Thermal treatment preparation method of silicon negative electrode plate

Abstract

The invention relates to the technical field of preparation of a silicon negative electrode plate, and specifically provides a thermal treatment preparation method of the silicon negative electrode plate. The thermal treatment preparation method comprises the following steps: S1, coating a coated big silicon negative electrode roll or a formed small silicon negative electrode plate by adopting a copper foil or an aluminum foil; S2, putting the coated plate in a high-temperature baking oven, and carrying out thermal treatment under a vacuum or inert gas protection condition; S3, taking out theplate after thermal treatment, cooling to room temperature, and annealing under a vacuum condition. According to the thermal treatment preparation method provided by the invention, a negative electrode after the thermal treatment requires not to be cooled in the high-temperature baking oven, and can be directly taken out and transferred to a normal temperature baking oven for cooling; the purposeof thermal polymerization of a polymer adhesive can be achieved, oxidation of the silicon negative electrode cannot be caused; the thermal treatment preparation method provided by the invention is simple in operation and short in time, and is beneficial for industrial production.

Description

technical field [0001] The invention relates to the technical field of preparation of silicon negative pole pieces, in particular to a heat treatment preparation method of silicon negative pole pieces. Background technique [0002] Due to the advantages of high working voltage and high energy density, lithium-ion batteries are widely used in digital products, power tools, and drones. However, due to material limitations, the development of lithium-ion batteries has entered a bottleneck period, and the energy density cannot be achieved. Further improvement has been achieved. The theoretical specific capacity of silicon is as high as 4200mAh / g, and its reserves are abundant, making it an ideal negative electrode material. However, during the charging and discharging process of silicon negative electrodes, the lithium intercalation and desorption of silicon is accompanied by huge volume expansion, which causes the pulverization of the material. , The electrode material peels of...

AI Technical Summary

Problems solved by technology

[0002] Due to the advantages of high working voltage and high energy density, lithium-ion batteries are widely used in digital products, power tools, and drones. However, due to material limitations, the development of lithium-ion batteries has entered a bottleneck period, and the energy density cannot be achieved. Further improvement has been achieved. The theoretical specific capacity of silicon is as high as 4200mAh / g, and its reserves are abundant, making it an ideal negative electrode material. However, during the charging and discharging process of silicon negative electrodes, the lithium intercalation and desorption of silicon is accompanied by huge volume expansion, which causes the pulverization of the material. , the electrode material peels off, the resistance increases significantly, and the cycle performance of the battery drops sharply

In order to solve the expansion problem of the silicon negative electrode, polymer binders can be used instead of traditional binders such as PVDF and styrene-butadiene rubber. shape structure, which can improve its bonding performance, but the traditional heat treatment process is cumbersome and can only be carried out in a tube furnace or other furnace body with protective gas, and only a very small amount of pole pieces can be processed each time, the entire heating and cooling process The time required is too long. The long-term heating and cooling process will not only easily lead to the failure of the binder and poor bonding performance, but also easily oxidize the foil material and deteriorate the silicon negative electrode material.

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