Application of Silicon-based Negative Electrode Materials in Lithium-ion Batteries

With the vigorous development of new energy vehicles, energy storage and other markets, the market scale and technical level of lithium batteries and anode materials have been continuously improved. At present, the specific capacity of commercial graphite anode materials approaches the theoretical specific capacity of graphite materials, and the commercial application of silicon-based anode materials has been further accelerated.

Silicon-based anode materials have become the research focus of lithium-ion battery anode materials because of their extremely high theoretical specific capacity. The theoretical specific capacity of silicon anode material is much higher than that of commercial graphite anode material, and its working voltage is moderate, which makes silicon-based anode material have significant advantages in improving battery energy density. However, the excessive volume expansion and contraction of silicon during charging and discharging leads to the cracking and crushing of materials and the continuous thickening of SEI film, which seriously affects the cycle stability and rate performance of the battery.

In order to solve the defects of silicon-based anode materials in the application of lithium-ion batteries, researchers put forward a variety of technical routes, including nano-technology, composite technology, structural design, surface modification, electrolyte optimization, pre-lithiation, porous silicon and alloy silicon.

These technical routes cover all stages from laboratory research to industrial application. Nano-materials and composite materials are used to alleviate the volume expansion problem, structural design and surface modification are used to improve the conductivity and stability, and the overall performance of the battery is enhanced by optimizing the electrolyte system. Pre-lithiation technology can improve the initial coulombic efficiency, porous silicon structure is helpful to alleviate the volume change, while alloy silicon can provide higher capacity and stability. The comprehensive application of these technical routes is expected to achieve high performance, long life and low cost of silicon-based anode materials, and promote their wide popularization in practical applications.

At present, silicon carbon material and silicon oxide material are two main technical routes of silicon-based anode.

Among them, silicon-carbon anode material is famous for its high first coulombic efficiency, but its cycle life needs to be improved. By realizing the nanocrystallization of silicon materials, the problems of expansion and breakage during charging and discharging can be reduced, thus further enhancing its cycle life. In contrast, the main advantage of silicon-oxygen anode material is its excellent cycle stability, although the first effect is low. However, by using pre-lithiation and other technical means, its first effect can be effectively improved.

In terms of commercial application, at present, the main commercial applications of silicon-based anode materials are carbon-coated silicon oxide, nano-silicon carbon, silicon nanowires and amorphous silicon alloys. Among them, carbon-coated silica and nano-silicon carbon have the highest degree of commercialization, and they are usually mixed into graphite in the proportion of 5%-10%. In recent years, silicon-based anode materials are gradually being industrialized.

In the field of solid-state batteries, silicon-based anode materials are considered as one of the key development directions of solid-state battery anode materials because of their high theoretical energy density, excellent fast charge-discharge performance and excellent safety performance.

Silicon-carbon materials, because of their high hardness and low grinding fineness, have very high requirements for sand mills. Yifu vertical sand mill provides a perfect solution for grinding silicon and carbon materials. Without screen structure, grinding beads as low as 0.03mm can be used, which can challenge finer grinding fineness; Vertical structure can improve grinding efficiency and narrow particle size distribution; Simplifying the production line design of the process can comprehensively improve the production line cost and production efficiency.

Yifu has rich experience and technical reserves in the field of new material grinding, and has continuously imported many high-quality sanding system solutions for the industry. Welcome customers and friends to inquire and exchange!