How to solve the technical and safety problems of ternary materials? -Lithium - Ion Battery Equipment
In a narrow sense, ternary materials refer to stoichiometric nickel-cobalt-manganese three-component layered cathode materials. This type of material was first developed by Chinese scholar Liu Zhaolin in 1999 at the Institute of Materials Research and Engineering (IMRE) affiliated to A-Star in Singapore. ) was reported when I was working on it. Since then, many international research groups have conducted very detailed and in-depth research on this series of materials.
In a broad sense, the scope of ternary materials is relatively wide, and multi-element layered materials with non-stoichiometric lithium content and wide components can be included in this category.
Generally speaking, it is internationally recognized that the two research groups of Tsutamu Ohzuku from Osaka City University in Japan and J.R. Dahn from Dalhousie University in Canada have done the most in-depth and comprehensive research on ternary materials, and their research results have also had a wide impact on the industry. . Argonne National Laboratory (ANL) in the United States also has in-depth basic research on ternary materials, but its research results have relatively little impact on the industry.(Lithium - Ion Battery Equipment)
Early research on NMC mainly focused on the synthesis process, electrochemical properties, crystal structure changes and reaction mechanism of materials. In recent years, the basic research on NMC has slowed down significantly, and people have paid more attention to the innovation of material production processes and electrochemistry. Issues such as performance optimization, safety, composite ternary materials and the application of ternary materials under high voltage.
What the author wants to point out here is that because the American 3M Company was the first to apply for patents related to ternary materials, and 3M named ternary materials in the order of nickel manganese cobalt (NMC), so ternary materials are generally called NMC internationally. .
However, due to the pronunciation habit in China, it is generally called nickel cobalt manganese (NCM), which leads to misunderstandings about ternary material models, because the names of ternary materials such as 333, 442, 532, 622, 811, etc. are all named after NMC. named in order. BASF, on the other hand, deliberately called the ternary material NCM because it purchased relevant patents from the Argonne National Laboratory (ANL) in the United States. In order to show its "difference" from 3M and expand the Chinese market.
NMC actually combines the advantages of LiCoO2, LiNiO2 and LiMnO2. Due to the obvious synergistic effect between Ni, Co and Mn, the performance of NMC is better than that of single-component layered cathode materials. It is considered to be one of the most promising new cathode materials.
The three elements have different effects on the electrochemical properties of the material. Generally speaking, Co can effectively stabilize the layered structure of the ternary material and suppress the mixing of cations, improve the electronic conductivity of the material and improve the cycle performance. However, the increase in the Co ratio causes the unit cell parameters a and c to decrease and c/a to increase, resulting in a decrease in capacity.
The presence of Mn can reduce costs and improve the structural stability and safety of the material. However, excessive Mn content will reduce the gram capacity of the material, and the spinel phase will easily appear and destroy the layered structure of the material. The presence of Ni increases the unit cell parameters c and a and decreases c/a, which helps to increase the capacity. However, if the Ni content is too high, it will cause a mixing effect with Li+, resulting in deterioration of cycle performance and rate performance, and the pH value of high-nickel materials will be too high, affecting practical use.
In ternary materials, depending on the ratio of each element, Ni can have a valence of +2 and +3, Co is generally considered to have a valence of +3, and Mn has a valence of +4. The three elements play different purposes in the material. When the charging voltage is lower than 4.4V (related to the metal lithium negative electrode), it is generally considered that the important thing is Ni2+ participating in the electrochemical reaction to form Ni4+; continue charging and Co3+ participating in the reaction at a higher voltage. Oxidized to Co4+, Mn is generally considered not to participate in electrochemical reactions.
Ternary materials can be divided into two basic series according to their components: low cobalt symmetrical ternary material LiNixMnxCo1-2xO2 and high nickel ternary material LiNi1-2yMnyCoyO2. The phase diagram of the ternary material is shown in the figure above. In addition, there are some other components, such as 353, 530, 532 and so on.
The molar ratio of the two metal elements Ni/Mn in the symmetrical ternary material is fixed at 1 to maintain the valence balance of the ternary transition metal oxide. The representative products are the 333 and 442 series ternary materials. This component series Within the scope of 3M patent protection in the United States.
This type of material has a relatively complete crystal structure due to its low Ni content and high Mn content, so it has the potential to develop towards high voltages. The author has discussed it in detail in the article "Discussion on the Industrial Development of Cathode Materials for Consumer Electronics Lithium Batteries".
