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2017-10 02 Headline News

[Academics][Researcher of the Month] Producing Energy Through a Single Thread

'Lack of energy’ is an issue the whole world is focusing on. Various countries are searching for effective renewable energy and new materials that could replace the current energy sources. Professor Kim Seon-jeong (Department of Biomedical Engineering) discovered a new material every researcher was looking for. Kim's paper, “Harvesting electrical energy from carbon nanotube yarn twist” introduces the world’s first new material, which can produce energy through slight movements. Kim explains the concept of his new material Professor Kim’s research team started its first project in 2006 on artificial muscle. However, after his research, Kim realized its limitations as they were only able to move through an external energy source. Therefore, he thought of a new idea that the muscle would be more effective when it is able to produce energy by itself. Carbon nanotube is a new material which is a type of conductor and has a diameter of only a few nanometers. This material was made as a thread in the artificial muscle. However, when these threads were finely twisted into one direction, they were able to produce energy by itself through its contraction and relaxation without an applied voltage. Being made into a spring, their length can be changed as much as 30 percent on average. This new material, named as ‘twistron harvester yarn’, allowed a chance for the muscle to move by itself without a separate power source. This twistron harvester yarn looks and acts as if it were an ordinary thread. This states that making clothes out of this material is possible. Once this comes into realization, this would give a boost in making wearable devices, as producing electricity without an energy source is possible. Moreover, this thread is possible to use inside water, giving another possibility of an effective alternative energy. This has already been tested in the East Sea of Korea. Kim’s research team made a model consisting of a glass bottle connected with an electrode, the thread, a balloon, and an equipment that could measure electricity. As the twistron harvester yarn contracted and relaxed, electrical energy was verified from the ocean. Kim showed great passion in the research he was conducting. This research on the twistron harvester yarn was his fourth research. He has been working on artificial muscles for the past nine years before he started this research. “I didn’t start this research solely to find the twistron harvester yarn. I felt the limitations within the research I conducted earlier and was seeking for development,” reminisced Kim. He explained that he wasn’t the only person who conducted the research. Eight teams from three different countries worked on this new material for two years to deduct a better result. “We had a meeting through Skype every week, along with frequent visits to each team. Everyone had great passion and interest towards this research, and I believe that shows the firmness of this research,” said Kim. "Reach towards your own interest!" Kim also emphasized the attitudes Hanyangians should have towards their life. Even though he mainly teaches graduate school students, he wished all students could find what they truly wish to do. “Find something unique of your own. Find something you enjoy, and then you will be able to continue on with whatever you are doing. There are countless routes for all students. I wish students would keep challenging themselves to make the greatest results of their own,” wished Kim. Just as his words, Kim will continue with his work with great passion, for even better convenience for global citizens. On Jung-yun jessica0818@hanyang.ac.kr Photos by Kim Youn-soo

2017-08 31

[Academics][Researcher of the Month] What Makes People Pro-Environment? (1)

