Lithium, sodium and potassium belong to group IA alkali metals in the periodic table of elements, which are similar in physical and chemical properties, and can all be used as metal ion carriers for secondary batteries in theory.
Because of its smaller radius than sodium and potassium ions, high standard potential and high specific capacity, lithium was used in secondary batteries earlier and more widely.
However, the global lithium resources are limited. With the development of new energy vehicles, the demand for batteries has risen sharply, and the bottleneck at the resource end has gradually emerged. The periodic fluctuation of lithium supply and demand caused by this has a negative impact on the operation of battery enterprises and OEMs. Therefore, the research and mass production process of battery system with more abundant resources and lower cost has been accelerated within the industry. As a substitute for lithium, sodium has emerged and attracted more and more attention in the battery field.
The comprehensive performance of 1.2 is better than that of lead-acid battery, and its energy density is short.
The working principle of sodium ion battery is similar to that of lithium ion battery. Similar to other secondary batteries, sodium ion batteries also follow the working principle of deintercalation. During the charging process, sodium ions are removed from the positive electrode and embedded into the negative electrode. The more sodium ions embedded in the negative electrode, the higher the charging capacity. When discharging, the process is reversed. The more sodium ions returned to the positive electrode, the higher the discharge capacity.
The energy density is weaker than lithium battery and stronger than lead acid.
In terms of energy density, the energy density of sodium ion batteries is 100- 160Wh/kg, which is much higher than that of lead-acid batteries (30-50Wh/kg), and it also overlaps with lithium iron phosphate batteries (120-200Wh/kg).
At present, the energy density of mass-produced ternary batteries is generally above 200Wh/kg, and the high nickel battery even exceeds 250Wh/kg, which has a significant leading edge for sodium batteries.
In terms of cycle life, sodium battery is more than 3000 times, which is also far more than 300 times of lead-acid battery.
Therefore, only from the perspective of energy density and cycle life, sodium batteries are expected to replace lead-acid and lithium iron phosphate batteries in start-stop, low-speed electric vehicles, energy storage and other markets, but it is difficult to be applied to electric vehicles and consumer electronics, and lithium batteries will remain the mainstream choice in these two fields.
High safety and excellent high and low temperature performance.
The internal resistance of sodium ion battery is higher than that of lithium battery, and the instantaneous calorific value is smaller, the temperature rise is lower and the heat dissipation temperature is higher than that of lithium battery, so the safety is higher. Therefore, the sodium battery will not catch fire or explode in the tests of overcharge, overdischarge, short circuit, acupuncture and extrusion.
On the other hand, the sodium ion battery can work normally in the temperature range of -40 ~ 80℃, and the capacity retention rate is close to 90% in the environment of -20℃, and its high and low temperature performance is better than other secondary batteries.
Good rate performance, fast charging has advantages.
Relying on the open 3D structure, sodium ion battery has good rate performance, and can adapt to responsive energy storage and large-scale power supply, which is another advantage of sodium battery in the field of energy storage.
In terms of fast charging ability, the charging time of sodium ion battery is only about 10 minute. Comparatively speaking, for mass-produced ternary lithium batteries, it usually takes 30 minutes to charge the battery from 20% to 80%, and it takes about 45 minutes for lithium ferrous phosphate.
2. 1 resource end: overcoming the bottleneck of lithium battery
Lithium batteries are facing resource bottleneck, and sodium resources are relatively abundant. The abundance of lithium in the crust is only 0.0065%.
According to the report of the US Geological Survey, with the increasing exploration of lithium resources, the global lithium mine reserves will increase to 2 1 10,000 tons of lithium metal equivalent (equivalent to1.1.20 million tons of lithium carbonate) in 2020, with a year-on-year increase of 23.5%. If each electric vehicle uses 50kg lithium carbonate, regardless of other downstream markets of lithium carbonate, the current lithium reserves can only meet the demand of 2 billion vehicles, so there is a bottleneck in the resource side.
From a regional perspective, the lithium reserves of the world's major lithium mine resource countries have increased to varying degrees, among which Australia and China have increased more. Among them, Australian lithium reserves have increased from 2.8 million tons in 20 19 to 4.7 million tons of lithium metal equivalent, while China's lithium reserves will increase by 50% in 2020, reaching10.5 million tons of lithium metal equivalent.
