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

The effects of cell assembly compression on the performance of carbon electrochemical double-layer capacitor electrodes

“…It was concluded that the application of force altered the physical structure of the activated carbon electrodes, resulting in a decrease in the accessible surface area and a displacement of the electrolyte, a phenomenon also known as 'electrolyte starvation'. The AC impedance response of an electrode in this state also supported these conclusions, as was seen by the change in the distribution of the total capacitance and the decrease in the values of the individual RC time constants [13].…”

“…In this evaluation, carbon electrodes were prepared from eight different carbons and were tested in triplicate experiments using the same protocols as was previously defined in our prior work [13]. It would be expected that different activated carbons would exhibit different behaviors as a result of variations in their porous structure.…”

Ultrafast charge and discharge biscrolled yarn supercapacitors for textiles and microdevices

“…The strong physical contact caused by compressive forces generated during plying results in a low ESR 33 . The ESR measured dramatically decreased from 110.4 to 8.5 O (at 1 kHz) when an unplied biscrolled electrode was replaced by an electrode of yarn plied with Pt wire, and this resistance decrease can also be seen in the decrease of the diameter of the Nyquist semi-circle ( Supplementary Fig.…”

Using coin cells for ultracapacitor electrode material testing

“…The graphs show that, in general, the measured ultracapacitor performance increases (specific capacitance increases and ESR decreases) as pressure is applied up until approximately a ratio of 1.2-1.3 upon which additional pressure causes the specific capacitance to begin decreasing. This could be due to the electrode material collapsing making it increasingly more difficult for the electrolyte to access the pores [2], or due to the separator material distorting and preventing good ionic conduction of the electrolyte. At less than optimum Fig.…”

“…The ESR can be reduced through improved physical contact between the electrodes and current collectors [2]. For a packaged ultracapacitor, force is applied during assembly and testing to insure good contact between cell components.…”