“Whenever I go on a trip or big festivals, I always worry about all the trashes people throw away. It’s just too much.” Professor Hyun Sung-hyup of the Division of Tourism recently published his paper, "Fostering customers’ pro-environmental behavior at museum". The paper thoroughly investigates the affective and cognitive factors of individuals visiting museums and analyzes which factor has the most impact on their pro-environmental intentions. Hyun emphasized that most people are very environmentally friendly in their house. They recycle well, try not to waste food or water. However, the point is that the very same people behave entirely differently from the moment they leave their house. Trashes are disposed not separately, which then has to be combusted, letting carbon into the air. Tissues, water, food and all kinds of resources are wasted. Hyun wondered what is behind the people’s paradoxical behavior. He also wanted to figure out what needs to be triggered in order to resolve such paradox and to motivate eco-friendly behavior from the general public. A table showing relations of each factor and their effects (Photo courtesy of Hyun) Over the course of a year, Hyun went to a broad range of museums which deal with themes like art, war, and tradition to interview, survey and observe the visitors. From the data collected from 321 tourists, he ran statistical analysis simulation program to construct a conceptual framework that can predict people’s behavior in public spaces. He also sought for professional advice from other fields such as environmental specialists or professors in engineering for further insight. Based on his field research with dozens and hundreds of related papers he studied, Hyun found out that ‘Environmental Knowledge (EK)’ out of five cognitive factors, was the most significant factor in determining one’s environmentally responsible decision-making process. Hyun is explaining the process of his research. Hyun asserted that environmental education on a regular basis is essential. People with more professional knowledge on the vulnerability of the environment or the impact of their action is more inclined to show consistent behavior both in and outside of their home. "It seems like a lot of people lack education regarding the environment in both public and private sectors," said Hyun. Lamenting at such reality, Hyun wishes environmental education to be part of the public education curriculum in the near future. When asked what inspired him to become a researcher in Tourism, Hyun smiled and answered that his professors during college years influenced him a lot. “Hanyang University offers the best curriculum on Tourism, with respectful professors. I always looked up to them.” Hyun said he decided to study further because there are so much intriguing topics to research in the field of Tourism. He encourages future researchers in the field to boldly try out, because tourism is very future oriented, interdisciplinary and economically significant field of study. Hyun himself plans to vigorously research further on issues related with environment and tourism. “Researching while lecturing, mentoring and living personal life is tough but I still enjoy it,” said Hyun, with affection to his work. Kim So-yun dash070@hanyang.ac.kr Photos by Choi Min-ju

2017-07 30

[Academics][Researcher of the Month] World Class Solar Cell Developed

Professor Kim Eun-kyu of the Department of Physics is July’s Researcher of the Month for his active role in spreading knowledge in the field of physics. In his paper, “Iodide management in formamidinium-lead-halide-based perovskite layers for efficient solar cells”, Kim explains how he has created the ‘perovskite solar battery’ with the best efficiency in the world. Perovskite batteries have high efficiency and low production cost which is how it is gaining interest for the next generation solar energy source. Kim is explaining about the perovskite solar battery. Perovskite is material created out of anion, cation, and halide and is used inside the solar battery to create electricity. Kim has carried out his study along with Ulsan National Institute of Science Technology (UNIST) and Korea Research Institute of Chemical Technology (KRICT) and the paper has been introduced in the world renowned academic journal, Science. The research has been carried out through the support of Ministry of Science, ICT and Future Planning. The key theme of the research has been that through the control of halide, efficiency was to be raised from 20.0% to 22.1%. Currently, solar batteries are created with silicon materials but with the newly developed technology, new solar batteries could produce the highest efficiency with half the cost. Not only could it be used in the solar batteries, but they could also be used to produce new and renewable energy in the future with further integration of different technologies. Graphs showing the efficiency of the solar battery at 22.1% (Photo courtesy of Kim) Kim has started this study since all types of batteries should implement high level of efficiency. With high efficiency follows the lower production cost which was why this was important for the commercialization of the solar battery field. Kim and his research team are the best in the field currently showing the highest level of efficiency and still working for better technology. Although the technology itself has been developed to produce the most efficient solar batteries, mass production and commercialization problem is yet to be solved. Kim and his team are currently working on the perovskite battery to further test its safety and to control the halide. Although Kim and his research team have already reached their goal of creating the efficient battery and printing their paper on Science, further studies will be carried out to make the lives more convenient for people. Kim wishes to develop a more efficient solar battery in the future. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Kim Youn-soo

2017-07 04

[Academics][Researcher of the Month] Ground Breaking Advancement in Medical Magnetic Robot

