阅读说明：本技术 一种P、N掺杂多孔碳纤维-TiO2的锂离子电池负极材料的制法 (P, N doped porous carbon fiber-TiO2Preparation method of lithium ion battery cathode material ) 是由 夏新良 于 2020-11-30 设计创作，主要内容包括：本发明涉及锂离子电池技术领域,且公开了一种P、N掺杂多孔碳纤维-TiO_2的锂离子电池负极材料,二氯磷酸苯酯发生取代反应,得到丙烯酸羟丙基磷酸酯衍生物,与丙烯腈共聚,得到含氮磷聚丙烯腈共聚物,通过静电纺丝、预氧化、碳化,得到P、N掺杂多孔碳纤维包覆花状纳米二氧化钛,提高可逆比容量、倍率性能、导电性,抑制二氧化钛体积膨胀,花状纳米二氧化钛具有超高的比表面积,增大与电解液的接触面积,加速锂离子扩散,N原子具有一对孤对电子,作为给电子体,增强多孔碳纤维的导电性,P原子半径较大,引起结构缺陷,增大比表面积,使得锂离子电池负极材料具有优异的导电性、比容量、倍率性能和循环稳定性。(The invention relates to the technical field of lithium ion batteries, and discloses P, N doped porous carbon fiber-TiO 2 According to the lithium ion battery negative electrode material, phenyl dichlorophosphate is subjected to substitution reaction to obtain acrylic acid hydroxypropyl phosphate derivatives, the acrylic acid hydroxypropyl phosphate derivatives are copolymerized with acrylonitrile to obtain nitrogen-phosphorus-containing polyacrylonitrile copolymers, and P, N doped porous carbon fiber-coated flower-shaped nano titanium dioxide is obtained through electrostatic spinning, pre-oxidation and carbonization, so that the reversible specific capacity, the rate capability and the conductivity are improved, the volume expansion of the titanium dioxide is inhibited, and the flower-shaped nano titanium dioxide has ultrahigh contentThe specific surface area is increased, the contact area with electrolyte is increased, the diffusion of lithium ions is accelerated, the N atom has a pair of lone pair electrons and is used as an electron donor to enhance the conductivity of the porous carbon fiber, the radius of the P atom is large to cause structural defects, and the specific surface area is increased, so that the lithium ion battery cathode material has excellent conductivity, specific capacity, rate capability and cycling stability.)

1. P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material is characterized in that: the P, N doped porous carbon fiber-TiO₂The preparation method of the lithium ion battery negative electrode material comprises the following steps:

(1) adding diethylenetriamine into isopropanol, fully stirring, adding diisopropoxy bis-acetylacetone titanium, wherein the mass ratio of the diethylenetriamine to the diisopropoxy bis-acetylacetone titanium is 2-3:100, uniformly stirring, transferring into a reaction kettle, placing into a hydrothermal device, reacting for 12-36h at the temperature of 180 ℃ and 220 ℃, washing, filtering and drying to obtain a flower-shaped nano titanium dioxide precursor;

(2) placing the flower-shaped nano titanium dioxide precursor in a tubular furnace, and carrying out a calcination process to obtain flower-shaped nano titanium dioxide;

(3) adding phenyl dichlorophosphate into tetrahydrofuran, placing the mixture in an ice-water bath, stirring uniformly, adding triethylamine, slowly dropwise adding a tetrahydrofuran solution of hydroxypropyl acrylate, stirring for reacting for 3-5h, slowly dropwise adding a tetrahydrofuran solution of ethanolamine, stirring for 3-5h, heating to room temperature, stirring for 6-12h, performing suction filtration and reduced pressure distillation to obtain the acrylic hydroxypropyl phosphate derivative with the molecular formula of C₁₆H₂₄NO₅P；

(4) Adding acrylonitrile, acrylic acid hydroxypropyl phosphate derivatives and azobisisobutyronitrile into N, N-dimethylformamide, reacting for 6-18h at 60-70 ℃ in a nitrogen atmosphere, adding N, N-dimethylformamide, stirring uniformly, precipitating in deionized water, filtering, washing and drying to obtain a polyacrylonitrile copolymer containing nitrogen and phosphorus;

(5) adding nitrogen-phosphorus-containing polyacrylonitrile copolymer, polyvinylpyrrolidone and flower-shaped nanometer titanium dioxide into N, N-dimethylformamide, ultrasonically dispersing uniformly, preparing a fiber membrane of the nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower by electrostatic spinning, wherein the flow rate of a spinning solution in the spinning process is 0.5-1mL/h, the receiving distance is 10-20cm, washing and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower precursor;

(6) placing the polyacrylonitrile copolymer containing nitrogen and phosphorus coated titanium dioxide nanoflower precursor in a tubular furnace, and carrying out pre-oxidation and carbonization processes to obtain P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material.

