阅读说明：本技术 一种无机非金属复合材料的制备方法及储能应用 (Preparation method and energy storage application of inorganic non-metal composite material ) 是由 李埃荣 王新龙 小泽康典 李伟力 徐永纪 于 2020-12-11 设计创作，主要内容包括：本发明涉及一种无机非金属复合材料的制备方法及储能应用,其中制备方法包括以下步骤：步骤1,制备碲化锶纳米材料：使用氯化锶与亚碲酸钠在氮川三乙酸的作用下进行反应,制备得到碲化锶纳米材料；步骤2,制备改性碲化锶纳米材料：使用碘酸钾与所述碲化锶纳米材料在酸性条件下进行反应,制备得到改性碲化锶纳米材料；步骤3,制备无机非金属复合材料：使用纳米石墨烯与所述改性碲化锶纳米材料掺杂混合,得到无机非金属复合材料。本发明制备得到的无机非金属复合材料能够替代石墨作为现有的锂离子电池中的负极材料,该无机非金属复合材料相比较于石墨具有更好的充放电倍率,更优异的低温性能,以及与电解质也能有较好的相容性。(The invention relates to a preparation method and energy storage application of an inorganic non-metallic composite material, wherein the preparation method comprises the following steps: step 1, preparing a strontium telluride nano material: reacting strontium chloride and sodium tellurite under the action of nitrilotriacetic acid to prepare a strontium telluride nano material; step 2, preparing the modified strontium telluride nano material: reacting potassium iodate with the strontium telluride nano material under an acidic condition to prepare a modified strontium telluride nano material; step 3, preparing the inorganic non-metallic composite material: and doping and mixing nano graphene and the modified strontium telluride nano material to obtain the inorganic non-metallic composite material. The inorganic non-metallic composite material prepared by the invention can replace graphite to be used as a cathode material in the existing lithium ion battery, and compared with graphite, the inorganic non-metallic composite material has better charge-discharge multiplying power, more excellent low-temperature performance and better compatibility with electrolyte.)

1. The preparation method of the inorganic non-metal composite material is characterized by comprising the following steps:

step 1, preparing a strontium telluride nano material:

reacting strontium chloride and sodium tellurite under the action of nitrilotriacetic acid to prepare a strontium telluride nano material;

step 2, preparing the modified strontium telluride nano material:

reacting potassium iodate with the strontium telluride nano material under an acidic condition to prepare a modified strontium telluride nano material;

step 3, preparing the inorganic non-metallic composite material:

and doping and mixing nano graphene and the modified strontium telluride nano material to obtain the inorganic non-metallic composite material.

2. The method for preparing the inorganic non-metallic composite material according to claim 1, wherein the grain size of the strontium telluride nano material is 100-200 nm; the particle size of the modified strontium telluride nano material is 150-250 nm.

3. The method of claim 1, wherein the acidic condition in step 2 is a pH of 3.0 to 5.0.

4. The method as claimed in claim 1, wherein the mixing step in step 3 comprises wet grinding, spray drying and heat treatment.

5. The method for preparing the inorganic non-metallic composite material according to claim 1, wherein the step 1 specifically comprises:

s1, weighing strontium chloride, adding the strontium chloride into ammonia water, and completely dissolving to obtain a strontium chloride solution; weighing sodium tellurite, adding the sodium tellurite into deionized water, and stirring until the sodium tellurite is completely dissolved to obtain a sodium tellurite solution;

wherein the mass fraction of the ammonia water is 20-30%, the mass ratio of the strontium chloride to the ammonia water is 1: 5-10, and the mass ratio of the sodium tellurite to the deionized water is 1: 10-20;

s2, slowly adding the sodium tellurite solution into the strontium chloride solution, stirring uniformly, then dropwise adding nitrilotriacetic acid while stirring, after dropwise adding, continuously stirring for 0.5-1 h, then pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in an oven with the temperature of 140-160 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the oven with the temperature of 80-100 ℃ for drying, and crushing into nanoparticles to obtain the strontium telluride nano material;

wherein the mass ratio of the strontium chloride solution, the sodium tellurite solution and the nitrilotriacetic acid is 1: 2.5-3.5: 0.1-0.3.