The era of robots wandering inside a human body for medical treatments is about to face our generation. Though the research is still in the process of developing magnetic fields and improving robots, the actual application of the medical robots is expected to occur in a decade. In his research “Magnetic Navigation System Utilizing Resonant Effect to Enhance Magnetic Field Applied to Magnetic Robots,” professor Jang Gun-hee of the Department of Mechanical Engineering proposes the improvement of the magnetic navigation system (MNS) via RLC (stands for resistor, inductor, and capacitor) circuit in the hope of its medical application. Generation of strong magnetic fields in high frequency When doctors treat for blood vessels related illness like coronary artery diseases or have to execute endoscopic surgeries, they often use catheters (thin tube made from medical grade materials) controlled by their hands and medical, empirical sensations. However, these catheters don’t have the sufficient controllability for the physicians due to their long, flexible wires. “The main point of this research was to minimize the surgical errors that these catheters may incur. So, we decided to make magnetic robots that are microscopic enough to wander inside our vessels,” said Jang. The types of robots currently in technical development are various- fish type robots, wobby-like robots, swimming robots, helical robots, and more. However, the magnetic robots especially intrigue the academia. “Compressed springs inside the robot will spread out, enhancing its drilling capability inside the vessels, which its movements will be guided by the magnetic system. Improvements in this MNS are significantly vital, as every mechanical motion of the magnetic robots is proportional to the external magnetic field,” emphasized Jang. Jang has been working on the magnetic navigation system research for about 12 years, which currently resulted in the torque magnetic field on the right. Through the experiments to unclog the blocked area of tubular environments, Jang and his students researched on a novel MNS with the resonant effect of the RLC circuit. “Simply saying, these robots with the MNS have magnets. When the north pole of the magnet approaches another north pole, it will push, and vice versa in the case of the south pole. This is the simplistic picture of how the magnetic robots and the MNS are working,” said Jang. Advancement to this fundamental phenomenon, Jang refers to the "closed right hand rule" (Ampere Law that relates the net magnetic field along a closed loop to the electric current passing through the loop) to explain his research. “In our newly developed MNS, inside the diameter of 50 centimeters wide spherical environment, we can create and control strong magnetic field in any direction which eventually generates useful various mechanical motions of the magnetic robots,” highlighted Jang. Another unconventional discovery of Jang’s research is the application of resonant frequency in the RLC circuit to amplify the magnetic field of the robot. RLC stands for resistance, inductance, and capacitance which all are in the influential relationships in science. When the alternating voltage is increased, the resistance should be divided to flow the current. However, as the alternating frequency of voltage increases, the current decreases due to the inductance of the coil. “We eliminate the effect of inductance with the application of varying capacitance that leads to maximizing the current and the magnetic field in high frequency,” explained Jang. This phenomenon was able to generate fast drilling motion of the magnetic robot to unclog the blocked area of blood vessels. Furthermore, application of the MNS developed a crawling robot that can also deliver drugs into a human body, which Hanyang University gained its international patent of. (Video courtesy of Jang) Hopes for the scientific improvement It has been a decade since Jang has been working on this magnetic robot research. The beginning of all dates back to when his mother was hospitalized due to her coronary artery disease in the heart. “The doctor told me that the illness is genetic and I may also be in danger. So, I thought that rather than believing in the doctor’s hand and the catheter, I should believe in science to develop this surgical methodology and first test on me,” said Jang. During the several years that Jang has been working with his students, he also began to long for fostering his students and their success. “I was always interested in the concept of a motor since I was young. This academic desire eventually led me to become a scholar, but since I became a professor of many students and a father of two daughters, I began to be intrigued to their life-long academic achievements,” reminisced Jang. Ph.D students of the Department of Mechanical Engineering- Lee Won-seo (left) and Nam Jae-kwang (right), also participated in the research with their professor Jang. It is estimated that after more technical amendments of this mechanical robot, it will be capable of testing on animals, and then applied to human surgeries, which will take about a decade. During this journey to scientific achievements, Jang realized that efforts are what science really value. “Just like my students who endeavored all their desires to science to leap higher, I hope that the South Korean scientific academia will also hope for the brighter future,” reminded Jang. Kim Ju-hyun kimster9421@hanyang.ac.kr Photos by Kim Youn-soo

