Main content:
Lithium batteries, as the core of modern energy storage, are closely related to the performance of their materials. As the market demand for high-energy-density batteries continues to grow, the limitations of traditional graphite anode materials are becoming increasingly apparent. In contrast, silicon-based anode materials, with their superior theoretical specific capacity and fast-charging performance, are emerging as the new trend in the development of lithium battery anode materials.
This article will explore the advantages and challenges of silicon-based anode materials, as well as their development trend in the future lithium battery industry.
Definition of lithium battery anode materials
Lithium battery anode materials are one of the key components of lithium-ion batteries, accounting for about 10% of the cost of a lithium battery. The anode materials in lithium batteries store and release energy, primarily affecting the first efficiency and cycle performance of the battery. Lithium battery anode materials are mainly divided into two categories: carbon materials and non-carbon materials.
Carbon Materials: These include natural graphite, artificial graphite, mesocarbon microbeads, hard carbon, soft carbon, etc. These materials are widely used due to their low lithium intercalation potential, high theoretical specific capacity, and environmental friendliness.
Non-Carbon Materials: Such as silicon-based materials, tin-based materials, lithium titanate, etc. These materials are hotspots in research because of their high energy density and specific electrochemical properties.
Performance comparison between silicon-based and graphite anode materials
Advantages:
Silicon-based anode materials: They have a high theoretical specific capacity, capable of storing more lithium ions, thereby providing higher energy density at the same weight. This significantly enhances the battery's endurance and overall performance. The high specific capacity of these materials makes them an ideal choice for future battery high energy density.
Artificial graphite anode materials: These have mature technology and supporting processes with good cycle performance, maintaining stable capacity and performance over multiple charge-discharge cycles. Although their specific capacity is not as high as that of silicon-based materials, artificial graphite remains the mainstream choice for lithium-ion battery anode materials due to its stable cycle performance and mature manufacturing processes.
Natural graphite anode materials: These also have mature technology and supporting processes with low cost. Natural graphite possesses good conductivity and reversible lithium-ion intercalation/de-intercalation capability, allowing it to maintain stable performance over multiple charge-discharge cycles. Compared to artificial graphite, natural graphite is more cost-competitive.
Disadvantages:
Silicon-based anode materials: The technology and supporting techniques are not yet mature, and the costs are high. During charge and discharge, silicon-based materials undergo significant volume expansion and contraction, which increases the stress on the battery structure, thereby affecting its cycle stability. Moreover, the relatively low conductivity of silicon-based materials further limits their performance in high-rate applications.
Natural graphite anode materials: They have low specific battery capacity, and their rate performance is not ideal, meaning that under high-rate charge-discharge conditions, the battery's output power and efficiency can be affected.
Natural graphite anode materials: Their specific capacity has reached its limit, and they have poor cycle and rate performance, with lower safety. The safety of natural graphite materials is also questionable, especially under extreme operating conditions, where instability may occur. However, they still have value in the mid-to-low-end market.
Overcapacity of Traditional Graphite Anode Materials
The global market for lithium battery anode materials is expanding rapidly at a growth rate of 21%, with the market size expected to exceed 4 million tons by 2030. The demand for new anode materials such as silicon-based materials is expected to grow even faster in the future.
Currently, anode materials are primarily based on graphite anodes, which have developed relatively maturely. China, as the world's largest producer of anode materials, faces fierce competition, and due to the advanced planning of production capacities by various companies, there is a short-term capacity shortage but a long-term oversupply of low-end capacity, leading to industry consolidation.
Under the advanced planning of capacities, the industry's average capacity utilization rate is around 50%, and it is expected that capacity will significantly ramp up over the next decade, with production scale already surpassing the volume required for power batteries. In the future, the industry will face a significant oversupply.
Silicon-based anodes: the future trend of battery anode materials
Silicon-based anode materials are gradually replacing graphite anodes, becoming the new "favorite" in lithium battery anodes. The energy density of graphite anodes has reached its limit, and in the face of anxiety over electric vehicle range and charging, the next generation of anode materials, "silicon-based anodes," is becoming an inevitable trend in lithium battery development due to their high specific capacity and excellent fast-charging performance. There are three main advantages of silicon-based anodes over graphite anodes:
1.High theoretical specific capacity, over 10 times that of traditional graphite anodes
The theoretical specific capacity of graphite materials is relatively low, with a maximum theoretical value of 372mAh/g, currently reaching 360mAh/g.
Silicon materials have a theoretical specific capacity of 4200mAh/g, more than 10 times that of graphite materials, making it the highest known specific capacity lithium battery anode material.
2.Excellent fast-charging performance, meeting urgent current needs
Silicon materials can provide lithium ions with channels for intercalation and de-intercalation from all directions, allowing silicon-based anodes to meet the high-rate performance requirements needed for fast charging while maintaining high specific capacity.
3.Abundant silicon element reserves, cost advantage over graphite
Compared to graphite, silicon is more abundant in the Earth's crust and is relatively inexpensive. In the long run, silicon-based anodes are an effective choice for cost reduction and efficiency improvement in lithium batteries.
At the same time, solid-state batteries are globally recognized as the next generation of lithium batteries, with various governments racing to develop them. Silicon-based anodes are the preferred new anode material for solid-state batteries. The accelerated development of solid-state batteries will significantly increase the demand for silicon-based anodes. Driven by global policies and strong demand from electric vehicles, energy storage, and other industries, the shipment volume of solid-state batteries is expected to achieve exponential growth, reaching 614 GWh by 2030, with a compound annual growth rate of over 150%.
As a major player in the new energy sector, China is also strongly supporting the development of solid-state batteries through policies and funding. Additionally, the rapid development of electric vehicles and the low-altitude economy in China has accelerated the commercialization of solid-state batteries.
By 2030, the global UAM2 market is expected to reach $2 billion, with solid-state batteries accounting for 18.5% of the value in eVTOLs. As a representative of new productivity, the low-altitude economy will drive the rapid development of solid-state batteries.
Under the trends of policy and industry-driven growth in all solid state battery, the silicon-based anode material market will also grow rapidly, becoming a new demand point for lithium battery anodes in the future. Therefore, driven by power batteries, consumer batteries, and overseas markets, the global demand for silicon-based anodes is expected to reach 3 million tons by 2030, with a market size exceeding 120 billion yuan and a compound annual growth rate of 40% over the next five years.
Conclusion
Silicon-based anode materials, with their high specific capacity, excellent fast-charging performance, and abundant resource reserves, are gradually replacing traditional graphite materials, becoming a key choice for future lithium battery anode materials.
With the accelerated development of solid-state batteries and the increasing demand for high-performance batteries in the market, silicon-based anode materials are expected to dominate the future lithium battery industry, pushing lithium battery technology to new heights.
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