Why should we test the electrochemical performance of nickel oxide in alkaline electrolyte?

The author would like to point out that Sanmen is commonly known as ternary materials according to the order of nickel and cobalt (NMC) because Misan M Company applied for patents related to ternary materials earlier. In NMC, it is called Nickel Cobalt Manganese (NCM) in pronunciation habit, and the model of ternary material is misunderstood. The names of ternary materials are better than those of 3333, 442, 532, Luer, Ba and so on. BASF was named under the order of NMC, and later it bought Argonne Laboratories (ANL). Related patents show that NCM ternary material (NMC), which is different from the other three M ternary materials and intends to expand the market, actually integrates the advantages of LiCoO II and LiNiO II LiMnO II, because there is obvious synergistic effect between Ni and CoMn. The NMC performance of single-component layered polar materials has a promising application prospect. The electrochemical properties of new polar materials affect the electrochemical properties of three elemental materials. Generally speaking, the layered structure of ternary materials can be stabilized by Co energy efficiency, which can inhibit the mixed discharge of cations, improve the conductivity of materials and improve the cycle performance. The increase of Co ratio leads to the decrease of battery parameters ac and c/the increase of a leads to the decrease of capacity and Mn storage capacity. The improved material has high structural stability and safety, the content of Mn reduces the gram capacity of the material, and it is easy to produce spinel phase to destroy the layered structure of the material. Nickel storage increases the battery parameter ca, and reducing c/ A is helpful to improve the capacity. The mixed discharge effect of high Ni content and Li+ leads to poor cycling performance and high pH value of high Ni materials, which affects the practical use of ternary materials. According to the proportion of each element, it is generally recognized that Ni+II+ trivalent Co+ trivalent Mn+ tetravalent ternary materials work together. When the charging voltage is lower than 4.4 V (relative to lithium metal cathode), it is recognized that Ni+II participates in the electrochemical reaction of Ni+IV. Co 3+, which continues to be charged with higher voltage, takes part in the reaction and oxidizes Co 4 +Mn, but the ternary materials that take part in the electrochemical reaction are generally identified according to two basic series: low cobalt symmetric ternary materials LiNixMnxCo Yi-Er xO Er and high nickel ternary materials LiNi Yi-Er yMnyCoyO Er, and the molar ratio of other ternary materials Ni/Mn to the two metal elements is fixed, so as to maintain the equilibrium of ternary metal oxidation valence states. It represents the patent protection scope of US-3 M series of 33442 series ternary materials. Because of the low Ni content and high Mn content, the material has a relatively complete crystal structure and high voltage development potential. The author discusses in detail the industrialization development of electrode materials for lithium-ion batteries for consumer electronic products. In this paper, the NMC formula of high nickel ternary is discussed, and the equilibrium price of nickel and +2+ trivalent on the surface of high nickel ternary is obtained. The higher the nickel content and+trivalent nickel, the higher the crystal structure of nickel ternary. Asymmetric ternary materials are stable except for two series. Some groups generally evade 3 M or the patent distribution ratio of ANL, Umicore and Nichia. Sony's loose evasion of 3m patents should be counted. Now NMC5 3 2 is the best-selling ternary material in the world. Ternary materials have higher specific capacity than LFPLMO batteries. Compared with LFPLMO battery, the industrialization of energy density research of ternary material battery in Korea has made progress. It is generally believed in the industry that NMC battery is the mainstream choice for electric vehicles. Generally speaking, based on the consideration of safety cycle, ternary batteries mainly use 3 3 3 3, and the content of 4425 320 Ni is relatively low. The higher the PHEV/EV energy density, the more attention will be paid to the ternary material nuclear patent. Three-meter company Argonne Laboratory (ANL) applied for some ternary materials (some of which were contained in lithium-rich manganese-based solid solutions). The practical significance is generally recognized by the industry, which is related to the output of three-meter ternary materials, the South Korean L & Umicore three-meter Industry-University-Research Alliance; Japan (Asia) and Hata Industry (Hata Industry) are major ternary material manufacturers, F DebBASF, and BASF have newly joined ternary upstart four-core manufacturers (S O N Y, Panasonic, Samsung SDI LG), and the ternary material lithium cobaltate electrode materials are all in proportion. Internally, the production capacity of the four factories is equivalent to that of global battery manufacturers, which is an important manifestation of their technological leadership. The main problems and modification methods of ternary materials At present, the main problems of NMC applied to battery energy storage include: (1) Due to the mixed discharge effect of cations and ions and the change of the first charging range of material surface microstructure, the first charging and discharging efficiency of NMC is generally 90%; (2) Ternary material battery is more serious in gas production and safety, and the high-temperature storage period needs to be improved; (3) The low conductivity lithium ion diffusion coefficient makes the rate performance of the material ideal; (IV) Ternary material particles aggregate into two spherical particles. The compaction of ternary material