2017-05 30

[Academics][Researcher of the Month] Fusion Research in Enlightenment

Professor Choi Dong-ho of the Department of Medicine is June’s Researcher of the Month for his active role in developing knowledge in the field of medicine. In his paper, “Design and Fabrication of a Thin-Walled Free-Form Scaffold on the Basis of Medical Image Data and a 3D Printed Template: Its Potential Use in Bile Duct Regeneration”, Choi explains how he has created the bile duct, a body part that exports bile from liver to duodenum with 3D printer and being able to successfully conduct clinical demonstration on rabbits. Professor Choi explains about the 3D printing and its relation to artificial organs. For 20 years, Choi has been working on stem cell research which has eventually led to the stage of creating artificial organs with 3D printing techniques. Bile duct is one of the very sensitive body parts where it is hard to fix once problem occurs. Although there are artificial blood vessels, there has been no artificial bile ducts created. What makes it so complicated to make is that since bile is carried through the bile duct, it shrinks as time goes on if created with the material as commonly used as Gore-Tex. The material should be sturdy enough to withstand the bile, and it should be flexible enough to be sewed up as well which is definitely not an easy task. Process of creating bile duct through 3D printing (Photo courtesy of Choi) The diagram above depicts the process of creating bile duct. It first goes through the data acquisition through MRI images and 3D designing. As some cells are mixed up to the mold, it grows into the shape and size as designed. Important technique here is to develop the bio ink that congeals once it flows out of the 3D printing machine. Creating hydrogel and mixing up the stem cells to it is another important task to be completed. "I hope that what I create can be of help to people." Choi’s team is currently in the stage of obtaining patent in the techniques to create artificial organs through 3D printing. Since there are tremendous types of researches to be carried out through his studies, ranging from stem cell reprogramming to drug screening, Choi wishes that creating safe artificial organs in the end is what he wishes to achieve. “I am still doing translational research with various other departments and I hope that what I create can be of help to not only the patients, but even for my family as well in times of emergency,” concluded Choi. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Moon Hana

2017-05 02 Important News

[Academics][Researcher of the Month] Simulation of Human Movements

Professor Kwon Tae-soo. Human movements are much more intricate and complicated than it seems. Many attempts were done to portray moving human actions by computer program and animation. Those attempts were partly successful until now, yet with certain limitations. Professor Kwon Tae-soo of the Department of Computer Science & Engineering is greatly interested in simulating human motion. In his recent paper, “Momentum-Mapped Inverted Pendulum Models for Controlling Dynamic Human Motions”, he explains about how physics can be applied into animating human movement and be used in its development. Simulating human animation is a complicated business. Most of the animation we see in games and movies is based on a technical method called motion capture. Motion capture is a method of simulating motions by attaching sensors to a moving object and tracking the information of the movements, then analyzing its numerical data. However, movements of these animations have certain limits because of its foundation which merely consists of pre-captured motions. Therefore, in order to exceed this disadvantage, quite a few research was done utilizing physics into developing animation using Inverted Pendulum Model, or IPM, which analyzes human motions through controlling robots by computerized robot simulator program. Although IPM became a potentially alternative method of producing simulation of motions, it had a problem of producing unnatural movements of characters. Kwon, who was aware with this limitation of IPM, developed a new form of IPM called Momentum-Mapped Inverted Pendulum Models (MMIPM). The similarity of IPM and MMIPM is that both methods use two kinds of robot, a simple kind of robot, an upside-down kind of pendulum which is comprised of a cart and a pole, and a humanoid. Due to the difficulty of controlling a complex humanoid, the simple robot is first used. By using conversion after mapping the present state of simple robot, signals for controlling the humanoid can be calculated. The difference of the quality of movement of characters between IPM and MMIPM. (Photo courtesy of Kwon) One of the main contrasts between IPM and MMIPM is the way mapping is done. While mapping for IPM must use both the center of mass and center of pressure of the robot for mathmatical differentiation, momentum-mapping uses the center of mass. Differentiating one time instead of two is highly beneficial because the quality of signals improve. In addition, if two feet of the humanoid are above the ground, center of pressure becomes absent, mapping with conventional IPM method become impossible, whereas mapping with MMIPM is still possible. MMIPM also concentrates on modeling the changes of postures and how much the human body is tilted during performing certain actions. Therefore, because of the differences or technical improvements of MMIPM compared with IPM, expressing more natural and difficult movements can be realized. As a result, Kwon could successfully produce more natural movements of running, and complex acrobatic motions such as spinning, backflip, and handstand. Character performing a backflip. (Photo courtesy of Kwon) Character performing a handstand. (Photo courtesy of Kwon) Professor Kwon’s future studies also focus on human movements, which are reenacting motions of soft parts of the human body, such as fat. According to Kwon, the technology which is used for today’s animations and games is from a decade ago. “Although at first a game with great graphics may seem like something big. However, when you start an online game, soon you will realize that the actions of your characters are mere repetitive movements, ” said Kwon. Through his study, Kwon aspires to broaden the limits of present day game-play and animation. “My ultimate objective is enabling game characters to perform unexpected movements when players enjoy unpredictable game plays,” Kwon revealed. Jang Soo-hyun luxkari@hanyang.ac.kr Photos by Choi Min-ju

