Carbon materials were synthesized by the pyrolysis of acrylonitrile-butadiene-styrene terpolymer (ABS) under different heat treatment conditions. ABS decomposed in a rapid single-step reaction, which was completed around 600°C. X-ray diffraction studies indicated a disordered carbon structure with a large number of single layer carbon sheets. It was found that varying the soak time, pyrolysis temperature and heating rate greatly affected the compositional, structural and electrochemical characteristics of the carbonaceous products. Charge–discharge studies of the product obtained by a 1h pyrolysis at 600°C at a heating rate of 20°C/min exhibited first-cycle lithium insertion and deinsertion capacities of 825 and 564mAh/g, respectively. Subsequent cycles showed a remarkable improvement in cycling efficiency with a 10th cycle efficiency of 100%.