Investigation of Electroless-Electrolytic Ni-Mo Binder-Free Electrode for Ultracapacitor Applications

This paper provides results of a thin film binder-free Ni-Mo electrode ultracapacitor that was fabricated by using electroless-electrolytic (EE) technique with a glass fiber separator and 0.5M Na₂SO₄electrolyte solution.

Galvanic cycles were performed to characterize the charge/discharge curves of the Ni-Mo ultracapacitor at different currents as shown in figures 1 & 2. The capacitance was then analyzed by using equation (1).

where C is the capacitance normalized by the geometric area of the electrode, I is the current set to the cell and Ais the geometric area.

Figure 3 illustrates the capacitance relationship between 0.1 and 0.5 mA. From the plot it seems that at 0.1 mA the capacitance is more consistent and larger than at 0.5 mA. This can be because looking at the galvanic cycles for 0.5 mA we see a bend in the curve which can occur from the internal resistance being large. ^[1]

We will explore options and approaches to smoothing the curves to not only get a better capacitance values but obtained more consistent capacitance over different current rates.

References

1. Steven Risser, Elvin Beach, Megan Moore and Olga Koper, “Application of Metal Oxide Supercapacitor for Naval Applications”, ASNE Proceedings (2012)