阅读说明：本技术 一种锂离子交换法改性黑云母制备负极材料的方法 (Method for preparing negative electrode material by modifying biotite through lithium ion exchange method ) 是由 黄志良 程怡林 姚东辉 吴昌胜 陈松 于 2019-10-30 设计创作，主要内容包括：本发明涉及一种锂离子交换法改性黑云母制备负极材料的方法,该负极材料为水合锂云母,通过锂离子置换黑云母中钾离子制备得到。本发明利用锂离子交换法提取钾离子,提取成本较低,速度快,环境友好,保留了黑云母典型的层状结构,制备得到的负极材料比电容有明显提升,且黑云母价格低廉,降低了电极材料的制备成本,为电极材料的发展提供多一种选择,具有广阔的应用前景。(The invention relates to a method for preparing a negative electrode material by modifying biotite through a lithium ion exchange method, wherein the negative electrode material is hydrated lepidolite and is prepared by replacing potassium ions in the biotite with lithium ions. The method for extracting the potassium ions by using the lithium ion exchange method has the advantages of low extraction cost, high speed and environmental friendliness, retains the typical layered structure of the biotite, obviously improves the specific capacitance of the prepared cathode material, has low price of the biotite, reduces the preparation cost of the electrode material, provides a plurality of choices for the development of the electrode material, and has wide application prospect.)

1. The method for preparing the negative electrode material by modifying the biotite through the lithium ion exchange method is characterized in that the negative electrode material is hydrated lepidolite and is prepared by replacing potassium ions in the biotite with lithium ions.

2. The method according to claim 1, characterized in that it comprises in particular the steps of:

1) pulverizing biotite ore and sieving;

2) mixing the biotite obtained in the step 1) with an aqueous solution of a soluble lithium salt, adding an acid solution to adjust the mixed solution to be acidic, heating for reaction, filtering and drying to obtain the hydrated lepidolite negative electrode material.

3. The method as claimed in claim 2, wherein the biotite ore is crushed in step 1) and then passed through a 200-mesh screen.

4. The method as claimed in claim 2, wherein the pH of the mixed solution is adjusted to 1.3-1.5 by adding an acid solution before the reaction in step 2).

5. The method of claim 2, wherein in the step 2), the concentration of the soluble lithium salt aqueous solution is 0.77-0.80 mol/L; the mass volume ratio of the biotite to the soluble lithium salt aqueous solution is 1 g: 245-250 ml.

6. The method of claim 2, wherein in step 2), the soluble lithium salt is lithium nitrate.

7. The method as claimed in claim 2, wherein in the step 2), the acid solution is diluted hydrochloric acid with a concentration of 0.4-0.6 mol/L.

8. The method as claimed in claim 2, wherein the heating reaction conditions in step 2) are as follows: the temperature is 70-80 ℃, and the reaction time is 5-10 h.

9. The method of claim 8, wherein the heating reaction conditions are: the reaction temperature is 80 ℃, and the reaction time is 8-10 h.

Technical Field

The invention relates to the technical fields of chemistry, new energy development and the like, in particular to a method for preparing a negative electrode material by modifying biotite through a lithium ion exchange method.

Technical Field

Biotite as a mineral of the mica group having a typical layered silicate structure, in the crystal structure of the mica group, [ SiO ]₄]Tetrahedral layer and [ AlO ]₆]The ratio of the octahedral layer is 1: 2, SiO in mica structural unit layer₄]The obvious Al-Si substitution phenomenon exists in the tetrahedral sheet layer, which becomes 'isomorphism substitution' in the mineralogy, which causes that the structural unit layer has a large amount of negative charges, and the layers need to absorb the same amount of positive charges and cations, thereby realizing that the mica is integrally electrifiedAnd (4) the product is neutral. The biotite ore has abundant reserves, low price, excellent physical and chemical properties and wide application and research, and is mainly applied to the building material industry, the fire-fighting industry, the fire extinguishing agent, the plastic, the papermaking and other chemical industries. In the field of plastics industry, biotite is mainly used as a filler, which can increase strength and improve a series of properties of plastic products, including heat resistance and dimensional stability. The biotite has a typical layered structure, is very similar to the layered structure of a graphene negative electrode material, and has the potential of being used as an electrode material, but the biotite has poor electrical properties and cannot be directly used as the electrode material, so that a simple and effective method for modifying the biotite is required to be found, and the biotite is used in a battery electrode.

Disclosure of Invention

The invention mainly aims to provide a method for preparing a negative electrode material by modifying biotite through a lithium ion exchange method. The cathode material obtained by the method has good electrochemical performance, low cost and environmental friendliness, and has wide application prospects in the fields of novel solid batteries, chemical sensors, electrode materials and the like.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

the method for preparing the negative electrode material by modifying the biotite through the lithium ion exchange method is provided, the negative electrode material is hydrated lepidolite, and the negative electrode material is prepared by replacing potassium ions in the biotite with lithium ions.

