The electrochemical deposition of carbon materials has been performed in LiCl-Li2CO3 melts using a Pt anode and a nickel cathode. Cyclic voltammetry and constant voltage electrolysis are conducted to investigate the electrode reactions, and the results prove that solid carbon is the only product from the cathodic reduction. Short-term electrolysis at 750 °C for 3, 10 and 20 s has been applied to study the formation and growth of the varied carbon microstructures. All of the results demonstrate that the morphologies of the deposited carbon are significantly affected by the cathode substrates, which may show different catalyzing effects on carbon nucleation. Two primary morphologies, quasi-spherical and nanofiber structures are observed at the nickel plate cathodes during the electrolysis and the formation and growth of carbon nanofibers are easily enhanced by using a high cell voltage. However, only a quasi-spherical structure is found on the molybdenum cathode substrate.