2017-05 01 Important News

[Academics][Researcher of the Month] How ‘Fit' Are You With Your Boss?

For a higher competency of a company or a corporation, factors like personality, values and goals that employees and leaders prioritize were focus of a research in management or psychology studies. It has been thought that such factors should be met between a leader and an employee for higher effectiveness in a company. Rather than determining how ‘fit’ a leader and an employee is under the standards of aforementioned aspects, there has been a new perspective suggested by Professor Shin Yu-hyung of the Department of Management. Appointed as one of the researchers of the month, her recent paper, “Does Leader-Follower Regulatory Fit Matter? The Role of Regulatory Fit in Followers’ Organizational Citizenship Behavior” discusses the two different concepts, ‘promotion focus’ and ‘prevention focus’ and how it works between a leader and an employee. From her doctoral course, Shin realized how aptitude and characterisitcs of people are important. The core of Shin’s research is one’s different strategic intentions, which can be divided into prevention focus and promotion focus. Promotion focus refers to a strategy to bear risks for positive outcome. Thus employees with promotion focus would put themselves into challenges for better results in their tasks even if they have to bear risks during the process. On the other hand, employees with prevention focus will contain themselves inside a security zone, putting their biggest effort to avoid the worst outcome. Thus, unlike the ones with promotion focus, they would not try to change the conditions in the given environment and will aim to accomplish the goals within the boundary of rules or conditions. For example, consider two college students in their 3rd year. Both of them studies hard to get better GPAs but their focus can be different. Student A with promotion focus studies hard because A wants to get higher scores to apply to a company he or she wishes. Student B with prevention focus would only study hard merely to avoid an F on his or her GPA. In the paper, Shin tried to examine and demonstrate such relevance with Organizational Citizenship Behavior (OCB), which refers to discretionary and extra-role behavior that is considered to increase overall effectiveness in an organization, a company in this case. What Shin chose was to prove it through a survey. She chose 140 leaders and 640 employees from different fields of Korean domestic companies. The questions mainly asked of one’s attitude to different focus, whether it is more toward promotion or prevention. As a result, Shin was able to witness different focus strategy each employees and their leaders take. According to the graph, the allignment of leader and follower (employee) proves the highest effectiveness of OCB. (Photo courtesy of Shin) Analysis of the survey showed several facts. First, when an employee pursues promotion focus, his or her fit with a leader showed less significance. “People with high promotion focus are the ones who tries to break a conventional frame or a box, which makes their fit with their leaders less necessary. Only their degree of the focus will determine their degree of accomplishment,” explained Shin. However, the importance of ‘fit’ was shown in the case of an employee with high prevention focus. In this case it has been proven that the more one is fit with his or her leader, the better accomplishment one can make. “As people with prevention focus tries to work most effectively within the given frame, they try to cooperate and negotiate well with others while abiding by the law, which makes the fit with their leaders more important,” said Shin. While researches on regulatory fit between leaders and employees have been done for a long time, the different perspective Shin suggested is getting credits for positive feedbacks of the paper. In the same line, Shin is working on how various styles of working can affect the outcome. In a case like where an employee is the one who tends to take more steps in completing his task while his or her leader is the one who is always chased by the dead line. As the cooperation between a leader and an employee is always important for a successful company, Shin expects the research could positively affect and motivate more innovative management studies. Shin said she will keep on researching to contribute to HYU and Korea's good brand image. Yun Ji-hyun uni27@hanyang.ac.kr Photos by Kim Youn-soo