Overall, Chile and Australia are still the top two countries in the world, accounting for 43.8% and 22.4% of the global lithium resources reserves in 2020, respectively.
In contrast, the crustal abundance of sodium resources is 2.74%, which is 440 times that of lithium resources. At the same time, it is widely distributed and simple to extract, and sodium ion batteries have strong advantages in resource end.
The rise of lithium price brings disturbance to the cost end of enterprises.
In the short term, with the increase of demand for lithium in 202 1, the supply of lithium ore in the upstream will shrink and be out of stock, and the prices of lithium ore and lithium salt will bottom out in 2020, and the prices will rebound sharply in the first half of 202 1. In the long run, the capacity bottleneck of lithium resources has triggered the market's expectation that the lithium price center will move up.
For enterprises, long-term stable raw material prices are of great significance to their normal operation, and the continuous rise of lithium prices may accelerate the process of enterprises looking for more cost-effective substitutes.
China's lithium resources are highly dependent on foreign countries.
China lithium mines are mainly distributed in Qinghai, Tibet, Xinjiang, Sichuan, Jiangxi, Hunan and other provinces, including spodumene, lepidolite and salt lake brine.
Restricted by objective factors such as lithium extraction technology, geographical environment and traffic conditions, the development of lithium resources in China has been slow for a long time, mainly relying on imports; In recent years, with the downstream demand growth and technological progress, the development progress of lithium resources in China has been accelerated.
Without considering the inventory, the dependence of China lithium industry on external resources will exceed 70% in 2020, and it will remain at a high level.
It is of strategic significance to develop sodium ion batteries.
In addition to reducing carbon emissions and solving environmental problems, the purpose of China's vigorous development of new energy vehicles is to reduce its dependence on traditional fossil fuel imports.
Therefore, if the resource bottleneck problem cannot be effectively solved, the significance of developing electric vehicles will be discounted.
In addition to lithium resources, other links of lithium batteries, such as cobalt and nickel, are also facing import dependence and price fluctuation, so the development of sodium ion batteries is of strategic significance at the national level.
In 2020, the U.S. Department of Energy clearly took sodium ion batteries as the development system of energy storage batteries; The "Battery 2030" project of the European Union's energy storage plan ranks sodium ion batteries at the top of non-lithium ion battery systems, and the European Union's "Horizon 2020 Research and Innovation Plan" regards sodium ion materials as the key development project for manufacturing durable batteries for non-automotive applications. The Guiding Opinions on Accelerating the Development of New Energy Storage issued by two ministries and commissions in China proposed that energy storage technologies should be diversified, and large-scale experiments and demonstrations of flywheel energy storage, sodium ion batteries and other technologies should be accelerated.
Sodium ion batteries have attracted the attention and support of more and more countries.
2.2 material end: highlighting the cost advantage
Cathode material
The positive electrode material is sodium ion active material, with various choices.
Cathode material is the key factor to determine the energy density of sodium ion battery. At present, the potential materials for mass production are transition metal oxide system, polyanion (phosphate or sulfate) system and Prussian blue (ferricyanide) system.
Transition metal oxides are the mainstream choice of cathode materials at present.
Layered transition metal oxide 2(M is a transition metal element) has a high specific capacity, and has many similarities with lithium battery cathode materials in synthesis and battery manufacturing. It is one of the mainstream materials with potential for commercial production of sodium ion battery cathode materials.
However, layered transition metal oxides are prone to structural phase transition during charging and discharging, and their capacity decays seriously during long-cycle and high-current charging and discharging, resulting in low reversible capacity and poor cycle life.
Common improvement methods mainly include bulk doping and surface coating of cathode materials.
The use of P2-type copper-based oxide (P2-Na0.9Cu0.22Fe0.3Mn0.48O2) in Zhongkehai sodium significantly improved the capacity level of cathode materials, and the battery energy density reached 145Wh/kg.
O3-NaFe0.33Ni0.33Mn0.33O2 used in sodium innovative energy has high gram capacity (over 130mAh/g) and good cycle stability.
