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KAIST and the International Institute for Applied Systems Analysis Agree to Cooperate
KAIST signed a cooperation agreement with the International Institute for Applied Systems Analysis (IIASA) on October 29, 2014 at the president’s office. Established in 1972 and based in Austria as a non-governmental research organization, IIASA is an international scientific institute that conducts policy-oriented research into global problems such as climate change, energy security, or population aging. IIASA examines such issues and devises strategies for cooperative action unconstrained by political and national self-interest. Dr. Pavel Kabat, the Director General and CEO of IIASA, headed a delegation that visited KAIST to attend the signing ceremony of the agreement. He said, “KAIST has been known as a leading research university, and its strength in the development of green technology and environmental policy will benefit our institution. In particular, we expect to see vibrant exchanges of knowledge and researchers with the Graduate School of Green Growth (GSGG) and the Graduate School of EEWS (energy, environment, water, and sustainability) at KAIST.” The two organizations will implement joint research projects in the diffusion analysis of green technology, the development and improvement of evaluation models to integrate economy, energy, and environment, the development of an analysis system for water resources, and the establishment of academic workshops and conferences. The Dean of GSGG, Professor Jae-Kyu Lee said, “IIASA is a well-respected international organization with accumulated knowledge about analysis and prediction techniques. With this agreement, we hope that KAIST will intensify its research capacity in environmental science and lead education and research in green growth and environmental technology.” The picture below shows Dr. Pavel Kabat, the Director General and CEO of IIASA, on the left and President Steve Kang of KAIST on the right holding the signed agreement with professors from GSGG and EEWS Graduate School including Professor Jae-Kyu Lee, to the right of President Kang.
Rechargeable Lithium Sulfur Battery for Greater Battery Capacity
Professor Do Kyung Kim from the Department of Material Science and Engineering and Professor Jang Wook Choi from the Graduate School of EEWS have been featured in the lead story of the renowned nanoscience journal Advanced Materials for their research on the lithium sulfur battery. This new type of battery developed by Professor Kim is expected to have a longer life battery life and [higher] energy density than currently commercial batteries. With ample energy density up to 2100Wh/kg—almost 5.4 times that of lithium ion batteries—lithium sulfur batteries can withstand the sharp decrease in energy capacity resulting from charging and discharging—which has been considered the inherent limitation of the conventional batteries. Professor Kim and his research team used one-dimensional, vertical alignment of 75nm tick, 15μm long sulfur nanowires to maximize electric conductivity. Then, to prevent loss of battery life, they carbon-coated each nanowire and prohibited direct contact between the sulfur and electrolyte. The result was one of the most powerful batteries in terms of both energy performance and density. Compared to conventional batteries which suffer from continuous decrease in energy capacity after being discharged, the lithium sulfur battery maintained 99.2% of its initial capacity after being charged and discharged 300 times and up to 70% even after 1000 times. Professor Kim claims that his new battery is an important step forward towards a high-performance rechargeable battery which is a vital technology for unmanned vehicles, electric automobiles and energy storage. He hopes that his research can solve the problems of battery-capacity loss and contribute to South Korea’s leading position in battery technology. Professor Kim’s research team has filed applications for one domestic and international patent for their research.
Technology Developed for Flexible, Foldable & Rechargeable Battery
Flexible, Foldable & Rechargeable Battery The research group of professors Jang-Wook Choi & Jung-Yong Lee from the Graduate School of EEWS and Taek-Soo Kim from the Department of Mechanical Engineering at KAIST has developed technology for flexible and foldable batteries which are rechargeable using solar energy. The research result was published in the online issue of Nano Letters on November 5. Trial versions of flexible and wearable electronics are being developed and introduced in the market such as Galaxy Gear, Apple’s i-Watch, and Google Glass. Research is being conducted to make the batteries softer and more wearable and to compete in the fast-growing market for flexible electronics. This new technology is expected to be applied to the development of wearable computers as well as winter outdoor clothing since it is flexible and light. The research group expects that the new technology can be applied to current battery production lines without additional investment. Professor Choi said, “It can be used as a core-source technology in the rechargeable battery industry in the future. Various wearable mobile electronic products can be developed through cooperation and collaboration within the industry.”
Ultra-High Strength Metamaterial Developed Using Graphene
New metamaterial has been developed, exhibiting hundreds of times greater strength than pure metals. Professor Seung Min, Han and Yoo Sung, Jeong (Graduate School of Energy, Environment, Water, and Sustainability (EEWS)) and Professor Seok Woo, Jeon (Department of Material Science and Engineering) have developed a composite nanomaterial. The nanomaterial consists of graphene inserted in copper and nickel and exhibits strengths 500 times and 180 times, respectively, greater than that of pure metals. The result of the research was published on the July 2nd online edition in Nature Communications journal. Graphene displays strengths 200 times greater than that of steel, is stretchable, and is flexible. The U.S. Army Armaments Research, Development and Engineering Center developed a graphene-metal nanomaterial but failed to drastically improve the strength of the material. To maximize the strength increased by the addition of graphene, the KAIST research team created a layered structure of metal and graphene. Using CVD (Chemical Vapor Deposition), the team grew a single layer of graphene on a metal deposited substrate and then deposited another metal layer. They repeated this process to produce a metal-graphene multilayer composite material, utilizing a single layer of graphene. Micro-compression tests within Transmission Electronic Microscope and Molecular Dynamics simulations effectively showed the strength enhancing effect and the dislocation movement in grain boundaries of graphene on an atomic level. The mechanical characteristics of the graphene layer within the metal-graphene composite material successfully blocked the dislocations and cracks from external damage from traveling inwards. Therefore the composite material displayed strength beyond conventional metal-metal multilayer materials. The copper-graphene multilayer material with an interplanar distance of 70nm exhibited 500 times greater (1.5GPa) strength than pure copper. Nickel-graphene multilayer material with an interplanar distance of 100nm showed 180 times greater (4.0GPa) strength than pure nickel. It was found that there is a clear relationship between the interplanar distance and the strength of the multilayer material. A smaller interplanar distance made the dislocation movement more difficult and therefore increased the strength of the material. Professor Han, who led the research, commented, “the result is astounding as 0.00004% in weight of graphene increased the strength of the materials by hundreds of times” and “improvements based on this success, especially mass production with roll-to-roll process or metal sintering process in the production of ultra-high strength, lightweight parts for automobile and spacecraft, may become possible.” In addition, Professor Han mentioned that “the new material can be applied to coating materials for nuclear reactor construction or other structural materials requiring high reliability.” The research project received support from National Research Foundation, Global Frontier Program, KAIST EEWS-KINC Program and KISTI Supercomputer and was a collaborative effort with KISTI (Korea Institute of Science and Technology Information), KBSI (Korea Basic Science Institute), Stanford University, and Columbia University. A schematic diagram shows the structure of metal-graphene multi-layers. The metal-graphene multi-layered composite materials, containing a single-layered graphene, block the dislocation movement of graphene layers, resulting in a greater strength in the materials.
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