Manufacturers of secondary (or rechargeable) battery cells have been insisting on very stringent purity specifications from suppliers of cathode materials to ensure a consistent quality output. The purity specifications for cathode materials have been closely guarded as trade secrets with little active scrutiny on the necessity of such high specifications. In response to the demands of cell manufacturers, suppliers of cathode materials have been investing significantly in purifying raw metals, consequently raising the unit cost of batteries.

A research team led by Yong-Tae Kim, PhD, from the Department of Materials Science and Engineering at Pohang University of Science and Technology (POSTECH), in collaboration with Kyu-Young Park, PhD from the Graduate Institute of Ferrous & Eco Materials Technology and the Department of Materials Science and Engineering at POSTECH, and the research team of Woochul Jung, PhD, from the Research Institute of Industrial Science and Technology, has discovered that the purity specifications for cathode materials, as set by cell manufacturers, are overly stringent. Their research demonstrates that streamlining the lithium refining process could substantially reduce the unit cost of batteries. The research findings are published in Nature Communications.

Get training in Chemical Hygiene and earn CEUs.

One of over 25 IACET-accredited courses in the Academy.

Chemical Hygiene course

In this research, the team delved into the impact of lithium raw material purity on the production and performance of secondary battery cathode materials. Conventionally, it’s assumed that impurities in lithium materials hamper secondary battery performance. Therefore, the goal is to manufacture lithium materials with purity of at least 99.5 percent. Nevertheless, the team uncovered that the presence of approximately one percent magnesium (Mg) impurity in the lithium raw material actually enhances process efficiency and prolongs the secondary battery’s lifespan. Through their experiments, they demonstrated that utilizing low-purity lithium, not entirely rid of impurities, could reduce secondary battery production costs and carbon dioxide emissions by up to 19.4 percent and nine percent, respectively.

Yong-Tae Kim, PhD, who led the research, stated: “Secondary battery cell manufacturers need to reassess whether their current cathode material specifications are too stringent.” He further remarked, “Considering unconventional approaches could offer a fresh strategy against China’s aggressively low prices.”

-This news release was originally published on the Pohang University of Science and Technology website and has been edited for style and clarity.