Structural Insight into Protective Alumina Coatings for Layered Li-Ion Cathode Materials by Solid-State NMR Spectroscopy.

Layered transition metal oxide cathode materials can exhibit high energy densities in Li-ion batteries, in particular, those with high Ni contents such as LiNiO. However, the stability of these Ni-rich materials often decreases with increased nickel content, leading to capacity fade and a decrease in the resulting electrochemical performance. Thin alumina coatings have the potential to improve the longevity of LiNiO cathodes by providing a protective interface to stabilize the cathode surface.

Visualization and Chemical Characterization of the Cathode Electrolyte Interphase Using He-Ion Microscopy and Time-of-Flight Secondary Ion Mass Spectrometry.

Unstable cathode electrolyte interphase (CEI) formation increases degradation in high voltage Li-ion battery materials. Few techniques couple characterization of nano-scale CEI layers on the macroscale with chemical characterization, and thus, information on how the underlying microstructure affects CEI formation is lost. Here, the process of CEI formation in a high voltage cathode material, LiCoPO, has been investigated for the first time using helium ion microscopy (HIM) and time-of-flight (ToF) secondary ion mass spectrometry (SIMS).