6. The method for preparing the inorganic non-metallic composite material according to claim 1, wherein the step 2 specifically comprises:

s1, weighing the potassium iodate, adding the potassium iodate into deionized water, stirring until the potassium iodate is completely dissolved, adding the strontium telluride nano material, and performing ultrasonic dispersion until the strontium telluride nano material is uniformly dispersed to obtain a strontium telluride/potassium iodate mixed solution;

wherein the mass ratio of the potassium iodate to the strontium telluride nano material to the deionized water is 1: 3.2-4.5: 12-18;

s2, adding acid to adjust the pH value of the strontium telluride/potassium iodate mixed solution to 3.0-5.0, heating to 60-80 ℃, stirring for 0.5-2 h, pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in a drying oven with the temperature of 150-170 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the drying oven with the temperature of 80-100 ℃ for drying, and transferring into a nano crusher for crushing into nano particles to obtain the modified strontium telluride nano material.

7. The method of claim 6, wherein the acid is nitric acid or hydrochloric acid during the acid addition adjustment in the step 2.

8. The method for preparing the inorganic non-metallic composite material according to claim 1, wherein the step 3 specifically comprises:

s1: adding the modified strontium telluride nano material into N-methyl pyrrolidone, stirring uniformly, adding nano graphene, and pouring into a ball mill for ball milling to obtain graphene/modified strontium telluride mixed feed liquid;

the mass ratio of the modified strontium telluride nano material to the nano graphene to the N-methyl pyrrolidone is 1: 4.5-6.5: 10-15; the ball milling time is 2-4 h, and the ball milling revolution is 200-500 rpm;

s2, adding the graphene/modified strontium telluride mixed material liquid into a nano high-pressure homogenizer for dispersion treatment, and then transferring into a centrifugal spray drying tower for spray drying treatment to obtain graphene/modified strontium telluride mixed powder;

wherein the pressure of the high-pressure homogenizer is 50-100 MPa, the dispersion treatment time is 1-2 h, and the spray drying pressure is 10-20 MPa;

s3, adding the graphene/modified strontium telluride mixed powder into a crucible, then placing the crucible into a graphite furnace, carrying out heat treatment under the protection of inert gas, and cooling the crucible to room temperature to obtain an inorganic non-metal composite material;

wherein the temperature of the heat treatment is 220-300 ℃; the heat treatment time is 2-5 h.

9. The method for preparing the inorganic non-metallic composite material according to claim 8, wherein the water content of the graphene/modified strontium telluride mixed powder is less than or equal to 0.2%.

10. An energy storage application of an inorganic non-metallic composite material is characterized in that: the inorganic non-metallic composite material is prepared by the preparation method of the inorganic non-metallic composite material according to any one of claims 1 to 9, and is applied to electrochemical energy storage.

Technical Field

The invention relates to the field of inorganic non-metal composite materials, in particular to a preparation method and energy storage application of an inorganic non-metal composite material.

Background

With the continuous development of science and technology and the continuous improvement of the living standard of people, the demands of people on products such as multifunctional portable electronic equipment, electric automobiles and the like are increasing day by day. However, the problem of energy shortage in the current society is becoming more serious, the contradiction that the energy supply and demand are not matched in time and space is gradually excited, meanwhile, the global warming and the ecological environment are continuously deteriorated due to the large consumption of fossil fuels, and the energy conservation and the development of renewable energy become hot spots which are currently concerned by people, so the research and development of clean energy promotes the development of energy storage materials and devices. The lithium ion battery as an energy storage material has the advantages of high energy density, good load characteristics, fast charge and discharge, high safety performance, long cycle life and low cost, and has become the most important research direction.

However, most of the lithium ion batteries commercialized at present use graphite as a negative electrode, the theoretical specific capacity of the graphite as a negative electrode material is only 372mAh/g, and the defects of poor charge-discharge rate performance, poor compatibility with electrolyte, poor low-temperature performance and the like exist, and the development process of the lithium ion batteries in the fields of power and energy storage batteries is directly influenced.

Disclosure of Invention

Aiming at the problems, the invention provides a preparation method and an energy storage application of an inorganic non-metal composite material, which solve the defects of poor charge-discharge rate performance, poor compatibility with electrolyte, poor low-temperature performance and the like of the conventional lithium ion battery cathode material.

