Colin Fernandes1 Leonard MacEachern1 Steven McGarry1

1, Carleton University, Ottawa, Ontario, Canada

With a growing demand for autonomous sensors, the development of on-chip supercapacitors is becoming a promising energy storage solution. This study investigates the electrospinning process for direct on silicon deposition of poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT:PSS) for ultrahigh surface area porous electrodes as a method of low-cost additive fabrication of electrolytic double layer (EDL) capacitors for powering microelectronic circuits.
The process under development uses the addition of all components of the supercapacitor structure directly on the silicon surface. Electrospun PEDOT:PSS/poly(vinyl alcohol) (PVA)/poly(ethylene oxide) (PEO) nanofiber mats are utilized as both the anode and cathode with PEO/Lithium Perchlorate (LiClO4)/ Propylene Carbonate (PC) as the gel electrolyte of the supercapacitor structure. The study focuses on investigating methods to reduce electrode/electrolyte resistance and increasing energy density, while utilizing the practicality of a gel electrolyte. The PEDOT:PSS nanofibers containing PEO/PVA introduced as a carrier polymer in the electrospinning solution are investigated as domains for the electrolyte gelling throughout electrode volume [1]. The incorporation of PEO/PVA is hypothesised to increase the ion mobility and gel electrolyte access to PEDOT:PSS surfaces encouraging more ELD formation, while PEO has demonstrated high stability and consistency in the electrospinning process [2]. The energy densities of PEO and PVA incorporated fibers are compared against Dimethyl Sulfoxide (DMSO) treated fibers (removing the carrier polymers while improving conductivity of the PEDOT:PSS). The properties of the supercapacitor structure presented above are analyzed using SEM imaging of the nanofiber morphologies, Cyclic Voltammetry (CV), Impedance Spectroscopy (IS), and DC charge/discharge analysis. The study’s results and comparisons to state of the art ELD capacitors will be presented [3].

[1] N. Chodankar, D. Dubal, A. Lokhande and C. Lokhande, "Ionically conducting PVA–LiClO 4 gel electrolyte for high performance flexible solid state supercapacitors", Journal of Colloid and Interface Science, vol. 460, pp. 370-376, 2015.
[2] R. Rošic, J. Pelipenko, P. Kocbek, S. Baumgartner, M. Bešter-Rogač and J. Kristl, "The role of rheology of polymer solutions in predicting nanofiber formation by electrospinning", European Polymer Journal, vol. 48, no. 8, pp. 1374-1384, 2012.
[3] N. Kyeremateng, T. Brousse and D. Pech, "Microsupercapacitors as miniaturized energy-storage components for on-chip electronics", Nature Nanotechnology, vol. 12, no. 1, pp. 7-15, 2016.