Electrochemical deposition of carbon films on titanium in molten LiCl–KCl–K2CO3

Electrodeposition of carbon films on the oxide-scale-coated titanium has been performed in a LiCl–KCl–K2CO3 melt, which are characterized by scanning electron microscopy, Raman spectroscopy and X-ray diffraction analysis. The electrochemical process of carbon deposition is investigated by cyclic voltammetry on the graphite, titanium and oxide-scale-coated titanium electrodes. The particle-size-gradient carbon films over the oxide-scale-coated titanium can be achieved by electrodeposition under the controlled potentials for avoiding codeposition of lithium carbide. The deposited carbon films are comprised of micron-sized ‘quasi-spherical’ carbon particles with graphitized and amorphous phases. The cyclic voltammetry behavior on the graphite, titanium and oxide-scale-coated titanium electrodes shows that CO32 − ions are reduced most favorably on the graphite for the three electrodes. Lithium ions can discharge under the less negative potential on the electrode containing carbon compared with titanium electrode because of the formation of lithium carbide from the reaction between lithium and carbon.

► Carbon films are prepared on oxide-scale-coated titanium in a LiCl–KCl–K2CO3 melt.
► The films comprise micron-size ‘quasi-spherical’ carbon particles.
► The films present particle-size-gradient.
► The particles contain graphitized and amorphous phases.
► The prepared carbon films are more electrochemically active than graphite.