KAIST Proposes Copper Sulfide As Electrode Material To Promote The Commercialization Of Sodium Ion Battery

- Aug 15, 2019-

Lithium-ion batteries (LIBs) have been widely used in various electrochemical energy storage applications since the market, including mobile devices, electric vehicles, and energy storage systems (Ess), and are among the most popular types of rechargeable batteries. However, as demand has increased, prices have also increased in the past few years. Due to their high natural reserves, low cost, and similar chemical properties to lithium, sodium-ion batteries (SIBs) are expected to be a replacement for lithium-ion batteries. There is growing interest in SIB batteries, but the commercialization of SIB batteries is far from being realized due to the lack of suitable electrode materials.

According to foreign media reports, researchers at the Korea Advanced Institute of Science and Technology (KAIST) proposed a new strategy to use copper sulfide as an electrode material to extend the cycleability of sodium-ion batteries. The use of this material can promote the high-performance conversion reaction of SIB batteries and is expected to realize the commercialization of SIB batteries.

The team led by Professor Jong Min Yuk confirmed the use of copper sulphide to stabilize the sodium storage mechanism. Copper sulphide is an excellent electrode material with high capacity, high rate and long cycle circulation capability due to its unique resistance to pulverization conversion reaction, thereby promoting capacity recovery. The results show that when copper sulfide is used, the sodium ion battery is charged once a day and the service life can be more than 5 years. Moreover, copper sulphide is rich in natural materials such as copper and sulfur, and is more cost-competitive than lithium-ion batteries. Lithium-ion batteries use lithium and cobalt.

Lithium-ion batteries use intercalation materials such as graphite as the negative electrode, and these materials cannot store a large amount of sodium due to insufficient intercalation spacing. Therefore, people began to explore conversion and alloying reaction materials to meet the high capacity requirements of the negative electrode portion. However, unlike the insertion reaction, in the conversion and alloying reaction, the volume expansion of the material is usually large, and the crystal suddenly changes, thereby destroying the active material, resulting in severe deterioration of the capacity.

The research team found that in the conversion reaction, it plays a key role in achieving the smash-resistant transformation reaction and capacity recovery, semi-coherent phase interface and grain boundary. Copper sulphide undergoes a semi-coherent phase interface through progressive crystal changes, ultimately preventing particle comminution. Based on this unique mechanism, the researchers confirmed that copper sulfide has high capacity and high cycle stability regardless of size and morphology. Professor Yuk said: "The use of copper sulphide can promote the development of sodium-ion batteries, help develop low-cost energy storage systems, and solve the problem of dust."