It can be seen from the chemical formula of high nickel ternary NMC that in order to balance the chemical valence, Ni in high nickel ternary has both +2 and +3 valences, and the higher the nickel content, the more +3 valence Ni, so the high nickel ternary The crystal structure is not as stable as symmetrical ternary materials. Other components outside these two series are generally developed to circumvent the patents of 3M or ANL, Umicore, and Nichia. For example, the 532 component was originally a stop-gap measure by SONY and Panasonic to circumvent 3M's patent, but now NMC532 has become the best-selling ternary material in the world.
Ternary materials have a higher specific capacity, so the energy density of a single cell is greatly improved compared to LFP and LMO batteries. In recent years, the research and industrialization of ternary material power lithium batteries have made great progress in Japan and South Korea. The industry generally believes that NMC power lithium batteries will become the mainstream choice for electric vehicles in the future.
Generally speaking, based on safety and cycle considerations, ternary power lithium batteries mainly use 333, 442 and 532 series with relatively low Ni content. However, due to the increasingly higher requirements for energy density of PHEV/EV , 622 is also receiving more and more attention in Japan and South Korea.
The core patents of ternary materials are mainly in the hands of 3M Company of the United States. Argonne National Laboratory (ANL) has also applied for some patents on ternary materials (some of which are included in lithium-rich manganese-based layered solid solutions), but the industry generally believes that they are The actual significance is not as good as 3M.
The largest producer of ternary materials in the world is Belgium's Umicore, and Umicore and 3M have formed an industry-research alliance. In addition, South Korea's L&F, Japan's Nichia (Nichia), and Toda Kogyo (Toda Industries) are also important international ternary material manufacturers, while Germany's BASF is a newly added ternary upstart.
It is worth mentioning that the four major battery cell manufacturers in the world (SONY, Panasonic, SamsungSDI and LG) have a considerable proportion of inhouse production in terms of ternary materials and lithium cobalt oxide cathode materials. This is also the proportion of these four major manufacturers. This is an important reflection of the significant technological lead of other battery cell manufacturers in the world.
1. Important issues and modification methods of ternary materials
At present, important problems in the application of NMC to power lithium batteries include:
(1) Due to the cation mixing effect and the change of the material surface microstructure during the first charging process, the first charge and discharge efficiency of NMC is not high, and the first efficiency is generally less than 90%;
(2) The safety of the ternary material battery cell is serious due to serious gas production, and high-temperature storage and cyclicity need to be improved;
(3) The lithium ion diffusion coefficient and electronic conductivity are low, making the rate performance of the material less than ideal;
(4) Ternary materials are secondary spherical particles formed by agglomeration of primary particles. Since the secondary particles will break under high compaction, the compaction of the ternary material electrode is limited, which also limits the energy of the battery core. further increase in density. In response to the above problems, modification measures currently widely used in the industry include:
Heteroatom doping. In order to improve the required properties of the material (such as thermal stability, cycle performance or rate capability, etc.), doping modification research is usually carried out on cathode materials. However, doping modification can often only improve a certain aspect or part of the electrochemical performance, and is often accompanied by a decrease in some other aspect of the material's performance (such as capacity, etc.).
NMC can be divided into cation doping, anion doping and composite doping according to different doping elements. Many cation dopings have been studied, but those with practical effects are limited to Mg, Al, Ti, Zr, Cr, Y, and Zn. Generally speaking, proper cation doping of NMC can suppress the cation mixing of Li/Ni and help reduce the first irreversible capacity.
Cation doping can make the layered structure more complete, thereby helping to improve the rate capability of NMC and also improve the stability of the crystal structure, which has an obvious effect on improving the cycle performance and thermal stability of the material.
Anion doping mainly involves doping F atoms with a radius similar to that of oxygen atoms. Doping an appropriate amount of F can promote the sintering of the material and make the structure of the cathode material more stable. F doping can also stabilize the interface between the active material and the electrolyte during cycling, improving the cycling performance of the cathode material.
Mixed doping generally involves doping NMC with F and one or several cations at the same time. The most widely used ones are Mg-F, Al-F, Ti-F, Mg-Al-F, and Mg-Ti-F. kind of combination. Mixed doping has significantly improved the cycle and rate performance of NMC, and the thermal stability of the material has also been improved to a certain extent. It is an important modification method currently used by mainstream international cathode manufacturers.
