Center for Functional Nanomaterials Seminar

Disorder has emerged as a critical yet underexplored design parameter in governing electrochemical functionality across electrode and electrolyte materials in lithium batteries. In high-Ni layered cathodes, oxygen instability is conventionally attributed to increasing Ni content; however, our findings reveal that oxygen loss originates not from Ni concentration itself but from local transition-metal (TM) disorder. Comparative studies of LiNixCoyMn1–x–yO2 compositions (NCM60 vs. NCM85) show that TM clustering destabilizes the anionic framework by creating energetically unfavorable 3Ni–O configurations, thereby facilitating oxygen vacancy formation and O2 dimerization despite reduced bulk oxygen oxidation. A complementary perspective arises in garnet-type superionic conductors, where disorder in the lattice vibrational spectrum plays a decisive role in enabling ultrafast Li-ion transport. Through Ta doping in Li6.6La3Zr1.63Ta0.4O12 (LLZTO4) relative to Li6.24La3Zr2Al0.24O11.98 (LLZO), we demonstrate that enhanced phonon anharmonicity dynamically diversifies the energy landscape, lowering migration barriers and promoting collective multi-ion motion beyond single-ion hopping limits. Together, these findings establish disorder — whether in cationic sublattices or vibrational dynamics — as a unifying principle that dictates both oxygen stability in cathodes and ion transport in solid electrolytes. This disorder-centered paradigm provides mechanistic insights into degradation and conduction phenomena while offering design strategies for next-generation high-energy-density and solid-state batteries. Yong-Mook Kang completed B.S. (1999), M.S. (2001), and Ph.D. (2004) at Korea Advanced Institute of Science and Technology. He has been a senior researcher at Samsung SDI Co., LTD. He is currently a professor at Department of Materials Science and Engineering in Korea University, South Korea, as well as at KU-KIST Graduate School of Converging Science and Technology, Korea University,. His research area covers electrode or catalyst materials for rechargeable batteries. He has been appointed as RSC (Royal Society of Chemistry) fellow and representative of Korea in 2015, a member of Y-KAST(Young Korean Academy of Science and Technology) in 2020, and an academician of APAM(Asia Pacific Academy of Materials) in 2024.