Mixed conductive polymer coated tin carbon negative electrode material, preparation method thereof, negative electrode sheet, sodium ion battery and electrical equipment

Abstract

The application provides a mixed electric-conducting polymer coated tin-carbon negative electrode material and a preparation method thereof, a negative electrode sheet, a sodium ion battery and an electrical equipment, and relates to the technical field of new energy sources. The preparation method of the mixed electric-conducting polymer coated tin-carbon negative electrode material of the application is to perform a hydrothermal reaction on a carboxyl-rich organic tin source and a hydroxyl-rich carbon source as raw materials. The carboxyl-rich organic tin source is first decomposed into tin oxide and a carboxyl functional group by heat, the carboxyl functional group is esterified and crosslinked with the hydroxyl-rich carbon source, a spherical carbon precursor and a tin oxide precursor are formed, the tin oxide precursor is in-situ reduced to a tin core by carbon at high temperature, the esterification and crosslinking structure forms an amorphous carbon shell on the surface, a spherical tin-carbon negative electrode material is obtained, and then the material is mixed with a polymer solid-state electrolyte and an electronic conductive material, dried, and subjected to microwave treatment. The electronic conductive material receives a microwave magnetic field to heat, so that the mixed electric-conducting polymer material and the amorphous carbon shell are enhanced in action, and a uniform and firm mixed electric-conducting polymer coating layer is formed.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a mixed conductive polymer-coated tin-carbon negative electrode material and a preparation method thereof, a negative electrode sheet, a sodium ion battery and electrical equipment. Background Art

[0002] The negative electrode materials of sodium ion batteries mainly include carbonaceous materials, metals (such as Sn, Sb, Ge) and metal oxides. Among them, metal Sn materials have attracted much attention. Metal Sn can form alloys with Na 15 Sn4 has a theoretical capacity of up to 837 mAh / g. However, the huge volume expansion effect of pure Sn electrodes leads to structural damage. The sodium insertion process produces a huge volume expansion. As a result, the negative electrode active material is easily broken and pulverized during the charge and discharge process, making it difficult to form a stable SEI film on the surface, resulting in rapid capacity decay and poor cycle performance. Summary of the Invention

[0003] The purpose of this application is to provide a mixed conductive polymer-coated tin-carbon negative electrode material and its preparation method, negative electrode sheet, sodium ion battery and electrical equipment, aiming to solve the problem that the capacity of existing pure Sn electrodes decays too quickly and the cycle performance is very poor.

[0004] To achieve the above objectives, the present application provides a hybrid conductive polymer-coated tin-carbon negative electrode material, comprising: a single tin core, an amorphous carbon shell coating the single tin core, and a hybrid conductive polymer coating layer coating the amorphous carbon shell, wherein the hybrid conductive polymer coating layer has ionic conductivity and electronic conductivity.

[0005] In some embodiments, the mixed conductive polymer coating comprises a polymer solid electrolyte and an electronically conductive material;

[0006] Optionally, the electronically conductive material includes one or a combination of conductive carbon black, conductive graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, and carbon fibers;

[0007] Optionally, the polymer solid electrolyte includes one or a combination of polyethylene oxide, polyacrylonitrile, and poly(methyl methacrylate);

[0008] Optionally, the mass ratio of the polymer solid electrolyte to the electronic conductive material is 1:100 to 100:1.

[0009] In some embodiments, at least one of the following conditions is met:

[0010] A. The diameter of the elemental tin core is 100-2000 nm;

[0011] B. the thickness of the amorphous carbon shell is 10-200 nm;

[0012] C. The thickness of the mixed conductive polymer coating is 10-200 nm;

[0013] D. The particle size of the mixed conductive polymer-coated tin-carbon negative electrode material is 200 nm-5 μm;

[0014] E. The ratio of the mass of the mixed conductive polymer coating to the sum of the masses of the elemental tin core and the amorphous carbon shell is (0.1-20):100;

[0015] F. The ionic conductivity of the mixed conductive polymer coating is 10 -1 S / cm-10 -3 S / cm;

[0016] G. The electronic conductivity of the mixed conductive polymer coating is 10 -3 S / cm-10 2 S / cm.

[0017] The present application also provides a method for preparing a mixed conductive polymer-coated tin-carbon negative electrode material, comprising:

[0018] Mixing a carboxyl-rich organic tin source, a hydroxyl-rich carbon source and first water to perform a hydrothermal reaction to obtain a precursor;

[0019] Carbonizing the precursor in an inert atmosphere to obtain a carbonized material;

[0020] The carbonized material is mixed with a polymer solid electrolyte, an electronically conductive material, and a second water, dried, and subjected to microwave treatment to obtain the mixed electrically conductive polymer-coated tin-carbon negative electrode material.

