Modified lignocellulose separator for lithium ion battery and its preparation method and application

Abstract

The invention relates to a modified lignocellulose diaphragm for lithium ion batteries and its preparation method and application. The lignocellulose diaphragm is made of a natural wood film with a thickness of 30-300 μm, which is treated with a mixed lye and placed in a vacuum environment It is obtained by mixing lye and fully immersing the interior of the wood film and treating it at high temperature. Compared with the prior art, the lithium-ion battery separator based on natural lignocellulose prepared by the present invention not only has high ion conductivity, thermal stability, and excellent mechanical strength, but also has the advantages of low cost and abundant raw materials. The preparation method of the diaphragm is very simple, and the cut micron-level natural wood film can be obtained by one-step modification in a mixed solution of potassium hydroxide and sodium sulfite. This method greatly simplifies the preparation process, effectively reduces the cost, and is expected to realize green, low-cost, and large-scale application.

Description

technical field

[0001] The invention relates to the technical field of energy storage devices, in particular to a modified lignocellulose separator for a lithium ion battery and a preparation method and application thereof. Background technique

[0002] Lithium-ion batteries mainly include positive and negative electrode materials, separators, electrolytes, etc. The main function of the separator is to avoid direct contact between the positive and negative electrodes and cause a short circuit, or even a battery explosion accident, which is an important part of the battery. To a certain extent, the quality of the separator determines the energy storage efficiency, thermal stability and safety of the battery. At present, the research on positive electrode materials and negative electrode materials is flourishing, but the separator, as a key component of the battery, has been studied relatively little. The development of new high-performance separators is the focus of comprehen...

Examples

Embodiment 1

[0041] A lithium ion battery with a modified natural lignocellulose diaphragm, the specific preparation method is as follows:

[0042] (1) Thinning the pre-selected poplar wood to a film with a thickness of 50 μm, the schematic diagram of the preparation process is as follows figure 1 shown;

[0043] (2) The natural wood film obtained above is pretreated in an alkaline solution, and the specific process is as follows: 3 g of potassium hydroxide is dissolved in 60 mL of deionized water, stirred for 10 min to obtain a uniform solution; then 2 g of sodium sulfite is weighed and added to the above solution , after stirring for 10 min, a homogeneous solution was obtained. Then immerse the natural wood film in the above solution, place it in a vacuum oven, and under negative pressure, make the mixed alkali solution fully soak the wood film, take it out after half an hour, transfer it to the reaction kettle, and take it out after reacting at 100°C for 5 hours. Wash with deionized w...

Embodiment 2

[0056] A lithium ion battery with a modified natural lignocellulose diaphragm, the specific preparation method is as follows:

[0057] (1) Thin the pre-selected basswood to about 150μm.

[0058] (2) The basswood film obtained above is pretreated in alkaline solution, and the specific process is as follows: in 90ml deionized water, add 6g potassium hydroxide and dissolve in 90mL deionized water, stir for 30min to obtain a uniform solution; then weigh Add 4.5 g of sodium sulfite to the above solution, and stir for 30 minutes to obtain a homogeneous solution. Then submerge the natural wood film in the above solution, place it in a vacuum oven, and under negative pressure, make the mixed alkali solution fully soak the wood diaphragm, take it out after half an hour, transfer it to the reaction kettle, and take it out after reacting at 120°C for 12 hours , repeatedly washed with deionized water until neutral. Clamp it with a glass sheet at room temperature, and gradually dry it sl...

Embodiment 3

[0063] A lithium ion battery with a modified natural lignocellulose diaphragm, the specific preparation method is as follows:

[0064] (1) Thinning the pre-selected natural pine wood to about 300μm.