2. P, N doped porous carbon fiber-TiO according to claim 1₂The lithium ion battery cathode material is characterized in that: the medium-temperature heating device comprises a main body, wherein a heat preservation layer is fixedly connected to the outer side of the main body, a heating layer is movably connected to the inner side of the heat preservation layer, an inner cavity is fixedly connected to the middle of the main body, gear teeth are movably connected to the bottom of the inner cavity, an object placing table is movably connected to the bottom of the inner cavity, a fixing rod is movably connected to the right side of the object placing table, and a gear is movably connected to the outer side of.

3. P, N doped porous carbon fiber-TiO according to claim 1₂The lithium ion battery cathode material is characterized in that: the calcination process in the step (2) is calcination at 480-520 ℃ for 1-3 h.

4. P, N doped porous carbon fiber-TiO according to claim 1₂The lithium ion battery cathode material is characterized in that: the mass ratio of phenyl dichlorophosphate, triethylamine, hydroxypropyl acrylate and ethanolamine in the step (3) is 100:85-115:55-65: 26-32.

5. P, N doped porous carbon fiber-TiO according to claim 1₂The lithium ion battery cathode material is characterized in that: in the step (4), the mass ratio of the acrylonitrile to the acrylic acid hydroxypropyl phosphate derivative to the azobisisobutyronitrile is 100:15-30: 0.3-0.6.

6. P, N doped porous carbon fiber-TiO according to claim 1₂The lithium ion battery cathode material is characterized in that: the mass ratio of the nitrogen-phosphorus-containing polyacrylonitrile copolymer, the polyvinylpyrrolidone and the flower-shaped nano titanium dioxide in the step (5) is 6-15:0.6-1.5: 100.

7. P, N doped porous carbon fiber-TiO according to claim 1₂The lithium ion battery cathode material is characterized in that: the carbonization process in the step (6) is to heat up to 260-300 ℃ at the speed of 1-3 ℃/min in the argon atmosphere, pre-oxidize for 1-2h, heat up to 750-850 ℃ at the speed of 4-6 ℃/min, and carbonize for 1-3 h.

Technical Field

The invention relates to the technical field of lithium ion batteries, in particular to P, N doped porous carbon fiber-TiO₂The preparation method of the lithium ion battery cathode material.

Background

In order to alleviate the crisis caused by the shortage of energy, people turn attention to the development of new energy automobiles, and lithium ion batteries are used as power sources of the new energy automobiles, have the advantages of high energy density, long service life and the like, but the current commercialized lithium ion batteries are made of graphite, have low theoretical specific capacity and short service life and are not ideal cathode materials, so that a new high-performance cathode material needs to be developed.

The transition metal oxide has higher theoretical specific capacity, longer service life and higher safety, wherein the nano TiO₂The porous carbon fiber has the advantages of high electrochemical activity, strong oxidation capacity, good chemical stability, high theoretical specific capacity and the like, is a cathode material with good application prospect, but has poor conductivity, easy agglomeration and volume effect, and limits the application of the cathode material, the porous carbon fiber has ultrahigh specific surface area and excellent conductivity, the ultrahigh specific surface area shortens the diffusion path of lithium ions, and simultaneously heteroatom doping further improves the conductivity of the lithium ions, so that P, N doped porous carbon fiber-TiO is adopted₂In order to solve the above problems.

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides P, N doped porous carbon fiber-TiO₂The preparation method of the lithium ion battery cathode material solves the problem of nanometer TiO₂The negative electrode material has poor conductivity, easy agglomeration and poor cycle performance.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: p, N doped porous carbon fiber-TiO₂The P, N doped porous carbon fiber-TiO negative electrode material of the lithium ion battery₂The preparation method of the lithium ion battery negative electrode material comprises the following steps:

(1) adding isopropanol and diethylenetriamine into a reaction bottle, fully stirring, adding diisopropoxy titanium bisacetylacetonate, wherein the mass ratio of the diethylenetriamine to the diisopropoxy titanium bisacetylacetonate is 2-3:100, uniformly stirring, transferring into a reaction kettle, placing into a hydrothermal device, reacting for 12-36h at the temperature of 180 ℃ and 220 ℃, washing with deionized water and ethanol, centrifugally filtering and drying to obtain a flower-shaped nano titanium dioxide precursor;

(2) placing the flower-shaped nano titanium dioxide precursor in a tubular furnace, and carrying out a calcination process to obtain flower-shaped nano titanium dioxide;