The purpose of the invention is realized by adopting the following technical scheme:

in a first aspect, the present invention provides a method for preparing an inorganic non-metallic composite material, comprising the steps of:

step 1, preparing a strontium telluride nano material:

reacting strontium chloride and sodium tellurite under the action of nitrilotriacetic acid to prepare a strontium telluride nano material;

step 2, preparing the modified strontium telluride nano material:

reacting potassium iodate with the strontium telluride nano material under an acidic condition to prepare a modified strontium telluride nano material;

step 3, preparing the inorganic non-metallic composite material:

and doping and mixing nano graphene and the modified strontium telluride nano material to obtain the inorganic non-metallic composite material.

Preferably, the grain size of the strontium telluride nano material is 100-200 nm; the particle size of the modified strontium telluride nano material is 150-250 nm.

Preferably, the acidic condition in the step 2 is pH 3.0-5.0.

Preferably, the doping and mixing process in step 3 is wet grinding, spray drying and heat treatment in sequence.

Preferably, the step 1 specifically comprises:

s1, weighing strontium chloride, adding the strontium chloride into ammonia water, and completely dissolving to obtain a strontium chloride solution; weighing sodium tellurite, adding the sodium tellurite into deionized water, and stirring until the sodium tellurite is completely dissolved to obtain a sodium tellurite solution;

wherein the mass fraction of the ammonia water is 20-30%, the mass ratio of the strontium chloride to the ammonia water is 1: 5-10, and the mass ratio of the sodium tellurite to the deionized water is 1: 10-20;

s2, slowly adding the sodium tellurite solution into the strontium chloride solution, stirring uniformly, then dropwise adding nitrilotriacetic acid while stirring, after dropwise adding, continuously stirring for 0.5-1 h, then pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in an oven with the temperature of 140-160 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the oven with the temperature of 80-100 ℃ for drying, and crushing into nanoparticles to obtain the strontium telluride nano material;

wherein the mass ratio of the strontium chloride solution, the sodium tellurite solution and the nitrilotriacetic acid is 1: 2.5-3.5: 0.1-0.3.

Preferably, the step 2 specifically comprises:

s1, weighing the potassium iodate, adding the potassium iodate into deionized water, stirring until the potassium iodate is completely dissolved, adding the strontium telluride nano material, and performing ultrasonic dispersion until the strontium telluride nano material is uniformly dispersed to obtain a strontium telluride/potassium iodate mixed solution;

wherein the mass ratio of the potassium iodate to the strontium telluride nano material to the deionized water is 1: 3.2-4.5: 12-18;

s2, adding acid to adjust the pH value of the strontium telluride/potassium iodate mixed solution to 3.0-5.0, heating to 60-80 ℃, stirring for 0.5-2 h, pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in a drying oven with the temperature of 150-170 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the drying oven with the temperature of 80-100 ℃ for drying, and transferring into a nano crusher for crushing into nano particles to obtain the modified strontium telluride nano material.

Preferably, in the step 2, during the adjustment process by adding acid, the acid added is nitric acid or hydrochloric acid.

Preferably, the step 3 specifically comprises:

s1: adding the modified strontium telluride nano material into N-methyl pyrrolidone, stirring uniformly, adding nano graphene, and pouring into a ball mill for ball milling to obtain graphene/modified strontium telluride mixed feed liquid;

the mass ratio of the modified strontium telluride nano material to the nano graphene to the N-methyl pyrrolidone is 1: 4.5-6.5: 10-15; the ball milling time is 2-4 h, and the ball milling revolution is 200-500 rpm;

s2, adding the graphene/modified strontium telluride mixed material liquid into a nano high-pressure homogenizer for dispersion treatment, and then transferring into a centrifugal spray drying tower for spray drying treatment to obtain graphene/modified strontium telluride mixed powder;

wherein the pressure of the high-pressure homogenizer is 50-100 MPa, the dispersion treatment time is 1-2 h, and the spray drying pressure is 10-20 MPa;

s3, adding the graphene/modified strontium telluride mixed powder into a crucible, then placing the crucible into a graphite furnace, carrying out heat treatment under the protection of inert gas, and cooling the crucible to room temperature to obtain an inorganic non-metal composite material;

wherein the temperature of the heat treatment is 220-300 ℃; the heat treatment time is 2-5 h.

Preferably, the water content of the graphene/modified strontium telluride mixed powder is less than or equal to 0.2%.

In a second aspect, the invention provides an application of an inorganic non-metallic composite material in electrochemical energy storage.