The key to NMC doping modification lies in what elements are doped, how to do it, and the amount of doping, which requires manufacturers to have certain research and development capabilities. The heteroatom doping of NMC can be done by wet doping during the precursor co-precipitation stage or dry doping during the sintering stage. As long as the process is done properly, good results can be achieved. Manufacturers must choose appropriate technical routes based on their own technology accumulation and economic conditions. As the saying goes, all roads lead to Rome, and the route that suits them is the best technology.
Surface covering. NMC surface coatings can be divided into two types: oxide and non-oxide. The most common oxides include MgO, Al2O3, ZrO2 and TiO2. Common non-oxides include AlPO4, AlF3, LiAlO2, LiTiO2, etc. The main purpose of inorganic surface coating is to mechanically separate the material and the electrolyte, thereby reducing side reactions between the material and the electrolyte, inhibiting the dissolution of metal ions, and optimizing the cycle performance of the material.
At the same time, inorganic coating can also reduce the collapse of the material structure during repeated charge and discharge processes, which is beneficial to the cycle performance of the material. NMC surface coating is more effective in reducing the residual alkali content on the surface of high-nickel ternary materials. This issue will be discussed later.
Similarly, the difficulty of surface coating lies first in choosing what kind of coating, and then in what kind of coating method and amount of coating. Coating can be done by dry coating or wet coating in the precursor stage. This requires manufacturers to choose the appropriate process route according to their own conditions.
Optimization of production processes. Improving the production process is important to improve the quality of NMC products, such as reducing the surface residual alkali content, improving the integrity of the crystal structure, reducing the content of fine powder in the material, etc. These factors have a greater impact on the electrochemical performance of the material. For example, appropriately adjusting the Li/M ratio can improve the rate performance of NMC and increase the thermal stability of the material. This requires manufacturers to have a considerable understanding of the crystal structure of ternary materials.
2. Precursor production of ternary materials
Compared with the production process of several other cathode materials, NMC has a big difference in its unique precursor co-precipitation production process. Although the use of liquid phase methods to produce precursors is becoming more and more common in the production of LCO, LMO and LFP, especially in the production of high-end materials, for most small and medium-sized companies, the solid phase method is still the only choice for these materials. mainstream technology.
However, for ternary materials (including NCA and OLO), the liquid phase method must be used to ensure the uniform mixing of elements at the atomic level, which cannot be achieved by the solid phase method. It is precisely because of this unique co-precipitation process that the modification of NMC is easier than other cathode materials, and the effect is also obvious.
The current international mainstream NMC precursor production uses the hydroxide co-precipitation process, with NaOH as the precipitant and ammonia as the complexing agent to produce high-density spherical hydroxide precursors. The advantage of this process is that it is relatively easy to control the particle size, specific surface area, morphology and tap density of the precursor, and the reactor operation is also relatively easy in actual production. However, there is also the problem of wastewater (containing NH3 and sodium sulfate) treatment, which undoubtedly increases the overall production cost.
The carbonate co-precipitation process has certain advantages from the perspective of cost control. This process can produce particles with good sphericity even without the use of complexing agents. The most important problem in the carbonate process at present is that the process stability is poor and the product particle size is not easy to control. The impurity (Na and S) content of the carbonate precursor is higher than that of the hydroxide precursor, which affects the electrochemical performance of the ternary material, and the tap density of the carbonate precursor is lower than that of the hydroxide precursor. This is Limits the performance of NMC energy density.
The author personally believes that from the perspective of cost control and the practical application of high-specific surface area ternary materials in power lithium batteries, the carbonate process can be an important supplement to the mainstream hydroxide co-precipitation process and should attract sufficient attention from domestic manufacturers. .
At present, domestic cathode material manufacturers generally ignore the production and research and development of ternary material precursors, and most manufacturers directly outsource the precursors for sintering. What the author wants to emphasize here is that the precursor is crucial to the production of ternary materials, because the quality of the precursor (morphology, particle size, particle size distribution, specific surface area, impurity content, tap density, etc.) directly determines the final Physical and chemical indicators of sintered products.
It can be said that 60% of the technical content of ternary materials is in the precursor process, while the sintering process is relatively transparent. Therefore, whether from the perspective of cost or product quality control, ternary manufacturers must produce their own precursors.
