Photo-assisted catalytic composite sodium supplement, preparation method and sodium ion battery

Abstract

The invention relates to a photo-assisted catalytic composite sodium supplementing agent, a preparation method thereof and a sodium ion battery, and the preparation method of the photo-assisted catalytic composite sodium supplementing agent comprises the following steps: performing liquid phase mixing on sodium squarate and a nano semiconductor material to obtain mixed slurry, and performing sanding and spray drying on the mixed slurry to obtain the photo-assisted catalytic composite sodium supplementing agent. The nano semiconductor material introduced into the composite sodium supplementing agent obtained by the preparation method provided by the invention can reduce the sodium removal energy barrier of sodium squarate, so that the sodium removal voltage of the composite sodium supplementing agent is reduced, and the utilization efficiency of the composite sodium supplementing agent is effectively improved. In the first charging process of the battery, visible light is introduced for assistance, so that the catalytic performance can be further improved, the sodium removal energy barrier of the sodium squarate is reduced, the sodium removal voltage of the composite sodium supplementing agent is further reduced, and the utilization efficiency of the sodium squarate is further improved.

Description

Technical Field

[0001] The present disclosure relates to the field of battery manufacturing technology, and in particular to a light-assisted catalytic composite sodium supplement and a preparation method thereof, and a sodium ion battery, in particular to a light-assisted catalytic composite sodium supplement and a preparation method thereof, a sodium ion battery and a use method thereof. Background Art

[0002] With the development of battery technology, the use of sodium-ion batteries has attracted more and more attention. However, during the first charging process, sodium-ion batteries have the same disadvantages as lithium-ion batteries. They will irreversibly form a stable solid electrolyte interface (SEI) film on the surface of the negative electrode. Although the SEI film can effectively transfer sodium ions while effectively isolating the entry of electrolyte and maintaining the stability of battery operation, its formation process is accompanied by a large amount of irreversible loss of active sodium, resulting in a decrease in coulombic efficiency. Therefore, it is urgent to explore appropriate pre-sodiumization methods to compensate for the irreversible loss of active sodium in the first cycle.

[0003] At present, the sodium replenishment methods are divided into positive electrode sodium replenishment method, negative electrode sodium replenishment method and diaphragm sodium replenishment method. The positive electrode sodium replenishment method is simple to operate and has a good sodium replenishment effect, and has a better development prospect. At present, the positive electrode sodium replenishers used more in the industry include sodium carbonate, sodium oxalate and sodium squarate, but these sodium replenishers each have some problems, which make them unable to be applied industrially. For example, the actual capacity of sodium carbonate is small; the initial sodium removal voltage of sodium oxalate is too high (4.2V), which is higher than the working voltage of sodium ion batteries (generally <3.8V); although the initial sodium removal voltage of sodium squarate (3.7V) is suitable for the working voltage of sodium ion batteries, its complete decomposition requires a voltage of about 4.0V, and the capacity that can be exerted within the maximum working voltage range of sodium ion batteries (<3.8V) is small, and the sodium replenishment effect is not good. That is, the high sodium removal voltage of the sodium replenisher has always been a problem restricting the industrialization of the sodium replenisher. Summary of the invention

[0004] In order to solve the above technical problems, the present disclosure provides a light-assisted catalytic composite sodium supplement and a preparation method thereof, and a sodium ion battery.

[0005] In a first aspect, the present disclosure provides a method for preparing a light-assisted catalytic composite sodium supplement, the preparation method comprising the following steps:

[0006] Sodium squarate and nano-semiconductor materials are mixed in liquid phase to obtain a mixed slurry, and the mixed slurry is sand-milled and spray-dried to obtain the light-assisted catalytic composite sodium supplement agent.

[0007] As a preferred technical solution of the present disclosure, the nano-semiconductor material is selected from titanium dioxide (TiO2).

[0008] As a preferred technical solution of the present disclosure, the mass ratio of the sodium squarate and the nano-semiconductor material is (90-95):(5-10).

[0009] As a preferred technical solution of the present disclosure, based on the sum of the mass of the sodium squarate and the nano-semiconductor material being 100%, the addition amount of the sodium squarate is 90-95%.

[0010] As a preferred technical solution of the present disclosure, the sanding time is 120-540 minutes.

[0011] As a preferred technical solution of the present disclosure, after the sand grinding, the D50 of the slurry is 100-500nm.