The invention has the beneficial effects that:

1. the invention provides a preparation method of an inorganic non-metallic composite material, and the prepared inorganic non-metallic composite material can replace graphite to be used as a negative electrode material in the conventional lithium ion battery. Compared with graphite, the inorganic non-metal composite material has better charge-discharge multiplying power, more excellent low-temperature performance and better compatibility with electrolyte.

2. The method comprises the steps of firstly preparing a strontium telluride nano material, then modifying the strontium telluride nano material by using potassium iodate, and then carrying out composite doping on the modified strontium telluride nano material and nano graphene to obtain the inorganic nonmetal composite material mixed and doped by the graphene and the strontium telluride grafted with bromine-oxygen bonds. The strontium telluride nano material prepared by the method is a white cubic crystal with NaCl lattices, is grafted with generated iodine oxidation bonds after being reacted with potassium iodate to obtain a modified strontium telluride nano material, is doped with nano graphene in an N-methylpyrrolidone environment, and is gradually evaporated and dissipated in a heat treatment step to obtain the inorganic nonmetal composite material.

3. According to the invention, a structural system of nano-graphene and the modified strontium telluride nano material is constructed, the surface of the material is provided with strontium telluride particles (cubic crystals) produced by nanowire guidance, the strontium telluride itself is used as a low-temperature heat-resistant material and has the obvious characteristics of a topological insulator, electrons can flow freely on the surface of the material, and meanwhile, the strontium telluride has stronger activity after being grafted with an iodine oxidation bond, so that ions can be rapidly inserted into/removed from a main material, better charge-discharge multiplying power is ensured, higher ionic conductivity of an electrolyte can be ensured, and the interface contact compatibility of an electrode and the electrolyte is better.

Detailed Description

The invention is further described with reference to the following examples.

Example 1

A preparation method of an inorganic non-metallic composite material comprises the following steps:

step 1, preparing a strontium telluride nano material:

reacting strontium chloride and sodium tellurite under the action of nitrilotriacetic acid to prepare a strontium telluride nano material;

step 2, preparing the modified strontium telluride nano material:

reacting potassium iodate with the strontium telluride nano material under an acidic condition to prepare a modified strontium telluride nano material;

step 3, preparing the inorganic non-metallic composite material:

and doping and mixing nano graphene and the modified strontium telluride nano material to obtain the inorganic non-metallic composite material.

The grain size of the strontium telluride nano material is 150 nm; the particle size of the modified strontium telluride nano material is 200 nm.

The acidic condition in step 2 means that the pH is 4.0.

The doping and mixing process in the step 3 sequentially comprises wet grinding, spray drying and heat treatment.

The step 1 specifically comprises the following steps:

s1, weighing strontium chloride, adding the strontium chloride into ammonia water, and completely dissolving to obtain a strontium chloride solution; weighing sodium tellurite, adding the sodium tellurite into deionized water, and stirring until the sodium tellurite is completely dissolved to obtain a sodium tellurite solution;

wherein the mass fraction of the ammonia water is 25%, the mass ratio of the strontium chloride to the ammonia water is 1:8, and the mass ratio of the sodium tellurite to the deionized water is 1: 15;

s2, slowly adding the sodium tellurite solution into the strontium chloride solution, stirring uniformly, then dropwise adding nitrilotriacetic acid while stirring, after dropwise adding, continuously stirring for 0.5-1 h, then pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in an oven with the temperature of 140-160 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the oven with the temperature of 80-100 ℃ for drying, and crushing into nanoparticles to obtain the strontium telluride nano material;

wherein the mass ratio of the strontium chloride solution, the sodium tellurite solution and the nitrilotriacetic acid is 1:3: 0.2.

The step 2 specifically comprises the following steps:

s1, weighing the potassium iodate, adding the potassium iodate into deionized water, stirring until the potassium iodate is completely dissolved, adding the strontium telluride nano material, and performing ultrasonic dispersion until the strontium telluride nano material is uniformly dispersed to obtain a strontium telluride/potassium iodate mixed solution;

wherein the mass ratio of the potassium iodate to the strontium telluride nano material to the deionized water is 1:3.8: 16;

s2, adding acid to adjust the pH value of the strontium telluride/potassium iodate mixed solution to 3.0-5.0, heating to 60-80 ℃, stirring for 0.5-2 h, pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in a drying oven with the temperature of 150-170 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the drying oven with the temperature of 80-100 ℃ for drying, and transferring into a nano crusher for crushing into nano particles to obtain the modified strontium telluride nano material.