(3) adding tetrahydrofuran and phenyl dichlorophosphate into a reaction bottle, placing the reaction bottle in an ice-water bath, stirring for 20-40min, adding triethylamine, slowly dropwise adding a tetrahydrofuran solution of hydroxypropyl acrylate, stirring for reacting for 3-5h, slowly dropwise adding a tetrahydrofuran solution of ethanolamine, stirring for 3-5h, heating to room temperature, stirring for 6-12h, performing suction filtration and reduced pressure distillation to obtain the hydroxypropyl acrylate phosphate derivative with the molecular formula of C₁₆H₂₄NO₅P has a structural formula of

(4) Adding N, N-dimethylformamide, acrylonitrile, acrylic acid hydroxypropyl phosphate derivatives and azobisisobutyronitrile into a reaction bottle, reacting for 6-18h at 60-70 ℃ in a nitrogen atmosphere, adding N, N-dimethylformamide, stirring uniformly, then placing in deionized water for precipitation, filtering, washing with deionized water, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer;

(5) adding N, N-dimethylformamide, a nitrogen-phosphorus-containing polyacrylonitrile copolymer, polyvinylpyrrolidone and flower-shaped nanometer titanium dioxide into a reaction bottle, ultrasonically dispersing uniformly, preparing a fiber membrane of the nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower by electrostatic spinning, washing with deionized water to remove the residual polyvinylpyrrolidone, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower precursor, wherein the flow rate of a spinning solution in the spinning process is 0.5-1mL/h, and the receiving distance is 10-20 cm;

(6) placing the polyacrylonitrile copolymer containing nitrogen and phosphorus coated titanium dioxide nanoflower precursor in a tubular furnace, and carrying out pre-oxidation and carbonization processes to obtain P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material.

Preferably, the hydrothermal device in step (1) includes the main part, the outside fixedly connected with heat preservation of main part, the inboard swing joint of heat preservation has the zone of heating, the middle fixedly connected with inner chamber of main part, the bottom swing joint of inner chamber has the teeth of a cogwheel, the bottom swing joint of inner chamber has puts the thing platform, the right side swing joint who puts the thing platform has the dead lever, the outside swing joint of dead lever has the gear.

Preferably, the calcination process in the step (2) is calcination at 480-520 ℃ for 1-3 h.

Preferably, the mass ratio of phenyl dichlorophosphate to triethylamine to hydroxypropyl acrylate to ethanolamine in the step (3) is 100:85-115:55-65: 26-32.

Preferably, the mass ratio of the acrylonitrile to the acrylic acid hydroxypropyl phosphate derivative to the azobisisobutyronitrile in the step (4) is 100:15-30: 0.3-0.6.

Preferably, the mass ratio of the nitrogen-phosphorus-containing polyacrylonitrile copolymer, the polyvinylpyrrolidone and the flower-like nano titanium dioxide in the step (5) is 6-15:0.6-1.5: 100.

Preferably, the carbonization process in the step (6) is to heat up to 260-300 ℃ at a rate of 1-3 ℃/min in an argon atmosphere, pre-oxidize for 1-2h, heat up to 750-850 ℃ at a rate of 4-6 ℃/min, and carbonize for 1-3 h.

(III) advantageous technical effects

Compared with the prior art, the invention has the following beneficial technical effects:

the P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material is prepared by calcining a flower-shaped nano titanium dioxide precursor obtained by stacking nano sheets to obtain flower-shaped nano titanium dioxide, in an ice-water bath, a phosphoryl chloride group on phenyl dichlorophosphate firstly undergoes a substitution reaction with hydroxypropyl acrylate to introduce an alkenyl group, then undergoes a substitution reaction with ethanolamine to introduce a nitrogen atom to obtain an acrylic acid hydroxypropyl phosphate derivative, and under the action of a catalyst azodiisobutyronitrile, the alkenyl group is copolymerized with the alkenyl group of acrylonitrile to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer, so that the flower-shaped nano titanium dioxide is obtainedNitrogen atoms and phosphorus atoms are uniformly distributed, a nitrogen-phosphorus-containing polyacrylonitrile copolymer-coated titanium dioxide nanoflower precursor is obtained through electrostatic spinning, flower-shaped nano titanium dioxide is uniformly distributed on the copolymer, and N atoms and P atoms are uniformly distributed on porous carbon fibers through pre-oxidation and carbonization to obtain P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material.

