Monitoring the evolution of local oxygen environments during LiCoO2 charging via ex situ17O NMR.

LiCoO2 has been labelled with 17O from 17O-enriched water, and then examined via7Li, 17O and 59Co solid-state NMR at different charge states. The results reveal the atomic-level environment evolution during the phase transitions, and 17O NMR is found to be more sensitive to the subtle structural changes.