What is sodium-ion battery?

A sodium-ion battery is a rechargeable battery consisting of a positive electrode, a negative electrode, an electrolyte, a collector fluid and a diaphragm. It uses sodium ions (Na+) as the charge carrier instead of conventional lithium ions (Li+) and works mainly by moving sodium ions between the positive and negative electrodes. It works very similar to lithium-ion batteries, even the internal structure of the battery is basically the same, they have two electrodes (one positive and one negative) separated by an electrolyte. During charging, sodium ions move from the positive electrode through the electrolyte to the negative electrode and are stored there. During the discharge process, the sodium ions move back to the positive electrode and generate current. In other words, the sodium ion is replaced by the lithium ion. Sodium ion batteries are attractive because they use abundant and inexpensive sodium resources, while lithium is a relatively rare and expensive metal.

One of the challenges of sodium ion batteries is that sodium ions are larger than lithium ions, which means that the materials used in the batteries must be able to accommodate the larger size of sodium ions. This requires finding suitable electrodes and electrolytes. Research to develop new materials and optimise the performance of sodium ion batteries is ongoing.

1.How does sodium ion batteries work?

Sodium-ion batteries work by using the movement of sodium ions between two electrodes, a positive electrode (cathode) and a negative electrode (anode), through an electrolyte.

During charging, the battery is connected to a power source, and the movement of electrons in the external circuit causes the sodium ions to migrate from the cathode to the anode. At the same time, electrons are transferred from the cathode to the anode through the external circuit. The anode material is usually made of a material that can intercalate (i.e., insert and remove) sodium ions, such as graphite, while the cathode material is usually a metal oxide, such as sodium cobalt oxide (NaCoO2).

During discharging, the battery is disconnected from the power source, and the sodium ions move back to the cathode through the electrolyte, creating a flow of electrons in the external circuit. The amount of energy that can be stored and released depends on the materials used in the battery, the size and surface area of the electrodes, and other factors.

2.Sodium ion battery advantages and disadvantages

Sodium-ion batteries have several advantages and disadvantages compared to other types of rechargeable batteries, such as lithium-ion batteries. Here are some of the main advantages and disadvantages of sodium-ion batteries:

Advantages:

a. Abundant and inexpensive. Sodium is more abundant and cheaper than lithium, which has the potential to make sodium ion batteries more cost effective.

b. Low risk. Compared to some other battery chemistries, sodium ion batteries have a lower risk of thermal runaway, which can make them safer to use.

c. Environmental impact. Sodium ion batteries have a lower environmental impact than some other chemical batteries because sodium is more abundant and less toxic than some other metals.

d. Very fast charging speed, it is said that at room temperature just 15 minutes of charging, the power can reach 80%.

e. The working temperature span of sodium batteries is also very large, and they can have a discharge retention rate of over 90% in a low temperature environment of -20℃.

Disadvantages：

a. Low energy density. The biggest defect of sodium batteries is the low energy density, some data show that the energy density of sodium ion battery monomer is 100-150wh/kg, less than the lower limit of 180wh/kg in the Chinese industry requirements standards, which means that the same range of two batteries, sodium batteries are larger and heavier than lithium batteries.

Tesla Model 3 currently uses a ternary lithium battery energy density of 260Wh/kg, Tesla’s third generation 4680 battery energy density can reach 330Wh/kg. sodium ion battery energy density is even less than half of it, energy density, determine the same weight, the same volume, whose battery pack can last longer. How to improve the energy density of sodium ion batteries, which is a major problem in front of many companies. If the energy density problem can not have a breakthrough progress, at least in the future for a long time is not possible to completely replace the lithium battery.

b. Larger size and weight. Because sodium ions are larger than lithium ions, this means that the materials used in the batteries must be able to accommodate larger sizes of sodium ions, and sodium ion batteries may require larger electrodes and electrolytes, which may make them larger and heavier than lithium ion batteries.

