KIER Secures Core Technology to Convert Graphite By-products into Anode Materials for Secondary Batteries

The Korea Institute of Energy Research (hereafter referred to as KIER) announced on September 11 that a research team led by Dr. Yujin Han and Dr. Sanghoon Park has developed a core technology that refines graphite by-products generated from industrial processes into "high-purity graphite anode materials" for secondary batteries.

(From left) Seonghoon Park, Researcher, Seungmin Lee, Intern Researcher, Sanseong Jo, Student Researcher, Junhyuk Park, Student Researcher, Yujin Han, Ph.D. Provided by Korea Institute of Energy Research

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Graphite is a key raw material for lithium-ion battery anodes used in electric vehicles. Anode materials account for about 30% of the battery cell's weight, and graphite makes up approximately 10% of battery manufacturing costs.

Currently, more than 90% of commercial graphite for anode materials in South Korea is imported from China, which leads to problems such as sharp price increases and supply instability depending on international circumstances. In fact, in July, the U.S. Department of Commerce imposed high tariffs on Chinese graphite for anode materials, raising concerns about future supply disruptions of Chinese graphite.

To address these challenges, the research team developed a technology to convert domestic industrial by-products into high-value-added anode materials.

By introducing a new process to treat metallic impurities in graphite by-products, the team significantly reduced the number of processing steps and succeeded in producing graphite anode materials with economic viability comparable to commercial graphite anode materials. This achievement is expected to reduce dependence on imported graphite.

The new process developed by the research team is centered on three key steps: ultrasonic treatment to remove surface and internal impurities, followed by surface carbon coating to restore the structure.

To obtain high-purity and high-performance anode materials from graphite by-products, it is crucial to completely remove metallic impurities remaining inside the by-products.

However, until now, strong acid treatment and ultra-high-temperature heat treatment above 2,000 degrees Celsius were required to remove impurities, which led to environmental pollution and high costs. Due to low economic feasibility, there were limitations in utilizing graphite by-products.

Moreover, there was a lack of technology to effectively remove impurities embedded within the graphite, making it difficult to guarantee the performance of regenerated graphite.

In contrast, the technology developed by the research team enables effective removal of impurities even at lower temperatures, ensuring both economic feasibility and environmental friendliness.

Additionally, the graphite anode materials produced with this technology achieved an initial charge-discharge efficiency of 92% and a capacity of 362 mAh/g per gram, which is on par with commercial graphite anode materials. Most notably, even after 200 charge-discharge cycles, 98% of the initial capacity was retained, demonstrating stability comparable to commercial graphite anode materials, according to the research team.

Dr. Han stated, "Graphite has recently become increasingly important as one of the nation's strategic minerals. The technology developed by our research team will serve as a turning point by securing high-value-added anode materials from graphite by-products generated in domestic industries, thereby establishing a foundation for self-sufficiency through stable graphite supply."

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