Investigation of the impact of stacking pressure on a double-layer supercapacitor

There are two important steps necessary for the optimization of electrochemical double-layer capacitors (EDLC): maximizing the volumetric capacitance and minimizing the ohmic resistance. The application of force during the assembly of an EDLC cell is one way to achieve this optimization. The effect of the application of force on the performance characteristics of EDLC cells, assembled using porous activated carbon electrodes, was determined. It was shown that applying force to the body of the cell during assembly only provides a significant increase in the performance of the EDLC with the initial application. The results showed that any increase in the applied force beyond that initial stage does not result in a subsequent increase in performance and can result in a substantial decrease in the performance characteristics of the EDLC cell. Furthermore, it was concluded that the substantial decrease shown was attributed to an alteration of the physical structure of the porous material, which produced significant decreases in the accessible surface area and the material resistance of the activated carbon electrodes. (C) 2010 Elsevier B.V. All rights reserved.