Electrochemical behavior of a carbonaceous mesophase sphere/activated carbon composite

Carbonaceous mesophase spheres and medium coal tar pitch with a weight ratio of 3 were mixed in absolute ethanol solution,to which KOH was added to form a slurry.The slurry was heated to 800 ℃ to carry out KOH activation.The structure of the resulting material was examined by scanning electron microscopy and X-ray diffraction.Electric double layer capacitors and half-cells were fabricated to investigate its electrochemical performance.The material exhibited good performance in both LiPF6/(ethylene carbonate + dimethyl carbonate) and Et4NBF4/acetonitrile electrolytes with a high reversible capacity of 306.6 mAh/g(0.2 C) in the half-cell and a capacitance of 25.8 F/g in the capacitor.The material showed a favorable rate performance and good cycle stability.