Faradion Company in Britain adopts nickel-based oxide materials, and the energy density of the battery exceeds 140Wh/kg.
Sodium vanadate phosphate is one of the main research directions.
Polyanionic compound Na[()] (M is a metal ion with variable equivalence of Fe and V, and X is an element such as P and S) has the advantages of high voltage, high theoretical specific capacity and stable structure, but the low electronic conductivity limits the specific capacity and rate performance of the battery.
At present, the most studied materials in industry are mainly sodium ferric phosphate, sodium vanadium phosphate and sodium ferric sulfate. And the conductivity and capacity are improved by carbon coating and adding fluorine.
Sodium Innovation Energy takes sodium vanadate phosphate as one of the key research and development cathode materials for sodium batteries, and Dalian Institute of Physics and Chemistry of Chinese Academy of Sciences has realized the efficient synthesis and application of sodium vanadate trifluoride.
Prussian blue material has higher theoretical capacity.
Prussian blue material, Na[()6] (Fe, Mn, Ni and other elements) has an open frame structure, which is beneficial to the rapid migration of sodium ions; Theoretically, two-electron reaction can be realized, so the theoretical capacity is high.
However, there are also some problems in the preparation process, such as difficult control of structural water content, easy phase change and side reaction with electrolyte, resulting in poor cycle performance.
Liaoning NaCI is committed to the industrialization research of Na 1.92FeFe(CN)6, and its theoretical capacity is as high as170 mAh/g; Contemporary Anpu Technology Co., Ltd. uses Prussian white (Nan[Fe()6]) material, and innovatively rearranges the charge of the bulk structure of the material, thus solving the core problem that the capacity of Prussian white rapidly decays during the cycle.
Sodium ion batteries have significant cost advantages at the material end.
Because the price of sodium carbonate is much lower than that of lithium carbonate, and the cathode material of sodium ion battery usually adopts bulk metal materials such as copper and iron, the cost of cathode material is lower than that of lithium battery.
According to official website data of Zhongke Haina, the anode material cost of sodium battery with NaCuFeMnO/ soft carbon system is only 40% of that of lithium battery with lithium ferrous phosphate/graphite system, and the total material cost of the battery is 30%-40% lower than that of the latter.
Negative electrode material
The negative electrode materials of sodium ion batteries mainly include carbon-based materials (hard carbon and soft carbon) and alloys (tin, antimony, etc.). ), transition metal oxides (titanium-based materials) and phosphate materials.
The radius of sodium ion is larger than that of lithium ion, so it is difficult to embed graphite material, so the traditional graphite negative electrode of lithium battery is not suitable for sodium battery.
Alloys generally have large volume changes and poor cycle performance, while metal oxides and phosphates generally have low capacities. Amorphous carbon is the mainstream material of sodium battery.
Among the reported anode materials for sodium ion batteries, amorphous carbon materials have become the most promising anode materials for sodium ion batteries because of its relatively low sodium storage potential, high sodium storage capacity and good cycle stability.
Precursors of amorphous carbon materials can be divided into soft carbon and hard carbon precursors. The former is cheap, can be completely graphitized at high temperature and has excellent conductivity. The latter is expensive (654.38+0-200,000 yuan/ton) and can not be completely graphitized at high temperature, but the specific capacity of sodium storage and the first week efficiency of carbon materials obtained after carbonization are relatively high.
Coal-based materials such as sub-bituminous coal, bituminous coal and anthracite are rich in resources, low in price and high in carbon yield. The negative electrode material of sodium ion battery prepared from coal-based precursor has a sodium storage capacity of about 220mAh/g and a first-cycle efficiency of 80%, which is the most cost-effective carbon-based negative electrode material for sodium ion battery at present. However, this kind of material has the characteristics of micro powder, low tap density and irregular shape, which is not conducive to the processing in the battery production process.
Zhongke Haina takes sub-bituminous coal, lignite, bituminous coal, anthracite and other coal-based materials as the main raw materials, and soft carbon precursors such as asphalt, petroleum coke and needle coke as the auxiliary raw materials, and puts forward a method that can improve the processability and electrochemical performance of coal-based sodium ion battery cathode materials. The preparation process is simple and the cost is low, and the battery cathode material with low micropowder content and high tap density can be obtained.