electrode is limited due to the high pressure crushing of two kinds of particles, which limits the improvement of energy density of battery cells. At present, the modification measures widely used in the industry include: impurity doping to improve the related surface properties (thermal stability, cycle performance or rate performance, etc.). ) materials. The electrochemical performance of a surface or part can often be improved by doping modification of materials, and it is accompanied by the specific capacity of materials. Reducing NMC according to the same doping elements: cation doping, anion doping and compound doping cation doping, the actual effect is limited to Mg, al, Ti, Zr, Cr, Y, Zn. NMC is suitable for cation doping to inhibit the cation mixing of Li+ Ni, which is helpful to reduce the cation doping of primary and secondary capacity, make the layered structure more complete, improve the NMC rate, improve the stability of crystal structure and improve the cycle performance of materials. The thermal stability effect is more obvious. Anion doping is mainly F doping, which is similar to the radius of oxygen source. Proper F doping promotes the sintering of materials and makes the structure of polar materials more stable. F doping can stabilize the interface between substance and electrolyte and improve the cycling performance of polar materials. Like mixed doping, NMC is used to dope F or several cations. When the widely used Mg-F, Al-F, Ti-F, Mg-Al-F and Mg-Ti-F are mixed and doped with NMC, the cycle rate performance is obviously improved and the thermal stability of the material will be improved. At present, the doping modification of NMC by mainstream manufacturers depends on doping elements, and the doping amount is small, which requires manufacturers to have certain R&D strength. NMC impurity doped two precursors. The wet doping in the precipitation stage and the dry doping in the sintering stage are all wrong. Manufacturers need to choose the appropriate technology route according to the economic situation of their own technology accumulation. The so-called all roads lead to Rome and suit your own route. The surface coating of NMC is oxide. The two oxides include magnesia, alumina and zirconia. The main non-oxides are AlPO IV, AlF III and LiAlO II. The surface coating of LiTiO secondary machine is mainly to reduce the mechanical side reaction between materials and electrolyte, inhibit metal dissociation and optimize the cycle performance of materials. The coating on the same machine reduces the repeated charging and discharging process of the material, and the collapse cycle performance is favorable. The surface coating of NMC reduces the residual alkali content on the surface of high nickel ternary materials. The author talks about the difficulties of surface coating. Firstly, the selection and use of coatings and the small amount of coatings are all problems of coating with dry coating precursors. For wet coating, manufacturers need to choose the appropriate process route according to their own conditions, optimize and improve the production process, mainly to improve the quality of NMC products, reduce the residual alkali content on the surface, improve the integrity of crystal structure, and reduce the fine powder content of materials. This has a great influence on the electrochemical properties of Sudu materials. Adjusting the Li/M ratio, improving the rate performance of NMC and increasing the thermal stability of materials require manufacturers to understand the crystal structure of ternary materials. Compared with other polar materials, the precursor of ternary materials produces NMC by its unique precursor precipitation production process. Although the precursors of LCO and LMOLFP are usually produced in liquid phase, and the high-end materials are produced in solid phase, ternary materials (including NCAOLO) are still the mainstream processes of several materials. Only by using liquid phase can the original level of elements be mixed evenly, and the solid phase is unique. The precipitation process makes NMC modify several polar materials more easily and effectively. At present, the mainstream NMC precursor production adopts hydroxide precipitation method, NaOH as precipitant and ammonia complexing agent to produce high-density spherical hydroxide precursor. The advantage of this method is that it is easier to control the particle size, specific surface area and morphology tap density of the precursor. It is easier to treat wastewater (containing NH trisodium sulfate) in actual production reactor operation, which may increase the total output of carbonate. From the control point of view, the precipitation process has some advantages. Even if a complexing agent is used, the main problems in the process of producing spherical granular carbonate are poor process stability and easy control of carbonate precursor impurities (NaS) in product granularity. The high content of phase hydroxide precursor affects the electrochemical properties of ternary materials, and the tap density of carbonate precursor is lower than that of hydroxide precursor, which limits the energy density of NMC. From the author's cost control and practical application of ternary battery with high specific surface area, carbonate technology is considered as the mainstream hydroxide. At present, domestic polar material manufacturers generally ignore the production of ternary material precursors and R&D departments, and manufacturers directly buy precursors for sintering. The author should emphasize the precursor quality (morphology, particle size, particle size distribution, specific surface area, impurity content, tap density, etc.). This is very important for the precursor of ternary material production. It is said that the precursor technology content of ternary materials is 0%, and the sintering technology is basically