Strategies to reduce the resistance sources on Electrochemical Double Layer Capacitor electrodes

•Electrode lamination has been optimized by adjusting pressure and temperature.•Low contact resistance has been obtained by applying 50 bar and 160 °C.•Conditions for preserving the electrode porosity are 10 bar and 200 °C.

Electrochemical double layer capacitors (EDLCs) are conceived as high power devices. Generally, power improvement is mainly related to lowering the device impedance (Pmax = V2/4R). However, the supercapacitor impedance is the sum of several contributions (electrolyte, active material, contact between the active material and the current collector, electrode porosity). In this work we demonstrate that the resistance at the interface between the electrode and the current collector and as well the diffusion resistance can be properly controlled during the electrode preparation. In our preparation method the electrodes are compacted by using a hot-press device. During the electrode fabrication parameters such as temperature and pressure are systematically modulated in order to find the best condition for increasing the contact between the electrode and the current collector while maintaining good electrode porosity.