[0012] As a preferred technical solution of the present disclosure, the spray drying temperature is 120-200°C.

[0013] As a preferred technical solution of the present disclosure, the spray drying time is 6-24 hours.

[0014] As a preferred technical solution of the present disclosure, the mixed slurry also includes a dispersant.

[0015] As a preferred technical solution of the present disclosure, the added amount of the dispersant is 0.5-1% of the mass of the nano-semiconductor material.

[0016] As a preferred technical solution of the present disclosure, the dispersant includes any one of polyvinyl pyrrolidone, polyethylene glycol or polyacrylic acid, or a combination of at least two thereof.

[0017] As a preferred technical solution of the present disclosure, the preparation method comprises:

[0018] (1) mixing sodium squarate and a dispersant in water to obtain a saturated aqueous solution;

[0019] (2) dispersing the nano-semiconductor material in the saturated aqueous solution to obtain a mixed slurry;

[0020] (3) The mixed slurry is sand-milled and spray-dried to obtain the light-assisted catalytic composite sodium supplement agent.

[0021] In a second aspect, the present disclosure provides a photo-assisted catalytic composite sodium supplement prepared using the preparation method described in the first aspect.

[0022] In a third aspect, the present disclosure provides an application of the light-assisted catalytic composite sodium supplement described in the second aspect in a sodium ion battery, preferably in a positive electrode plate of a sodium ion battery.

[0023] In a fourth aspect, the present disclosure provides a positive electrode plate, comprising a positive electrode active material and the light-assisted catalytic composite sodium supplement agent described in the second aspect.

[0024] As a preferred technical solution of the present disclosure, the added amount of the photo-assisted catalytic composite sodium supplement is 0.5-10% of the positive electrode active material.

[0025] As a preferred technical solution of the present disclosure, the positive electrode active material is selected from any one of sodium ferric pyrosulfate phosphate, sodium vanadium phosphate or sodium ferrite, or a combination of at least two thereof.

[0026] As a preferred technical solution of the present disclosure, the positive electrode current collector used in the positive electrode plate is a transparent conductive oxide (TCO) film.

[0027] In a fifth aspect, the present disclosure provides a sodium ion battery, comprising the positive electrode sheet described in the fourth aspect.

[0028] As a preferred technical solution of the present disclosure, the shell of the sodium ion battery is a shell made of a light-transmitting material.

[0029] In a sixth aspect, the present disclosure provides a method for using the sodium ion battery described in the fifth aspect, the method for using the sodium ion battery comprising: during the first charging process of the sodium ion battery, using a visible light source for full irradiation.

[0030] As a preferred technical solution of the present disclosure, the visible light source is a xenon lamp.

[0031] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0032] (1) The nano-semiconductor material introduced into the composite sodium supplement agent obtained by the preparation method provided by the present disclosure can reduce the sodium removal energy barrier of sodium squarate, thereby reducing the sodium removal voltage of the composite sodium supplement agent, and effectively improving the utilization efficiency of the composite sodium supplement agent;

[0033] (2) Introducing visible light assistance during the first charging process of sodium-ion batteries can further improve their catalytic performance, reduce the energy barrier for the desodiumization of sodium squarate, and thereby reduce the desodiumization voltage of the composite sodium supplement, thereby further improving the utilization efficiency of sodium squarate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0036] Figure 1 The present invention is a flow chart for preparing the light-assisted catalytic composite sodium supplement agent;

[0037] Figure 2 This is the EDS image of the photocatalytically assisted composite sodium supplement prepared in Example 1;

[0038] Figure 3 Charging curves of half-cells provided for Application Example 1 and Comparative Application Examples 1-2;

[0039] Figure 4 The charge and discharge curves of the sodium ion battery provided for Application Example 5 and Comparative Application Examples 3-5;

[0040] Figure 5 The cycle energy retention rate curve of the sodium ion battery provided for Application Example 5 and Comparative Application Example 5. DETAILED DESCRIPTION

[0041] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0042] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0043] In the current existing technology, the positive electrode sodium supplement method has a good development prospect. However, the high sodium removal voltage of the sodium supplement agent has always been a problem that restricts the industrialization of the sodium supplement agent. In order to solve this problem, the present invention provides a photocatalytic assisted composite sodium supplement agent and a preparation method thereof, a sodium ion battery containing the same and a method for using the sodium ion battery.

