A kind of lithium ion battery silicon carbon negative electrode material and preparation method

Abstract

The invention relates to the technical field of lithium-ion battery negative electrode materials, in particular to a lithium-ion battery silicon-carbon negative electrode material and a preparation method, which is characterized in that it comprises the following steps: activated carbon material pulverization pretreatment; preparation of nano-silicon slurry; Activated carbon powder is mixed with nano-silicon slurry and coal tar soft pitch; coking treatment; low-temperature carbonization treatment; the product after low-temperature carbonization treatment is crushed and classified, and the product of 5-30 μm is taken as a silicon-carbon negative electrode material. Compared with the prior art, the negative electrode material of the lithium ion battery prepared by the present invention is a silicon-carbon composite material, and nano-silicon and / or silicon oxide are introduced into the activated carbon material, which improves the gram capacity of the negative electrode material of the lithium ion secondary battery. The capacity has exceeded the theoretical capacity of graphite materials, thereby increasing the charge and discharge gram capacity of the battery, and at the same time solving the expansion problem of simply using silicon and silicon oxide as negative electrodes; better solving the volume expansion problem, thus improving the cycle performance.

Description

technical field [0001] The invention relates to the technical field of negative electrode materials for lithium ion batteries, in particular to a silicon carbon negative electrode material for lithium ion batteries and a preparation method thereof. Background technique [0002] Lithium-ion batteries are attractive for their excellent performance in terms of high energy density, high working voltage, small size, light weight, no pollution, fast charging and discharging, and long cycle life. At present, commercially applied anode materials include artificial graphite, natural graphite, and mesophase carbon microspheres, which are essentially graphite-based anode materials, characterized by a good layered structure, suitable for intercalation and extraction of lithium ions, theoretically The reversible lithium storage capacity of graphite can reach 372mAh / g. At present, the actual delithiation capacity of graphite-based anode materials in half-cells has reached 365mAh / g, which ...

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Problems solved by technology

While finding that this type of material has a higher capacity than graphite-based negative electrode materials, the researchers also found that there is a huge volume change during repeated cycles, which leads to the failure of battery cycle performance, thus limiting its use as a lithium-ion battery negative electrode alone. The application of materials affects its wide application. Researchers have been committed to replacing graphite anode materials with silicon, improving the capacity of lithium-ion batteries, and solving the problem of volume expansion of silicon in the process of charging and discharging has become the focus of research and development.