[0021] In some embodiments, at least one of the following conditions is met:

[0022] A. the carboxyl-rich organic tin source comprises one or a combination of tin oxalate, dimethyltin, dioctyltin, tetraphenyltin, tin methanesulfonate, and dibutyltin;

[0023] B. The hydroxyl-rich carbon source comprises one or a combination of glucose, sucrose, maltose, lactose, fructose, starch, and cellulose;

[0024] C. The mass ratio of the carboxyl-rich organotin source to the hydroxyl-rich carbon source is (1-20):100;

[0025] D. the ratio of the sum of the mass of the carboxyl-rich organotin source and the hydroxyl-rich carbon source to the mass of the first water is 1:(1-20);

[0026] E. The temperature of the hydrothermal reaction is 50-200°C and the time is 2-12 hours.

[0027] In some embodiments, at least one of the following conditions is met:

[0028] A. The inert atmosphere is an inert atmosphere or an oxygen-deficient atmosphere; the inert atmosphere includes any one or a combination of nitrogen atmosphere, argon atmosphere, neon atmosphere, helium atmosphere, xenon atmosphere or krypton atmosphere; the oxygen-deficient atmosphere is a gas atmosphere with an oxygen content of ≤1 wt%;

[0029] B. The carbonization temperature is 400-800°C and the holding time is 0.5-24h;

[0030] Optionally, the carbonization temperature is 500° C.-600° C., and the holding time is 1-5 hours.

[0031] In some embodiments, at least one of the following conditions is met:

[0032] A. The ratio of the sum of the mass of the polymer solid electrolyte and the electronic conductive material to the mass of the carbonized material is (0.1-20):100;

[0033] B. The carbonized material is mixed with the polymer solid electrolyte, the electronic conductive material, and the second water at a stirring speed of 100-3000 rpm and a stirring time of 0.5-24 h;

[0034] C. The drying temperature is 50-200°C;

[0035] D. The microwave frequency of the microwave treatment is 100-3000 Hz, and the time of the microwave treatment is 10s-120s.

[0036] The present application also provides a negative electrode sheet, comprising the mixed conductive polymer-coated tin-carbon negative electrode material as described above, or comprising the mixed conductive polymer-coated tin-carbon negative electrode material prepared by the preparation method described above.

[0037] The present application also provides a sodium ion battery, comprising the above-mentioned negative electrode sheet.

[0038] The present application also provides an electrical device, comprising the above-mentioned sodium ion battery.

[0039] Compared with the prior art, the advantages of this application include:

[0040] The hybrid conductive polymer-coated tin-carbon negative electrode material provided in this application features an elemental tin core and an amorphous carbon shell as a first coating layer. The carbon layer possesses sufficient mechanical strength and toughness to limit the volume expansion of the tin. The second coating layer comprises a mixed layer of a polymer solid electrolyte and an electronically conductive material. The polymer solid electrolyte exhibits excellent elasticity and effectively suppresses volume expansion. While the first and second coating layers suppress volume expansion, the polymer solid electrolyte and electronically conductive material enhance ionic and electronic conductivity, making sodium ion insertion and extraction from the tin more uniform. This further protects the tin interface, improves interfacial stability, and thus enhances cycling performance.

[0041] The preparation method of the hybrid conductive polymer-coated tin-carbon negative electrode material provided in the present application uses a carboxyl-rich organic tin source and a hydroxyl-rich carbon source as raw materials for a hydrothermal reaction. The carboxyl-rich organic tin source is first decomposed into tin oxide and carboxyl functional groups by heat. The carboxyl functional groups and the hydroxyl-rich carbon source are esterified and cross-linked to form a spherical carbon precursor and a tin oxide precursor. The tin oxide precursor is reduced by carbon at high temperature to generate an elemental tin core in situ. The esterified cross-linked structure uniformly forms an amorphous carbon shell on the surface to obtain a spherical tin-carbon negative electrode material. The spherical tin-carbon negative electrode material is then mixed with a polymer solid electrolyte and an electronically conductive material, dried, and microwave-treated. The electronically conductive material receives heat from the microwave magnetic field, thereby enhancing the interaction between the hybrid conductive polymer material and the amorphous carbon shell, forming a uniform and firm hybrid conductive polymer coating layer.