[0044] In a first aspect, the present disclosure provides a method for preparing a light-assisted catalytic composite sodium supplement, the preparation method comprising the following steps:

[0045] Sodium squarate and nano-semiconductor materials are mixed in liquid phase to obtain a mixed slurry, and the mixed slurry is sand-milled and spray-dried to obtain the light-assisted catalytic composite sodium supplement agent.

[0046] In the preparation method provided by the present disclosure, nano-semiconductor materials are introduced into the composite sodium supplement agent, which, as insoluble nano-particles, can provide nucleation sites for sodium squarate. Therefore, during the spray drying process, sodium squarate can grow on the surface of the nano-semiconductor material when precipitated from the liquid solution, that is, the sodium squarate and the nano-semiconductor material are uniformly dispersed to form a composite sodium supplement agent. Therefore, the composite sodium supplement agent has a stable structure and uniform composition, and has an excellent sodium supplement effect.

[0047] Moreover, nano-semiconductor materials are introduced into the composite sodium supplement. Nano-semiconductor materials have efficient conductivity and catalytic effects, which can reduce the desodiumation energy barrier of sodium squarate, thereby reducing the desodiumation voltage of the composite sodium supplement, and effectively improving the utilization efficiency of the composite sodium supplement.

[0048] Furthermore, since the nano-semiconductor material has semiconductor properties, it can further improve its catalytic performance with the assistance of visible light. Therefore, the composite sodium supplementer obtained in the present invention is a light-assisted catalytic composite sodium supplementer, which can further reduce the desodiumation energy barrier of sodium squarate with the assistance of visible light, further reduce the desodiumation voltage of the composite sodium supplementer, and further improve the utilization efficiency of the composite sodium supplementer.

[0049] Therefore, the composite sodium supplement prepared by the preparation method provided by the present disclosure is applied to sodium ion batteries, which can effectively improve the comprehensive performance of the battery and reduce the cost of the sodium ion battery.

[0050] The composite sodium supplement provided by the present invention has a simple preparation process and small fluctuation of process parameters. The composite sodium supplement finally obtained has uniform composition and stable structure, and has obvious catalytic effect and can be produced in large quantities.

[0051] As a preferred technical solution of the present disclosure, the nano-semiconductor material is TiO2.

[0052] As a preferred technical solution of the present disclosure, the mass ratio of the sodium squarate and the nano-semiconductor material is (90-95):(5-10), for example, 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, etc.

[0053] As a preferred technical solution of the present disclosure, based on the sum of the mass of the sodium squarate and the nano-semiconductor material being 100%, the addition amount of the sodium squarate is 90-95%, for example, 90%, 91%, 92%, 93%, 94%, 95%, etc.

[0054] As a preferred technical solution of the present invention, the sanding time is 120-540 min, for example, 120 min, 150 min, 180 min, 200 min, 260 min, 300 min, 380 min, 400 min, 490 min, 540 min, etc.

[0055] As a preferred technical solution of the present disclosure, after the sand grinding, the D50 of the slurry is 100-500nm, for example, 100nm, 120nm, 150nm, 180nm, 200nm, 240nm, 290nm, 350nm, 400nm, 480nm, 500nm, etc.

[0056] As a preferred technical solution of the present disclosure, the spray drying temperature is 120-200°C, for example, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, etc.

[0057] As a preferred technical solution of the present disclosure, the spray drying time is 6-24 h, for example, 6 h, 8 h, 10 h, 13 h, 16 h, 18 h, 19 h, 20 h, 22 h, 24 h, etc.

[0058] As a preferred technical solution of the present disclosure, the mixed slurry also includes a dispersant.

[0059] As a preferred technical solution of the present disclosure, the added amount of the dispersant is 0.5-1% of the mass of the nano-semiconductor material, for example, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.

[0060] As a preferred technical solution of the present disclosure, the dispersant includes any one of polyvinyl pyrrolidone, polyethylene glycol or polyacrylic acid, or a combination of at least two thereof.

[0061] As a preferred technical solution of the present disclosure, Figure 1 As shown, the preparation method comprises:

[0062] (1) mixing sodium squarate and a dispersant in water to obtain a saturated aqueous solution;

[0063] (2) dispersing the nano-semiconductor material in the saturated aqueous solution to obtain a mixed slurry;

[0064] (3) The mixed slurry is sand-milled and spray-dried to obtain the light-assisted catalytic composite sodium supplement agent.

