Long-term cycling of carbon-based supercapacitors in aqueous media
- Electrochimica Acta, 54(19), p.4481-4486, 2009 .
The behaviour of mesophase-derived electrodes on long-duration cycling conditions was studied in 1M sulfuric acid and 6M potassium hydroxide. Variation in the specific capacitance values with the number of cycles shows a good cycling life performance in acidic media but very poor in an alkaline electrolyte. The total loss of capacitance after 7000 cycles in acidic media is 8 x cent at 0.6V and 16 x cent at 1 V, whereas in the basic electrolyte the reduction in the capacitance values is 72 x cent, even at a very small operating voltage (0.6 V). This behaviour was associated to the strong oxidation of the positive electrode caused by the progressive shift of the working potential towards very positive potential values during cycling.