[0042] The negative electrode sheet, sodium ion battery and electrical equipment provided in this application use the mixed conductive polymer-coated tin-carbon negative electrode material of this application, which has high capacity and good cycle performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0044] Figure 1 This is a schematic structural diagram of the hybrid conductive polymer-coated tin-carbon negative electrode material of the present application;

[0045] Figure 2 This is a schematic flow chart of the preparation method of the hybrid conductive polymer-coated tin-carbon negative electrode material of the present application;

[0046] Figure 3 This is an SEM image of the mixed conductive polymer-coated tin-carbon negative electrode material of Example 1;

[0047] Figure 4 Graphs showing the charge and discharge curve test results for Examples 1 to 3;

[0048] Figure 5Graphs showing the long cycle test results for Examples 1 to 3;

[0049] Figure 6 Graph showing the charge and discharge curve test results of Example 1 and Comparative Example 1;

[0050] Figure 7 Graph showing the long cycle test results of Example 1 and Comparative Example 1;

[0051] Figure 8 The charge and discharge curve test results of Example 1 and Comparative Example 2 are shown;

[0052] Figure 9 Graph showing the long cycle test results of Example 1 and Comparative Example 2;

[0053] Figure 10 Graph showing the charge and discharge curve test results of Example 1 and Comparative Example 3;

[0054] Figure 11 Graph showing the long cycle test results of Example 1 and Comparative Example 3;

[0055] Figure 12 Graph showing the charge and discharge curve test results of Example 1 and Comparative Example 4;

[0056] Figure 13 Graph showing the long cycle test results of Example 1 and Comparative Example 4;

[0057] Figure 14 Graph showing the charge and discharge curve test results of Example 1 and Comparative Example 5;

[0058] Figure 15 Graph showing the long cycle test results for Example 1 and Comparative Example 5. DETAILED DESCRIPTION

[0059] As used herein:

[0060] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0061] The conjunction "consisting of" excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim, rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0062] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed alone. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including the range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0063] In these examples, parts and percentages are by mass unless otherwise indicated.

[0064] "Parts by mass" refers to the basic unit of measurement used to express the mass ratio of multiple components. One part can represent any unit of mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, this means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, we could say that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number representing a multiplication factor). It's important to note that, unlike parts by mass, the sum of the mass of all components is not limited to 100 parts.

[0065] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0066] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0067] This application provides a mixed conductive polymer coated tin carbon negative electrode material, please refer to Figure 1, comprising: a single tin core, an amorphous carbon shell covering the single tin core, and a mixed conductive polymer coating layer covering the amorphous carbon shell, wherein the mixed conductive polymer coating layer has ionic conductivity and electronic conductivity.

[0068] The hybrid conductive polymer-coated tin-carbon negative electrode material provided in this application features an elemental tin core and an amorphous carbon shell as a first coating layer. The carbon layer possesses sufficient mechanical strength and toughness to limit the volume expansion of the tin. The second coating layer comprises a mixed layer of a polymer solid electrolyte and an electronically conductive material. The polymer solid electrolyte exhibits excellent elasticity and effectively suppresses volume expansion. While the first and second coating layers suppress volume expansion, the polymer solid electrolyte and electronically conductive material enhance ionic and electronic conductivity, making sodium ion insertion and extraction from the tin more uniform. This further protects the tin interface, improves interfacial stability, and thus enhances cycling performance.

[0069] In some embodiments, the mixed conductive polymer coating comprises a polymer solid electrolyte and an electronically conductive material.

[0070] In some embodiments, the electronically conductive material includes one or a combination of conductive carbon black, conductive graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, and carbon fibers.

[0071] In some embodiments, the polymer solid electrolyte includes one or a combination of polyethylene oxide, polyacrylonitrile, and poly(methyl methacrylate).

[0072] In some embodiments, the mass ratio of the polymer solid electrolyte to the electronic conductive material is 1:100 to 100:1, for example, it can be any ratio of 1:100, 1:90, 1:80, 1:70, 1:60, 1:50, 1:40, 1:30, 1:20, 1:10, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1 or a range between any two ratios, or any other ratio between 1:100 and 100:1 or any other range of values.

[0073] In some embodiments, the diameter of the elemental tin core is 100-2000 nm, for example, it can be any value of 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, 2000 nm or a range between any two values, or any other value between 100-2000 nm or any other range of values.

[0074] Optionally, the diameter of the elemental tin core is 800nm-2000nm.

[0075] In some embodiments, the thickness of the amorphous carbon shell is 10-200 nm, for example, any value of 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, or 200 nm, or a range between any two values, or any other value between 10-200 nm or any other range of values.

[0076] Optionally, the amorphous carbon shell has a thickness of 20-100 nm.

[0077] In some embodiments, the thickness of the mixed conductive polymer coating is 10-200 nm, for example, it can be any value of 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, or a range between any two values, or any other value between 10-200 nm or any other range of values.

[0078] Optionally, the thickness of the mixed conductive polymer coating layer is 20-100 nm.

