Introduction to Anode Material And Its Development Trend of Power Lithium Battery
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Update time : 2023-03-31 10:24:16
With the rapid development of new energy vehicle industry, the demand for high-performance power lithium battery continues to rise, and the market demand for anode material as the core of power lithium battery is increasing day by day. In 2022, global shipments of anode materials reached 1.556 million tons, an increase of 71.9 percent over the same period last year. Among them, shipments of anode materials in China increased by 84.0 percent to 1.433 million tons.
As one of the key materials of power lithium battery, the negative electrode material accounts for about 10% of the battery cost. it is mainly composed of negative active material, adhesive and additive, which is evenly smeared on both sides of copper foil and dried and rolled. It plays a role in reversibly removing / intercalating lithium ions and storing energy, and plays a decisive role in the performance of lithium battery charge and discharge efficiency, capacity density and so on.
In fact, there are many kinds of anode materials for lithium batteries, which can be divided into two categories: carbon materials and non-carbon materials according to the active materials used.
Graphite Anode Material
Up to now, graphite has been recognized as an ideal anode material for lithium batteries, accounting for more than 95% of the market share. The negative electrode of graphite can be further divided into two categories: natural graphite and artificial graphite. In terms of gram capacity, the capacity of natural graphite is slightly higher than that of artificial graphite. The theoretical capacity of natural graphite anode material is 340-370mAh/g, and that of artificial graphite anode material is 310-360mAh/g. In terms of cycle performance, the cycle performance of artificial graphite is better than that of natural graphite. The cycle number of natural graphite is about 500 cycles, and the cycle number of artificial graphite can reach 6000 cycles. The main reason is that the particle size of natural graphite is inconsistent and there are many surface defects. therefore, it is easy to react with the electrolyte, which leads to the decline of cycle performance. From the point of view of the expansion rate, the expansion rate of natural graphite is higher than that of artificial graphite, which is mainly due to the high crystallinity of flake graphite, large unitization of lamellar structure and obvious anisotropy. Lithium intercalation and de-intercalation process produces a great change in volume. In terms of manufacturing costs and selling prices, the cost and selling price of artificial graphite are higher than those of natural graphite, mainly due to graphitization process; as far as the trend is concerned, artificial graphite accounts for 84% of the market in 2022 and 15% of the natural graphite market.
The combination of natural graphite and artificial graphite stabilizes the position of graphite anode in anode materials.
Silicon-carbon Anode Material
As the specific capacity of graphite material is close to the theoretical specific capacity limit 372mAh/g, the space for further improvement is limited, which limits the development of high-performance lithium-ion batteries. Silicon-based anode materials are regarded as the most potential next-generation anode materials because of their high theoretical capacity, low lithium intercalation potential, environment-friendly and abundant reserves.
As Tesla, BMW and other car companies announced to hold hands with 4680 series of large cylindrical batteries, large cylindrical batteries have attracted much attention from the power battery market. Silicon-based materials, as anode materials for large cylindrical batteries, are considered by the market to be the mainstream direction of the next generation of anode materials.
In the silicon-based negative electrode, in order to solve the expansion coefficient defect of elemental silicon, artificial graphite is usually added in the way of doping in the current practical application, and the mainstream technical route is silicon-carbon negative electrode and silicon oxygen / carbon negative electrode. The former refers to the mixture of nano-silicon and graphite, while the latter uses silicon oxide and graphite composite.
From the performance point of view, the first effect of silicon-carbon negative electrode is high, but the volume expansion coefficient is too large, which leads to poor cycle performance, generally at 500 to 600 cycles, which can not reach the national standard of power battery cycle of 1000 cycles; on the contrary, the first effect is relatively low, the cost is high, but the cyclicity is better.
From the market point of view, the silicon-based negative electrode is in the early stage of commercialization, the shipments and permeability are at a very low level, and the growth rate is not as fast as the overall expansion speed of the negative electrode industry. In 2021, domestic shipments of silicon-based negative electrodes are about 11000 tons. However, GGII analysis points out that in 2022, the proportion of silicon-based negative electrode in the whole anode material increases obviously, which is nearly 3 times. From the perspective of development, although the cycle performance of silicon oxide / carbon itself is better than that of silicon carbon, through carbon coating and other modification methods, it can meet the requirements of power battery in terms of cyclicity and expansion. at present, the amount of silicon-based anode materials in the market is also dominated by silicon oxygen / carbon.
However, the raw material price of silicon oxygen / carbon negative electrode is more expensive than that of silicon carbon negative electrode; in addition, the first effect of silicon oxygen / carbon negative electrode is low, which requires pre-lithiation, and pre-lithium reagent is needed for pre-lithiation. At present, the price of lithium salt is relatively high, which leads to a further increase in the cost of silicon oxygen / carbon negative electrode. In addition, due to the reaction to form lithium silicate, the silica / carbon negative electrode can inhibit its expansion, so its cycle performance is better, but in turn, it has side effects on the electrochemical performance and the overall energy density of the silicon oxygen / carbon negative electrode. Therefore, from the long-term development of new energy vehicles, silicon-carbon negative electrode has more advantages under the trend of high energy density and low cost of power lithium battery.
Lithium Battery Anode Material Supplier
Luoyang Tongrun Nano Technology Co. Ltd. (TRUNNANO) is a trusted lithium battery anode material manufacturer and Si nanopowder supplier with over 12-year-experience. We ship our goods all over the world.
If you are looking for high-quality lithium battery anode material, please feel free to contact us and send an inquiry. ([email protected])