The P, N doped porous carbon fiber-TiO₂The flower-shaped nano titanium dioxide has ultrahigh specific surface area, is beneficial to exposing more electrochemical active sites, simultaneously increases the contact area with electrolyte, accelerates the diffusion of lithium ions, the N atom is doped into the crystal lattice of the porous carbon fiber, has a pair of lone pair electrons and is used as an electron donor to enhance the conductivity of the porous carbon fiber, the P atom doped into the crystal lattice of the porous carbon fiber has larger atomic radius to cause the structural defect of the porous carbon fiber, forms a three-dimensional porous structure, increases the specific surface area, accelerates the escape of surface electrons, further enhances the conductivity of the porous carbon fiber, the flower-shaped nano titanium dioxide is uniformly distributed on a copolymer, and is preoxidized and carbonized to form P, N doped porous carbon fiber coated flower-shaped nano titanium dioxide to promote the embedding and the releasing of the lithium ions, the reversible specific capacity is improved, so that the rate capability is improved, meanwhile, the porous carbon fiber provides a certain space for the volume expansion of the titanium dioxide, the volume expansion of the titanium dioxide is inhibited to a certain extent, the stability of the cathode material is improved, meanwhile, P, N is doped with the coating of the porous carbon fiber, the charge transfer impedance of the titanium dioxide is reduced, the conductivity is improved, and P, N is doped with the porous carbon fiber-TiO₂The lithium ion battery cathode material has excellent conductivity, specific capacity, rate capability and cycling stability.

Drawings

FIG. 1 is a schematic structural view of a hydrothermal device in front view;

FIG. 2 is a schematic side view of a hydrothermal apparatus;

fig. 3 is a schematic view of a gear structure.

1. A main body; 2. a heat-insulating layer; 3. a heating layer; 4. an inner cavity; 5. gear teeth; 6. a placing table; 7. fixing the rod; 8. a gear.

Detailed Description

To achieve the above object, the present invention provides the following embodiments and examples: p, N doped porous carbon fiber-TiO₂P, N doped porous carbon fiber-TiO lithium ion battery cathode material₂The preparation method of the lithium ion battery negative electrode material comprises the following steps:

(1) adding isopropanol and diethylenetriamine into a reaction bottle, fully stirring, adding diisopropoxy titanium bisacetylacetonate, wherein the mass ratio of diethylenetriamine to diisopropoxy titanium bisacetylacetonate is 2-3:100, uniformly stirring, moving the mixture into a reaction kettle, placing the reaction kettle into a hydrothermal device, wherein the hydrothermal device comprises a main body, the outer side of the main body is fixedly connected with a heat preservation layer, the inner side of the heat preservation layer is movably connected with a heating layer, the middle of the main body is fixedly connected with an inner cavity, the bottom of the inner cavity is movably connected with gear teeth, the bottom of the inner cavity is movably connected with a placing table, the right side of the placing table is movably connected with a fixed rod, the outer side of the fixed rod is movably connected with a gear, reacting for 12-36 hours at 180 ℃ and 220 ℃, washing with deionized water and ethanol;

(2) placing the flower-shaped nano titanium dioxide precursor in a tubular furnace, and performing a calcination process, wherein the calcination process is to calcine at 480-520 ℃ for 1-3h to obtain the flower-shaped nano titanium dioxide;

(3) adding tetrahydrofuran and phenyl dichlorophosphate into a reaction bottle, placing the reaction bottle in an ice-water bath, stirring for 20-40min, adding triethylamine, slowly dropwise adding a tetrahydrofuran solution of hydroxypropyl acrylate, stirring for reacting for 3-5h, and slowly dropwise adding a tetrahydrofuran solution of ethanolamine, wherein the mass ratio of the phenyl dichlorophosphate to the triethylamine to the hydroxypropyl acrylate to the ethanolamine is 100:85-115:55-65:26-32, stirring for 3-5h, heating to room temperature, stirring for 6-12h, performing suction filtration and reduced pressure distillation to obtain the hydroxypropyl acrylate derivative with the molecular formula of C₁₆H₂₄NO₅P has a structural formula of

(4) Adding N, N-dimethylformamide, acrylonitrile, acrylic acid hydroxypropyl phosphate derivatives and azobisisobutyronitrile into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the acrylonitrile to the acrylic acid hydroxypropyl phosphate derivatives to the azobisisobutyronitrile is 100:15-30:0.3-0.6, reacting for 6-18h at 60-70 ℃ in a nitrogen atmosphere, adding the N, N-dimethylformamide, stirring uniformly, precipitating in deionized water, filtering, washing with the deionized water, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer;

(5) adding N, N-dimethylformamide, a nitrogen-phosphorus-containing polyacrylonitrile copolymer, polyvinylpyrrolidone and flower-shaped nanometer titanium dioxide into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the nitrogen-phosphorus-containing polyacrylonitrile copolymer to the polyvinylpyrrolidone to the flower-shaped nanometer titanium dioxide is 6-15:0.6-1.5:100, performing ultrasonic dispersion uniformly, preparing a fiber membrane of the nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower by electrostatic spinning, washing with deionized water to remove the residual polyvinylpyrrolidone, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower precursor, wherein the flow rate of a spinning solution in the spinning process is 0.5-1mL/h, and the receiving distance is 10-20 cm;

(6) placing the polyacrylonitrile copolymer containing nitrogen and phosphorus coated titanium dioxide nanoflower precursor in a tubular furnace, and carrying out preoxidation and carbonization processes, wherein the carbonization process comprises the steps of heating to 260-300 ℃ at the speed of 1-3 ℃/min in the argon atmosphere, carrying out preoxidation for 1-2h, heating to 750-850 ℃ at the speed of 4-6 ℃/min, and carbonizing for 1-3h to obtain P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material.