transparent. Judging from the quality control of this product, ternary manufacturers must produce their own precursors. The actual mainstream manufacturers of ternary materials are Umicore, Nichia and L & ampf. Except Dongda Industry, only the self-produced precursors have enough production capacity to be suitable for outsourcing. Internal electrode manufacturers must develop precursors and attach great importance to the control of residual alkali content on ternary and ternary materials (including NCA). The content of residual alkali on the surface is high, and its practical application is quite outstanding. The basic substance on the surface of NMC is mainly the storage substance in the form of Li-SO-4 LiOH outside Li-CO-3. The basic compounds on the surface mainly exist in the actual production process of lithium salt at high temperature. Volatile components in the Li/M ratio (that is, the right amount of lithium salt) increased slightly to make up for the loss in the sintering process, and a small amount of Li remained (in the form of Li-O at high temperature). When the temperature decreases at room temperature, Li Er O adsorbs air, and CO Er O LiOHLi Er CO, three types and two types of experiments have proved that oxygen negative ions on the surface of polar substances leave the air, and carbonate reacts with lithium to migrate from the surface, forming Li Er CO on the surface of the material, and the three-way partner distorts the surface oxide layer, which has a deoxidized structure on the surface of the material. Any polar material will encounter the problem of less carbonate exposed to the air. The types of polar materials are as regular as the difficulty of surface shape. NCA ≈ high nickel NMC > low nickel NMC≈LCO > LMO>；; LFP said that the residual alkali content on the surface of ternary or binary materials is directly related to the Ni content. The negative effect of high residual alkali content on the surface of polar materials is firstly to affect the electrochemical properties of NCA nickel-rich ternary materials, which are easy to freeze during homogenization. The content of basic oxides on the main surface is too high, which leads to the increase of electrochemical performance of basic compounds on the surface, the reverse capacity loss and the deterioration of cycle performance. In addition to NCA nickel-rich ternary materials, it is said that lithium, cobalt and three high voltages on the surface can solve the problem of battery flatulence. In the practical application of ternary material batteries, it is of great significance to reduce the residual alkali content on the surface of the primary tape with potential safety hazards. At present, domestic manufacturers generally use ternary materials for water washing and low-temperature secondary sintering (water washing+secondary sintering) to reduce the residual alkali content on NMC surface, and the surface residual alkali cleaning is more thorough. Its shortcomings are not obvious. The rate cycle performance of ternary materials is obviously reduced, and the use requirements of Dudley battery are increased by washing and secondary firing. The author also suggests a series of measures to effectively reduce the surface alkali content of ternary materials. In the precursor stage, the ammonia content should be controlled to protect the atmosphere from the influence of high nickel ternary materials, and even appropriate additives should be added to reduce the carbon and sulfur content. Li+ should be strictly controlled in the mixing stage. The sintering temperature is optimized in the M ratio sintering stage, and the oxygen pressure is controlled in the annealing stage, and the cooling rate is controlled in the workshop humidity vacuum sealing packaging materials. The comprehensive application effect of a series of technical measures can reduce the residual alkali content on the surface of ternary materials. Even if the surface pH value of unmodified high nickel is controlled, in addition, surface coating can reduce the residual alkali content on the surface of ternary materials, which is effective in nickel NMC. I want to emphasize that the problem of residual alkali on the surface of polar materials, especially NMCNCA, must attract the attention of polar materials factories. Scientists attach great importance to the fact that the content of NCA direct energy mass production technology must be as low as possible or controlled within a stable and reasonable range (generally 500- 000 ppm), and the temperature and humidity of the atmosphere must be strictly controlled to realize closed production. HEVPHEV power battery adopts NMC cloth with high specific surface area and narrow particle size, which should take into account the requirements of power and energy density. The requirements of mechanical ternary materials should meet the requirements of high rate as ordinary ternary materials used in consumer electronics, and the specific surface area of ternary materials should be increased, which is contrary to the requirements of ordinary ternary materials. The specific surface area of ternary materials is determined by the precursor BET. How to keep the sphericity of the precursor, set the vibration density and improve the BET of the precursor as much as possible? Mechanical ternary materials need to overcome technology. Improving precursor BET is a difficult problem. It is necessary to adjust the concentration of complexing agent and change some reactor parameters, such as speed, temperature and flow rate. Some process parameters need more comprehensive optimization, which can sacrifice the sphericity of the precursor, and the tap density will affect the energy density of the battery. The way to improve the BET effect of precursor by carbonate precipitation method is that there are some technical problems in the above carbonate method. I believe that the