□ A joint research team led by Professors Lee Hong-kyung, Lee Yong-min, and Lee Ho-chun of the Department of Energy Science and Engineering, DGIST (President: Kuk Yang) developed a new concept system that can dramatically improve the stability and lifespan of next-generation batteries. It is expected to solve the problem of dendrite growth, which is a difficult problem in next-generation lithium metal batteries, by turning liquid electrolyte into a dynamic state, thereby accelerating the commercialization of next-generation batteries.
□ Currently, most commercialized batteries such as electric vehicles use graphite electrodes as negative electrodes. A graphite negative electrode has limitations in terms of energy density because it is heavy and occupies a lot of space inside the battery. Since this limits long battery operation, the demand for a lighter and smaller anode material has been growing.
□ ‘Lithium metal’ is in the limelight as a next-generation anode material that can solve these problems. However, commercializing lithium metal anodes is hindered by the generation of ‘dendrite,’ a twig-shaped crystal that accumulates on the surface of the anode during the lithium battery charging process. This tends to be heavily dependent on the ion transport phenomenon in the electrolyte. In other words, when the ion transport velocity is faster and the homogeneity is improved, it is easier to control dendrite.
□ There were consistent efforts to suppress dendrite, but it was necessary to break away from the classical ion transport method to come up with a faster and more homogeneous ion transport method.
□ The research team produced a nano-spinbar (hereinafter, “NSB”) that responds to an external magnetic field so that the static electrolyte solution in the battery can be turned to a dynamic state and added it to the electrolyte solution to generate micro-convection. In fact, it is possible to rotate NSBs distributed throughout the electrolyte by applying an external rotating magnetic field to transmit power remotely. As a result, it facilitated fast ion transport while reducing ion diffusion by about 32% compared to the previous method, thus enabling homogeneous ion transportation.
□ The dynamic ion transport realized through the application of magnetic nanoparticles (NSB) and an external magnetic field can promote rapid and uniform transport of lithium ions, and it has been verified that it is effective in controlling dendrite formation and growth even at high charging rates. The same effect could be achieved when they were added to other electrolytes. If a lithium metal battery is manufactured with the electrolyte developed by this research team and use it while applying a rotating magnetic field on the outside, it can dramatically improve lifespan compared to the existing system.
□ Professor Lee Hong-kyung of the Department of Energy Science and Engineering at DGIST said, “It is a new concept electrolyte system that can create a dynamic electrolyte that has never been attempted before and change the paradigm of electrolyte research through magnetic nanoparticles,” and added, “It can be immediately applied to various electrochemical systems using liquid electrolytes.”
□ Meanwhile, this research was published in the July 22 issue of 'Advanced Functional Materials,' an international journal in the field of materials engineering, and was selected as the cover study in recognition of its excellence. This research was carried out with support from the Ministry of Trade, Industry and Energy's Industrial Technology Innovation Project and the POSCO TJ Park Foundation, along with the National Research Foundation of Korea's Excellent New Research, Basic Research Laboratory, and Nano and Materials Technology Development Projects.
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