrolyte membrane described in the fifth aspect.

Batteries assembled with inorganic solid electrolyte membranes exhibit high specific capacity, excellent cycle stability and rate performance.

The present invention will be described in detail below through examples.

In the following examples and comparative examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if no manufacturer is specified, are conventional products that can be obtained through commercial channels.

Test Methods:

Mechanical properties (tensile strength) test: The tensile speed is 500 mm/min. The sample is cut into dumbbell-shaped splines, clamped between fixtures, and the thickness, width and length of the spline working area are input to perform a tensile strength test.

Ionic conductivity test: The solid electrolyte membrane was sandwiched between two stainless steel gaskets and connected to an electrochemical workstation for impedance testing at a frequency of 1MHz-0.1Hz.

Electrochemical performance test: assemble symmetrical cells and full cells for testing and analysis. The entire process of assembling the battery must be carried out in a glove box filled with argon. The symmetrical cell assembly process is: place the negative electrode shell, lithium sheet, solid electrolyte membrane, lithium sheet, and positive electrode shell in sequence, put them into a packaging machine and pressurize them to 50MPa; the full cell assembly process is: place the negative electrode shell, lithium sheet, solid electrolyte membrane, lithium iron phosphate, and positive electrode shell in sequence, put them into a packaging machine and pressurize them to 50MPa.

Symmetrical battery test: At a current density of 0.1 mA cm ^-2 , charge for 1 hour, discharge for 1 hour, and cycle.

Rate performance test: The full battery is subjected to constant current charge and discharge test analysis under step current density, and the test conditions are: voltage range 2.5-4.2V.

Reversible specific capacity and cycle performance test: The full battery is subjected to constant current charge and discharge test analysis. The test conditions are: voltage range 2.5-4.2V, current density 0.2C.

Example 1

This example is used to illustrate the preparation of inorganic superionic conductor materials by a hydrothermal method.

Weigh 0.331g of anhydrous calcium chloride and dissolve it in 40mL of water, and dissolve 4.8g of sodium oleate in 50mL of water, respectively, stir until dissolved, and mix and stir for 1h; adjust the pH to 10, add 50mL of a solution containing 0.56g of sodium dihydrogen phosphate, mix and stir for 30min, then add 0.133g of lithium nitrate, and stir for 1h to obtain a precursor solution; put the precursor solution into a microwave hydrothermal reactor, keep it at 200℃ for 4h, cool the reaction product to room temperature, and disperse it in water after washing with water and alcohol; add 0.2g of sodium fluoride to the product, stir at room temperature for 12h, wash with water, filter, and dry at 60℃ for 12h to obtain an inorganic superionic conductor material. Its scanning electron microscope image and transmission electron microscope image are shown in Figures 1 and 2, respectively, and it is a nanowire structure with an ultra-high aspect ratio.

The inorganic superionic conductor material obtained above was dispersed in water, and an inorganic solid electrolyte membrane was prepared by vacuum filtration to test the tensile strength and ionic conductivity. The results showed that it had a tensile strength of up to 9.66MPa (Figure 3), an electrochemical window of up to 5.4V (Figure 4), and an ionic conductivity of up to 1.2× ^10-2 S cm ^-1 (Figure 5).

The electrochemical performance test results show that the assembled symmetrical battery can be stably cycled for 2000 hours, and the overpotential is stable at 50mV (Figure 6).

Full batteries were assembled for testing. At step current densities of 0.1, 0.2, 0.3, 0.4, 0.5, and 1.0C, the reversible specific capacities were 165.2, 152.7, 143.4, 129.8, 120.1, and 112.3 mAh g ^-1 , respectively. The specific capacity could also be restored when the current density returned to a low level of 0.2C ( FIG7 ).

It can stably cycle 500 times at a current density of 0.2C, and the capacity retention rate is 83.4% (Figure 8).

Example 2

This example is used to illustrate the preparation of inorganic superionic conductor materials by a hydrothermal method.

The operating conditions were the same as those in Example 1, except that lithium nitrate was not added to the precursor solution.

The obtained inorganic solid electrolyte membrane had a tensile strength of 9.89 MPa and an ionic conductivity of 9.64×10 ^-5 S cm ^-1 .

The electrochemical performance test results show that the assembled symmetrical battery can be stably cycled for 2000 hours, and the overpotential is stable at 100mV.

The whole battery was assembled for testing. At a current density of 0.2C, the capacity retention rate was 77.9% after 100 cycles. The reversible specific capacities at the same step current density were 147.8, 113.2, 87.1, 65.8, 55.1, and 48.5 mAh g ^-1 , respectively.

