阅读说明：本技术 一种掺磷多孔碳包覆氧化亚硅材料的制备方法及其产品 (Preparation method of phosphorus-doped porous carbon-coated silica material and product thereof ) 是由 崔大祥 王亚坤 张芳 颜雪冬 葛美英 卢玉英 王金 张放为 焦靖华 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种磷掺杂多孔碳包覆氧化亚硅材料的制备方法及其产品,以植酸为碳源和磷源,对氧化亚硅进行包覆改性,最终得到一种以掺磷多孔碳为包覆层的核壳结构的复合材料。其中氧化亚硅的质量比为90%～97%,植酸的质量比为3%～10%。本发明公开的复合材料,不仅提高了氧化亚硅的导电性,还有效缓冲了氧化亚硅在充放电过程中的体积膨胀,改善了材料的稳定性和容量。(The invention discloses a preparation method of a phosphorus-doped porous carbon-coated silicon monoxide material and a product thereof. Wherein the mass ratio of the silicon monoxide is 90-97%, and the mass ratio of the phytic acid is 3-10%. The composite material disclosed by the invention not only improves the conductivity of the silicon oxide, but also effectively buffers the volume expansion of the silicon oxide in the charging and discharging processes, and improves the stability and capacity of the material.)

1. A preparation method of a phosphorus-doped porous carbon-coated silica material is characterized in that phytic acid is used as a carbon source and a phosphorus source to carry out coating modification on the silica to obtain a composite material with a core-shell structure and a phosphorus-doped porous carbon as a coating layer, and comprises the following steps:

s1: dissolving a certain mass part of phytic acid in deionized water, continuously stirring on a heatable magnetic stirrer, adding a corresponding mass part of silicon monoxide, starting heating, continuously stirring until the solution becomes viscous, transferring the solution into an oven, and continuously drying, wherein the mass part of the phytic acid is 3-10%, and the mass part of the silicon monoxide is 90-97%;

s2: and transferring the dried material into a tubular furnace, heating to the first-stage temperature of 600-800 ℃ in an inert atmosphere, preserving heat for 2-5 h, continuously heating to the second-stage temperature of 850-1000 ℃, preserving heat for 1-2 h, and naturally cooling to room temperature to obtain the phosphorus-doped porous carbon coated silica material.

2. The method of preparing a phosphorus-doped porous carbon-coated silica material of claim 1, wherein: the particle size D50 of the silica in S1 is 3-7 μm.

3. The method of preparing a phosphorus-doped porous carbon-coated silica material of claim 1, wherein: in S1, the heating and stirring temperature is 70-90 ℃, and the drying temperature is 80-90 ℃.

4. The method of preparing a phosphorus-doped porous carbon-coated silica material of claim 1, wherein: in S2, the temperature rise rate is 1-5 ℃/min.

5. The method of preparing a phosphorus-doped porous carbon-coated silica material according to any one of claims 1 to 4, comprising the steps of:

s1: dissolving 0.5g of phytic acid in deionized water, adding 9.5g of silica while continuously stirring on a heatable magnetic stirrer, starting to heat to 70 ℃, continuously stirring until the solution becomes viscous, and transferring the solution into an oven at 80 ℃ for continuous drying;

s2: and transferring the dried material into a tubular furnace, heating to 600 ℃ at a heating rate of 3 ℃/min in an inert atmosphere, keeping the temperature for 4h, continuously heating to 900 ℃ in a second stage, keeping the temperature for 2h, and naturally cooling to room temperature to obtain the phosphorus-doped porous carbon coated silica material.

6. The method of preparing a phosphorus-doped porous carbon-coated silica material according to any one of claims 1 to 4, comprising the steps of:

s1: dissolving 1g of phytic acid in deionized water, continuously stirring and adding 9g of silicon monoxide on a heatable magnetic stirrer, starting to heat to 70 ℃, continuously stirring until the solution becomes viscous, and transferring the solution into an oven to be dried continuously at 80 ℃;

s2: and transferring the dried material into a tubular furnace, heating to 700 ℃ at a heating rate of 5 ℃/min in an inert atmosphere, keeping the temperature for 3h, continuously heating to 950 ℃ and keeping the temperature for 1h, and naturally cooling to room temperature to obtain the phosphorus-doped porous carbon-coated cuprous oxide material.

