Transient lithium metal plating on graphite: Operando 7Li nuclear magnetic resonance investigation of a battery cell using a novel RF probe

The development of optimal fast charging protocols requires detailed information regarding lithium inventory in a battery. We built a parallel-plate resonator RF probe and a cartridge-type single layer cell of improved designs. The probe has excellent sensitivity and homogeneity of electromagnetic field, while the cartridge allows easy cell assembly, straight-forward multiplexing, and excellent cell-to-cell data reproducibility. Herein we present our findings from operando 7Li NMR measurements on a graphite//NMC622 cell. The usual/expected sequencing of LixC6 phases from dilute to concentrated observed during charging at low (