Contemporary Amperex Technology Co., Ltd. has developed a hard carbon material with unique pore structure, which has the characteristics of easy deintercalation and excellent circulation. The specific capacity is as high as 350mAh/g, which is equivalent to the level of power graphite.
The electrode current collectors are all aluminum foil, so the cost is low.
In graphite-based lithium-ion batteries, lithium can react with aluminum to form an alloy, so aluminum can not be used as the current collector of the negative electrode, and copper can only be used instead.
The anode and cathode current collectors of sodium ion battery are all aluminum foil, so the price is lower; According to official website data of Zhongke Haina, the current collector (aluminum-aluminum) cost of sodium battery with NaCuFeMnO/ soft carbon system is only 20%-30% of the current collector (aluminum-copper) cost of lithium battery with lithium ferrous phosphate/graphite system.
The current collector is the link with the biggest difference between the material cost and the lithium battery except the positive electrode.
shower gel
Similar to lithium-ion batteries, electrolytes in sodium-ion batteries are mainly divided into three categories: liquid electrolytes, solid-liquid composite electrolytes and solid electrolytes.
Generally speaking, the ionic conductivity of liquid electrolyte is higher than that of solid electrolyte.
At the solvent level, ester electrolyte and ether electrolyte are the two most commonly used organic electrolytes, among which ester electrolyte is the main choice for lithium ion battery system, because it can effectively passivate the surface of graphite anode, and its high-pressure stability is better than ether electrolyte.
For sodium ion batteries:
First of all, the mainstream R&D institutions still use ester solvents, such as PC, EC, DMC, EMC and so on. , the positive and negative poles are different, the functional formula is different, and the consumption of PC is higher than that of lithium battery;
Secondly, sodium ions in ether electrolyte and ether solvent molecules can undergo highly reversible intercalation reaction, and a stable electrode/electrolyte interface can be effectively constructed on the surface of anode materials, so it has attracted more and more attention and research.
Finally, water-based electrolyte is also one of the new research fields. Using water instead of traditional organic solvent as electrolyte solvent is more environmentally friendly, safe and low-cost.
On the electrolyte level, lithium salt will be replaced by sodium salt, such as sodium perchlorate (NaClO4) and sodium hexafluorophosphate (NaPF6).
At the additive level, the traditional general additive system has not changed significantly. For example, FEC is still widely used in sodium ion batteries.
other
In terms of diaphragm, sodium ion battery and lithium battery are similar in technology, and there may be some differences in porosity requirements.
In terms of shape packaging, sodium ion batteries also include three routes: cylindrical, soft bag and square.
According to official website, Zhongke Haina mainly adopts cylindrical and soft package routes, and sodium innovation can have three technical routes.
In terms of equipment and technology, it is not much different from lithium batteries, which is conducive to the rapid commercial production of sodium batteries by using ready-made equipment and technology.
The cost after mass production is expected to be lower than 0.3 yuan /Wh.
At present, due to the lack of supporting industrial chain and scale effect, the actual production cost of sodium ion batteries is above 1 yuan/; Policy support and the promotion of leading enterprises are expected to accelerate the industrialization process. If the current market volume of lithium batteries is reached, the cost is expected to drop to 0.2-0.3 yuan /Wh, which is superior to lithium batteries.
3. 1 sodium ion battery returned to the stage to study heat generation.
The research of sodium ion battery began around 1970. At first, sodium ion batteries and lithium ion batteries were the key research directions of scientists in the battery field.
In 1980s, the research of lithium ion cathode materials made a breakthrough at first. With lithium cobalt oxide as the representative and graphite as the cathode material, the lithium battery has achieved excellent performance. What really distinguishes the two is Sony's successful commercial lithium battery in 199 1, and its first application in the field of consumer electronics.
The smooth commercialization of lithium batteries has negatively inhibited the development of sodium ion battery technology. At that time, the cycle life of commercial lithium-ion batteries can reach about 10 times of that of sodium-ion batteries, and their performance is far from each other. Lithium-ion batteries have attracted the absolute attention of scientists, capital and industry.
