Sodium battery negative electrode material and preparation method thereof

Abstract

The invention discloses a sodium battery negative electrode material preparation method, which comprises: 1, crushing walnut shells to a particle size of 10 m, and carrying out carbonization treatment at a temperature of 1200 DEG C for 2 h to obtain hard carbon particles; and 2, firstly adding the hard carbon particles into a sufficient amount of modification liquid, stirring and modifying, and after stirring, carrying out suction filtration and drying to obtain the modified hard carbon body. According to the sodium battery negative electrode material disclosed by the invention, the hard carbon particles are subjected to stirring modification treatment through the modification liquid and are matched with the ball-milling agent for ball-milling improvement, and through coordination and synergism of the hard carbon particles and the ball-milling agent, the capacity retention rate performance of a product is excellent, the cycling stability effect is remarkable, and meanwhile, the discharge capacity of the product is obviously improved under a high-rate condition; the modified liquid is prepared by preheating a carbon nano tube, blending and ball-milling with a lanthanum chloride solution and diatomite, and then carrying out hot calcination treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of negative electrode materials, and in particular to a negative electrode material for a sodium battery and a preparation method thereof. Background Art

[0002] With the continuous development of new energy technology, sodium ion batteries have attracted much attention. With the continuous development of sodium ion battery technology and the reduction of costs, commercial applications and research are becoming more and more extensive. The existing negative electrode materials have poor capacity retention performance and poor cycle stability under multiple cycle conditions. At the same time, the discharge capacity of the product decreases significantly under high rate conditions, which limits the efficiency of product use. Based on this, the present invention further improves it. Summary of the invention

[0003] In view of the defects of the prior art, the object of the present invention is to provide a sodium battery negative electrode material and a preparation method thereof to solve the problems raised in the above background technology.

[0004] The present invention solves the technical problem by adopting the following technical solution: The present invention provides a method for preparing a negative electrode material for a sodium battery, comprising the following steps: Step 1: crush the walnut shell to 10µm and then carbonize it at 1200℃ for 2h to obtain hard carbon particles; Step 2: adding the hard carbon particles into a sufficient amount of the modification liquid and stirring for modification treatment, filtering and drying after the stirring is completed to obtain a modified hard carbon body; Step 3: Mix the modified hard carbon and the ball milling agent in a weight ratio of 5:3 and perform ball milling at a ball milling speed of 1000 r / min for 1 hour. After the ball milling is completed, filter and dry to obtain the sodium battery negative electrode material.

[0005] Preferably, the stirring speed of the stirring modification treatment is 750-850 r / min, and the stirring is for 1 hour.

[0006] Preferably, the preparation method of the modified liquid is: S1: preheating the carbon nanotubes at 70-75°C for 1 hour, then mixing and ball-milling 4-7 parts of the preheated carbon nanotubes, 2-3 parts of lanthanum chloride solution, and 1-2 parts of diatomaceous earth at a ball-milling speed of 1500 r / min for 2 hours, filtering and drying after the ball-milling is completed; S2: The S1 product is calcined at 220-230°C for 1 hour, then cooled to 65°C at a rate of 1-3°C / min and kept warm to obtain a modified filler; S3: 4-7 parts of modified filler and 2-3 parts of silane coupling agent are added to 5-8 parts of sodium dodecyl sulfate solution, and then 1-2 parts of sodium carboxymethyl cellulose are added and stirred to obtain a modified solution; Preferably, the silane coupling agent is silane coupling agent KH560; and the mass fraction of the sodium dodecyl sulfate solution is 2-5%.

[0007] Preferably, the mass fraction of the lanthanum chloride solution is 2-5%.

[0008] Preferably, the preparation method of the ball mill is: S11: irradiating the nano zinc oxide in a proton irradiation box for 1 hour at an irradiation power of 350 W, and obtaining irradiated nano zinc oxide after the irradiation is completed; S12: 1-2 parts of nano-silica sol, 5-7 parts of sodium lignin sulfonate solution, 3-5 parts of nano-titanium dioxide and 2-3 parts of yttrium oxide are stirred to obtain a ball milling solution; S13: The irradiated nano zinc oxide is immersed in a ball milling solution of 3-5 times the total amount of the irradiated nano zinc oxide, and then ultrasonically treated. After the immersion is completed, a ball mill is obtained.

