In situ 7Li and 133Cs NMR Investigations of the Role of Cs+ Additive in Lithium-Metal Deposition Processes

In situ 7Li NMR spectra from live Li-metal batteries with and without Cs+ additives. At discharge voltage point “C,” more microstructured lithium (260 ppm) is recharged back onto the opposite Li electrode to form smoothly deposited Li-metal structures (248 ppm) for the Li-metal battery with Cs additive, thus effectively suppressing the Li-dendrite growth on the Li metal surface.

Scientific Achievement

Insights are obtained into the mechanisms of adding Cs+ to protect the Li-metal electrode during battery cycling.

Significance and Impact

The addition of Cs+ can significantly enhance both the formation of well aligned Li nanorods and the reversibility of the Li electrode. In situ 133Cs NMR directly confirms that Cs+ migrates to the Li electrode to form a positively charged electrostatic shield during the charging process.

Research Details

  • Special symmetric Li planar cells similar to commercial coin cells (except that the stainless container was replaced by a plastic holder) were fabricated for in situ 7Li and 133Cs NMR investigations.
  • The effect of the Cs additive on Li deposition onto Li-metal electrodes was investigated using quantitative in situ 7Li and 133Cs NMR.
  • In situ 7Li NMR showed that a decreased amount of dendrites were formed on Li electrodes during cycling for the battery with Cs additives.
  • In situ133Cs NMR indicated that Cs+ migrated to the Li electrode during the charging process.


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