Example 1

(1) Adding isopropanol and diethylenetriamine into a reaction bottle, fully stirring, adding diisopropoxy bis-acetylacetone titanium, wherein the mass ratio of diethylenetriamine to diisopropoxy bis-acetylacetone titanium is 2:100, uniformly stirring, moving into a reaction kettle, placing into a hydrothermal device, wherein the hydrothermal device comprises a main body, the outer side of the main body is fixedly connected with a heat preservation layer, the inner side of the heat preservation layer is movably connected with a heating layer, the middle of the main body is fixedly connected with an inner cavity, the bottom of the inner cavity is movably connected with gear teeth, the bottom of the inner cavity is movably connected with a placing table, the right side of the placing table is movably connected with a fixed rod, the outer side of the fixed rod is movably connected with a gear, reacting for 12 hours at 180 ℃, washing with deionized water and ethanol, centrifuging, filtering and;

(2) placing the flower-shaped nano titanium dioxide precursor in a tubular furnace, and performing a calcination process, wherein the calcination process is to calcine at 480 ℃ for 1h to obtain flower-shaped nano titanium dioxide;

(3) adding tetrahydrofuran and phenyl dichlorophosphate into a reaction bottle, placing the reaction bottle in an ice-water bath, stirring for 20min, adding triethylamine, slowly dropwise adding a tetrahydrofuran solution of hydroxypropyl acrylate, stirring for reaction for 3h, and slowly dropwise adding a tetrahydrofuran solution of ethanolamine, wherein the mass ratio of the phenyl dichlorophosphate to the triethylamine to the hydroxypropyl acrylate to the ethanolamine is 100:85:55:26, stirring for 3h, heating to room temperature, stirring for 6h, filtering, and distilling under reduced pressure to obtain the hydroxypropyl acrylate phosphate derivative with the molecular formula of C₁₆H₂₄NO₅P has a structural formula of

(4) Adding N, N-dimethylformamide, acrylonitrile, acrylic acid hydroxypropyl phosphate derivatives and azodiisobutyronitrile into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the acrylonitrile to the acrylic acid hydroxypropyl phosphate derivatives to the azodiisobutyronitrile is 100:15:0.3, reacting at 60 ℃ for 6 hours in a nitrogen atmosphere, adding the N, N-dimethylformamide, stirring uniformly, then placing in deionized water for precipitation, filtering, washing with the deionized water, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer;

(5) adding N, N-dimethylformamide, a nitrogen-phosphorus-containing polyacrylonitrile copolymer, polyvinylpyrrolidone and flower-shaped nanometer titanium dioxide into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the nitrogen-phosphorus-containing polyacrylonitrile copolymer to the polyvinylpyrrolidone to the flower-shaped nanometer titanium dioxide is 6:0.6:100, performing ultrasonic dispersion uniformly, preparing a fiber membrane of the nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower by electrostatic spinning, washing with deionized water to remove the residual polyvinylpyrrolidone, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower precursor, wherein the flow rate of a spinning solution in the spinning process is 0.5mL/h, and the receiving distance is 10 cm;

(6) putting the polyacrylonitrile copolymer containing nitrogen and phosphorus coated titanium dioxide nanoflower precursor into a tubular furnace, and carrying out pre-oxidation and carbonizationThe process comprises the steps of firstly heating to 260 ℃ at the speed of 1 ℃/min in the argon atmosphere, pre-oxidizing for 1h, then heating to 750 ℃ at the speed of 4 ℃/min, and carbonizing for 1h to obtain P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material.

Example 2

(1) Adding isopropanol and diethylenetriamine into a reaction bottle, fully stirring, adding diisopropoxy bis-acetylacetone titanium, wherein the mass ratio of diethylenetriamine to diisopropoxy bis-acetylacetone titanium is 2.5:100, uniformly stirring, moving the mixture into a reaction kettle, placing the mixture into a hydrothermal device, wherein the hydrothermal device comprises a main body, the outer side of the main body is fixedly connected with a heat preservation layer, the inner side of the heat preservation layer is movably connected with a heating layer, the middle of the main body is fixedly connected with an inner cavity, the bottom of the inner cavity is movably connected with gear teeth, the bottom of the inner cavity is movably connected with a placing table, the right side of the placing table is movably connected with a fixed rod, the outer side of the fixed rod is movably connected with a gear, reacting for 24 hours at 200 ℃, washing with deionized water and ethanol;