Example 3

This example is used to illustrate the preparation of inorganic superionic conductor materials by a hydrothermal method.

The operating conditions were the same as those in Example 1, except that sodium fluoride was not added for stirring at room temperature after the microwave hydrothermal reaction was completed.

The obtained inorganic solid electrolyte membrane had a tensile strength of 9.57 MPa and an ionic conductivity of 1.08×10 ^-4 S cm ^-1 .

The electrochemical performance test results show that the assembled symmetrical battery can be stably cycled for 2000 hours, and the overpotential is stable at 80mV.

The whole battery was assembled for testing. At a current density of 0.2C, the capacity retention rate was 74.2% after 120 cycles. The reversible specific capacities at the same step current density were 159.2, 136.9, 98.1, 78.3, 66.5, and 52.8 mAh g ^-1 , respectively.

Example 4

This example is used to illustrate the preparation of inorganic superionic conductor materials by a hydrothermal method.

The operating conditions were the same as in Example 1, except that the pH was adjusted to 11.

The obtained inorganic solid electrolyte membrane had a tensile strength of 8.27 MPa and an ionic conductivity of 1.5×10 ^-4 S cm ^-1 .

The electrochemical performance test results show that the assembled symmetrical battery can be cycled stably for 2000 hours, and the overpotential is stable at 80mV.

The whole battery was assembled for testing. At a current density of 0.2C, the capacity retention rate was 72.2% after 200 cycles. The reversible specific capacities at the same step current density were 136.5, 112.2, 97.6, 77.5, 63.7, and 50.1 mAh g ^-1 , respectively.

Comparative Example 1

The operating conditions were the same as those in Example 1, except that lithium nitrate was not added to the hydroxyapatite precursor solution, and sodium fluoride was not added for stirring at room temperature after the microwave hydrothermal reaction was completed.

The obtained inorganic solid electrolyte membrane had a tensile strength of 8.06 MPa and an ionic conductivity of 1.0×10 ^-5 S cm ^-1 .

The results of electrochemical performance tests show that when the assembled symmetrical battery is tested, the overpotential continues to increase and a short circuit will occur after 100 hours of cycling.

The whole battery was assembled for testing. At a current density of 0.2C, the capacity decayed rapidly to 0 after 70 cycles. The reversible specific capacities at the same step current density were 121.6, 108.9, 86.2, 64.6, 49.8, and 36.7 mAh g ^-1 , respectively.

Example 5

This example is used to illustrate the preparation of inorganic superionic conductor materials by a solid phase method.

Weigh 126 mg of hydroxyapatite powder and 0.6 g of lithium fluoride, mix them and put them into a tubular furnace, pass inert gas, calcine at 900°C for 4 hours, cool to room temperature, put them into deionized water, soak them for 12 hours, filter and wash them with water, and dry them at 60°C for 24 hours to obtain an inorganic superionic conductor material.

The inorganic superionic conductor material obtained above was dispersed in water, and an inorganic solid electrolyte membrane was prepared by vacuum filtration to test the tensile strength and ionic conductivity.

The obtained inorganic solid electrolyte membrane had a tensile strength of 3.54 MPa and an ionic conductivity of 1.9×10 ^-4 S cm ^-1 .

The electrochemical performance test results show that the assembled symmetrical battery can be cycled stably for 1500 hours, and the overpotential is stable at 70mV.

The whole battery was assembled and tested. At a current density of 0.2C, the capacity retention rate was 75.2% after 500 cycles. The reversible specific capacities at the same step current density were 147.8, 123.1, 109.7, 90.3, 86.2, and 62.7 mAh g ^-1 , respectively.

Example 6

The operating conditions were the same as in Example 5, except that the calcination temperature was 1000°C.

The obtained inorganic solid electrolyte membrane had a tensile strength of 7.22 MPa and an ionic conductivity of 1.4×10 ^-4 S cm ^-1 .

The electrochemical performance test results show that the assembled symmetrical battery can be cycled stably for 1500 hours, and the overpotential is stable at 80mV.

The whole battery was assembled and tested. At a current density of 0.2C, the capacity retention rate was 77.5% after 500 cycles. The reversible specific capacities at the same step current density were 136.9, 123.1, 109.7, 97.3, 89.2, and 65.5 mAh g ^-1 , respectively.

Example 7

This example is used to illustrate the preparation of inorganic superionic conductor materials by a solution stirring method.