[0079] In some embodiments, the particle size of the mixed conductive polymer-coated tin-carbon negative electrode material is 200 nm-5 μm, for example, it can be any value of 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, 2000 nm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or a range between any two values, or any other value between 200 nm and 5 μm or any other range of values.

[0080] Optionally, the particle size of the mixed conductive polymer-coated tin-carbon negative electrode material is 1 μm-5 μm.

[0081] In some embodiments, the ratio of the mass of the mixed conductive polymer coating to the sum of the masses of the elemental tin core and the amorphous carbon shell is (0.1-20):100, for example, it can be any ratio of 0.1:100, 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 10:100, 11:100, 12:100, 13:100, 14:100, 15:100, 16:100, 17:100, 18:100, 19:100, 20:100 or a range between any two ratios, or any other ratio between (0.1-20):100 or any other range of values.

[0082] In some embodiments, the ionic conductivity of the mixed conductive polymer coating is 10 -1 S / cm-10 -3 S / cm, for example, it can be 10 -1 S / cm, 8×10 -2 S / cm, 5×10 -2 S / cm, 10 -2 S / cm, 5×10 -3 S / cm, 10 -3 Any value or range between any two values ​​in S / cm, or 10 -1 S / cm-10 -3 Any other value or any other range of values ​​between S / cm.

[0083] In some embodiments, the electronic conductivity of the mixed conductive polymer coating is 10 -3 S / cm-10 2 S / cm, for example, it can be 10 -3 S / cm, 5×10-3 S / cm, 10 -2 S / cm, 5×10 -2 S / cm, 10 -1 S / cm, 5×10 -1 S / cm, 10 1 S / cm, 5×10 1 S / cm, 10 2 Any value or range between any two values ​​in S / cm, or 10 -3 S / cm-10 2 Any other value or any other range of values ​​between S / cm.

[0084] This application also provides a method for preparing a mixed conductive polymer coated tin-carbon negative electrode material. Figure 2 ,include:

[0085] S100: mixing a carboxyl-rich organic tin source, a hydroxyl-rich carbon source, and first water to perform a hydrothermal reaction to obtain a precursor;

[0086] S200: carbonizing the precursor in an inert atmosphere to obtain a carbonized material;

[0087] S300: mixing the carbonized material with a polymer solid electrolyte, an electronically conductive material, and a second water, drying the mixture, and subjecting the mixture to microwave treatment to obtain a mixed conductive polymer-coated tin-carbon negative electrode material.

[0088] The preparation method of the hybrid conductive polymer-coated tin-carbon negative electrode material provided in the present application uses a carboxyl-rich organic tin source and a hydroxyl-rich carbon source as raw materials for a hydrothermal reaction. The carboxyl-rich organic tin source is first decomposed into tin oxide and carboxyl functional groups by heat. The carboxyl functional groups and the hydroxyl-rich carbon source are esterified and cross-linked to form a spherical carbon precursor and a tin oxide precursor. The tin oxide precursor is reduced by carbon at high temperature to generate an elemental tin core in situ. The esterified cross-linked structure uniformly forms an amorphous carbon shell on the surface to obtain a spherical tin-carbon negative electrode material. The spherical tin-carbon negative electrode material is then mixed with a polymer solid electrolyte and an electronically conductive material, dried, and microwave-treated. The electronically conductive material receives heat from the microwave magnetic field, thereby enhancing the interaction between the hybrid conductive polymer material and the amorphous carbon shell, forming a uniform and firm hybrid conductive polymer coating layer.

[0089] In some embodiments, the carboxyl-rich organic tin source in step S100 includes one or a combination of tin oxalate, dimethyltin, dioctyltin, tetraphenyltin, methyl tin sulfonate, and dibutyltin; the hydroxyl-rich carbon source includes one or a combination of glucose, sucrose, maltose, lactose, fructose, starch, and cellulose.

[0090] In some embodiments, the mass ratio of the carboxyl-rich organotin source to the hydroxyl-rich carbon source in step S100 is (1-20):100, for example, it can be any ratio of 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 10:100, 11:100, 12:100, 13:100, 14:100, 15:100, 16:100, 17:100, 18:100, 19:100, 20:100, or a range between any two ratios, or any other ratio between (1-20):100 or any other range of values.

[0091] In some embodiments, the ratio of the sum of the masses of the carboxyl-rich organic tin source and the hydroxyl-rich carbon source in step S100 to the mass of the first water is 1:(1-20), for example, it can be any ratio of 1:1, 1:5, 1:10, 1:15, 1:20 or a range between any two ratios, or any other ratio between 1:(1-20) or any other range of values.

[0092] In some embodiments, the temperature of the hydrothermal reaction in step S100 is 50-200°C, for example, it can be any value of 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, or a range between any two values, or any other value between 50-200°C or any other range of values, and the time is 2-12 hours, for example, it can be any value of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or a range between any two values, or any other value between 2-12 hours or any other range of values.

