CATL revealed at the annual general meeting that CATL will release sodium batteries around July this year. Once the news was released, it caused heated discussions on the Internet. On the one hand, the Ningde era has always had a pivotal position in the battery field. Now many electric vehicles on the market are equipped with Ningde era batteries; on the other hand, they are the same as lithium-ion batteries. In contrast, sodium ion batteries are more suitable as large-scale energy storage devices.

Sodium-ion battery is a kind of secondary battery (rechargeable battery), which mainly relies on the movement of sodium ions between the positive and negative electrodes to work, similar to the working principle of lithium-ion batteries. During charging and discharging, Na+ intercalates and deintercalates back and forth between the two electrodes: during charging, Na+ deintercalates from the positive electrode and inserts into the negative electrode through the electrolyte; the opposite is true during discharge.

Since John BGoodenough invented the lithium battery 40 years ago, the lithium battery has become more and more important, and it has become the standard equipment for smart phones and electric cars. Many star companies related to lithium have also emerged in China, such as the Ningde era of lithium batteries, and Ganfeng Lithium, which provides lithium mineral resources.

However, lithium resources are very scarce on the earth. In the future, lithium resources are also facing the same danger of exhaustion as oil resources.

Moreover, the process for extracting lithium is also relatively complicated. Extracting lithium from the salt lake requires technologies such as extraction or electrodialysis membrane separation, which is cumbersome and costly.

From the emergence of lithium cobalt oxide battery technology in 1980, to the emergence of lithium manganese oxide technology in 1982, to the introduction of the first commercial lithium battery by Sony in 1991, and the introduction of lithium iron phosphate technology in 1997, there were no new lithium batteries for the next 20 years. With the advent of technology, lithium batteries themselves have begun to face the limits of growth, especially as it is becoming more and more difficult to increase their service life and energy density, so there is a natural demand for finding new alternative technologies.

Are there alternative products for lithium batteries?

Maybe it is, that is, sodium ion batteries.

Why is it possible for sodium ion batteries to replace lithium batteries?

Sodium is the second lightest metal element on the earth after lithium. From the periodic table, sodium and lithium belong to the same group of elements, and their chemical properties are similar. So in theory, sodium can also be used as lithium. battery. Of course, the atomic radius of sodium is much larger than that of lithium, because sodium atoms have 8 more electrons than lithium atoms, so they naturally grow fat. Once you gain weight, there will be a lot of troubles. For example, it cannot be embedded in graphite like lithium, and it is much heavier than lithium, so that the energy storage per unit mass of the battery is less than that of lithium.

However, sodium has an advantage-the content of sodium on the earth is very high, and its content on the earth is thousands of times that of lithium. There is a lot of sodium in the salt we eat, and there is also a lot of sodium in the sea water. Because of its rich content, sodium is much cheaper than lithium. In the market, the price of lithium carbonate as a lithium raw material costs tens of thousands of yuan per ton; and the price of sodium chloride as a sodium raw material is only a few thousand yuan per ton. Therefore, as a battery, a prominent advantage of sodium batteries compared with lithium batteries is that they are cheap, which is a very core advantage for industrialization. Because the industry is most concerned about cost.

Of course, cost advantage does not mean technical advantage. The key depends on whether sodium can really be used as a battery. The positive electrode material, negative electrode material, and electrolyte of the battery are the three basic components, none of which poses fundamental difficulties for sodium batteries. So sodium batteries can exist. Taking the negative electrode material of sodium ion battery as an example, there are many kinds of materials that can be used as negative electrode, and the most researched is mainly hard carbon materials. Although the sodium storage mechanism of hard carbon has not been finalized, and the performance of the negative electrode of the battery made by different people is quite different, this is only a process problem, and one day it will be standardized.

In fact, the working principle of sodium-ion batteries is not much different from that of lithium-ion batteries. It uses the process of inserting and removing sodium ions between the positive and negative electrodes to achieve charge and discharge. When charging, sodium ions are extracted from the positive electrode and inserted into the negative electrode through the electrolyte, and at the same time, the electronic compensation charge is supplied to the negative electrode through an external circuit to ensure the balance of the positive and negative electrodes. When discharging, the opposite is true. Sodium ions are extracted from the negative electrode and inserted into the positive electrode through the electrolyte. Under normal charging and discharging conditions, the insertion and extraction of sodium ions between the positive and negative electrodes should not destroy the basic chemical structure of the electrode material (of course, it may produce a certain memory effect under actual conditions, and may also cause the aging of the electrode material).