In fact, the international mainstream manufacturers of ternary materials, including Umicore, Nichia, L&F, and TodaKogyo, all produce their own precursors and only outsource them appropriately when their own production is insufficient. Therefore, domestic cathode manufacturers must attach great importance to the research, development and production of precursors.
In a broad sense, the scope of ternary materials is relatively wide, and multi-element layered materials with non-stoichiometric lithium content and wide components can be included in this category.
Generally speaking, it is internationally recognized that the two research groups of Tsutamu Ohzuku from Osaka City University in Japan and J.R. Dahn from Dalhousie University in Canada have done the most in-depth and comprehensive research on ternary materials, and their research results have also had a wide impact on the industry. . Argonne National Laboratory (ANL) in the United States also has in-depth basic research on ternary materials, but its research results have relatively little impact on the industry.(Lithium - Ion Battery Equipment)
Early research on NMC mainly focused on the synthesis process, electrochemical properties, crystal structure changes and reaction mechanism of materials. In recent years, the basic research on NMC has slowed down significantly, and people have paid more attention to the innovation of material production processes and electrochemistry. Issues such as performance optimization, safety, composite ternary materials and the application of ternary materials under high voltage.
What the author wants to point out here is that because the American 3M Company was the first to apply for patents related to ternary materials, and 3M named ternary materials in the order of nickel manganese cobalt (NMC), so ternary materials are generally called NMC internationally. .
However, due to the pronunciation habit in China, it is generally called nickel cobalt manganese (NCM), which leads to misunderstandings about ternary material models, because the names of ternary materials such as 333, 442, 532, 622, 811, etc. are all named after NMC. named in order. BASF, on the other hand, deliberately called the ternary material NCM because it purchased relevant patents from the Argonne National Laboratory (ANL) in the United States. In order to show its "difference" from 3M and expand the Chinese market.
NMC actually combines the advantages of LiCoO2, LiNiO2 and LiMnO2. Due to the obvious synergistic effect between Ni, Co and Mn, the performance of NMC is better than that of single-component layered cathode materials. It is considered to be one of the most promising new cathode materials.
The three elements have different effects on the electrochemical properties of the material. Generally speaking, Co can effectively stabilize the layered structure of the ternary material and suppress the mixing of cations, improve the electronic conductivity of the material and improve the cycle performance. However, the increase in the Co ratio causes the unit cell parameters a and c to decrease and c/a to increase, resulting in a decrease in capacity.
The presence of Mn can reduce costs and improve the structural stability and safety of the material. However, excessive Mn content will reduce the gram capacity of the material, and the spinel phase will easily appear and destroy the layered structure of the material. The presence of Ni increases the unit cell parameters c and a and decreases c/a, which helps to increase the capacity. However, if the Ni content is too high, it will cause a mixing effect with Li+, resulting in deterioration of cycle performance and rate performance, and the pH value of high-nickel materials will be too high, affecting practical use.
In ternary materials, depending on the ratio of each element, Ni can have a valence of +2 and +3, Co is generally considered to have a valence of +3, and Mn has a valence of +4. The three elements play different purposes in the material. When the charging voltage is lower than 4.4V (related to the metal lithium negative electrode), it is generally considered that the important thing is Ni2+ participating in the electrochemical reaction to form Ni4+; continue charging and Co3+ participating in the reaction at a higher voltage. Oxidized to Co4+, Mn is generally considered not to participate in electrochemical reactions.
Ternary materials can be divided into two basic series according to their components: low cobalt symmetrical ternary material LiNixMnxCo1-2xO2 and high nickel ternary material LiNi1-2yMnyCoyO2. The phase diagram of the ternary material is shown in the figure above. In addition, there are some other components, such as 353, 530, 532 and so on.
The molar ratio of the two metal elements Ni/Mn in the symmetrical ternary material is fixed at 1 to maintain the valence balance of the ternary transition metal oxide. The representative products are the 333 and 442 series ternary materials. This component series Within the scope of 3M patent protection in the United States.
This type of material has a relatively complete crystal structure due to its low Ni content and high Mn content, so it has the potential to develop towards high voltages. The author has discussed it in detail in the article "Discussion on the Industrial Development of Cathode Materials for Consumer Electronics Lithium Batteries".
