Analysis of LIB cathodes by ultra-fast MAS solid state NMR
NMR has been widely used in research and development of lithium ion battery (LIB) because it is able to observe lithium ions directly and thus is extremely useful for characterizing local structure of materials for LIB.
Two types of lithium nuclears, 6Li and 7Li, are NMR observable. 7Li has the much higher sensitivity than 6Li because of higher natural abundance and gyromagnetic moment. However, a solid state NMR analysis of cathode materials using 7Li by conventional MAS frequency ( - 20kHz) has been difficult due to a series of spinning side band (SSB) originated from paramagnetic interaction.
The ultra-fast MAS probes (1mm and 0.75mm) give high resolution and less SSB 7Li spectra. These are available for analyses of degradation behavior of cathode materials.
- 1mm (-80kHz) and 0.75mm (-110kHz) probes
- analysis of microscale sample
- less SSB 7Li spectra
Sampling of a cathode material
Sampling from a cathode sheet.
1mm sample tube
MAS frequency dependence of 7Li spectra
Spectral change before and after cycles
Samples before and after cycles were kindly provided by Prof. Y.Oka (Univ.Hyogo)