After 20 10 years, the scene of large-scale energy storage market gradually became clear, and the industry worried that lithium resources might face supply bottlenecks in the future, sodium ion batteries re-entered people's field of vision.
In the following ten years, the world's top national laboratories and universities were vigorously developing sodium ion batteries, and some enterprises began to follow suit.
Including Faradion Company, an international representative, Contemporary Amp Technology Co., Ltd., a domestic representative organization, and China Kohane sodium and sodium innovative energy and lithium battery representative enterprises.
Founded on 20 1 1, Faradion, led by Oxford University in England, is the earliest company engaged in the research of sodium ion batteries in the world. /kloc-a battery system was developed in 0/5, which consists of layered metal oxides and hard carbon systems.
Since then, many countries have also set up relevant institutions and companies. For example, the French Academy of Sciences began to develop sodium vanadium phosphate batteries in 15, and Sharp North America Institute developed sodium batteries with long cycle life almost at the same time.
Zhongkehai sodium
Zhongke Haina, founded on 20 17, is the first company in China to focus on the research and development of sodium ion batteries. The company team mainly comes from the Institute of Physical Chemistry of China Academy of Sciences.
At the end of 20 17, Zhongke Haina developed a 48V/ 10Ah sodium ion battery pack for electric bicycles. 2065438+September 2008, the company launched the first low-speed electric vehicle with sodium ion battery;
From 2065438 to March 2009, the 30kW/ 100kWh sodium ion battery energy storage power station independently developed by the company was successfully demonstrated in liyang city, Jiangsu Province. In September 2020, the company realized mass production of sodium ion battery products with a production capacity of 300,000 tablets/month;
In March of 2002 1 year, the company completed a series of financing of1100 million yuan to build a production line of anode and cathode materials for sodium ion batteries with an annual output of 2000 tons; In June, 20021year, the company's first 1MWh sodium ion battery energy storage system in the world was officially put into production in Taiyuan, Shanxi.
In terms of material system, low-cost Na-Cu-Fe-Mn oxide and anthracite-based soft carbon are used as anode and cathode materials respectively. The energy density of the battery is close to 1.50 Wh/kg, and the cycle life is over 4000 times. Products mainly include sodium batteries, anodes, electrolytes and other supporting materials.
Sodium innovative energy
Sodium innovative energy was born in 20 18. Co-founded by Shanghai Electrochemical Energy Device Engineering Technology Research Center, Shanghai Zijian Chemical Technology Co., Ltd. and Zhejiang Pharmaceutical Co., Ltd., the technical team is mainly from Shanghai Jiaotong University.
From April 2065438 to April 2009, the pilot line of cathode materials was completed and operated at full capacity; From June 5438 to October 2020 10, the second-phase production planning base of the company was built; In July, 20021year, the company and Liu Mengjie jointly released the sodium ion battery system for electric two-wheeled vehicles.
In terms of material system, the company has conducted in-depth research on sodium ferrite-based ternary oxides, and the products mainly include sodium batteries, iron-based ternary precursors, ternary materials, sodium electrolytes and so on.
Contemporary anpei technology co., ltd
Contemporary Ampere Technology Co., Ltd. began to develop sodium ion batteries from 20 15, and the R&D team expanded rapidly. In June 2020, the company announced the establishment of 2 1C Innovation Laboratory, focusing on lithium metal batteries, solid-state lithium batteries and sodium ion batteries in the short and medium term.
In July, 20021year, the company launched the first generation of sodium ion battery, which adopted Prussian white/hard carbon system, and the monomer energy density was as high as 160 Wh/kg. Charging at room temperature 15 minutes, the power can reach more than 80%;
At the low temperature of -20℃, the discharge retention rate is above 90%. The system integration efficiency can reach more than 80%, and the thermal stability far exceeds the national standard safety requirements;
The company said that the energy density research and development target of the next generation sodium ion battery is above 200Wh/kg.
In terms of system innovation, the company developed the AB battery system solution, that is, sodium ion battery and lithium ion battery were mixed and integrated into the same battery system according to a certain proportion, and the balance control of different battery systems was carried out through BMS precise algorithm.
