Future applications and trends of silicon anode materials

Anode material is one of the four key materials for lithium batteries, accounting for about 8% of the overall lithium battery manufacturing cost. The key function is to reversibly remove/embed lithium ions, which is made of active substances, binders and additives into a paste-like adhesive, then coated on both sides of the copper foil, dried and pressed. At present, graphite is the mainstream of anode materials, mainly divided into natural graphite and artificial graphite, and the proportion of graphite-based materials in the use of anode materials in China has reached 98% in 2021.

However, as the commercial graphite anode is close to the theoretical specific capacity limit of 372 mAh/g, it limits its further application. Among the known anode materials, silicon possesses a theoretical specific capacity of up to 4200mAh/g, which is more than 10 times that of graphite materials, and can provide lithium ion embedding and disembedding channels from all directions with excellent fast charging performance, so silicon anode materials are expected to become the next generation of anode materials.

Background of silicon anode material industry development

In current commercial applications, silicon anode is mainly doped into artificial graphite, with high theoretical specific capacity and lower electrochemical embedded lithium potential and excellent fast charging performance. Silicon anode has also gradually become a key material for the development of a series of new technology fields such as portable electronics, drones, new energy vehicles and energy storage battery systems.

Technology routes for the silicon anode materials industry

At present, the mainstream technology route includes silicon carbon anode and silicon oxygen anode, silicon carbon anode refers to the mixture of silicon nanoparticles and graphite materials, while silicon oxygen anode uses silicon oxide and graphite material composite. In recent years, the first time the efficiency of silicon-oxygen anode has been significantly improved through the efforts of material manufacturers, and its better integration can show the direction of the future development of silicon anode.

According to the data, in 2021, the global FPGA chip industry size of about 6.86 billion U.S. dollars, an increase of 12.8% year-on-year. With the global deployment of next-generation communication devices and emerging market areas such as artificial intelligence and autonomous driving technology demand continues to grow, FPGA market size is expected to continue to improve, and by 2025 the global market size will reach 12.58 billion U.S. dollars.

Silicon anode industry market size

According to estimates, the global silicon anode shipments are expected to reach 149,000 tons in 2025, and the penetration rate will reach 5.4%. At present, lithium batteries are mainly used in power batteries, consumer batteries and energy storage batteries. Taking power battery as an example, measuring the different silicon based demand of cylindrical battery and non-cylindrical battery, considering the different use ratio of silicon anode in different applications, and then combining graphite negative electrode with silicon anode per GWh battery corresponding unit consumption, the global silicon anode shipment is expected to grow at an annual growth rate of more than 60%. It is expected that silicon anode will be the first to appear in high-end models.

Silicon anode industry development trends

Silicon anode replaces graphite-based anode and becomes the next generation of anode material. In terms of gram capacity, silicon anode has an absolute advantage, more than 10 times that of graphite anode. In terms of low de-lithium voltage, silicon anode replaces the traditional graphite anode material without reducing the open circuit voltage of the whole battery, thus ensuring high specific power density.

Silicone anode has better overall performance and is the next generation of high specific power silicon anode material of choice. Compared with SiC anode, Li+ in SiO anode has higher diffusion rate in SiO and shows better multiplicative performance. Also, the volume expansion during the lithium embedding process is significantly smaller than that of SiC anode, and the cycle life is longer.

Silicon anode industry drivers

The development of fast-charging technology requires rapid innovation of cell materials. Fast charging technology is the direction of progress in the development of lithium battery technology, graphite materials due to its laminar structure leads to a slow process of lithium embedded, limiting the application of lithium-ion battery fast charging, but silicon anode material through the reaction mechanism of alloying and de-alloying, can be a good solution to the fast charging process of lithium precipitation problems, effectively reducing battery safety issues.

Range anxiety drives the demand for silicon anode up. Compared with graphite anode embedded lithium storage, silicon anode material alloying lithium storage mechanism can store more lithium ions, thus giving silicon higher theoretical specific capacity (4200mAh/g), the battery energy density is relatively high, thus effectively improving the range.

Large cylindrical cells such as 4680 drive the demand for silicon anode materials. silicon anode has a very high expansion rate during charging and discharging, and the larger size of large cylindrical cells can reserve a certain space for silicon expansion to reduce the impact of expansion, while the surface of large cylindrical cells is curved, which can share the expansion pressure in multiple directions, making large cylindrical cells more suitable for silicon anode.

The scale of cost reduction drives the rapid development of silicon anode. Different silicon anode enterprises have different degrees of integration and investment amounts, but they are currently higher than graphite anode. According to the feedback of industry calculation, with the scale of silicon anode put into production, its investment amount will also gradually decline, technological progress and scale cost reduction is expected to promote the rapid development of the industry.

Competitive landscape of silicon anode industry

At present, the silicon anode market is highly concentrated, with no more than three mass-production companies and more than 20 companies in R&D and small trials. Silicon anode currently has three main types of companies: existing graphite-based anode companies, founding teams of research institutes, and battery companies or companies that have crossed over into the field. Each enterprise has done strategic layout in advance, and in the future, with the development of silicon anode market, the competition track is expected to become more and more intense.