[0065] In a second aspect, the present disclosure provides a photo-assisted catalytic composite sodium supplement prepared using the preparation method described in the first aspect.

[0066] The sodium squarate included in the composite sodium supplement prepared by the preparation method provided by the present disclosure is uniformly and closely combined with the nano semiconductor material, the active component particle size is small, and it has an excellent sodium supplement effect. It is added to the positive electrode material of the sodium ion battery, coated on the light-transmitting positive electrode current collector, and combined with a transparent shell, it can use visible light to assist in improving the catalytic performance of the nano semiconductor material, and exert high discharge capacity and high cycle performance.

[0067] The composite sodium supplement provided by the present invention has a low sodium desorption voltage and high flux in sodium ion batteries, and can be applied to the positive electrode plates of different sodium ion batteries such as layered oxygen and polyanion, thus contributing to the industrial development of positive electrode materials for sodium ion batteries.

[0068] In a third aspect, the present disclosure provides an application of the light-assisted catalytic composite sodium supplement described in the second aspect in a sodium ion battery, preferably in a positive electrode plate of a sodium ion battery.

[0069] In a fourth aspect, the present disclosure provides a positive electrode plate, comprising a positive electrode active material and the light-assisted catalytic composite sodium supplement agent described in the second aspect.

[0070] The light-assisted catalytic composite sodium supplement disclosed in the present invention is mixed with a positive electrode material to form a positive electrode slurry, which is coated on a light-transmitting, highly conductive TCO film as a positive electrode plate, and a light-transmitting acrylic material is selected as a battery shell, which can introduce visible light to assist in improving the catalytic performance of the nano-semiconductor material and give full play to the advantage of the low decomposition voltage of the composite sodium supplement.

[0071] As a preferred technical solution of the present disclosure, the addition amount of the light-assisted catalytic composite sodium supplement is 0.5-10% of the positive electrode active material, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc.

[0072] As a preferred technical solution of the present disclosure, the positive electrode active material is selected from any one of sodium ferric pyrosulfate phosphate (NFPP), sodium vanadium phosphate (NVP) or sodium ferrite (NFO) or a combination of at least two thereof.

[0073] As a preferred technical solution of the present disclosure, the positive electrode current collector used in the positive electrode plate is a TCO (Transparent Conductive Oxides) film.

[0074] The composite sodium supplementer provided by the present disclosure is a light-assisted composite sodium supplementer, in which the active ingredient has a small particle size and is assembled into a battery with a light-transmitting and highly conductive TCO current collector and an acrylic light-transmitting positive electrode shell. During the first charging process of the battery, visible light is introduced to assist in improving the catalytic performance of the nano-semiconductor material, which can further improve the cycle performance of the sodium ion battery and reduce the decomposition potential. That is, the composite sodium supplementer provided by the present disclosure has a very excellent sodium supplement effect.

[0075] In a fifth aspect, the present disclosure provides a sodium ion battery, comprising the positive electrode sheet described in the fourth aspect.

[0076] As a preferred technical solution of the present disclosure, the shell of the sodium ion battery is a shell made of a light-transmitting material, and preferably the shell is a shell made of a light-transmitting acrylic material.

[0077] As a preferred technical solution of the present disclosure, the sodium ion battery is a button battery.

[0078] In a sixth aspect, the present disclosure provides a method for using the sodium ion battery described in the fifth aspect, the method for using the sodium ion battery comprising: during the first charging process of the sodium ion battery, using a visible light source for full irradiation.

[0079] As a preferred technical solution of the present disclosure, the visible light source is a xenon lamp.

[0080] As a preferred technical solution of the present disclosure, the sodium ion battery uses a xenon lamp to irradiate the positive electrode surface of the battery during the first charging process.

[0081] The light-assisted catalytic composite sodium supplement agent disclosed in the present invention includes a nano-semiconductor material, which has semiconductor properties. The introduction of visible light assistance during the first charging process of the battery can further improve the catalytic performance of the nano-semiconductor material, further reduce the de-sodium energy barrier of sodium squarate, and then reduce the de-sodium voltage of the composite sodium supplement material, so that the utilization efficiency of sodium squarate is further improved. Applying this photocatalytic assisted composite sodium supplement agent to sodium ion batteries can effectively improve the comprehensive performance of sodium ion batteries and reduce costs.

[0082] The following is an explanation through specific embodiments.