[0093] In some embodiments, the inert atmosphere in step S200 is an inert atmosphere or an oxygen-deficient atmosphere; the inert atmosphere includes any one or a combination of nitrogen atmosphere, argon atmosphere, neon atmosphere, helium atmosphere, xenon atmosphere or krypton atmosphere; the oxygen-deficient atmosphere is a gas atmosphere with an oxygen content ≤1wt%.

[0094] In some embodiments, the carbonization temperature in step S200 is 400°C-800°C, for example, it can be any value of 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, or a range between any two values, or any other value between 400°C and 800°C, or any other range of values, and the holding time is 0.5-24h, for example, it can be any value of 0.5h, 1h, 2h, 5h, 10h, 12h, 15h, 18h, 20h, 22h, 24h, or a range between any two values, or any other value between 0.5-24h or any other range of values.

[0095] Optionally, the carbonization temperature is 500° C.-600° C., and the holding time is 1-5 hours.

[0096] In some embodiments, the ratio of the sum of the masses of the polymer solid electrolyte and the electronic conductive material to the mass of the carbonized material in step S300 is (0.1-20):100, for example, it can be any ratio of 0.1:100, 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 10:100, 11:100, 12:100, 13:100, 14:100, 15:100, 16:100, 17:100, 18:100, 19:100, 20:100 or a range between any two ratios, or it can be any other ratio between (0.1-20):100 or any other range of values.

[0097] In some embodiments, in step S300 , the carbonized material is mixed with the polymer solid electrolyte, the electronic conductive material, and the second water at a stirring speed of 100-3000 rpm and a stirring time of 0.5-24 h.

[0098] In some embodiments, the drying temperature in step S300 is 50-200°C, for example, it can be any value of 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or a range between any two values, or any other value between 50-200°C or any other range of values.

[0099] In some embodiments, the microwave frequency of the microwave treatment in step S300 is 100-3000 Hz, for example, it can be any value of 100 Hz, 200 Hz, 300 Hz, 500 Hz, 800 Hz, 1000 Hz, 1200 Hz, 1500 Hz, 1700 Hz, 2000 Hz, 2300 Hz, 2500 Hz, 2800 Hz, or 3000 Hz, or a range between any two values, or any other value between 100-3000 Hz, or any other range of values, and the time of the microwave treatment is 10s-120s, for example, it can be any value of 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, or 120s, or a range between any two values, or any other value between 10s and 120s, or any other range of values.

[0100] The present application also provides a negative electrode sheet, comprising the mixed conductive polymer-coated tin-carbon negative electrode material as described above, or comprising the mixed conductive polymer-coated tin-carbon negative electrode material prepared by the preparation method described above.

[0101] The present application also provides a sodium ion battery, comprising the above-mentioned negative electrode sheet.

[0102] The present application also provides an electrical device, comprising the above-mentioned sodium ion battery.

[0103] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0104] Example 1

[0105] This embodiment provides a mixed conductive polymer-coated tin-carbon negative electrode material, the preparation method of which includes the following steps:

[0106] (1) Tin oxalate and glucose are mixed evenly in a mass ratio of 1:10, and pure water of equal mass to the powder is added, placed in a reactor, heated to 120°C, kept warm for 8 hours, and cooled to room temperature to obtain a spherical precursor, wherein the precursor includes a carbon precursor and a tin oxide precursor.

[0107] (2) The precursor obtained by the reaction in step (1) was taken out, crushed by ball milling to a median particle size of about 5.0 μm, and added to a tubular furnace. The temperature was raised to 500° C. in a nitrogen atmosphere in the tubular furnace, kept warm for 3 h, and cooled to obtain a spherical carbonized tin-carbon negative electrode material.

[0108] (3) The carbonized material was then mixed with polymer solid electrolyte ethylene oxide and electronic conductive material single-walled carbon nanotubes in a mass ratio of 100:15:1, and pure water of equal mass to the powder was added. The mixture was stirred at a speed of 2000 r / min for 2 hours, centrifuged to remove the filtrate, and dried at 80°C. The dried material was then placed in a microwave treatment instrument, the microwave frequency was set to 2000 Hz, and the microwave treatment time was 30 seconds to obtain the mixed conductive polymer-coated tin-carbon negative electrode material of Example 1, the SEM image of which is shown as follows: Figure 3 shown.

[0109] Example 2

[0110] This embodiment provides a mixed conductive polymer-coated tin-carbon negative electrode material, the preparation method of which includes the following steps:

[0111] (1) Tin methanesulfonate and cellulose are mixed evenly in a mass ratio of 15:100, and pure water twice the mass of the powder is added, placed in a reactor, heated to 150°C, kept warm for 5 hours, and cooled to room temperature to obtain a spherical precursor, wherein the precursor includes a carbon precursor and a tin oxide precursor.