[0009] Preferably, the mass fraction of the sodium lignin sulfonate solution is 2-5%.

[0010] Preferably, the ultrasonic power of the immersion ultrasonic treatment is 450-500W, and the ultrasonic treatment is performed for 1 hour.

[0011] The invention also provides a sodium battery negative electrode material prepared by a method for preparing a sodium battery negative electrode material.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The sodium battery negative electrode material of the present invention adopts hard carbon particles, which are subjected to a modification treatment by stirring with a modification liquid, and then improved by ball milling with a ball milling agent. Through the coordinated synergy of the two, the product has excellent capacity retention rate performance and remarkable cycle stability effect, and the discharge capacity of the product is significantly improved under high rate conditions; the modification liquid is preheated with carbon nanotubes, and then improved by blending with lanthanum chloride solution and diatomaceous earth, and then heat calcined, and a modification liquid improvement system is obtained by coordination with a silane coupling agent and a sodium dodecyl sulfate solution to optimize product performance effects; the nano zinc oxide in the ball milling agent is treated with proton irradiation, and then nano silica sol, sodium lignin sulfonate solution, nano titanium dioxide and yttrium oxide are blended to obtain a ball milling liquid, and the ball milling improvement of the ball milling liquid and the synergy between the raw materials are achieved, so that the system performance is further improved. DETAILED DESCRIPTION

[0013] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] The method for preparing a negative electrode material for a sodium battery of the present embodiment comprises the following steps: Step 1: crush the walnut shell to 10µm and then carbonize it at 1200℃ for 2h to obtain hard carbon particles; Step 2: adding the hard carbon particles into a sufficient amount of the modification liquid and stirring for modification treatment, filtering and drying after the stirring is completed to obtain a modified hard carbon body; Step 3: Mix the modified hard carbon and the ball milling agent in a weight ratio of 5:3 and perform ball milling at a ball milling speed of 1000 r / min for 1 hour. After the ball milling is completed, filter and dry to obtain the sodium battery negative electrode material.

[0015] The stirring speed of the stirring modification treatment in this embodiment is 750-850 r / min, and the stirring is for 1 hour.

[0016] The preparation method of the modified liquid of this embodiment is: S1: preheating the carbon nanotubes at 70-75°C for 1 hour, then mixing and ball-milling 4-7 parts of the preheated carbon nanotubes, 2-3 parts of lanthanum chloride solution, and 1-2 parts of diatomaceous earth at a ball-milling speed of 1500 r / min for 2 hours, filtering and drying after the ball-milling is completed; S2: The S1 product is calcined at 220-230°C for 1 hour, then cooled to 65°C at a rate of 1-3°C / min and kept warm to obtain a modified filler; S3: 4-7 parts of modified filler and 2-3 parts of silane coupling agent are added to 5-8 parts of sodium dodecyl sulfate solution, and then 1-2 parts of sodium carboxymethyl cellulose are added and stirred to obtain a modified solution; The silane coupling agent of this embodiment is silane coupling agent KH560; the mass fraction of the sodium dodecyl sulfate solution is 2-5%.

[0017] The mass fraction of the lanthanum chloride solution of the present embodiment is 2-5%.

[0018] The preparation method of the ball mill of this embodiment is: S11: irradiating the nano zinc oxide in a proton irradiation box for 1 hour at an irradiation power of 350 W, and obtaining irradiated nano zinc oxide after the irradiation is completed; S12: 1-2 parts of nano-silica sol, 5-7 parts of sodium lignin sulfonate solution, 3-5 parts of nano-titanium dioxide and 2-3 parts of yttrium oxide are stirred to obtain a ball milling solution; S13: The irradiated nano zinc oxide is immersed in a ball milling solution of 3-5 times the total amount of the irradiated nano zinc oxide, and then ultrasonically treated. After the immersion is completed, a ball mill is obtained.

[0019] The mass fraction of the sodium lignin sulfonate solution in this embodiment is 2-5%.

[0020] The ultrasonic power of the immersion ultrasonic treatment in this embodiment is 450-500W, and the ultrasonic treatment is performed for 1 hour.

[0021] The sodium battery negative electrode material is prepared by a method for preparing a sodium battery negative electrode material in this embodiment.