[0083] Example 1

[0084] This embodiment provides a photo-assisted catalytic composite sodium supplement, and the preparation method is as follows:

[0085] (1) Sodium squarate and a dispersant are mixed in water to obtain a saturated aqueous solution, wherein:

[0086] The dispersant is pyrrolidone, and the added amount is 1.0% of the mass of the nano-semiconductor material;

[0087] (2) The nano-semiconductor material is dispersed in the saturated aqueous solution to obtain a mixed slurry, wherein:

[0088] The nano-semiconductor material is nano-TiO2, and the mass ratio of sodium squarate to nano-TiO2 material is 95:5;

[0089] (3) The mixed slurry is sand-milled for 120 minutes to obtain a mixed slurry with a slurry particle size D50 of about 200 nm, and then spray-dried at 150° C. to obtain the photo-assisted catalytic composite sodium supplement.

[0090] Performance Test 1

[0091] The light-assisted catalytic composite sodium supplement obtained in Example 1 was subjected to EDS analysis, and the results were as follows:

[0092] Figure 2 This is the EDS graph of the photocatalytically assisted composite sodium supplement prepared in Example 1. It can be seen from the figure that the composite sodium supplement obtained in the present disclosure includes nano-semiconductor materials and sodium squarate, and has a stable structure and the two are evenly distributed.

[0093] Example 2

[0094] This embodiment provides a photo-assisted catalytic composite sodium supplement, and the preparation method is as follows:

[0095] (1) Sodium squarate and a dispersant are mixed in water to obtain a saturated aqueous solution, wherein:

[0096] The dispersant is polyethylene glycol, and the added amount is 0.50% of the mass of the nano-semiconductor material;

[0097] (2) The nano-semiconductor material is dispersed in the saturated aqueous solution to obtain a mixed slurry, wherein:

[0098] The nano semiconductor material is nano TiO2, and the mass ratio of sodium squarate to nano TiO2 is 90:10;

[0099] (3) The mixed slurry is sand-milled for 240 minutes to obtain a mixed slurry with a slurry particle size D50 of about 150 nm, and then spray-dried at 180° C. to obtain the photo-assisted catalytic composite sodium supplement agent.

[0100] Example 3

[0101] This embodiment provides a photo-assisted catalytic composite sodium supplement, and the preparation method is as follows:

[0102] (1) Sodium squarate and a dispersant are mixed in water to obtain a saturated aqueous solution, wherein:

[0103] The dispersant is polyvinyl pyrrolidone, and the added amount is 0.75% of the mass of the nano-semiconductor material;

[0104] (2) The nano-semiconductor material is dispersed in the saturated aqueous solution to obtain a mixed slurry, wherein:

[0105] The nano-semiconductor material is nano-TiO2, and the mass ratio of sodium squarate to nano-TiO2 material is 93:7;

[0106] (3) The mixed slurry is sand-milled for 300 minutes to obtain a mixed slurry with a slurry particle size D50 of about 140 nm, and then spray-dried at 160° C. to obtain the photo-assisted catalytic composite sodium supplement.

[0107] Example 4

[0108] This embodiment provides a photo-assisted catalytic composite sodium supplement, and the preparation method is as follows:

[0109] (1) Sodium squarate and a dispersant are mixed in water to obtain a saturated aqueous solution, wherein:

[0110] The dispersant is polyacrylic acid, and the added amount is 0.90% of the mass of the nano-semiconductor material;

[0111] (2) The nano-semiconductor material is dispersed in the saturated aqueous solution to obtain a mixed slurry, wherein:

[0112] The nano-semiconductor material is nano-TiO2, and the mass ratio of sodium squarate to nano-TiO2 material is 92:8;

[0113] (3) The mixed slurry is sand-milled for 540 minutes to obtain a mixed slurry with a slurry particle size D50 of about 100 nm, and then spray-dried at 200° C. to obtain the photo-assisted catalytic composite sodium supplement.

[0114] Comparative Example 1

[0115] This comparative example provides a sodium supplement, and the preparation method is as follows:

[0116] The difference from Example 1 is that in the preparation method of this comparative example, no nano-semiconductor material is added, and the preparation method is as follows:

[0117] (1) preparing sodium squarate into a saturated aqueous solution;

[0118] (2) The saturated aqueous solution was sand-milled for 120 min and then spray-dried at 150° C. to obtain a sodium squarate sodium supplement.