The solution of AB battery system not only makes up for the shortage of energy density of sodium ion battery at present, but also gives play to its advantages of high power and good low temperature performance. Based on the innovation of this architecture, more application scenarios can be developed for lithium-sodium battery system. The company has started the corresponding industrialization layout, and plans to form a basic industrial chain in 2023.
3.2 Sword refers to the energy storage and low-speed car market, with a large potential market space.
It is estimated that the potential market space of sodium ion batteries will exceed 200GWh in 2025.
According to the above analysis, sodium ion batteries are expected to take the lead in replacing applications in energy storage, low-speed vehicles and some low-endurance passenger cars with low energy density and strong cost sensitivity.
Regardless of the expansion of application scenarios brought by battery system improvement (such as lithium-sodium mixing), the installed capacity of global energy storage, two-wheeled vehicle and A00 vehicle will be 14/28/4.6 GWh respectively in 2020, and it is estimated that the installed capacity of batteries in three scenarios will be 180/39/3 1 GWh respectively in 2025.
As one of the important technical routes of secondary batteries, sodium ion batteries have gained extensive attention in the market due to their resource and cost advantages under the current situation that upstream resources are in short supply and manufacturing costs are increasingly concerned.
However, due to its low energy density and limited room for improvement, sodium ion batteries play a greater role as substitutes in the new energy segmentation of the industry, and are expected to take the lead in replacing applications in energy storage, low-speed vehicles and some low-endurance passenger cars with low energy density and strong cost sensitivity, with very limited impact on the mid-to high-end passenger car market.
Driven by leading enterprises, the industrialization process of sodium ion batteries is expected to accelerate.
Industry company:
1) traditional battery and battery material enterprises, layout of sodium ion battery related technologies.
Although there are differences in technical routes, the traditional leading lithium battery enterprises have obvious advantages in capital and research and development, are highly sensitive to various technical routes, and have many layouts for sodium ion battery related technologies.
Contemporary Ampere Technology Co., Ltd. and Peng Hui Energy both maintain long-term R&D investment in the field of sodium electricity, and the latter expects mass production of batteries by the end of 2 1 year; Shanshan Co., Ltd., Putailai, Xinzhou State Concern Xinwangda, Bai Rong Science and Technology and Xiangfenghua all have patents or R&D layouts in the field of sodium batteries or materials.
2) Companies that invest in sodium ion battery enterprises.
Huayang shares, the company indirectly holds the equity of Zhongke Haina 1.66%; Zhejiang Pharmaceutical Co., Ltd. holds 40% equity of Sodium Innovation Energy.
3) Opportunities brought by reshaping the industrial chain.
The amount of sodium ion battery will change the technical route of anode and cathode and lithium salt in electrolyte, and new excellent suppliers will stand out.
Huayang shares and Sinochem Haina have both equity relations and business cooperation. Anthracite produced is one of the important raw materials of Haina coal-based anode, and it is a joint venture with the latter to build anode and cathode materials projects; Zhongyan Chemical and Nanfeng Chemical have upstream sodium salt reserves.
1) Risk that the technical progress or cost reduction of sodium ion battery is less than expected:
The industrialization of sodium ion batteries is still in its infancy. If the speed of technological progress or cost increase is slower than expected, it will affect the industrialization process and lead to the loss of its competitive advantage.
2) Risk that the enterprise promotion is not as good as expected:
At present, due to the small scale, lack of supporting industrial chain and high production cost, the large-scale production of sodium batteries cannot be separated from the vigorous promotion of leading enterprises; If the attitude of enterprises softens in the future, it will affect the industrialization process of sodium batteries.
3) Risk that the market development of energy storage and low-speed vehicles is not as expected:
Sodium ion batteries are mainly used in the fields of energy storage and low-speed vehicles. If the downstream market development speed is lower than expected, it will affect the potential market space of sodium batteries.
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Author: Ping An Securities Zhu Dong Pi Xiu Prince Yue
The original name of the report is "In-depth Report on Power Equipment Industry: Giants Waving Flags and Crying for" Sodium "to Enter the Market, and the Technical Route is Facing Differentiation"