carbonate precipitation process may produce ternary materials with high specific surface area. In the process of in-depth study of value, the basic requirement of battery cycle life is to match at least half of the vehicle life at present (bar-according to 0). According to the 00%DOD cycle, it will reach 5000. At present, the cycle life of ternary materials can reach the target. At present, what is reported internationally is the cyclic record of ternary materials. The cycle life of NMC5 ternary battery made by Samsung SDI is close to 3000. The author thinks that the cycle life of ternary materials can be improved besides the original doping. Surface coating is an important method to control the particle size distribution of products. The battery point is particularly important. I know that ternary materials have a wide particle size distribution. Second, the metal content of wide-particle size particles is separated from fine elements, which shows that the lithium-nickel content of particles is higher than the average (lithium-nickel content) and the lithium-nickel content of particles is lower than the average (lithium-nickel foot). During the charging process, the total lithium removal structure of polarized primary particles is destroyed, and the side reaction between charged high nickel particles and electrolyte is more intense, and the high temperature is more obvious, resulting in faster particle cycle life and particle attenuation. On the contrary, the overall cycle performance of materials is actually determined by particles, which is an important factor restricting the cycle progress and improvement of ternary materials. The C-3 battery embodies the cycle requirement of 500, and the cycle life of the battery is required to reach 5000, which improves the cycle performance of ternary materials. It is necessary to produce ternary materials with uniform particle size (particle size distribution is 0. Bar) to avoid the challenge of storing particles in industrial production belt as much as possible. The particle size distribution of NMC depends entirely on the precursor. I will see that the ternary materials produced by precursors are of great significance to hydroxides. The precipitation process uses an ordinary reactor to produce a particle size distribution of 0. 0. It needs to use specially designed reactors or technological progress at the physical level to reduce the particle size distribution of precursors. The particle size distribution of the precursor particles is 0. In fact, the decrease in the yield of particulate precursors is higher than the increase in the yield of precursors. The comprehensive utilization of raw materials reduced the output. Manufacturers must establish production lines for precursor collection and reprocessing, and they need to comprehensively weigh the advantages and disadvantages and choose the appropriate process. In fact, the ternary material of narrow particle size cloth should obviously improve the coating performance of the pole piece, which not only increases the cycle life of the battery, but also reduces the polarization of the battery and improves the rate performance. Due to the limitation of technical level, ternary manufacturers have not realized the importance of the problem at present. The author thinks that the important technical indexes of narrow particle size cloth ternary materials hope that this problem can attract the attention of domestic manufacturers. The safety problem of ternary material is more prominent than that of LFPLMO battery, which mainly shows that the needle filling condition is easy to be closed and the battery flattens more seriously. The author thinks that the safety of ternary battery needs to be done on both sides with the electrolyte of the material itself, in order to achieve the ideal effect. NMC material itself must first strictly control the residual alkali content on the surface of ternary materials. Except for the measures discussed by the author, the surface coating is ineffective. Generally speaking, the effect of alumina coating is obvious. In recent years, ALD technology has been developed to improve the electrochemical performance of NMC by coating several layers of al2o 3 unevenly. Obviously, how to reduce the cost of ALD coatings of 50 million yuan per ton is still the premise of practical application of ALD technology. It is necessary to improve the structural stability of NMC mainly by using impurity doping. At present, the composite doping of anion and cation is beneficial to improve the thermal stability of the material structure. In addition, the Ni content must be considered. In NMC, its specific capacity increases with the increase of Ni content. I wonder if the negative effect caused by increasing the nickel content is the same as that of Li Ni layer. Obviously, it directly deteriorates the cycle rate performance, increases the nickel content, and makes the stability of the crystal structure worse. With the increase of some elements, the residual alkali content on the surface leads to more serious safety problems, especially under high temperature test conditions. The higher the nickel content of ternary materials, the more comprehensive the indexes that must be weighed. The author requires that high nickel ternary materials use energy-limiting paint alone, and then the negative effect of high nickel tape is enough to offset the loss of capacity improvement advantage. In addition, the author wants to point out that the fine powder content of the product should be strictly controlled. The concept of fine powder particles is the same. The shape of fine powder particles is regular, and the particle size is 0.5 micron. It is difficult to produce only regular particles. How to control and eliminate the potential safety hazards left by the use of electrode materials? The safety of ternary battery needs to be combined with