In the step 2, in the process of adding acid for regulation, the added acid is nitric acid or hydrochloric acid.

The step 3 specifically comprises the following steps:

s1: adding the modified strontium telluride nano material into N-methyl pyrrolidone, stirring uniformly, adding nano graphene, and pouring into a ball mill for ball milling to obtain graphene/modified strontium telluride mixed feed liquid;

the mass ratio of the modified strontium telluride nano material to the nano graphene to the N-methyl pyrrolidone is 1:5.6: 12; the ball milling time is 3h, and the ball milling revolution is 300 rpm;

s2, adding the graphene/modified strontium telluride mixed material liquid into a nano high-pressure homogenizer for dispersion treatment, and then transferring into a centrifugal spray drying tower for spray drying treatment to obtain graphene/modified strontium telluride mixed powder;

wherein the pressure of the high-pressure homogenizer is 80MPa, the dispersion treatment time is 1.5h, and the spray drying pressure is 15 MPa;

s3, adding the graphene/modified strontium telluride mixed powder into a crucible, then placing the crucible into a graphite furnace, carrying out heat treatment under the protection of inert gas, and cooling the crucible to room temperature to obtain an inorganic non-metal composite material;

wherein the temperature of the heat treatment is 260 ℃; the heat treatment time is 3 h.

The water content of the graphene/modified strontium telluride mixed powder is less than or equal to 0.2%.

The prepared inorganic non-metallic composite material is applied to electrochemical energy storage.

Example 2

A preparation method of an inorganic non-metallic composite material comprises the following steps:

step 1, preparing a strontium telluride nano material:

reacting strontium chloride and sodium tellurite under the action of nitrilotriacetic acid to prepare a strontium telluride nano material;

step 2, preparing the modified strontium telluride nano material:

reacting potassium iodate with the strontium telluride nano material under an acidic condition to prepare a modified strontium telluride nano material;

step 3, preparing the inorganic non-metallic composite material:

and doping and mixing nano graphene and the modified strontium telluride nano material to obtain the inorganic non-metallic composite material.

The grain size of the strontium telluride nano material is 100 nm; the particle size of the modified strontium telluride nano material is 150 nm.

The acidic condition in step 2 means that the pH is 3.0.

The doping and mixing process in the step 3 sequentially comprises wet grinding, spray drying and heat treatment.

The step 1 specifically comprises the following steps:

s1, weighing strontium chloride, adding the strontium chloride into ammonia water, and completely dissolving to obtain a strontium chloride solution; weighing sodium tellurite, adding the sodium tellurite into deionized water, and stirring until the sodium tellurite is completely dissolved to obtain a sodium tellurite solution;

wherein the mass fraction of the ammonia water is 20%, the mass ratio of the strontium chloride to the ammonia water is 1:5, and the mass ratio of the sodium tellurite to the deionized water is 1: 10;

s2, slowly adding the sodium tellurite solution into the strontium chloride solution, stirring uniformly, then dropwise adding nitrilotriacetic acid while stirring, after dropwise adding, continuously stirring for 0.5-1 h, then pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in an oven with the temperature of 140-160 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the oven with the temperature of 80-100 ℃ for drying, and crushing into nanoparticles to obtain the strontium telluride nano material;

wherein the mass ratio of the strontium chloride solution, the sodium tellurite solution and the nitrilotriacetic acid is 1:2.5: 0.1.

The step 2 specifically comprises the following steps:

s1, weighing the potassium iodate, adding the potassium iodate into deionized water, stirring until the potassium iodate is completely dissolved, adding the strontium telluride nano material, and performing ultrasonic dispersion until the strontium telluride nano material is uniformly dispersed to obtain a strontium telluride/potassium iodate mixed solution;

wherein the mass ratio of the potassium iodate to the strontium telluride nano material to the deionized water is 1:3.2: 12;

s2, adding acid to adjust the pH value of the strontium telluride/potassium iodate mixed solution to 3.0-5.0, heating to 60-80 ℃, stirring for 0.5-2 h, pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in a drying oven with the temperature of 150-170 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the drying oven with the temperature of 80-100 ℃ for drying, and transferring into a nano crusher for crushing into nano particles to obtain the modified strontium telluride nano material.

