As the name implies, sodium ion battery is a battery that uses sodium ion instead of lithium ion for insertion and extraction to realize charge transfer, and its working principle is similar to that of lithium ion battery. Sodium (Na) is a metal element, which belongs to the same family as lithium, so it has similar chemical properties and can be used to make batteries. Different from lithium ion batteries, the cathode material of sodium ion batteries is Prussian white material, and the cathode material is hard carbon material.
Cathode materials of Prussian white and sodium ion batteries sound strange. Before introducing Prussian white, we should first mention its "close relative"-Prussian blue. Prussian blue is essentially a blue chemical coating, which was first invented by a German worker named Diesbach in the 8th century. Prussian white is a compound with higher sodium content generated by a series of chemical changes on the basis of Prussian blue, which is white, so it is named Prussian white.
We should not be bothered by this strange name, as long as we understand that it is a powdered cathode material. The material has a unique three-dimensional network structure, stable structure and high electrochemical reversibility, and can assist charge conduction, so it is suitable for being used as the cathode material of sodium ion batteries.
As for the hard carbon materials used as cathode materials in sodium ion batteries, they mainly refer to some carbon materials that are difficult to graphitize at high temperatures above 2500℃. Our common grapefruit peel, glucose, cellulose, resin carbon (such as phenolic resin, epoxy resin, carbon black (acetylene black) and so on. ) are all hard carbon materials. Compared with the hexagonal fixed structure of graphite, it belongs to amorphous structure. Compared with graphite, the material with the same mass can hold more ions, which can make the battery have higher energy density.
In fact, sodium ion batteries have existed for a long time, which is not a new technology. Related research started earlier and has been applied in practice. On 20 19, Changzhou, Jiangsu Province opened the world's first sodium ion battery energy storage power station. Just because the energy density and lithium-ion batteries are not competitive, there is no large-scale commercial use. Now, the energy density of the first generation sodium ion battery developed by Amperex Technology Co., Ltd. through technological innovation has reached 160Wh/kg, which is equivalent to lithium iron phosphate battery.
1, security advantage
The safety of batteries should be everyone's greatest concern. Due to the different chemical properties, sodium ion batteries have absolute advantages over lithium ion batteries in safety: they can be tested for safety items such as overcharge, overdischarge, acupuncture, extrusion, etc., without fire and explosion. Moreover, the sodium ion battery can be transported at low power, and there is no need to precharge the battery, which improves the transportation safety of the battery.
Lithium-ion batteries use copper foil as the negative bus. At low voltage, copper foil is easy to be oxidized, which leads to battery performance degradation and failure. Therefore, lithium-ion batteries should be pre-charged before transportation. Compared with low-power batteries, transporting high-power batteries is more risky.
Different from lithium-ion batteries, sodium-ion batteries can use aluminum foil with better stability as the negative bus, and there is no need to worry about the battery performance degradation or even failure caused by negative oxidation.
2, charging 15 minutes can fully charge 80% of the electricity.
At the same concentration, the electrolyte of sodium ion battery has better fluidity and higher conductivity than that of lithium ion battery. So it can have better fast charging performance. According to the test of contemporary Amperex Technology Co., Ltd., the battery can be charged to 80% at room temperature 15 minutes. Compared with lithium iron phosphate battery, it has obvious advantages in charging speed.
3, stronger temperature adaptability
"Don't touch new energy vehicles in the north" and "halve the battery life in winter". We often complain that the battery life of new energy vehicles has dropped seriously in winter. There are even car owners who dare not turn on the warm air and drive with thick quilts. The picture shows the discharge capacity of lithium iron phosphate battery at different temperatures. It can be seen that at MINUS 20 degrees Celsius, the capacity is reduced by about 40% compared with that at normal temperature. Lithium iron phosphate battery is greatly affected by temperature. However, sodium ion batteries are different. After testing, it can still maintain more than 90% power at minus 20℃. Compared with lithium iron phosphate battery, sodium ion battery has stronger temperature adaptability and is more suitable for use in northern China.
4. Resource advantages
As we all know, China is a big producer of lithium batteries, and the lithium, cobalt and nickel materials needed for ternary lithium batteries need to be imported in large quantities, so it is difficult to guarantee the safety of resources. The reserves of lithium, cobalt and nickel on the earth are limited, which is not enough to support the lithium battery industry to the TWh era.
Academician Chen Liquan, the "father of lithium batteries" in China, once said: "All the electric energy in the world is stored by lithium-ion batteries, which is far from enough. Sodium ion batteries are the first choice for new batteries. " Sodium resources required by sodium ion batteries are very abundant on the earth, with an abundance of 2.74%, which is more than 400 times that of lithium. And it is widely distributed. After NaCl, the salt we eat every day is sodium chloride. It can be said that there is sodium where there is sea. Because the anode of sodium ion battery does not need rare and precious metals such as cobalt and nickel, the resource security of China will be greatly guaranteed.
5. Cost advantage
The battery cost is mainly the material cost. In recent years, with the rapid growth of demand for lithium batteries in new energy vehicles, energy storage and other fields, lithium resources are becoming scarcer and the price of lithium is becoming more and more expensive. The cheapest lithium carbonate a few years ago was less than 40 thousand yuan a ton, but now it has doubled to 80 thousand to 9. 1 10 thousand tons. Moreover, the anode of sodium ion battery does not need rare and precious metals such as cobalt and nickel, and the hard carbon material used in cathode is cheaper than graphite used in lithium battery. The cost of comprehensive materials is 30-40% lower than that of lithium-ion batteries.
In addition, the working principle and structure of sodium ion battery and lithium ion battery are similar, and the production line for producing lithium battery can produce sodium ion battery with only a little modification. For Contemporary Amp Technology Co., Ltd., this change is easy to realize, and the existing production line can be used to reduce the input cost and time cost.
Compared with lithium iron phosphate battery, sodium ion battery has the advantages of safety, charging rate, temperature adaptability and cost. The cycle life of the battery is equivalent to that of lithium iron phosphate battery, and the energy density is not as good as that of lithium iron phosphate for the time being. So what will sodium ion batteries be used for? Let's take a look at its application fields.
1, energy storage power station
Because of the low energy density requirement, sodium ion battery has the advantage of being most suitable for manufacturing energy storage power stations. Safety, fast charging speed, good temperature adaptability, low cost and long cycle life are the most needed for energy storage power stations. It is believed that sodium ion batteries will have great applications in the field of energy storage in the future.
2. New energy vehicles for urban transportation
Small urban new energy vehicles, similar to energy storage power stations and Wuling Hong Guang MINI EV, have low requirements on energy density and are also good application scenarios. This kind of electric vehicle does not require high endurance and performance, so it needs to control the manufacturing cost as much as possible, so most of the batteries used in this kind of vehicles are low-cost lithium iron phosphate batteries. With the continuous development of sodium ion battery industry, the cost of raw materials will decrease, and the cost advantage of sodium ion battery will become stronger and stronger. I believe this kind of