The molten salt electrolytic method for the preparation of nano-structured carbon materials has been subjected to a systematic investigation. It has been confirmed that the electrolysis of molten lithium chloride in the presence of a graphite cathode generates a carbonaceous product that contains nano-structured constituents like particles, fibres and tubes. It has furthermore been found that the precise composition of the product depends critically on a number of process parameters, namely, type of graphite material, reaction temperature, electrochemical polarisation regime, and reaction time. After careful optimisation of these parameters, it has become possible to achieve a content of nanotubes in the carbonaceous product of approximately 80%. This exceeds by far the results of all previous studies using this approach. The nanotubes synthesised are multi-walled with varying diameters and highly curved, and they occur in the form of aggregates of considerable size.