Towards improved high capacity layered electrode materials for Liion batteries through atomic-level understanding of the redox reactions.

Rechargeable Li-ion batteries are a pillar of our current technology driven society. More energy per mass unit can be stored in layered high capacity cathodes but they suffer from the voltage fade and voltage hysteresis reducing their energy efficiency. These detrimental effects mainly originate from the structural changes in the cathode material during charge and discharge. Recent developments have led to a paradigm shift, by showing that in these promising cathodes the oxygen oxidation, contributing to high capacity, is inherently linked with transition metal cation migration upon cycling. Together, they cause the voltage hysteresis and voltage fade. Gaining understanding of the complex interplay and control over both is necessary to exploit the advantages while eliminating the detrimental effects. To monitor both effects systematically and separate from the influence of the microstructure, we will synthesize new model structures with dedicated structural variations of the initial crystal structure and microstructure. We will study their structural changes upon cycling with state-of-the-art structure characterization techniques, and relate them to the electrochemical properties. This project will thus result in new viable Li-ion battery cathodes and allow the comprehensive understanding of the role of the microstructure, local structure and local valence for the stability of Li-rich layered cathodes, major candidates for future advanced rechargeable Li-ion batteries.

Keywords:MICROSCOPY (TEM)

Disciplines:Materials physics not elsewhere classified, Solid state chemistry

Project type:Collaboration project