In this paper, the degradation processes of commercial supercapacitors aged at 2.7 V and 65°C for 2000 h were studied. The crystallinity, thermal stability, and specific surface areas of the carbon electrodes of the supercapacitors were measured. Significant changes and degradations in the carbon electrodes were observed for the aged supercapacitors. New functional groups were also found on the surface of the electrodes. The degradation of the lattice structures and the reduction in the specific surface area were as well observed for the aged supercapacitors. It was suggested that the aging of supercapacitors significantly changed the electrode surface which affects considerably electrical properties and functionality of supercapacitors. We have also performed experiments which suggest that the aging effect on the electrode is not uniformly distributed through its length.