the improvement of electrolyte to solve the technical secrets involved in electrolyte block. Generally speaking, the electrochemical performance of ternary DMC system should be reduced by adding PC to DEC. Electrolyte salts improve the high temperature cycling performance of ternary materials. Electrolyte modification is the main special functional additive at present. At present, the known additives are VEC, DTA, LiDFOB, PS, etc. It is to improve the electrochemical performance of ternary batteries, which requires the joint research of battery manufacturers and electrolyte manufacturers. It is suitable for the application of ternary materials in ternary materials market. It is generally expected that lithium cobaltate will replace dozens of lithium cobaltate batteries made of fast ternary materials, and the status of the batteries will not be weakened. The sales of lithium cobaltate will still occupy more than 50% of the global market share. In my opinion, it is difficult for ternary materials to replace lithium cobaltate in the field of triple C in a few days, and it is also difficult to meet the rigid requirements of smart phone voltage platform by using ternary materials alone. On the other hand, the ternary material two-particle structure is difficult to make high voltage, which makes the bulk energy density of ternary material battery still reach high-end (high voltage and really high voltage), and ternary materials in lithium cobaltate field are still playing an auxiliary role. Single crystal high-voltage ternary materials and high-voltage electrolyte maturation can be more widely used in the field of ternary materials. Refer to the author's previous discussion on the development of the pole piece material industry of consumer-grade lithium-ion batteries. In fact, the author tends to think that ternary materials are more suitable for power tools and batteries. Recently, the energy density requirements of two electric vehicles for power batteries have been significantly improved, and automobile manufacturers began to test ternary batteries only by energy density. It is said that HEV requires low energy density, LMO and LFPNMC batteries meet the requirements, and PHEV requires high energy density. At present, NMC/ NCA battery meets the requirements of PHEV, which is influenced by the technical route of Tesla battery. The application trend of NMC must be expanded. At present, South Korea has focused on the research and development of LMO batteries, and the trend of transferring NMC batteries is not obvious. The Ministry of Industry and Information Technology gives new energy automobile battery enterprises three hard indicators: 20 press 5, and the energy density of single battery is 0Wh/kg (module energy density is 50 Wh/kg). At present, NMC batteries meet the first three hard indexes according to the cycle life of 0/ Wh of more than 2000 times or the calendar life of less than 2 yuan. The author thinks that LFPLMO, as the mainstream material of NMC battery, can retreat to a supporting role because of its own shortcomings. At present, the industry comparison shows the trend of NMC batteries, and the supply and demand of high-end ternary lithium batteries will show in the next three to five years. In the short term, at present, the internal force lithium battery is still the main lithium manganate-assisted internal lithium battery electric vehicle enterprise of lithium iron phosphate, and lithium iron phosphate has mastered the technology of two or three internal forming mature batteries to improve the technical level, and then crossed the technical route of ternary materials. It is more urgent for material battery manufacturers to step up the layout of ternary materials. The author is talking about ternary materials. LMOLFP is relatively high in NMC stage, and the original intention of LFP has been strongly supported. At present, the intrinsic quality is high, and the ternary material price is as high as 5- 10000 yuan/ton, and the high-end LMO is around 10000 yuan. At present, the quality is about 1 10,000 yuan lower than that of LFP, and the space of LMOLFP is 60,000 yuan higher and lower than that of LMO. LFP landing-80,000 yuan can limit the scale of ternary materials used in key components of batteries. Let me briefly analyze the ratio of ternary material to surface metal. It is found that the production process of single raw material can narrow this space. In fact, the author thinks that there are two more realistic ways to improve the quality of NMC products and achieve super-cycle life. Compared with the cost of a single cycle, increasing the cycle life may reduce the overall usage of the battery during the whole life. This requires enterprises to have strong R&D technical strength, which increases the production cost, although polar materials are very popular in the world. At present, it is difficult to establish a complete battery collection system to charge and utilize metal resources in another way, similar to the compulsory collection of waste lithium batteries by Xijiatong Jiali. The author simply calculated that after deducting the collection cost (CoNiMnFe is too cheap to be confiscated), metal recycling accounts for almost 20%- 30% of raw materials. Finally, the cost of ternary materials is reduced by about 0%-20%. Considering the competitiveness of ternary batteries with higher energy density than Wh compared with LFPLMO batteries, it is necessary for the two leading domestic enterprises to integrate the industrial chains of metal and mineral raw materials, ternary materials production and battery collection, realize the optimal allocation of resources and reduce production costs. The author thinks that the R&D technical strength of domestic manufacturers is generally weak, the resource utilization ratio (cost) and the product quality are relatively balanced and the market is rapidly expanding.