In the step 2, in the process of adding acid for regulation, the added acid is nitric acid or hydrochloric acid.

The step 3 specifically comprises the following steps:

s1: adding the modified strontium telluride nano material into N-methyl pyrrolidone, stirring uniformly, adding nano graphene, and pouring into a ball mill for ball milling to obtain graphene/modified strontium telluride mixed feed liquid;

the mass ratio of the modified strontium telluride nano material to the nano graphene to the N-methyl pyrrolidone is 1:4.5: 10; the ball milling time is 2h, and the ball milling revolution is 200 rpm;

s2, adding the graphene/modified strontium telluride mixed material liquid into a nano high-pressure homogenizer for dispersion treatment, and then transferring into a centrifugal spray drying tower for spray drying treatment to obtain graphene/modified strontium telluride mixed powder;

wherein the pressure of the high-pressure homogenizer is 50MPa, the dispersion treatment time is 1h, and the spray drying pressure is 10 MPa;

s3, adding the graphene/modified strontium telluride mixed powder into a crucible, then placing the crucible into a graphite furnace, carrying out heat treatment under the protection of inert gas, and cooling the crucible to room temperature to obtain an inorganic non-metal composite material;

wherein the temperature of the heat treatment is 220 ℃; the heat treatment time is 2 h.

The water content of the graphene/modified strontium telluride mixed powder is less than or equal to 0.2%.

The prepared inorganic non-metallic composite material is applied to electrochemical energy storage.

Example 3

A preparation method of an inorganic non-metallic composite material comprises the following steps:

step 1, preparing a strontium telluride nano material:

reacting strontium chloride and sodium tellurite under the action of nitrilotriacetic acid to prepare a strontium telluride nano material;

step 2, preparing the modified strontium telluride nano material:

reacting potassium iodate with the strontium telluride nano material under an acidic condition to prepare a modified strontium telluride nano material;

step 3, preparing the inorganic non-metallic composite material:

and doping and mixing nano graphene and the modified strontium telluride nano material to obtain the inorganic non-metallic composite material.

The grain size of the strontium telluride nano material is 200 nm; the particle size of the modified strontium telluride nano material is 250 nm.

The acidic condition in step 2 means that the pH is 5.0.

The doping and mixing process in the step 3 sequentially comprises wet grinding, spray drying and heat treatment.

The step 1 specifically comprises the following steps:

s1, weighing strontium chloride, adding the strontium chloride into ammonia water, and completely dissolving to obtain a strontium chloride solution; weighing sodium tellurite, adding the sodium tellurite into deionized water, and stirring until the sodium tellurite is completely dissolved to obtain a sodium tellurite solution;

wherein the mass fraction of the ammonia water is 30%, the mass ratio of the strontium chloride to the ammonia water is 10, and the mass ratio of the sodium tellurite to the deionized water is 1: 20;

s2, slowly adding the sodium tellurite solution into the strontium chloride solution, stirring uniformly, then dropwise adding nitrilotriacetic acid while stirring, after dropwise adding, continuously stirring for 0.5-1 h, then pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in an oven with the temperature of 140-160 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the oven with the temperature of 80-100 ℃ for drying, and crushing into nanoparticles to obtain the strontium telluride nano material;

wherein the mass ratio of the strontium chloride solution, the sodium tellurite solution and the nitrilotriacetic acid is 1:3.5: 0.3.

The step 2 specifically comprises the following steps:

s1, weighing the potassium iodate, adding the potassium iodate into deionized water, stirring until the potassium iodate is completely dissolved, adding the strontium telluride nano material, and performing ultrasonic dispersion until the strontium telluride nano material is uniformly dispersed to obtain a strontium telluride/potassium iodate mixed solution;

wherein the mass ratio of the potassium iodate to the strontium telluride nano material to the deionized water is 1:4.5: 18;

s2, adding acid to adjust the pH value of the strontium telluride/potassium iodate mixed solution to 3.0-5.0, heating to 60-80 ℃, stirring for 0.5-2 h, pouring into a reaction kettle with a polytetrafluoroethylene lining, placing the reaction kettle in a drying oven with the temperature of 150-170 ℃ for treating for 8-10 h, filtering and collecting solids, washing the collected solids with acetone for three times, then washing with purified water for three times, then placing in the drying oven with the temperature of 80-100 ℃ for drying, and transferring into a nano crusher for crushing into nano particles to obtain the modified strontium telluride nano material.

