Supercapacitor Electrode Based on Mixtures of Graphite and Carbon Nanotubes Deposited Using a Dynamic Air-Brush Deposition Technique

This contribution deals with the fabrication of electrodes and supercapacitor cells using a new dynamic air-brush deposition technique. This method yields highly uniform mats with finely tuned thickness and weight in a completely reproducible way. Using this deposition technique, we analyze the effect of mixtures of CNTs and graphite on the electrode and cell properties (energy, power and capacitance) and observe that with a mixture of 75% of graphite and 25% of CNTs, we increase the power by a factor 2.5 compared to bare CNT-based electrodes. We also analyze the effect of the electrodes' weight first on the capacitance and specific energy and second on the specific power. We report a specific power of 200 kW/Kg and a specific energy of 9.1 Wh/Kg with electrodes having a surface of 2 cm(2) and a weight of 0.25 mg composed by 50% of CNTs and graphite (using a common aqueous electrolyte). Our deposition technique delivers supercapacitors with ad-hoc characteristics, by simply modulating the weight and the concentration of the CNT/graphite mixture in a completely reproducible way and with an industrially suitable and low-cost method. (C) 2013 The Electrochemical Society. [DOI: 10.114912.048304jes] All rights reserved.