The market space of the lithium ion battery anode industry continues to expand with the increasing demand for lithium batteries. At present, the lithium ion battery anode is imainly artificial graphite and natural graphite, and the development trend is to dope silicon into the graphite anode to form a silicon-based anode with higher energy density.
1.The negative electrode material is mainly artificial graphite
Artificial graphite is becoming more and more important in lithium ion battery anode.
1. The lithium ion battery anode is an important part
Lithium-ion batteries are mainly composed of positive electrodes, negative electrodes, separators, electrolytes, and battery shells. Nowadays, the positive active materials are mainly ternary and lithium iron phosphate, and the negative active materials are graphite or carbon-silicon materials with similar graphite structure. It is divided into steel shell (square type is rarely used), aluminum shell, nickel-plated iron shell (used for cylindrical batteries), aluminum-plastic film (soft packaging), and battery cap (positive and negative terminals).
2. Artificial graphite is the mainstream of lithium ion battery anode
The negative electrode material is the main body of lithium ion battery to store lithium, so that lithium ions are inserted and extracted during the charging and discharging process. Negative materials are generally divided into carbon-based negative electrodes and non-carbon-based negative electrodes, among which carbon-based negative electrodes can be divided into graphite, hard carbon, and soft carbon negative electrodes.
Graphite can be divided into artificial graphite, natural graphite, composite graphite, and mesophase carbon microspheres; non-carbon-based negative electrodes include lithium titanate, tin alloy negative electrodes, silicon-based negative electrodes, etc.
3. Artificial graphite has high cost performance
Artificial graphite material has high cost performance. Artificial graphite has the advantages of high initial efficiency, long service life, stable structure and low cost. After years of development, related technologies and supporting processes have matured, becoming the most widely used and technologically mature negative electrode material now.
And it is the current mainstream route in the negative electrode industry. The negative electrode material is mainly artificial graphite, which accounts for about 10% of the total cost of lithium-ion batteries, usually less than 15%. Other parts such as the positive electrode material account for more than 40%, the electrolyte is 10% to 20%, and the diaphragm is 20% to 30%.
4. Diverse process flow of lithium ion battery anode materials
The production process of artificial graphite is mainly divided into four major links of crushing, granulation, graphitization and screening, with nearly ten small processes. Crushing is through mechanical impact, shearing and surface modification, and finally achieves the goal of forming and functionalizing the powder precursor. Granulation is adding raw and auxiliary materials of different particle sizes into the reaction kettle, and at a certain temperature and stirring speed, make the agglomeration of primary particles occur and composite into secondary particles.
Graphitization refers to the rearrangement and regularization of the lattice structure of the material through high-temperature heat treatment. The final screening mainly includes sequentially sending the agglomerated graphite after high-temperature treatment to the crusher Disperse, then enter the mixer for stirring and mixing at room temperature, and accordingly enter the ultrasonic vibrating screen to screen out the particles and sundries with excessive particle size in order to separate to form the final product.
2. The market space for lithium ion anode materials is broad
Because of the popularity of anode material, the market space is becoming broader.
1. Chinese lithium ion battery anode material shipments climbed
In 2021, the anode material market size around the world is expected to exceed 20 billion RMB. Driven by the goal of carbon neutrality, governments around the world have increased the popularity of new energy vehicles and promoted the electrification of vehicles. The sales of new energy vehicles have continued to grow, and the output of lithium-ion batteries has increased year by year, driving the market for anode materials to continue to expand.
From 2015 to 2020, the market scale of anode materials in the world continued to grow, with a 5-year compound growth rate of 19.76%. In 2020, the anode material market scale around the world will reach 19.39 billion RMB, and it is expected to reach 24 billion RMB in 2021.
2. China is the main source of lithium ion battery anode materials
China is the main producer of lithium ion battery anode. In 2021, the world’s output of anode materials will be 882,700 tons, mainly produced by China, South Korea and Japan. Among them, Chinese output will be as high as 815,900 tons, accounting for 92%, and it is the main source of anode materials.