7. The method of preparing a phosphorus-doped porous carbon-coated silica material according to any one of claims 1 to 4, comprising the steps of:

s1: dissolving 0.6g of phytic acid in deionized water, adding 9.4g of silica while continuously stirring on a heatable magnetic stirrer, starting to heat to 90 ℃, continuously stirring until the solution becomes viscous, and transferring into an oven for continuous drying at 80 ℃;

s2: and transferring the dried material into a tubular furnace, heating to 700 ℃ at a heating rate of 5 ℃/min in an inert atmosphere, keeping the temperature for 4h, continuously heating to 1000 ℃ and keeping the temperature for 1h, and naturally cooling to room temperature to obtain the phosphorus-doped porous carbon-coated cuprous oxide material.

8. A phosphorus-doped porous carbon-coated silica material characterized by being prepared according to the method of any one of claims 1 to 7.

Technical Field

The invention relates to a preparation method of a phosphorus-doped porous carbon-coated silicon protoxide material and a product thereof.

Background

Portable electronic devices, electric vehicles, and energy storage systems have increasingly stringent requirements for high specific energy, high specific power, long life, and low cost secondary batteries. Lithium ion batteries have become a major concern in the field of secondary energy due to their numerous advantages.

The performance of the battery depends mainly on the electrode material. Si-based material as negative electrode material of lithium ion battery, and Li can be formed by Si-based material and lithium₂₂ Si ₅ The alloy has high specific capacity (up to 4200 mAhg) ^-1) Is graphite (372 mAhg) which is commonly used at present ^-1) As much as ten times as much material. And which has a low potential for lithium deintercalation (about 0.1-0.3V vs Li/Li)⁺) The reaction activity with the electrolyte is low, the cost is low, and a long discharge platform can be provided. However, since the Si material undergoes a large volume expansion (about 400%) during charging, it causes separation between electrode materials and between the electrode material and a current collector, and electrical contact is lost, thereby causing rapid capacity fade and rapid cycle performance deterioration. Due to their high specific capacity and good cycling performance, silicon-based sub-oxides have recently received extensive attention and research. But oxygenThe conductivity of the silicon carbide is much lower than that of graphite, so that severe polarization occurs when a large current is discharged.

Disclosure of Invention

The invention aims to provide a preparation method of a phosphorus-doped porous carbon-coated silicon protoxide material.

Yet another object of the present invention is to: provides a phosphorus-doped porous carbon-coated silicon protoxide material product prepared by the method.

The invention aims to provide the following scheme for realizing: a preparation method of a phosphorus-doped porous carbon-coated silica material is characterized in that phytic acid is used as a carbon source and a phosphorus source to coat and modify the silica, and finally a composite material with a core-shell structure and a phosphorus-doped porous carbon as a coating layer is obtained, wherein the method comprises the following steps:

s1: dissolving phytic acid with a certain mass fraction in deionized water, continuously stirring on a heatable magnetic stirrer, adding the corresponding mass fraction of silicon monoxide, starting heating, continuously stirring until the solution becomes viscous, and transferring the solution into an oven for continuous drying;

s2: and transferring the dried material into a tubular furnace, heating to the first section temperature in an inert atmosphere, keeping the temperature for a certain time, continuously heating to the second section temperature, keeping the temperature for a certain time, and naturally cooling to room temperature to obtain the phosphorus-doped porous carbon-coated silica material.

The particle size D50 of the silica in S1 is about 3-7 μm.

In the S1, the phytic acid accounts for 3-10% by mass, and the silicon monoxide accounts for 90-97% by mass.