[0112] (2) The precursor obtained by the reaction in step (1) was taken out, crushed by ball milling to a median particle size of about 7.0 μm, and added to a tubular furnace. The temperature was raised to 600° C. in a nitrogen atmosphere in the tubular furnace, kept warm for 2 h, and cooled to obtain a spherical carbonized tin-carbon negative electrode material.

[0113] (3) The carbonized material was then mixed with a polymer solid electrolyte (polyacrylonitrile) and an electronically conductive material (carbon black) in a mass ratio of 100:6:4. Pure water (twice the mass of the powder) was added, stirred at a speed of 1000 r / min for 4 h, centrifuged to remove the filtrate, and dried at 100° C. The dried material was then placed in a microwave processing instrument, the microwave frequency was set to 1000 Hz, and the microwave treatment time was 60 s to obtain the mixed conductive polymer-coated tin-carbon negative electrode material of Example 2.

[0114] Example 3

[0115] This embodiment provides a mixed conductive polymer-coated tin-carbon negative electrode material, the preparation method of which includes the following steps:

[0116] (1) Dimethyltin and starch are mixed evenly in a mass ratio of 1:5, and pure water 10 times the mass of the powder is added, placed in a reactor, heated to 80°C, kept warm for 12 hours, and cooled to room temperature to obtain a spherical precursor, wherein the precursor includes a carbon precursor and a tin oxide precursor.

[0117] (2) The precursor obtained by the reaction in step (1) was taken out, ball-milled to a median particle size of about 3.0 μm, and added to a tubular furnace. The temperature was raised to 500° C. in a nitrogen atmosphere in the tubular furnace, kept warm for 24 h, and cooled to obtain a spherical carbonized tin-carbon negative electrode material.

[0118] (3) The carbonized material was then mixed with a polymer solid electrolyte, poly(methyl methacrylate), and an electronically conductive material, multi-walled carbon nanotubes, in a mass ratio of 100:18:2. Pure water (1.5 times the mass of the powder) was added, and the mixture was stirred at a speed of 3000 r / min for 1.5 hours. The filtrate was removed by centrifugation, and the mixture was dried at 60°C. The dried material was then placed in a microwave processing apparatus, the microwave frequency was set to 3000 Hz, and the microwave treatment time was 10 seconds, to obtain the mixed conductive polymer-coated tin-carbon negative electrode material of Example 3.

[0119] Comparative Example 1

[0120] This comparative example provides a mixed conductive polymer-coated tin-carbon negative electrode material, and the preparation method thereof comprises the following steps:

[0121] (1) Glucose and sodium hydroxide were mixed in a 1:1 mass ratio and placed in a tube furnace. The mixture was heated to 500°C under a nitrogen atmosphere, kept at this temperature for 3 hours, and cooled to obtain porous hard carbon. The porous hard carbon and molten metal tin were mixed in a mass ratio of 10:1 and ball milled to obtain tin-doped hard carbon material.

[0122] (2) The tin-doped hard carbon material obtained in step (1) was mixed with a polymer solid electrolyte ethylene oxide and an electronically conductive material single-walled carbon nanotube in a mass ratio of 100:15:1. Pure water of equal mass to the powder was added, and the mixture was stirred at a speed of 2000 r / min for 2 h. The filtrate was removed by centrifugation and then dried at 80° C. The dried material was then placed in a microwave treatment apparatus, the microwave frequency was set to 2000 Hz, and the microwave treatment time was 30 s to obtain the mixed conductive polymer-coated tin-carbon negative electrode material having a core of the tin-doped porous carbon material as in Comparative Example 1.

[0123] Comparative Example 2

[0124] Comparative Example 2 provides a carbon-coated composite tin-carbon negative electrode material, the preparation method of which differs from that of Example 1 in that: step (3) is not performed in Comparative Example 2, and the material obtained in step (2) is not added with a polymer solid electrolyte and an electronic conductive material for microwave treatment to obtain a spherical single-layer carbon-coated composite tin-carbon negative electrode material.

[0125] Comparative Example 3

[0126] Comparative Example 3 provides a double-layer carbon-coated composite tin-carbon negative electrode material. The difference between its preparation method and Example 1 is that: the microwave frequency in step (3) is set to 4000 Hz, the microwave treatment time is 600 s, and the coating layer is completely carbonized by microwaves to obtain a double-layer carbon-coated composite tin-carbon negative electrode material.

