▶ Interview
Kisuk Kang, Professor at Department of Materials Science and Engineering
We are entering an era when we realize the depth of environmental issues and the importance of energy. We met Professor Kisuk Kang, regarded as a leader in the domestic secondary battery field, and heard about the more efficient and safer battery technologies he is exploring.
The lithium-ion battery is the most commonly used secondary battery in our daily life. However, conventional lithium-ion batteries, composed of positive and negative electrode materials, electrolytes, and separators, are vulnerable to the risk of fire due to the flammable liquid material of the electrolyte. Furthermore, there is a demand for higher energy density and lower prices for lithium-ion batteries in electric vehicles, drones, and energy storage systems (ESSs). Against this backdrop, the industry and the scientific academia are conducting battery research in two directions. One approach is “Lithium Ion Battery (Ultimate LIB),” which maximizes the performance of lithium-ion batteries, and the other is “Post LIB” technology, which offers a new concept of secondary battery that can overcome the limitations of current LIB. My research team and I are conducting research in both directions.
As I understand, I received the Awards based on various achievements accumulated through extensive research in the secondary battery field. Notable examples are a high-performance electrode made up of “nanocomposite material,” exceeding the limitations of conventional secondary battery anode materials for Ultimate LIB, as well as high-output catalyst applicable to lithium-air batteries that can reduce the weight of secondary batteries and increase energy density for Post LIB. Furthermore, my contributions to technology transfer and removal of technical hurdles in the industry (while conducting research with large domestic companies, such as Samsung SDI, LG Energy Solution, and Hyundai Motor Company) were also considered a valuable accomplishment.
A solid-state battery is a type of battery that replaces the liquid electrolyte, which has potential problems such as leakage and ignition in conventional batteries, with a solid electrolyte. In a theoretical aspect, solid-state batteries are free from the risk of explosion, because the liquid-type flammable organic solvents were eliminated. Moreover, batteries can be shaped into various forms, which enhances their usability. The application of solid-state batteries in manufacturing electric vehicles could result in significant changes to exterior design and interior space, because these batteries are moldable into any shapes in addition to being safer. However, there are several hurdles to overcome for commercialization of solid-state batteries. The most difficult to handle was the risk of a short circuit occurring when lithium penetrates the hard solid electrolyte, and my team and I have uncovered the principle underlying this phenomenon. Although this discovery alone cannot perfect solid-state batteries, it has advanced the commercialization of solid-state batteries one step forward, thereby increasing the odds of success in utilizing solid-state batteries in our daily lives.
In fact, the battery itself may not be considered environment-friendly. This is because the production of a battery requires various chemical materials. In addition to lithium, a battery contains cobalt, nickel, and other heavy metals. Since wastewater and carbon dioxide are also generated, the battery manufacturing process cannot be regarded as environmentally friendly. However, what matters here is that batteries manufactured in this manner can be applied to various environmentally friendly industries. For example, new and renewable energies, such as solar or wind power, struggle with inconsistent power generation depending on the weather and time intervals along the day. Thus, a connection to the current power grid for use is inefficient. This necessitates a “large-capacity battery” system for safe large-scale long-term energy storage.
Contemporary sciences pursues environmental protection as well as convenience. In the same vein, there is a concern over maximizing the environment-friendliness of the manufacturing process in the battery field. There is a need to strike a balance between scientific and technological development and environmental protection. For this purpose, a key strategy would be to transform the benefits we are enjoying from the advancement of science and technology into safer and more effective forms.