In S1, the heating and stirring temperature is 70-90 ℃, and the drying temperature is 80-90 ℃.

In S2, the heating rate is 1-5 ℃/min.

In S2, the temperature of the first section is 600-800 ℃, and the heat preservation time is 2-5 h.

And in the S2, the temperature of the second section is 850-1000 ℃, and the heat preservation time is 1-2 h.

The invention provides a phosphorus-doped porous carbon-coated silica material prepared by any one of the methods.

The composite material with the core-shell structure and the phosphorus-doped porous carbon as the coating layer is finally obtained by coating and modifying the silicon oxide by taking phytic acid as a carbon source and a phosphorus source, so that the conductivity of the silicon oxide is improved, the volume expansion of the silicon oxide in the charging and discharging processes is effectively buffered, and the stability and the capacity of the material are improved.

Drawings

FIG. 1 is a graph of the first effect performance of the phosphorus-doped porous carbon-coated silica material obtained in example 1;

FIG. 2 is an SEM photograph of the phosphorus-doped porous carbon-coated silica material obtained in example 1.

Detailed Description

The invention will be further elucidated by means of specific embodiments, without being limited thereto, in conjunction with the accompanying drawings.

Example 1

A phosphorus-doped porous carbon-coated silicon monoxide material is prepared by taking phytic acid as a carbon source and a phosphorus source, coating and modifying the silicon monoxide to obtain a composite material with a core-shell structure and taking the phosphorus-doped porous carbon as a coating layer, and the preparation method comprises the following steps:

s1: dissolving 0.5g of phytic acid in deionized water, adding 9.5g of silica while continuously stirring on a heatable magnetic stirrer, starting to heat to 70 ℃, continuously stirring until the solution becomes viscous, and transferring the solution into an oven at 80 ℃ for continuous drying;

s2: and transferring the dried material into a tubular furnace, heating to 600 ℃ at a heating rate of 3 ℃/min in an inert atmosphere, keeping the temperature for 4h, continuously heating to 900 ℃ in a second stage, keeping the temperature for 2h, and naturally cooling to room temperature to obtain the phosphorus-doped porous carbon coated silica material.

The first effect performance diagram of the obtained phosphorus-doped porous carbon-coated silica material is shown in figure 1, the first effect of the prepared composite material is about 81%, and the capacity of the composite material exceeds 1300 mAh/g.

The SEM image of the obtained phosphorus-doped porous carbon-coated silica material is shown in figure 2, and the SEM image shows that the prepared composite material is uniform in particle size, namely uniform in coating.

Example 2

A phosphorus-doped porous carbon-coated silica material, similar to example 1, prepared by the following steps:

s1: dissolving 1g of phytic acid in deionized water, continuously stirring and adding 9g of silicon monoxide on a heatable magnetic stirrer, starting to heat to 70 ℃, continuously stirring until the solution becomes viscous, and transferring the solution into an oven to be dried continuously at 80 ℃;

s2: and transferring the dried material into a tubular furnace, heating to 700 ℃ at a heating rate of 5 ℃/min in an inert atmosphere, keeping the temperature for 3h, continuously heating to 950 ℃ and keeping the temperature for 1h, and naturally cooling to room temperature to obtain the phosphorus-doped porous carbon-coated cuprous oxide material.

Example 3

A phosphorus-doped porous carbon-coated silica material, similar to example 1, prepared by the following steps:

s1: dissolving 0.6g of phytic acid in deionized water, adding 9.4g of silica while continuously stirring on a heatable magnetic stirrer, starting to heat to 90 ℃, continuously stirring until the solution becomes viscous, and transferring into an oven for continuous drying at 80 ℃;

s2: and transferring the dried material into a tubular furnace, heating to 700 ℃ at a heating rate of 5 ℃/min in an inert atmosphere, keeping the temperature for 4h, continuously heating to 1000 ℃ and keeping the temperature for 1h, and naturally cooling to room temperature to obtain the phosphorus-doped porous carbon-coated cuprous oxide material.