[0065] (2) The above-mentioned natural wood film is pretreated in an alkaline solution, and the specific process is as follows: 8g of potassium hydroxide is dissolved in 120mL of deionized water, stirred for 60min to obtain a uniform solution; then 8g of sodium sulfite is weighed and added to the above solution, stirred After 60 min, a homogeneous solution was obtained. Then submerge the natural wood film in the above solution, place it in a vacuum oven, and under negative pressure, make the mixed alkali solution fully soak the wood diaphragm, take it out after half an hour, transfer it to the reaction kettle, and take it out after reacting at 140°C for 24 hours , repeatedly washed with deionized water until neutral. Clamp it with a glass sheet at room temperature, and graduall...

technical field

[0001] The invention relates to the technical field of energy storage devices, in particular to a modified lignocellulose separator for a lithium ion battery and a preparation method and application thereof. Background technique

[0002] Lithium-ion batteries mainly include positive and negative electrode materials, separators, electrolytes, etc. The main function of the separator is to avoid direct contact between the positive and negative electrodes and cause a short circuit, or even a battery explosion accident, which is an important part of the battery. To a certain extent, the quality of the separator determines the energy storage efficiency, thermal stability and safety of the battery. At present, the research on positive electrode materials and negative electrode materials is flourishing, but the separator, as a key component of the battery, has been studied relatively little. The development of new high-performance separators is the focus of comprehen...

Examples

Embodiment 1

[0041] A lithium ion battery with a modified natural lignocellulose diaphragm, the specific preparation method is as follows:

[0042] (1) Thinning the pre-selected poplar wood to a film with a thickness of 50 μm, the schematic diagram of the preparation process is as follows figure 1 shown;

[0043] (2) The natural wood film obtained above is pretreated in an alkaline solution, and the specific process is as follows: 3 g of potassium hydroxide is dissolved in 60 mL of deionized water, stirred for 10 min to obtain a uniform solution; then 2 g of sodium sulfite is weighed and added to the above solution , after stirring for 10 min, a homogeneous solution was obtained. Then immerse the natural wood film in the above solution, place it in a vacuum oven, and under negative pressure, make the mixed alkali solution fully soak the wood film, take it out after half an hour, transfer it to the reaction kettle, and take it out after reacting at 100°C for 5 hours. Wash with deionized w...

Embodiment 2

[0056] A lithium ion battery with a modified natural lignocellulose diaphragm, the specific preparation method is as follows:

[0057] (1) Thin the pre-selected basswood to about 150μm.

[0058] (2) The basswood film obtained above is pretreated in alkaline solution, and the specific process is as follows: in 90ml deionized water, add 6g potassium hydroxide and dissolve in 90mL deionized water, stir for 30min to obtain a uniform solution; then weigh Add 4.5 g of sodium sulfite to the above solution, and stir for 30 minutes to obtain a homogeneous solution. Then submerge the natural wood film in the above solution, place it in a vacuum oven, and under negative pressure, make the mixed alkali solution fully soak the wood diaphragm, take it out after half an hour, transfer it to the reaction kettle, and take it out after reacting at 120°C for 12 hours , repeatedly washed with deionized water until neutral. Clamp it with a glass sheet at room temperature, and gradually dry it sl...

Embodiment 3

[0063] A lithium ion battery with a modified natural lignocellulose diaphragm, the specific preparation method is as follows:

[0064] (1) Thinning the pre-selected natural pine wood to about 300μm.

[0065] (2) The above-mentioned natural wood film is pretreated in an alkaline solution, and the specific process is as follows: 8g of potassium hydroxide is dissolved in 120mL of deionized water, stirred for 60min to obtain a uniform solution; then 8g of sodium sulfite is weighed and added to the above solution, stirred After 60 min, a homogeneous solution was obtained. Then submerge the natural wood film in the above solution, place it in a vacuum oven, and under negative pressure, make the mixed alkali solution fully soak the wood diaphragm, take it out after half an hour, transfer it to the reaction kettle, and take it out after reacting at 140°C for 24 hours , repeatedly washed with deionized water until neutral. Clamp it with a glass sheet at room temperature, and graduall...

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