3. Q1 lithium ion battery anode materials plan to increase production capacity by more than 2.7 million tons
Enterprises in the negative electrode industry have increased investment in new production capacity. In 2021, due to the shortage of graphitization production capacity and the continuous increase in downstream market demand, the price of graphitization will rise, and enterprises from other industries will enter the bureau to build new production lines. RMB.
There may be a structural excess of lithium ion battery anode material capacity. According to the forecast, by 2025, the major application scenarios will generate a total demand of 1,800GWh. If 1GWh power battery needs 13-14 million tons of anode materials, the above-mentioned 2.7 million tons of production capacity can meet the battery capacity demand of about 1928GWh-2076GWh .
When the graphitization capacity is gradually released, the market competition will further intensify. At the same time, due to the existence of technical, customer and capital barriers in the anode material industry, new companies entering the anode material industry will face more intense industry competition, and there is a greater possibility of subsequent idle production capacity.
3. Overview of upstream, middle and downstream of lithium ion battery anode materials
Let’s have a look at this!
1. Upstream:high prices of coke raw materials
Petroleum coke prices continued to rise. At the end of 2021, affected by the policy, the price of petroleum coke will drop from RMB 2,871/ton to RMB 2,748/ton. From January 2022 to April 2022, coupled with factors such as the Winter Olympics and the epidemic, the operating rate of petroleum coke will be low and production capacity will be low. Restricted, resulting in insufficient supply, and at the same time, strong market demand for petroleum coke downstream anode materials, resulting in a continuous rise in prices, rising to 5,094 RMB / ton by April 2022.
2. Midstream:The market share of artificial graphite will reach 84%
The shipments of anode materials have grown rapidly, and the growth rate of artificial graphite and silicon-based anodes is relatively high. From 2015 to 2021, the total shipments of anode materials increased from 74,300 tons to 720,000 tons, with a compound annual growth rate of 46%, and the overall upward trend was significant.
Among them, artificial graphite is mainly used in the power battery market and high-end battery market because of its relatively superior cycle performance and safety performance. The cargo volume increased from 46,000 tons to 604,800 tons, with a six-year compound growth rate of 53.6%. As a key research direction in the future, silicon-based anodes have been piloted in a small range, and the shipment volume has increased from 0.3 million tons to 11,000 tons, with a six-year compound growth rate of 82%.
The market share of artificial graphite is increasing year by year, while the market share of natural graphite is shrinking. From 2015 to 2021, the market share of artificial graphite has increased year by year, from 61% to 84%, and it is the most important anode material, while the market share of natural graphite has been shrinking year by year, from 29.6% to 14%. In 2021, the proportion of silicon-based anodes is only 1.5%.
3. Downstream: the rapid development of the world’s lithium-ion battery industry
The world’s lithium-ion battery industry is developing rapidly. Benefiting from the widespread popularity of lithium-ion batteries in the downstream consumer battery market and the large-scale application of the power battery market, the market size of lithium-ion batteries all around the world has maintained rapid growth since 2015.
At the same time, driven by the goal of “carbon neutrality”, governments of various countries have introduced new policies to increase subsidies for new energy vehicles again, and sales of new energy vehicles have continued to grow, driving the simultaneous growth of lithium-ion battery shipments. From 2015 to 2020, the world’s lithium-ion battery shipments increased from 100.8GWh to 294.5GWh, with an annual growth rate higher than 15%.
By 2021, shipments have reached 562.4GWh, a year-on-year increase of 91%, and a six-year compound growth rate of 33.2%. According to forecasts, the compound growth rate of lithium-ion battery shipments in the world will reach 25.6% before 2030, and the total shipments may be close to 5TWh by 2030.
Chinese lithium-ion shipments account for more than 50% of the world’s shipments. According to statistics, Chinese lithium-ion battery output has ranked first in the world for ten consecutive years. From 2015 to 2021, Chinese lithium-ion battery shipments will increase from 46GWh to 327GWh, a year-on-year increase of 129% in 2021, and a six-year compound growth rate of 38.7%. In 2021, Chinese lithium-ion battery shipments will account for 58.1% of the world’s lithium-ion battery shipments, making it one of the most important producers of lithium-ion batteries.