It can be seen from the chemical formula of high nickel ternary NMC that in order to balance the chemical valence, Ni in high nickel ternary has both +2 and +3 valences, and the higher the nickel content, the more +3 valence Ni, so the high nickel ternary The crystal structure is not as stable as symmetrical ternary materials. Other components outside these two series are generally developed to circumvent the patents of 3M or ANL, Umicore, and Nichia. For example, the 532 component was originally a stop-gap measure by SONY and Panasonic to circumvent 3M's patent, but now NMC532 has become the best-selling ternary material in the world.
Ternary materials have a higher specific capacity, so the energy density of a single cell is greatly improved compared to LFP and LMO batteries. In recent years, the research and industrialization of ternary material power lithium batteries have made great progress in Japan and South Korea. The industry generally believes that NMC power lithium batteries will become the mainstream choice for electric vehicles in the future.
Generally speaking, based on safety and cycle considerations, ternary power lithium batteries mainly use 333, 442 and 532 series with relatively low Ni content. However, due to the increasingly higher requirements for energy density of PHEV/EV , 622 is also receiving more and more attention in Japan and South Korea.
The core patents of ternary materials are mainly in the hands of 3M Company of the United States. Argonne National Laboratory (ANL) has also applied for some patents on ternary materials (some of which are included in lithium-rich manganese-based layered solid solutions), but the industry generally believes that they are The actual significance is not as good as 3M.
The largest producer of ternary materials in the world is Belgium's Umicore, and Umicore and 3M have formed an industry-research alliance. In addition, South Korea's L&F, Japan's Nichia (Nichia), and Toda Kogyo (Toda Industries) are also important international ternary material manufacturers, while Germany's BASF is a newly added ternary upstart.
It is worth mentioning that the four major battery cell manufacturers in the world (SONY, Panasonic, SamsungSDI and LG) have a considerable proportion of inhouse production in terms of ternary materials and lithium cobalt oxide cathode materials. This is also the proportion of these four major manufacturers. This is an important reflection of the significant technological lead of other battery cell manufacturers in the world.
1. Important issues and modification methods of ternary materials
At present, important problems in the application of NMC to power lithium batteries include:
(1) Due to the cation mixing effect and the change of the material surface microstructure during the first charging process, the first charge and discharge efficiency of NMC is not high, and the first efficiency is generally less than 90%;
(2) The safety of the ternary material battery cell is serious due to serious gas production, and high-temperature storage and cyclicity need to be improved;
(3) The lithium ion diffusion coefficient and electronic conductivity are low, making the rate performance of the material less than ideal;
(4) Ternary materials are secondary spherical particles formed by agglomeration of primary particles. Since the secondary particles will break under high compaction, the compaction of the ternary material electrode is limited, which also limits the energy of the battery core. further increase in density. In response to the above problems, modification measures currently widely used in the industry include:
Heteroatom doping. In order to improve the required properties of the material (such as thermal stability, cycle performance or rate capability, etc.), doping modification research is usually carried out on cathode materials. However, doping modification can often only improve a certain aspect or part of the electrochemical performance, and is often accompanied by a decrease in some other aspect of the material's performance (such as capacity, etc.).
NMC can be divided into cation doping, anion doping and composite doping according to different doping elements. Many cation dopings have been studied, but those with practical effects are limited to Mg, Al, Ti, Zr, Cr, Y, and Zn. Generally speaking, proper cation doping of NMC can suppress the cation mixing of Li/Ni and help reduce the first irreversible capacity.
Cation doping can make the layered structure more complete, thereby helping to improve the rate capability of NMC and also improve the stability of the crystal structure, which has an obvious effect on improving the cycle performance and thermal stability of the material.
Anion doping mainly involves doping F atoms with a radius similar to that of oxygen atoms. Doping an appropriate amount of F can promote the sintering of the material and make the structure of the cathode material more stable. F doping can also stabilize the interface between the active material and the electrolyte during cycling, improving the cycling performance of the cathode material.
Mixed doping generally involves doping NMC with F and one or several cations at the same time. The most widely used ones are Mg-F, Al-F, Ti-F, Mg-Al-F, and Mg-Ti-F. kind of combination. Mixed doping has significantly improved the cycle and rate performance of NMC, and the thermal stability of the material has also been improved to a certain extent. It is an important modification method currently used by mainstream international cathode manufacturers.