There are three types of cathode materials available for sodium ion batteries, layer oxide, polyanion and Prussian blue type materials. For example, Ningde Time’s first generation sodium battery uses Prussian blue-like materials, which are low-cost, simple to synthesize, highly designable, and have high theoretical gram capacity and multiplier performance, but have the disadvantages of difficult water removal, low cycle life, poor actual multiplier performance, low bulk energy density, large voltage polarization, and risk of thermal runaway.

The most fatal problem is the production and processing process, if not handled properly extremely easy to form crystalline water, and this problem is currently difficult to solve. It is said that Ningde Times has suspended the development of sodium ion batteries with Prussian blue-like materials, and is now trying to reach mass production with layered oxide and polyanionic materials. The layer oxide crystal structure is similar to the ternary cathode material, the advantages of which are high energy density, excellent cycling performance, good multiplier performance, the disadvantages are poor stability in the air, the slurry is easy to jelly, gram capacity play unstable. Polyanionic materials, on the other hand, are recognized for their high cycle life, high theoretical operating voltage, and good thermal stability, with the disadvantages of low energy density and high raw material cost.

c. Performance and Stability. Sodium ion batteries are still in the early stages of development, and their performance and stability may not be as well understood as other battery chemistries, such as lithium ion batteries. The true cost of the follow-on and what the real-world experience will be are also unknown. What’s more, although lithium carbonate is currently very expensive, its market is fluctuating, and once we see a breakthrough in sodium ion batteries, it is bound to be a significant price reduction and sodium batteries will lose any advantage.

In general, sodium ion batteries are a direction of research and development, but further research and development is needed to improve their performance and address their limitations. Ternary lithium batteries and lithium iron phosphate batteries are sure to remain the absolute mainstream batteries for a long time.

3.Sodium ion batteries vs. lithium ion batteries

Sodium-ion batteries and lithium-ion batteries are both types of rechargeable batteries, but they have some key differences in their chemistry and performance. Here are some of the main differences between sodium-ion batteries and lithium-ion batteries:

a. Materials: Sodium-ion batteries use sodium ions as the charge carriers, while lithium-ion batteries use lithium ions. Sodium is more abundant and less expensive than lithium, which could potentially make sodium-ion batteries more cost-effective.

b. Energy density: Lithium-ion batteries typically have a higher energy density than sodium-ion batteries, which means they can store more energy in a given volume or weight. This makes lithium-ion batteries better suited for portable devices where size and weight are important.

c. Performance: Lithium-ion batteries have been extensively researched and developed, and they generally have better performance and stability than sodium-ion batteries. Sodium-ion batteries are still in the early stages of development, and their performance and stability are not yet well understood.

d. Safety: Sodium-ion batteries have a lower risk of thermal runaway compared to some lithium-ion batteries, which can make them safer to use.

e. Environmental impact: Sodium-ion batteries have a lower environmental impact than some lithium-ion batteries because sodium is more abundant and less toxic than lithium.

f. Cycle life. The current cycle life of sodium-ion batteries is much lower than that of lithium-ion batteries, which will certainly increase the number of maintenance and replacement of sodium-ion batteries in use. Sodium batteries are generally between 1000-3000 times. In contrast, the cycle life of lithium iron phosphate batteries is between 3000-10000 times.

In general, compared with the industry is more mature lithium batteries, sodium battery industry is far from the formation of large-scale mass production, there is currently an industry chain is not a sound bottleneck, resulting in the current sodium ion batteries than lithium iron phosphate prices are also high.

Industry insiders said this: “Whether it is energy storage or other areas, sodium ion batteries at this stage is difficult to completely replace lithium batteries, because the application areas between the two are complementary, the current market to the sodium ion battery positioning is a potential alternative to lithium-ion batteries, is a supplement to lithium batteries, rather than a replacement.”

Luoyang Tianhuan energy technology Co., LTD

website:www.lythbattery.com

E-mail:info@lythbattery.com