[0127] Comparative Example 4

[0128] Comparative Example 4 provides a polymer solid electrolyte coated tin-carbon negative electrode material, and its preparation method differs from that of Example 1 in that: in Comparative Example 4, no electronic conductive material is added for microwave treatment in step (3) to obtain a polymer electrolyte coated composite tin-carbon negative electrode material.

[0129] Comparative Example 5

[0130] Comparative Example 5 provides an electronically conductive coated tin-carbon negative electrode material, the preparation method of which differs from that of Example 1 in that: in Comparative Example 5, no polymer solid electrolyte material is added for microwave treatment in step (3) to obtain an electronically conductive coated composite tin-carbon negative electrode material.

[0131] The electrochemical performance of the tin-carbon negative electrode materials obtained in each embodiment and comparative example was tested. The button battery electrode was prepared by a method known in the art: the negative electrode material, the conductive agent, and the binder were mixed in a mass percentage of 91:3:6, and the solid content was adjusted to 50% with deionized water. The mixture was evenly coated on a copper foil current collector, vacuum dried, and rolled to a surface density of 5.5±0.5 mg / cm 2 , and the negative electrode sheet is obtained.

[0132] Button cell production: sodium sheet is used as the counter electrode, 1 mol / L NaPF6 / DIGLYME (100 Vol%) is used as the electrolyte, glass fiber is used as the separator, and a 2032 button cell shell is used to assemble the button half cell.

[0133] The electrochemical test results of Examples 1 to 3 are as follows: Figure 4 and Figure 5 As shown, the electrochemical test results of Example 1 and Comparative Example 1 are as follows Figure 6 and Figure 7 As shown, the electrochemical test results of Example 1 and Comparative Example 2 are as follows Figure 8 and Figure 9 As shown, the electrochemical test results of Example 1 and Comparative Example 3 are as follows Figure 10 and Figure 11 As shown, the electrochemical test results of Example 1 and Comparative Example 4 are as follows Figure 12 and Figure 13 As shown, the electrochemical test results of Example 1 and Comparative Example 5 are as follows Figure 14 and Figure 15 shown.

[0134] The electrochemical properties of the tin-carbon negative electrode materials of various embodiments and comparative examples are shown in Table 1.

[0135] Table 1 Electrochemical properties of tin-carbon negative electrode materials in various embodiments and comparative examples

[0136]

[0137] According to Table 1, the number of cycles of the tin-carbon negative electrode materials of Examples 1 to 3 of the present application with a cycle capacity retention rate of 90% can all reach more than 1,000 times, while the number of cycles of the comparative solution with a cycle capacity retention rate of 90% can only reach 571 times at most. Among them, the mixed conductive polymer-coated tin-carbon negative electrode material with the core of comparative example 1 being a tin-doped porous carbon material has higher charge and discharge capacity and first effect than the embodiment solution, but its number of cycles is only 94 times. In comparative example 1, the metallic tin exists in the porous carbon and is not completely coated as in Example 1. Part of the metallic tin is exposed. Although the reaction area between the metallic tin and the electrolyte is increased to a certain extent, making the first effect and charge and discharge capacity higher, the interface of the exposed part of the metallic tin deteriorates after multiple cycles, causing the material to expand, crack and pulverize, resulting in a significant decrease in cycle performance.

[0138] The single-layer carbon-coated composite tin carbon negative electrode material of Comparative Example 2, the double-layer carbon-coated composite tin carbon negative electrode material of Comparative Example 3, the polymer electrolyte-coated composite tin carbon negative electrode material of Comparative Example 4, and the electronic conductivity-coated composite tin carbon negative electrode material of Comparative Example 5 are all inferior to the embodiment scheme in terms of charge and discharge capacity, first efficiency, and the number of cycles with a cycle capacity retention rate of 90%. This is because Comparative Examples 2 and 3 do not have a mixed conductive polymer coating layer composed of a polymer solid electrolyte and an electronic conductive material, and their ionic conductivity and electronic conductivity are poor. The sodium ions are not uniformly embedded in / out of tin, and the interface of tin cannot be protected to enhance stability, thereby affecting the cycle performance. The second coating layer of Comparative Example 4 has only ionic conductivity and poor electronic conductivity, which can easily increase the polarization of the battery during multiple cycles, affecting the cycle performance; the second coating layer of Comparative Example 5 has only electronic conductivity and poor ionic conductivity, and the sodium ions are not uniformly embedded in / out of metal tin and the speed is slow, which can easily cause local enrichment and deposition of sodium ions, affecting the cycle performance.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

[0140] Furthermore, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and to form distinct embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is intended solely to enhance understanding of the overall background of this application and should not be construed as an admission or any implication that such information constitutes prior art known to those skilled in the art.

