Study of the local structure of cathode materials for Li-ion batteries upon charging

Datum: 18 januari 2019

Locatie: UAntwerp, Campus Groenenborger, room V.009 - Groenenborgerlaan 171 - 2020 Antwerp (Wilrijk) (route: UAntwerpen, Campus Groenenborger)

Tijdstip: 11.30 - 12.30 uur

Organisatie / co-organisatie: EMAT

Korte beschrijving: Friday Lecture by Mylène Hendrickx (EMAT)

About the lecture

Li-ion batteries are widely employed in portable devices such as smartphones, laptops, digital cameras, etc. However, their cost, life time, safety and performance still require some improvement for their applicability in automotive applications. The performance of Li-ion batteries largely depends on the cathode materials, which are mostly based on mixed Li and transition metal (TM) oxides.

Upon charging and discharging, some irreversible electronic and structural changes occur that are directly related to the failure of the battery described by the capacity loss, voltage fade and oxygen loss of the cathode material. Therefore, a thorough transmission electron microscopy (TEM) structural investigation is needed to understand the origin of these irreversible changes, which can provide insight into the choice of cation substitution that improves the stability of the structure.

Lithium nickel manganese cobalt oxides (NMC) in particular are a leading contender for automotive applications. The local structure of NMC and Sn-substituted NMC is up till now only studied using TEM in ex-situ experiments. However, ex-situ experiments are not sufficient to solve all the questions, and leaves room for misinterpretation of artifacts due to air exposure, vacuum exposure and relaxation as being real cycling related changes. Therefore, we want to apply in-situ electron diffraction tomography using the Liquid Stream holder, which will allow us to study charging and discharging in the TEM.