So, do sodium ion batteries have technical advantages? Some people claim that in principle, the charging time of sodium-ion batteries can be shortened to 1/5 of that of lithium-ion batteries-although the current public data in this area is not very sufficient, so they can only say that this is a potential advantage. There are also related materials claiming that the life of sodium-ion batteries is more than 10 years, while the life of lithium-ion batteries is usually only 3-4 years. However, this is doubtful. According to the research of Silicon Valley Power, the main problem of sodium-ion batteries is cycle life. Not high, so this is a controversial point.

First low-speed electric car with sodium-ion battery has come out

The current conclusion is that sodium-ion batteries have the advantage of low cost, while other technical advantages are not obvious. So what is the current research and development situation in this field?

At present, the energy density of sodium ion batteries can only reach 120 Wh/kg. Therefore, in the technical index of energy density, sodium ion batteries cannot be compared with lithium ion batteries, because the energy density of lithium batteries is more than 300 watt-hours/kg.

From the perspective of energy density, current sodium ion batteries can only reach less than half of lithium batteries, so sodium ion batteries can only be used in low-speed electric vehicles, electric boats, home energy storage and other fields that require lower energy density. At present, it is not possible to use sodium batteries to make high-speed electric vehicles. It is more appropriate to use sodium batteries for electric bicycles. For example, the sodium-ion battery pack developed by a subsidiary of China Great Wall has realized demonstration applications on electric bicycles.

Sodium battery is an emerging industry, it may need more research and development to bloom the rose of time. The industrialization of sodium batteries is accelerating.

In addition to the efforts of the business community, there are also many research teams in the academic community working on the research and development of sodium batteries. For example, Professor Xia Hui of Nanjing University of Science and Technology has made progress in the research of manganese-based cathode materials for sodium batteries, and related results have been published in Nature Communications. Professor Xia Hui’s research team found that the specific capacity of the sodium battery electrode made of this positive electrode material reached 211.9 mAh/g, while the specific capacity of the current lithium battery cathode material on the market is about 140 mAh/g. However, in the opinion of the Silicon Valley Powermaster, the research on sodium ion batteries by the college is mainly to make permutations and combinations of various water-based electrolytes, organic electrolytes and solid electrolytes, as well as corresponding different positive and negative materials. These permutations and combinations can always be compared. High specific capacity, but for the industry, the core issue is not the specific capacity issue. The core issue is the cycle life of the battery—that is, how long the battery can be used and how many times it can be charged and discharged. It is what the industry is most concerned about.

Therefore, from the perspective of the industrial situation, the current industrialization of sodium batteries is still in its infancy, and many research results are only circulated in universities and research institutes. It will take some time before they are actually implemented. Some researchers even say that on the earth Before the lithium reserves are used up, sodium-ion batteries have no chance at all. However, in the opinion of Silicon Valley Powermaster, sodium batteries may also be like artificial intelligence technology. At the beginning, they may not be optimistic and can only be circulated in the academic school, but perhaps one day there will be a sudden change and quickly land in the industry. This is very possible, so sodium batteries are actually worthy of great attention from forward-thinking entrepreneurs and investors.

Sodium ion batteries are one of the important development directions of energy storage batteries in the future. With the continuous advancement of sodium-ion R&D technology, the commercialization process of sodium-ion batteries will continue to accelerate, and perhaps the advance layout of this field is expected to take the lead in the field of new energy batteries. Of course, it seems too early to say that sodium-ion batteries replace lithium batteries.

In the future, JUNLEE Energy, which has been committed to battery research and development, is a challenge and an opportunity. The R&D team of engineers will provide the world with more economical new energy batteries, and will improve lithium-ion battery technology to reduce the total cost.

JUNLEE Group is an integrated full power energy factory that specializes in Uninterruptible Power Supply (UPS), Lead-Acid Battery, Battery pack, EV battery, Energy Storage Battery, Energy storage power station, Power pack Gel battery, PV Inverter and Solar system.

Production capacity reach 200000 KVaH per month. Products apply to Electric vehicles,electric mobility, solar & wind energy storage system, UPS, backup power, telecommunication, medical equipment and lighting.

JUNLEE sets up "Power research center" with more High-tech products.More than 100 engineers provided in-time and efficient one-stop solutions.

They mission strives to bring green power to the world.

To learn more about Li-ion batteries, please refer to