In the step 2, in the process of adding acid for regulation, the added acid is nitric acid or hydrochloric acid.

The step 3 specifically comprises the following steps:

s1: adding the modified strontium telluride nano material into N-methyl pyrrolidone, stirring uniformly, adding nano graphene, and pouring into a ball mill for ball milling to obtain graphene/modified strontium telluride mixed feed liquid;

the mass ratio of the modified strontium telluride nano material to the nano graphene to the N-methyl pyrrolidone is 1:6.5: 15; the ball milling time is 4h, and the ball milling revolution is 500 rpm;

s2, adding the graphene/modified strontium telluride mixed material liquid into a nano high-pressure homogenizer for dispersion treatment, and then transferring into a centrifugal spray drying tower for spray drying treatment to obtain graphene/modified strontium telluride mixed powder;

wherein the pressure of the high-pressure homogenizer is 100MPa, the dispersion treatment time is 2h, and the spray drying pressure is 20 MPa;

s3, adding the graphene/modified strontium telluride mixed powder into a crucible, then placing the crucible into a graphite furnace, carrying out heat treatment under the protection of inert gas, and cooling the crucible to room temperature to obtain an inorganic non-metal composite material;

wherein the temperature of the heat treatment is 300 ℃; the heat treatment time is 5 h.

The water content of the graphene/modified strontium telluride mixed powder is less than or equal to 0.2%.

The prepared inorganic non-metallic composite material is applied to electrochemical energy storage.

Comparative example

Commercially available graphite is used as the inorganic nonmetallic material.

In order to illustrate the invention more clearly, the inorganic non-metallic composite materials prepared in the embodiments 1 to 3 and the comparative example are applied to the lithium ion battery, and the performance of the inorganic non-metallic composite materials is detected as follows:

1. preparing a battery:

(1) preparing a negative plate: the inorganic non-metal composite materials (inorganic non-metal materials) prepared in examples 1 to 3 and comparative example were used as negative electrode active materials, and the negative electrode active material, acetylene black, and PVDF were mixed in a weight ratio of 100: 4: 5 dissolving in N-methyl pyrrolidone, stirring, coating on aluminum foil, baking at 100 + -5 deg.C, tabletting, cutting into pieces, and rolling into negative plate;

(2) preparing a positive plate: lithium cobaltate was used as a positive electrode active material, and lithium cobaltate, acetylene black, and PVDF were mixed in a weight ratio of 100: 3: 6 dissolving in N-methyl pyrrolidone, uniformly stirring, coating on a copper foil, baking at the temperature of 100 +/-5 ℃, tabletting, cutting into pieces and rolling and cutting into positive plates by using a conventional method;

(3) and (2) winding the positive and negative plates and the polypropylene diaphragm into a square lithium ion battery core, collecting the lithium ion battery core in a battery case, welding, injecting 1.0mol/L LiPF6/EC + EMC + DMC (wherein the mass ratio of EC, EMC and DMC is 1: 1: 1) electrolyte, and sealing to obtain the lithium ion battery.

2. And (3) rate performance test:

the assay conditions were sequentially using 0.1C cycle 5 weeks, 0.2C cycle 5 weeks, 0.5C cycle 5 weeks, 1C cycle 5 weeks, 2C cycle 5 weeks and 0.1C cycle 5 weeks, according to the formula:

rate capability (%) -0.1C specific charge capacity in the last step/0.1C specific charge capacity in the first step,

the multiplying power performance is calculated, and the result is shown in the table 1.

3. And (3) low-temperature performance test:

the battery is placed for 5min at room temperature (25 ℃), firstly charged by 1C, cut to 3.8V, charged at constant voltage of 3.8V, cut to 0.1C, placed for 5min, discharged by 1C to obtain the battery capacity at 25 ℃, then the constant current charging is carried out at room temperature (25 ℃) and 1C is kept at low temperature (-40 ℃, -20 ℃) for discharging, and after the low-temperature test is completed, the low-temperature discharge capacity retention rate is calculated.

The low-temperature discharge capacity retention rate was calculated as follows:

low-temperature discharge capacity retention (%) - (discharge capacity at-40 ℃ or-20 ℃ (discharge capacity at 25 ℃) x 100%.

Table 1 performance testing of batteries prepared with different negative active materials

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.