1.2 g of lithium fluoride was weighed and dissolved in 60 mL of deionized water, 126 mg of hydroxyapatite powder was added, and the mixture was stirred at 45° C. for 12 h. The mixture was filtered and washed with water, and dried at 60° C. for 24 h to obtain an inorganic superionic conductor material.

The inorganic superionic conductor material obtained above was dispersed in water, and an inorganic solid electrolyte membrane was prepared by vacuum filtration to test the tensile strength and ionic conductivity.

The obtained inorganic solid electrolyte membrane had a tensile strength of 5.23 MPa and an ionic conductivity of 2.1×10 ^-4 S cm ^-1 .

The electrochemical performance test results show that the assembled symmetrical battery can be stably cycled for 1500 hours, and the overpotential is stable at 60mV.

The whole battery was assembled for testing. At a current density of 0.2C, the capacity retention rate after 500 cycles was 79.3%. The reversible specific capacities at step current densities were 132.9, 113.7, 106.2, 80.1, 79.6, and 55.4 mAh g ^-1 , respectively.

Example 8

The operating conditions were the same as in Example 7, except that the mixing and stirring time was 8 h.

The obtained inorganic solid electrolyte membrane had a tensile strength of 4.97 MPa and an ionic conductivity of 1.9×10 ^-4 S cm ^-1 .

The electrochemical performance test results show that the assembled symmetrical battery can be cycled stably for 1500 hours, and the overpotential is stable at 100mV.

At a current density of 0.2C, the capacity retention rate after 500 cycles is 78.5%, and the reversible specific capacities at step current densities are 136.7, 119.2, 96.6, 75.1, and 63.2 mAh g ^-1 , respectively.

It can be seen from the above embodiments that by utilizing the strong ion exchange effect of hydroxyapatite to replace part of the calcium ions with lithium ions and part of the hydroxide ions with fluoride ions, fast lithium conduction channels can be introduced into the fiber interior and surface at the same time, and the obtained lithium-fluorine co-doped hydroxyapatite network structure with an ultra-high aspect ratio nanowire structure has the advantages of high ionic conductivity, high mechanical strength, high flame retardancy, wide voltage window, etc. The assembled battery has excellent rate performance and long cycle life, and has good application prospects as a solid electrolyte material.

The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims (43)

