What is the future trend and development of the lithium battery anode material industry?

Industry Trends

1. High energy density and fast charge are future technology trends

2. Policies and markets require high-energy fast charge technology solutions

In terms of national policies, the four ministries and commissions, such as the Ministry of Industry and Information Technology, clearly stated in the Action Plan for Promoting the Development of Automotive power battery Industry: In 2020, the specific energy of lithium-ion battery cells is >300Wh/kg, and the system specific energy is 260Wh/kg.

The performance of graphite anode materials is close to its theoretical limit, and the technical solution of graphite materials as anodes cannot meet this requirement.

In 2018, the "Notice on Adjusting Financial Subsidies for the Promotion and Application of New Energy Vehicles", the financial subsidies corresponding to the battery unit's specific energy, cruising range and other performance requirements are moving upwards, the battery performance requirements are increased, and the industry is encouraged to develop high energy density batteries solution. In terms of market customer demand, lithium battery charging convenience and cruising range are important factors affecting customer experience.

The average cruising range of pure electric passenger car models in the "Recommended Models for New Energy Vehicle Promotion and Application (3rd Batch of 2018)" has exceeded 350km. However, the average new energy vehicle charging time is about 5-8 hours, and the fast charging time is about 1-2 hours.

Compared with traditional energy vehicles, new energy vehicles have much room for improvement in terms of ease of use, especially in terms of high energy density and fast charge performance of batteries.

Lithium titanate still occupies a seat, excellent fast charge performance

Lithium titanate has excellent fast charge performance. Lithium titanate has a three-dimensional lithium ion diffusion channel peculiar to the spinel structure, and thus has excellent power characteristics. The diffusion coefficient of lithium ions in lithium titanate crystals is 2x10-8cm2/s, which is an order of magnitude higher than that of graphite anodes. The charging rate of lithium titanate battery can reach 10-20C, while the charging magnification of ordinary graphite anode material is only 2-4C.

Lithium titanate is widely used in electric buses and energy storage. Lithium titanate battery has high safety, long cycle life, wide operating temperature range, and can be quickly charged and discharged. Therefore, it is used in electric commercial vehicles (bus, rail transit, etc.), energy storage market (frequency modulation, power grid quality, wind farm, etc.) and industry. The field (port machinery, forklifts, etc.) is widely used.

Zhuhai Yinlong, a domestic new energy vehicle manufacturer, also uses lithium titanate as a negative battery technology solution.

Silicon-carbon composites have high energy density and will become the future direction of anode materials.

The silicon material has a high specific capacity and can be quickly charged, which has the most promising prospects. The theoretical energy density of graphite is 372mAh/g, while the theoretical energy density of silicon exceeds 10 times, up to 4200mAh/g. The use of silicon materials as battery anodes to increase battery energy density has become one of the recognized directions in the industry.

China's negative electrode material manufacturer Betray's silicon-carbon composite anode material has been mass-produced, and the customer is Samsung of South Korea.

The mass production of silicon materials still has bottlenecks, and the silicon-carbon composite trend is the trend.

The bottleneck in the use of silicon materials is the poor cycle performance: the high expansion ratio of silicon particles in the deintercalation of lithium (silicon negative charge and discharge expansion up to 360%, while ordinary graphite is only 10%) causes the negative electrode to decay rapidly during the cycle The continuous growth of the SEI film on the surface of the silicon particles causes irreversible consumption of the electrolyte and lithium ions.

At present, a relatively mature technical solution is to use a carbon material having a small volume effect and good cycle stability as a carrier. And a silicon material having a high specific capacity is incorporated as a main active body to synthesize a silicon carbon composite material. Silicon-carbon composites can have the negative effect of reducing the volume expansion of silicon during charge and discharge.

The silicon carbon composite process is coated, doped and embedded. Tesla uses a carbon-coated sulphide solution to apply the silicon-carbon composite material to the production model Model3 by adding 10% silicon-based material to the artificial graphite. The battery has an energy density of 300wh/kg and a battery capacity of 550mAh/g or more.

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