Phase Transition Behavior of Layer-structured Cathode Materials for Lithium-ion and Sodium-ion Batteries
Abstract: Layer-structured transition-metal oxides are the most promising cathode materials for Lithium-ion and Sodium-ion batteries. These compounds such as LiMO2 (M = Co, Ni, Mn) generally show lattice parameter ‘a’(‘b’) contracts and ‘c’ expands during charge. During discharge, the changes of parameters reverse directions. However, for some layered compounds such as LiVO2 or Li2MoO3, the lattice parameter change during charge and discharge is in different direction. They show ‘a’(‘b’) expansion during charge, and contraction during discharge. It is an “abnormal” unit cell breathing behavior. We use Li2MoO3 as a model compound with abnormal lattice parameter changes to study the abnormal unit-cell breathing behavior. A general relationship between the lattice parameter changes and the electronic structure of both “normal” and “abnormal” layer-structured transition metal oxide compounds upon charging is proposed.
In addition, a series of new layered cathode materials for sodium-ion batteries are developed. Their phase transition behaviors during charge and discharge are quite different from the cathode materials for lithium-ion batteries, and featured by some interesting characteristics. The indepth understanding of phase transition behavior is vital important for designing high performance cathode materials for Lithium-ion and Sodium-ion batteries.
Biography: Yong-Ning Zhou is a professor at Fudan University. He received his Ph.D degree in materials physics and chemistry from Department of Materials Science at Fudan University in 2010. From 2010-2012, he worked as a postdoctor in Department of Chemistry at Fudan University. From 2012-2015, he worked as a research associate at Brookhaven National Laboratory, USA. Since July 2015, he joined in Fudan University as a young professor. He is a recipient of 1000 Youth Talents Program from China government. His research interests focus on the structure evolution and reaction mechanism of electrode materials for Li-ion and Na-ion batteries, as well as solid-state batteries. He has authored and co-authored more than 70 peer-reviewed journal publications, including Nature Communications, Advanced Energy Materials etc., and filed 6 patents.