(2) placing the flower-shaped nano titanium dioxide precursor in a tubular furnace, and carrying out a calcination process, wherein the calcination process is to calcine at 500 ℃ for 2 hours to obtain flower-shaped nano titanium dioxide;

(3) adding tetrahydrofuran and phenyl dichlorophosphate into a reaction bottle, placing the reaction bottle in an ice-water bath, stirring for 30min, adding triethylamine, slowly dropwise adding a tetrahydrofuran solution of hydroxypropyl acrylate, stirring for reaction for 4h, and slowly dropwise adding a tetrahydrofuran solution of ethanolamine, wherein the mass ratio of the phenyl dichlorophosphate to the triethylamine to the hydroxypropyl acrylate to the ethanolamine is 100:100:60:29, stirring for 4h, heating to room temperature, stirring for 9h, filtering, and distilling under reduced pressure to obtain the hydroxypropyl acrylate phosphate derivative with the molecular formula of C₁₆H₂₄NO₅P has a structural formula of

(4) Adding N, N-dimethylformamide, acrylonitrile, acrylic acid hydroxypropyl phosphate derivative and azobisisobutyronitrile into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the acrylonitrile to the acrylic acid hydroxypropyl phosphate derivative to the azobisisobutyronitrile is 100:22.5:0.5, reacting at 65 ℃ for 12 hours in a nitrogen atmosphere, adding the N, N-dimethylformamide, stirring uniformly, precipitating in deionized water, filtering, washing with the deionized water, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer;

(5) adding N, N-dimethylformamide, a nitrogen-phosphorus-containing polyacrylonitrile copolymer, polyvinylpyrrolidone and flower-shaped nano titanium dioxide into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the nitrogen-phosphorus-containing polyacrylonitrile copolymer to the polyvinylpyrrolidone to the flower-shaped nano titanium dioxide is 10.5:1.1:100, performing ultrasonic dispersion uniformly, preparing a fiber membrane of the nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanoflowers through electrostatic spinning, wherein the flow rate of a spinning solution in the spinning process is 0.8mL/h, the receiving distance is 15cm, washing with deionized water to remove the residual polyvinylpyrrolidone, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanoflower precursor;

(6) placing the nitrogen-phosphorus-containing polyacrylonitrile copolymer-coated titanium dioxide nanoflower precursor in a tubular furnace, and carrying out preoxidation and carbonization processes, wherein the carbonization process comprises the steps of firstly heating to 280 ℃ at the speed of 2 ℃/min in the argon atmosphere, carrying out preoxidation for 1.5h, then heating to 800 ℃ at the speed of 5 ℃/min, and carbonizing for 2h to obtain P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material.

Example 3

(1) Adding isopropanol and diethylenetriamine into a reaction bottle, fully stirring, adding diisopropoxy bis-acetylacetone titanium, wherein the mass ratio of diethylenetriamine to diisopropoxy bis-acetylacetone titanium is 2.3:100, uniformly stirring, moving the mixture into a reaction kettle, placing the mixture into a hydrothermal device, wherein the hydrothermal device comprises a main body, the outer side of the main body is fixedly connected with a heat preservation layer, the inner side of the heat preservation layer is movably connected with a heating layer, the middle of the main body is fixedly connected with an inner cavity, the bottom of the inner cavity is movably connected with gear teeth, the bottom of the inner cavity is movably connected with a placing table, the right side of the placing table is movably connected with a fixed rod, the outer side of the fixed rod is movably connected with a gear, reacting for 18 hours at 210 ℃, washing with deionized water and ethanol;

(2) placing the flower-shaped nano titanium dioxide precursor in a tubular furnace, and carrying out a calcination process, wherein the calcination process is carried out for 2 hours at 490 ℃ to obtain flower-shaped nano titanium dioxide;

(3) adding tetrahydrofuran and phenyl dichlorophosphate into a reaction bottle, placing the reaction bottle in an ice-water bath, stirring for 25min, adding triethylamine, slowly dropwise adding a tetrahydrofuran solution of hydroxypropyl acrylate, stirring for reacting for 3.5h, and slowly dropwise adding a tetrahydrofuran solution of ethanolamine, wherein the mass ratio of the phenyl dichlorophosphate to the triethylamine to the hydroxypropyl acrylate to the ethanolamine is 100:95:58:28, stirring for 3.5h, heating to room temperature, stirring for 8h, performing suction filtration, and performing reduced pressure distillation to obtain the hydroxypropyl acrylate phosphate derivative with the molecular formula C₁₆H₂₄NO₅P has a structural formula of

