Display omitted •An Electrochemical-Chemical-Electrochemical mechanism of carbon dioxide electroreduction in molten salts is proposed.•The electroreduction of CO2 to solid phase carbon in molten chlorides can be taken as the basis of electrochemical synthesis of various nanoscale carbonaceous materials: multiwalled tubes, fibers, amorphous carbon and crystalline graphite.•The possibility of doping nanostructured carbon materials with metals (Fe, Pt) in one step during synthesis has been shown. Electrochemical synthesis in molten salts has great possibilities for the production of various carbonaceous materials (graphite, graphene, ultra-fine amorphous carbon, doped and undoped carbon nanotubes and fibers) in one step in the form of films and ultra-fine powders. Carbon dioxide dissolved in molten salts under excess pressure can be a carbon precursor during the synthesis. The peculiarities of electrochemical reduction of carbon in solid state from CO2 were studied by cyclic votammetry. The mechanisms of cathodic and anodic processes were suggested. The conditions (composition of electrolytic bath, temperature, cathodic current density, bath potential) of electrochemical synthesis of nanoscale carbon materials were determined. The properties of the produced carbon-containing products were analyzed by XRD, SEM, TEM, ED, Raman spectroscopy. A correlation of product properties with synthesis conditions and parameters has been made.