Claims

1. A mixed conductive polymer coated tin-carbon negative electrode material, characterized in that: include: A single tin core, an amorphous carbon shell covering the single tin core, and a mixed conductive polymer coating layer covering the amorphous carbon shell, wherein the mixed conductive polymer coating layer has ionic conductivity and electronic conductivity; The mixed conductive polymer coating layer includes a polymer solid electrolyte and an electronic conductive material; The electronic conductive material includes one or a combination of conductive carbon black, conductive graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, and carbon fibers; The polymer solid electrolyte includes one or a combination of polyethylene oxide and polyacrylonitrile.

2. The hybrid conductive polymer-coated tin-carbon negative electrode material according to claim 1, characterized in that: The mass ratio of the polymer solid electrolyte to the electronic conductive material is 1:100 to 100:

1.

3. The hybrid conductive polymer-coated tin-carbon negative electrode material according to claim 1 or 2, characterized in that: At least one of the following conditions is met: A. The diameter of the elemental tin core is 100-2000 nm; B. the thickness of the amorphous carbon shell is 10-200 nm; C. The thickness of the mixed conductive polymer coating is 10-200 nm; D. The particle size of the mixed conductive polymer-coated tin-carbon negative electrode material is 200 nm-5 μm; E. The ratio of the mass of the mixed conductive polymer coating layer to the sum of the masses of the elemental tin core and the amorphous carbon shell is (0.1-20): 100; F. The ionic conductivity of the mixed conductive polymer coating is 10 -1 S / cm-10 -3 S / cm; G. The electronic conductivity of the mixed conductive polymer coating is 10 -3 S / cm-10 2 S / cm.

4. A method for preparing the hybrid conductive polymer-coated tin-carbon negative electrode material according to any one of claims 1 to 3, characterized in that: include: Mixing a carboxyl-rich organic tin source, a hydroxyl-rich carbon source and first water to perform a hydrothermal reaction to obtain a precursor; Carbonizing the precursor in an inert atmosphere to obtain a carbonized material; The carbonized material is mixed with a polymer solid electrolyte, an electronically conductive material, and a second water, dried, and subjected to microwave treatment to obtain the mixed electrically conductive polymer-coated tin-carbon negative electrode material.

5. The method for preparing the mixed conductive polymer-coated tin-carbon negative electrode material according to claim 4, characterized in that: At least one of the following conditions is met: A. the carboxyl-rich organic tin source comprises tin oxalate; B. The hydroxyl-rich carbon source comprises one or a combination of glucose, sucrose, maltose, lactose, fructose, starch, and cellulose; C. The mass ratio of the carboxyl-rich organotin source to the hydroxyl-rich carbon source is (1-20):100; D. the ratio of the sum of the mass of the carboxyl-rich organotin source and the hydroxyl-rich carbon source to the mass of the first water is 1:(1-20); E. The temperature of the hydrothermal reaction is 50-200°C and the time is 2-12 hours.

6. The method for preparing a hybrid conductive polymer-coated tin-carbon negative electrode material according to claim 4, characterized in that: At least one of the following conditions is met: A. The inert atmosphere is an inert atmosphere or an oxygen-deficient atmosphere; the inert atmosphere includes any one or a combination of nitrogen atmosphere, argon atmosphere, neon atmosphere, helium atmosphere, xenon atmosphere or krypton atmosphere; the oxygen-deficient atmosphere is a gas atmosphere with an oxygen content of ≤1 wt%; B. The carbonization temperature is 400°C-800°C, and the holding time is 0.5-24h.

7. The method for preparing a hybrid conductive polymer-coated tin-carbon negative electrode material according to claim 6, characterized in that: The carbonization temperature is 500° C.-600° C., and the holding time is 1-5 hours.

8. The method for preparing a hybrid conductive polymer-coated tin-carbon negative electrode material according to claim 4, characterized in that: At least one of the following conditions is met: A. The ratio of the sum of the mass of the polymer solid electrolyte and the electronic conductive material to the mass of the carbonized material is (0.1-20):100; B. The carbonized material is mixed with the polymer solid electrolyte, the electronic conductive material, and the second water at a stirring speed of 100-3000 rpm and a stirring time of 0.5-24 h; C. The drying temperature is 50-200°C; D. The microwave frequency of the microwave treatment is 100-3000 Hz, and the time of the microwave treatment is 10s-120s.

9. A negative electrode sheet, characterized in that: The invention comprises the mixed conductive polymer-coated tin-carbon negative electrode material according to any one of claims 1 to 3, or the mixed conductive polymer-coated tin-carbon negative electrode material prepared by the preparation method according to any one of claims 4 to 8.

10. A sodium ion battery, characterized in that: Including the negative electrode sheet according to claim 9.

11. An electrical equipment, characterized in that: Including the sodium ion battery according to claim 10.

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