(4) Adding N, N-dimethylformamide, acrylonitrile, acrylic acid hydroxypropyl phosphate derivative and azodiisobutyronitrile into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the acrylonitrile to the acrylic acid hydroxypropyl phosphate derivative to the azodiisobutyronitrile is 100:20:0.4, reacting at 65 ℃ for 10 hours in a nitrogen atmosphere, adding the N, N-dimethylformamide, stirring uniformly, then placing in deionized water for precipitation, filtering, washing with the deionized water, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer;

(5) adding N, N-dimethylformamide, a nitrogen-phosphorus-containing polyacrylonitrile copolymer, polyvinylpyrrolidone and flower-shaped nanometer titanium dioxide into a reaction bottle, wherein the mass ratio of N, N-dimethylformamide to nitrogen-phosphorus-containing polyacrylonitrile copolymer to polyvinylpyrrolidone to flower-shaped nanometer titanium dioxide is 10:1:100, ultrasonically dispersing uniformly, preparing a fiber membrane of the nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower by electrostatic spinning, washing with deionized water to remove the residual polyvinylpyrrolidone, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower precursor, wherein the flow rate of a spinning solution in the spinning process is 0.7mL/h and the receiving distance is 13 cm;

(6) placing the nitrogen-phosphorus-containing polyacrylonitrile copolymer-coated titanium dioxide nanoflower precursor in a tubular furnace, and carrying out preoxidation and carbonization processes, wherein the carbonization process comprises the steps of firstly heating to 270 ℃ at the speed of 2 ℃/min in the argon atmosphere, carrying out preoxidation for 1h, then heating to 790 ℃ at the speed of 5 ℃/min, and carbonizing for 3h to obtain P, N doped porous carbon fiber-TiO₂Lithium ion ofAnd (4) a sub-battery negative electrode material.

Example 4

(1) Adding isopropanol and diethylenetriamine into a reaction bottle, fully stirring, adding diisopropoxy bis-acetylacetone titanium, wherein the mass ratio of diethylenetriamine to diisopropoxy bis-acetylacetone titanium is 3:100, uniformly stirring, moving into a reaction kettle, placing into a hydrothermal device, wherein the hydrothermal device comprises a main body, the outer side of the main body is fixedly connected with a heat preservation layer, the inner side of the heat preservation layer is movably connected with a heating layer, the middle of the main body is fixedly connected with an inner cavity, the bottom of the inner cavity is movably connected with gear teeth, the bottom of the inner cavity is movably connected with a placing table, the right side of the placing table is movably connected with a fixed rod, the outer side of the fixed rod is movably connected with a gear, reacting for 36 hours at 220 ℃, washing with deionized water and ethanol, centrifuging, filtering and;

(2) placing the flower-shaped nano titanium dioxide precursor in a tube furnace, and calcining for 3 hours at 520 ℃ to obtain flower-shaped nano titanium dioxide;

(3) adding tetrahydrofuran and phenyl dichlorophosphate into a reaction bottle, placing the reaction bottle in an ice-water bath, stirring for 40min, adding triethylamine, slowly dropwise adding a tetrahydrofuran solution of hydroxypropyl acrylate, stirring for reaction for 5h, and slowly dropwise adding a tetrahydrofuran solution of ethanolamine, wherein the mass ratio of the phenyl dichlorophosphate to the triethylamine to the hydroxypropyl acrylate to the ethanolamine is 100:115:65:32, stirring for 5h, heating to room temperature, stirring for 12h, filtering, and distilling under reduced pressure to obtain the hydroxypropyl acrylate phosphate derivative with the molecular formula of C₁₆H₂₄NO₅P has a structural formula of

(4) Adding N, N-dimethylformamide, acrylonitrile, acrylic acid hydroxypropyl phosphate derivative and azodiisobutyronitrile into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the acrylonitrile to the acrylic acid hydroxypropyl phosphate derivative to the azodiisobutyronitrile is 100:30:0.6, reacting at 70 ℃ for 18 hours in a nitrogen atmosphere, adding the N, N-dimethylformamide, stirring uniformly, precipitating in deionized water, filtering, washing with the deionized water, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer;

(5) adding N, N-dimethylformamide, a nitrogen-phosphorus-containing polyacrylonitrile copolymer, polyvinylpyrrolidone and flower-shaped nanometer titanium dioxide into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the nitrogen-phosphorus-containing polyacrylonitrile copolymer to the polyvinylpyrrolidone to the flower-shaped nanometer titanium dioxide is 15:1.5:100, ultrasonically dispersing uniformly, preparing a fiber membrane of the nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower by electrostatic spinning, washing with deionized water to remove the residual polyvinylpyrrolidone, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanometer flower precursor;

(6) placing the nitrogen-phosphorus-containing polyacrylonitrile copolymer-coated titanium dioxide nanoflower precursor in a tubular furnace, and carrying out preoxidation and carbonization processes, wherein the carbonization process comprises the steps of firstly heating to 300 ℃ at the speed of 3 ℃/min in the argon atmosphere, carrying out preoxidation for 2h, then heating to 850 ℃ at the speed of 6 ℃/min, and carbonizing for 3h to obtain P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material.

