Lithium button cells with electrodes made of nickel-manganese-cobalt oxides (NMC) are very powerful. Unfortunately, their capacity decreases over time. Now, for the first time, a team has used a non-destructive method to observe how the elemental composition of the individual layers in a button cell changes during charging cycles.

The study, published in the journal Small, involved teams from the Physikalisch-Technische Bundesanstalt (PTB), the University of Münster, researchers from the SyncLab research group at HZB and the BLiX laboratory at the Technical University of Berlin. Measurements were carried out in the BLiX laboratory and at the BESSY II synchrotron radiation source.

Lithium-ion batteries have become increasingly better. The combination of layered nickel-manganese-cobalt oxides (NMC) with a graphite electrode (anode) has been well established as the cathode material in button cells and has been continuously improved. However, even the best batteries do not last forever; they age and lose capacity over time.