2017-04 03 Important News

[Academics][Researcher of the Month] Detecting Ultra-Sensitive Benzene

Professor Kim Hyoun-woo of the Division of Materials Science and Engineering is April’s Researcher of the Month, for his active role in exploring the field of materials science and engineering. In his paper “Ultra-sensitive benzene detection by a novel approach: Core-shell nanowires combined with the Pd-functionalization”, Kim explains how the detection of benzene gas has become much more efficient than ever. The palladium being extra sensitive to benzene gas has been the key to the detection technique which has drawn attention in this field. Kim has discovered the link between palladium and benzene gas. The Pd-functionalized SnO2-ZnO C-S NW is the substance developed by Kim in order to detect benzene, a toxic gas. Since nano-sized palladium particles are added on a cell with SnO2 and ZnO covered on top, the sensor produces a spillover effect, distributing the benzene gas particles along the conduction band. The effectiveness of Kim's model is proven through the gas response. (Photo courtesy of Kim) This is important since benzene gas can be found in everyday life. It is inside cigarette smoke, smog, exhaust fumes and may be found in new houses, creating sick house syndrome. Through Kim’s finding, this benzene gas, which could be lethal to human lives, can be spotted in a much more sensitive manner. Since the sensors and cells created in a smaller size would lead to higher sensitivity, the particles have been selected in nano-sizes. The only problem that could arise with this sensor is that it depends heavily upon the selectivity of which gas it wants to detect. The compatibility between different particles could create great results as Kim has found out in the case of palladium and benzene, while in other cases, disastrous results may be spawned. Kim explains how his model works. Kim wishes to develop better usage of sensors than those that are being distributed in every day life as of now. “I want to find the best usage of a new sensing principle totally different from the current ones,” said Kim. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Choi Min-ju

2017-02 28 Important News

[Academics][Researcher of the Month] Blue Ocean of Materials Science

Conspicuous or not, our surroundings play a crucial role in navigating our health, holding accountability for small and big degenerations for mankind’s physical wellbeing. Among all, two indispensable elements in our life, air and water, have slow and accumulative effect on the health of the population. Professor Kim Ki-hyun (Department of Civil and Environmental Engineering), whose studies focus on environmental pollution, delineated the means of applying advanced materials in his review paper “Carbon nanotubes: a novel material for multifaceted applications in human healthcare.” Carbon nanotubes in biotechnology As modern material technology has been advancing considerably, its application seems ever-expanding in diverse fields, with nanomaterials as the convenient and indispensable companion. Based on a research paper conducted by other scholars, Kim wrote another, centralizing on the uses of carbon nanotubes (CNT), an emerging nanomaterial that is seeing the light in the biomedical and environmental fields. Its application is versatile: drug delivery, sensing, water purification, composite materials, and bone scaffolds. More specifically, CNTs could be used to alleviate myocardial infarction by enlarging clogged blood vessels, expediting drug delivery, and organizing bone structures in needed parts. Kim outlines his review paper on the application of carbon nanotubes in the biomedical field. Despite all the medical benefits, advanced materials including CNT also have the potential to bring adverse effects. As alien substances could disturb immune or antibody responses, the body functions to react against them. Especially, in case of new materials, unprecedented resistance could occur, and thus their potential impacts must be taken into consideration through attentive examination for possible toxicity. Nonetheless, as long as the criteria are met, CNT and other materials could spark revolutionary breakthroughs that would change the future of mankind. “I think that endless developments are yet to come in the field of materials science to help other research fields like environment and human health flourish. Better materials in terms of cost efficiency and functional effectiveness would be improved while there is yet no limits to such developments. Materials science and nanomaterials would not only be fruitful in biomedical fields but also environmentally,” commented Kim. His interest in new materials are extended toward environmental progress, starting with the sensing of pollutants and purifying polluted medium. The blue ocean Materials science could often be referred to as the 'blue ocean' since there are more to be discovered than what has been excavated so far. On top of this, collaboration with environmental issues is not conventional. Kim is involved in research for integrated environmental monitoring technology, digitizing and managing air, water, and soil pollution. He is looking forward to fuse newly unveiled materials in his research, hoping to bring a constructive result to lay a bridge between materials science and environmental engineering. To set an example, metal-organic frameworks (MOFs) could be used to mitigate environment pollution: volatile organic compounds (VOC) in the air spawns odor while propagating carcinogens if transferred into the human body through the respiratory system. As the material for sensing or removing such hazardous pollutants, MOFs are regarded as one of the highly promising solutions. What is to be underscored here is the infinite possibility of combination of the materials, which are not only capable of being used alone but also of being employed in cooperation with other materials. Kim's research will continue to be centered around mitigating environmental pollution with newly excavated materials. Jeon Chae-yun chaeyun111@hanyang.ac.kr Photos by Choi Min-ju