[0022] Example 1. The method for preparing a negative electrode material for a sodium battery of the present embodiment comprises the following steps: Step 1: crush the walnut shell to 10µm and then carbonize it at 1200℃ for 2h to obtain hard carbon particles; Step 2: adding the hard carbon particles into a sufficient amount of the modification liquid and stirring for modification treatment, filtering and drying after the stirring is completed to obtain a modified hard carbon body; Step 3: Mix the modified hard carbon and the ball milling agent in a weight ratio of 5:3 and perform ball milling at a ball milling speed of 1000 r / min for 1 hour. After the ball milling is completed, filter and dry to obtain the sodium battery negative electrode material.

[0023] The stirring speed of the stirring modification treatment in this embodiment is 750 r / min, and the stirring is for 1 hour.

[0024] The preparation method of the modified liquid of this embodiment is: S1: preheat the carbon nanotubes at 70°C for 1 h, then mix and ball-mill 4 parts of the preheated carbon nanotubes, 2 parts of lanthanum chloride solution and 1 part of diatomaceous earth at a ball-milling speed of 1500 r / min for 2 h. After the ball-milling is completed, filter and dry; S2: The product of S1 was calcined at 220°C for 1 h, then cooled to 65°C at a rate of 1°C / min and kept warm to obtain a modified filler; S3: 4 parts of modified filler and 2 parts of silane coupling agent are added to 5 parts of sodium dodecyl sulfate solution, and then 1 part of sodium carboxymethyl cellulose is added and stirred to obtain a modified solution; The silane coupling agent of this embodiment is silane coupling agent KH560; the mass fraction of the sodium dodecyl sulfate solution is 2%.

[0025] The mass fraction of the lanthanum chloride solution of the present embodiment is 2%.

[0026] The preparation method of the ball mill of this embodiment is: S11: irradiating the nano zinc oxide in a proton irradiation box for 1 hour at an irradiation power of 350 W, and obtaining irradiated nano zinc oxide after the irradiation is completed; S12: 1 part of nano-silica sol, 5 parts of sodium lignin sulfonate solution, 3 parts of nano-titanium dioxide and 2 parts of yttrium oxide are stirred to obtain a ball milling solution; S13: The irradiated nano zinc oxide is immersed in a ball milling solution with a volume 3 times the total volume of the irradiated nano zinc oxide, and then ultrasonically treated. After the immersion is completed, a ball milling agent is obtained.

[0027] The mass fraction of the sodium lignin sulfonate solution in this embodiment is 2%.

[0028] The ultrasonic power of the immersion ultrasonic treatment in this embodiment is 450 W, and the ultrasonic treatment is performed for 1 hour.

[0029] The sodium battery negative electrode material is prepared by a method for preparing a sodium battery negative electrode material in this embodiment.

[0030] Example 2. The method for preparing a negative electrode material for a sodium battery of the present embodiment comprises the following steps: Step 1: crush the walnut shell to 10µm and then carbonize it at 1200℃ for 2h to obtain hard carbon particles; Step 2: adding the hard carbon particles into a sufficient amount of the modification liquid and stirring for modification treatment, filtering and drying after the stirring is completed to obtain a modified hard carbon body; Step 3: Mix the modified hard carbon and the ball milling agent in a weight ratio of 5:3 and perform ball milling at a ball milling speed of 1000 r / min for 1 hour. After the ball milling is completed, filter and dry to obtain the sodium battery negative electrode material.

[0031] The stirring speed of the stirring modification treatment in this embodiment is 850 r / min, and the stirring is for 1 hour.

[0032] The preparation method of the modified liquid of this embodiment is: S1: preheat the carbon nanotubes at 75°C for 1 h, then mix and ball-mill 7 parts of the preheated carbon nanotubes, 3 parts of lanthanum chloride solution, and 2 parts of diatomaceous earth at a ball-milling speed of 1500 r / min for 2 h. After the ball-milling is completed, filter and dry; S2: The product of S1 was calcined at 230°C for 1 h, then the temperature was reduced to 65°C at a rate of 3°C / min and kept warm to obtain a modified filler; S3: 7 parts of modified filler and 3 parts of silane coupling agent are added to 8 parts of sodium dodecyl sulfate solution, and then 2 parts of sodium carboxymethyl cellulose are added and stirred to obtain a modified solution; The silane coupling agent in this embodiment is silane coupling agent KH560; the mass fraction of the sodium dodecyl sulfate solution is 5%.

[0033] The mass fraction of the lanthanum chloride solution of the present embodiment is 5%.