4. Silicon-based lithium ion battery anode is the future development direction
There is no doubt that silicon-based lithium ion battery anode has great potential to develop.
1. Silicon-based lithium ion battery anode is the future development direction
The specific capacity of the lithium ion battery anode for electric vehicles needs to reach 2000mAh/g, the service life should be more than 15 years, and it should meet the cycle requirements of 1000 cycles. In the current lithium-ion battery system, the positive electrode has been upgraded from cobalt and lithium manganate to lithium iron phosphate and ternary materials, while the theoretical gram capacity of graphite in the negative electrode material system is 372mAh/g. Approaching the theoretical capacity, the development of new anode material systems urgently needs to be solved.
2. Si-based anode technology is not yet mature
Silicon-oxygen and silicon-carbon anode materials are currently the mainstream of silicon-based anode materials. According to the difference of the dispersion matrix, the next-generation silicon-based anode materials with high capacity that are most likely to achieve large-scale applications in the future mainly include three categories of silicon-oxygen, silicon-carbon and silicon-alloy anode materials, silicon-carbon composite anode materials and silicon-oxygen anode materials. The technology of the material is relatively mature and the comprehensive electrochemical performance is better. It is the most mainstream silicon-based anode material now.
The silicon carbon anode material is prepared from nano-silicon and matrix material through a granulation process to form a precursor, and then undergoes surface treatment, sintering, pulverization, screening, demagnetization and other processes. Currently, the commercial application capacity of silicon carbon anode is below 450mAh/g, and the cost is low. Although the first effect is relatively high, the cycle life is poor, and it is mainly used in the 3C digital field.
The silicon-oxygen of lithium ion battey anode material is prepared by synthesizing pure silicon and silicon dioxide into silicon monoxide to form a silicon-oxygen negative electrode material precursor, which is then prepared through the processes of pulverization, classification, surface treatment, sintering, sieving, and demagnetization.
At the moment, the commercial application capacity is mainly 450-500mAh/g, and the cost is relatively high. Although the first effect is relatively low, the cycle performance is relatively good. It is mainly used in the field of power batteries. Tesla uses silicon-oxygen negative electrode mixed with artificial graphite.
3. Problems in the large-scale commercialization of silicon-based lithium ion battery anode
The pulverization of the material and the destruction of the electrode caused by the expansion. During the charging and discharging process, silicon and lithium will undergo an alloying reaction, and the volume of silicon will expand by 100% to 300%. Cracks until pulverized, destroying the contact between the electrode material and the current collector, making the active material detach from the pole piece, which will cause a rapid decay of the battery capacity;
Then, the expansion will generate a lot of stress inside the battery, forming a squeeze on the pole piece. With multiple cycles, there is a risk of the pole pieces breaking. This stress may also reduce the internal porosity of the battery and the mobility of lithium ions, leading to the precipitation of lithium metal and affect the safety of the battery.
4. Modification is a key technology of silicon-based of lithium ion battery anode materials
Nanoscale structurally alleviates the swelling problem. The silicon structure can be divided into zero-dimensional, one-dimensional, two-dimensional and three-dimensional in morphology. The zero-dimensional silicon nanostructure is mainly dense, porous and hollow, which avoids the pulverization of the silicon anode during the lithiation process, significantly improves the cycle stability of the silicon anode, and alleviates the overall destruction of the silicon anode. The one-dimensional silicon nanostructure can form a stable SEI layer on the outer surface, and the free space in the silicon shell can effectively prevent mechanical fracture caused by volume expansion.
However, the electrode fabrication process is different from the current commercial fabrication method, and the development cost is a practical problem that must be resolved in industrialization. Problem: The two-dimensional silicon nanostructure is beneficial to suppress the volume expansion and increase the contact area with the electrolyte, but it has not yet been applied, and it needs to face the problems of low energy density and increased production cost. The three-dimensional silicon nanostructure solves the problems of electrolyte contact area and volume expansion accommodation space, and its silicon material has higher electrode density and structural integrity.