World-class research accomplishments by faculty members in the Department of Materials Science and Engineering, College of Engineering, have been published consecutively.

Professor Kyung-jin Lee and his international joint research group developed a technology for next-generation semiconductors that saves 95% of the power consumption. 

Professor Yong-mook Kang proposed a breakthrough to overcome the limits of secondary battery charging capacity.

▲ Professor Yong-mook Kang (left) and Professor Kyung-jin Lee of the Department 

of Materials Science and Engineering.

Two professors in the Department of Materials Science and Engineering, College of Engineering, are drawing people’s attention as they have published in the world’s best journals their research accomplishments on future components and materials, in this case, next-generation semiconductors and secondary batteries.

Professor Kyung-jin Lee in the Department of Materials Science and Engineering, College of Engineering, developed through an international collaboration (Professor Teruo Ono and Doctor Duck-ho Kim at Kyoto University, Japan; Professor Se Kwon Kim at University of Missouri; Professor Kab-jin Kim at KAIST) a world’s first source technology that can save more than 95% of the power consumed by MDW (Magnetic Domain Wall)-MRAM (Magnetic Random Access Memory) through the application of a new magnetic material.

The results of the research were published in Nature Electronics, a prominent international journal, on September 18 in London, UK.

A DRAM (Dynamic Random Access Memory) has advantages such as an ultra-fast data process, high-density storage and low-power operation. However, power should be continuously supplied to a DRAM for data storage, even when the device is not in use. The MDW-MRAM was developed to overcome the limitations of DRAMs. However, the conventional MDW-MRAM requires a high drive current for high-density data storage.

Professor Lee replaced the conventional ferromagnetic material for MDW-MRAM with a new ferrimagnetic material, which increased the drive current efficiency by more than 20 times and decreased the power consumption by more than 95%.

Professor Lee said, “The results demonstrated the possibility of addressing the high power consumption, which has been an important problem of next-generation MDW-MRAM technology. Since MRAM satisfies all the non-volatility, high density and low power consumption requirements, our technology will have a ripple effect on the development of Fourth Industrial Revolution technologies, including AI (artificial intelligence), autonomous driving and the IoT (internet of things).”

Professor Lee’s research project was supported by the Samsung Future Technology Development Program of Samsung Electronics in December 2017.

The joint research team of Professor Yong-mook Kang in the Department of Materials Science and Engineering, College of Engineering, and Professor Won-sub Yoon at Sungkyunkwan University successfully developed a technology to overcome the limits of secondary battery charging capacity.

The results of the research were published in Nature Communications, a prominent international journal, on September 2 in London, UK.

Secondary batteries have been applied to mobile phones and electric vehicles. The duration of secondary battery use is mostly dependent upon the performance of the positive electrode material.

The positive electrode materials that are currently used for secondary batteries have a structure in which the positive ion layers transporting electricity and metal oxide layers are laminated layer by layer. However, when over a certain number of positive ions are transported during the battery charge/discharge process, the layered structure collapses and fails to recover. The irreversible structural change has been pointed out as the limitation of the performance of secondary batteries because it prevents the full use of the initial charging capacity of positive electrode materials.

Professor Kang’s group focused on the finding that birnessite, a manganese-based oxide, may be used to control the interlayer structural properties by changing the amount and position of the crystal water existing between the layers. His group made the structural change occurring in the charge/discharge process reversible, demonstrating the possibility of fully utilizing the initial charging capacity.

Professor Kang explained the significance of the research, “The study first proposes a new paradigm that enables one to essentially overcome the structural change of positive electrode materials occurring in the charge/discharge process.” He added, “If the reversible structural change can be extensively applied to various layered materials, the development of secondary battery positive electrode materials will be accelerated to reach almost the theoretical performance limit.”

The research was supported by the Free Research Theme Project of the Samsung Future Technology Development Program of Samsung Electronics in June 2017.