[0119] Application Examples 1-4

[0120] This application example provides a half-battery and a method of use, as follows:

[0121] (1) 80% of the photo-assisted catalytic composite sodium supplement agent (provided in Examples 1-4), 10% of Super P, and 10% of PVDF were mixed with NMP, and a TCO film was used as a positive electrode current collector to obtain a composite sodium supplement material electrode sheet by homogenization, coating, drying, and rolling;

[0122] (2) Using a sodium metal sheet as the counter electrode, adding 5 vol% fluoroethylene carbonate to a 1 M NaClO4 / propylene carbonate solution as the electrolyte, glass fiber as the separator, and using an acrylic light-transmitting positive electrode shell, the button cell was assembled in a high-purity argon atmosphere glove box;

[0123] (3) The charging test was performed in the voltage window of 2.7-4.2 V, and the positive electrode surface was irradiated with a xenon lamp throughout the first cycle of charging.

[0124] Comparative application example 1

[0125] This comparative application example provides a half-battery and a method of use.

[0126] The difference from Application Example 1 is that in this comparative application example, the sodium supplementer is the sodium supplementer (sodium squarate) provided in Comparative Example 1.

[0127] Comparative Application Example 2

[0128] This comparative application example provides a half-battery and a method of use.

[0129] The difference from Application Example 1 is that in this comparative application example, no xenon lamp irradiation is used.

[0130] Performance Test 2

[0131] The electrochemical performance test of the half-cell provided in Example 1-4 and Comparative Application Example 1-2 was carried out, and the charging test was carried out in the voltage window of 2.7-4.2V. The results are shown in Figure 3 and Table 1:

[0132] Figure 3 The charging curves of the half-cells provided for Application Example 1 and Comparative Application Examples 1-2 show that the composite sodium supplement provided by the present disclosure has the lowest initial decomposition voltage, which is around 3.5V, and the lowest complete decomposition voltage, which is around 3.75V.

[0133] The test results are shown in Table 1:

[0134] Table 1

[0135] sample Compound sodium supplement Initial decomposition voltage / V Complete decomposition voltage / V Application Example 1 Example 1 3.50 3.75 Application Example 2 Example 2 3.55 3.80 Application Example 3 Example 3 3.58 3.82 Application Example 4 Example 4 3.56 3.77 Comparative application example 1 Comparative Example 1 3.72 3.98 Comparative Application Example 2 Example 1 3.60 3.86

[0136] It can be seen from Table 1 that the composite sodium supplement provided by the present disclosure has a lower initial sodium removal voltage and a complete decomposition voltage, and the decomposition voltage of the composite sodium supplement can be further reduced by using visible light irradiation during the first charging process.

[0137] Application Example 5

[0138] This application example provides a sodium ion battery and a method of use, as follows:

[0139] (1) Sodium ferric pyrophosphate (NFPP), Super P, and PVDF were mixed in a mass ratio of 8:1:1, and a composite sodium supplement of 2.5% by mass of NFPP was added, and the above mixture was mixed with NMP, and a TCO film was used as a positive electrode current collector, and a positive electrode sheet of NFPP was obtained by homogenization, coating, drying, and rolling;

[0140] (2) Using commercial hard carbon to prepare the negative electrode;

[0141] (3) 5 Vol% fluoroethylene carbonate was added to a 1 M NaClO4 / propylene carbonate solution as an electrolyte, glass fiber was used as a separator, and an acrylic light-transmitting positive electrode shell was selected to assemble the button cell in a high-purity argon atmosphere glove box.

[0142] The method of use is: during the first cycle of charging, apply xenon lamp to the positive electrode surface throughout the whole process.

[0143] Application Examples 6-8

[0144] This application example provides a sodium ion battery and a method of use.

[0145] The difference from Application Example 1 is that in this application example:

[0146] The positive electrode material is NFPP, and the composite sodium supplement provided in Example 2 is used, and the addition amount is 5% (Application Example 6);

[0147] The positive electrode material is NVP, and the composite sodium supplement provided in Example 3 is used, and the addition amount is 7.5% (Application Example 7);

[0148] The positive electrode material is NFO, and the composite sodium supplement provided in Example 4 is used, with an addition amount of 10% (Application Example 8).

[0149] Comparative Application Example 3

[0150] This comparative application example provides a sodium ion battery and a method of use.

[0151] The difference from Application Example 5 is that in this comparative application example, the sodium supplementer is the sodium squarate supplementer provided in Comparative Example 1.

[0152] Comparative Application Example 4

[0153] This comparative application example provides a sodium ion battery and a method of use.

