Korea Advanced Institute of Science and Technology said Wednesday it has developed a new material that enhances the energy density of lithium-ion batteries by 20 percent while maintaining their stability.

According to a research led by Cho Eun-ae, materials science and engineering safety professor at KAIST, lithium-ion batteries that contain 80 percent nickel inside cathodes demonstrate energy capacity of 200 ampere-hours per gram. However, the newly developed cathode materials can accommodate 20 percent more lithium ions and exhibit energy capacity of as much as 250 ampere-hours per gram.

Cathodes are one of the four key components of lithium-ion batteries including anodes, separators and electrolytes. The higher the ratio of nickel inside cathodes, the more powerful but less stable lithium-ion batteries become.

“If existing high-nickel cathodes could accommodate 100 lithium ions, the new cathodes can contain 120 lithium ions, providing greater energy to batteries,” Cho told The Korea Herald.

Cho added that lithium-rich cathodes haven’t been commercialized yet because when too much lithium-ions visit cathodes, they react with oxygen and compromise the structure of the cathodes.

However, Cho solved the instability issue by coating the lithium-rich cathodes with a metal called vanadium.

According to the research, lithium-ion batteries coated with vanadium maintained 92 percent of initial performance after charged and discharged 100 times, while uncoated ones preserved 74 percent of initial capacity.

Also, cathodes coated with vanadium returned to their original state at 81 percent level after charged and discharged once, while uncoated cathodes recovered their original state at 69 percent level in the same condition.

“Vanadium is not a common material, but as a extremely small amount is used for coating cathodes, it’s unlikely to drive up the costs of lithium-ion batteries,” Cho said.

By Kim Byung-wook (kbw@heraldcorp.com)