2017-02 06

[Academics][Researcher of the Month] Al-FCG Ready for Action

Professor Sun Yang-guk of the Department of Energy Engineering is February’s Researcher of the Month for his active role in exploring the field of energy engineering. In his paper, “Compositionally Graded Cathode Material with Long-Term Cycling Stability for Electric Vehicles Application”, Sun explains how adding aluminum into the cathode makes batteries last longer and become more stable compared to other rates of composition. The Al-FCG61 that Sun has developed has shown a high rate of energy efficiency even at 100% depth of discharge (DOD), which draws attention in the field. Sun explains his research with assisted diagrams. As the supply and demand of the electric vehicle is on the rise, most of the batteries in the market last from 150km to 400km, meaning that once the battery is fully charged, the car would move between the distance within. What accounts for the difference is the capacity as to how much cathode can hold up. In order for cars to go beyond 300km at least, the capacity of the cathode would have to be over 200A/h. The only problem to this is that it gets difficult to make it stable and it could blow up. There are various prototypes ranging from generation 1 to generation 4 and the study carried out in Sun's paper is on generation 3. Gradients of different components from inner to outer parts of nickel particle. (Photo courtesy of Sun) Capacity retention, which is the lifespan of a battery, would rise with 61% of nickel with FCG full concentration gradient, which is what Sun has developed in order to create a more stable and long-lasting battery that would hold a larger capacity. Within the mold, Sun has created a two-way particle that contains a high percentage of nickel inside with lower percentage of nickel on the outside. This concentration gradient is created due to the fact that nickel has its advantage of being able to increase the capacity of the battery while it makes the battery more unstable with exothermic reaction. Along with the nickel, Sun has increased the percentage of the manganese inside the particle since it has the advantage of making the cathode more stable. Depth of discharge (DOD) is the rate at which battery is either charged 60% or 100%, and this is tested before electric vehicles are sold for inspection. The average usage of an electric vehicle is at around 2,500 cycles for 10 years, and the Al-FCG has proven to be more energy efficient even at 100%. Most of the batteries do not last long at DOD100 due to the expansion of volume inside the battery. This means that the battery would lose its efficiency as time goes. Al-FCG has shown its Coulombic efficiency rate of 84.5% even at DOD100, while batteries currently in the market show an average of 50% at 2000 cycles. This new battery devised by Sun is not only more energy efficient, but more cost efficient as well. Sun wishes to make more efficient batteries. Sun is continuously researching to keep the DOD level at 100% even after 2000 cycles. With his findings, the electric vehicle industry would definitely benefit hugely in terms of cost and energy efficiency. With different materials, Sun wishes to develop other types of batteries that would bring more comfort to society. Kim Seung-jun nzdave94@hanyang.ac.kr Photos by Kim Youn-soo