[0154] The difference from Application Example 5 is that in this comparative application example, no xenon lamp irradiation is used.

[0155] Comparative Application Example 5

[0156] This comparative application example provides a sodium ion battery and a method of use.

[0157] The difference from Application Example 5 is that in this comparative application example, no xenon lamp irradiation is used and no sodium supplement is added.

[0158] Performance Test 3

[0159] The sodium ion batteries provided in the corresponding use cases 5-8 and comparative application examples 3-5 were tested for the first cycle charge and discharge at a current of 0.1C. The corresponding use case 5 and comparative application example 5 were tested for 250 cycles of charge and discharge at a current of 0.1C. The voltage window was 1.8-4.2V. The results are shown in Figure 4-5 and Table 2:

[0160] Figure 4 The charge and discharge curves of the sodium ion battery provided in Application Example 5 (the composite catalyst provided in Example 1) and Comparative Application Examples 3-5 show that the sodium ion battery using the composite sodium supplement provided in the present invention has the highest charge and discharge specific capacity.

[0161] Figure 5 The cycle energy retention rate curve diagram of the sodium ion battery provided for Application Example 5 (the composite catalyst provided in Example 1) and Comparative Application Example 5 (blank control) shows that the cycle retention rate of the sodium ion battery using the composite sodium supplement provided by the present invention is the highest.

[0162] The test results are shown in Table 2:

[0163] Table 2

[0164]

[0165] Note: Cycle energy retention rate is the retention rate after 150 cycles.

[0166] It can be seen from Table 2 that the comprehensive performance of the sodium ion battery obtained by using the composite sodium supplement provided by the present disclosure is the best.

[0167] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0168] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a light-assisted catalytic composite sodium supplement, characterized in that: The preparation method comprises: Sodium squarate and nano-semiconductor materials are mixed in liquid phase to obtain a mixed slurry, and the mixed slurry is sand-milled and spray-dried to obtain the light-assisted catalytic composite sodium supplement agent.

2. The preparation method according to claim 1, characterized in that: The nano semiconductor material is selected from TiO2; And / or, the mass ratio of the sodium squarate and the nano-semiconductor material is (90-95):(5-10); And / or, based on the sum of the mass of the sodium squarate and the nano-semiconductor material being 100%, the addition amount of the sodium squarate is 90-95%.

3. The preparation method according to claim 1 or 2, characterized in that: The sanding time is 120-540min; and / or, after the sand milling, the D50 of the slurry is 100-500 nm; And / or, the spray drying temperature is 120-200°C; And / or, the spray drying time is 6-24h.

4. The preparation method according to any one of claims 1 to 3, characterized in that The mixed slurry also includes a dispersant; Preferably, the added amount of the dispersant is 0.5-1% of the mass of the nano-semiconductor material; Preferably, the dispersant includes any one of pyrrolidone, polyethylene glycol or polyacrylic acid, or a combination of at least two thereof.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The preparation method comprises: (1) mixing sodium squarate and a dispersant in water to obtain a saturated aqueous solution; (2) dispersing the nano-semiconductor material in the saturated aqueous solution to obtain a mixed slurry; (3) The mixed slurry is sand-milled and spray-dried to obtain the light-assisted catalytic composite sodium supplement agent.

6. A photo-assisted catalytic composite sodium supplement prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the light-assisted catalytic composite sodium supplement according to claim 6 in a sodium ion battery, preferably in a positive electrode of a sodium ion battery.

8. A positive electrode sheet, characterized in that: It comprises a positive electrode active material and the light-assisted catalytic composite sodium supplement agent according to claim 6; Preferably, the amount of the photo-assisted catalytic composite sodium supplement added is 0.5-10% of the positive electrode active material; Preferably, the positive electrode active material is selected from any one or a combination of at least two of sodium pyrosulfate iron phosphate, sodium vanadium phosphate or sodium ferrite; Preferably, the positive electrode current collector used in the positive electrode plate is a TCO film.

9. A sodium ion battery, characterized in that: Including the positive electrode sheet according to claim 8; Preferably, the shell of the sodium ion battery is a shell made of a light-transmitting material.

10. A method for using the sodium ion battery according to claim 9, characterized in that: The method of use comprises: during the first charging process of the sodium ion battery, the battery is irradiated with a visible light source throughout the entire process; Preferably, the visible light source is a xenon lamp.

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