Preparation of modified cokes and/or blacks

This invention relates to a process for the preparation of carbon materials, in particular to the preparation of carbon materials of high intercalation capacity, to products obtained thereby and to their use in electrochemical cells Modified cokes or blacks suitable as alkali metal intercalation electrodes in electrochemical cells are produced by a method comprising boiling the coke or black in concentrated hydrochloric acid, flushing with distilled water, sonicating the coke or black in acetone, and drying the coke or black at a temperature of 150 to 300° C. The modified cokes and blacks produced by this method show Intercalation capacities up to 50% higher than unmodified cokes and blacks, and maintain the high electrolyte compatibility, rate capability and cyclability of the cokes or blacks.