[0034] The preparation method of the ball mill of this embodiment is: S11: irradiating the nano zinc oxide in a proton irradiation box for 1 hour at an irradiation power of 350 W, and obtaining irradiated nano zinc oxide after the irradiation is completed; S12: 2 parts of nano-silica sol, 7 parts of sodium lignin sulfonate solution, 5 parts of nano-titanium dioxide and 3 parts of yttrium oxide are stirred to obtain a ball milling solution; S13: The irradiated nano zinc oxide is immersed in a ball milling solution of 5 times the total amount of the irradiated nano zinc oxide, and then ultrasonically treated. After the immersion is completed, a ball milling agent is obtained.

[0035] The mass fraction of the sodium lignin sulfonate solution in this embodiment is 5%.

[0036] The ultrasonic power of the immersion ultrasonic treatment in this embodiment is 500W, and the ultrasonic treatment is performed for 1 hour.

[0037] The sodium battery negative electrode material is prepared by a method for preparing a sodium battery negative electrode material in this embodiment.

[0038] Example 3. The method for preparing a negative electrode material for a sodium battery of the present embodiment comprises the following steps: Step 1: crush the walnut shell to 10µm and then carbonize it at 1200℃ for 2h to obtain hard carbon particles; Step 2: adding the hard carbon particles into a sufficient amount of the modification liquid and stirring for modification treatment, filtering and drying after the stirring is completed to obtain a modified hard carbon body; Step 3: Mix the modified hard carbon and the ball milling agent in a weight ratio of 5:3 and perform ball milling at a ball milling speed of 1000 r / min for 1 hour. After the ball milling is completed, filter and dry to obtain the sodium battery negative electrode material.

[0039] The stirring speed of the stirring modification treatment in this embodiment is 800 r / min, and the stirring is for 1 hour.

[0040] The preparation method of the modified liquid of this embodiment is: S1: preheat the carbon nanotubes at 72°C for 1 h, then mix and ball-mill 5.5 parts of the preheated carbon nanotubes, 2.5 parts of lanthanum chloride solution, and 1.5 parts of diatomaceous earth at a ball-milling speed of 1500 r / min for 2 h. After the ball-milling is completed, filter and dry; S2: The product of S1 was calcined at 225°C for 1 h, then the temperature was reduced to 65°C at a rate of 2°C / min and kept warm to obtain a modified filler; S3: 5.5 parts of modified filler and 2.5 parts of silane coupling agent are added to 6.5 parts of sodium dodecyl sulfate solution, and then 1.5 parts of sodium carboxymethyl cellulose is added and stirred to obtain a modified solution; The silane coupling agent in this embodiment is silane coupling agent KH560; the mass fraction of the sodium dodecyl sulfate solution is 3.5%.

[0041] The mass fraction of the lanthanum chloride solution of the present embodiment is 3.5%.

[0042] The preparation method of the ball mill of this embodiment is: S11: irradiating the nano zinc oxide in a proton irradiation box for 1 hour at an irradiation power of 350 W, and obtaining irradiated nano zinc oxide after the irradiation is completed; S12: 1.5 parts of nano-silica sol, 6 parts of sodium lignin sulfonate solution, 4 parts of nano-titanium dioxide and 2.5 parts of yttrium oxide are stirred to obtain a ball milling solution; S13: The irradiated nano zinc oxide is immersed in a ball milling solution of 4 times the total amount of the irradiated nano zinc oxide, and then ultrasonically treated. After the immersion is completed, a ball mill is obtained.

[0043] The mass fraction of the sodium lignin sulfonate solution in this embodiment is 3.5%.

[0044] The ultrasonic power of the immersion ultrasonic treatment in this embodiment is 475W, and the ultrasonic treatment is performed for 1 hour.

[0045] The sodium battery negative electrode material is prepared by a method for preparing a sodium battery negative electrode material in this embodiment.

[0046] Comparative Example 1. The difference from Example 3 is that no modification liquid treatment was used.

[0047] Comparative Example 2. The difference from Example 3 is that no modified filler is added to the modified liquid.

[0048] Comparative Example 3. The difference from Example 3 is that the modified filler is replaced by carbon nanotubes.

[0049] Comparative Example 4. The difference from Example 3 is that no ball milling agent is used.

[0050] Comparative Example 5. The difference from Example 3 is that no irradiated nano zinc oxide is added to the ball mill.