According to the scheme, the method specifically comprises the following steps:

1) pulverizing biotite ore and sieving;

2) mixing the biotite obtained in the step 1) with an aqueous solution of a soluble lithium salt, adding an acid solution to adjust the mixed solution to be acidic, heating for reaction, filtering and drying to obtain the hydrated lepidolite negative electrode material.

According to the scheme, the biotite ore in the step 1) is crushed and then passes through a 200-mesh screen.

According to the scheme, the acid solution is added before the reaction in the step 2) to adjust the pH value of the mixed solution to 1.3-1.5.

According to the scheme, the concentration of the soluble lithium salt aqueous solution in the step 2) is 0.77-0.80mol/L, and the mass-volume ratio of the biotite to the soluble lithium salt aqueous solution is 1 g: 245-250 ml.

According to the scheme, the soluble lithium salt in the step 2) is lithium nitrate.

According to the scheme, the acid solution in the step 2) is dilute hydrochloric acid, and the concentration is 0.4-0.6 mol/L.

According to the scheme, the heating reaction conditions in the step 2) are as follows: the temperature is 70-80 ℃, and the reaction time is 5-10 h; preferably, the reaction temperature is 80 ℃ and the reaction time is 8-10 h.

According to the invention, the negative electrode material is prepared by modifying the biotite through a lithium ion exchange method, and the biotite is modified through the lithium ion exchange method, on one hand, potassium ions and lithium ions are located in the same main group of the periodic table of elements, the structure and the property of the biotite are similar, the radius ratio of the lithium ions is smaller, the biotite can enter into the layers of the biotite more easily to hydrolyze and exchange with the potassium ions, the biotite becomes hydrated lithium ions after hydrolysis, the ion radius is larger, the constraint of the layers on the potassium ions is smaller, and the potassium ions can be replaced more easily; the lithium ions are monovalent ions, one lithium ion can replace one potassium ion, and for the divalent ions, one divalent ion can replace two potassium ions, compared with the divalent ions, the number of hydrated lithium ions entering the interlayer is more, more storage sites can be provided for electrons, the storage and release of the electrons are facilitated, and the energy density of the cathode material is improved.

The invention has the beneficial effects that:

1. the hydrated lepidolite negative electrode material is prepared by extracting potassium ions by using a lithium ion exchange method, has low extraction cost, high speed and environmental friendliness, retains the typical layered structure of the biotite, obviously improves the obtained negative electrode material compared with the capacitance, and has wide application prospect in the fields of novel solid batteries, chemical sensors, electrode materials and the like.

2. According to the invention, lithium ions are used for exchanging potassium ions in the biotite, the lithium ions are monovalent, and compared with divalent ions, more hydrated lithium ions are used for carrying out interlamination of the biotite, so that more storage sites are provided for electrons, the storage and release of the electrons are facilitated, and the specific capacitance of the cathode material is improved.

3. The biotite ore has abundant reserves and low price, and the modified biotite is used in the electrode material, so that the preparation cost of the electrode material is reduced, and the electrode material has wide application prospects.

4. The biotite has a typical layered structure similar to graphene and has the potential of being used as an electrode material, and the invention provides a plurality of options for the development of the electrode material by modifying the biotite to be used in the electrode material.

Drawings

Fig. 1 is an XRD pattern of biotite raw ore.

FIG. 2 is a cyclic charge and discharge curve of raw biotite at a current density of 0.2A/g.

Fig. 3 is an XRD pattern of the hydrous lepidolite anode material prepared in example 1.

FIG. 4 is a cyclic charge and discharge curve of the hydrated lepidolite negative electrode material prepared in example 1 at a current density of 0.2A/g.

Fig. 5 is an XRD pattern of the hydrous lepidolite negative electrode material prepared in example 2.

FIG. 6 is a cyclic charge and discharge curve of the hydrated lepidolite negative electrode material prepared in example 2 at a current density of 0.2A/g.

Detailed Description

In order to make those skilled in the art fully understand the technical solutions and advantages of the present invention, the following description is further provided with reference to the specific embodiments and the accompanying drawings.

The potassium extraction rate is as follows: the lithium ion exchange rate refers to the exchange ratio of lithium ions to potassium ions in the reaction process, and the larger the exchange ratio of lithium ions to potassium ions is, the higher the potassium extraction rate is.

XRD pattern d₍₀₀₁₎The change of the potassium extraction rate can reflect whether the lithium ions are replaced between the biotite layers, and the potassium extraction rate I can quantitatively calculate the exchange degree of the lithium ions and the potassium ions, and the formula is as follows:

wherein, I_(001)*Is newly generated d in XRD pattern_(001)*Intensity of diffraction Peak, I₍₀₀₁₎Is original position d (in XRD pattern)₀₀₁) Intensity of diffraction peak.