Comparative example 1

(1) Adding isopropanol and diethylenetriamine into a reaction bottle, fully stirring, adding diisopropoxy bis-acetylacetone titanium, wherein the mass ratio of diethylenetriamine to diisopropoxy bis-acetylacetone titanium is 1:100, uniformly stirring, moving into a reaction kettle, placing into a hydrothermal device, wherein the hydrothermal device comprises a main body, the outer side of the main body is fixedly connected with a heat preservation layer, the inner side of the heat preservation layer is movably connected with a heating layer, the middle of the main body is fixedly connected with an inner cavity, the bottom of the inner cavity is movably connected with gear teeth, the bottom of the inner cavity is movably connected with a placing table, the right side of the placing table is movably connected with a fixed rod, the outer side of the fixed rod is movably connected with a gear, reacting for 24 hours at 200 ℃, washing with deionized water and ethanol, centrifuging, filtering and;

(2) placing the flower-shaped nano titanium dioxide precursor in a tube furnace, and calcining for 3 hours at 490 ℃ to obtain flower-shaped nano titanium dioxide;

(3) adding tetrahydrofuran and phenyl dichlorophosphate into a reaction bottle, placing the reaction bottle in an ice-water bath, stirring for 20min, and adding triethylamineSlowly dripping a tetrahydrofuran solution of hydroxypropyl acrylate, stirring for reaction for 5 hours, slowly dripping a tetrahydrofuran solution of ethanolamine, wherein the mass ratio of phenyl dichlorophosphate to triethylamine to hydroxypropyl acrylate to ethanolamine is 100:80:50:20, stirring for 5 hours, heating to room temperature, stirring for 8 hours, performing suction filtration and reduced pressure distillation to obtain the hydroxypropyl acrylate phosphate derivative with the molecular formula of C₁₆H₂₄NO₅P has a structural formula of

(4) Adding N, N-dimethylformamide, acrylonitrile, acrylic acid hydroxypropyl phosphate derivatives and azodiisobutyronitrile into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the acrylonitrile to the acrylic acid hydroxypropyl phosphate derivatives to the azodiisobutyronitrile is 100:10:0.1, reacting at 60 ℃ for 12 hours in a nitrogen atmosphere, adding the N, N-dimethylformamide, stirring uniformly, then placing in deionized water for precipitation, filtering, washing with the deionized water, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer;

(5) adding N, N-dimethylformamide, a nitrogen-phosphorus-containing polyacrylonitrile copolymer, polyvinylpyrrolidone and flower-shaped nano titanium dioxide into a reaction bottle, wherein the mass ratio of the N, N-dimethylformamide to the nitrogen-phosphorus-containing polyacrylonitrile copolymer to the polyvinylpyrrolidone to the flower-shaped nano titanium dioxide is 5:0.5:100, ultrasonically dispersing uniformly, preparing a fiber membrane of the nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanoflowers through electrostatic spinning, washing with deionized water to remove the residual polyvinylpyrrolidone, and drying to obtain a nitrogen-phosphorus-containing polyacrylonitrile copolymer coated titanium dioxide nanoflower precursor, wherein the flow rate of a spinning solution in the spinning process is 0.7mL/h, and the receiving distance is 15 cm;

(6) placing the nitrogen-phosphorus-containing polyacrylonitrile copolymer-coated titanium dioxide nanoflower precursor in a tubular furnace, and carrying out preoxidation and carbonization processes, wherein the carbonization process comprises the steps of firstly heating to 260 ℃ at the speed of 2 ℃/min in the argon atmosphere, carrying out preoxidation for 2h, then heating to 790 ℃ at the speed of 4 ℃/min, and carrying out carbonization for 2h to obtain P, N doped porous carbon fiber-TiO₂The lithium ion battery cathode material.

P, N-doped porous carbon fiber-TiO obtained in example and comparative example were added to N-methylpyrrolidone at a mass ratio of 8:1:1₂Lithium ion battery negative electrode materialMixing the materials, acetylene black and polyvinylidene fluoride into uniform coating, uniformly coating the coating on a copper foil by a coating method, drying, punching into a circular electrode plate with the diameter of 10mm as a working electrode, a lithium plate as a counter electrode, a porous polypropylene film as a diaphragm and 1mol/L electrolyte of LiPF₆The solution is assembled into a button cell in a glove box, the assembled cell is subjected to constant-current charge-discharge test on a BT-100V20C40F type cell test system, and the discharge specific capacity of the cell is tested, wherein the test standard is GB/T36276 plus 2018.