[0051] Comparative Example 6. The difference from Example 3 is that nano titanium dioxide and yttrium oxide are not added to the ball mill.

[0052] The product performance tests of Examples 1-3 and Comparative Examples 1-6 are as follows:

[0053] It can be seen from Comparative Examples 1-6 and Example 3 that the product of Example 3 has an excellent cycle capacity retention rate, and the product has a significant discharge capacity under high rate conditions; The product was not treated with a modifying liquid and was not treated with a ball mill. The performance of the product showed a significant trend of deterioration. At the same time, no modified filler was added to the modifying liquid, the modified filler was replaced by carbon nanotubes, irradiated nano zinc oxide was not added to the ball mill, and nano titanium dioxide and yttrium oxide were not added to the ball mill. The performance of the product showed a significant trend. The modifying liquid with the modified filler obtained by the specific method of the present invention and the specific ball mill had the most significant product performance effect. Other methods were not as obvious as the effect of the present invention.

[0054] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0055] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a negative electrode material for a sodium battery, characterized in that: The following steps are involved: Step 1: crush the walnut shell to 10µm and then carbonize it at 1200℃ for 2h to obtain hard carbon particles; Step 2: adding the hard carbon particles into a sufficient amount of the modification liquid and stirring for modification treatment, filtering and drying after the stirring is completed to obtain a modified hard carbon body; Step 3: Mix the modified hard carbon and the ball milling agent in a weight ratio of 5:3 and perform ball milling at a ball milling speed of 1000 r / min for 1 hour. After the ball milling is completed, filter and dry to obtain the sodium battery negative electrode material.

2. The method for preparing a negative electrode material for a sodium battery according to claim 1, characterized in that: The stirring speed of the stirring modification treatment is 750-850 r / min, and the stirring is for 1 hour.

3. The method for preparing a negative electrode material for a sodium battery according to claim 2, characterized in that: The preparation method of the modified liquid is: S1: preheating the carbon nanotubes at 70-75°C for 1 hour, then mixing and ball-milling 4-7 parts of the preheated carbon nanotubes, 2-3 parts of lanthanum chloride solution, and 1-2 parts of diatomaceous earth at a ball-milling speed of 1500 r / min for 2 hours, filtering and drying after the ball-milling is completed; S2: The S1 product is calcined at 220-230°C for 1 hour, then cooled to 65°C at a rate of 1-3°C / min and kept warm to obtain a modified filler; S3: 4-7 parts of modified filler and 2-3 parts of silane coupling agent are added to 5-8 parts of sodium dodecyl sulfate solution, and then 1-2 parts of sodium carboxymethyl cellulose are added and stirred thoroughly to obtain a modified solution.

4. The method for preparing a negative electrode material for a sodium battery according to claim 3, characterized in that: The silane coupling agent is silane coupling agent KH560; the mass fraction of the sodium dodecyl sulfate solution is 2-5%.

5. The method for preparing a negative electrode material for a sodium battery according to claim 3, characterized in that: The mass fraction of the lanthanum chloride solution is 2-5%.

6. The method for preparing a negative electrode material for a sodium battery according to claim 3, characterized in that: The preparation method of the ball mill is: S11: irradiating the nano zinc oxide in a proton irradiation box for 1 hour at an irradiation power of 350 W, and obtaining irradiated nano zinc oxide after the irradiation is completed; S12: 1-2 parts of nano-silica sol, 5-7 parts of sodium lignin sulfonate solution, 3-5 parts of nano-titanium dioxide and 2-3 parts of yttrium oxide are stirred to obtain a ball milling solution; S13: The irradiated nano zinc oxide is immersed in a ball milling solution of 3-5 times the total amount of the irradiated nano zinc oxide, and then ultrasonically treated. After the immersion is completed, a ball mill is obtained.

7. The method for preparing a negative electrode material for a sodium battery according to claim 6, characterized in that: The mass fraction of the sodium lignin sulfonate solution is 2-5%.

8. The method for preparing a negative electrode material for a sodium battery according to claim 6, characterized in that: The ultrasonic power of the immersion ultrasonic treatment is 450-500W, and the ultrasonic treatment is performed for 1 hour.

9. A sodium battery negative electrode material prepared by the method for preparing a sodium battery negative electrode material according to any one of claims 1 to 8.

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