Preparation method of porous sheet-shaped sodium ion battery negative electrode material

Abstract

According to the preparation method, graphene oxide is taken as a template, organic or inorganic titanium is taken as a titanium source, under the action of an alkali catalyst, the titanium source and functional groups on the surface of the graphene oxide form chemical bonds, and the chemical bonds are deposited on the surface of the graphene oxide; the titanium dioxide / graphene oxide / titanium dioxide sandwich framework is obtained. After filtering, drying and calcining, the template is completely removed, and the amorphous titanium dioxide is converted into the mesoporous anatase-phase porous titanium dioxide nanosheet. The particle calcining device can effectively prevent the pore structure from being blocked due to insufficient gasification of the graphene oxide template in the calcining process, so that the prepared mesoporous material has relatively large pore volume and pore diameter, and the porous structure can improve the liquid retention capacity, is beneficial to intercalation and deintercalation of sodium ions, reduces the internal stress of the material, avoids de-molding and sodium separation of a pole piece, and improves the production efficiency. The material is suitable for high-voltage density design and high-rate charge and discharge, and can improve the energy density and rate capability of the battery cell.

Description

technical field [0001] The invention belongs to the technical field of sodium ion batteries, and in particular relates to a method for preparing a negative electrode material of a porous sheet-shaped sodium ion battery. Background technique [0002] The rapid development of lithium-ion battery energy storage technology has expanded the application scope of lithium-ion batteries, and the market share has grown steadily. However, the limited reserves of lithium resources on the earth and the immature battery recycling technology have caused the cost of lithium-ion batteries to increase year by year. The reserves of sodium resources are abundant and widely distributed, and the principle of sodium ion energy storage is similar to that of lithium ion batteries, which has higher safety. With the gradual development of high-performance sodium-ion electrode materials, sodium-ion batteries are expected to replace lithium-ion batteries in the low-end market. [0003] The ionic radiu...

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Problems solved by technology

It can be seen that whether the calcination process can fully remove the graphene or graphene oxide template is crucial to the formation of the mesoporous structure. If there is too much template remaining or insufficient reaction with oxygen, the mesoporous structure will be occupied or blocked by carbon. The pore volume and pore diameter are greatly reduced, which seriously affects the performance of mesoporous materials

[0007] The existing calcination process is carried out in the air using a common calcination furnace. In order to keep warm, the calcination chamber of the common calcination furnace is relatively airtight, and the air circulation is poor. Even if fresh air is continuously introduced, the fresh air will react with the calcination chamber. The mixing of carbon dioxide reduces the oxygen concentration in the fresh air and affects the full oxidation of graphene

In addition, it is difficult for fresh air to enter the interior of the calcined material, especially when the thickness of the material is large, the speed of gas diffusion into the interior of the calcined material is extremely slow, which will cause the graphene template of the surface material to be fully oxidized, and the template The removal degree is higher, the pore structure is formed better, and the internal material is exposed to less oxygen, the oxidation is insufficient, a large amount of carbon residue appears, the template is not fully removed, and the pore structure is poorly formed

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