In situ electrochemical-X-ray Photoelectron Spectroscopy: Rubidium metal deposition from an ionic liquid in competition with solvent breakdown

► Rb electrodeposition from ionic liquid (IL) monitored by in situ electrochemistry-XPS. ► At low current densities Rb electrodeposition possible without IL decomposition. ► At high current densities IL decomposition competes with Rb electrodeposition. ► IL reductive breakdown characterised by carbonisation and rapid loss of fluorine. ► Results are consistent with the reduction of the [NTf2]− anion.