1. An inorganic superionic conductor material, characterized in that the inorganic superionic conductor material is composed of hydroxyapatite and metal cations and non-metallic anions doped in the hydroxyapatite; Wherein, the molar ratio of calcium ions to metal cations in the hydroxyapatite is 1.5; The molar ratio of the metal cation to the non-metal anion is 0.4; The metal cation is selected from at least one of lithium ion, sodium ion, potassium ion, magnesium ion, zinc ion, chromium ion, aluminum ion, barium ion, chromium ion, lead ion and mercury ion; The non-metallic anion is selected from at least one of fluoride ion, chloride ion, bromide ion, carbonate ion and sulfate ion. The material according to claim 1 , wherein the metal cation is a lithium ion. The material according to claim 1 , wherein the non-metal anion is a fluoride ion. 4. The material according to any one of claims 1 to 3, wherein the morphology of the inorganic superionic conductor material is selected from one of nanoparticles, nanowires and nanosheets. The material according to claim 4 , wherein the average particle size of the nanoparticles is 20-800 nm. The material according to claim 5 , wherein the average particle size of the nanoparticles is 40-100 nm. 7. The material according to claim 4, wherein the aspect ratio of the nanowires is 100-50000:1. 8. The material according to claim 7, wherein the aspect ratio of the nanowire is 40000-50000:1. 9. The material according to claim 4, wherein the size of the nanosheets is 500 nm-5 μm; and the thickness is 20-1000 nm. 10. The material according to claim 9, wherein the size of the nanosheets is 500 nm-2 μm; and the thickness is 200-500 nm. 11. A method for preparing an inorganic superionic conductor material according to any one of claims 1 to 10, characterized in that the method is a hydrothermal method. 12. The preparation method according to claim 11, wherein the hydrothermal method comprises the following steps: (1) mixing a calcium source, a dispersant and water to obtain a mixed solution; (2) adjusting the pH of the mixed solution to 5-11, adding a soluble metal ion salt solution and a phosphorus source thereto for a second mixing to obtain a precursor solution; (3) subjecting the precursor solution to a microwave hydrothermal reaction, and cooling the reaction product, washing it, and dispersing it in water; (4) Adding a non-metallic anion salt to the product obtained in step (3) for a third mixing, and then filtering, washing, and drying to obtain the inorganic superionic conductor material. 13. The preparation method according to claim 12, wherein, in the hydrothermal method, the calcium source in step (1) is selected from at least one of anhydrous calcium chloride, calcium carbonate, calcium bicarbonate and calcium nitrate. 14. The preparation method according to claim 12, wherein the dispersant is selected from at least one of sodium oleate, glutamic acid and alanine. 15. The preparation method according to claim 12, wherein, relative to 40-100 mL of the solvent, the amount of the calcium source is 0.113-0.444 g, and the amount of the dispersant is 2-5 g. The preparation method according to claim 12 , wherein the first mixing time is 30 min-4 h. The preparation method according to claim 16 , wherein the first mixing time is 1-2 h. 18. The preparation method according to claim 12, wherein in step (1), the calcium source and the dispersant are respectively dissolved in water to form a solution, and then a first mixing is performed. 19. The preparation method according to claim 12, wherein the amount of the calcium source is 0.113-0.444 g relative to 20-50 mL of water. 20. The preparation method according to claim 12, wherein the amount of the dispersant is 2-5 g relative to 20-50 mL of water. 21. The preparation method according to claim 12, wherein the pH value in step (2) is 10. 22. The preparation method according to claim 12, wherein the soluble metal ion salt in the soluble metal ion salt solution is selected from at least one of lithium nitrate, lithium sulfate, lithium chloride, magnesium nitrate, magnesium chloride, zinc nitrate, zinc chloride, copper nitrate, copper chloride, chromium chloride and nickel sulfate. 23. The preparation method according to claim 22, wherein the soluble metal ion salt is lithium nitrate. 24. The preparation method according to claim 12, wherein the phosphorus source is selected from at least one of sodium dihydrogen phosphate, sodium hydrogen phosphate, calcium hydrogen phosphate and calcium phosphate. The preparation method according to claim 24 , wherein the phosphorus source is sodium dihydrogen phosphate. 26. The preparation method according to claim 12, wherein the amount of the phosphorus source is 0.4-0.7 g relative to 0.133 g of the soluble metal ion salt. The preparation method according to claim 12 , wherein the second mixing time is 30 min-4 h. The preparation method according to claim 27 , wherein the second mixing time is 1-2 h. 29. The preparation method according to claim 12, wherein the conditions of the microwave hydrothermal reaction in step (3) include: a reaction temperature of 100-500°C; and a reaction time of 1-12 h. 30. The preparation method according to claim 29, wherein the conditions of the microwave hydrothermal reaction in step (3) include: a reaction temperature of 100-300°C; and a reaction time of 2-6 h. 31. The preparation method according to claim 12, wherein the non-metallic anion salt is selected from at least one of sodium fluoride, sodium carbonate, sodium chloride, ammonium chloride, ammonium fluoride and sodium bromide. 32. The preparation method according to claim 31, wherein the non-metallic anion salt is sodium fluoride. 33. The preparation method according to claim 12, wherein the amount of the non-metallic anion salt is 0.05-0.4 g relative to 0.133 g of the soluble metal ion salt. The preparation method according to claim 12 , wherein the third mixing time is 4-24 h. The preparation method according to claim 34 , wherein the third mixing time is 8-12 h. 36. The preparation method according to claim 12, wherein the drying conditions include: temperature of 20-100°C; time of 4-24 h. 37. The preparation method according to claim 36, wherein the drying conditions include: temperature of 40-80°C and time of 12-16 h. 38. An inorganic superionic conductor material obtained by the preparation method according to any one of claims 11-37. 39. Use of the inorganic superionic conductor material according to any one of claims 1 to 10 and 38 in the preparation of lithium batteries and other secondary batteries. 40. The use according to claim 39, wherein the inorganic superionic conductor material is used in the preparation of inorganic solid electrolytes, composite solid electrolytes, positive and negative electrode materials, separators and electrolytes. 41. An inorganic solid electrolyte membrane made from the inorganic superionic conductor material according to any one of claims 1 to 10 and 38. 42. The inorganic solid electrolyte membrane according to claim 41, wherein the inorganic solid electrolyte membrane has an ionic conductivity of 1× ^10-6-2 × ^10-2 S cm ^-1 , a tensile strength of 0.5-15 MPa, and maintains its original morphology after ignition for 500 s. 43. A lithium battery comprising the inorganic solid electrolyte membrane according to claim 41 or 42.