The key to NMC doping modification lies in what elements are doped, how to do it, and the amount of doping, which requires manufacturers to have certain research and development capabilities. The heteroatom doping of NMC can be done by wet doping during the precursor co-precipitation stage or dry doping during the sintering stage. As long as the process is done properly, good results can be achieved. Manufacturers must choose appropriate technical routes based on their own technology accumulation and economic conditions. As the saying goes, all roads lead to Rome, and the route that suits them is the best technology.
Surface covering. NMC surface coatings can be divided into two types: oxide and non-oxide. The most common oxides include MgO, Al2O3, ZrO2 and TiO2. Common non-oxides include AlPO4, AlF3, LiAlO2, LiTiO2, etc. The main purpose of inorganic surface coating is to mechanically separate the material and the electrolyte, thereby reducing side reactions between the material and the electrolyte, inhibiting the dissolution of metal ions, and optimizing the cycle performance of the material.
At the same time, inorganic coating can also reduce the collapse of the material structure during repeated charge and discharge processes, which is beneficial to the cycle performance of the material. NMC surface coating is more effective in reducing the residual alkali content on the surface of high-nickel ternary materials. This issue will be discussed later.
Similarly, the difficulty of surface coating lies first in choosing what kind of coating, and then in what kind of coating method and amount of coating. Coating can be done by dry coating or wet coating in the precursor stage. This requires manufacturers to choose the appropriate process route according to their own conditions.
Optimization of production processes. Improving the production process is important to improve the quality of NMC products, such as reducing the surface residual alkali content, improving the integrity of the crystal structure, reducing the content of fine powder in the material, etc. These factors have a greater impact on the electrochemical performance of the material. For example, appropriately adjusting the Li/M ratio can improve the rate performance of NMC and increase the thermal stability of the material. This requires manufacturers to have a considerable understanding of the crystal structure of ternary materials.
2. Precursor production of ternary materials
Compared with the production process of several other cathode materials, NMC has a big difference in its unique precursor co-precipitation production process. Although the use of liquid phase methods to produce precursors is becoming more and more common in the production of LCO, LMO and LFP, especially in the production of high-end materials, for most small and medium-sized companies, the solid phase method is still the only choice for these materials. mainstream technology.
However, for ternary materials (including NCA and OLO), the liquid phase method must be used to ensure the uniform mixing of elements at the atomic level, which cannot be achieved by the solid phase method. It is precisely because of this unique co-precipitation process that the modification of NMC is easier than other cathode materials, and the effect is also obvious.
The current international mainstream NMC precursor production uses the hydroxide co-precipitation process, with NaOH as the precipitant and ammonia as the complexing agent to produce high-density spherical hydroxide precursors. The advantage of this process is that it is relatively easy to control the particle size, specific surface area, morphology and tap density of the precursor, and the reactor operation is also relatively easy in actual production. However, there is also the problem of wastewater (containing NH3 and sodium sulfate) treatment, which undoubtedly increases the overall production cost.
The carbonate co-precipitation process has certain advantages from the perspective of cost control. This process can produce particles with good sphericity even without the use of complexing agents. The most important problem in the carbonate process at present is that the process stability is poor and the product particle size is not easy to control. The impurity (Na and S) content of the carbonate precursor is higher than that of the hydroxide precursor, which affects the electrochemical performance of the ternary material, and the tap density of the carbonate precursor is lower than that of the hydroxide precursor. This is Limits the performance of NMC energy density.
The author personally believes that from the perspective of cost control and the practical application of high-specific surface area ternary materials in power lithium batteries, the carbonate process can be an important supplement to the mainstream hydroxide co-precipitation process and should attract sufficient attention from domestic manufacturers. .
At present, domestic cathode material manufacturers generally ignore the production and research and development of ternary material precursors, and most manufacturers directly outsource the precursors for sintering. What the author wants to emphasize here is that the precursor is crucial to the production of ternary materials, because the quality of the precursor (morphology, particle size, particle size distribution, specific surface area, impurity content, tap density, etc.) directly determines the final Physical and chemical indicators of sintered products.
It can be said that 60% of the technical content of ternary materials is in the precursor process, while the sintering process is relatively transparent. Therefore, whether from the perspective of cost or product quality control, ternary manufacturers must produce their own precursors.
In fact, the international mainstream manufacturers of ternary materials, including Umicore, Nichia, L&F, and TodaKogyo, all produce their own precursors and only outsource them appropriately when their own production is insufficient. Therefore, domestic cathode manufacturers must attach great importance to the research, development and production of precursors.
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